Science.gov

Sample records for stability indicating rp-hplc

  1. Rapid Analysis of Glibenclamide Using an Environmentally Benign Stability-Indicating RP-HPLC Method

    PubMed Central

    Haq, Nazrul; Alanazi, Fars Kaed; Alsarra, Ibrahim Abdullah; Shakeel, Faiyaz

    2014-01-01

    An environmentally benign RP-HPLC approach for rapid analysis of glibenclamide in pure form, developed nanoemulsion and commercial tablets was developed and validated in present investigation. The green chromatographic identification was performed on Lichrosphere 250 X 4.0 mm RP C8 column having a 5 μm packing as a stationary phase using a combination of ethanol: methanol (50:50 % v/v) as a mobile phase, at a flow rate of 1.0 mL/min with UV detection at 245 nm. The proposed method was validated for linearity, selectivity, accuracy, precision, robustness, sensitivity and specificity as per international conference on harmonization (ICH) guidelines. The utility of proposed method was verified by assay of glibenclamide in developed nanoemulsion and commercial tablets. The proposed method was found to be satisfactory in terms of selectivity, precision, accuracy, robustness, sensitivity and specificity. The content of glibenclamide in developed nanoemulsion and commercial tablets was found to be 100.50 % and 99.15 % respectively. The proposed method successfully resoled glibenclamide peak in the presence of its all type of degradation products which indicated stability-indicating property of the proposed method. These results indicated that the green chromatographic method could be successfully employed for routine analysis of glibenclamide in pure drug and various commercial formulations. PMID:25276186

  2. Rapid Analysis of Glibenclamide Using an Environmentally Benign Stability-Indicating RP-HPLC Method.

    PubMed

    Haq, Nazrul; Alanazi, Fars Kaed; Alsarra, Ibrahim Abdullah; Shakeel, Faiyaz

    2014-01-01

    An environmentally benign RP-HPLC approach for rapid analysis of glibenclamide in pure form, developed nanoemulsion and commercial tablets was developed and validated in present investigation. The green chromatographic identification was performed on Lichrosphere 250 X 4.0 mm RP C8 column having a 5 μm packing as a stationary phase using a combination of ethanol: methanol (50:50 % v/v) as a mobile phase, at a flow rate of 1.0 mL/min with UV detection at 245 nm. The proposed method was validated for linearity, selectivity, accuracy, precision, robustness, sensitivity and specificity as per international conference on harmonization (ICH) guidelines. The utility of proposed method was verified by assay of glibenclamide in developed nanoemulsion and commercial tablets. The proposed method was found to be satisfactory in terms of selectivity, precision, accuracy, robustness, sensitivity and specificity. The content of glibenclamide in developed nanoemulsion and commercial tablets was found to be 100.50 % and 99.15 % respectively. The proposed method successfully resoled glibenclamide peak in the presence of its all type of degradation products which indicated stability-indicating property of the proposed method. These results indicated that the green chromatographic method could be successfully employed for routine analysis of glibenclamide in pure drug and various commercial formulations.

  3. A Rapid Stability-Indicating RP-HPLC Method for the Determination of Betaxolol Hydrochloride in Pharmaceutical Tablets

    PubMed Central

    Auvity, Sylvain; Chiadmi, Fouad; Cisternino, Salvatore; Fontan, Jean-Eudes; Schlatter, Joël

    2013-01-01

    A stability-indicating reversed-phase high performance liquid chromatography (RP-HPLC) method was developed for the determination of betaxolol hydrochloride, a drug used in the treatment of hypertension and glaucoma. The desired chromatographic separation was achieved on a Nucleosil C18, 4 μm (150 × 4.6 mm) column, using isocratic elution at a 220 nm detector wavelength. The optimized mobile phase consisted of a 0.02 M potassium dihydrogen phosphate: methanol (40:60, v/v, pH 3.0 adjusted with o- phosphoric acid) as solvent. The flow rate was 1.6 mL/min and the retention time of betaxolol hydrochloride was 1.72 min. The linearity for betaxolol hydrochloride was in the range of 25 to 200 μg/mL. Recovery for betaxolol hydrochloride was calculated as 100.01%–101.35%. The stability-indicating capability was established by forced degradation experiments and the separation of unknown degradation products. The developed RP-HPLC method was validated according to the International Conference on Harmonization (ICH) guidelines. This validated method was applied for the estimation of betaxolol hydrochloride in commercially available tablets. PMID:23531643

  4. A validated specific stability-indicating RP-HPLC assay method for the determination of loteprednol etabonate in eye drops.

    PubMed

    Han, Yong K; Segall, Adriana I

    2015-01-01

    A new stability-indicating RP-HPLC assay method was developed and validated for quantitative determination of loteprednol etabonate in bulk drugs and in ophthalmic suspensions in the presence of degradation products generated from forced degradation studies. The system consisted of Agilent Technologies Zorbax Eclipse XDB-Phenyl 5 µm 4.6 × 250 mm, and detection was performed at 244 nm. The mobile phase consisted of water-acetonitrile-acetic acid (34.5:65.0:0.5, v/v/v) run at a flow rate of 1 mL/min and maintained at room temperature. The calibration curve was linear from 30 to 70 µg/mL with r > 0.999. Accuracy (mean recovery 100.78%) and precision were found to be satisfactory. Stress conditions including acid and alkali hydrolysis, water stress, oxidation, photolysis and heat were applied. The degradation products did not interfere with the detection of loteprednol etabonate, thus the method can be considered as a stability-indicating method. The proposed method can be used for quality control assay of loteprednol etabonate in bulk drug and in ophthalmic suspensions and for stability studies as a result of the ability of the method to separate loteprednol etabonate from its degradation products and excipients.

  5. Stability-Indicating RP-HPLC Method for Simultaneous Estimation of Enrofloxacin and Its Degradation Products in Tablet Dosage Forms

    PubMed Central

    Chakravarthy, V. Ashok; Sailaja, B. B. V.; Kumar, Avvaru Praveen

    2015-01-01

    The present work was the development of a simple, efficient, and reproducible stability-indicating reverse-phase high performance liquid chromatographic (RP-HPLC) method for simultaneous determination enrofloxacin (EFX) and its degradation products including ethylenediamine impurity, desfluoro impurity, ciprofloxacin impurity, chloro impurity, fluoroquinolonic acid impurity, and decarboxylated impurity in tablet dosage forms. The separation of EFX and its degradation products in tablets was carried out on Kromasil C-18 (250 × 4.6 mm, 5 μm) column using 0.1% (v/v) TEA in 10 mM KH2PO4 (pH 2.5) buffer and methanol by linear gradient program. Flow rate was 1.0 mL min−1 with a column temperature of 35°C and detection wavelength was carried out at 278 nm and 254 nm. The forced degradation studies were performed on EFX tablets under acidic, basic, oxidation, thermal, humidity, and photolytic conditions. The degraded products were well resolved from the main active drug and also from known impurities within 65 minutes. The method was validated in terms of specificity, linearity, LOD, LOQ, accuracy, precision, and robustness as per ICH guidelines. The results obtained from the validation experiments prove that the developed method is a stability-indicating method and suitable for routine analysis. PMID:25705547

  6. Stability-indicating RP-HPLC method for the simultaneous determination of escitalopram oxalate and clonazepam.

    PubMed

    Kakde, Rajendra B; Satone, Dinesh D; Gadapayale, Kamalesh K; Kakde, Megha G

    2013-07-01

    The objective of the current study was to develop a validated, specific stability-indicating reversed-phase liquid chromatographic (LC) method for the quantitative determination of escitalopram oxalate and clonazepam and their related substances in bulk drugs and pharmaceutical dosage forms in the presence of degradation products. Forced degradation studies were performed on the pure drugs of escitalopram oxalate and clonazepam, as per the stress conditions prescribed by the International Conference on Harmonization (ICH) using acid, base, oxidation, thermal stress and photolytic degradation to show the stability-indicating power of the method. Significant degradation was observed during acid and alkaline hydrolysis and no degradation was observed in other stress conditions. The chromatographic method was optimized using the samples generated from forced degradation studies. Good resolution between the peaks corresponded to the active pharmaceutical ingredients, escitalopram oxalate and clonazepam, and degradation products from the analyte were achieved on an ODS Hypersil C18 column (250 × 4.6 mm) using a mobile phase consisting of a mixture of acetonitrile-50 mM phosphate buffer + 10 mM triethylamine (70:30, v/v). The detection was conducted at 268 nm. The limit of detection and the limit of quantitation for escitalopram oxalate and clonazepam were established. The stress test solutions were assayed against the qualified working standards of escitalopram oxalate and clonazepam, which indicated that the developed LC method was stability-indicating. Validation of the developed LC method was conducted as per ICH requirements. The developed LC method was found to be suitable to check the quality of bulk samples of escitalopram oxalate and clonazepam.

  7. Validated stability-indicating assay method for simultaneous determination of aceclofenac and thiocolchicoside using RP-HPLC.

    PubMed

    Samanthula, G; Shrigod, V V; Patel, P N

    2014-08-01

    A rapid, accurate, precise, robust and specific stability indicating RP-HPLC method has been developed and validated for simultaneous determination of fixed dose combination of Aceclofenac (ACF) and Thiocolchicoside (THC). Combinations and marketed tablets were subjected to stress conditions such as oxidation, hydrolysis, photolysis and heat. Successful separation of drugs from stress degradation products was achieved on Kromasil C18 (250 × 4.6 mm, 5 μm) column at 30 °C using gradient mobile phase system consisting of (A) 10 mM ammonium acetate pH 5.00 buffer and (B) acetonitrile: water (70:30 v/v). The flow rate was 1.0 mL/min with UV detection at 265 nm. The retention time of THC and ACF was 13.29 and 22.20 min respectively. Peak purity of both the drugs was passing in all degradation conditions demonstrates the specificity of assay method for their estimation in presence of degradation products. The developed HPLC method was validated for linearity, accuracy, precision and robustness. The linearity of the proposed method was investigated in the range of 80-280 µg/mL for ACF and 6.4-22.4 µg/mL for THC. The utility of the procedure was verified by its application to marketed formulations.

  8. New Stability-Indicating RP-HPLC Method for Determination of Diclofenac Potassium and Metaxalone from their Combined Dosage Form

    PubMed Central

    Panda, Sagar Suman; Patanaik, Debasis; Ravi Kumar, Bera V. V.

    2012-01-01

    A simple, precise and accurate isocratic RP-HPLC stability-indicating assay method has been developed to determine diclofenac potassium and metaxalone in their combined dosage forms. Isocratic separation was achieved on a Hibar-C18, Lichrosphere-100® (250 mm × 4.6 mm i.d., particle size 5 μm) column at room temperature in isocratic mode, the mobile phase consists of methanol: water (80:20, v/v) at a flow rate of 1.0 ml/min, the injection volume was 20 μl and UV detection was carried out at 280nm. The drug was subjected to acid and alkali hydrolysis, oxidation, photolysis and heat as stress conditions. The method was validated for specificity, linearity, precision, accuracy, robustness and system suitability. The method was linear in the drug concentration range of 2.5–30 μg/ml and 20–240 μg/ml for diclofenac potassium and metaxalone, respectively. The precision (RSD) of six samples was 0.83 and 0.93% for repeatability, and the intermediate precision (RSD) among six-sample preparation was 1.63 and 0.49% for diclofenac potassium and metaxalone, respectively. The mean recoveries were between 100.99–102.58% and 99.97–100.01% for diclofenac potassium and metaxalone, respectively. The proposed method can be used successfully for routine analysis of the drug in bulk and combined pharmaceutical dosage forms. PMID:22396909

  9. Stability-Indicating RP-HPLC Method for Determination of Tamsulosin HCL in Pharmaceutical Dosage Form

    PubMed Central

    Kumar, G S; Kumar, B Sai Pavan

    2012-01-01

    A selective, specific and sensitive stability-indicating high-performance liquid chromatographic method was developed and validated for the determination of Tamsulosin in in pharmaceutical dosage forms. Celecoxib was used as Internal Standard (IS). The chromatographic conditions comprised of a reversed-phase Lichrocart / Lichrosphere C18 column (250 × 4.0 mm packed with 5) with mobile phase consisting of a mixture of Acetonitrile: T.D.W. in the ratio (40: 60). Flow rate was 0.8 mL / min. Detection was carried out at 275 nm. The retention time of Tamsulosin HCl and Celecoxib were found to be 1.608 and 2.767min respectively and the linear regression analysis data for the calibration plots showed good linear relationship in the concentration range 1 - 200 g/mL. The value of correlation coefficient, slope and intercept were, 0.9995, 0.7453 and 0.4584, respectively. Tamsulosin HCl was subjected to stress conditions of degradation in aqueous solutions including acidic, alkaline, oxidation, photolysis and thermal degradation. The developed method was validated with regard to linearity, accuracy, precision, selectivity and robustness and the method was found to be precise, accurate, linear and specific. The method was employed successfully for identification and determination of Tamsulosin in pharmaceutical preparations. PMID:24826033

  10. Stability Indicating RP-HPLC Estimation of Atorvastatin Calcium and Amlodipine Besylate in Pharmaceutical Formulations

    PubMed Central

    Shah, D. A.; Bhatt, K. K.; Mehta, R. S.; Baldania, S. L.; Gandhi, T. R.

    2008-01-01

    A simple, specific, accurate and stability indicating reversed phase high performance liquid chromatographic method was developed for the simultaneous determination of atorvastatin calcium and amlodipine besylate in tablet dosage forms. A phenomenex Gemini C-18, 5 μm column having 250×4.6 mm i.d. in isocratic mode, with mobile phase containing 0.02 M potassium dihydrogen phosphate:acetonitrile:methanol (30:10:60, v/v/v) adjusted to pH 4 using ortho phosphoric acid was used. The flow rate was 1.0 ml/min and effluents were monitored at 240 nm. The retention times of atorvastatin calcium and amlodipine besylate were 11.6 min and 4.5 min, respectively. The calibration curves were linear in the concentration range of 0.08-20 μg/ml for atorvastatin calcium and 0.1-20 μg/ml for amlodipine besylate. Atorvastatin calcium and amlodipine besylate stock solutions were subjected to acid and alkali hydrolysis, chemical oxidation and dry heat degradation. The degraded product peaks were well resolved from the pure drug peak with significant difference in their retention time values. The proposed method was validated and successfully applied to the estimation of atorvastatin calcium and amlodipine besylate in combined tablet dosage forms. PMID:21369436

  11. Development and Validation of a Stability-Indicating RP-HPLC Method for the Assay of Pristinamycin in Bulk and Tablet Dosage Form

    PubMed Central

    Mallikarjuna Rao, Nagasarapu; Gowrisankar, Dannana

    2016-01-01

    Pristinamycin is an antibiotic used mainly in the treatment of Staphylococcus infections. The aim of this study was to develop a rapid and simple stability-indicating RP-HPLC method for the determination of pristinamycin in tablet dosage form. Pristinamycin was eluted on the ACE-5, C18-HL, 250 x 4.6 mm, 5 µm analytical column with a mobile phase consisting of 0.2% orthophosphoric acid and acetonitrile 63:37 v/v, pumped at 1.5 ml/min flow rate. The column was maintained at 40°C and 10 μl of the solutions were injected. UV detection was performed at 206 nm. The procedure separated pristinamycin and its potential degradation products in an overall analysis time of less than 10 min with pristinamycin eluting at about 3 min. The method was validated according to the regulatory guidelines with respect to specificity, precision, accuracy, linearity, and robustness. Forced degradation studies were also performed for pristinamycin bulk drug samples to demonstrate the stability-indicating power of the HPLC method. The % RSD of system precision and method precision was found to be 0.64 and 1.49%, respectively. The procedure provided a linear response over the concentration range 25–150 μg/ml (r = 0.9998). Finally, the applicability of the method was evaluated in the tablet dosage form as well as in stability samples. PMID:27222604

  12. Development of a simple and stability-indicating RP-HPLC method for determining olanzapine and related impurities generated in the preparative process.

    PubMed

    Cui, Daoping; Li, Yueqing; Lian, Mingming; Yang, Feng; Meng, Qingwei

    2011-08-07

    A simple and stability-indicating reverse phase high performance liquid chromatographic (RP-HPLC) method was developed and validated for the determination of olanzapine (OLN) and related impurities in bulk drugs. Eight impurities were characterized respectively, and particularly a new process impurity from OLN synthesis was structurally confirmed as 1-(5-methylthionphen-2-yl)-1H-benzimidazol-2(3H)-one (Imp-7) by X-ray single crystal diffraction, MS, (1)H NMR, (13)C NMR and HSQC. A mechanism of formation pathway for Imp-7 was proposed. Optimum separation for OLN and eight related impurities was carried out on an Agilent Octyldecyl silica column (TC-C(18), 4.6 mm × 250 mm, 5 μm) using a gradient HPLC method. The method was validated with respect to specificity, linearity, accuracy, precision, LOD and LOQ. Regression analysis showed good correlation (r(2) > 0.9985) between the investigated component concentrations and their peak areas within the test ranges for OLN and eight impurities. The repeatability and intermediate precision, expressed as RSD, were less than 1.74%. The proposed stability-indicating method was suitable for routine quality control and drug analysis of OLN in bulk drugs.

  13. Development and validation of a stability-indicating RP-HPLC method for simultaneous assay of betamethasone dipropionate, chlorocresol, and for the estimation of betamethasone dipropionate related compounds in a pharmaceutical cream and ointment.

    PubMed

    Johnston, Stephen E; Gill, Nicole L; Wei, Yu-Chien; Markovich, Robert; Rustum, Abu M

    2010-10-01

    A new stability-indicating reversed-phase HPLC (RP-HPLC) method has been developed and validated for simultaneous assay of betamethasone dipropionate (BD) and chlorocresol and also for the estimation of BD related compounds in a pharmaceutical cream matrix. In addition, this newly developed RP-HPLC method was also demonstrated as suitable for a pharmaceutical ointment product that does not contain chlorocresol. The RP-HPLC method uses a Waters SymmetryShield RP18 analytical column (150 × 4.6 mm). Water (mobile phase A) and acetonitrile (mobile phase B) were used in the gradient elution with a flow rate of 1.5 mL/min and detection wavelength at 240 nm. A Waters XBridge Shield RP18 analytical column (150 × 4.6 mm) was identified as an alternate column. The limit of detection (LOD) and the limit of quantitation (LOQ) are 0.02 μg/mL and 0.05 μg/mL, respectively. The precision of the method for BD is less than 0.3% RSD, and the accuracy of BD ranged from 99.5% to 102.6%. The stability-indicating capability of this method has been demonstrated by analyzing aged samples of the product. This RP-HPLC method was successfully validated per ICH guidelines and proved to be suitable for routine quality control use.

  14. A validated specific stability-indicating RP-HPLC assay method for Ambrisentan and its related substances.

    PubMed

    Narayana, M B V; Chandrasekhar, K B; Rao, B M

    2014-09-01

    A validated specific stability-indicating reverse-phase liquid chromatographic method was developed for the quantitative determination of Ambrisentan as well as its related substances in bulk samples, pharmaceutical dosage forms in the presence of degradation products and its related impurities. Forced degradation studies were performed on bulk samples of Ambrisentan as per the ICH-prescribed stress conditions using acid, base, oxidative, thermal stress and photolytic degradation to show the stability-indicating power of the LC method. Significant degradation in acidic, basic stress conditions was observed and no degradation was observed in other stress conditions. The chromatographic method was optimized using the samples generated from the forced degradation studies and the impurity-spiked solution. Good resolution between the peaks corresponds to Ambrisentan-related impurities and degradation products from the analyte were achieved on a SunFire C18 column using a mobile phase consisting of a mixture of potassium dihydrogen orthophosphate at a pH adjusted to 2.5 with ortho-phosphoric acid in water and a mixture of acetonitrile:methanol using a simple linear gradient. The detection was carried out at 225 nm. The limit of detection and the limit of quantification for the Ambrisentan and its related impurities were established. The stressed test solutions were assayed against the qualified working standard of Ambrisentan and the mass balance in each case was between 98.9 and 100.3%, indicating that the developed LC method was stability indicating. Validation of the developed LC method was carried out as per the ICH requirements. The developed method was found to be suitable to check the quality of bulk samples of Ambrisentan at the time of batch release and also during its storage (long-term and accelerated stability).

  15. Stability-indicating RP-HPLC Method for the Simultaneous Determination of Sitagliptin and Simvastatin in Tablets

    PubMed Central

    Ramalingam, P.; Bhaskar, V. Udaya; Reddy, Y. Padmanabha; Kumar, K. Vinod

    2014-01-01

    A new stability-indicating high-performance liquid chromatographic method for simultaneous analysis of sitagliptin and simvastatin in pharmaceutical dosage form was developed and validated. The mobile phase consisted of methanol and water (70:30, v/v) with 0.2 % of n-heptane sulfonic acid adjusted to pH 3.0 with ortho phosphoric acid was used. Retentions of sitagliptin and simvastatin were 4.3 min and 30.4 min, respectively with a flow rate of 1 ml/min on C8 (Qualisil BDS, 250×4.6 mm, 5 μ). Eluents were detected at 253 nm using photodiode diode array detector. The linear regression analysis data for the linearity plot showed correlation coefficient values of 0.9998 and 0.9993 for sitagliptin and simvastatin, with respective concentration ranges of 20-150 μg/ml and 8-60 μg/ml. The relative standard deviation for inter-day precision was lower than 2.0%. The assay of sitagliptin and simvastatin was determined in tablet dosage form was found to be within limits. Both drugs were subjected to a variety of stress conditions such as acidic, basic, oxidation, photolytic, neutral and thermal stress in order to achieve adequate degradation. Results revealed that considerable degradation was found in all stress conditions except oxidative degradations. The method has proven specificity for stability indicating assay method. PMID:25425754

  16. Development and validation of a stability indicating RP-HPLC method for the simultaneous determination of related substances of albuterol sulfate and ipratropium bromide in nasal solution.

    PubMed

    Kasawar, Gajanan B; Farooqui, Mazahar

    2010-05-01

    A simple, sensitive and specific RP-HPLC method was developed for the quantification of related impurities of albuterol sulfate (AS) and ipratropium bromide (IB) in liquid pharmaceutical dosage form. The chromatographic separation employs gradient elution using an inertsil C8-3, 250mmx4.6mm, 5mum columns. Mobile phase consisting of solvent A (solution containing 2.5g of potassium dihydrogen phosphate and 2.87g of heptane-1-sulfonic acid sodium salt per liter of water, adjusted to pH 4 with orthophosphoric acid) and solvent B (acetonitrile) delivered at a flow rate of 1.0mlmin(-1). The analytes were detected and quantified at 210nm using photodiode array (PDA) detector. The method was validated as per ICH guidelines, demonstrating to be accurate and precise (repeatability and intermediate precision level) within the corresponding linear range of known impurities of AS and IB. The specificity of the method was investigated under different stress conditions including hydrolytic, oxidative, photolytic and thermal as recommended by ICH guidelines. Relevant degradation was found to take place under hydrolytic and oxidative conditions. Robustness against small modification in pH, column oven temperature, flow rate and percentage of the mobile phase composition was ascertained. Lower limit of quantification and detection were also determined. The peak purity indices (purity anglestability indicating capability of the method.

  17. Development and Validation of a Stability-Indicating RP-HPLC Method for the Estimation of Drotaverine Impurities in API and Pharmaceutical Formulation

    PubMed Central

    Thummala, Veera Raghava Raju; Tharlapu, Satya Sankarsana Jagan Mohan; Rekulapalli, Vijay Kumar; Ivaturi, Mrutyunjaya Rao; Nittala, Someswara Rao

    2014-01-01

    A sensitive, stability-indicating gradient RP-HPLC method with PDA detection has been developed for the simultaneous analysis of drotaverine impurities in active pharmaceutical ingredient (API) and pharmaceutical formulations. Efficient chromatographic separation was achieved on an XTerra RP18, 150 × 4.6 mm, 5 μm column using gradient elution at 230 nm detection wavelength. The optimized mobile phase consisted of a 0.02 M potassium dihydrogen orthophosphate buffer of pH 3.0 as solvent A and acetonitrile as solvent B. The flow rate of the mobile phase was 1.0 mL min−1 with a column temperature of 25°C. The method showed linearity over the range of 0.251–10.033 μg/mL, 0.231–9.995 μg/mL, 0.230–10.089 μg/mL, 0.334–10.011 μg/mL, and 0.324–10.050 μg/mL for impurities 1, 2, 3, 4, and drotaverine, respectively, with a correlation coefficient greater than 0.999. The relative retention times and relative response factors of impurities 1, 2, 3, 4 were 0.36, 0.90, 1.42, 1.55 and 1.04, 0.84, 1.10, 1.30, respectively. The drotaverine formulation sample was subjected to the stress conditions of acid, base, oxidative, thermal, humidity, and photolytic degradation. Drotaverine was found to degrade significantly in peroxide, base, and heat stress conditions. The degradation products were well-resolved from drotaverine and its impurities. The peak purity test results confirmed that the drotaverine peak was homogenous and pure in all stress samples and the mass balance was found to be more than 98%, thus proving the stability-indicating power of the method. The developed method was validated according to ICH guidelines with respect to specificity, linearity, limit of detection and quantification, accuracy, precision, and robustness. PMID:24634845

  18. Development and Validation of a Stability-Indicating RP-HPLC Method for the Estimation of Drotaverine Impurities in API and Pharmaceutical Formulation.

    PubMed

    Thummala, Veera Raghava Raju; Tharlapu, Satya Sankarsana Jagan Mohan; Rekulapalli, Vijay Kumar; Ivaturi, Mrutyunjaya Rao; Nittala, Someswara Rao

    2014-01-01

    A sensitive, stability-indicating gradient RP-HPLC method with PDA detection has been developed for the simultaneous analysis of drotaverine impurities in active pharmaceutical ingredient (API) and pharmaceutical formulations. Efficient chromatographic separation was achieved on an XTerra RP18, 150 × 4.6 mm, 5 μm column using gradient elution at 230 nm detection wavelength. The optimized mobile phase consisted of a 0.02 M potassium dihydrogen orthophosphate buffer of pH 3.0 as solvent A and acetonitrile as solvent B. The flow rate of the mobile phase was 1.0 mL min(-1) with a column temperature of 25°C. The method showed linearity over the range of 0.251-10.033 μg/mL, 0.231-9.995 μg/mL, 0.230-10.089 μg/mL, 0.334-10.011 μg/mL, and 0.324-10.050 μg/mL for impurities 1, 2, 3, 4, and drotaverine, respectively, with a correlation coefficient greater than 0.999. The relative retention times and relative response factors of impurities 1, 2, 3, 4 were 0.36, 0.90, 1.42, 1.55 and 1.04, 0.84, 1.10, 1.30, respectively. The drotaverine formulation sample was subjected to the stress conditions of acid, base, oxidative, thermal, humidity, and photolytic degradation. Drotaverine was found to degrade significantly in peroxide, base, and heat stress conditions. The degradation products were well-resolved from drotaverine and its impurities. The peak purity test results confirmed that the drotaverine peak was homogenous and pure in all stress samples and the mass balance was found to be more than 98%, thus proving the stability-indicating power of the method. The developed method was validated according to ICH guidelines with respect to specificity, linearity, limit of detection and quantification, accuracy, precision, and robustness.

  19. New Validated Stability-Indicating Rp-HPLC Method for Simultaneous Estimation of Atorvastatin and Ezetimibe in Human Plasma by Using PDA Detector

    PubMed Central

    Kumar, S. Ashutosh; Debnath, Manidipa; Rao, J.V.L.N. Seshagiri; Sankar, D. Gowri

    2015-01-01

    Purpose: This paper describes a simple, precise and accurate RP-HPLC method for simultaneous estimation of atorvastatin and ezetimibe in plasma. Methods: The chromatographic separation of the drugs were performed on an X-Terra C8 (4.6 x 150 mm, 3.5 mm), with phosphate buffer [pH 3.5 with Ortho Phosphoric Acid] – acetonitrile 40:60 (v/v) as mobile phase. The detection was performed at 235 nm. The flow rate was maintained at 1.2 mL/min. The run time was 8.0 min. Results: The accuracy and reliability of the method was assessed by evaluation of linearity (5-25 µg/mL for both atorvastatin calcium and ezetimibe), precision (intra-day RSD 0.57 % and inter-day RSD 0.02 % for atorvastatin calcium and intra-day RSD 0.56 % and inter-day RSD 0.1 % for ezetimibe), accuracy (100.08- 100.84 % for atorvastatin calcium and 100.56- 101.00 % for ezetimibe), and specificity, in accordance with ICH guidelines. The LLOQ obtained by the proposed method were 1.294 and 1.384 µg/mL for atorvastatin and ezetimibe respectively. Conclusion: Overall the proposed method was found to be suitable and accurate for the quantitative determination in plasma. The method was effectively separated the drug from plasma. PMID:26504761

  20. Development and Validation of a Stability-Indicating RP-HPLC Method for the Simultaneous Determination of Phenoxyethanol, Methylparaben, Propylparaben, Mometasone Furoate, and Tazarotene in Topical Pharmaceutical Dosage Formulation

    PubMed Central

    Roy, Chinmoy; Chakrabarty, Jitamanyu

    2013-01-01

    A stability-indicating RP-HPLC method has been developed and validated for the simultaneous determination of phenoxyethanol (PE), methylparaben (MP), propylparaben (PP), mometasone furoate (MF), and tazarotene (TA) in topical pharmaceutical dosage formulation. The desired chromatographic separation was achieved on the Waters X-Bridge™ C18 (50×4.6mm, 3.5μ) column using gradient elution at 256 nm detection wavelength. The optimized mobile phase consisted of 0.1%v/v orthophosphoric acid in water as solvent-A and acetonitrile as solvent-B. The method showed linearity over the range of 5.88–61.76 μg/mL, 0.18–62.36 μg/mL, 0.17–6.26 μg/mL, 0.47–31.22 μg/mL, and 0.44–30.45 μg/mL for PE, MP, PP, MF, and TA, respectively. The recovery for all of the components was in the range of 98–102%. The stability-indicating capability of the developed method was established by analysing the forced degradation samples, in which the spectral purity of PE, MP, PP, MF, and TA along with the separation of degradation products from the analyte peaks was achieved. The proposed method was successfully applied for the quantitative determination of PE, MP, PP, MF, and TA in a cream sample. PMID:24482766

  1. A validated stability-indicating RP-HPLC method for levofloxacin in the presence of degradation products, its process related impurities and identification of oxidative degradant.

    PubMed

    Lalitha Devi, M; Chandrasekhar, K B

    2009-12-05

    The objective of current study was to develop a validated specific stability indicating reversed-phase liquid chromatographic method for the quantitative determination of levofloxacin as well as its related substances determination in bulk samples, pharmaceutical dosage forms in the presence of degradation products and its process related impurities. Forced degradation studies were performed on bulk sample of levofloxacin as per ICH prescribed stress conditions using acid, base, oxidative, water hydrolysis, thermal stress and photolytic degradation to show the stability indicating power of the method. Significant degradation was observed during oxidative stress and the degradation product formed was identified by LCMS/MS, slight degradation in acidic stress and no degradation was observed in other stress conditions. The chromatographic method was optimized using the samples generated from forced degradation studies and the impurity spiked solution. Good resolution between the peaks corresponds to process related impurities and degradation products from the analyte were achieved on ACE C18 column using the mobile phase consists a mixture of 0.5% (v/v) triethyl amine in sodium dihydrogen orthophosphate dihydrate (25 mM; pH 6.0) and methanol using a simple linear gradient. The detection was carried out at 294 nm. The limit of detection and the limit of quantitation for the levofloxacin and its process related impurities were established. The stressed test solutions were assayed against the qualified working standard of levofloxacin and the mass balance in each case was in between 99.4 and 99.8% indicating that the developed LC method was stability indicating. Validation of the developed LC method was carried out as per ICH requirements. The developed LC method was found to be suitable to check the quality of bulk samples of levofloxacin at the time of batch release and also during its stability studies (long term and accelerated stability).

  2. Development and validation of a RP-HPLC method for stability-indicating assay of gemifloxacin mesylate including identification of related substances by LC-ESI-MS/MS, 1H and 13C NMR spectroscopy.

    PubMed

    Rao, R Nageswara; Naidu, Ch Gangu; Prasad, K Guru; Narasimha, R

    2011-11-01

    A validated stability indicating RP-HPLC assay of gemifloxacin mesylate was developed by separating its related substances on an Inertsil-ODS3V-C18 (4.6 × 250 mm; 5 μm) column using 0.1% trifluoroaceticacid (pH 2.5) and methanol as a mobile phase in a gradient elution mode at a flow rate of 1.0 mL/min at 27°C. The column effluents were monitored by a photodiode array detector set at 287 nm. The method was validated in terms of accuracy, precision and linearity as per ICH guidelines. Forced degradation of gemifloxacin (GFX) was carried out under acidic, basic, thermal, photolysis and peroxide conditions and the degradation products were separated and characterized by ESI-MS/MS, (1) H and (13) C NMR spectroscopy. The method was successfully applied to the analysis of bulk drugs and the recoveries of gemifloxacin and impurities were in the range of 97.60-102.90 and 96.99-102.10%, respectively. No previous reports were found in the literature on identification of degradation products of gemifloxacin.

  3. Validated Stability-Indicating RP-HPLC Method for the Estimation of Degradation Behaviour of Organic Peroxide and Third-Generation Synthetic Retinoids in Topical Pharmaceutical Dosage Formulation.

    PubMed

    Roy, Chinmoy; Panigrahi, Lalatendu; Chakrabarty, Jitamanyu

    2015-01-01

    The objective of the current study was to establish a validated stability-indicating, high-performance liquid chromatographic method to determine the purity of benzoyl peroxide (BPO) and adapalene (ADP) in the presence of its impurities, forced degradation products, and placebo in pharmaceutical dosage forms. The desired chromatographic separation was achieved on the Kinetex(™) C18 (250 × 4.6 mm, 5 µm) column using gradient elution at 272 nm detection wavelength. The optimized mobile phase consisted of solvent A (mixture of 0.1% v/v glacial acetic acid in water and acetonitrile in the ratio of 80:20 v/v, respectively) and solvent B (mixture of acetonitrile: tetrahydrofuran: methanol in the ratio of 50:30:20 v/v/v, respectively). The stability-indicating capability of the developed method was established by analysing forced degradation samples in which the spectral purity of BPO and ADP along with separation of all degradation products from the analyte peaks was achieved. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision, and robustness.

  4. Validated Stability-Indicating RP-HPLC Method for the Estimation of Degradation Behaviour of Organic Peroxide and Third-Generation Synthetic Retinoids in Topical Pharmaceutical Dosage Formulation

    PubMed Central

    Roy, Chinmoy; Panigrahi, Lalatendu; Chakrabarty, Jitamanyu

    2015-01-01

    The objective of the current study was to establish a validated stability-indicating, high-performance liquid chromatographic method to determine the purity of benzoyl peroxide (BPO) and adapalene (ADP) in the presence of its impurities, forced degradation products, and placebo in pharmaceutical dosage forms. The desired chromatographic separation was achieved on the Kinetex™ C18 (250 × 4.6 mm, 5 µm) column using gradient elution at 272 nm detection wavelength. The optimized mobile phase consisted of solvent A (mixture of 0.1% v/v glacial acetic acid in water and acetonitrile in the ratio of 80:20 v/v, respectively) and solvent B (mixture of acetonitrile: tetrahydrofuran: methanol in the ratio of 50:30:20 v/v/v, respectively). The stability-indicating capability of the developed method was established by analysing forced degradation samples in which the spectral purity of BPO and ADP along with separation of all degradation products from the analyte peaks was achieved. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision, and robustness. PMID:26839821

  5. Method Development and Validation of a Stability-Indicating RP-HPLC Method for the Quantitative Analysis of Dronedarone Hydrochloride in Pharmaceutical Tablets

    PubMed Central

    Dabhi, Batuk; Jadeja, Yashwantsinh; Patel, Madhavi; Jebaliya, Hetal; Karia, Denish; Shah, Anamik

    2013-01-01

    A simple, precise, and accurate HPLC method has been developed and validated for the quantitative analysis of Dronedarone Hydrochloride in tablet form. An isocratic separation was achieved using a Waters Symmetry C8 (100 × 4.6 mm), 5 μm particle size column with a flow rate of 1 ml/min and UV detector at 290 nm. The mobile phase consisted of buffer: methanol (40:60 v/v) (buffer: 50 mM KH2PO4 + 1 ml triethylamine in 1 liter water, pH=2.5 adjusted with ortho-phosphoric acid). The method was validated for specificity, linearity, precision, accuracy, robustness, and solution stability. The specificity of the method was determined by assessing interference from the placebo and by stress testing the drug (forced degradation). The method was linear over the concentration range 20–80 μg/ml (r2 = 0.999) with a Limit of Detection (LOD) and Limit of Quantitation (LOQ) of 0.1 and 0.3 μg/ml respectively. The accuracy of the method was between 99.2–100.5%. The method was found to be robust and suitable for the quantitative analysis of Dronedarone Hydrochloride in a tablet formulation. Degradation products resulting from the stress studies did not interfere with the detection of Dronedarone Hydrochloride so the assay is thus stability-indicating. PMID:23641332

  6. Stability indicating RP-HPLC method development and validation for the simultaneous determination of aminexil and minoxidil in pharmaceutical dosage form.

    PubMed

    Siddiraju, S; Sahithi, M

    2015-03-01

    The objective of the present work is to develop stability indicating high-performance liquid chromatographic method for the simultaneous determination of aminexil and minoxidil in pharmaceutical dosage form. The chromatographic separation was achieved with BDS Hypersil C18 column (250 mm×4.6 mm×5 μ) as stationary phase and phosphate buffer and acetonitrile (78:22) as mobile phase. The method was employed by using a flow rate of 1.1 mL/min kept at 30°C. The detection wavelength was kept at 238 nm by using photo-diode array detector. The retention times of the aminexil and minoxidil were found to be 2.3 min and 3.9 min, respectively. The method developed was validated in accordance with ICH guidelines with respect to the stability indicating capacity of the method including system suitability, accuracy, precision, linearity, range, limit of detection, limit of quantification and robustness. The linearity responses of aminexil and minoxidil were found to be in the concentration ranges of 18.75-112.5 μg/mL and 25-150 μg/mL, respectively. The LOD and LOQ values for aminexil were found to be 0.31 and 0.92 μg/mL and minoxidil were found to be 0.03 and 0.10 μg/mL respectively. The percentage recoveries for both the drugs were found in the range of 98-101%. This method is accurate, precise and sensitive; hence, it can be employed for routine quality control of aminexil and minoxidil in pharmaceutical industries and drug testing laboratories.

  7. LC-MS-MS Characterization of Forced Degradation Products of Fidarestat, a Novel Aldose Reductase Inhibitor: Development and Validation of a Stability-Indicating RP-HPLC Method.

    PubMed

    Talluri, M V N Kumar; Khatoon, Lubna; Kalariya, Pradipbhai D; Chavan, Balasaheb B; Ragampeta, Srinivas

    2015-10-01

    An accurate, precise, robust and selective stability-indicating liquid chromatographic (LC) method has been developed for the monitoring of fidarestat in the presence of its forced degradants. The drug was subjected to hydrolysis (acid, alkali and neutral degradation), oxidation, photolysis and thermal stress conditions. The drug degraded significantly under hydrolytic (basic, acidic and neutral) and oxidative stress conditions, whereas it was found to be stable in photolytic and thermal conditions. The chromatographic separation was achieved on a Grace C18, (250 mm × 4.6 mm × 5 μm) column using gradient mobile phase system consisting of 10 mM of ammonium acetate buffer at pH 4 and acetonitrile at a flow rate of 1 mL/min with UV detection at 283 nm. The developed method was extended to liquid chromatography quadrupole time-of-flight tandem mass spectrometry (LC-QTOF-MS-MS) for characterization of all the degradation products. A total of five new degradation products were identified and characterized by LC-QTOF-MS-MS. The developed LC method was validated as per ICH guideline Q2 (R1). The proposed method was found to be successively applied for the quality control of fidarestat in bulk drug analysis.

  8. Development and validation of stability indicating the RP-HPLC method for the estimation of related compounds of guaifenesin in pharmaceutical dosage forms

    PubMed Central

    Reddy, Sunil Pingili; Babu, K. Sudhakar; Kumar, Navneet; Sekhar, Y. V. V. Sasi

    2011-01-01

    Aim and background: A stability-indicating gradient reverse phase liquid chromatographic (RP-LC) method was developed for the quantitative determination of related substances of guaifenesin in pharmaceutical formulations. Materials and methods: The baseline separation for guaifenesin and all impurities was achieved by utilizing a Water Symmetry C18 (150 mm × 4.6 mm) 5 μm column particle size and a gradient elution method. The mobile phase A contains a mixture of 0.02 M KH2PO4 (pH 3.2) and methanol in the ratio of 90:10 v/v, while the mobile phase B contains 0.02 M KH2PO4 (pH 3.2) and methanol in the ratio of 10:90 v/v, respectively. The flow rate of the mobile phase was 0.8 ml/min with a column temperature of 25°C and detection wavelength at 273 nm. Results: Guaifenesin was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal, and photolytic degradation. Conclusion: The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection and quantification, accuracy, precision, and robustness. PMID:23781462

  9. Stability-Indicating RP-HPLC Methods for the Determination of Fluorometholone in Its Mixtures with Sodium Cromoglycate and Tetrahydrozoline Hydrochloride.

    PubMed

    El-Bagary, Ramzia I; Fouad, Marwa A; El-Shal, Manal A; Tolba, Enas H

    2016-07-01

    Two stability-indicating reversed-phase liquid chromatographic methods were developed and validated for the determination of fluorometholone (FLU) in its mixtures with sodium cromoglycate (SCG) and tetrahydrozoline hydrochloride (THZ). The first HPLC method (Method 1) was based on isocratic elution of FLU and SCG along with their alkaline degradation products on a reversed phase C18 column (250 × 4.6 mm id)-ACE Generix 5, using a mobile phase consisting of methanol-water (70 : 30, v/v), pH adjusted to 2.5 using orthophosphoric acid at a flow rate of 1.2 mL min(-1) Quantitation was achieved with UV detection at 240 nm. The second HPLC method (Method 2) was based on isocratic elution of FLU, its alkaline degradation product and THZ on a reversed phase C8 column (250 × 4.6 mm)-ACE Generix 5, using a mobile phase consisting of acetonitrile-50 mM potassium dihydrogen orthophosphate (40 : 60, v/v) at a flow rate of 2 mL min(-1) Quantitation was achieved by applying dual-wavelength detection, where FLU and its alkaline degradation product were detected at 240 nm and THZ was detected at 215 nm at ambient temperatures. Linearity, accuracy and precision were found to be acceptable over the concentration range of 5-50 and 10-500 μg mL(-1) for FLU and SCG (Method 1) and over the concentration range of 5-80 and 5-60 μg mL(-1) for FLU and THZ (Method 2), respectively. Besides, the FLU alkaline degradation product was verified using IR, NMR and LC-MS spectroscopy. The two proposed methods could be successfully applied for the routine analysis of the studied drugs either in their pure bulk powders or in their pharmaceutical preparations without any preliminary separation step.

  10. Quality by Design-Based Development of a Stability-Indicating RP-HPLC Method for the Simultaneous Determination of Methylparaben, Propylparaben, Diethylamino Hydroxybenzoyl Hexyl Benzoate, and Octinoxate in Topical Pharmaceutical Formulation

    PubMed Central

    Roy, Chinmoy; Chakrabarty, Jitamanyu

    2014-01-01

    Abstract A stability-indicating RP-HPLC method has been developed and validated for the simultaneous determination of methylparaben (MP), propylparaben (PP), diethylamino hydroxybenzoyl hexyl benzoate (DAHHB), and octinoxate (OCT) in topical pharmaceutical formulation. The desired chromatographic separation was achieved on the KinetexTM C18 (250 × 4.6 mm, 5 μm) column using gradient elution at 257 nm detection wavelength. The optimized mobile phase consisted of a buffer : acetonitrile : tetrahydrofuran (60 : 30 : 10, v/v/v) as solvent A and acetonitrile : tetrahydrofuran (70 : 30, v/v) as solvent B. The method showed linearity over the range of 0.19–148.4 μg/mL, 0.23–15.3 μg/mL, 1.97–600.5 μg/mL, and 1.85–451.5 μg/mL for MP, PP, DAHHB, and OCT, respectively. Recovery for all the components was found to be in the range of 98–102%. The stability-indicating capability of the developed method was established by analysing the forced degradation samples in which the spectral purity of MP, PP, DAHHB, and OCT, along with the separation of the degradation products from the analyte peaks, was achieved. The proposed method was successfully applied for the quantitative determination of MP, PP, DAHHB, and OCT in the lotion sample. The design expert with ANOVA software with the linear model was applied and a 24 full factorial design was employed to estimate the model coefficients and also to check the robustness of the method. Results of the two-level full factorial design, 24 with 20 runs including four centrepoint analysis based on the variance analysis (ANOVA), demonstrated that all four factors, as well as the interactions of resolution between DAHHB and OCT are statistically significant. PMID:25853065

  11. Development and Validation of Stability-Indicating RP-HPLC Method for Simultaneous Determination of Metformin HCl and Glimepiride in Fixed-Dose Combination.

    PubMed

    Vaingankar, Pradnya N; Amin, Purnima D

    2016-01-01

    A simple reversed-phase high-performance liquid chromatography method was developed and validated for simultaneous determination of Metformin hydrochloride (MET) and Glimepiride (GLM) in combination and estimation of their principal degradation products. The separation was achieved using JASCO Finepak SIL (250 mm × 4.6 mm i.d. 5 μm) at ambient temperature. The optimized mobile phase composed of an aqueous phase (20 mM phosphate buffer, adjusted to pH 3.0) and an organic phase (methanol:acetonitrile; 62.5:37.5) in the ratio of 80:20. The flow rate was 1 mL/minute, and the analytes were detected at 230 nm. The developed method was validated for accuracy, precision, specificity, linearity, and sensitivity. The chromatographic analysis time was approximately six minutes with the complete resolution of MET (Rt = 2.75 minutes) and GLM (Rt = 5.87 minutes). The method exhibited good linearity over the range of 5-30 μg/mL for MET and 1-10 μg/mL for GLM. The drugs in combination were subjected to various stress degradation studies as per the International Conference Harmonization (ICH) guidelines. Results obtained from the stress degradation studies revealed that the developed method is applicable for stability studies.

  12. Development and Validation of Stability-Indicating RP-HPLC Method for Simultaneous Determination of Metformin HCl and Glimepiride in Fixed-Dose Combination

    PubMed Central

    Vaingankar, Pradnya N.; Amin, Purnima D.

    2016-01-01

    A simple reversed-phase high-performance liquid chromatography method was developed and validated for simultaneous determination of Metformin hydrochloride (MET) and Glimepiride (GLM) in combination and estimation of their principal degradation products. The separation was achieved using JASCO Finepak SIL (250 mm × 4.6 mm i.d. 5 μm) at ambient temperature. The optimized mobile phase composed of an aqueous phase (20 mM phosphate buffer, adjusted to pH 3.0) and an organic phase (methanol:acetonitrile; 62.5:37.5) in the ratio of 80:20. The flow rate was 1 mL/minute, and the analytes were detected at 230 nm. The developed method was validated for accuracy, precision, specificity, linearity, and sensitivity. The chromatographic analysis time was approximately six minutes with the complete resolution of MET (Rt = 2.75 minutes) and GLM (Rt = 5.87 minutes). The method exhibited good linearity over the range of 5–30 μg/mL for MET and 1–10 μg/mL for GLM. The drugs in combination were subjected to various stress degradation studies as per the International Conference Harmonization (ICH) guidelines. Results obtained from the stress degradation studies revealed that the developed method is applicable for stability studies. PMID:26997866

  13. Highly efficient, selective, sensitive and stability indicating RP-HPLC-UV method for the quantitative determination of potential impurities and characterization of four novel impurities in eslicarbazepine acetate active pharmaceutical ingredient by LC/ESI-IT/MS/MS.

    PubMed

    Thomas, Saji; Bharti, Amber; Maddhesia, Pawan Kumar; Shandilya, Sanjeev; Agarwal, Ashutosh; Dharamvir; Biswas, Sujay; Bhansal, Vikas; Gupta, Ashish Kumar; Tewari, Praveen Kumar; Mathela, Chandra S

    2012-03-05

    A novel, sensitive, selective and stability indicating LC-UV method was developed for the determination of potential impurities of eslicarbazepine acetate. High performance liquid chromatographic investigation of eslicarbazepine acetate laboratory sample revealed the presence of several impurities. Three impurities were characterized rapidly and four impurities were found to be unknown. The unknown impurities were identified by liquid chromatography coupled with electrospray ionization, ion trap mass spectrometry (LC/ESI-IT/MS/MS). Structural confirmation of these impurities was unambiguously carried out by synthesis followed by characterization using nuclear magnetic resonance spectroscopy (NMR), infrared spectroscopy (FT-IR) and mass spectrometry (MS). Based on the spectroscopic, spectrometric and elemental analysis data unknown impurities were characterized as 5-acetyl-5,11-dihydro-10H-dibenzo [b,f]azepin-10-one, N-acetyl-5H-dibenzo[b,f]azepine-5-carboxamide, 5-acetyl-10,11-dihydro-5H-dibenzo[b,f]azepin-10-yl acetate and 5-acetyl-5H-dibenzo[b,f]azepin-10-yl acetate. The newly developed LC-UV method was validated according to ICH guidelines considering eleven potential impurities and four new impurities to demonstrate specificity, precision, linearity, accuracy and stability indicating nature of the method. The newly developed method was found to be highly efficient, selective, sensitive and stability indicating. A plausible pathway for the formation of four new impurities is proposed.

  14. Identification and characterization of stress degradants of lacosamide by LC-MS and ESI-Q-TOF-MS/MS: development and validation of a stability indicating RP-HPLC method.

    PubMed

    Ramisetti, Nageswara Rao; Kuntamukkala, Ramakrishna; Lakshetti, Sridhar; Sripadi, Prabhakar

    2014-07-01

    The current study dealt with the degradation behavior of lacosamide (LAC) under ICH prescribed stress conditions. LAC was found to be labile under acid and base hydrolytic stress conditions, while it was stable to neutral hydrolytic, oxidative, photolytic and thermal stress. In total, seven degradation products (DPs) were formed, which were separated on a C18 column using a stability-indicating method. LC-MS analyses indicated that one of the DPs had the same molecular mass as that of the drug. Structural characterization of DPs was carried out using ESI-Q-TOF-MS/MS technique. The degradation pathways and mechanisms of degradation of the drug were delineated by carrying out the degradation in different co-solvents viz. methanol, deuterated methanol, ethanol, 1-propanol and acetonitrile. The developed LC method was validated for the determination of related substances and assay of LAC as per ICH guidelines. This study demonstrates a comprehensive approach of LAC degradation studies during its development phase.

  15. Development and Validation of a Novel Stability-Indicating RP-HPLC Method for the Simultaneous Determination of Related Substances of Ketoprofen and Omeprazole in Combined Capsule Dosage Form.

    PubMed

    Koppala, Srinivasarao; Reddy, V Ranga; Anireddy, Jaya Shree

    2016-01-01

    A novel, simple, sensitive, selective and reproducible stability-indicating high performance liquid chromatographic method was developed for the quantitative determination of degradation products and process-related impurities of ketoprofen (KET) and omeprazole (OMZ) in combined oral solid dosage form. Chromatographic separation was achieved on a Phenomenex Luna C18 (2) column (150 × 4.6 mm, 5 μm) under gradient elution by using a binary mixture of potassium dihydrogen phosphate buffer and acetonitrile at a flow rate of 0.8 mL/min. Chromatogram was monitored at 233 nm for KET impurities and at 305 nm for OMZ impurities using a dual wavelength UV detector. Resolution for KET and OMZ and 14 impurities was found to be >1.5 for any pair of components. Typical retention behaviors of impurities at various pH values were depicted graphically. To prove the stability-indicating power of the method, the drug product was subjected to hydrolytic, oxidative, photolytic, humidity and thermal stress conditions as per ICH. The developed method was validated according to the current ICH guidelines for specificity, limit of detection, limit of quantification, linearity, accuracy, precision, ruggedness and robustness.

  16. Development and Validation of a Stability Indicating RP-HPLC Method for Hydrocortisone Acetate Active Ingredient, Propyl Parahydroxybenzoate and Methyl Parahydroxybenzoate Preservatives, Butylhydroxyanisole Antioxidant, and Their Degradation Products in a Rectal Gel Formulation.

    PubMed

    Ascaso, Magda; Pérez-Lozano, Pilar; García, Mireia; García-Montoya, Encarna; Miñarro, Montse; Ticó, Josep R; Fàbregas, Anna; Carrillo, Carolina; Sarrate, Rocío; Suñé-Negre, Josep M

    2015-01-01

    A stability indicating method was established through a stress study, wherein different methods of degradation (oxidation, hydrolysis, photolysis, and temperature) were studied simultaneously to determine the active ingredient hydrocortisone acetate, preservatives propyl parahydroxybenzoate, and methyl parahydroxybenzoate, antioxidant butylhydroxyanisole (BHA), and their degradation products in a semisolid dosage gel form. The proposed method was suitably validated using a Zorbax SB-Phenyl column and gradient elution. The mobile phase consisted of a mixture of methanol, acetonitrile, and water in different proportions according to a planned program at a flow rate of 1.5 mL/min. The diode array detector was set at 240 nm for the active substance and two preservatives, and 290 nm for BHA. The validation study was conducted according to International Conference on Harmonization guidelines for specificity, linearity, repeatability, precision, and accuracy. The method was used for QC of hydrocortisone acetate gel and for the stability studies with the aim of quantifying the active substance, preservatives, antioxidant, and degradation products. It has proved to be suitable as a fast and reliable method for QC.

  17. Development and Validation of a Stability-Indicating RP-HPLC Method for the Determination of Process-Related Impurities and Degradation Products of Rabeprazole Sodium in Pharmaceutical Formulation.

    PubMed

    Kumar, Navneet; Sangeetha, Dhanaraj

    2013-01-01

    The objective of the current study was to develop and validate a reversed-phase high-performance liquid chromatographic method for the quantitative determination of process-related impurities and degradation products of rabeprazole sodium in pharmaceutical formulation. Chromatographic separation was achieved on the Waters Symmetry Shield RP18 (250 mm × 4.6 mm) 5 μm column with a mobile phase containing a gradient mixture of solvent A (mixture of 0.025 M KH2PO4 buffer and 0.1% triethylamine in water, pH 6.4 and acetonitrile in the ratio of 90:10 v/v, respectively) and solvent B (mixture of acetonitrile and water in the ratio of 90:10 v/v, respectively). The mobile phase was delivered at a flow rate of 1.0 mL/min and with UV detection at 280 nm. Rabeprazole sodium was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal, and photolytic degradation. Rabeprazole sodium was found to degrade significantly under acid hydrolysis, base hydrolysis, oxidative, and thermal degradation conditions. The degradation products were well-resolved from the main peak and its impurities, thus proving the stability-indicating power of the method. The mass balance was found to be in the range of 97.3-101.3% in all of the stressed conditions, thus proving the stability-indicating power of the method. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision, and robustness.

  18. Assessment of Lipophilicity Indices Derived from Retention Behavior of Antioxidant Compounds in RP-HPLC.

    PubMed

    Sima, Ioana Anamaria; Kot-Wasik, Agata; Wasik, Andrzej; Namieśnik, Jacek; Sârbu, Costel

    2017-03-29

    Reverse phase high pressure liquid chromatography was employed in order to evaluate the lipophilicity of antioxidant compounds from different classes, such as phenolic acids, flavanones, flavanols, flavones, anthocyanins, stilbenes, xantonoids, and proanthocyanidins. The retention time of each compound was measured using five different HPLC columns: RP18 (LiChroCART, Purosphere RP-18e), C8 (Zorbax, Eclipse XDBC8), C16-Amide (Discovery RP-Amide C16), CN100 (Saulentechnik, Lichrosphere), and pentafluorophenyl (Phenomenex, Kinetex PFP), and the mobile phase consisted of methanol and water (0.1% formic acid) in different proportions. The measurements were conducted at two different column temperatures, room temperature (22 °C) and, in order to mimic the environment from the human body, 37 °C. Furthermore, principal component analysis (PCA) was used to obtain new lipophilicity indices and holistic lipophilicity charts. Additionally, highly representative depictions of the chromatographic behavior of the investigated compounds and stationary phases at different temperatures were obtained using two new chemometric approaches, namely two-way joining cluster analysis and sum of ranking differences.

  19. An RP-HPLC-UV method with SPE for cefotaxime in all-in-one total parenteral nutritional admixtures: application to stability studies.

    PubMed

    Iqbal, Muhammad Shahid; Bahari, Mohd Baidi; Darwis, Yusrida; Iqbal, Muhammad Zahid; Hayat, Amer; Venkatesh, Gantala

    2013-01-01

    A simple and selective RP-HPLC-UV method with SPE was developed and validated for the quantification of cefotaxime in all-in-one total parenteral nutrition (AIO-TPN) admixtures. Chromatographic separation was achieved on a 5 pm particle size C18 DB column (250 x 4.6 mm id) using the mobile phase ammonium acetate (25 mM, pH 4.0)-50% acetonitrile in methanol (80 + 20, v/v). The flow rate was 0.9 mL/min and the detection wavelength was 254 nm. The analyte was extracted from AIO-TPN admixtures by means of an SPE method. The cefotaxime calibration curve was linear over a concentration range of 100-1400 microg/mL with a correlation coefficient of > or = 0.9994. The intraday accuracy and precision for cefotaxime were < or = -3.15 and < or = 3.08%, respectively, whereas the interday accuracy and precision were < or = -2.48 and < or = 2.25%, respectively. The method was successfully applied to stability studies of cefotaxime in the presence of micronutrients together with low and high concentrations of macronutrients in AIO-TPN admixtures. Cefotaxime was degraded by 13.00 and 26.05% at room temperature (25 +/- 2 degrees C) after 72 h in low and high macronutrient concentration formulations of AIO-TPN admixtures, respectively. The values of cefotaxime degradation rates for low and high macronutrient concentration formulations of AIO-TPN admixtures were -0.164 and -0.353, respectively. These results indicated that there was a higher rate of degradation in the AIO-TPN admixture formulations containing high concentrations of macronutrients.

  20. Stability indicating methods for the determination of some anti-fungal agents using densitometric and RP-HPLC methods.

    PubMed

    Mousa, Bahia Abbas; El-Kousy, Naglaa Mahmoud; El-Bagary, Ramzia Ismail; Mohamed, Nashwah Gadalla

    2008-02-01

    Two chromatographic methods were developed for the determination of some anti-fungal drugs in the presence of either their degradation products or cortisone derivatives. The densitometric method determined mixtures of each of ketoconazole (KT), clotrimazole (CL), miconazole nitrate (MN) and econazole nitrate (EN) with the degradation products of each one. Mixtures of MN with hydrocortisone (HC) and of EN with triamcinolone acetonide (TA) were also successfully separated and determined by this technique. For KT and CL, a mixture of methanol:water:triethylamine (70:28:2 v/v) was used as a developing system and the spots were scanned at 243 nm and 220 nm for KT and CL, respectively. For MN and EN, a mixture of hexane:isopropyl alcohol:triethylamine (80:17:3 v/v) was used as a developing system and the spots were scanned at 225 nm for both drugs. The HPLC method determined mixtures of CL or EN with their degradation products which were separated and quantified on a Zorbax C8 column. Elution was carried out using methanol:phosphate buffer pH 2.5 (65:35 v/v) as a mobile phase at a flow rate of 1.5 ml/min and UV detection at 220 nm for CL. For EN, a mixture of methanol:water containing 0.06 ml triethylamine pH 10 (75:25 v/v) was used as a mobile phase at a flow rate of 1.5 ml/min and UV detection at 225 nm. The methods were also used to separate mixtures of CL with betamethasone dipropionate (BD) and EN with TA in a laboratory prepared mixture and in pharmaceutical preparations. The methods were sensitive, precise and applicable for determination of the drugs in pharmaceutical dosage forms.

  1. Stability-Indicating RP-HPLC Method for the Simultaneous Determination of Prazosin, Terazosin, and Doxazosin in Pharmaceutical Formulations

    PubMed Central

    Shrivastava, Alankar; Gupta, Vipin B.

    2012-01-01

    The current study was carried out with an attempt to separate similarly structured title drugs by liquid chromatography. Spectrophotometric techniques were generally insufficient under these conditions because of the spectral overlapping of drugs with similar functional groups. The pharmaceutical drugs prazosin, terazosin, and doxazosin contain the same parent quinazoline nucleus, thus making it especially difficult to separate the former two drugs because of their very similar structures. A simple and sensitive method for the routine determination of these drugs in pharmaceutical formulations was attempted. We found that the mobile phase consisting of A: ACN–diethylamine (0.05 ml), B: methanol, and C: 10 mM Ammonium acetate separated these drugs effectively. Separations were carried out on a new Kromasil C18 column (250 × 4.6 mm, 5.0 μm) at 254 nm wavelength. The calibration curve was found to be linear in the range of 2–500 μg/ml. The stated method was then validated in terms of specificity, linearity, precision, and accuracy. Additionally, the proposed method reduced the duration of the analysis. PMID:23008810

  2. Stability-Indicating RP-HPLC Method for the Simultaneous Determination of Prazosin, Terazosin, and Doxazosin in Pharmaceutical Formulations.

    PubMed

    Shrivastava, Alankar; Gupta, Vipin B

    2012-01-01

    The current study was carried out with an attempt to separate similarly structured title drugs by liquid chromatography. Spectrophotometric techniques were generally insufficient under these conditions because of the spectral overlapping of drugs with similar functional groups. The pharmaceutical drugs prazosin, terazosin, and doxazosin contain the same parent quinazoline nucleus, thus making it especially difficult to separate the former two drugs because of their very similar structures. A simple and sensitive method for the routine determination of these drugs in pharmaceutical formulations was attempted. We found that the mobile phase consisting of A: ACN-diethylamine (0.05 ml), B: methanol, and C: 10 mM Ammonium acetate separated these drugs effectively. Separations were carried out on a new Kromasil C18 column (250 × 4.6 mm, 5.0 μm) at 254 nm wavelength. The calibration curve was found to be linear in the range of 2-500 μg/ml. The stated method was then validated in terms of specificity, linearity, precision, and accuracy. Additionally, the proposed method reduced the duration of the analysis.

  3. Forced degradation studies of clobetasol 17-propionate in methanol, propylene glycol, as bulk drug and cream formulations by RP-HPLC.

    PubMed

    Fauzee, Ayeshah Fateemah Beebee; Walker, Roderick Bryan

    2013-03-01

    A rapid, simple, stability-indicating forced degradation study of clobetasol 17-propionate was conducted using RP-HPLC. The method was used to analyze clobetasol 17-propionate in methanol, propylene glycol, and a cream formulation. Isocratic elution of clobetasol and its degradation products was achieved using a Nova-Pak® 4 μm C18 150 mm × 3.9 mm id cartridge column and a mobile phase of methanol: water (68:32 v/v) at a flow rate of 0.9 mL min(-1). Quantitation was achieved with UV detection at 239 nm. Nondegraded clobetasol was eluted at a retention time of 6.0 min. Clobetasol 17-propionate was subjected to different stress conditions viz., acidic, basic, heat, oxidation, light, and neutral hydrolysis. The greatest degradation occurred under strong base and oxidative conditions. Strong base-degraded clobetasol produced additional peaks at retention times of 1.8, 4.0, 5.0, and 8.0 min and clobetasol oxidation degradation peaks eluted at 2.2 and 24 min. Complete validation was performed for linearity, accuracy, and precision over the concentration range 0.15-15 μg mL(-1). All data were analyzed statistically and this RP-HPLC method proved to be accurate, precise, linear, and stability indicating for the quantitation of clobetasol 17-propionate in methanol, propylene glycol, and cream formulations.

  4. Development and validation of RP-HPLC method for estimation of Cefotaxime sodium in marketed formulations.

    PubMed

    Lalitha, N; Pai, Pn Sanjay

    2009-12-01

    A RP-HPLC assay method has been developed and validated for cefotaxime. An isocratic RP-HPLC was developed on a SS Wakosil II- C8 column (250 mm ˜4.6 mm i.d., 5 μm) utilizing a mobile phase of ammonium acetate buffer (pH 6.8) and acetonitrile (85:15 v/v) with UV detection at wavelength 252 nm at the flow rate 0 .8 ml/min. The proposed method was validated for sensitivity, selectivity, linearity, accuracy, precision, ruggedness, robustness and solution stability. The response of the drug was linear in the concentration range of 10-70 μg/ml. Limit of detection and Limit of quantification was found to be 0.3 μg/ml and 0.6 μg/ml respectively. The % recovery ranged within 97-102 %. Method, system, interday and intraday precision was found to be within the limits of acceptance criteria. Method was found to be rugged when analysis was carried out by different analyst. The method was found to be sensitive and efficient with 2216 theoretical plates, 0.1128 mm HETP and tailing factor 1. The method was suitable for the quality control of cefotaxime in injection formulations.

  5. Structural Analysis and Quantitative Determination of Clevidipine Butyrate Impurities Using an Advanced RP-HPLC Method.

    PubMed

    Zhou, Yuxia; Zhou, Fan; Yan, Fei; Yang, Feng; Yao, Yuxian; Zou, Qiaogen

    2016-03-01

    Eleven potential impurities, including process-related compounds and degradation products, have been analyzed by comprehensive studies on the manufacturing process of clevidipine butyrate. Possible formation mechanisms could also be devised. MS and NMR techniques have been used for the structural characterization of three previously unreported impurities (Imp-3, Imp-5 and Imp-11). To separate and quantify the potential impurities in a simultaneous fashion, an efficient and advanced RP-HPLC method has been developed. In doing so, four major degradation products (Imp-2, Imp-4, Imp-8 and Imp-10) can be observed under varying stress conditions. This analytical method has been validated according to ICH guidelines with respect to specificity, accuracy, linearity, robustness and stability. The method described has been demonstrated to be applicable in routine quality control processes and stability evaluation studies of clevidipine butyrate.

  6. Identification of Rhodiola species by using RP-HPLC*

    PubMed Central

    Wang, Qiang; Ruan, Xiao; Jin, Zhi-hua; Yan, Qi-chuan; Tu, Shan-jun

    2005-01-01

    An approach was established using RP-HPLC (reversed-phase high-performance liquid chromatography) to identify ten species of Rhodiola, R. coccinea A. Bor, R. junggarica C.Y. Yang et N.R. Cui spn., R. heterodonta A. Bor, R. linearifolia A. Bor, R. pamiro alaiucm A. Bor, R. kaschgarica A. Bor, R. litwinowii A. Bor, R. gelida schrenk, R. rosea L. and R. quadrifide Fisch et Mey collected from the Tianshan Mountains areas of China. Chromatograms of alcohol-soluble proteins, generated from these ten Rhodiola spp. were compared. Each chromatogram of alcohol-soluble proteins came from a single seed of one wild species only. The results showed that when using a Waters Delta Pak. C18, 5 μm particle size reversed phase column (150 mm×3.9 mm), a linear gradient of 22%–55% solvent B with a flow rate of 1 ml/min and a run time of 67 min, the chromatography gave optimum separation of Rhodiola alcohol-soluble proteins. Chromatogram of each species was different and could be used to identify those species. Cluster analysis of genetic similarity coefficients of 37% to 60% showed a medium degree of genetic diversity among the species in these eco-areas. Cluster analysis showed that the ten species of Rhodiola can be divided into four clusters and yielded the general and unique biochemical markers of these species. RP-HPLC was shown to be a rapid, repeatable and reliable method for Rhodiola species identification and analysis of genetic diversity. PMID:15909330

  7. Stability-Indicating TLC-Densitometric and HPLC Methods for the Simultaneous Determination of Piracetam and Vincamine in the Presence of Their Degradation Products.

    PubMed

    Ahmed, Amal B; Abdelrahman, Maha M; Abdelwahab, Nada S; Salama, Fathy M

    2016-11-01

    Newly established TLC-densitometric and RP-HPLC methods were developed and validated for the simultaneous determination of Piracetam (PIR) and Vincamine (VINC) in their pharmaceutical formulation and in the presence of PIR and VINC degradation products, PD and VD, respectively. The proposed TLC-densitometric method is based on the separation and quantitation of the studied components using a developing system that consists of chloroform-methanol-glacial acetic acid-triethylamine (8 + 2 + 0.1 + 0.1, v/v/v/v) on TLC silica gel 60 F254 plates, followed by densitometric scanning at 230 nm. On the other hand, the developed RP-HPLC method is based on the separation of the studied components using an isocratic elution of 0.05 M KH2PO4 (containing 0.1% triethylamine adjusted to pH 3 with orthophosphoric acid)-methanol (95 + 5, v/v) on a C8 column at a flow rate of 1 mL/min with diode-array detection at 230 nm. The developed methods were validated according to International Conference on Harmonization guidelines and demonstrated good accuracy and precision. Moreover, the developed TLC-densitometric and RP-HPLC methods are suitable as stability-indicating assay methods for the simultaneous determination of PD and VD either in bulk powder or pharmaceutical formulation. The results were statistically compared with those obtained by the reported RP-HPLC method using t- and F-tests.

  8. Intra-specific genetic relationship analyses of Elaeagnus angustifolia based on RP-HPLC biochemical markers.

    PubMed

    Wang, Qiang; Ruan, Xiao; Huang, Jun-hua; Xu, Ning-yi; Yan, Qi-chuan

    2006-04-01

    Elaeagnus angustifolia Linn. has various ecological, medicinal and economical uses. An approach was established using RP-HPLC (reversed-phase high-performance liquid chromatography) to classify and analyse the intra-specific genetic relationships of seventeen populations of E. angustifolia, collected from the Xinjiang areas of China. Chromatograms of alcohol-soluble proteins produced by seventeen populations of E. angustifolia, were compared. Each chromatogram of alcohol-soluble proteins came from a single seed of one wild plant only. The results showed that when using a Waters Delta Pak. C18, 5 microm particle size reversed phase column (150 mm x 3.9 mm), a linear gradient of 25%-60% solvent B with flow rate of 1 ml/min and run time of 67 min, the chromatography yielded optimum separation of E. angustifolia alcohol-soluble proteins. Representative peaks in each population were chosen according to peak area and occurrence in every seed. The converted data on the elution peaks of each population were different and could be used to represent those populations. GSC (genetic similarity coefficients) of 41% to 62% showed a medium degree of genetic diversity among the populations in these eco-areas. Cluster analysis showed that the seventeen populations of E. angustifolia could be divided into six clusters at the GSC=0.535 level and indicated the general and unique biochemical markers of these clusters. We suggest that E. angustifolia distribution in these eco-areas could be classified into six variable species. RP-HPLC was shown to be a rapid, repeatable and reliable method for E. angustifolia classification and identification and for analysis of genetic diversity.

  9. Development and validation of RP-HPLC method to determine anti-allergic compound in Thai traditional remedy called Benjalokawichien.

    PubMed

    Sakpakdeejaroen, Intouch; Juckmeta, Thana; Itharat, Arunporn

    2014-08-01

    Benjalokawichien (BLW) or Ya-Ha-Rak (HR) is a traditional remedy in the Nationaldrug list of herbal medicinal products AD 2012 of Thailand. For traditional use, BLW is used as antipyretic agent. It also has anti-allergic effect, particularly treating allergic rash. The ethanolic extract of BLW exhibited anti-allergic activity via inhibitory effect against a release ofbeta-hexosaminidase in RBL-2H3 cell line. Pectolinarigenin has been identified as the active compound ofBLW extract. In this study, a reversed-phase high performance liquid chromatography (RP-HPLC) method was developed in order to control quality ofpreparation in three aspects such as chemical fingerprint, quantification and stability of the ethanolic extract. The RP-HPLC was performed with a gradient mobile phase composed of 0.1% ortho phosphoric acid and acetronitrile, and peaks were detected at 331 nm. Based on validation results, this analytical method is precise, accurate and stable for quantitative determination ofpectolinarigenin. The amount ofpectolinarigenin in Benjalokawichien extract determined by this method was 18.50 mg/g ofextract. Therefore, this method could be consideredfor quality control ofBLWextract.

  10. Development and Validation of Miglitol and Its Impurities by RP-HPLC and Characterization Using Mass Spectrometry Techniques

    PubMed Central

    Balakumaran, Kesavan; Janagili, Mosesbabu; Rajana, Nagaraju; Papureddy, Sureshbabu; Anireddy, Jayashree

    2016-01-01

    Alpha glucoside inhibitors used to treat type-2 diabetes mellitus (DM) are likely to be safe and effective. These agents are most effective for postprandial hyperglycemia. Miglitol is a type of drug used to treat type-2 DM. A simple, selective, linear, precise and accurate reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for a related substance of miglitol and its identification, and characterization was done by different mass spectrometry techniques. The gradient method at a flow rate of 1.0 mL/min was employed on a prevail carbohydrate ES column (250 × 4.6 mm, 5 μm particle size) at a temperature of 35 °C. Mobile phase A consisted of 10 mM dipotassium hydrogen orthophosphate adjusted to pH 8.0 using concentrated phosphoric acid and mobile phase B consisted of acetonitrile. The ultraviolet detection wavelength was 210 nm and 20 μL of the sample were injected. The retention time for miglitol was about 24.0 min. Forced degradation of the miglitol sample was conducted in accordance with the International Conference on Harmonisation (ICH) guidelines. Acidic, basic, neutral, and oxidative hydrolysis, thermal stress, and photolytic degradation were used to assess the stability-indicating the power of the method. Substantial degradation was observed during oxidative hydrolysis. No degradation was observed under the other stress conditions. The method was optimized using samples generated by forced degradation and sample solutions spiked with impurities and epimers. Good resolution of the analyte peak from peaks, corresponding to process-related impurities, epimers and degradation products, was achieved and the method was validated as per the ICH guidelines. The method can successfully be applied for routine analysis of miglitol. PMID:27754407

  11. Analysis by RP-HPLC of mangiferin component correlation between medicinal loranthus and their mango host trees.

    PubMed

    Zhang, Xiejun; Su, Benwei; Li, Jing; Li, Yonghua; Lu, Dong; Zhu, Kaixin; Pei, Hehuan; Zhao, Minghui

    2014-01-01

    This study proposes a reversed-phase high-performance liquid chromatography (RP-HPLC) method for the determination of mangiferin in medicinal loranthus shrubs and their mango or non-mango host trees. Mangiferin in samples was extracted with a solution of 40% methanol. Analytical determination was conducted by RP-HPLC with ultraviolet detection at 258 nm. Chromatographic separation was achieved on an Inertsil ODS-SP column (250 × 4.6 mm, 5 µm) by isocratic elution with methanol-0.1% aqueous phosphoric acid (31:69, v/v). Mangiferin contents were 5.04 to 18.95 mg/g in mango trees and 0.44 to 3.72 mg/g in medicinal loranthus parasitized on mango host trees. Mangiferin could not be detected in non-mango trees and their loranthus shrubs. This study indicated that host trees could affect the quality of medicinal loranthus by transporting host-inherent components into loranthus.

  12. Isocratic RP-HPLC method for rutin determination in solid oral dosage forms.

    PubMed

    Kuntić, Vesna; Pejić, Natasa; Ivković, Branka; Vujić, Zorica; Ilić, Katarina; Mićić, Svetlana; Vukojević, Vladana

    2007-01-17

    A rapid and sensitive assay for quantitative determination of rutin in oral dosage forms based on isocratic reversed phase high performance liquid chromatography (RP-HPLC) was developed and validated. Using a C(18) reverse-phase analytical column, the following conditions were chosen as optimal: mobile phase methanol-water 1:1 (v/v), pH 2.8 (adjusted with phosphoric acid), flow rate=1 mL min(-1) and temperature T=40.0 degrees C. Linearity was observed in the concentration range 8-120 microg mL(-1) with a correlation coefficient of 0.99982 and the limit of detection (LOD)=2.6 microg mL(-1), and limit of quantification (LOQ)=8.0 microg mL(-1). Intra- and inter-day precision were within acceptable limits. Robustness test indicated that the mobile phase composition and pH influence mainly the separation. The proposed method allowed direct determination of rutin in pharmaceutical dosage forms in the presence of excipients, but is not suitable for preparations where compounds structurally/chemically related to rutin may be present.

  13. Use of ANN modelling in structure--retention relationships of diuretics in RP-HPLC.

    PubMed

    Agatonovic-Kustrin, S; Zecevic, M; Zivanovic, L

    1999-10-01

    Structure retention relationship study, conducted by RP HPLC, was used to investigate physical chemical parameters related to the RP retention times of amiloride, hydrochlorothiazide and methyldopa in order to predict the separation of amiloride and methylclothiazide from Lometazid tablets. Retention data were obtained with an ODS column using a mobile phase methanol water (pH adjusted with phosphoric acid). Physical chemical properties were calculated directly from the molecular structure. Artificial neural networks (ANNs) were used to correlate chromatograms retention times with mobile phase composition and pH, and with physical chemical properties of amiloride, hydrochlorothiazide and methyldopa and to predict separation of amiloride and methylclothiazide from Lometazid tablets. Sensitivity analysis was performed to interpret the meaning of the descriptors included in the models. Results confirmed the dominant role of the polar modifier in such chromatographic systems. Within a series of solutes chromatographed under identical conditions, the retention parameters could be approximated by a non-linear combination of logP, logD, pKa, surface tension, parachor, molar volume and to minor extend by polarisability, reetractivity index and density. This study has demonstrated that the use ANNs techniques can result in much more efficient use of experimental information. As HPLC is the most popular analytical technique, improvements in HPLC methods development can yield significant gains in the overall analytical effort. The ANNs extension presented could be the method of choice in some advanced research settings and serves as an indication of the broad potential of neural networks in chromatography analysis.

  14. Evaluation of Haemagglutinin Content by RP-HPLC to Generate Pandemic Influenza Vaccine

    PubMed Central

    Kang, Hyunkyung; Roh, Hang Sik; Song, Hyemin; Lee, Kwangmoon; Chung, Seung-Tae; Ban, Sang-ja; Mo, In Pil; An, Beum-Soo; Ahn, Chi-Young

    2016-01-01

    The potency of influenza vaccine is determined based on its hemagglutinin (HA) content. In general, single radial immunodiffusion (SRID) assay has been utilized as the standard method to measure HA content. However, preparation of reagents for SRID such as antigen and antibody takes approximately 2~3 months, which causes delays in the development of influenza vaccine. Therefore, quantification of HA content by other alternative methods is required. In this study, we measured HA contents of H1N1 antigen and H1N1 influenza vaccine by reverse phase-high performance liquid chromatography (RP-HPLC) methods. The presence of HA1 and HA2 was investigated by silver staining and Western blot assay. In addition, accuracy and repeatability of HA measurement by RP-HPLC were evaluated. Comparison of HA concentration by SRID and RP-HPLC revealed a precise correlation between the two methods. Our results suggest that RP-HPLC assay can replace SRID in the event of a pandemic flu outbreak for rapid vaccine development. PMID:27818728

  15. FTIR assay method for UV inactive drug carisoprodol and identification of degradants by RP-HPLC and ESI-MS.

    PubMed

    Acharya, Pratap Chandra; Vasi, Ruqaiya; Suares, Divya

    2016-09-01

    A new method of analysis has been developed for UV inactive drug carisoprodol using FTIR spectroscopy. These methods were validated for various parameters according to ICH guidelines. The proposed method has also been successfully applied for the determination of the drug concentration in a tablet formulation. The method proved to be accurate (mean percentage recovery between 95 and 105%), precise and reproducible (relative standard deviation<2%), while being simple, economical and less time consuming than other methods and can be used for routine estimation of carisoprodol in the pharmaceutical industry. The developed method also implicates its utility for other UV inactive substances. The stability of the drug under various stress conditions was studied and the drug was found to be particularly susceptible to alkaline hydrolysis. Degradation products of the alkaline hydrolysis were detected by RP-HPLC and tentatively identified by ESI-MS.

  16. Quantification of an intact monoclonal antibody, rituximab, by (RP)HPLC/DAD in compliance with ICH guidelines.

    PubMed

    Navas, Natalia; Herrera, Agustín; Martínez-Ortega, Antonio; Salmerón-García, Antonio; Cabeza, José; Cuadros-Rodríguez, Luis

    2013-11-01

    We studied the quantification of an intact therapeutic monoclonal antibody (mAb), rituximab (RTX), using (reversephase) high-performance liquid chromatography with diode array detection ((RP)HPLC/DAD). To this end, we developed a chromatographic method and validated it as stabilityindicating in accordance with the International Conference on Harmonization guidelines (ICH). A 300-Å C8 column (250 mm×4.6 mm, 5 μm) was used to perform the analysis, and the temperature was maintained at 70 °C. Although only one mAb was analyzed, it was necessary to apply a gradient to elute it with a complex organic mixture. Chromatograms were registered at several wavelengths, with λ =214 nm employed for quantification purposes. The method was developed to quantify marketed RTX under typical hospital administration conditions. Further dilution was avoided in order to prevent additional mAb modification, and in this way the method was shown to be linear from 60 to 5000 mg/L. The precision of the method (repeatability and intermediate precision, estimated as the relative standard deviation, RSD %), was less than 1.0 %. Accuracy, specificity, robustness, and system suitability were also evaluated as specified in the ICH guidelines.We conducted a comprehensive chromatographic analysis by submitting RTX to several informative stress conditions. These forced degradation studies were conducted for two reasons: to estimate the specificity of the method, and to evaluate the robustness of the mAb formulation against external stress factors when handling it in preparation for administration. Thus, we investigated the effects of acid, base, oxidation, ionic strength, temperature, and UV light. Although a slight modification to the intact mAb could not be distinguished chromatographically in the stress studies we conducted, the procedure proposed here to evaluate peak purity enabled us to detect it with a satisfactory level of confidence. The proposed method could therefore be considered

  17. Development and validation of a RP-HPLC method for the determination of zidovudine and its related substances in sustained-release tablets.

    PubMed

    dos Santos, Jucimary V; de Carvalho, Luís A E Batista; Pina, M Eugénia

    2011-01-01

    A reversed-phase high-performance liquid chromatography (RP-HPLC) method for the rapid and accurate quantification of zidovudine (AZT) in sustained release tablets during stability testing was developed. A Waters RP-18 XTerra™(®) column, using a water:methanol (80:20, v/v%) mobile phase at a flow rate of 1.0 ml min(-1), and UV detection at 266 nm, was employed. The method of validation parameters indicate a linear range of between 40.0 to 220.0 µg ml(-1) with an LOQ of 1.985 µg ml(-1) and an LOD of 0.655 µg ml(-1) for the analyte. The degradation products of AZT were isolated and characterized for the first time. There was a very little decline of antiviral by heat, and AZT did not completely degrade either by acid or alkaline hydrolysis. On the other hand, oxidation caused a higher degradation stress in the drug. Finally, the degradation products resulting from stress studies were not found to interfere with the detection of antiviral, which is an advantage of the presently proposed method.

  18. HPTLC and RP-HPLC methods for simultaneous determination of Paracetamol and Pamabrom in presence of their potential impurities.

    PubMed

    Abdelaleem, Eglal A; Naguib, Ibrahim A; Hassan, Eman S; Ali, Nouruddin W

    2015-10-10

    Two chromatgraphic methods were developed for determination of Paracetamol (PCM) and Pamabrom (PAM) in presence of P-aminophenol (PAP) and Theophylline (THEO) as potential impurities of both drugs respectively. First method is HPTLC which depends on separation and quantitation of the studied drugs on aluminum plates pre-coated with silica gel 60 F₂₅₄ as a stationary phase using chloroform:methanol:ethyl acetate:glacial acetic acid (8:0.8:0.6:0.2, v/v/v/v) as mobile phase followed by densitometric measurement of the bands at 254 nm. Second method is RP-HPLC which comprises separation of the studied drugs on a Phenomenex C8 column by gradient elution using mobile phase consisting of sodium dihydrogen phosphate buffer (0.05 M): methanol:acetonitrile (85:10:5, v/v/v) at a flow rate of 1 mL/min for first 7.5 min and (70:20:10, v/v/v) at a flow rate of 1.5 mL/min for the next 5 min. The proposed methods were successfully applied for determination of the potential impurities of PCM and PAM after resolving them from the pure drugs. The developed methods have been validated and proved to meet the requirements delineated by ICH guidelines with respect to linearity, accuracy, precision, specificity and robustness. The validated methods were successfully applied for determination of the studied drugs in their pharmaceutical formulation. The results were statistically compared to those obtained by the reported RP-HPLC method where no significant difference was found; indicating the ability of proposed methods to be used for routine quality control analysis of these drugs.

  19. [Determination of arbutin in the herbs of Vaccinium vitis-idaea L. by RP-HPLC].

    PubMed

    Sun, H; Wang, X; Huang, R; Yuan, C

    1997-09-01

    Determination of arbutin in the herbs of Vaccinium vitis-idaea has been carried out by RP-HPLC, using Inertsil-ODS column (4.6 mm x 250 mm) and mobile phase of methanol and water (15:85), and detecting at 280 nm wavelength. The average content of arbutin is 4.44%, RSD = 2.93%; the recovery rate is 100.7%, RSD = 2.85%.

  20. A Study of Method Development, Validation, and Forced Degradation for Simultaneous Quantification of Paracetamol and Ibuprofen in Pharmaceutical Dosage Form by RP-HPLC Method

    PubMed Central

    Jahan, Md. Sarowar; Islam, Md. Jahirul; Begum, Rehana; Kayesh, Ruhul; Rahman, Asma

    2014-01-01

    A rapid and stability-indicating reversed phase high-performance liquid chromatography (RP-HPLC) method was developed for simultaneous quantification of paracetamol and ibuprofen in their combined dosage form especially to get some more advantages over other methods already developed for this combination. The method was validated according to United States Pharmacopeia (USP) guideline with respect to accuracy, precision, specificity, linearity, solution stability, robustness, sensitivity, and system suitability. Forced degradation study was validated according to International Conference on Harmonisation (ICH). For this, an isocratic condition of mobile phase comprising phosphate buffer (pH 6.8) and acetonitrile in a ratio of 65:35, v/v at a flow rate of 0.7 mL/minute over RP C18 (octadecylsilane (ODS), 150 × 4.6 mm, 5 μm, Phenomenex Inc.) column at ambient temperature was maintained. The method showed excellent linear response with correlation coefficient (R2) values of 0.999 and 1.0 for paracetamol and ibuprofen respectively, which were within the limit of correlation coefficient (R2 > 0.995). The percent recoveries for two drugs were found within the acceptance limit of (97.0–103.0%). Intra-and inter-day precision studies of the new method were less than the maximum allowable limit percentage of relative standard deviation (%RSD) ≤ 2.0. Forced degradation of the drug product was carried out as per the ICH guidelines with a view to establishing the stability-indicating property of this method and providing useful information about the degradation pathways, degradation products, and how the quality of a drug substance and drug product changes with time under the influence of various stressing conditions. The degradation of ibuprofen was within the limit (5–20%, according to the guideline of ICH), while paracetamol showed <20% degradation in oxidation and basic condition. PMID:25452691

  1. A Study of Method Development, Validation, and Forced Degradation for Simultaneous Quantification of Paracetamol and Ibuprofen in Pharmaceutical Dosage Form by RP-HPLC Method.

    PubMed

    Jahan, Md Sarowar; Islam, Md Jahirul; Begum, Rehana; Kayesh, Ruhul; Rahman, Asma

    2014-01-01

    A rapid and stability-indicating reversed phase high-performance liquid chromatography (RP-HPLC) method was developed for simultaneous quantification of paracetamol and ibuprofen in their combined dosage form especially to get some more advantages over other methods already developed for this combination. The method was validated according to United States Pharmacopeia (USP) guideline with respect to accuracy, precision, specificity, linearity, solution stability, robustness, sensitivity, and system suitability. Forced degradation study was validated according to International Conference on Harmonisation (ICH). For this, an isocratic condition of mobile phase comprising phosphate buffer (pH 6.8) and acetonitrile in a ratio of 65:35, v/v at a flow rate of 0.7 mL/minute over RP C18 (octadecylsilane (ODS), 150 × 4.6 mm, 5 μm, Phenomenex Inc.) column at ambient temperature was maintained. The method showed excellent linear response with correlation coefficient (R (2)) values of 0.999 and 1.0 for paracetamol and ibuprofen respectively, which were within the limit of correlation coefficient (R (2) > 0.995). The percent recoveries for two drugs were found within the acceptance limit of (97.0-103.0%). Intra-and inter-day precision studies of the new method were less than the maximum allowable limit percentage of relative standard deviation (%RSD) ≤ 2.0. Forced degradation of the drug product was carried out as per the ICH guidelines with a view to establishing the stability-indicating property of this method and providing useful information about the degradation pathways, degradation products, and how the quality of a drug substance and drug product changes with time under the influence of various stressing conditions. The degradation of ibuprofen was within the limit (5-20%, according to the guideline of ICH), while paracetamol showed <20% degradation in oxidation and basic condition.

  2. Determination of flavonoids in Semen Cuscutae by RP-HPLC.

    PubMed

    Ye, Min; Li, Yan; Yan, Yuning; Liu, Huwei; Ji, Xiuhong

    2002-05-15

    Flavonoids contents in 40 samples of Semen Cuscutae collected from areas all around China were investigated. Five principal flavonoids, quercetin 3-O-beta-D-galactoside-7-O-beta-D-glucoside, quercetin 3-O-beta-D-apiofuranosyl-(1-->2)-beta-D-galactoside, hyperoside, quercetin and kaempferol were analyzed simultaneously by using a reversed phase liquid chromatograph system with 0.025 M phosphoric acid-methanol as mobile phase. The recovery of the method was 97.0-102.9%, and all the flavonoids showed good linearity (r > or = 0.9990) in a relatively wide concentration range. The results indicated that contents of flavonoids in S. Cuscutae varied significantly from species to species, locality to locality, and parasiting host to host. Cuscuta australis contained a much higher content of kaempferol than C. chinensis, and few flavonoids were detected in C. japonica. The quality of S. Cuscutae can be evaluated according to the contents of flavonoids.

  3. Determination of log P values of new cyclen based antimalarial drug leads using RP-HPLC.

    PubMed

    Rudraraju, A V; Amoyaw, P N A; Hubin, T J; Khan, M O F

    2014-09-01

    Lipophilicity, expressed by log P, is an important physicochemical property of drugs that affects many biological processes, including drug absorption and distribution. The main purpose of this study to determine the log P values of newly discovered drug leads using reversed-phase high-performance liquid chromatography (RP-HPLC). The reference standards, with varying polarity ranges, were dissolved in methanol and analyzed by RP-HPLC using a C18 column. The mobile phase consisted of a mixture of acetonitrile, methanol and water in a gradient elution mode. A calibration curve was plotted between the experimental log P values and obtained log k values of the reference standard compounds and a best fit line was obtained. The log k values of the new drug leads were determined in the same solvent system and were used to calculate the respective log P values by using the best fit equation. The log P vs. log k data gave a best fit linear curve that had an R2 of 0.9786 with Pvalues of the intercept and slope of 1.19 x 10(-6) and 1.56 x 10(-10), respectively, at 0.05 level of significance. Log P values of 15 new drug leads and related compounds, all of which are derivatives of macrocyclic polyamines and their metal complexes, were determined. The values obtained are closely related to the calculated log P (Clog P) values using ChemDraw Ultra 12.0. This experiment provided efficient, fast and reasonable estimates of log P values of the new drug leads by using RP-HPLC.

  4. Analytics of the therapeutic peptide aviptadil by sheathless CE-MS and comparison with nanoRP-HPLC-MS.

    PubMed

    Gross, Peter C; Burkart, Sonja C; Müller, Rolf

    2014-01-01

    Purification and quality control of therapeutic peptides is often performed by one single method, RP-HPLC. As usage of an orthogonal technique is highly advisable for quality assurance, capillary electrophoresis (CE) employing a coated capillary coupled via a sheathless interface to a mass spectrometer was applied in parallel. The basic therapeutic peptide aviptadil served as a model substance to study the impurity profiles revealing 15 detectable impurities using CE-MS, two were detected by an appropriate nanoRP-HPLC-MS method. None of the impurities detected by CE were observed in LC and vice versa. The LOD in CE-MS was determined in the base peak electropherogram at ∼1fmol, a value 2500 times smaller than the LOD found in nanoRP-HPLC-MS (3pmol). In nanoRP-HPLC-MS only 0.2% of the extrapolated CE-MS signal for a 25ng aviptadil load was observed. We conclude that both, the LOD as well as the impurity profile of aviptadil, as analyzed by nanoRP-HPLC are influenced by both, the ligand-derivatized silica matrix and the flow-rate. Peptides may disappear completely and their variable emergence may lead to the determination of incorrect ratios as present in the sample.

  5. Simultaneous determination of nine model compounds in permeability samples using RP-HPLC: application to prove the cassette administration principle in single pass intestinal perfusion study in rats.

    PubMed

    Wahajuddin; Singh, Sheelendra Pratap; Raju, K S R; Nafis, Asad; Jain, Girish Kumar

    2012-01-01

    A simple, sensitive and specific reversed phase high performance liquid chromatographic (RP-HPLC) method for simultaneous determination of atenolol, paracetamol, hydrochlorothiazide, caffeine, cephalexin, metoprolol, propranolol, ketoprofen along with phenol red (a non-absorbable compound) in samples obtained from intestinal in situ single-pass perfusion studies, was developed and validated. Chromatography was carried out on RP18 column with mobile phase comprising of 10 mM phosphate buffer (pH 2.5) and methanol in gradient mode. The calibration curves were linear for all nine permeability model compounds (r² > 0.999) across the concentration range of 1.25-40 μg/ml. The coefficient of variation for intra and inter-day assay precision was between 0.04 and 3.08% and the accuracy was between 98.39 and 109.45%. Stability studies were carried out at different storage conditions and all the analytes were found to be stable. The method was successfully applied for analysing the permeability samples obtained from in situ single pass perfusion studies. The effective permeability (P(eff)) values obtained upon cassette administration were in close proximity to the permeability values obtained upon single administration of model compounds. In conclusion, the developed RP-HPLC method can be used for high throughput cassette validation of rat in situ perfusion model for intestinal permeability assessment.

  6. Development, Validation and Application of RP-HPLC Method: Simultaneous Determination of Antihistamine and Preservatives with Paracetamol in Liquid Formulations and Human Serum

    PubMed Central

    Hasan, Najmul; Chaiharn, Mathurot; Toor, Umair Ali; Mirani, Zulfiqar Ali; Sajjad, Ghulam; Sher, Nawab; Aziz, Mubashir; Siddiqui, Farhan Ahmed

    2016-01-01

    In this article we describe development and validation of stability indicating, accurate, specific, precise and simple Ion-pairing RP-HPLC method for simultaneous determination of paracetamol and cetirizine HCl along with preservatives i.e. propylparaben, and methylparaben in pharmaceutical dosage forms of oral solution and in serum. Acetonitrile: Buffer: Sulfuric Acid (45:55:0.3 v/v/v) was the mobile phase at flow rate 1.0 mL min-1 using a Hibar® Lichrosorb® C18 column and monitored at wavelength of 230nm. The averages of absolute and relative recoveries were found to be 99.3%, 99.5%, 99.8% and 98.7% with correlation coefficient of 0.9977, 0.9998, 0.9984, and 0.9997 for cetirizine HCl, paracetamol, methylparaben and Propylparaben respectively. The limit of quantification and limit of detection were in range of 0.3 to 2.7 ng mL-1 and 0.1 to 0.8 ng mL-1 respectively. Under stress conditions of acidic, basic, oxidative, and thermal degradation, maximum degradation was observed in basic and oxidative stress where a significant impact was observed while all drugs were found almost stable in the other conditions. The developed method was validated in accordance with ICH and AOAC guidelines. The proposed method was successfully applied to quantify amount of paracetamol, cetirizine HCl and two most common microbial preservatives in bulk, dosage form and physiological fluid. PMID:27651840

  7. RP-HPLC method development and validation for simultaneous estimation of atorvastatin calcium and pioglitazone hydrochloride in pharmaceutical dosage form.

    PubMed

    Peraman, Ramalingam; Mallikarjuna, Sasikala; Ammineni, Pravalika; Kondreddy, Vinod kumar

    2014-10-01

    A simple, selective, rapid, precise and economical reversed-phase high-performance liquid chromatographic (RP-HPLC) method has been developed for simultaneous estimation of atorvastatin calcium (ATV) and pioglitazone hydrochloride (PIO) from pharmaceutical formulation. The method is carried out on a C8 (25 cm × 4.6 mm i.d., 5 μm) column with a mobile phase consisting of acetonitrile (ACN):water (pH adjusted to 6.2 using o-phosphoric acid) in the ratio of 45:55 (v/v). The retention time of ATV and PIO is 4.1 and 8.1 min, respectively, with the flow rate of 1 mL/min with diode array detector detection at 232 nm. The linear regression analysis data from the linearity plot showed good linear relationship with a correlation coefficient (R(2)) value for ATV and PIO of 0.9998 and 0.9997 in the concentration range of 10-80 µg mL(-1), respectively. The relative standard deviation for intraday precision has been found to be <2.0%. The method is validated according to the ICH guidelines. The developed method is validated in terms of specificity, selectivity, accuracy, precision, linearity, limit of detection, limit of quantitation and solution stability. The proposed method can be used for simultaneous estimation of these drugs in marketed dosage forms.

  8. Validated RP-HPLC and TLC-Densitometric Methods for Analysis of Ternary Mixture of Cetylpyridinium Chloride, Chlorocresol and Lidocaine in Oral Antiseptic Formulation.

    PubMed

    Abdelwahab, Nada S; Ali, Nouruddin W; Abdelkawy, M; Emam, Aml A

    2016-03-01

    This work was concerned with development, optimization, application and validation of reversed phase high performance liquid chromatography (RP-HPLC) and thin layer chromatography (TLC)-densitometric methods for analysis of cetylpyridinium chloride, chlorocresol and lidocaine in Canyon(®) gel. The first developed RP-HPLC method depended on chromatographic separation on a ZORBAX Eclipse Plus C8 column, with elution with a mobile phase consisting of 0.05% phosphoric acid solution : acetonitrile : methanol (15 : 24 : 61, by volume), pumping the mobile phase at a flow rate of 1.00 mL min(-1), with ultraviolet detection at 220 nm. While in the subsequently developed method, the TLC-densitometric method, complete separation of the studied mixture was achieved using methanol : acetone : acetic acid (7 : 3 : 0.2, by volume) as a mobile phase, aluminum plates precoated with silica gel 60 F254 as a stationary phase and 215 nm as the scanning wavelength. Factors affecting the developed methods were studied and optimized; moreover, methods had been validated as per the International Conference of Harmonization guideline and the results indicated that the suggested methods were reproducible, reliable and applicable for rapid routine analysis. Statistical comparison of the two developed methods with the reported HPLC ones using F- and Student's t tests showed no significant difference.

  9. Stability indicating methods for the determination of clozapine.

    PubMed

    Hasan, Nagiba Y; Elkawy, Mohamed A; Elzeany, Badr E; Wagieh, Nour E

    2002-08-22

    Five new selective, precise and accurate methods are described for the determination of clozapine in the presence of its main degradation product. Method A utilizes the second and third derivative spectrophotometry at 315 and 305 nm, respectively. Method B is RSD(1) spectrophotometric method based on the simultaneous use of the first derivative of ratio spectra and measurement at 295 nm. Method C is a pH-induced difference (delta A) spectrophotometry using UV measurement at 325 nm. Method D is a densitometric one, after separation on silica gel plate using methanol: water as mobile phase, and the spot was scanned at 295 nm. Method E is RP-HPLC using acetonitrile: water (40:60 v/v) as mobile phase at a flow rate of 1 ml/min and UV detection was at 295 nm. Regression analysis showed good correlation in the concentration ranges 3-10, 4-10, 10-25 micro g/ml, 200-1000 ng/spot, 5-100 micro g/ml with percentage recoveries of 99.4+/-0.28, 99.8+/-0.20, 100.05+/-0.11, 99.41+/-0.34, 100.11+/-0.07 and 100.07+/-0.05% for methods A, B, C, D and E, respectively. These methods are suitable as stability indicating methods for the determination of clozapine in the presence of its main degradation product either in bulk powder or in pharmaceutical formulations.

  10. Development of a novel RP-HPLC method for the efficient separation of aripiprazole and its nine impurities.

    PubMed

    Nikolic, Katarina; Filijović, Nataša Djordjević; Maričić, Borislava; Agbaba, Danica

    2013-10-01

    The development of an RP-HPLC method for the separation of aripiprazole and its nine impurities was performed with the use of partial least squares regression, response surface plot methodology, and chromatographic response function. The HPLC retention times and computed molecular parameters of the aripiprazole and its nine impurities were further used for the quantitative structure-retention relationship (QSRR) study. The QSRR model, R(2):0.899, Q(2):0.832, root mean square error of estimation: 4.761, root mean square error of prediction: 6.614, was developed. Very good agreement between the predicted and observed retention times (t(R)) for three additional aripiprazole impurities (TC1-TC3) indicated the high prediction potential of the QSRR model for tR evaluation of other aripiprazole impurities and metabolites. The developed HPLC method is the first reported method for the efficient separation of aripiprazole and its nine impurities, which could be used for the analysis of an additional three aripiprazole impurities (TC1-TC3).

  11. Use of thiolysis hyphenated to RP-HPLC-ESI(-)-MS/MS for the analysis of flavanoids in fresh lager beers.

    PubMed

    Callemien, Delphine; Guyot, Sylvain; Collin, Sonia

    2008-10-15

    Proanthocyanidins are well known for their involvement in haze and colour development during beer ageing. New methodologies are needed, however, to understand what happens to them in the bottled beer. For the first time in the brewing field, thiolysis was hyphenated to RP-HPLC-ESI(-)-MS/MS to investigate these flavanoids. Thirty minutes at 40°C followed by 10h at room temperature emerged as the best conditions for complete depolymerisation. NP-HPLC-ESI(-)-MS/MS was used to quantify and isolate fractions from monomers to trimers in a Sephadex LH20 acetone/water (70/30, v/v) beer extract. Unsurprisingly, a lower dimer/monomer ratio was evidenced in PVPP-treated beers than in silica gel-filtered beers. Most beer dimers are procyanidins B3 (two catechin units) whilst most trimers are prodelphinidins (catechin in terminal units and gallocatechins or catechins in extension units). Gallocatechin appeared to come mainly from malt. Despite the absence of chromatographic peaks corresponding to oligomers above trimers, an apparent degree of polymerisation close to six was calculated in the total LH20 extract. Still higher mean degrees of polymerisation (mDPs) were calculated for malt and hop, indicating selective extraction or depolymerisation from raw materials to beer. The main part of beer polyphenols is composed of complex undefined structures not degraded by toluene-α-thiol.

  12. Stability indicating studies on NMITLI 118RT+ (standardized extract of withania somnifera dunal)

    PubMed Central

    Ahmad, Hafsa; Khandelwal, Kiran; Pachauri, Shakti Deep; Sanghwan, Rajender Singh; Dwivedi, Anil Kumar

    2014-01-01

    Background: Withania somnifera Dunal (Ashwagandha) is an Indian medicinal plant of great medicinal value; used in many clinically proven conditions. NMITLI-118RT+ is a candidate drug under a Council of Scientific and Industrial Research (CSIR) networking project. It is a chemotype of W. somnifera's root extract, which has been used for the present study. Objectives: The present investigation aims to develop and validate a simple isocratic reverse phase-high performance liquid chromatography (RP-HPLC) system for the detection and estimation of Withanolide A (marker compound) and its analytical application for stability indicating studies on NMITLI-118RT+. Material and Methods: A validated RP-HPLC method for Withanolide A was established on a Waters HPLC system and the same was used on NMITLI-118RT+ for quantification and fingerprinting purposes, and for establishing forced degradation, isothermal stress tests, and drug-excipient testing protocols as per International Conference on Harmonization (ICH) guidelines. Results: A validated method was established, which could detect the marker at a retention time of around 6.3 minutes, with a linearity range of 2-100 μg/mL, by varying the amounts of the said marker, which were estimated in four different batches of NMITLI-118RT+. Photostability as per ICH guidelines suggested a slight loss of the active constituent and maximum degradation was afforded with alkali followed by acid, and then peroxide, in the forced degradation studies. In the drug-excipient studies, the maximum amount of active constituent could be detected in the samples with ethyl cellulose and the least with hydroxy propyl cellulose. Conclusion: The method developed here was simple and rapid. The various stability indicating studies carried out in the present investigation would be useful for formulation development and were suggestive of deciding the recommended storage conditions for NMITLI-118RT+. PMID:25210308

  13. Determination of some phenolic compounds in red wine by RP-HPLC: method development and validation.

    PubMed

    Burin, Vívian Maria; Arcari, Stefany Grützmann; Costa, Léa Luzia Freitas; Bordignon-Luiz, Marilde T

    2011-09-01

    A methodology employing reversed-phase high-performance liquid chromatography (RP-HPLC) was developed and validated for simultaneous determination of five phenolic compounds in red wine. The chromatographic separation was carried out in a C(18) column with water acidify with acetic acid (pH 2.6) (solvent A) and 20% solvent A and 80% acetonitrile (solvent B) as the mobile phase. The validation parameters included: selectivity, linearity, range, limits of detection and quantitation, precision and accuracy, using an internal standard. All calibration curves were linear (R(2) > 0.999) within the range, and good precision (RSD < 2.6%) and recovery (80-120%) was obtained for all compounds. This method was applied to quantify phenolics in red wine samples from Santa Catarina State, Brazil, and good separation peaks for phenolic compounds in these wines were observed.

  14. Development and validation of a novel RP-HPLC method for the analysis of reduced glutathione.

    PubMed

    Sutariya, Vijaykumar; Wehrung, Daniel; Geldenhuys, Werner J

    2012-03-01

    The objective of this study was the development, optimization, and validation of a novel reverse-phase high-pressure liquid chromatography (RP-HPLC) method for the quantification of reduced glutathione in pharmaceutical formulations utilizing simple UV detection. The separation utilized a C18 column at room temperature and UV absorption was measured at 215 nm. The mobile phase was an isocratic flow of a 50/50 (v/v) mixture of water (pH 7.0) and acetonitrile flowing at 1.0 mL/min. Validation of the method assessed the methods ability in seven categories: linearity, range, limit of detection, limit of quantification, accuracy, precision, and selectivity. Analysis of the system suitability showed acceptable levels of suitability in all categories. Likewise, the method displayed an acceptable degree of linearity (r(2) = 0.9994) over a concentration range of 2.5-60 µg/mL. The detection limit and quantification limit were 0.6 and 1.8 µg/mL respectively. The percent recovery of the method was 98.80-100.79%. Following validation the method was employed in the determination of glutathione in pharmaceutical formulations in the form of a conjugate and a nanoparticle. The proposed method offers a simple, accurate, and inexpensive way to quantify reduced glutathione.

  15. Determination of phenolic compounds derived from hydrolysable tannins in biological matrices by RP-HPLC.

    PubMed

    Díez, María Teresa; García del Moral, Pilar; Resines, José Antonio; Arín, María Jesús

    2008-08-01

    An RP-HPLC method for the determination of four phenolic compounds: gallic acid (GA), pyrogallol (PY), resorcinol (RE) and ellagic acid (EA), derived from hydrolysable tannins is reported. Separation was achieved on a SunFire C18 (250 x 4.6 mm id, 5 microm) column at 40 degrees C with gradient elution. UV detection at 280 nm was applied. The developed method was validated in terms of linearity, accuracy and precision. Satisfactory repeatability and between day precision were noticed with RSD values lower than 3%. Recoveries from different biological samples ranged from 91.50 to 105.25%. The LODs were estimated as 1.70 mg/L for PY, 1.68 mg/L for GA, 1.52 mg/L for RE and 0.98 mg/L for EA with a 20 microL injection volume. The method was applied for the determination of these compounds in oak leaves and in ruminal fluid and urine samples taken from beef cattle fed with oak leaves. The proposed method could be used in ruminant nutrition studies to verify the effect that a diet rich in tannins have on ruminal fermentation and to determine the toxicity of these compounds.

  16. The Determination of Food Dyes in Vitamins by RP-HPLC.

    PubMed

    Šuleková, Monika; Hudák, Alexander; Smrčová, Miroslava

    2016-10-17

    Reversed-phase high performance liquid chromatography (RP-HPLC) for the determination of five synthetic food dyes (Quinoline Yellow E104, Sunset Yellow E110, Ponceau 4R E124, Tartrazine E102 and Carmine E120) in vitamins was used. The dyes were analyzed within 10 min using a column with stationary phase C 18 (250 mm × 4.6 mm, 5 μm) at 40 °C with isocratic elution, and the mobile phase contained acetonitrile and a mixture of CH₃COONa:CH₃OH (85:15, v/v) in a ratio of 10:90 (v/v) for yellow-colored capsules and 20:80 (v/v) for red-colored capsules, respectively. A diode-array detector was used to monitor the dyes between 190 and 800 nm. It was established that the analyzed samples contained synthetic dyes in a concentration range from 79.5 ± 0.01 μg/capsule of Ponceau 4R, E124 to 524 ± 0.01 μg/capsule of Tartrazine, E102. The obtained results were compared with existing acceptable daily intakes (ADIs) for individual dyes. This paper provides information about the content of dyes in samples of vitamins. This information is not generally available to consumers.

  17. Investigation on the origin of 5-HMF in Shengmaiyin decoction by RP-HPLC method*

    PubMed Central

    Li, Ying-hua; Lu, Xiu-yang

    2005-01-01

    The origin of 5-HMF (5-hydroxymethyl-2-furaldehyde) in a Shengmaiyin decoction was investigated by the RP-HPLC method below. A C18 column (250 mm×4.6 mm, i.d. 5 μm) with a column temperature of 25 °C was used. The mobile phase was a mixture of ultra-pure water-acetonitrile (95:5, V/V) and the flow rate was 1.0 ml/min. The detection wavelength was 280 nm. The injection volume was 1 μl and the running time was about 20 min. The addition of Schisandra was regulated to assess the contribution of an acid environment to the production of 5-HMF. In order to confirm the role of saccharides in the production of 5-HMF, different amount of fructose was used. The 5-HMF level in decoctions of processed and unprocessed Schisandra was investigated in order to determine the origin of 5-HMF. The results showed that 5-HMF was derived mainly from the decoction of Schisandra only and not the mixed decoction of Ophionpogon and Schisandra. The appearance of 5-HMF is not simply the result of the decomposition of saccharides under the acid environment created by Schisandra, but the processing procedure plays an important role in the production of 5-HMF. PMID:16187416

  18. Determination of azelaic acid in pharmaceuticals and cosmetics by RP-HPLC after pre-column derivatization.

    PubMed

    Ferioli, V; Rustichelli, C; Vezzalini, F; Gamberini, G

    1994-06-01

    This paper reports a RP-HPLC method for the determination in topics of azelaic acid, a keratolytic and anti-comedogenic agent widely used in the treatment of all types of acne. A derivatization step was needed prior to chromatographic analysis because the analyte is lacking in chromophore. A sample clean-up procedure by solid-phase extraction was also developed to analyse azelaic acid in complex matrices, such as pharmaceutical and cosmetic formulations.

  19. DEVELOPMENT AND VALIDATION OF THE STABILITY-INDICATING LC-UV METHOD FOR DETERMINATION OF CEFOZOPRAN HYDROCHLORIDE.

    PubMed

    Zalewski, Przemysław; Garbacki, Piotr; Cielecka-Piontek, Judyta; Bednarek-Rajewska, Katarzyna; Krause, Anna

    2015-01-01

    The stability-indicating LC assay method was developed and validated for quantitative determination of cefozopran hydrochloride (CZH) in the presence of degradation products formed during the forced degradation studies. An isocratic, RP-HPLC method was developed with C-18 (250 mm x 4.6 mm, 5 µm) column and 12 mM ammonium acetate-acetonitrile (92:8, v/v) as a mobile phase. The flow rate of the mobile phase was 1.0 mL/min. Detection wavelength was 260 not and temperature was 30°C. Cefozopran hydrochloride as other cephalosporins was subjected to stress conditions of degradation in aqueous solutions including hydrolysis, oxidation, photolysis and thermal degradation. The developed method was validated with regard to linearity, accuracy, precision, selectivity and robustness. The method was applied successfully for identification and determination of cefozopran hydrochloride in pharmaceuticals and during kinetic studies.

  20. Development and validation of stability-indicating HPLC method for simultaneous determination of meropenem and potassium clavulanate.

    PubMed

    Zalewski, Przemysław; Cielecka-Piontek, Judyta; Paczkowska, Magdalena

    2014-01-01

    A stability-indicating LC assay method was developed and validated for a simultaneous determination of meropenem and potassium clavulanate in the presence of degradation products formed during acid-base hydrolysis, oxidation and thermolysis. The isocratic RP-HPLC method was developed with a LiChrospher RP-18 (250 mm x 4.6 mm, 5 microm) column and gradient elution of 12 mmol/L ammonium acetate and acetonitrile. The flow rate of the mobile phase was 1.0 mL/min, the detection wavelength 220 nm and the temperature 303 K. The method was validated with regard to linearity, accuracy, precision, selectivity and robustness, and was applied successfully for the determination of meropenem and potassium clavulanate separately as well as jointly in pharmaceutical formulations.

  1. Predicting retention time shifts associated with variation of the gradient slope in peptide RP-HPLC.

    PubMed

    Spicer, Vic; Grigoryan, Marine; Gotfrid, Alexander; Standing, Kenneth G; Krokhin, Oleg V

    2010-12-01

    We have developed a sequence-specific model for predicting slopes (S) in the fundamental equation of linear solvent strength theory for the reversed-phase HPLC separation of tryptic peptides detected in a typical bottom-up-proteomics experiment. These slopes control the variation in the separation selectivity observed when the physical parameters of chromatographic separation, such as gradient slope, flow rate, and column size are altered. For example, with the use of an arbitrarily chosen set of tryptic peptides with a 4-times difference in the gradient slope between two experiments, the R(2)-value of correlation between the observed retention times of identical species decreases to ~0.993-0.996 (compared to a theoretical value of ~1.00). The observed retention time shifts associated with variations of the gradient slope can be predicted a priori using the approach described here. The proposed model is based on our findings for a set of synthetic species (Vu, H.; Spicer, V.; Gotfrid, A.; Krokhin, O. V. J. Chromatogr., A, 2010, 1217, 489-497), which postulate that slopes S can be predicted taking into account simultaneously peptide length, charge, and hydrophobicity. Here we extend this approach using an extensive set of real tryptic peptides. We developed the procedure to accurately measure S-values in nano-RP HPLC MS experiments and introduced sequence-specific corrections for a more accurate prediction of the slopes S. A correlation of ~0.95 R(2)-value between the predicted and experimental S-values was demonstrated. Predicting S-values and calculating the expected retention time shifts when the physical parameters of separation like gradient slope are altered will facilitate a more accurate application of peptide retention prediction protocols, aid in the transfer of scheduled MRM (SRM) procedures between LC systems, and increase the efficiency of interlaboratory data collection and comparison.

  2. An Experimental Design Approach for Impurity Profiling of Valacyclovir-Related Products by RP-HPLC

    PubMed Central

    Katakam, Prakash; Dey, Baishakhi; Hwisa, Nagiat T; Assaleh, Fathi H; Chandu, Babu R; Singla, Rajeev K; Mitra, Analava

    2014-01-01

    Abstract Impurity profiling has become an important phase of pharmaceutical research where both spectroscopic and chromatographic methods find applications. The analytical methodology needs to be very sensitive, specific, and precise which will separate and determine the impurity of interest at the 0.1% level. Current research reports a validated RP-HPLC method to detect and separate valacyclovir-related impurities (Imp-E and Imp-G) using the Box-Behnken design approach of response surface methodology. A gradient mobile phase (buffer: acetonitrile as mobile phase A and acetonitrile: methanol as mobile phase B) was used. Linearity was found in the concentration range of 50–150 μg/mL. The mean recovery of impurities was 99.9% and 103.2%, respectively. The %RSD for the peak areas of Imp-E and Imp-G were 0.9 and 0.1, respectively. No blank interferences at the retention times of the impurities suggest the specificity of the method. The LOD values were 0.0024 μg/mL for Imp-E and 0.04 μg/mL for Imp-G and the LOQ values were obtained as 0.0082 μg/mL and 0.136 μg/mL, respectively, for the impurities. The S/N ratios in both cases were within the specification limits. Proper peak shapes and satisfactory resolution with good retention times suggested the suitability of the method for impurity profiling of valacyclovir-related drug substances. PMID:25853072

  3. Simultaneous determination of paracetamol and lornoxicam by RP-HPLC in bulk and tablet formulation

    PubMed Central

    Attimarad, Mahesh

    2011-01-01

    Aim: The objective of the study was to develop simple RP-HPLC method for the simultaneous determination of paracetamol and lornoxicam without prior separation. Materials and Methods: In this method, Kromasil C8 (250 mm, 4.6 mm, 5 μm) column was used. The mobile phase used was methanol:phosphate buffer (60:40, v/v, pH 6.4), at flow rate of 1 ml min-1. UV detection was monitored at 302 nm. Results: Calibration graphs were established in the range of 1-150 μg ml-1 and 0.5-100 μg ml-1 for paracetamol and lornoxicam, respectively. The average retention time for paracetamol and lornoxicam was found to be 3.15 ± 0.03 min and 5.25 ± 0.06 min, respectively. The detection limit and quantitation limit for paracetamol are 0.19 μg ml-1 and 0.59 μg ml-1 and for lornoxicam 0.10 μg ml-1 and 0.31 μg mL-1, respectively. The intraday and interday precision expressed as percent relative standard deviation were below 2%. The mean recovery of paracetamol and lornoxicam was found to be in the range of 99.03-101.2%. Conclusion: The validated HPLC method was found to be rapid, precise and accurate and can be readily utilized for analysis of paracetamol and lornoxicam in bulk and in pharmaceutical formulations. PMID:23781432

  4. Development and validation of a new stability indicating reversed phase liquid chromatographic method for the determination of prednisolone acetate and impurities in an ophthalmic suspension.

    PubMed

    Marley, Adrian; Stalcup, Apryll M; Connolly, Damian

    2015-01-01

    A new stability indicating reversed phase high performance liquid chromatography (RP-HPLC) method was developed and validated under current International Conference of Harmonisation (ICH) guidance for the determination of prednisolone acetate (PAC) and impurities in an ophthalmic suspension. The developed method is presented as an alternative to a modified version of the current RP-HPLC method described in the USP monograph for the assay of PAC in an ophthalmic suspension. Along with the assay of PAC, the new method is also capable of identifying and quantifying eight selected PAC impurities and degradation products in an ophthalmic suspension. Using an Agilent Poroshell 120 EC-C18 100 mm × 4.6mm (dp: 2.7 μm) column set to 60°C with step gradient elution generated using mobile phase A: acetonitrile/water (10:90) (v/v) and mobile phase B: acetonitrile delivered at 1.2 mL min(-1), all peaks of interest are eluted in 33 min with resolution of 1.5 between the critical pairs. The developed method was validated for PAC and impurities to ICH recommendations for accuracy, linearity, precision (repeatability), limit of detection, limit of quantitation, robustness and specificity.

  5. Development and validation of a stability-indicating HPLC method for simultaneous determination of salicylic acid, betamethasone dipropionate and their related compounds in Diprosalic Lotion.

    PubMed

    Shou, Minshan; Galinada, Wilmer A; Wei, Yu-Chien; Tang, Qinglin; Markovich, Robert J; Rustum, Abu M

    2009-10-15

    Diprosalic Lotion is an anti-inflammatory drug product that contains salicylic acid and betamethasone dipropionate as active pharmaceutical ingredients (APIs). A reversed-phase high performance liquid chromatography (RP-HPLC) method was developed for simultaneous determination of salicylic acid, betamethasone dipropionate, and their related compounds in Diprosalic Lotion. A 150 mm x 4.6 mm I.D. YMC J'sphere ODS-H80 column at 35 degrees C and UV detection at 240 nm was used. A gradient elution was employed using 0.05% (v/v) methanesulfonic acid solution and acetonitrile as mobile phases. A total of thirty three compounds from Diprosalic Lotion samples were separated in 38 min. The stability-indicating capability of this method has been demonstrated by the adequate separation of all the impurities and degradation products in expired stability samples of Diprosalic Lotion. The method was validated as per the current ICH guidelines.

  6. Development and Validation of an RP-HPLC Method for Quantitative Estimation of Eslicarbazepine Acetate in Bulk Drug and Tablets.

    PubMed

    Singh, M; Kumar, L; Arora, P; Mathur, S C; Saini, P K; Singh, R M; Singh, G N

    2013-11-01

    A convenient, simple, accurate, precise and reproducible RP-HPLC method was developed and validated for the estimation of eslicarbazepine acetate in bulk drug and tablet dosage form. Objective was achieved under optimised chromatographic conditions on Dionex RP-HPLC system with Dionex C18 column (250×4.6 mm, 5 μm particle size) using mobile phase composed of methanol and ammonium acetate (0.005 M) in the ratio of 70:30 v/v. The separation was achieved using an isocratic elution method with a flow rate of 1.0 ml/ min at room temperature. The effluent was monitored at 230 nm using diode array detector. The retention time of eslicarbazepine acetate is found to be 4.9 min and the standard calibration plot was linear over a concentration range of 10-90 μg/ml with r(2)=0.9995. The limit of detection and quantification were found to be 3.144 and 9.52 μg/ml, respectively. The amount of eslicarbazepine acetate in bulk and tablet dosage form was found to be 99.19 and 97.88%, respectively. The method was validated statistically using the percent relative standard deviation and the values are found to be within the limits. The recovery studies were performed and the percentage recoveries were found to be 98.33± 0.5%.

  7. Stability-Indicating HPLC Method for the Determination of Cefcapene Pivoxil.

    PubMed

    Zalewski, Przemysław; Cielecka-Piontek, Judyta; Garbacki, Piotr; Jelińska, Anna; Karaźniewicz-Łada, Marta

    2013-04-01

    The stability-indicating LC assay method was developed and validated for quantitative determination of cefcapene pivoxil in the presence of degradation products formed during forced degradation studies. An isocratic RP-HPLC method was developed with a Lichrospher RP-18 (250 mm × 4.6 mm, 5 μm) column and the mobile phase composed of 45 volumes of acetonitrile and 55 volumes of mixture composed of citric acid 10 mmol L(-1) and potassium chloride 18 mmol L(-1). The flow rate of the mobile phase was 1 mL min(-1). Detection wavelength was 270 nm and temperature was 30 °C. Cefcapene pivoxil, similar to other cephalosporins, was subjected to stress conditions of degradation in aqueous solutions including hydrolysis, oxidation, and thermal degradation. The method was validated with regard to linearity, accuracy, precision, selectivity, and robustness. The method was applied successfully for the determination of cefcapene pivoxil during kinetic studies in aqueous solutions (pH and thermal degradation) and in solid state (oxidative, thermal, and radiolytic degradation).

  8. Development and Validation of Stability-indicating HPLC Method for Simultaneous Estimation of Cefixime and Linezolid

    PubMed Central

    Patel, Nidhi S.; Tandel, Falguni B.; Patel, Yogita D.; Thakkar, Kartavya B.

    2014-01-01

    A stability-indicating reverse phase high performance liquid chromatography method was developed and validated for cefixime and linezolid. The wavelength selected for quantitation was 276 nm. The method has been validated for linearity, accuracy, precision, robustness, limit of detection and limit of quantitation. Linearity was observed in the concentration range of 2-12 μg/ml for cefixime and 6-36 μg/ml for linezolid. For RP-HPLC, the separation was achieved by Phenomenex Luna C18 (250×4.6 mm) 5 μm column using phosphate buffer (pH 7):methanol (60:40 v/v) as mobile phase with flow rate 1 ml/min. The retention time of cefixime and linezolid were found to be 3.127 min and 11.986 min, respectively. During force degradation, drug product was exposed to hydrolysis (acid and base hydrolysis), H2O2, thermal degradation and photo degradation. The % degradation was found to be 10 to 20% for both cefixime and linezolid in the given condition. The method specifically estimates both the drugs in presence of all the degradants generated during forced degradation study. The developed methods were simple, specific and economic, which can be used for simultaneous estimation of cefixime and linezolid in tablet dosage form. PMID:25593387

  9. RP-HPLC and chemometrics for wheat flour protein characterisation in an industrial bread-making process monitoring context.

    PubMed

    Li Vigni, Mario; Baschieri, Carlo; Marchetti, Andrea; Cocchi, Marina

    2013-08-15

    In the baking industry, a difficult task is to keep the quality perceived by the consumer as constant as possible, given the inner variability of flour, e.g. due to different wheat mixtures, harvesting time, etc. Here, we evaluated the influence of flour batches properties on bread quality, considering an industrial bread making process. In particular, flour composition in terms of protein fractions (gliadins, glutenins) has been determined by means of RP-HPLC, to assess the inter- and intra-batch variability of flour mixtures deliveries at a baking plant. Multivariate data analysis allowed evaluation of correlation between flour protein composition and technological properties. A great variability within different deliveries of a same flour batch emerged, as well as a considerable seasonal variability. Correlation models among protein sub-fractions, technological properties and bread quality are difficult to establish; however, the role of the protein profile on flour behaviour in bread making could be highlighted.

  10. Quantification of 4'-geranyloxyferulic acid (GOFA) in honey samples of different origin by validated RP-HPLC-UV method.

    PubMed

    Genovese, Salvatore; Taddeo, Vito Alessandro; Fiorito, Serena; Epifano, Francesco

    2016-01-05

    Natural honey has been employed as a nutraceutical agent with benefits and therapeutic promises for humans for many centuries. It has been largely used as food and medicine by all generations, traditions, and civilizations, both ancient and modern. Several chemicals having beneficial effects for human health have been reported as components of natural honey and these include sugars, organic acids, aminoacids, minerals, and vitamins. Also some important phytochemicals have been described and these comprise tannins, flavonoids, terpenes, saponins, and alkaloids. In this note it is described the successful application of a RP HPLC-UV-vis method for the separation and quantification of 4'-geranyloxyferulic acid (GOFA) in four honey samples of different origin. Concentration values showed a great variation between the four samples tested, being chestnut honey the one richest in GOFA (7.87 mg/g). The findings described herein represent the first example reported in the literature of the characterization of an oxyprenylated phenylpropanoid in honey.

  11. Extraction and RP-HPLC determination of taxol in rat plasma, cell culture and quality control samples

    PubMed Central

    Tekade, Rakesh Kumar; D'Emanuele, Antony; Elhissi, Abdelbary; Agrawal, Ashish; Jain, Anurekha; Arafat, Basel Tawfiq; Jain, Narendra Kumar

    2013-01-01

    A rapid, sensitive, selective and validated reverse phase high-performance liquid chromatography (RP-HPLC) method for the estimation of paclitaxel in micro-sample of rat plasma and in culture of cancer cells was performed in this study. The mobile phase consisted of an optimized mixture of methanol:water: trifluroacetic acid (80: 20: 0.1, v/v/v). Column elution at a flow rate of 1 mL/minute with UV detection at 225 nm at room temperature was used. The RP-HPLC method was successfully applied for the determination of paclitaxel in plasma samples and in culture of cancer cells with nano-quantity of estimation. The validation studies were performed in accordance with the International Conference on Harmonization (ICH) guidelines. The intra- and inter-day precision showed that the coefficients of variation ranged from 1.07% to 4.27% at different levels of concentrations. To the best of our knowledge, this study also reported for the first time the optimization of different solvents for effective extraction of paclitaxel wherein tert.-butyl methyl ether (TBME): diethyl ether (DEE) in 50: 50 v/v composition was found most efficient with extraction efficiency ranging between 77.99% and 91.74% and between 76.14 and 93.66% in the plasma and cell culture, respectively. This proposed method was successfully applied to study the pharmacokinetics of paclitaxel and the influence of verapamil and all-trans retinoic acid (atRA) on paclitaxel pharmacokinetics in rat models. This proposed method might emerge as a valuable aid in the laboratory monitoring of paclitaxel in a variety of in vitro as well as in vivo scenarios. PMID:24086173

  12. Development and validation of stability indicating method for the determination of exemestane by reverse phase high performance liquid chromatography.

    PubMed

    Konda, Bharath; Tiwari, Ravi N; Fegade, Harshal

    2011-09-01

    Exemestane is an aromatase inhibitor used in the treatment of breast cancer. A selective stability-indicating reversed-phase high performance liquid chromatography (RP-HPLC) method has been developed which can separate and accurately quantitate low levels of exemestane. The stability-indicating capability of the method was demonstrated by adequate separation of exemestane and all the degradation product peaks from exemestane peak and also from each other in stability samples of exemestane. Chromatographic separation of exemestane and its degraded products were achieved by using isocratic elution at a flow rate of 1.0 mL/min on a C18 reverse phase column (Phenomenex, size: 250 × 4.60 mm, particle size 5 μm) at ambient temperature. The mobile phase used for the analysis was acetonitrile-water (60:40, %v/v) with UV visible detection at 242 nm. The proposed method was used to study the degradation behavior of drug under various stress conditions as per ICH recommended guidelines.

  13. Stability-Indicating HPLC Method for Simultaneous Determination of Chloramphenicol, Dexamethasone Sodium Phosphate and Tetrahydrozoline Hydrochloride in Ophthalmic Solution

    PubMed Central

    AlAani, Hashem; Alnukkary, Yasmin

    2016-01-01

    Purpose: A simple stability-indicating RP-HPLC assay method was developed and validated for quantitative determination of Chloramphenicol, Dexamethasone Sodium Phosphate and Tetrahydrozoline Hydrochloride in ophthalmic solution in the presence of 2-amino-1-(4-nitrophenyl)propane-1,3-diol, a degradation product of Chloramphenicol, and Dexamethasone, a degradation product of Dexamethasone Sodium Phosphate. Methods: Effective chromatographic separation was achieved using C18 column (250 mm, 4.6 mm i.d., 5 μm) with isocratic mobile phase consisting of acetonitrile - phosphate buffer (pH 4.0; 0.05 M) (30:70, v/v) at a flow rate of 1 mL/minute. The column temperature was maintained at 40°C and the detection wavelength was 230 nm. Results: The proposed HPLC procedure was statistically validated according to the ICH guideline, and was proved to be stability-indicating by resolution of the APIs from their forced degradation products. Conclusion: The developed method is suitable for the routine analysis as well as stability studies. PMID:27123429

  14. Determination of seven phenolic compounds in Rhizoma Sparganii by RP-HPLC.

    PubMed

    Wang, Xinsheng; Wu, Qi-nan; Wu, Yanfang; Wu, Chengying; Yue, Wei; Liang, Qiaoli

    2013-04-01

    A reversed-phase high-performance liquid chromatographic method was developed for the simultaneous quantification of seven phenolic compounds from Rhizoma Sparganii. The samples were separated on a Waters SunFire C18 column with a temperature of 30°C. Gradient elution was applied, using 0.8% acetic acid (solvent A) and methanol (solvent B) with a flow rate of 1.0 mL/min, and detection wavelength was 280 nm. The validation of the method included linearity, precision, repeatability, stability and recovery. The calibration curves showed good linear regression (R(2) > 0.9996) within the test range. The developed method indicated good precision and accuracy, with the overall intra-day and inter-day variation at less than 3%. The range of recoveries for the seven analytes was 95.34-100.06% with relative standard deviation < 3.08 %. The established method was successfully applied for the determination of seven phenolic compounds in 12 batches of Rhizoma Sparganii. The study may be useful in the quality evaluation of Rhizoma Sparganii, and can provide technical support for pharmacological and clinical research of related drugs.

  15. Methodology for a rapid and simultaneous determination of total cysteine, homocysteine, cysteinylglycine and glutathione in plasma by isocratic RP-HPLC.

    PubMed

    Ferin, Rita; Pavão, Maria Leonor; Baptista, José

    2012-12-12

    Alterations in the plasma aminothiols levels can be considered as important biomarkers for the diagnosis and screening of several human disorders, namely cardiovascular diseases. We aimed to optimize a rapid, sensitive and accurate RP-HPLC methodology with fluorescence detection, for the simultaneous determination of the total concentrations of cysteine, homocysteine, cysteinylglycine and glutathione in blood plasma, as well as its application to the evaluation of those thiols levels in plasma of a group of Azorean subjects. Aminothiols were reduced with tri-n-butylphosphine and derivatized with a thiol-specific fluorogenic reagent ammonium 7-fluorobenzo-2-oxa-1,3-diazole-4-sulphonate. The thiols adducts were separated by an isocratic elution on a Platinum EPS C18 analytical column (53mm×7mm I.D., 3μm) using a phosphate buffer containing 4% of acetonitrile as a mobile phase. Results indicated an excellent linearity for all the analytes over their respective concentration ranges with correlation coefficients (r(2)) ≥0.99. The LOD for the four plasma thiols was lower than 0.10μmol/L, while LOQ varied from 0.5 to 15μmol/L. For both intra- and inter-day precision, the RSD (%) values were lower than 1.9%, and the CV (%) values were found under 0.5%. The recovery ranged from 92% to 100% indicating a high degree of the method's accuracy. This method allows a simultaneous, complete analysis of the four plasma aminothiols and the internal standard in 6min. By reducing the total run time, a larger number of analysis can be performed daily.

  16. Simultaneous quantitative determination of nine active chemical compositions in traditional Chinese medicine Glycyrrhiza by RP-HPLC with full-time five-wavelength fusion method.

    PubMed

    Wu, Yin-Ping; Meng, Xian-Sheng; Bao, Yong-Rui; Wang, Shuai; Kang, Ting-Guo

    2013-01-01

    A new, simple, accurate and reliable full-time five-wavelength fusion method for the simultaneous separation and determination of nine active chemical compositions (liquiritin apioside, liquiritin, isoliquiritin apioside, ononin, isoliquiritin, liquiritigenin, calycosin, isoliquiritigenin, Glycyrrhizic acid monoammonium salt) in traditional Chinese medicine Glycyrrhiza was developed using reverse phase high-performance liquid chromatography (RP-HPLC) coupled with a diode-array detector (DAD). The chromatographic separation was performed on an Agilent TC-C18 column with gradient elution using 0.04% methanoic acid (A) and acetonitrile (B) at a flow rate of 1.0 mL min(-1) and UV detection at 248 nm, 250 nm, 276 nm, 362 nm, 370 nm. The standard curves were linear over the range of 2.1379-12.8272 μg for liquiritin apioside, 3.9299-23.5794 μg for liquiritin, 1.0432-6.2592 μg for isoliquiritin apioside, 0.8764-5.8584 μg for ononin, 1.0701-6.4205 μg for isoliquiritin, 1.3685-8.2111 μg for liquiritigenin, 0.3927-2.3563 μg for calycosin, 0.2498- 1.4986 μg for isoliquiritigenin, 2.0094-12.0564 μg for Glycyrrhizic acid monoammonium salt, respectively (r(2) > 0.9997). The recoveries and relative standard deviation (RSD) varied from 95.09% to 103.54% and 1.09% to 2.36%, respectively. The precision for all the analytes was less than 2.52%. The method indicated good performance in terms of precision, accuracy and linearity. The method enabled the simultaneous determination of nine active chemical compositions for quality control of Glycyrrhiza.

  17. A single-step extraction method for the determination of nicotine and cotinine in Jordanian smokers' blood and urine samples by RP-HPLC and GC-MS.

    PubMed

    Massadeh, Adnan M; Gharaibeh, Ahmad A; Omari, Khaled W

    2009-02-01

    A simple, rapid, reliable, and low cost one-step extraction method is developed and validated for the determination of nicotine and cotinine in human plasma and urine in smokers using reversed-phase high-performance liquid chromatography (RP-HPLC) and gas chromatography-mass spectrometry (GC-MS). The run times are 16 and 10 min for HPLC and GC-MS, respectively. The method is validated over a wide linear range of 1-5000 ng/mL with correlation coefficients being consistently greater than 0.9985. The criteria considered for validation are: limit of quantitation, linearity, accuracy, precision, recovery, specificity, and selectivity. This study is aimed to estimate the nicotine and cotinine in Jordanian smokers' blood and urine samples; to study the relationship between the concentration of nicotine in urine and plasma samples; and to investigate the effect of pH on the extraction of nicotine and cotinine in urine samples. In the presented study, one hundred blood and urine samples are collected from eighty smokers and twenty nonsmokers. Samples are taken from the same volunteer at the same time after each volunteer fills in a questionnaire. Results of nicotine concentrations in smokers' plasma are in the range of 181-3702 ng/mL with an average of 1263.1 ng/mL, whereas nicotine in urine samples is in the range of 1364-1972 ng/mL, with an average of 1618 ng/mL. Cotinine concentrations in smokers' plasma are in the range of 21-4420 ng/mL with an average of 379.4 ng/mL, whereas cotinine in urine is in the range of 6-3946 ng/mL with an average of 865 ng/mL. Statistical analysis indicates highly significant differences in nicotine and cotinine concentrations in smoker samples compared with nonsmoker samples (p<0.05).

  18. Simultaneous determination of piracetam and its four impurities by RP-HPLC with UV detection.

    PubMed

    Arayne, M Saeed; Sultana, Najma; Siddiqui, Farhan Ahmed; Mirza, Agha Zeeshan; Qureshi, Faiza; Zuberi, M Hashim

    2010-08-01

    A simple and rapid high-performance liquid chromatographic method for the separation and determination of piracetam and its four impurities, 2-oxopyrrolidin-1-yl)acetic acid, pyrrolidin-2-one, methyl (2-oxopyrrolidin-1-yl)acetate, and ethyl (2-oxopyrrolidin-1-yl)acetate, was developed. The separation was achieved on a reversed-phase C(18) Nucleosil column (25 cm x 0.46 cm, 10 microm). The mobile phase is composed of an aqueous solution containing 0.2 g/L of triethyl amine-acetonitrile (85:15, v/v). The pH of the mobile phase was adjusted to 6.5 with phosphoric acid at a flow rate of 1 mL/min at ambient temperature and UV detection at 205 nm. The developed method was found to give good separation between the pure drug and its four related substance. The polynomial regression data for the calibration plots showed good linear relationship in the concentration range of 50-10,000 ng/mL, 25-10,000 ng/mL, 45-10,000 ng/mL, 34-10,000 ng/mL, and 55-10,000 ng/mL, respectively, with r(2) = 0.9999. The method was validated for precision, accuracy, ruggedness, and recovery. The minimum quantifiable amounts were found to be 50 ng/mL of piracetam, 25 ng/mL of 2-oxopyrrolidin-1-yl)acetic acid, 45 ng/mL of pyrrolidin-2-one, 34 ng/mL of methyl (2-oxopyrrolidin-1-yl)acetate, and 55 ng/mL of ethyl (2-oxopyrrolidin-1-yl)acetate. Statistical analysis proves that the method is reproducible and selective for the estimation of piracetam as well as its related substance. As the method could effectively separate the drug from the related substances, it can be employed as a stability-indicating one. The proposed method shows high efficiency, allowing the separation of the main component piracetam from other impurities.

  19. Enantioseparation of Citalopram by RP-HPLC, Using Sulfobutyl Ether-β-Cyclodextrin as a Chiral Mobile Phase Additive

    PubMed Central

    Peng, Yangfeng; He, Quan Sophia; Cai, Jiang

    2016-01-01

    Enantiomeric separation of citalopram (CIT) was developed using a reversed phase HPLC (RP-HPLC) with sulfobutylether-β-cyclodextrin (SBE-β-CD) as a chiral mobile phase additive. The effects of the pH value of aqueous buffer, concentration of chiral additive, composition of mobile phase, and column temperature on the enantioseparation of CIT were investigated on the Hedera ODS-2 C18 column (250 mm × 4.6 mm × 5.0 um). A satisfactory resolution was achieved at 25°C using a mobile phase consisting of a mixture of aqueous buffer (pH of 2.5, 5 mM sodium dihydrogen phosphate, and 12 mM SBE-β-CD), methanol, and acetonitrile with a volumetric ratio of 21 : 3 : 1 and flow rate of 1.0 mL/min. This analytical method was evaluated by examining the precision (lower than 3.0%), linearity (regression coefficients close to 1), limit of detection (0.070 µg/mL for (R)-CIT and 0.076 µg/mL for (S)-CIT), and limit of quantitation (0.235 µg/mL for (R)-CIT and 0.254 µg/mL for (S)-CIT). PMID:26880921

  20. RP-HPLC method for simultaneous estimation of tenofovir disoproxil fumarate, lamivudine, and efavirenz in combined tablet dosage form

    PubMed Central

    Bhavsar, Dhara S.; Patel, Bhavini N.; Patel, Chhaganbhai N.

    2012-01-01

    Background: A simple, precise, accurate, and rapid reverse phase-high performance liquid chromatography (RP-HPLC) method with UV-Visible detector has been developed and subsequently validated for the simultaneous determination of tenofovir disoproxil fumarate (TDF), lamivudine (LAMI), and efavirenz (EFV) in their combined tablet dosage form. Materials and Methods: The separation was based on the use of a Kromasil C18 analytical column (150 × 4.6 mm, i.d., 5 μm). The mobile phase consisted of a mixture of 70 volumes of methanol and 30 volumes of 10 mM phosphate buffer (pH 5.0). The separation was carried out at 40°C temperature with a flow rate of 1 ml/min. Results: Quantitation was achieved with UV detection at 254 nm, with linear calibration curves at concentration ranges of 1–6 μg/ml for TDF and LAMI and 2–12 μg/ml for EFV. The recoveries obtained were 99.46–101.36% for LAMI, 99.57–101.42% for TDF, and 99.96–100.87 for EFV. Conclusion: The method was validated according to International conference of harmonisation guidelines in terms of accuracy, precision, specificity, robustness, limits of detection and quantitation, and other aspects of analytical validation. PMID:23781482

  1. Application of RP-HPLC-diode array detector after SPE to the determination of pesticides in pepper samples.

    PubMed

    Tuzimski, Tomasz

    2012-01-01

    The application of HPLC-diode array detector (DAD) after SPE for identification and quantitative analysis of pesticides in red and green pepper samples is demonstrated. An HPLC procedure on an RP column (C18) was developed for analysis of selected pesticides from different chemical groups: metamitron, metalaxyl, linuron, and prometryn. Average recoveries for C18 Polar Plus cartridges and solvents by the proposed RP-HPLC-DAD method after SPE are presented. Average recoveries from the spiked samples and the SDs were 22.5 +/- 2.2, 138.0 +/- 4.1, 78.6 +/- 2.8, and 109.2 +/- 2.3% for metamitron, metalaxyl, linuron, and prometryn, respectively, at concentrations of 7 microg/g in the plant material. The efficiency of the SPE procedure was evaluated using real food samples. The quantities of prometryn, linuron, metalaxyl, and metamitron determined were in the ranges of 0.02-2.24 microg/g (n = 24), 0.08-1.01 microg/g (n = 9), 1.61-2.28 microg/g (n=4), and 0.05-1.07 microg/g (n = 3), respectively, in plant material sampled in 2011. The method was validated for precision, repeatability, and accuracy.

  2. Determination of Vitamin B12 in meat products by RP-HPLC after enrichment and purification on an immunoaffinity column.

    PubMed

    Guggisberg, D; Risse, M C; Hadorn, R

    2012-02-01

    A quantitative method for the determination of Vitamin B12 in meat products by RP-HPLC and UV detection was developed and compared to the reference method (microbiological assay, MBA). Vitamin B12 was extracted with 50mM sodium acetate buffer in the presence of sodium cyanide. For the quantification of total Vitamin B12, it was necessary to release protein-bound Vitamin B12 by pepsin treatment. Cyanocobalamin was detected as total Vitamin B12 after purification and enrichment on an immunoaffinity column. The calibration with five concentrations of Vitamin B12 was linear with a regression coefficient r2>0.99. The method was validated at three different concentration levels (5-15 ng/g) with salami showing good recovery rates between 80 and 108% and low relative standard deviations between 1.50 and 7.26% (n = 6). The detection limit was found to be 2 ng/g. The Vitamin B12 levels of 50 meat products measured by the developed procedure were similar or significantly lower than those determined by the MBA.

  3. RP-HPLC Separation of Isomeric Withanolides: Method Development, Validation and Application to In situ Rat Permeability Determination.

    PubMed

    Yaseen Malik, Mohd; Taneja, Isha; Raju, Kanumuri Siva Rama; Rahaman Gayen, Jiaur; Singh, Sheelendra Pratap; Sangwand, Neelam S; Wahajuddin, Muhammad

    2017-04-12

    Withanolides are the group of active chemical constituents of Withania somnifera (L.) Dunal. Withaferin A, withanolide A and withanone presents three of the biologically most active constituents of this herb. These steroidal lactones are isomers of each other and thus, pose significant difficulty in their separation. In present study, a simple, specific and reliable RP-HPLC method has been developed and validated for their separation and simultaneous quantification. Separation was carried out on Lichrocart Purospher STAR RP-18e column (250 × 4.5 mm, 5 µm) using mobile phase, methanol and 0.01 M ammonium acetate buffer (pH 5) in the ratio 60:40, v/v. The calibration curves were linear (r2 > 0.99) for all the three compounds across concentration range of 1.56-50 µg/mL. The lower limit of quantification for all the analytes was 1.56 µg/mL. The intra-day and inter-day accuracy was between 88.65% and 110.66% and coefficient of variation was between 0.55 and 10.12. The analytes were stable under different storage conditions. The developed method was successfully applied to analyze the samples for simultaneous determination of permeability of the three withanolides in rats using in situ single-pass intestinal perfusion model. Withanolide A and withanone were found to be high permeability compounds while withaferin A could not be detected.

  4. Enantioseparation of Citalopram by RP-HPLC, Using Sulfobutyl Ether-β-Cyclodextrin as a Chiral Mobile Phase Additive.

    PubMed

    Peng, Yangfeng; He, Quan Sophia; Cai, Jiang

    2016-01-01

    Enantiomeric separation of citalopram (CIT) was developed using a reversed phase HPLC (RP-HPLC) with sulfobutylether-β-cyclodextrin (SBE-β-CD) as a chiral mobile phase additive. The effects of the pH value of aqueous buffer, concentration of chiral additive, composition of mobile phase, and column temperature on the enantioseparation of CIT were investigated on the Hedera ODS-2 C18 column (250 mm × 4.6 mm × 5.0 um). A satisfactory resolution was achieved at 25°C using a mobile phase consisting of a mixture of aqueous buffer (pH of 2.5, 5 mM sodium dihydrogen phosphate, and 12 mM SBE-β-CD), methanol, and acetonitrile with a volumetric ratio of 21 : 3 : 1 and flow rate of 1.0 mL/min. This analytical method was evaluated by examining the precision (lower than 3.0%), linearity (regression coefficients close to 1), limit of detection (0.070 µg/mL for (R)-CIT and 0.076 µg/mL for (S)-CIT), and limit of quantitation (0.235 µg/mL for (R)-CIT and 0.254 µg/mL for (S)-CIT).

  5. A Validated RP HPLC-PAD Method for the Determination of Hederacoside C in Ivy-Thyme Cough Syrup

    PubMed Central

    Khdair, Ayman; Mohammad, Mohammad K.; Tawaha, Khaled; Al-Hamarsheh, Eman; AlKhatib, Hatim S.; Al-khalidi, Bashar; Bustanji, Yasser; Najjar, Samer; Hudaib, Mohammad

    2010-01-01

    A simple reversed phase high-performance liquid chromatographic (RP-HPLC) method coupled with a photodiode array detector (PAD) has been developed and validated for the analysis of hederacoside C, the marker of ivy plant, in Ivy-Thyme cough syrup. Separation of hederacoside C was achieved using a Phenomenex-Gemini C18 column isothermally at 40°C. A mobile phase system constituted of solvent A (water: acetonitrile: orthophosphoric acid (85%), 860 : 140 : 2 v/v) and solvent B (acetonitrile: orthophosphoric acid (85%), 998 : 2 v/v) was used, at gradient conditions, at a flow rate of 1.5 mL/min. Analysis was performed using UV-detection (205 nm). The method was linear over the range (0.03–0.15) mg/mL of hederacoside C (r = 0.9992). Repeatability and intermediate precision were acceptable (RSD <2%). Limits of detection (LOD) and quantitation (LOQ) were 0.011 and 0.032 mg/mL, respectively. Percentage recovery was found to lie between 99.69% and 100.90% (RSD <2%). The method was also proved to be specific (peak-purity coefficient = 0.996). PMID:20862201

  6. Validated RP-HPLC method for simultaneous determination and quantification of chlorpheniramine maleate, paracetamol and caffeine in tablet formulation.

    PubMed

    Acheampong, Akwasi; Gyasi, Wilfred Owusu; Darko, Godfred; Apau, Joseph; Addai-Arhin, Sylvester

    2016-01-01

    Chlorpheniramine maleate-paracetamol-caffeine tablet formulation is one of the common over-the-counter drugs used for the treatment of cold and cough. A reversed-phase high-performance liquid-chromatography method has been successfully developed for the simultaneous determination of chlorpheniramine maleate, paracetamol and caffeine in a drug formulation. The RP-HPLC method employed a Phenomenex C18 reversed phase column (Luna 5µ, 250 × 4.6 mm) with an isocratic mixture of methanol and 0.05 M dibasic phosphate buffer pH 4.0 in the ratio of (30:70; v/v) as the mobile phase. The column temperature was kept at 30 °C. The flow rate was 1.0 mL/min and detection was by means of a UV detector at wavelength of 215 nm. All the active components were successfully eluted with mean retention times of 2.4, 4.2, 7.2 min for chlorpheniramine maleate, paracetamol and caffeine respectively. The method was found to be linear (R(2) > 0.99), precise (RSD < 2.0 %), accurate (recoveries 97.9-102.8 %), specific, simple, sensitive, rapid and robust. The validated method can be used in routine quality control analysis of fixed dose combination tablets containing chlorpheniramine maleate, paracetamol and caffeine without any interference by excipients.

  7. Validated RP-HPLC method for the simultaneous analysis of gemcitabine and LY-364947 in liposomal formulations.

    PubMed

    Bansal, Shyam S; Celia, Christian; Ferrati, Silvia; Zabre, Erika; Ferrari, Mauro; Palapattu, Ganesh; Grattoni, Alessandro

    2013-08-01

    Combined use of gemcitabine (Gem) and LY-364947 (LY), a TGF-β1 receptor inhibitor, has shown promise for the treatment of fibrotic pancreatic cancer, by reducing collagen production and improving tumor drug penetration. The preparation and optimization of novel Gem and LY formulations, including co-encapsulation in liposomes, require a validated method for the simultaneous quantification of both drugs, a method that had yet to be developed. Here we demonstrate an RP-HPLC protocol for the simultaneous detection of Gem and LY at 266 and 228 nm with retention times of 3.37 and 11.34 mins, respectively. The method, which uses a C18 column and a KH2PO4 (10 mM)-methanol mobile phase, was validated for linearity, precision, accuracy, limits of detection, and robustness. Co-loaded liposomes with both Gem and LY (Gem/LY liposomes) were developed to investigate the protocol applicability to pharmacokinetic analysis and formulation characterization. The method specificity was evaluated in presence of liposomal components in fetal bovine serum (FBS). Finally, the method was demonstrated by quantifying Gem/LY liposomal encapsulation efficiency and concentration liposomes-spiked FBS.

  8. A validated RP-HPLC method to investigate finasteride in human skin after in vitro topically applying vesicular nanocarrier.

    PubMed

    Zheng, Feiyue; Rao, Yuefeng; Lou, Yan; Lu, Xiaoyang

    2014-05-01

    The pharmacotherapeutic efficiency of topical drug delivery systems is mainly dominated by the skin distribution of therapeutic agents. In this work, a sensitive, rapid and fully-validated reversed-phase high performance liquid chromatography (RP-HPLC) method was developed to determine finasteride in human cadaver skin after different vesicular formulations were applied. Drug in different depth of skin layers were measured with an EclipseXDB-C18 column. The mobile phase consisted of 75% (v/v) methanol containing 0.2% phosphoric acid buffered to pH 3.0 with triethylamine under isocratic conditions. The system was operated at 40°C and the mobile phase flow rate was set at 1 mL/min. The standard-calibration curve was linear within range of 5 to 200 ng/ml with correlation coefficient 0.9996. The intra-assay precision was less than 3.9% while the inter-assay precision was less than 7.1% with the bias range of -8.6 to 4.1%. This method was found to be specific, accurate, and sensitive and was successfully used to determine the accumulation of finasteride after in-vitro percutaneous delivery by liposomal or ethosomal drug delivery nanocarriers.

  9. Validation and Uncertainty Estimation of an Ecofriendly and Stability-Indicating HPLC Method for Determination of Diltiazem in Pharmaceutical Preparations

    PubMed Central

    Sadeghi, Fahimeh; Navidpour, Latifeh; Bayat, Sima; Afshar, Minoo

    2013-01-01

    A green, simple, and stability-indicating RP-HPLC method was developed for the determination of diltiazem in topical preparations. The separation was based on a C18 analytical column using a mobile phase consisted of ethanol: phosphoric acid solution (pH = 2.5) (35 : 65, v/v). Column temperature was set at 50°C and quantitation was achieved with UV detection at 240 nm. In forced degradation studies, the drug was subjected to oxidation, hydrolysis, photolysis, and heat. The method was validated for specificity, selectivity, linearity, precision, accuracy, and robustness. The applied procedure was found to be linear in diltiazem concentration range of 0.5–50 μg/mL (r2 = 0.9996). Precision was evaluated by replicate analysis in which % relative standard deviation (RSD) values for areas were found below 2.0. The recoveries obtained (99.25%–101.66%) ensured the accuracy of the developed method. The degradation products as well as the pharmaceutical excipients were well resolved from the pure drug. The expanded uncertainty (5.63%) of the method was also estimated from method validation data. Accordingly, the proposed validated and sustainable procedure was proved to be suitable for routine analyzing and stability studies of diltiazem in pharmaceutical preparations. PMID:24163778

  10. Molecular and Quantum Mechanical Study for the Separation of Cefprozil in the Presence of Its Alkaline Degradation Product Using RP-HPLC with UV Detection.

    PubMed

    Attia, Khalid A M; Nassar, Mohammed W I; El-Zeiny, Mohamed B; Serag, Ahmed

    2017-03-01

    A reversed-phase HPLC method (RP-HPLC) with UV detection was developed and validated for the quantitative determination of cefprozil, a second-generation cephalosporin. Due to β-lactam ring instability under alkaline conditions, this RP-HPLC method was applied for the determination of cefprozil in the presence of its possible degradation product. The interactions that govern the separation process with stationary phase were investigated at both molecular and quantum mechanical levels. Moreover, electrostatic potential maps were generated to determine the sites of interaction with mobile phase. The suggested method was validated in compliance with International Conference on Harmonization guidelines and successfully applied for the determination of cefprozil in its commercial pharmaceutical formulation.

  11. Simultaneous determination of chloramphenicol, dexamethasone and naphazoline in ternary and quaternary mixtures by RP-HPLC, derivative and wavelet transforms of UV ratio spectra

    NASA Astrophysics Data System (ADS)

    Hoang, Vu Dang; Hue, Nguyen Thu; Tho, Nguyen Huu; Nguyen, Hue Minh Thi

    2015-03-01

    The application of chemometrics-assisted UV spectrophotometry and RP-HPLC to the simultaneous determination of chloramphenicol, dexamethasone and naphazoline in ternary and quaternary mixtures is presented. The spectrophotometric procedure is based on the first-order derivative and wavelet transforms of ratio spectra using single, double and successive divisors. The ratio spectra were differentiated and smoothed using Savitzky-Golay filter; whereas wavelet transform realized with wavelet functions (i.e. db6, gaus5 and coif3) to obtain highest spectral recoveries. For the RP-HPLC procedure, the separation was achieved on a ZORBAX SB-C18 (150 × 4.6 mm; 5 μm) column at ambient temperature and the total run time was less than 7 min. A mixture of acetonitrile - 25 mM phosphate buffer pH 3 (27:73, v/v) was used as the mobile phase at a flow rate of 1.0 mL/min and the effluent monitored by measuring absorbance at 220 nm. Calibration graphs were established in the range 20-70 mg/L for chloramphenicol, 6-14 mg/L for dexamethasone and 3-8 mg/L for naphazoline (R2 > 0.990). The RP-HPLC and ratio spectra transformed by a combination of derivative-wavelet algorithms proved to be able to successfully determine all analytes in commercial eye drop formulations without sample matrix interference (mean percent recoveries, 97.4-104.3%).

  12. Development of a rapid RP-HPLC method for the determination of clonazepam in human plasma.

    PubMed

    Bares, Isabelle Forfar; Pehourcq, Fabienne; Jarry, Christian

    2004-11-19

    A rapid and sensitive high-performance liquid chromatography method with UV detection was developed for the determination of clonazepam in human plasma using 3-methylclonazepam, as internal standard. A one-step extraction of both compounds was performed with a mixture of hexane/ethyl acetate (90:10, v/v). The HPLC analysis was carried out on a Nova Pak((R)) C(18) reversed-phase column with a mobile phase of acetonitrile-0.01 M sodium acetate adjusted to pH 7 with dilute acetic acid (40:60, v/v). A linear response was observed over the concentration range 5-100 ng/mL. Intra- and inter-day assay precision and accuracy fulfilled the international requirements. The lower limit of quantification was 5 ng/mL without interference of endogenous components. For analytical purpose, the stability of clonazepam in bidistilled water and plasma has been studied. A rapid degradation was noticed when clonazepam was stored in bidistilled water at the daylight following a first-order kinetic rate with a 87 min half life whereas no significant degradation was observed in plasma. This method was applied to measure plasma concentrations of clonazepam either in patients receiving therapeutic doses or in poisoning cases.

  13. RP-HPLC Method for Simultaneous Estimation of Nitazoxanide and Ofloxacin in Tablets

    PubMed Central

    Sharma, S.; Bhandari, A.; Choudhary, V. R.; Rajpurohit, H.; Khandelwal, P.

    2011-01-01

    A reverse phase high performance liquid chromatography method was developed for simultaneous estimation of nitazoxanide and ofloxacin in tablet formulation. The separation and quantification was achieved by Hiq Sil C18V Size 4.6 mm Ø *250 mm column in isocratic mode, with mobile phase consisting of acetonitrile-methanol-0.4 M citric acid, (60:30:10, v/v/v). Citric acid used to stabilize nitazoxanide and ofloxacin in mobile phase. The mobile phase was pumped at a rate of 0.6 ml/min and the detection was carried out at 304 nm. The retention time of ofloxacin and nitazoxanide was found to be 3.122 and 5.902 min, respectively. The method was validated for linearity, accuracy, and precision. Linearity for ofloxacin and nitazoxanide were in the range 2-36 μg/ml and 5-90 μg/ml, respectively. The developed method was found to be accurate, precise and selective for simultaneous estimation of ofloxacin and nitazoxanide in tablets. PMID:22131628

  14. Simultaneous determination of imipramine hydrochloride and chlordiazepoxide in pharmaceutical preparations by spectrophotometric, RP-HPLC, and HPTLC methods.

    PubMed

    Patel, Sejal K; Patel, Natvarlal J

    2010-01-01

    A binary mixture of imipramine HCl and chlordiazepoxide was determined by three different methods. The first involved determination of imipramine HCl and chlordiazepoxide using the first derivative spectrophotometric technique at 219 and 231.5 nm over the concentration ranges of 1-20 and 2-24 microg/mL with mean accuracies of 99.47 +/- 0.78 and 101.43 +/- 1.20%, respectively. The second method utilized RP-HPLC with methanol-acetonitrile-0.065 M ammonium acetate buffer (45 + 25 + 30, v/v/v, pH adjusted to 5.6 +/- 0.02 with phosphoric acid) as the mobile phase pumped at a flow rate of 1.0 mL/min. Quantification was achieved using UV detection at 240 nm over concentration ranges of 0.25-4.0 and 0.1-1.6 microg/mL, with mean accuracies of 101.17 +/- 0.56 and 100.67 +/- 0.40% for imipramine HCl and chlordiazepoxide, respectively. The third method was HPTLC with carbon tetrachloride-acetone-triethylamine (pH 8.3; 6 + 3 + 0.3, v/v/v) as the mobile phase. Quantification was achieved with UV detection at 240 nm over concentration ranges of 50-600 and 20-240 ng/spot with mean accuracies of 99.51 +/- 0.59 and 100.59 +/- 0.84% for imipramine HCl and chlordiazepoxide, respectively. The suggested procedures were checked using prepared mixtures, and were successfully applied for the analysis of pharmaceutical preparations. The accuracy and precision of the methods were confirmed when the standard addition technique was applied. The results obtained by applying the proposed methods were statistically analyzed.

  15. RP-HPLC/MS/MS Analysis of the Phenolic Compounds, Antioxidant and Antimicrobial Activities of Salvia L. Species

    PubMed Central

    Tohma, Hatice; Köksal, Ekrem; Kılıç, Ömer; Alan, Yusuf; Yılmaz, Mustafa Abdullah; Gülçin, İlhami; Bursal, Ercan; Alwasel, Saleh H.

    2016-01-01

    The identification and quantification of the phenolic contents of methanolic extracts of three Salvia L. species namely S. brachyantha (Bordz.) Pobed, S. aethiopis L., and S. microstegia Boiss. and Bal. were evaluated using reverse phase high performance liquid chromatography, UV adsorption, and mass spectrometry (RP-HPLC/MS). In order to determine the antioxidant capacity of these species, cupric ions (Cu2+) reducing assay (CUPRAC) and ferric ions (Fe3+) reducing assay (FRAP) were performed to screen the reducing capacity and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay was employed for evaluation of the radical scavenging activity for both solvents. In further investigation, the antimicrobial activities of Salvia species were tested using the disc diffusion method against three Gram-positive and four Gram-negative microbial species, as well as three fungi species. The results showed that there is a total of 18 detectable phenols, the most abundant of which was kaempferol in S. microstegia and rosmarinic acids in S. brachyantha and S aethiopis. The other major phenols were found to be apigenin, luteolin, p-coumaric acid, and chlorogenic acid. All species tested showed moderate and lower antioxidant activity than standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and ascorbic acid. The ethanolic extracts of Salvia species revealed a wide range of antimicrobial activity. S. brachyantha and S. microstegia showed the highest antimicrobial activities against B. subtilis, whereas S. aethiopis was more effective on Y. lipolytica. None of the extracts showed anti-fungal activity against S. cerevisiae. Thus these species could be valuable due to their bioactive compounds. PMID:27775656

  16. Simultaneous estimation of phenolic acids in sea buckthorn (Hippophaë rhamnoides) using RP-HPLC with DAD.

    PubMed

    Arimboor, Ranjith; Kumar, K Sarin; Arumughan, C

    2008-05-12

    A RP-HPLC-DAD method was developed and validated for the simultaneous analysis of nine phenolic acids including gallic acid, protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, salicylic acid, p-coumaric acid, cinnamic acid, caffiec acid and ferulic acid in sea buckthorn (SB) (Hippophaë rhamnoides) berries and leaves. The method was validated in terms of linearity, LOD, precision, accuracy and recovery and found to be satisfactory. Phenolic acid derivatives in anatomical parts of SB berries and leaves were separated into free phenolic acids, phenolic acids bound as esters and phenolic acids bound as glycosides and profiled in HPLC. Berry pulp contained a total of 1068 mg/kg phenolic acids, of which 58.8% was derived from phenolic glycosides. Free phenolic acids and phenolic acid esters constituted 20.0% and 21.2%, respectively, of total phenolic acids in SB berry pulp. The total phenolic acid content in seed kernel (5741 mg/kg) was higher than that in berry pulp and seed coat (Table 2). Phenolic acids liberated from soluble esters constituted the major fraction of phenolic acids (57.3% of total phenolic acids) in seed kernel. 8.4% and 34.3% of total phenolic acids in seed kernel were, respectively contributed by free and phenolic acids liberated from glycosidic bonds. The total soluble phenolic acids content in seed coat (448 mg/kg) was lower than that in seed kernel and pulp (Table 2). Proportion of free phenolic acids in total phenolic acids in seed coat was higher than that in seed kernel and pulp. Phenolic acids bound as esters and glycosides, respectively contributed 49.1% and 20.3% of total phenolic acids in seed coat. The major fraction (approximately 70%) of phenolic acids in SB berries was found to be concentrated in the seeds. Gallic acid was the predominant phenolic acid both in free and bound forms in SB berry parts and leaves.

  17. A validated stability-indicating liquid chromatographic method for determination of process related impurities and degradation behavior of Irbesartan in solid oral dosage.

    PubMed

    Goswami, Nishant

    2014-01-01

    The present work describes the development and validation of a stability-indicating RP-HPLC method for the estimation of degradation and process related impurities of Irbesartan, namely Impurity-1, Impurity-2, Impurity-3 and Impurity-4. The developed LC method was validated with respect to specificity, limit of detection and quantification, linearity, precision, accuracy and robustness. The chromatographic separation was achieved on Hypersil Octadecylsilyl (4.6 mm × 150 mm, 3 μm) column by using mobile phase containing a gradient mixture of solvent A (0.55% v/v ortho-phosphoric acid, pH adjusted to 3.2 with triethyl amine) and B (95:5 v/v mixture of acetonitrile and solvent A) at a flow rate of 1.2 mL/min. The detection was carried out at a wavelength of 220 nm. During method validation parameter such as precision, linearity, accuracy, specificity, limit of detection and quantification were evaluated, which remained within acceptable limits. HPLC analytical method is linear, accurate, precise, robust and specific, being able to separate the main drug from its degradation products. The degradation products were well-resolved from the main peak and its impurities, thus proving the stability-indicating power of the method. The method is stability-indicating in nature and can be used for routine analysis of production samples and to check the stability of the Irbesartan HCl tablets.

  18. Isolation, Characterization, Crystal Structure Elucidation of Two Flavanones and Simultaneous RP-HPLC Determination of Five Major Compounds from Syzygium campanulatum Korth.

    PubMed

    Memon, Abdul Hakeem; Ismail, Zhari; Al-Suede, Fouad Saleih Resq; Aisha, Abdalrahim F A; Hamil, Mohammad Shahrul Ridzuan; Saeed, Mohammed Ali Ahmed; Laghari, Madeeha; Majid, Amin Malik Shah Abdul

    2015-08-04

    Two flavanones named (2S)-7-Hydroxy-5-methoxy-6,8-dimethyl flavanone (1), (S)-5,7-dihydroxy-6,8-dimethyl-flavanone (2), along with known chalcone, namely, (E)-2',4'- dihydroxy-6'-methoxy-3',5'-dimethylchalcone (3) and two triterpenoids, namely, betulinic and ursolic acids (4 and 5), were isolated from the leaves of Syzygium campanulatum Korth (Myrtaceae). The structures of compounds (1 and 2) were determined on the basis of UV-visible, FTIR, NMR spectroscopies and LC-EIMS analytical techniques. Furthermore, new, simple, precise, selective, accurate, highly sensitive, efficient and reproducible RP-HPLC method was developed and validated for the quantitative analysis of the compounds (1-5) from S. campanulatum plants of five different age. RP-HPLC method was validated in terms of specificity, linearity (r2 ≤ 0.999), precision (2.0% RSD), and recoveries (94.4%-105%). The LOD and LOQ of these compounds ranged from 0.13-0.38 and 0.10-2.23 μg·mL-1, OPEN ACCESS respectively. Anti-proliferative activity of isolated flavanones (1 and 2) and standardized extract of S. campanulatum was evaluated on human colon cancer (HCT 116) cell line. Compounds (1 and 2) and extract revealed potent and dose-dependent activity with IC50 67.6, 132.9 and 93.4 μg·mL-1, respectively. To the best of our knowledge, this is the first study on isolation, characterization, X-ray crystallographic analysis of compounds (1 and 2) and simultaneous RP-HPLC determination of five major compounds (1-5) from different age of S. campanulatum plants.

  19. Development and validation of a novel stability-indicating reversed-phase high-performance liquid chromatography method for assay of loratadine and determination of its related compounds.

    PubMed

    Lu, Jun; Wei, Yu-Chien; Markovich, Robert J; Rustum, Abu M

    2010-01-01

    Loratadine is an important active pharmaceutical ingredient used in a wide variety of prescription and over-the-counter products for the treatment and relief of allergy symptoms. A novel stability-indicating gradient ion-pair RP-HPLC method for assay of loratadine and determination of both of its degradation compounds and process impurities has been developed. This method can separate loratadine from its eight structurally related compounds; it can also separate all of the related compounds from each other in less than 20 min. The stability-indicating capability of this method has been demonstrated by analyzing aged stability samples of loratadine. A 15 cm x 4.6 mm id YMC-Pack Pro C18 HPLC column was the primary column and a 15 cm x 4.6 mm id SunFire C18 column has been identified as an alternate (truly equivalent) column for this method. This gradient method uses mobile phases consisting of acetonitrile and an aqueous solution of 10 mM sodium acetate and 5 mM sodium dodecyl sulfate at pH 5.5. The new HPLC method was validated according to International Conference on Harmonization guidelines and proved to be suitable for routine QC use.

  20. Determination of n-octanol/water partition coefficient for DDT-related compounds by RP-HPLC with a novel dual-point retention time correction.

    PubMed

    Han, Shu-ying; Qiao, Jun-qin; Zhang, Yun-yang; Yang, Li-li; Lian, Hong-zhen; Ge, Xin; Chen, Hong-yuan

    2011-03-01

    n-Octanol/water partition coefficients (P) for DDTs and dicofol were determined by reversed-phase high performance liquid chromatography (RP-HPLC) on a C(18) column using methanol-water mixture as mobile phase. A dual-point retention time correction (DP-RTC) was proposed to rectify chromatographic retention time (t(R)) shift resulted from stationary phase aging. Based on this correction, the relationship between logP and logk(w), the logarithm of the retention factor extrapolated to pure water, was investigated for a set of 12 benzene homologues and DDT-related compounds with reliable experimental P as model compounds. A linear regression logP=(1.10±0.04) logk(w) - (0.60±0.17) was established with correlation coefficient R(2) of 0.988, cross-validated correlation coefficient R(cv)(2) of 0.983 and standard deviation (SD) of 0.156. This model was further validated using four verification compounds, naphthalene, biphenyl, 2,2-bis(4-chlorophenyl)-1,1-dichloroethane (p,p'-DDD) and 2,2-bis(4-chlorophenyl)-1,1-dichloroethene (p,p'-DDE) with similar structure to DDT. The RP-HPLC-determined P values showed good consistency with shake-flask (SFM) or slow-stirring (SSM) results, especially for highly hydrophobic compounds with logP in the range of 4-7. Then, the P values for five DDT-related compounds, 2-(2-chlorophenyl)-2-(4-chlorophenyl)-1,1,1-trichloroethane (o,p'-DDT), 2-(2-chlorophenyl)-2-(4-chlorophenyl)-1,1-dichloroethane (o,p'-DDD), 2-(2-chlorophenyl)-2-(4-chlorophenyl)-1,1-dichloroethene (o,p'-DDE), and 2,2,2-trichloro-1,1-bis(4-chlorophenyl)ethanol (dicofol) and its main degradation product 4,4'-dichlorobenzophenone (p,p'-DBP) were evaluated by the improved RP-HPLC method for the first time. The excellent precision with SD less than 0.03 proved that the novel DP-RTC protocol can significantly increases the determination accuracy and reliability of P by RP-HPLC.

  1. Comparative studies on performance of CCC and preparative RP-HPLC in separation and purification of steroid saponins from Dioscorea zingiberensis C.H.Wright.

    PubMed

    Zhang, Xinxin; Liang, Jinru; Zhang, Yongmin; Liu, Jianli; Sun, Wenji; Ito, Yoichiro

    2015-03-01

    Steroid saponins from Dioscorea zingiberensis C.H.Wright were separated for the first time using two chromatographic methods for comparison: counter-current chromatography (CCC) coupled with evaporative light scattering detector (ELSD) and preparative reversed phase high-performance liquid chromatography (RP-HPLC) with an ultraviolet detector. Ethyl acetate-n-butanol-methanol-water (4:1:2:4, v/v) was chosen as the two-phase solvent system for CCC, while the acetonitrile-water (25:75 for the first step and15:85 for the second step, v/v) was used as the mobile phase in the preparative RP-HPLC. The following five steroid saponins were purified by theses two chromatographic methods, in one-step operation by CCC and by two-step operation in preparative RP-HPLC: 1) 26-O-β-D- glucopyranosyl-(25R)-furost-5-en-3β, 22ζ, 26-triol-3-O-[β-D-glucopyranosyl-(1→3)-β-D-glucopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (compound A), 2) 26-O-β-D-glucopyranosyl-(25R)-furost-5-en-3β, 22ζ, 4) 26-triol-3-O-[β-D-glucopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranoside (compound B), 3) 26-O-β-D-glucopyranosyl-(25R)-furost-5-en-3β, 22ζ, 26-triol-3-O-[α-L-rhamnopyranosyl-(1→4)]-β-D-glucopyranoside (compound C), 4) 26-O-β-D-glucopyranosyl-(25R)-furost-5, 20(22)-diene-3β, 26-diol-3-O-{α-L-rhamnopyranosyl-(1→4)-[β-D-glucopyranosyl-(1→3)-β-D-glucopyranosyl-(1→2)]}-β-D-glucopyranoside (compound D) and 5) 26-O-β-D-glucopyranosyl-(25R)-furost-5, 20(22)-diene-3β, 26-diol-3-O-[β-D-glucopyranosyl-(1→4)-α-L-rhamnopyranosy-(1→2)]-β-D-glucopyranoside (compound E). The purities of these five steroid saponins separated by both methods were over 95%, and structural identification of these compounds was performed by ESI-MS, and (13)C NMR. Comparison of these two established approaches revealed that CCC required a longer separation time but with less solvent consumption, whereas preparative RP-HPLC gave a shorter separation time

  2. Stability-Indicating HPLC Method for the Simultaneous Determination of HIV Tablet Containing Emtricitabine, Tenofovir Disoproxil Fumarate, and Rilpivirine Hydrochloride in Pharmaceutical Dosage Forms.

    PubMed

    Venkatesan, S; Kannappan, N; Mannemala, Sai Sandeep

    2014-01-01

    A simple, accurate, rapid, and stability-indicating RP-HPLC method for a combination of tenofovir disoproxil fumarate, emtricitabine, and rilpivirine has been developed and subsequently validated in commercial tablets. The proposed HPLC method utilizes Phenomenex Gemini C18 column (150 mm × 4.6 mm i.d., 5 µm) and mobile phase consisting of MeCN, potassium dihydrogen phosphate buffer (20 mM, pH 3.3), and triethylamine 58.72 : 41.23 : 0.05 (v/v) at a flow rate of 1.7 mL/min. Quantitation was achieved with UV detection at 270 nm. The method was validated in terms of accuracy, precision, linearity, limits of detection, limits of quantitation, and robustness. This optimized method has been successively applied to pharmaceutical formulation and no interference from the tablet excipients was found. TDF, EMT, and RPV and their combination drug product were subjected to acid, base, neutral hydrolysis, oxidation, dry heat, and photolytic stress conditions and the stressed samples were analyzed by the proposed method. As the proposed LC method could effectively separate the drugs from its degradation products, it can be employed as stability-indicating method for the determination of instability of these drugs in bulk and commercial tablets.

  3. Validation of a RP-HPLC-DAD Method for Chamomile (Matricaria recutita) Preparations and Assessment of the Marker, Apigenin-7-glucoside, Safety and Anti-Inflammatory Effect

    PubMed Central

    Miguel, Felipe Galeti; Cavalheiro, Amanda Henriques; Spinola, Nathália Favaretto; Ribeiro, Diego Luis; Barcelos, Gustavo Rafael Mazzaron; Antunes, Lusânia Maria Greggi; Hori, Juliana Issa; Marquele-Oliveira, Franciane; Rocha, Bruno Alves; Berretta, Andresa Aparecida

    2015-01-01

    Chamomile is a medicinal plant, which presents several biological effects, especially the anti-inflammatory effect. One of the compounds related to this effect is apigenin, a flavonoid that is mostly found in its glycosylated form, apigenin-7-glucoside (APG), in natural sources. However, the affectivity and safety of this glycoside have not been well explored for topical application. In this context, the aim of this work was to develop and validate a reversed-phase high-performance liquid chromatography (RP-HPLC-DAD) method to quantify APG in chamomile preparations. Additionally, the safety and the anti-inflammatory potential of this flavonoid were verified. The RP-HPLC-DAD method was developed and validated with linearity at 24.0–36.0 μg/mL range (r = 0.9994). Intra- and interday precision (RSD) were 0.27–2.66% and accuracy was 98.27–101.21%. The validated method was applied in the analysis of chamomile flower heads, glycolic extract, and Kamillen cream, supporting the method application in the quality control of chamomile preparations. Furthermore, the APG safety was assessed by MTT cytotoxicity assay and mutagenic protocols and the anti-inflammatory activity was confirmed by a diminished TNF-α production showed by mice macrophages treated with APG following LPS treatment. PMID:26421053

  4. A Rapid, Validated RP-HPLC Method for the Simultaneous Determination of Cleaning Validation and Cross-Contamination of 12 Beta-Lactam Compounds.

    PubMed

    Trivedi, Harshal Kanubhai; Kshtri, Nayan; Patel, Mukesh C

    2013-01-01

    The present work reports a rapid reversed-phase high-performance liquid chromatography (RP-HPLC) method for the simultaneous determination of 12 beta-lactam components for cleaning validation and cross-contamination. A strategic experimental approach was implemented for the method development. The desired chromatographic separation was achieved on a Symmetry C18 (4.6 X 75 mm, 3.5 μm) column using gradient elution. The optimized mobile phase consisted of the buffer tetrabutylammonium hydroxide pH-6.8 and acetonitrile. The eluted compounds were monitored at 215 nm and 254 nm wavelength using a photodiode array detector. The developed method separated 12-beta-lactam compounds from each other within a run time of 50 min. The method is effective for the determination of cross-contamination of penicillin and cephalosporin production blocks. The present method is specific and a lower limit of quantification was determined on the basis of the signal-to-noise ratio method; it is 1 μg/mL for all components. The developed RP-HPLC method was validated according to the International Conference on Harmonization (ICH) guidelines.

  5. Simultaneous HPTLC and RP-HPLC methods for determination of bumadizone in the presence of its alkaline-induced degradation product.

    PubMed

    Ali, Nouruddin W; ZaaZaa, Hala A; Abdelkawy, M; Magdy, Maimana A

    2012-10-01

    Accurate, selective, sensitive and precise HPTLC-densitometric and RP-HPLC methods were developed and validated for determination of bumadizone calcium semi-hydrate in the presence of its alkaline-induced degradation product and in pharmaceutical formulation. Method A uses HPTLC-densitometry, depending on separation and quantitation of bumadizone and its alkaline-induced degradation product on TLC silica gel 60 F(254) plates, using hexane-ethyl acetate-glacial acetic acid (8:2:0.2, v/v/v) as a mobile phase followed by densitometric measurement of the bands at 240 nm. Method B comprises RP-HPLC separation of bumadizone and its alkaline-induced degradation product using a mobile phase consisting of methanol-water-acetonitrile (20:30:50, v/v/v) on a Phenomenex C(18) column at a flow-rate of 2 mL/min and UV detection at 235 nm. The proposed methods were successfully applied to the analysis of bumadizone either in bulk powder or in pharmaceutical formulation without interference from other dosage form additives, and the results were statistically compared with the established method.

  6. Isolation, Characterization, and RP-HPLC Estimation of P-Coumaric Acid from Methanolic Extract of Durva Grass (Cynodon dactylon Linn.) (Pers.)

    PubMed Central

    Karthikeyan, Ramadoss; Devadasu, Chapala; Srinivasa Babu, Puttagunta

    2015-01-01

    P-coumaric acid is a nonflavonoid phenolic acid and is a major constituent of the species Cynodon dactylon Linn. (Pers.). In this study isolation of P-coumaric acid was achieved by preparative TLC and the compound thus isolated was characterised by UV, mass, and H1 NMR spectral analysis. An isocratic RP-HPLC method was developed for the estimation of P-coumaric acid from methanolic extracts of durva grass. The chromatographic separations were achieved by RP-C18 column (250 mm × 4.6 mm, 5 μ), Shimadzu LC-20AT Prominence liquid chromatograph, and a mobile phase composed of water : methanol : glacial acetic acid (65 : 34 : 1 v/v). The flow rate was 1.0 mL/min and the analyses of column effluents were performed using UV-visible detector at 310 nm. Retention time of P-coumaric acid was found to be 6.617 min. This method has obeyed linearity over the concentration range of 2–10 μg/mL and the regression coefficient obtained from linearity plot for P-coumaric acid was found to be 0.999. RP-HPLC method was validated in pursuance of ICH guidelines. PMID:25788944

  7. Development and validation of RP-HPLC-UV method for simultaneous determination of buparvaquone, atenolol, propranolol, quinidine and verapamil: a tool for the standardization of rat in situ intestinal permeability studies.

    PubMed

    Venkatesh, Gantala; Ramanathan, S; Mansor, S M; Nair, N K; Sattar, Munavvar Abdul; Croft, Simon L; Navaratnam, V

    2007-03-12

    A simple, sensitive and specific reversed phase high performance liquid chromatographic (RP-HPLC) method with UV detection at 251 nm was developed for simultaneous quantitation of buparvaquone (BPQ), atenolol, propranolol, quinidine and verapamil. The method was applicable in rat in situ intestinal permeability study to assess intestinal permeability of BPQ, a promising lead compound for Leishmania donovani infections. The method was validated on a C-4 column with mobile phase comprising ammonium acetate buffer (0.02 M, pH 3.5) and acetonitrile in the ratio of 30:70 (v/v) at a flow rate of 1.0 ml/min. The retention times for atenolol, quinidine, propranolol, verapamil and BPQ were 4.30, 5.96, 6.55, 7.98 and 8.54 min, respectively. The calibration curves were linear (correlation coefficient > or =0.996) in the selected range of each analyte. The method is specific and sensitive with limit of quantitation of 15 microg/ml for atenolol, 0.8 microg/ml for quinidine, 5 microg/ml for propranolol, 10 microg/ml for verapamil and 200 ng/ml for BPQ. The validated method was found to be accurate and precise in the working calibration range. Stability studies were carried out at different storage conditions and all the analytes were found to be stable. This method is simple, reliable and can be routinely used for accurate permeability characterization.

  8. Microwave-assisted efficient extraction of different parts of Hippophae rhamnoides for the comparative evaluation of antioxidant activity and quantification of its phenolic constituents by reverse-phase high-performance liquid chromatography (RP-HPLC).

    PubMed

    Sharma, Upendra K; Sharma, Kapil; Sharma, Nandini; Sharma, Abhishek; Singh, Harsh P; Sinha, Arun K

    2008-01-23

    The outcome of different extraction procedures (microwave, ultrasound, Soxhlet, and maceration) on the antioxidant activity of seeds, leaves, pulp, and fruits of Hippophae rhamnoides (sea buckthorn or SBT) was investigated by two different bioassays: 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays. The SBT extracts were found to possess strong antioxidant activity measured in terms of TEAC (2.03-182.13 and 6.97-282.75 mg/g) with ABTS and DPPH assays, respectively. In general, the antioxidant capacity of microwave-assisted extracts was found to be significantly higher than those obtained by ultrasound-assisted extraction (UAE) and maceration while being slightly higher than Soxhlet extracts. Further, microwave extracts of seeds were found to possess maximum antioxidant capacity followed by leaves, fruits, and pulp. Also, the chemical composition of extracts, studied in terms of the total phenolic content, was found to be in the range of 1.9-23.5 mg/g Gallic acid equivalent (GAE), which indicates a strong correlation between antioxidant activity and phenolic content present in the SBT. In addition, some of its bioactive phenolic constituents, such as rutin ( 1), quercetin-3- O-galactoside ( 2), quercetin ( 3), myricetin ( 4), kaempferol ( 5), and isorhamnetin ( 6), were also quantified in different extracts by reverse-phase high-performance liquid chromatography (RP-HPLC).

  9. Purine metabolite and energy charge analysis of Trypanosoma brucei cells in different growth phases using an optimized ion-pair RP-HPLC/UV for the quantification of adenine and guanine pools.

    PubMed

    Graven, Patricia; Tambalo, Margherita; Scapozza, Leonardo; Perozzo, Remo

    2014-06-01

    Human African Trypanosomiasis (HAT) is caused by the protozoan parasite Trypanosoma brucei. Although trypanosomes are well-studied model organisms, only little is known about their adenine and guanine nucleotide pools. Besides being building blocks of RNA and DNA, these nucleotides are also important modulators of diverse biochemical cellular processes. Adenine nucleotides also play an important role in the regulation of metabolic energy. The energetic state of cells is evaluated by the energy charge which gives information about how much energy is available in form of high energy phosphate bonds of adenine nucleotides. A sensitive and reproducible ion-pair RP-HPLC/UV method was developed and optimized, allowing the quantification of guanine and adenine nucleosides/nucleotides in T. brucei. With this method, the purine levels and their respective ratios were investigated in trypanosomes during logarithmic, stationary and senescent growth phases. Results of this study showed that all adenine and guanine purines under investigation were in the low mM range. The energy charge was found to decrease from logarithmic to static and to senescent phase whereas AMP/ATP, ADP/ATP and GDP/GTP ratios increased in the same order. In addition, the AMP/ATP ratio varied as the square of the ADP/ATP ratio, indicating AMP to be the key energy sensor molecule in trypanosomes.

  10. Optimization of extraction technique and validation of developed RP-HPLC-ELSD method for determination of terpene trilactones in Ginkgo biloba leaves.

    PubMed

    Kaur, Pushpinder; Chaudhary, Abha; Singh, Bikram; Gopichand

    2009-12-05

    Terpene trilactones are potent and selective antagonists of platelet activating factor. The present study deals with standardization of efficient extraction method and validation of newly developed simple, sensitive and rapid reversed phase high performance liquid chromatographic method with evaporative light scattering detection (RP-HPLC-ELSD) method for the quantitative determination of ginkgolide A (GA), ginkgolide B (GB), ginkgolide C (GC), ginkgolide J (GJ) and bilobalide (BB) within 8 min in Ginkgo biloba leaf extract. The analysis was conducted on a Zorbax RP-C18 column with gradient elution of methanol-water-tetrahydrofuran. The method was validated for accuracy, precession, limit of detection and quantification. The drift tube temperature of evaporative light scattering detector was set to 90 degrees C and nitrogen flow rate was 1.5 standard liter/min (SLM).

  11. Tocochromanols composition in kernels recovered from different apricot varieties: RP-HPLC/FLD and RP-UPLC-ESI/MS(n) study.

    PubMed

    Górnaś, Paweł; Mišina, Inga; Grāvīte, Ilze; Soliven, Arianne; Kaufmane, Edīte; Segliņa, Dalija

    2015-01-01

    Composition of tocochromanols in kernels recovered from 16 different apricot varieties (Prunus armeniaca L.) was studied. Three tocopherol (T) homologues, namely α, γ and δ, were quantified in all tested samples by an RP-HPLC/FLD method. The γ-T was the main tocopherol homologue identified in apricot kernels and constituted approximately 93% of total detected tocopherols. The RP-UPLC-ESI/MS(n) method detected trace amounts of two tocotrienol homologues α and γ in the apricot kernels. The concentration of individual tocopherol homologues in kernels of different apricots varieties, expressed in mg/100 g dwb, was in the following range: 1.38-4.41 (α-T), 42.48-73.27 (γ-T) and 0.77-2.09 (δ-T). Moreover, the ratio between individual tocopherol homologues α:γ:δ was nearly constant in all varieties and amounted to approximately 2:39:1.

  12. Stilbenic profile of cocoa liquors from different origins determined by RP-HPLC-APCI(+)-MS/MS. Detection of a new resveratrol hexoside.

    PubMed

    Jerkovic, Vesna; Bröhan, Meike; Monnart, Elise; Nguyen, Fanny; Nizet, Sabrina; Collin, Sonia

    2010-06-09

    trans-Resveratrol and trans-piceid were recently discovered in chocolate. In the present work, both were quantified by RP-HPLC-APCI(+)-MS/MS in 22 cocoa liquors from 11 different countries. A very large range of concentrations was observed for trans-piceid. The most concentrated sample (Arriba 06) reached 0.4 and 2.6 mg/kg of trans-resveratrol and trans-piceid, respectively, but in other cultivars stilbene levels were five times lower. Neither cis-resveratrol nor cis-piceid was found in cocoa liquors. An unknown compound eluting 0.5 min before trans-piceid and present at concentrations up to 0.8 mg/kg of trans-piceid equivalents in cocoa liquors was tentatively identified by HRMS as a trans-piceid-like hexoside.

  13. Synchronous determination with double-wavelength by RP-HPLC-UV and optimization of ultrasound-assisted extraction of phenolic acids from Caragana species using response surface methodology.

    PubMed

    Zeng, Zhi; Ji, Zhongyin; Hu, Na; Chen, Shasha; Bai, Bo; Wang, Honglun; Suo, Yourui

    2017-03-14

    The utilization of Caragana korshinskii Kom. (CK) is currently concentrated on its ecological and fuel functions. Little attention has been devoted to the analysis of their phenolic acid (PA) components. To obtain more data for further utilization of CK, a new analysis protocol was tested to determine PAs synchronously by RP-HPLC-UV with double-wavelength (280nm and 320nm) detection. Specifically, separation of PA components was performed on a Hypersil Gold C18 reverse phase column with gradient elution. A four-factor-three-level Box-Behnken design was implemented for optimization of PA extraction. The results demonstrated that CK were rich primarily in chlorogenic acid, vanillic acid, caffeic acid and rosmarinic acid. The total content of PAs in CK leaves was the highest compared with its other parts. The distribution of total flavonoid content of CK was leaves>flowers>bark, while that of the total phenolic content of CK was flowers>leaves>bark.

  14. Quantitative Determination of three Angiotensin-II-receptor Antagonists in Presence of Hydrochlorothiazide by RP-HPLC in their Tablet Preparations

    PubMed Central

    Hafez, Hany Mohammed; Elshanawane, Abdullah Ahmed; Abdelaziz, Lobna Mohammed; Kamal, Magda Mohammed

    2013-01-01

    Losartan potassium, Valsartan , Telmisartan and Irbesartan are angiotensin-II-receptor antagonists (ARA II) group which used in treatment of hypertension alone or in combination with other drugs mainly Hydrochlorothiazide. RP- HPLC method was developed for the assay of three angiotensin-II-receptor antagonists (ARA-IIs) in presence of Hydrochlorothiazide. The method was performed by reversed phase high performance liquid chromatography using a mobile phase which is consisted of 0.025 M potassium dihydrogen phosphate (pH 6.0): acetonitrile = 65:35% with detection at 220 nm on an ACE C18 column (250 mm × 4.6 mm, 5 μm) at flow rate 1.5 mL/min in an isocratic manner. The proposed method was validated according to ICH guidline in terms of linearity, accuracy, precision , robustness, limit of detection and limit of quantitation. PMID:24523743

  15. Quantitative Determination of three Angiotensin-II-receptor Antagonists in Presence of Hydrochlorothiazide by RP-HPLC in their Tablet Preparations.

    PubMed

    Hafez, Hany Mohammed; Elshanawane, Abdullah Ahmed; Abdelaziz, Lobna Mohammed; Kamal, Magda Mohammed

    2013-01-01

    Losartan potassium, Valsartan , Telmisartan and Irbesartan are angiotensin-II-receptor antagonists (ARA II) group which used in treatment of hypertension alone or in combination with other drugs mainly Hydrochlorothiazide. RP- HPLC method was developed for the assay of three angiotensin-II-receptor antagonists (ARA-IIs) in presence of Hydrochlorothiazide. The method was performed by reversed phase high performance liquid chromatography using a mobile phase which is consisted of 0.025 M potassium dihydrogen phosphate (pH 6.0): acetonitrile = 65:35% with detection at 220 nm on an ACE C18 column (250 mm × 4.6 mm, 5 μm) at flow rate 1.5 mL/min in an isocratic manner. The proposed method was validated according to ICH guidline in terms of linearity, accuracy, precision , robustness, limit of detection and limit of quantitation.

  16. A novel approach for the quantitation of carbohydrates in mash, wort, and beer with RP-HPLC using 1-naphthylamine for precolumn derivatization.

    PubMed

    Rakete, Stefan; Glomb, Marcus A

    2013-04-24

    A novel universal method for the determination of reducing mono-, di-, and oligosaccharides in complex matrices on RP-HPLC using 1-naphthylamine for precolumn derivatization with sodium cyanoborhydride was established to study changes in the carbohydrate profile during beer brewing. Fluorescence and mass spectrometric detection enabled very sensitive analyses of beer-relevant carbohydrates. Mass spectrometry additionally allowed the identification of the molecular weight and thereby the degree of polymerization of unknown carbohydrates. Thus, carbohydrates with up to 16 glucose units were detected. Comparison demonstrated that the novel method was superior to fluorophore-assisted carbohydrate electrophoresis (FACE). The results proved the HPLC method clearly to be more powerful in regard to sensitivity and resolution. Analogous to FACE, this method was designated fluorophore-assisted carbohydrate HPLC (FAC-HPLC).

  17. Dual Wavelength RP-HPLC Method for Simultaneous Determination of Two Antispasmodic Drugs: An Application in Pharmaceutical and Human Serum

    PubMed Central

    Hasan, Najmul; Chaiharn, Mathurot; Khan, Sauleha; Khalid, Hira; Sher, Nawab; Siddiqui, Farhan Ahmed; Siddiqui, Muhammad Zain

    2013-01-01

    A reverse phase stability indicating HPLC method for simultaneous determination of two antispasmodic drugs in pharmaceutical parenteral dosage forms (injectable) and in serum has been developed and validated. Mobile phase ingredients consist of Acetonitrile : buffer : sulfuric acid 0.1 M (50 : 50 : 0.3 v/v/v), at flow rate 1.0 mL/min using a Hibar μBondapak ODS C18 column monitored at dual wavelength of 266 nm and 205 nm for phloroglucinol and trimethylphloroglucinol, respectively. The drugs were subjected to stress conditions of hydrolysis (oxidation, base, acid, and thermal degradation). Oxidation degraded the molecule drastically while there was not so much significant effect of other stress conditions. The calibration curve was linear with a correlation coefficient of 0.9999 and 0.9992 for PG and TMP, respectively. The drug recoveries fall in the range of 98.56% and 101.24% with 10 pg/mL and 33 pg/mL limit of detection and limit of quantification for both phloroglucinol and trimethylphloroglucinol. The method was validated in accordance with ICH guidelines and was applied successfully to quantify the amount of trimethylphloroglucinol and phloroglucinol in bulk, injectable form and physiological fluid. Forced degradation studies proved the stability indicating abilities of the method. PMID:24286017

  18. Development and Validation of a Stability-Indicating LC-Method for the Simultaneous Estimation of Levodropropizine, Chloropheniramine, Methylparaben, Propylparaben, and Levodropropizine Impurities

    PubMed Central

    Kumar, Palakurthi Ashok; Raju, Thummala Veera Raghava; Thirupathi, Dongala; Kumar, Ravindra; Shree, Jaya

    2013-01-01

    A simple, fast, and efficient RP-HPLC method has been developed and validated for the simultaneous estimation of Levodropropizine, Chloropheniramine, Methylparaben, Propylparaben, and the quantification of Levodropropizine impurities in the Reswas syrup dosage form. A gradient elution method was used for the separation of all the actives and Levodropropizine impurities by using the X-Bridge C18, 150 mm × 4.6 mm, 3.5 μm column with a flow rate of 1.0 mL/min and detector wavelength at 223 nm. The mobile phase consisted of a potassium dihydrogen orthophosphate buffer and acetonitrile. All the peaks were symmetrical and well-resolved (resolution was greater than 2.5 for any pair of components) with a shorter run time. The limit of detection for Levodropropizine and its Impurity B was 0.07 μg/ml & 0.05 μg/ml, whereas the limit of quantification was 0.19 μg/ml & 0.15 μg/ml respectively. The method was validated in terms of precision, accuracy, linearity, robustness, and specificity. Degradation products resulting from the stress studies were well-resolved and did not interfere with the detection of Levodropropizine, Chloropheniramine, Methylparaben, Propylparaben, and Levodropropizine Impurity B, thus the test method is stability-indicating. Validation of the method was carried out as per International Conference on Harmonization (ICH) guidelines. PMID:23641334

  19. Development and validation of a stability-indicating RP-HPL C-CAD method for gabapentin and its related impurities in presence of degradation products.

    PubMed

    Ragham, Pramod Kumar; Chandrasekhar, Kothapalli B

    2016-06-05

    The objective of the current study was to develop and validate a sensitive and specific LC-MS compatible stability indicating reversed phase liquid chromatographic method for the quantitative determination of Gabapentin and its related substances using Corona charged aerosol detection (CAD). The chromatographic conditions were optimized using a Kinetix Biphenyl column with gradient elution using a mobile phase composed of pH 4.2 ammonium acetate, acetonitrile, and methanol. Forced degradation was observed in basic and peroxide conditions and the major degradants were identified by LC-MS/MS analysis. The developed RP-HPLC CAD method was validated according to ICH guidelines. The LOD and LOQ values for Gabapentin and all its related impurities ranged from 0.075μg/mL to 0.18μg/mL and 0.25μg/mL to 0.60μg/mL, respectively. The recovery for all impurities ranged from 91.0 to 105.6%w/w. Solutions were stable for 7days at room temperature. The validated method produced acceptable precision, linearity, accuracy, robustness and ruggedness.

  20. Development and Validation of a Stability-Indicating LC-Method for the Simultaneous Estimation of Levodropropizine, Chloropheniramine, Methylparaben, Propylparaben, and Levodropropizine Impurities.

    PubMed

    Kumar, Palakurthi Ashok; Raju, Thummala Veera Raghava; Thirupathi, Dongala; Kumar, Ravindra; Shree, Jaya

    2013-01-01

    A simple, fast, and efficient RP-HPLC method has been developed and validated for the simultaneous estimation of Levodropropizine, Chloropheniramine, Methylparaben, Propylparaben, and the quantification of Levodropropizine impurities in the Reswas syrup dosage form. A gradient elution method was used for the separation of all the actives and Levodropropizine impurities by using the X-Bridge C18, 150 mm × 4.6 mm, 3.5 μm column with a flow rate of 1.0 mL/min and detector wavelength at 223 nm. The mobile phase consisted of a potassium dihydrogen orthophosphate buffer and acetonitrile. All the peaks were symmetrical and well-resolved (resolution was greater than 2.5 for any pair of components) with a shorter run time. The limit of detection for Levodropropizine and its Impurity B was 0.07 μg/ml & 0.05 μg/ml, whereas the limit of quantification was 0.19 μg/ml & 0.15 μg/ml respectively. The method was validated in terms of precision, accuracy, linearity, robustness, and specificity. Degradation products resulting from the stress studies were well-resolved and did not interfere with the detection of Levodropropizine, Chloropheniramine, Methylparaben, Propylparaben, and Levodropropizine Impurity B, thus the test method is stability-indicating. Validation of the method was carried out as per International Conference on Harmonization (ICH) guidelines.

  1. Antioxidant, Biomolecule Oxidation Protective Activities of Nardostachys jatamansi DC and Its Phytochemical Analysis by RP-HPLC and GC-MS

    PubMed Central

    Razack, Sakina; Hemanth Kumar, Kandikattu; Nallamuthu, Ilaiyaraja; Naika, Mahadeva; Khanum, Farhath

    2015-01-01

    The study aimed at analyzing the metabolite profile of Nardostachys jatamansi using RP-HPLC, GC-MS and also its antioxidant, biomolecule protective and cytoprotective properties. The 70% ethanolic extract of Nardostachys jatamansi (NJE) showed the presence of polyphenols and flavonoids (gallic acid, catechin, chlorogenic acid, homovanillin, epicatechin, rutin hydrate and quercetin-3-rhamnoside) analyzed by RP-HPLC, whereas hexane extract revealed an array of metabolites (fatty acids, sesquiterpenes, alkane hydrocarbons and esters) by GC-MS analysis. The antioxidant assays showed the enhanced potency of NJE with a half maximal inhibitory concentration (IC50) value of 222.22 ± 7.4 μg/mL for 2,2-diphenyl-1-picrylhydrazyl (DPPH), 13.90 ± 0.5 μg/mL for 2,2′-azino-bis(3-ethyl benzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 113.81 ± 4.2 μg/mL for superoxide, 948 ± 21.1 μg/mL for metal chelating and 12.3 ± 0.43 mg FeSO4 equivalent/g of extract for ferric reducing antioxidant power assays and was more potent than hexane extract. NJE effectively inhibited 2,2′-azobis(2-methylpropionamidine) dihydrochloride (AAPH)-induced oxidation of biomolecules analyzed by pBR322 plasmid DNA damage, protein oxidation of bovine serum albumin and lipid peroxidation assays. The observed effects might be due to the high content of polyphenols, 53.06 ± 2.2 mg gallic acid equivalents/g, and flavonoids, 25.303 ± 0.9 mg catechin equivalents/g, of NJE compared to the hexane fraction. Additionally, the extract abrogated the protein, carbonyl, and ROS formation, and NJE showed cytotoxicity in SH-SY5Y neuronal cells above 75 μg/mL. Thus, the study suggests that the herb unequivocally is a potential source of antioxidants and could aid in alleviating oxidative stress-mediated disorders. PMID:26785345

  2. [Simultaneous separation and detection of principal component isomer and related substances of raw material drug of ammonium glycyrrhizinate by RP-HPLC and structure confirmation].

    PubMed

    Zhao, Yan-Yan; Liu, Li-Yan; Han, Yuan-Yuan; Li, Yue-Qiu; Wang, Yan; Shi, Min-Jian

    2013-08-01

    A simple, fast and sensitive analytical method for the simultaneous separation and detection of 18alpha-glycyrrhizinic acid, 18beta-glycyrrhizinic acid, related substance A and related substance B by RP-HPLC and drug quality standard was established. The structures of principal component isomer and related substances of raw material drug of ammonium glycyrrhizinate have been confirmed. Reference European Pharmacopoeia EP7.0 version, British Pharmacopoeia 2012 version, National Drug Standards of China (WS 1-XG-2002), domestic and international interrelated literature were referred to select the composition of mobile phase. The experimental parameters including salt concentration, pH, addition quantities of organic solvent, column temperature and flow rate were optimized. Finally, the assay was conducted on a Durashell-C18 column (250 mm x 4.6 mm, 5 microm) with 0.01 mol x mL(-1) ammonium perchlorate (add ammonia to adjust the pH value to 8.2) -methanol (48 : 52) as mobile phase at the flow rate of 0.8 mL x min(-1), and the detection wavelength was set at 254 nm. The column temperature was 50 degrees C and the injection volume was 10 microL. The MS, NMR, UV and RP-HPLC were used to confirm the structures of principal component isomer and related substances of raw material drug of ammonium glycyrrhizinate. Under the optimized separation conditions, the calibration curves of 18 alpha-glycyrrhizinic acid, 18beta-glycyrrhizinic acid, related substance A and related substance B showed good linearity within the concentration of 0.50-100 microg x mL(-1) (r = 0.999 9). The detection limits for 18alpha-glycyrrhizinic acid, 18beta-glycyrrhizinic acid, related substance A and related substance B were 0.15, 0.10, 0.10, 0.15 microg x mL(-1) respectively. The method is sensitive, reproducible and the results are accurate and reliable. It can be used for chiral resolution of 18alpha-glycyrrhizinic acid, 18Pbeta-glycyrrhizinic acid, and detection content of principal component and

  3. Antioxidant, Biomolecule Oxidation Protective Activities of Nardostachys jatamansi DC and Its Phytochemical Analysis by RP-HPLC and GC-MS.

    PubMed

    Razack, Sakina; Kumar, Kandikattu Hemanth; Nallamuthu, Ilaiyaraja; Naika, Mahadeva; Khanum, Farhath

    2015-03-12

    The study aimed at analyzing the metabolite profile of Nardostachys jatamansi using RP-HPLC, GC-MS and also its antioxidant, biomolecule protective and cytoprotective properties. The 70% ethanolic extract of Nardostachys jatamansi (NJE) showed the presence of polyphenols and flavonoids (gallic acid, catechin, chlorogenic acid, homovanillin, epicatechin, rutin hydrate and quercetin-3-rhamnoside) analyzed by RP-HPLC, whereas hexane extract revealed an array of metabolites (fatty acids, sesquiterpenes, alkane hydrocarbons and esters) by GC-MS analysis. The antioxidant assays showed the enhanced potency of NJE with a half maximal inhibitory concentration (IC50) value of 222.22 ± 7.4 μg/mL for 2,2-diphenyl-1-picrylhydrazyl (DPPH), 13.90 ± 0.5 μg/mL for 2,2'-azino-bis(3-ethyl benzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 113.81 ± 4.2 μg/mL for superoxide, 948 ± 21.1 μg/mL for metal chelating and 12.3 ± 0.43 mg FeSO₄ equivalent/g of extract for ferric reducing antioxidant power assays and was more potent than hexane extract. NJE effectively inhibited 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH)-induced oxidation of biomolecules analyzed by pBR322 plasmid DNA damage, protein oxidation of bovine serum albumin and lipid peroxidation assays. The observed effects might be due to the high content of polyphenols, 53.06 ± 2.2 mg gallic acid equivalents/g, and flavonoids, 25.303 ± 0.9 mg catechin equivalents/g, of NJE compared to the hexane fraction. Additionally, the extract abrogated the protein, carbonyl, and ROS formation, and NJE showed cytotoxicity in SH-SY5Y neuronal cells above 75 μg/mL. Thus, the study suggests that the herb unequivocally is a potential source of antioxidants and could aid in alleviating oxidative stress-mediated disorders.

  4. Simultaneous RP-HPLC-DAD quantification of bromocriptine, haloperidol and its diazepane structural analog in rat plasma with droperidol as internal standard for application to drug-interaction pharmacokinetics

    PubMed Central

    Billups, Johnique; Jones, Cynthia; Jackson, Tanise L.; Ablordeppey, Seth Y.; Spencer, Shawn D.

    2010-01-01

    A simple and rapid RP-HPLC-DAD method was developed and validated for simultaneous determination of the dopamine antagonists haloperidol, its diazepane analog, and the dopamine agonist bromocriptine in rat plasma, to perform pharmacokinetic drug-interaction studies. Samples were prepared for analysis by acetonitrile (22.0 μg/mL) plasma protein precipitation with droperidol as an internal standard, followed by a double-step liquid-liquid extraction with hexane:chloroform (70:30) prior to C-18 separation. Isocratic elution was achieved using a 0.1% (v/v) trifluoroacetic acid in deionized water, methanol and acetonitrile (45/27.5/27.5, v/v/v). Triple-wavelength diode-array detection at the λmax of 245 nm for haloperidol, 254 nm for the diazepane analog and droperidol, and 240 nm for bromocriptine was carried out. The LLOQ of DAL, HAL, and BCT were 45.0, 56.1, and 150 ng/mL, respectively. In rats, the estimated pharmacokinetic parameters (i.e., t1/2, CL, and Vss) of HAL when administered with DAL and BCT were t1/2 = 16.4 min, Vss = 0.541 L/kg for HAL, t1/2 = 28.0 min, Vss = 2.00 L/kg for DAL, and t1/2 = 24.0 min, Vss = 0.106 L/kg for BCT. The PK parameters for HAL differed significantly from those previously reported, which may be an indication of a drug-drug interaction. PMID:19908205

  5. Separation and quantitative determination of cinacalcet metabolites in urine sample using RP-HPLC after derivation with a fluorescent labeling reagent.

    PubMed

    Farnoudian-Habibi, Amir; Jaymand, Mehdi

    2016-08-01

    In this investigation, a novel strategy for separation and quantitative determination of four metabolites of cinacalcet (M2a-Glu, M2b-Glu, M7-Gly, and M8-Gly) in human urine is suggested. The analytical assay is based on a pre-column derivation procedure of cinacalcet metabolites with 1-pyrenyldiazomethane (PDAM) as a fluorescent labeling reagent, and subsequently separation and quantitative determination with reverse-phase high-performance liquid chromatography (RP-HPLC) coupled with a fluorescence detector. Metabolites were separated on a Microsorb-MV 100-5 C18 chromatography column (250×4.6mm, 5μm) using acetate buffer (pH 3.5):methanol (30:70 v/v) as mobile phase at a flow rate of 1.0mLmin(-1). The method was fully validated in terms of linearity (r(2)>0.996; 1-10ngmL(-1)), precision (both intra-day and inter-day; RSD<6.2%), accuracy (92-110%), specificity, robustness (0.15%

  6. The salivary proteome profile in patients affected by SAPHO syndrome characterized by a top-down RP-HPLC-ESI-MS platform.

    PubMed

    Sanna, Monica; Firinu, Davide; Manconi, Paolo Emilio; Pisanu, Maria; Murgia, Giuseppe; Piras, Valentina; Castagnola, Massimo; Messana, Irene; del Giacco, Stefano Renato; Cabras, Tiziana

    2015-06-01

    SAPHO syndrome is a rare and often unrecognized disease with prominent inflammatory cutaneous and articular symptoms characterized by musculoskeletal manifestations (synovitis, hyperostosis, osteomyelitis) associated with dermatological conditions (severe acne and pustulosis). The acidic soluble fraction of whole saliva from 10 adult women affected by SAPHO syndrome and from a group of 28 healthy women was analysed by RP-HPLC-ESI-MS with the aim of discovering salivary biomarkers of the disorder. The levels of the oral proteins and peptides were correlated with clinical data. The following proteins showed a significant decreased concentration in saliva of SAPHO subjects with respect to controls: cystatin S1 and SN, histatins, the major acidic PRPs, P-C and P-B peptides. The cystatin SN abundance lowered according to the disease duration and histatins showed positive correlations with the C reactive protein. Statistical analysis performed excluding one patient with a different pattern of salivary proteins/peptides highlighted a positive relationship between cystatin S1, histatins 3, histatin 5, and the neutrophil count. Moreover, histatin 3 correlated positively with the total white cell count and negatively with the erythrocyte sedimentation rate. Levels and frequency of S100A12 protein showed a trend to increase in SAPHO patients. The high expression of this pro-inflammatory protein is probably related to the inflammatory response and to the altered neutrophil responses to functional stimuli that characterize SAPHO syndrome suggesting a possible application as a salivary biomarker.

  7. Evaluation of a Propolis Water Extract Using a Reliable RP-HPLC Methodology and In Vitro and In Vivo Efficacy and Safety Characterisation.

    PubMed

    Rocha, Bruno Alves; Bueno, Paula Carolina Pires; Vaz, Mirela Mara de Oliveira Lima Leite; Nascimento, Andresa Piacezzi; Ferreira, Nathália Ursoli; Moreno, Gabriela de Padua; Rodrigues, Marina Rezende; Costa-Machado, Ana Rita de Mello; Barizon, Edna Aparecida; Campos, Jacqueline Costa Lima; de Oliveira, Pollyanna Francielli; Acésio, Nathália de Oliveira; Martins, Sabrina de Paula Lima; Tavares, Denise Crispim; Berretta, Andresa Aparecida

    2013-01-01

    Since the beginning of propolis research, several groups have studied its antibacterial, antifungal, and antiviral properties. However, most of these studies have only employed propolis ethanolic extract (PEE) leading to little knowledge about the biological activities of propolis water extract (PWE). Based on this, in a previous study, we demonstrated the anti-inflammatory and immunomodulatory activities of PWE. In order to better understand the equilibrium between effectiveness and toxicity, which is essential for a new medicine, the characteristics of PWE were analyzed. We developed and validated an RP-HPLC method to chemically characterize PWE and PEE and evaluated the in vitro antioxidant/antimicrobial activity for both extracts and the safety of PWE via determining genotoxic potential using in vitro and in vivo mammalian micronucleus assays. We have concluded that the proposed analytical methodology was reliable, and both extracts showed similar chemical composition. The extracts presented antioxidant and antimicrobial effects, while PWE demonstrated higher antioxidant activity and more efficacious for the most of the microorganisms tested than PEE. Finally, PWE was shown to be safe using micronucleus assays.

  8. Determination of free and bound phenolic compounds in buckwheat spaghetti by RP-HPLC-ESI-TOF-MS: effect of thermal processing from farm to fork.

    PubMed

    Verardo, Vito; Arraez-Roman, David; Segura-Carretero, Antonio; Marconi, Emanuele; Fernandez-Gutierrez, Alberto; Caboni, Maria Fiorenza

    2011-07-27

    Nowadays there is considerable interest in the consumption of alternative crops as potential recipes for gluten-free products production. Therefore, the use of buckwheat for the production of gluten-free pasta has been investigated in the present study. RP-HPLC-ESI-TOF-MS has been applied for the separation and characterization of free and bound phenolic compounds in buckwheat flour and buckwheat spaghetti. Thus, 32 free and 24 bound phenolic compounds in buckwheat flour and spaghetti have been characterized and quantified. To the authors' knowledge, protochatechuic-4-O-glucoside acid and procyanidin A have been detected in buckwheat for the first time. The results have demonstrated a decrease of total free phenolic compounds from farm to fork (from flour to cooked spaghetti) of about 74.5%, with a range between 55.3 and 100%, for individual compounds. The decrease in bound phenols was 80.9%, with a range between 46.2 and 100%. The spaghetti-making process and the cooking caused losses of 46.1 and 49.4% of total phenolic compounds, respectively. Of the total phenolic compounds present in dried spaghetti, 11.6% were dissolved in water after cooking.

  9. Simultaneous determination of 15 phenolic compounds and caffeine in teas and mate using RP-HPLC/UV detection: method development and optimization of extraction process.

    PubMed

    Bae, In Kyung; Ham, Hyeon Mi; Jeong, Min Hee; Kim, Dong Ho; Kim, Ho Jin

    2015-04-01

    A reversed-phase high performance liquid chromatographic coupled to ultraviolet detection (RP-HPLC/UV) method was developed for simultaneous determination of 15 phenolic compounds and caffeine in TEAS (green tea, oolong tea, black tea and mate). Furthermore, the extraction process of total phenolic contents (TPC) from TEAS were optimized using response surface methodology (RSM) based on a central composite design (CCD) and then applied to extraction of TEAS. The best conditions obtained using the model were as follow: green tea--extraction time of 123 min, extraction temperature of 70 °C and ethanol concentration of 75%, oolong tea--extraction time of 98 min, extraction temperature of 70 °C and ethanol concentration of 69%, black tea--extraction time of 105 min, extraction temperature of 71 °C and ethanol concentration of 63%, and mate--extraction time of 103 min, extraction temperature of 71 °C and ethanol concentration of 61%. Among the extraction methods used in this study, heat-reflux extraction was found to result in the highest values of TPC. The chromatographic peaks of the 16 studied compounds were successfully identified by comparing their retention time and UV spectra with the reference standards. Method validation was performed by means of linearity, sensitivity, selectivity, accuracy and precision. The developed method was found to be simple, specific and reliable and is suited for routine analysis of phenolic compounds and caffeine in TEAS.

  10. Ionic liquid-based dispersive liquid-liquid microextraction followed by RP-HPLC determination of saquinavir in rat serum: application to pharmacokinetics.

    PubMed

    Ramisetti, Nageswara Rao; Nimmu, Narendra Varma; Challa, Gangu Naidu

    2014-12-01

    An ionic liquid-based dispersive liquid-liquid microextraction followed by RP-HPLC determination of the most commonly prescribed protease inhibitor, saquinavir, in rat plasma was developed and validated. The effects of different ionic liquids, dispersive solvents, extractant/disperser ratio and salt concentration on sample recovery and enrichment were studied. Among the ionic liquids investigated, 1-butyl-3-methylimidazolium hexafluorophosphate was found to be most effective for extraction of saquinavir from rat serum. The recovery was found to be 95% at an extractant/disperser ratio of 0.43 using 1-butyl-3-methylimidazolium hexafluorophosphate and methanol as extraction and dispersive solvents. The recovery was further enhanced to 99.5% by addition of 5.0% NaCl. A threefold enhancement in detection and quantification limits was achieved, at 0.01 and 0.03 µg/mL, compared with the conventional protein precipitation method. A linear relationship was observed in the range of 0.035-10.0 µg/mL with a correlation coefficient (r(2) ) of 0.9996. The method was validated and applied to study pharmacokinetics of saquinavir in rat serum.

  11. Mapping of Complete Set of Ribose and Base Modifications of Yeast rRNA by RP-HPLC and Mung Bean Nuclease Assay

    PubMed Central

    Watzinger, Peter; Hartmann, Johannes David; Kötter, Peter; Entian, Karl-Dieter

    2016-01-01

    Ribosomes are large ribonucleoprotein complexes that are fundamental for protein synthesis. Ribosomes are ribozymes because their catalytic functions such as peptidyl transferase and peptidyl-tRNA hydrolysis depend on the rRNA. rRNA is a heterogeneous biopolymer comprising of at least 112 chemically modified residues that are believed to expand its topological potential. In the present study, we established a comprehensive modification profile of Saccharomyces cerevisiae’s 18S and 25S rRNA using a high resolution Reversed-Phase High Performance Liquid Chromatography (RP-HPLC). A combination of mung bean nuclease assay, rDNA point mutants and snoRNA deletions allowed us to systematically map all ribose and base modifications on both rRNAs to a single nucleotide resolution. We also calculated approximate molar levels for each modification using their UV (254nm) molar response factors, showing sub-stoichiometric amount of modifications at certain residues. The chemical nature, their precise location and identification of partial modification will facilitate understanding the precise role of these chemical modifications, and provide further evidence for ribosome heterogeneity in eukaryotes. PMID:28033325

  12. Method development and validation for simultaneous determination of lumefantrine and its major metabolite, desbutyl lumefantrine in human plasma using RP-HPLC/UV detection.

    PubMed

    Khuda, Fazli; Iqbal, Zafar; Shah, Yasar; Ahmmad, Lateef; Nasir, Fazli; Khan, Amir Zada; Amanullah; Shahbaz, Naila

    2014-01-01

    A simple, specific, precise and rapid RP-HPLC-UV method was developed for simultaneous determination of lumefantrine and its metabolite desbutyl lumefantrine in human plasma. Experimental parameters were optimized and the method was validated according to standard guidelines. The method showed adequate separation for lumefantrine and desbutyl lumefantrine and best resolution was achieved with Supelco Discovery HS C18 RP (150mm×4.6mm, 5μm) column using acetonitrile and 0.05% trifluroacetic acid (70:30, v/v) as a mobile phase pumped at a flow rate of 1.0ml/min and wavelength of 335nm. The method was linear over the concentration range of 10-12,000ng/ml. The lower limit of detection (LLOD) and lower limit of quantification (LLOQ) for lumefantrine were 10.0 and 18.0ng/ml, while for desbutyl lumefantrine were 7.5 and 15.0ng/ml, respectively. The proposed method was efficiently applied for determination of lumefantrine and desbutyl lumefantrine concentrations in plasma samples for pharmacokinetic studies.

  13. Effects of ionic liquid as additive and the pH of the mobile phase on the retention factors of amino benzoic acids in RP-HPLC.

    PubMed

    Zheng, J; Polyakova, Y; Row, K H

    2007-01-01

    As an organic salt, ionic liquids are widely used as new solvent media. In this paper, three positional isomers, such as o-amino benzoic acid, m-amino benzoic acid, and p-amino benzoic acid are separated with four different ionic liquids as additives to the mobile phase using reversed-phase (RP) high-performance liquid chromatography (HPLC). Amino benzoic acids are biologically active substances; the p-isomer is present in a group of water-soluble vitamins and is widely known as a sunscreen agent. The ionic liquids used are 1-butyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium methylsulfate, and 1-octyl-3-methylimidazolium methylsulfate. The effects of the length of the alkyl group on the imidazolium ring and its counterion, the concentrations of the ionic liquid, and the effect of the pH of the mobile phase on the retention factor of the amino benzoic acid isomers are studied. Separation with the ionic liquid in the eluent was better than the separation without the ionic liquid. The pH mainly affected the retention and elution order of the solutes in RP-HPLC.

  14. Simultaneous determination of pyridoxine hydrochloride and doxylamine succinate from tablets by ion pair reversed-phase high-performance liquid chromatography (RP-HPLC).

    PubMed

    Argekar, A P; Sawant, J G

    1999-08-01

    A new, simple, precise, and rapid ion pair reversed-phase high-performance liquid chromatography (RP-HPLC) method has been developed for the simultaneous determination of pyridoxine hydrochloride (PYR) and doxylamine succinate (DOX) in tablets. The stationary phase was a Microbondapak C18 column (10 mu, 300 mm x 3.9 mm i.d.). The mobile phase was water:methanol (60:40) containing 10 mM heptanesulfonic acid and 0.25% triethylamine and adjusted to pH 2.2 with orthophosphoric acid. Detection was carried out at 263 nm using an ultraviolet (UV) detector. The flow rate was 1.0 ml/min, and retention times were 3.65 min and 7.32 min for PYR and DOX, respectively. The linearity was obtained in the concentration range 0.5-500 micrograms/ml for PYR and DOX. Mean percentage recoveries were 100.20% and 101.20% for PYR and DOX, respectively.

  15. Identification and optimization of parameters for the semi-continuous production of garbage enzyme from pre-consumer organic waste by green RP-HPLC method.

    PubMed

    Arun, C; Sivashanmugam, P

    2015-10-01

    Reuse and management of organic solid waste, reduce the environmental impact on human health and increase the economic status by generating valuable products for current and novel applications. Garbage enzyme is one such product produced from fermentation of organic solid waste and it can be used as liquid fertilizer, antimicrobial agents, treatment of domestic wastewater, municipal and industrial sludge treatment, etc. The semi-continuous production of garbage enzyme in large quantity at minimal time period and at lesser cost is needed to cater for treatment of increasing quantities of industrial waste activated sludge. This necessitates a parameter for monitoring and control for the scaling up of current process on semi-continuous basis. In the present study a RP-HPLC (Reversed Phase-High Performance Liquid Chromatography) method is used for quantification of standard organic acid at optimized condition 30°C column oven temperature, pH 2.7, and 0.7 ml/min flow rate of the mobile phase (potassium dihydrogen phosphate in water) at 50mM concentration. The garbage enzyme solution collected in 15, 30, 45, 60, 75 and 90 days were used as sample to determine the concentration of organic acid. Among these, 90th day sample showed the maximum concentration of 78.14 g/l of acetic acid in garbage enzyme, whereas other organic acids concentration got decreased when compare to the 15th day sample. This result confirms that the matured garbage enzyme contains a higher concentration of acetic acid and thus it can be used as a monitoring parameter for semi-continuous production of garbage enzyme in large scale.

  16. A simple, rapid and sensitive RP-HPLC-UV method for the simultaneous determination of sorafenib & paclitaxel in plasma and pharmaceutical dosage forms: Application to pharmacokinetic study.

    PubMed

    Khan, Ismail; Iqbal, Zafar; Khan, Abad; Hassan, Muhammad; Nasir, Fazle; Raza, Abida; Ahmad, Lateef; Khan, Amjad; Akhlaq Mughal, Muhammad

    2016-10-15

    A simple, economical, fast, and sensitive RP-HPLC-UV method has been developed for the simultaneous quantification of Sorafenib and paclitaxel in biological samples and formulations using piroxicam as an internal standard. The experimental conditions were optimized and method was validated according to the standard guidelines. The separation of both the analytes and internal standard was achieved on Discovery HS C18 column (250mm×4.6mm, 5μm) using Acetonitrile and TFA (0.025%) in the ratio of (65:35V/V) as the mobile phase in isocratic mode at a flow rate of 1ml/min, with a wavelength of 245nm and at a column oven temperature of 25°Cin a short run time of 12min. The limits of detection (LLOD) were 5 and 10ng/ml while the limits of quantification (LLOQ) were 10 and 15ng/ml for sorafenib and paclitaxel, respectively. Sorafenib, paclitaxel and piroxicam (IS) were extracted from biological samples by applying acetonitrile as a precipitating and extraction solvent. The method is linear in the range of 15-20,000ng/ml for paclitaxel and 10-5000ng/ml for sorafenib, respectively. The method is sensitive and reliable by considering both of its intra-day and inter-day co-efficient of variance. The method was successfully applied for the quantification of the above mentioned drugs in plasma. The developed method will be applied towards sorafenib and paclitaxel pharmacokinetics studies in animal models.

  17. Chemometrics-Assisted UV Spectrophotometric and RP-HPLC Methods for the Simultaneous Determination of Tolperisone Hydrochloride and Diclofenac Sodium in their Combined Pharmaceutical Formulation

    PubMed Central

    Gohel, Nikunj Rameshbhai; Patel, Bhavin Kiritbhai; Parmar, Vijaykumar Kunvarji

    2013-01-01

    Chemometrics-assisted UV spectrophotometric and RP-HPLC methods are presented for the simultaneous determination of tolperisone hydrochloride (TOL) and diclofenac sodium (DIC) from their combined pharmaceutical dosage form. Chemometric methods are based on principal component regression and partial least-square regression models. Two sets of standard mixtures, calibration sets, and validation sets were prepared. Both models were optimized to quantify each drug in the mixture using the information included in the UV absorption spectra of the appropriate solution in the range 241–290 nm with the intervals λ = 1 nm at 50 wavelengths. The optimized models were successfully applied to the simultaneous determination of these drugs in synthetic mixture and pharmaceutical formulation. In addition, an HPLC method was developed using a reversed-phase C18 column at ambient temperature with a mobile phase consisting of methanol:acetonitrile:water (60:30:10 v/v/v), pH-adjusted to 3.0, with UV detection at 275 nm. The methods were validated in terms of linearity, accuracy, precision, sensitivity, specificity, and robustness in the range of 3–30 μg/mL for TOL and 1–10 μg/mL for DIC. The robustness of the HPLC method was tested using an experimental design approach. The developed HPLC method, and the PCR and PLS models were used to determine the amount of TOL and DIC in tablets. The data obtained from the PCR and PLS models were not significantly different from those obtained from the HPLC method at 95% confidence limit. PMID:24482768

  18. Chemometrics-Assisted UV Spectrophotometric and RP-HPLC Methods for the Simultaneous Determination of Tolperisone Hydrochloride and Diclofenac Sodium in their Combined Pharmaceutical Formulation.

    PubMed

    Gohel, Nikunj Rameshbhai; Patel, Bhavin Kiritbhai; Parmar, Vijaykumar Kunvarji

    2013-01-01

    Chemometrics-assisted UV spectrophotometric and RP-HPLC methods are presented for the simultaneous determination of tolperisone hydrochloride (TOL) and diclofenac sodium (DIC) from their combined pharmaceutical dosage form. Chemometric methods are based on principal component regression and partial least-square regression models. Two sets of standard mixtures, calibration sets, and validation sets were prepared. Both models were optimized to quantify each drug in the mixture using the information included in the UV absorption spectra of the appropriate solution in the range 241-290 nm with the intervals λ = 1 nm at 50 wavelengths. The optimized models were successfully applied to the simultaneous determination of these drugs in synthetic mixture and pharmaceutical formulation. In addition, an HPLC method was developed using a reversed-phase C18 column at ambient temperature with a mobile phase consisting of methanol:acetonitrile:water (60:30:10 v/v/v), pH-adjusted to 3.0, with UV detection at 275 nm. The methods were validated in terms of linearity, accuracy, precision, sensitivity, specificity, and robustness in the range of 3-30 μg/mL for TOL and 1-10 μg/mL for DIC. The robustness of the HPLC method was tested using an experimental design approach. The developed HPLC method, and the PCR and PLS models were used to determine the amount of TOL and DIC in tablets. The data obtained from the PCR and PLS models were not significantly different from those obtained from the HPLC method at 95% confidence limit.

  19. Simultaneous determination of L-arginine and 12 molecules participating in its metabolic cycle by gradient RP-HPLC method: application to human urine samples.

    PubMed

    Markowski, Piotr; Baranowska, Irena; Baranowski, Jacek

    2007-12-19

    We have developed and described a highly sensitive, accurate and precise reversed-phase high-performance liquid chromatography (RP-HPLC) method for the simultaneous determination of L-arginine and 12 molecules participating in its metabolic cycle in human urine samples. After pre-column derivatization with ortho-phthaldialdehyde (OPA) reagent containing 3-mercaptopropionic acid (3MPA), the fluorescent derivatives were separated by a gradient elution and detected by fluorescence measurement at 338 nm (excitation) and 455 nm (emission). L-Arginine (ARG) and its metabolites: L-glutamine (GLN), N(G)-hydroxy-L-arginine (NOHA), L-citrulline (CIT), N(G)-monomethyl-L-arginine (NMMA), L-homoarginine (HARG), asymmetric N(G),N(G)-dimethyl-L-arginine (ADMA), symmetric N(G),N(G')-dimethyl-L-arginine (SDMA), L-ornithine (ORN), putrescine (PUT), agmatine (AGM), spermidine (SPERMD) and spermine (SPERM) were extracted in a cation-exchange solid-phase extraction (SPE) column and after derivatization separated in a Purospher STAR RP-18e analytical column. The calibration curves of analysed compounds are linear within the range of concentration: 45-825, 0.2-15, 16-225, 12-285, 0.1-32, 15-235, 0.1-12, 0.1-12, 10-205, 0.02-12, 0.1-24, 0.01-10 and 0.01-8 nmol mL(-1) for GLN, NOHA, CIT, ARG, NMMA, HARG, ADMA, SDMA, ORN, PUT, AGM, SPERMD and SPERM, respectively. The correlation coefficients are greater than 0.9980. Coefficients of variation are not higher than 6.0% for inter-day precision. The method has been determined or tested for limits of detection and quantification, linearity, precision, accuracy and recovery. All detection parameters of the method demonstrate that it is a reliable and efficient means of the comprehensive determination of ARG and its 12 main metabolites, making this approach suitable for routine clinical applications. The levels of analysed compounds in human urine can be successfully determined using this developed method with no matrix effect.

  20. Validation of RP-HPLC method and stress degradation for the combination of metformin HCl, atorvastatin calcium and glimepiride: application to nanoparticles.

    PubMed

    Gite, Sandip; Patravale, Vandana

    2015-01-01

    A stability-indicating high-performance liquid chromatography (HPLC) procedure was developed for the determination of metformin HCl (MTH), atorvastatin calcium (AC) and glimepiride (GP) in combination and their main degradation products. The separation and quantization were achieved on a 5-µm Qualisil gold, C18 column (4.6 mm × 250 mm). The mobile phase selected was phosphate buffer (pH 2.9)-organic phase in proportion of 70:30. Organic phase consisted of methanol-acetonitrile (90:10) at a flow rate of 1 mL/min and detection of analytes was carried out at 230 nm. The method exhibited good linearity over the range of 10-60 µg/mL for MTH, 2-20 µg/mL for AC and 5-30 µg/mL for GP. Square of the correlation coefficients was found to be >0.999. Various stress degradation studies were carried out in combination as per International Conference of Harmonization (ICH) guidelines for 4 h. The recovery and precision were determined in terms of intraday and interday precisions and expressed as relative standard deviations. These were <1 and <2%, respectively. Finally, the applicability of the method was evaluated in nanoparticle analysis of MTH, AC and GP as well as in stability studies of nanoformulation.

  1. Development and validation of a novel stability-indicating HPLC method for the quantitative determination of eleven related substances in ezetimibe drug substance and drug product.

    PubMed

    Luo, Zhiqiang; Deng, Zhongqing; Liu, Yang; Wang, Guopeng; Yang, Wenning; Hou, Chengbo; Tang, Minming; Yang, Ruirui; Zhou, Huaming

    2015-07-01

    Ezetimibe is a novel lipid-lowering agent that inhibits intestinal absorption of dietary and biliary cholesterol. In the present work, a simple, sensitive and reproducible gradient reverse phase high performance liquid chromatographic (RP-HPLC) method for separation and determination of the related substances of ezetimibe was developed and validated. Eleven potential process-related impurities (starting materials, (3S,4S,3'S)-isomer, degradants and byproducts) were identified in the crude samples. Tentative structures for all the impurities were assigned primarily based on comparison of their retention time and mass spectrometric data with that of available standards and references. This method can be applied to routine analysis in quality control of both bulk drugs and commercial tablets. Separation of all these compounds was performed on a Phenomenex Luna Phenyl-Hexyl (100mm×4.6mm, 5μm) analytical column. The mobile phase-A consists of acetonitrile-water (pH adjusted to 4.0 with phosphoric acid)-methanol at 15:75:10 (v/v/v), and mobile phase-B contains acetonitrile. The eluted compounds were monitored at 210nm. Ezetimibe was subjected to hydrolytic, acid, base, oxidative, photolytic and thermal stress conditions as per ICH serves to generate degradation products that can be used as a worst case to assess the analytical method performance. The drug showed extensive degradation in thermal, acid, oxidative, base and hydrolytic stress conditions, while it was stable to photolytic degradation conditions. The main degradation product formed under thermal, acid, oxidative, base and hydrolytic stress conditions corresponding to (2R,3R,6S)-N, 6-bis(4-fluorophenyl)-2-(4-hydroxyphenyl)-oxane-3-carboxamide (Ezetimibe tetrahydropyran impurity) was characterized by LC-MS/MS analysis. The degradation products were well resolved from the main peak and its impurities, thus proved the stability-indicating power of the method. The developed method was validated as per

  2. Rapid determination of flavonoids and phenolic acids in grape juices and wines by RP-HPLC/DAD: Method validation and characterization of commercial products of the new Brazilian varieties of grape.

    PubMed

    Padilha, Carla Valéria da Silva; Miskinis, Gabriela Aquino; de Souza, Marcelo Eduardo Alves Olinda; Pereira, Giuliano Elias; de Oliveira, Débora; Bordignon-Luiz, Marilde Terezinha; Lima, Marcos Dos Santos

    2017-08-01

    A method for rapid determination of phenolic compounds by reversed-phase high-performance liquid chromatography (RP-HPLC), using a new column of faster resolution was validated and used to characterize commercial products produced with new grape Brazilian varieties of Northeast of Brazil. The in vitro antioxidant activity was also measured. The method showed linearity (R>0.9995), good precision (CV%<2.78), recovery (91.8-105.1%) and limits of detection (0.04-0.85mgL(-1)) and quantification (0.04-1.41mgL(-1)) according to other methods previously published with the difference of a run time of only 25min. The results obtained in the characterization of the samples differed for juices and wines from other world regions, mainly because of the high values of (-)-epigallocatechin and trans-caftaric acid. The products analyzed showed high antioxidant activity, especially the wine samples with values higher than those from wines of different regions of the world.

  3. Microwave-assisted extraction of herbacetin diglucoside from flax (Linum usitatissimum L.) seed cakes and its quantification using an RP-HPLC-UV system.

    PubMed

    Fliniaux, Ophélie; Corbin, Cyrielle; Ramsay, Aina; Renouard, Sullivan; Beejmohun, Vickram; Doussot, Joël; Falguières, Annie; Ferroud, Clotilde; Lamblin, Frédéric; Lainé, Eric; Roscher, Albrecht; Grand, Eric; Mesnard, François; Hano, Christophe

    2014-03-10

    Flax (Linum usitatissimum L.) seeds are widely used for oil extraction and the cold-pressed flaxseed (or linseed) cakes obtained during this process constitute a valuable by-product. The flavonol herbacetin diglucoside (HDG) has been previously reported as a constituent of the flaxseed lignan macromolecule linked through ester bonds to the linker molecule hydroxymethylglutaric acid. In this context, the development and validation of a new approach using microwave-assisted extraction (MAE) of HDG from flaxseed cakes followed by quantification with a reverse-phase HPLC system with UV detection was purposed. The experimental parameters affecting the HDG extraction yield, such as microwave power, extraction time and sodium hydroxide concentration, from the lignan macromolecule were optimized. A maximum HDG concentration of 5.76 mg/g DW in flaxseed cakes was measured following an irradiation time of 6 min, for a microwave power of 150 W using a direct extraction in 0.1 M NaOH in 70% (v/v) aqueous methanol. The optimized method was proven to be rapid and reliable in terms of precision, repeatability, stability and accuracy for the extraction of HDG. Comparison with a conventional extraction method demonstrated that MAE is more effective and less time-consuming.

  4. Optimization and validation of RP-HPLC-UV method with solid-phase extraction for determination of buparvaquone in human and rabbit plasma: application to pharmacokinetic study.

    PubMed

    Venkatesh, Gantala; Majid, M I A; Ramanathan, S; Mansor, S M; Nair, N K; Croft, Simon L; Navaratnam, V

    2008-05-01

    A simple, sensitive and specific reversed-phase high-performance liquid chromatographic method with UV detection at 251 nm was developed for quantitation of buparvaquone (BPQ) in human and rabbit plasma. The method utilizes 250 microL of plasma and sample preparation involves protein precipitation followed by solid-phase extraction. The method was validated on a C18 column with mobile phase consisting of ammonium acetate buffer (0.02 m, pH 3.0) and acetonitrile in the ratio of 18:82 (v/v) at a flow rate of 1.1 mL/min. The calibration curves were linear (correlation coefficient>or=0.998) in the selected range. The method is specific and sensitive with limit of quantitation of 50 ng/mL for BPQ. The validated method was found to be accurate and precise in the working calibration range. Stability studies were carried out at different storage conditions and BPQ was found to be stable. Partial validation studies were carried out using rabbit plasma and intra- and inter-day precision and accuracy were within 7%. This method is simple, reliable and can be routinely used for preclinical pharmacokinetic studies for BPQ.

  5. Simultaneous determination of domperidone and Itopride in pharmaceuticals and human plasma using RP-HPLC/UV detection: Method development, validation and application of the method in in-vivo evaluation of fast dispersible tablets.

    PubMed

    Khan, Amjad; Iqbal, Zafar; Khadra, Ibrahim; Ahmad, Lateef; Khan, Abad; Khan, Muhammad Imran; Ullah, Zia; Ismail

    2016-03-20

    Domperidone and Itopride are pro-kinetic agents, regulating the gastric motility and are commonly prescribed as anti emetic drugs. In the present study a simple, rapid and sensitive RP-HPLC/UV method was developed for simultaneous determination of Domperidone and Itopride in pharmaceutical samples and human plasma, using Tenofavir as internal standard. Experimental conditions were optimized and method was validated according to the standard guidelines. Combination of water (pH 3.0) and acetonitrile (65:35 v/v) was used as mobile phase, pumped at the flow rate of 1.5 ml/min. Detector wavelength was set at 210 nm and column oven temperature was 40oC. Unlike conventional liquid-liquid extraction, simple precipitation technique was applied for drug extraction from human plasma using acetonitrile for deprotienation. The method showed adequate separation of both the analytes and best resolution was achieved using Hypersil BDS C8 column (150 mm × 4.6 mm, 5 μm). The method was quite linear in the range of 20-600 ng/ml. Recovery of the method was 92.31% and 89.82% for Domperidone and Itopride, respectively. Retention time of both the analytes and internal standard was below 15 min. The lower limit of detection (LLOD) and lower limit of quantification (LLOQ) for Domperidone were 5 and 10 ng/ml while for Itopride was 12 and 15 ng/ml, respectively. The developed method was successfully applied for in-vivo analysis of fast dispersible tablets of Domperidone in healthy human volunteer. The proposed method was a part of formulation development study and was efficiently applied for determination of the two drugs in various pharmaceutical products and human plasma.

  6. Simultaneous determination of vitexin-2"-O-glucoside, vitexin-2"-O-rhamnoside, rutin, and hyperoside in the extract of hawthorn (Crataegus pinnatifida Bge.) leaves by RP-HPLC with ultraviolet photodiode array detection.

    PubMed

    Cheng, Shan; Qiu, Feng; Huang, Jia; He, Junqi

    2007-03-01

    RP-HPLC with UV photodiode array detection (UV-DAD) was developed and validated for the simultaneous determination of vitexin-2"-O-glucoside, vitexin-2"-O-rhamnoside, rutin, and hyperoside in the extract of hawthorn (Crataegus pinnatifida Bge.) leaves. The analytes of interest were separated on a Diamonsil C18 column (250 x 4.6 mm id, 5 microm) with the mobile phase consisting of THF/ACN/methanol/ 0.05% phosphoric acid solution (pH 5.0) (18:1:1:80 v/vl/v). The flow rate was set at 1.0 mL/min and the eluent was detected at 340 nm for the four flavonoids. The method was linear over the studied range of 1.00-100 microg/mL for the four analytes of interest with the correlation coefficient for each analyte greater than 0.999. The LOD and LOQwere 0.03 and 0.10 microg/mL, 0.03 and 0.10 microg/mL, 0.05 and 0.15 pg/mL, 0.10 and 0.30 microg/mL for vitexin-2"-O-glucoside, vitexin-2"-0-rhamnoside, rutin, and hyperoside, respectively. The optimized method was successfully applied to the analysis of four important flavonoids in the extract of hawthorn leaves. The total amounts of the four flavonoids were 22.2, 62.3, 4.27, and 8.24 mg/g dry weight for vitexin-2"-O-glucoside, vitexin-2"-O-rhamnoside, rutin, and hyperoside in the extract of hawthorn leaves, respectively.

  7. Study on determination of iron, cobalt, nickel, copper, zinc and manganese in drinking water by solid-phase extraction and RP-HPLC with 2-(2-quinolinylazo)-5-diethylaminophenol as precolumn derivatizing reagent.

    PubMed

    Hu, Qiufen; Yang, Guanyu; Yang, Jihong; Yin, Jiayuan

    2002-12-01

    A new method for the determination of iron, cobalt, nickel, copper, zinc and manganese in drinking water by the reversed-phase high-performance liquid chromatography (RP-HPLC) with 2-(2-quinolinylazo)-5-diethylaminophenol (QADEAP) as precolumn derivatizing reagent was studied in this paper. The iron, cobalt, nickel, copper, zinc, and manganese ions react with QADEAP to form color chelates in the presence of cetyl trimethylammonium bromide (CTMAB) and acetic acid-sodium acetic buffer solution medium of pH 4.0. These chelates were enriched by solid-phase extraction with a Waters Nova-Pak C18 cartridge and eluted the retained chelates from the cartridge with tetrahydrofuran (THF). The enrichment factor of 100 was achieved. Then the chelates were separated on a Waters Nova-Pak C18 column (3.9 x 150 mm, 5 microm) by gradient elution with methanol (containing 0.2% of acetic acid and 0.1% of CTMAB) and 0.05 mol L(-1) acetic acid-sodium acetic buffer solution (containing 0.1% of CTMAB) (pH 4.0) as mobile phase at a flow rate of 0.5 ml min(-1), and monitored with a photodiode array detector from 450 approximately 700 nm. The detection limits (S/N = 3) of iron, cobalt, nickel, copper, zinc and manganese are 0.8, 1.1, 0.9, 1.1, 1.5 and 2.0 ng L(-1), respectively, in the original sample. This method can be applied to determination at the microg L(-1) level of iron, cobalt, nickel, copper, zinc and manganese in drinking water with good results.

  8. Quantitative and chemical fingerprint analysis for the quality evaluation of Receptaculum Nelumbinis by RP-HPLC coupled with hierarchical clustering analysis.

    PubMed

    Wu, Yan-Bin; Zheng, Li-Jun; Yi, Jun; Wu, Jian-Guo; Chen, Ti-Qiang; Wu, Jin-Zhong

    2013-01-21

    A simple and reliable method of high-performance liquid chromatography with photodiode array detection (HPLC-DAD) was developed to evaluate the quality of Receptaculum Nelumbinis (dried receptacle of Nelumbo nucifera) through establishing chromatographic fingerprint and simultaneous determination of five flavonol glycosides, including hyperoside, isoquercitrin, quercetin-3-O-β-d-glucuronide, isorhamnetin-3-O-β-d-galactoside and syringetin-3-O-β-d-glucoside. In quantitative analysis, the five components showed good regression (R > 0.9998) within linear ranges, and their recoveries were in the range of 98.31%-100.32%. In the chromatographic fingerprint, twelve peaks were selected as the characteristic peaks to assess the similarities of different samples collected from different origins in China according to the State Food and Drug Administration (SFDA) requirements. Furthermore, hierarchical cluster analysis (HCA) was also applied to evaluate the variation of chemical components among different sources of Receptaculum Nelumbinis in China. This study indicated that the combination of quantitative and chromatographic fingerprint analysis can be readily utilized as a quality control method for Receptaculum Nelumbinis and its related traditional Chinese medicinal preparations.

  9. Stability Indices derived from Atmospheric Measurements on a Cable Car

    NASA Astrophysics Data System (ADS)

    Herma, F.; Seidel, J.; Bárdossy, A.

    2012-04-01

    Stability indices are meteorological parameters to describe vertical atmospheric layering and therefore it is possible to predict convective events such as thunderstorms. Commonly, weather balloons with radiosondes are used for the analysis of vertical atmospheric layering. These weather balloons reach high altitudes and atmospheric layering can be determined for the entire troposphere. On the other hand, these balloon ascents are expensive, require the appropriate equipment and permissions and cannot be conducted several times a day on an operational basis. Due to the limitations of the application of weather balloons the unconventional idea came up to equip a cable car with meteorological instruments for vertical profile measurements. To some extent the meteorological instruments had to be customized to the particular requirements and data are transmitted via GSM. The investigated area is a small alpine catchment which is prone to flash floods and thus a reliable forecast for such floods mostly caused by convective rainfall events is important. Therefore the purpose of this contribution is to proof if a cable car can be used for measuring continuous data during the operating hours and whether it is possible to derive reliable conclusions about the stability in the lower troposphere. Several stability indices (e.g. Lifted-, Showalter-, Boyden- and Convective-Index) were investigated. Indices which are calculated on the basis of the "Lifted Parcel Theory" were tested with different approaches to determine the most unstable parcel and therefore the initial values of the required parameters. The derived indices were flagged in active (thunderstorms) and non-active (no thunderstorms) cases. The classification results from available lightning maps in this region. Threshold values were established to distinguish stable, potential indifferent and unstable atmospheric conditions. On the basis of this division pre-warnings for the occurrence of thunderstorms are declared

  10. Stability-Indicating HPLC Determination of Gemcitabine in Pharmaceutical Formulations

    PubMed Central

    Singh, Rahul; Shakya, Ashok K.; Naik, Rajashri; Shalan, Naeem

    2015-01-01

    A simple, sensitive, inexpensive, and rapid stability indicating high performance liquid chromatographic method has been developed for determination of gemcitabine in injectable dosage forms using theophylline as internal standard. Chromatographic separation was achieved on a Phenomenex Luna C-18 column (250 mm × 4.6 mm; 5μ) with a mobile phase consisting of 90% water and 10% acetonitrile (pH 7.00 ± 0.05). The signals of gemcitabine and theophylline were recorded at 275 nm. Calibration curves were linear in the concentration range of 0.5–50 μg/mL. The correlation coefficient was 0.999 or higher. The limit of detection and limit of quantitation were 0.1498 and 0.4541 μg/mL, respectively. The inter- and intraday precision were less than 2%. Accuracy of the method ranged from 100.2% to 100.4%. Stability studies indicate that the drug was stable to sunlight and UV light. The drug gives 6 different hydrolytic products under alkaline stress and 3 in acidic condition. Aqueous and oxidative stress conditions also degrade the drug. Degradation was higher in the alkaline condition compared to other stress conditions. The robustness of the methods was evaluated using design of experiments. Validation reveals that the proposed method is specific, accurate, precise, reliable, robust, reproducible, and suitable for the quantitative analysis. PMID:25838825

  11. A validated stability indicating LC method for oxcarbazepine.

    PubMed

    Pathare, D B; Jadhav, A S; Shingare, M S

    2007-04-11

    The present paper describes the development of a stability indicating reversed phase liquid chromatographic (RPLC) method for oxcarbazepine in the presence of its impurities and degradation products generated from forced decomposition studies. The drug substance was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. The degradation of oxcarbazepine was observed under base hydrolysis. The drug was found to be stable to other stress conditions attempted. Successful separation of the drug from the synthetic impurities and degradation product formed under stress conditions was achieved on a C18 column using mixture of aqueous 0.02 M potassium dihydrogen phosphate-acetonitrile-methanol (45:35:20, v/v/v) as mobile phase. The developed HPLC method was validated with respect to linearity, accuracy, precision, specificity and robustness. The developed HPLC method to determine the related substances and assay determination of oxcarbazepine can be used to evaluate the quality of regular production samples. It can be also used to test the stability samples of oxcarbazepine.

  12. Stability-indicating HPLC method for posaconazole bulk assay.

    PubMed

    Garcia, Cássia V; Costa, Gislaine R; Mendez, Andreas S L

    2012-01-01

    A stability-indicating liquid chromatographic (LC) method was developed for the determination of posaconazole in bulk. Chromatographic separation was achieved using an isocratic elution in a reversed-phase system, with a mobile phase composed of methanol-water (75:25, v/v), at 1.0 mL min(-1) flow. Samples were exposed to degradation under thermal, oxidative and acid/basic conditions, and no interference in the analysis was observed. System suitability was evaluated and results were satisfactory (N = 4,900.00 tailing factor 1.04; RSD between injections = 0.65). The retention time of posaconazole was about 8.5 min and the method was validated within the concentration range 5-60 μg mL(-1) (r = 0.9996). Adequate results were obtained for repeatability (RSD % = 0.86-1.22), inter-day precision (RSD % = 1.21) and accuracy (98.13% mean recovery). Robustness was also determined to be satisfactory after evaluation. The proposed method was successfully applied to posaconazole bulk quantification, showing the method is useful for determination of the drug in routine analysis.

  13. Indicators of dynamic stability in transtibial prosthesis users.

    PubMed

    Kendell, C; Lemaire, E D; Dudek, N L; Kofman, J

    2010-03-01

    An improved understanding of factors related to dynamic stability in lower-limb prosthesis users is important, given the high occurrence of falls in this population. Current methods of assessing stability are unable to adequately characterize dynamic stability over a variety of walking conditions. F-Scan Mobile has been used to collect plantar pressure data and six extracted parameters were useful measures of dynamic stability. The aim of this study was to investigate dynamic stability in individuals with unilateral transtibial amputation based on these six parameters. Twenty community ambulators with a unilateral transtibial amputation walked over level ground, uneven ground, stairs, and a ramp while plantar pressure data were collected. For each limb (intact and prosthetic) and condition, six stability parameters related to plantar center-of-pressure perturbations and gait temporal parameters, were computed from the plantar pressure data. Parameter values were compared between limbs, walking condition, and groups (unilateral transtibial prosthesis users and able-bodied subjects). Differences in parameters were found between limbs and conditions, and between prosthesis users and able-bodied individuals. Further research could investigate optimizing parameter calculations for unilateral transtibial prosthesis users and define relationships between potential for falls and the dynamic stability measures.

  14. Ratio manipulating spectrophotometry versus chemometry as stability indicating methods for cefquinome sulfate determination.

    PubMed

    Yehia, Ali M; Arafa, Reham M; Abbas, Samah S; Amer, Sawsan M

    2016-01-15

    Spectral resolution of cefquinome sulfate (CFQ) in the presence of its degradation products was studied. Three selective, accurate and rapid spectrophotometric methods were performed for the determination of CFQ in the presence of either its hydrolytic, oxidative or photo-degradation products. The proposed ratio difference, derivative ratio and mean centering are ratio manipulating spectrophotometric methods that were satisfactorily applied for selective determination of CFQ within linear range of 5.0-40.0 μg mL(-1). Concentration Residuals Augmented Classical Least Squares was applied and evaluated for the determination of the cited drug in the presence of its all degradation products. Traditional Partial Least Squares regression was also applied and benchmarked against the proposed advanced multivariate calibration. Experimentally designed 25 synthetic mixtures of three factors at five levels were used to calibrate and validate the multivariate models. Advanced chemometrics succeeded in quantitative and qualitative analyses of CFQ along with its hydrolytic, oxidative and photo-degradation products. The proposed methods were applied successfully for different pharmaceutical formulations analyses. These developed methods were simple and cost-effective compared with the manufacturer's RP-HPLC method.

  15. Ratio manipulating spectrophotometry versus chemometry as stability indicating methods for cefquinome sulfate determination

    NASA Astrophysics Data System (ADS)

    Yehia, Ali M.; Arafa, Reham M.; Abbas, Samah S.; Amer, Sawsan M.

    2016-01-01

    Spectral resolution of cefquinome sulfate (CFQ) in the presence of its degradation products was studied. Three selective, accurate and rapid spectrophotometric methods were performed for the determination of CFQ in the presence of either its hydrolytic, oxidative or photo-degradation products. The proposed ratio difference, derivative ratio and mean centering are ratio manipulating spectrophotometric methods that were satisfactorily applied for selective determination of CFQ within linear range of 5.0-40.0 μg mL- 1. Concentration Residuals Augmented Classical Least Squares was applied and evaluated for the determination of the cited drug in the presence of its all degradation products. Traditional Partial Least Squares regression was also applied and benchmarked against the proposed advanced multivariate calibration. Experimentally designed 25 synthetic mixtures of three factors at five levels were used to calibrate and validate the multivariate models. Advanced chemometrics succeeded in quantitative and qualitative analyses of CFQ along with its hydrolytic, oxidative and photo-degradation products. The proposed methods were applied successfully for different pharmaceutical formulations analyses. These developed methods were simple and cost-effective compared with the manufacturer's RP-HPLC method.

  16. Stability-Indicating Method and LC-MS-MS Characterization of Forced Degradation Products of Sofosbuvir.

    PubMed

    Nebsen, M; Elzanfaly, Eman S

    2016-07-19

    Sofosbuvir is a novel direct acting antiviral agent against hepatitis C virus. In the present work, a rapid, specific and reproducible isocratic reversed phase high performance liquid chromatography (RP-HPLC) method has been developed and validated for the determination of sofosbuvir in the presence of its stressed degradation products. Sobosbuvir was subjected to hydrolysis (acidic, alkaline and neutral), oxidation, photolysis and thermal stress, as per international conference on harmonization (ICH) conditions. The drug showed degradation under oxidative, photolysis, acid and base hydrolysis stress conditions. However, it was stable under thermal and neutral hydrolysis stress conditions. Chromatographic separation of the drug from its degradation products was performed on Inertsil ODS-3 C18 (250 mm × 4.6 mm i.d., 5 µm) column using a green mobile phase of methanol:water 70:30 (v/v). The degradation products were characterized by LC-MS-MS and the fragmentation pathways were proposed. The developed method was validated as per ICH guidelines. No previous method was reported regarding the degradation behavior of sofosbuvir.

  17. School Effectiveness Indices Revisited: Cross-Year Stability.

    ERIC Educational Resources Information Center

    Mandeville, Garrett K.

    1988-01-01

    School effectiveness indices based on residuals from regressing test performance onto prior test performance and socioeconomic status were obtained for two consecutive years for 431 elementary schools. The resulting indices were found to be stable, and it was found that grade-within-school effects dominated global school effects. (TJH)

  18. Control sensitivity indices for stability analysis of HVdc systems

    SciTech Connect

    Nayak, O.B.; Gole, A.M.; Chapman, D.G.; Davies, J.B.

    1995-10-01

    This paper presents a new concept called the ``Control Sensitivity Index`` of CSI, for the stability analysis of HVdc converters connected to weak ac systems. The CSI for a particular control mode can be defined as the ratio of incremental changes in the two system variables that are most relevant to that control mode. The index provides valuable information on the stability of the system and, unlike other approaches, aids in the design of the controller. It also plays an important role in defining non-linear gains for the controller. This paper offers a generalized formulation of CSI and demonstrates its application through an analysis of the CSI for three modes of HVdc control. The conclusions drawn from the analysis are confirmed by a detailed electromagnetic transients simulation of the ac/dc system. The paper concludes that the CSI can be used to improve the controller design and, for an inverter in a weak ac system, the conventional voltage control mode is more stable than the conventional {gamma} control mode.

  19. The Stability of School Effectiveness Indices across Years.

    ERIC Educational Resources Information Center

    Mandeville, Garrett K.

    School effectiveness indices (SEIs) based on residuals from regressing test performance in reading and mathematics onto prior-year test performance and a socioeconomic status measure (percentage eligible for a subsidized lunch program) were obtained for two consecutive years for 431 South Carolina elementary schools. The analysis involved school…

  20. Environmental stability of PAH source indices in pyrogenic tars

    SciTech Connect

    Uhler, A.D.; Emsbo-Mattingly, S.D.

    2006-04-15

    Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants found in soil, sediments, and airborne particulates. The majority of PAHs found in modern soils and sediments arise from myriad anthropogenic petrogenic and pyrogenic sources. Tars and tar products such as creosote produced from the industrial pyrolysis of coal or oil at former manufactured gas plants (MGPs) or in coking retorts are viscous, oily substances that contain significant concentrations of PAH, usually in excess of 30% w/w. Pyrogenic tars and tar products have unique PAH patterns (source signatures) that are a function of their industrial production. Among pyrogenic materials, certain diagnostic ratios of environmentally recalcitrant 4-, 5- and 6-ring PAHs have been identified as useful environmental markers for tracking the signature of tars and petroleum in the environment. The use of selected PAH source ratios is based on the concept that PAHs with similar properties (i.e., molecular weight, partial pressure, solubility, partition coefficients, and biotic/abiotic degradation) will weather at similar rates in the environment thereby yielding stable ratios. The stability of more than 30 high molecular weight PAH ratios is evaluated during controlled studies of tar evaporation and aerobic biodegradation. The starting materials in these experiments consisted of relatively unweathered tars derived from coal and petroleum, respectively. The PAH ratios from these laboratory studies are compared to those measured in PAH residues found in tar-contaminated soils at a former MGP that operated with a carburetted water gas process.

  1. Geometrical analysis of the LiCN vibrational dynamics: a stability geometrical indicator.

    PubMed

    Vergel, A; Benito, R M; Losada, J C; Borondo, F

    2014-02-01

    The vibrational dynamics of the LiNC/LiCN molecular system is examined making use of the Riemannian geometry. Stability and chaoticity are analyzed, in this context, by means of the Jacobi-Levi-Civita equations, derived from the Jacobi metric, and its solutions. A dynamical indicator, called stability geometrical indicator, is introduced in order to ascertain the dynamical characteristics of stability and chaos in the molecule under study.

  2. Stabilities of neutral and basic esters of bendamustine in plasma compared to the parent compound: kinetic investigations by HPLC.

    PubMed

    Huber, S; Antoni, F; Schickaneder, C; Schickaneder, H; Bernhardt, G; Buschauer, A

    2015-02-01

    Esters of the cytostatic bendamustine (1), previously demonstrated to be much more potent than the parent compound as antiproliferative agents in vitro, were investigated for stability in buffer and plasma, as well as against porcine liver esterase in the presence of different amounts of albumin using a validated RP-HPLC method with fluorescence detection. The hydrolysis of the nitrogen mustard moiety was retarded (for 1: approximately 130 vs. 11 min) in the presence of plasma proteins. For the derivatives, both cleavage of ester and nitrogen mustard moieties were analyzed. Enzymatic hydrolysis was very fast in the case of 2-pyrrolidino-, 2-piperidino- and 2-(4-methylpiperazino)-ethyl esters, whereas methyl, ethyl, morpholinoethyl and branched 2-pyrrolidinoethyl esters were considerably more stable (half-lives between 41 and 116 min, compared to <5 min). Inhibition by physostigmine indicated unspecific cholinesterases to be involved in the rapid ester cleavage. Due to lower protein content and higher enzymatic activity in murine compared to human plasma, reduced stability of all investigated esters in mouse plasma (t½<2 min) has to be taken into account with respect to the design of animal studies.

  3. Evaluation of oxygen utilization as an indicator of municipal solid-waste compost stability

    SciTech Connect

    Zimmerman, R.A.

    1991-01-01

    This research evaluated oxygen utilization parameters as indicators of MSW compost stability. Parameters evaluated were the oxygen utilization rate (OUR), specific oxygen uptake rate (SOUR), five-day biochemical oxygen demand, and chemical oxygen demand. In addition, other suggested indicators of stability were investigated including percent volatile solids, volatile solids reduction, nitrogen content, carbon: nitrogen ratio, and reheating potential (RP). OUR is a measure of the rate of oxygen utilization by the microorganisms in the decomposition of organic matter in compost. OUR was observed to be sensitive to the degree of stabilization and decreased with increasing compost age and stability. OUR values near zero indicate that the compost microorganisms are in a state of endogenous respiration, which is characteristic of a stable compost. Therefore, OUR is an excellent indicator of stability. A number of disadvantages are associated with OUR for practical application. Therefore, other parameters were evaluated as indicators of stability based on their statistical correlation to OUR. RP exhibited the strongest correlation to OUR. In combination, RP and SOUR were the two parameters which exhibited the strongest correlation to OUR. OUR, RP, and SOUR are all measures of microbial activity which reflect the degree of organic decomposition, and therefore, stability. Based on the results of this research; OUR, RP, and SOUR are useful parameters in assessing compost stability.

  4. Optimal Placement of Unified Power Flow Controllers to Improve Dynamic Voltage Stability Using Power System Variable Based Voltage Stability Indices

    PubMed Central

    Albatsh, Fadi M.; Ahmad, Shameem; Mekhilef, Saad; Mokhlis, Hazlie; Hassan, M. A.

    2015-01-01

    This study examines a new approach to selecting the locations of unified power flow controllers (UPFCs) in power system networks based on a dynamic analysis of voltage stability. Power system voltage stability indices (VSIs) including the line stability index (LQP), the voltage collapse proximity indicator (VCPI), and the line stability index (Lmn) are employed to identify the most suitable locations in the system for UPFCs. In this study, the locations of the UPFCs are identified by dynamically varying the loads across all of the load buses to represent actual power system conditions. Simulations were conducted in a power system computer-aided design (PSCAD) software using the IEEE 14-bus and 39- bus benchmark power system models. The simulation results demonstrate the effectiveness of the proposed method. When the UPFCs are placed in the locations obtained with the new approach, the voltage stability improves. A comparison of the steady-state VSIs resulting from the UPFCs placed in the locations obtained with the new approach and with particle swarm optimization (PSO) and differential evolution (DE), which are static methods, is presented. In all cases, the UPFC locations given by the proposed approach result in better voltage stability than those obtained with the other approaches. PMID:25874560

  5. Optimal placement of unified power flow controllers to improve dynamic voltage stability using power system variable based voltage stability indices.

    PubMed

    Albatsh, Fadi M; Ahmad, Shameem; Mekhilef, Saad; Mokhlis, Hazlie; Hassan, M A

    2015-01-01

    This study examines a new approach to selecting the locations of unified power flow controllers (UPFCs) in power system networks based on a dynamic analysis of voltage stability. Power system voltage stability indices (VSIs) including the line stability index (LQP), the voltage collapse proximity indicator (VCPI), and the line stability index (Lmn) are employed to identify the most suitable locations in the system for UPFCs. In this study, the locations of the UPFCs are identified by dynamically varying the loads across all of the load buses to represent actual power system conditions. Simulations were conducted in a power system computer-aided design (PSCAD) software using the IEEE 14-bus and 39- bus benchmark power system models. The simulation results demonstrate the effectiveness of the proposed method. When the UPFCs are placed in the locations obtained with the new approach, the voltage stability improves. A comparison of the steady-state VSIs resulting from the UPFCs placed in the locations obtained with the new approach and with particle swarm optimization (PSO) and differential evolution (DE), which are static methods, is presented. In all cases, the UPFC locations given by the proposed approach result in better voltage stability than those obtained with the other approaches.

  6. Development of new method for simultaneous analysis of piracetam and levetiracetam in pharmaceuticals and biological fluids: application in stability studies.

    PubMed

    Siddiqui, Farhan Ahmed; Sher, Nawab; Shafi, Nighat; Wafa Sial, Alisha; Ahmad, Mansoor; Mehjebeen; Naseem, Huma

    2014-01-01

    RP-HPLC ultraviolet detection simultaneous quantification of piracetam and levetiracetam has been developed and validated. The chromatography was obtained on a Nucleosil C18 column of 25 cm×0.46 cm, 10 μm, dimension. The mobile phase was a (70:30 v/v) mixture of 0.1 g/L of triethylamine and acetonitrile. Smooth flow of mobile phase at 1 mL/min was set and 205 nm wavelength was selected. Results were evaluated through statistical parameters which qualify the method reproducibility and selectivity for the quantification of piracetam, levetiracetam, and their impurities hence proving stability-indicating properties. The proposed method is significantly important, permitting the separation of the main constituent piracetam from levetiracetam. Linear behavior was observed between 20 ng/mL and 10,000 ng/mL for both drugs. The proposed method was checked in bulk drugs, dosage formulations, physiological condition, and clinical investigations and excellent outcome was witnessed.

  7. Development of New Method for Simultaneous Analysis of Piracetam and Levetiracetam in Pharmaceuticals and Biological Fluids: Application in Stability Studies

    PubMed Central

    Siddiqui, Farhan Ahmed; Sher, Nawab; Shafi, Nighat; Wafa Sial, Alisha; Ahmad, Mansoor; Mehjebeen

    2014-01-01

    RP-HPLC ultraviolet detection simultaneous quantification of piracetam and levetiracetam has been developed and validated. The chromatography was obtained on a Nucleosil C18 column of 25 cm × 0.46 cm, 10 μm, dimension. The mobile phase was a (70 : 30 v/v) mixture of 0.1 g/L of triethylamine and acetonitrile. Smooth flow of mobile phase at 1 mL/min was set and 205 nm wavelength was selected. Results were evaluated through statistical parameters which qualify the method reproducibility and selectivity for the quantification of piracetam, levetiracetam, and their impurities hence proving stability-indicating properties. The proposed method is significantly important, permitting the separation of the main constituent piracetam from levetiracetam. Linear behavior was observed between 20 ng/mL and 10000 ng/mL for both drugs. The proposed method was checked in bulk drugs, dosage formulations, physiological condition, and clinical investigations and excellent outcome was witnessed. PMID:25114921

  8. Two Approaches to Examining the Stability of Myers-Briggs Type Indicator Scores

    ERIC Educational Resources Information Center

    Salter, Daniel W.; Forney, Deanna S.; Evans, Nancy J.

    2005-01-01

    In this study, two approaches are used to assess the stability of Myers-Briggs Type Indicator scores across 3 administrations (N = 231): longitudinal configural frequency analysis with categorical scores and generalizability theory with the Preference Clarity Indices and continuous scores. The results are generally positive. Evaluation of…

  9. Subtle alternating electrocardiographic morphology as an indicator of decreased cardiac electrical stability

    NASA Technical Reports Server (NTRS)

    Smith, J. M.; Blue, B.; Clancy, E.; Valeri, C. R.; Cohen, R. J.

    1985-01-01

    Observations from finite-element computer models, together with analytic developments based on percolation theory have suggested that subtle fluctuations of ECG morphology might serve as an indicator diminished cardiac electrical stability. With fixed-rate atrial pacing in canines, we have previously observed a pattern of alternation in T wave energy which correlated with cardiac electrical stability. We report here on a series of 20 canine experiments in which cardiac electrical stability (measured via Ventricular Fibrillation Threshold determination) was compared to a non-degenerate, multidimensional measurement of the degree of alternating activity present in the ECG complex morphology. The decrease in cardiac electrical stability brought on by both coronary artery occlusion and systemic hypothermia was consistently accompanied by subtle alternation in ECG morphology, with the absolute degree of alternating activity being significantly (negatively) correlated with cardiac electrical stability.

  10. Characterization, thermal stability studies, and analytical method development of Paromomycin for formulation development.

    PubMed

    Khan, Wahid; Kumar, Neeraj

    2011-06-01

    Paromomycin (PM) is an aminoglycoside antibiotic, first isolated in the 1950s, and approved in 2006 for treatment of visceral leishmaniasis. Although isolated six decades back, sufficient information essential for development of pharmaceutical formulation is not available for PM. The purpose of this paper was to determine thermal stability and development of new analytical method for formulation development of PM. PM was characterized by thermoanalytical (DSC, TGA, and HSM) and by spectroscopic (FTIR) techniques and these techniques were used to establish thermal stability of PM after heating PM at 100, 110, 120, and 130 °C for 24 h. Biological activity of these heated samples was also determined by microbiological assay. Subsequently, a simple, rapid and sensitive RP-HPLC method for quantitative determination of PM was developed using pre-column derivatization with 9-fluorenylmethyl chloroformate. The developed method was applied to estimate PM quantitatively in two parenteral dosage forms. PM was successfully characterized by various stated techniques. These techniques indicated stability of PM for heating up to 120 °C for 24 h, but when heated at 130 °C, PM is liable to degradation. This degradation is also observed in microbiological assay where PM lost ∼30% of its biological activity when heated at 130 °C for 24 h. New analytical method was developed for PM in the concentration range of 25-200 ng/ml with intra-day and inter-day variability of < 2%RSD. Characterization techniques were established and stability of PM was determined successfully. Developed analytical method was found sensitive, accurate, and precise for quantification of PM. Copyright © 2010 John Wiley & Sons, Ltd.

  11. Octanol/water partitioning simulation by RP-HPLC for structurally diverse acidic drugs: comparison of three columns in the presence and absence of n-octanol as the mobile phase additive.

    PubMed

    Giaginis, Costas; Theocharis, Stamatios; Tsantili-Kakoulidou, Anna

    2013-12-01

    The advantageous effect of n-octanol as a mobile phase additive for lipophilicity assessment of structurally diverse acidic drugs both in the neutral and ionized form was explored. Two RP C18 columns, ABZ+ and Aquasil, were used for the determination of logkw indices, and the results were compared with those previously reported on a base-deactivated silica column. At pH 2.5, the use of n-octanol-saturated buffer as the mobile phase aqueous component led to high-quality 1:1 correlation between logkw and logP for the ABZ+ column, while inferior statistics were obtained for Aquasil. At physiological pH, the correlations were significantly improved if strongly ionized acidic drugs were treated separately from weakly ionized ones. In the latter case, 1:1 correlations between logD7.4 and logkw(oct) indices were obtained in the presence of 0.25% n-octanol. Concerning strongly ionized compounds, adequate correlations were established under the same conditions; however, slopes were significantly lower than unity, while large negative intercepts were obtained. According to the absolute difference (diff = logD7.4 – logkw) pattern, base-deactivated silica showed a better performance than ABZ+, however, the latter seems more efficient for the lipophilicity assessment of highly lipophilic acidic compounds. Aquasil may be the column of choice if logD7.4<3 with the limitation, however, that very hydrophilic compounds cannot be measured.

  12. The Effect of Ankle Taping and Balance Exercises on Postural Stability Indices in Healthy Women

    PubMed Central

    Akbari, Asghar; Sarmadi, Alireza; Zafardanesh, Parisa

    2014-01-01

    [Purpose] The purpose of this study was to compare the effect of ankle taping and balance exercises on postural stability indices in healthy women. [Subjects and Methods] Thirty healthy female students were randomly assigned into two equal groups: ankle taping and balance exercise. The balance exercise group performed balance exercises for 6 weeks, with 3 sessions per week and each session lasting 40 minutes. Ankle joint taping was performed for 6 weeks and was renewed three times a week. Before and after the interventions, overall, anteroposterior, and mediolateral stability indices were measured with a Biodex Balance System in bilateral and unilateral stance positions with the eyes open and closed. [Results] In the taping group during bilateral standing with the eyes closed, the overall stability index changed from 6±1.4 to 4.8±1.3, anteroposterior stability index changed from 4.2±1.27 to 3.4±0.97, and mediolateral stability index changed from 3.2±0.75 to 2.7± 0.7. In the balance exercise group during bilateral standing with the eyes closed, the overall stability index changed from 5.7±1.69 to 4.5±1.94, anteroposterior stability index changed from 4.1±1.61 to 3±1.21, and mediolateral stability index changed from 3.5±1.4 to 2.2± 1.3. No significant difference was seen between the two groups regarding any study variables. [Conclusion] The results showed that compared with the taping technique, balance training increases postural stability in the majority of the studied balance situations. PMID:24926148

  13. Degradation Study on Sulfasalazine and a Validated HPLC-UV Method for its Stability Testing.

    PubMed

    Saini, Balraj; Bansal, Gulshan

    2014-01-01

    Sulfasalazine (SSZ) was subjected to degradation under the conditions of hydrolysis (acid, alkali, and water), oxidation (30% H2O2), dry heat, and photolysis (UV-VIS light) in accordance with the ICH guidelines. An RP-HPLC method was developed to study the degradation behavior. No degradation was noted under any condition except alkaline hydrolysis where SSZ was degraded to a single minor product. SSZ was optimally resolved from this product on an XTerra(®) RP18 column with a mobile phase composed of methanol and an ammonium acetate buffer (10 mM, pH 7.0) (48:52, v/v) delivered at a rate of 0.8 mL/min in an isocratic mode. The method was validated and found to be linear (r(2)=0.99945), precise (%RSD <2), robust, and accurate (94-102%) in the concentration range of 0.5-50 μg/mL of SSZ. The PDA analysis of the degraded sample revealed the SSZ peak purity to be 998.99 and the drug peak eluted with a resolution factor of >2 from the nearest resolving peak, indicating the method to be selectively stability-indicating for the drug analysis. The method was applied successfully for the stability testing of the commercially available SSZ tablets that were under varied ICH-prescribed conditions. An explanation for the unusual stability of the drug when exposed to acidic hydrolysis, despite the presence of the sulfonamide linkage, is also discussed.

  14. LC and LC-MS/MS study of forced decomposition behavior of anastrozole and establishment of validated stability-indicating analytical method for impurities estimation in low dose anastrozole tablets.

    PubMed

    Reddy, Y Ramachandra; Nandan, Srinivasan R; Bharathi, D Vijaya; Nagaraju, B; Reddy, S Saidu; Ravindranath, L K; Rao, V Suryanarayan

    2009-10-15

    Anastrozole tablets were subjected to different ICH prescribed stress conditions of thermal, hydrolysis, humidity, photolysis and oxidation stress. The drug was found to be stable for all the stressed conditions except for oxidation. Separation of anastrozole from its potential impurities, degradation products and five anastrozole related compounds as main impurities were achieved on Inertsil ODS-3V, 250 mm x 4.6 mm i.d, 5 microm analytical column using reversed phase high performance liquid chromatography (RP-HPLC). The elution of impurities employed time dependent gradient programmed mobile phase consisting of water as mobile phase-A and acetonitrile as mobile phase-B at column flow rates of 1 ml/min and at 215 nm UV detection. The same method was also extended to LC-MS/MS studies which were carried out to identify the degradation product. The method developed was established to have sufficient intermediate precision as similar separation was achieved on another instrument handled by a different operator. The LOQ for anastrozole related compound-A (RC-A), related compound-B (RC-B), related compound-C (RC-C), related compound-D (RC-D), related compound-E (RC-E) and anastrozole were 0.05, 0.03, 0.03, 0.06, 0.06 and 0.06 microg ml(-1) respectively. The linearity of the proposed method for all the above related compounds was investigated in the range of LOQ to 0.600 microg ml(-1) respectively. The specificity was established through peak purity testing using a photo-diode array detector. Method was validated according to ICH guidelines and statistical analysis of the data proved to be suitable for stability testing at quality control.

  15. The effects of gait strategy on metabolic rate and indicators of stability during downhill walking.

    PubMed

    Monsch, E D; Franz, C O; Dean, J C

    2012-07-26

    When walking at a given speed, humans often appear to prefer gait patterns that minimize metabolic rate, thereby maximizing metabolic economy. However, recent experiments have demonstrated that humans do not maximize economy when walking downhill. The purpose of this study was to investigate whether this non-metabolically optimal behavior is the result of a trade-off between metabolic economy and gait stability. We hypothesized that humans have the ability to modulate their gait strategy to increase either metabolic economy or stability, but that increase in one measure will be accompanied by decrease in the other. Subjects walked downhill using gait strategies ranging from risky to conservative, which were either prescribed by verbal instructions or induced by the threat of perturbations. We quantified spatiotemporal gait characteristics, metabolic rate and several indicators of stability previously associated with fall risk: stride period variability; step width variability; Lyapunov exponents; Floquet multipliers; and stride period fractal index. When subjects walked using conservative gait strategies, stride periods and lengths decreased, metabolic rate increased, and anteroposterior maximum Lyapunov exponents increased, which has previously been interpreted as an indicator of decreased stability. These results do not provide clear support for the proposed trade-off between economy and stability, particularly when stability is approximated using complex metrics. However, several gait pattern changes previously linked to increased fall risk were observed when our healthy subjects walked with a conservative strategy, suggesting that these changes may be a response to, rather than a cause of, increased fall risk.

  16. RP-HPLC-ESI-MS evidenced that salivary cystatin B is detectable in adult human whole saliva mostly as S-modified derivatives: S-Glutathionyl, S-cysteinyl and S-S 2-mer.

    PubMed

    Cabras, Tiziana; Manconi, Barbara; Iavarone, Federica; Fanali, Chiara; Nemolato, Sonia; Fiorita, Antonella; Scarano, Emanuele; Passali, Giulio Cesare; Manni, Armando; Cordaro, Massimo; Paludetti, Gaetano; Faa, Gavino; Messana, Irene; Castagnola, Massimo

    2012-01-04

    An HPLC-ESI-MS analysis of adult human whole saliva evidenced three protein masses (M average 11,487±2, 11,301±2 and 22,362±3Da) eluting in the 32.5-35.0min range. Treatment in reducing conditions allowed establishing that they are S-derivatives of N-terminal acetylated cystatin B, namely its S-glutathionyl, S-cysteinyl and S-S dimer. The identification was confirmed by high resolution HPLC-ESI-MS-MS experiments on the intact naturally occurring proteins and their tryptic digests. S-unmodified cystatin B is rarely detectable in whole saliva of healthy adults (5 subjects out of 65) and its percentage does not overcome approximately 20% of total cystatin B (11±9%). In the majority of subjects (60 out of 65) the mean percentages of the S-modified derivatives were S-glutathionyl 53±13%, S-cysteinyl 15±5%, S-S 2-mer 32±13%. Variations of the percentages of these S-modified derivatives of cystatin B could be indicative of oral oxidative stress. As we are aware, this is the first time that S-glutathionylation and S-cysteinylation were described as extensive PTM of a salivary protein and the first time that these PTMs were detected in naturally occurring cystatin B.

  17. RP-HPLC characterization of lupenone and β-sitosterol in rhizoma musae and evaluation of the anti-diabetic activity of lupenone in diabetic Sprague-Dawley rats.

    PubMed

    Xu, Feng; Wu, Hongmei; Wang, Xiangpei; Yang, Ye; Wang, Yuanmin; Qian, Haibing; Zhang, Yanyan

    2014-09-09

    With the aim of characterizing the active ingredients lupenone and β-sitosterol in Rhizoma Musae samples a reversed-phase HPLC method for the separation of these two compounds in Rhizoma Musae samples was developed (regression coefficient>0.9996). The method was further applied to quantify lupenone and β-sitosterol content in Rhizoma Musae samples cultured in different growth environments. Different variables such as geographical location, growth stage, and harvest time, demonstrated differential effects on lupenone and β-sitosterol levels. Moreover, we determined the optimum conditions for cultivation and harvesting of Rhizoma Musae herbs. Lupenone administration caused a significant reduction in fasting blood glucose (FBG) levels in diabetic rats at doses of 1.78, 5.33, and 16.00 mg·kg⁻¹·day⁻¹ for 14 days, the glycated hemoglobin (HbA1c) levels of diabetic rats also significantly reduced at doses of 5.33, and 16.00 mg·kg⁻¹·day⁻¹, indicating a robust antidiabetic activity. To our knowledge, this is the first report of an optimized HPLC method successfully applied to quantify lupenone and β-sitosterol, and its applicability in optimizing Rhizoma Musae growth. Animal experiments also showed for the first time that lupenone from Rhizoma Musae has anti-diabetic activity.

  18. Separation of kafirins on surface porous RP-HPLC columns

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surface porous HPLC columns were investigated for the separation of kafarins, storage proteins of grain sorghum. Kafirins were successfully separated using C3, C8 and C18 surface porous stationary phases in less than 17 min. Separations using a monolithic C18 stationary phase were also developed ...

  19. Levodopa microparticles for pulmonary delivery: photodegradation kinetics and LC stability-indicating method.

    PubMed

    Pereira, R L; Paim, C S; Barth, A B; Raffin, R P; Guterres, S S; Schapoval, E E S

    2012-07-01

    Levodopa, (S)-2-amino-3-(3,4-dihydroxyphenyl) propanoic acid, is still considered the gold standard treatment for Parkinson's disease. However, oral levodopa shows poor pharmacokinetics and its efficacy becomes problematic with the progression of the disease. Pulmonary delivery using the association of the polymers: chitosan, hyaluronic acid and HPMC, represents a novel approach to overcome this problem. A stability-indicating liquid chromatography method for the quantitative determination of levodopa microparticles for pulmonary delivery was developed as well as its photodegradation kinetics in solution. The developed and validated method was applied for the analyses of the novel formulation as well as for protocols of stability studies.

  20. Stability indicating simplified HPLC method for simultaneous analysis of resveratrol and quercetin in nanoparticles and human plasma.

    PubMed

    Kumar, Sandeep; Lather, Viney; Pandita, Deepti

    2016-04-15

    Resveratrol and quercetin are well-known polyphenolic compounds present in common foods, which have demonstrated enormous potential in the treatment of a wide variety of diseases. Owing to their exciting synergistic potential and combination delivery applications, we developed a simple and rapid RP-HPLC method based on isosbestic point detection. The separation was carried out on phenomenex Synergi 4μ Hydro-RP 80A column using methanol: acetonitrile (ACN): 0.1% phosphoric acid (60:10:30) as mobile phase. The method was able to quantify nanograms of analytes simultaneously on a single wavelength (269 nm), making it highly sensitive, rapid as well as economical. Additionally, forced degradation studies of resveratrol and quercetin were established and the method's applicability was evaluated on PLGA nanoparticles and human plasma. The analytes peaks were found to be well resolved in the presence of degradation products and excipients. The simplicity of the developed method potentializes its suitability for routine in vitro and in vivo analysis of resveratrol and quercetin.

  1. Development and Validation of Stability-indicating High Performance Liquid Chromatographic Method for the Estimation of Everolimus in Tablets

    PubMed Central

    Sharmila, D.; Rao, A. Lakshmana; Kalyani, L.

    2015-01-01

    The present study depicts the development of a validated reversed-phase high performance liquid chromatographic method for the determination of the everolimus in presence of degradation products or pharmaceutical excipients. Stress study was performed on everolimus and it was found that it degrade sufficiently in oxidizing and acidic conditions but less degradation was found in alkaline, neutral, thermal and photolytic conditions. The separation was carried out on Hypersil BDS C18 column (100×4.6 mm, 5 μ) column having particle size 5 μ using acetate buffer:acetonitrile (50:50 v/v) with pH 6.5 adjusted with orthophosphoric acid as mobile phase at flow rate of 1 ml/min. The wavelength of the detection was 280 nm. A retention time (Rt) nearly 3.110 min was observed. The calibration curve for everolimus was linear (r2=0.999) from range of 25-150 μg/ml with limit of detection and limit of quantification of 0.036 μg/ml and 0.109 μg/ml, respectively. Analytical validation parameters such as selectivity, specificity, linearity, accuracy and precision were evaluated and relative standard deviation value for all the key parameters were less than 2.0%. The recovery of the drug after standard addition was found to be 100.55%. Thus, the developed RP-HPLC method was found to be suitable for the determination of everolimus in tablets containing various excipients. PMID:26798176

  2. Certain Actions from the Functional Movement Screen Do Not Provide an Indication of Dynamic Stability

    PubMed Central

    Lockie, Robert G.; Callaghan, Samuel J.; Jordan, Corrin A.; Luczo, Tawni M.; Jeffriess, Matthew D.; Jalilvand, Farzad; Schultz, Adrian B.

    2015-01-01

    Dynamic stability is an essential physical component for team sport athletes. Certain Functional Movement Screen (FMS) exercises (deep squat; left- and right-leg hurdle step; left- and right-leg in-line lunge [ILL]; left- and right-leg active straight-leg raise; and trunk stability push-up [TSPU]) have been suggested as providing an indication of dynamic stability. No research has investigated relationships between these screens and an established test of dynamic stability such as the modified Star Excursion Balance Test (mSEBT), which measures lower-limb reach distance in posteromedial, medial, and anteromedial directions, in team sport athletes. Forty-one male and female team sport athletes completed the screens and the mSEBT. Participants were split into high-, intermediate-, and low-performing groups according to the mean of the excursions when both the left and right legs were used for the mSEBT stance. Any between-group differences in the screens and mSEBT were determined via a one-way analysis of variance with Bonferroni post hoc adjustment (p < 0.05). Data was pooled for a correlation analysis (p < 0.05). There were no between-group differences in any of the screens, and only two positive correlations between the screens and the mSEBT (TSPU and right stance leg posteromedial excursion, r = 0.37; left-leg ILL and left stance leg posteromedial excursion, r = 0.46). The mSEBT clearly indicated participants with different dynamic stability capabilities. In contrast to the mSEBT, the selected FMS exercises investigated in this study have a limited capacity to identify dynamic stability in team sport athletes. PMID:26557187

  3. Comparison of aerobic and anaerobic stability indices through a MSW biological treatment process.

    PubMed

    Ponsá, Sergio; Gea, Teresa; Alerm, Llorenç; Cerezo, Javier; Sánchez, Antoni

    2008-12-01

    A complex mechanical-biological waste treatment plant designed for the processing of mixed municipal solid wastes (MSW) and source-selected organic fraction of municipal solid wastes (OFMSW) has been studied by using stability indices related to aerobic (respiration index, RI) and anaerobic conditions (biochemical methane potential, BMP). Several selected stages of the plant have been characterized: waste inputs, mechanically treated wastes, anaerobically digested materials and composted wastes, according to the treatment sequence used in the plant. Results obtained showed that the main stages responsible for waste stabilization were the two first stages: mechanical separation and anaerobic digestion with a diminution of both RI and BMP around 40% and 60%, respectively, whereas the third stage, composting of digested materials, produced lesser biological degradation (20-30%). The results related to waste stabilization were similar in both lines (MSW and OFMSW), although the indices obtained for MSW were significantly lower than those obtained for OFMSW, which demonstrated a high biodegradability of OFMSW. The methodology proposed can be used for the characterization of organic wastes and the determination of the efficiency of operation units used in mechanical-biological waste treatment plants.

  4. Best Practices in Stability Indicating Method Development and Validation for Non-clinical Dose Formulations.

    PubMed

    Henry, Teresa R; Penn, Lara D; Conerty, Jason R; Wright, Francesca E; Gorman, Gregory; Pack, Brian W

    2016-11-01

    Non-clinical dose formulations (also known as pre-clinical or GLP formulations) play a key role in early drug development. These formulations are used to introduce active pharmaceutical ingredients (APIs) into test organisms for both pharmacokinetic and toxicological studies. Since these studies are ultimately used to support dose and safety ranges in human studies, it is important to understand not only the concentration and PK/PD of the active ingredient but also to generate safety data for likely process impurities and degradation products of the active ingredient. As such, many in the industry have chosen to develop and validate methods which can accurately detect and quantify the active ingredient along with impurities and degradation products. Such methods often provide trendable results which are predictive of stability, thus leading to the name; stability indicating methods. This document provides an overview of best practices for those choosing to include development and validation of such methods as part of their non-clinical drug development program. This document is intended to support teams who are either new to stability indicating method development and validation or who are less familiar with the requirements of validation due to their position within the product development life cycle.

  5. Stability-indicating LC method for the simultaneous determination of lisinopril and hydrochlorothiazide.

    PubMed

    de Diego, Marta; Soto, Jorge; Mennickent, Sigrid

    2014-01-01

    A simple and rapid stability-indicating liquid chromatographic method was developed and validated for the simultaneous determination of lisinopril and hydrochlorotiazide (HCTZ) in drug substances and dosage forms in the presence of degradation products. Forced degradation studies were conducted on the pure drugs under hydrolytic, oxidative, thermal and photolytic conditions. A chromatographic separation of the two drugs and its degradation products was achieved with an RP-18 column, using methanol, acetonitrile and phosphate buffer (pH 7.1; 0.05 M) (15:15:70, v/v/v) as mobile phase at a flow rate of 0.8 mL min(-1) and UV detection at 210 nm. Lisinopril and HCTZ were well resolved from its degradation products showing the stability-indicating capability of the method. The described method was linear over a range of 40-200 µg mL(-1) for lisinopril and 25-175 µg mL(-1) for HCTZ. The assay was also selective, accurate and precise for lisinopril and HCTZ determination. This method represents an alternative to the United States Pharmacopeia (USP) method showing shorter retention time. The method was successfully applied for determination of lisinopril and HCTZ in combined commercial tablets. The results showed that the proposed method was found to be suitable for quantitative determination and the stability study of lisinopril and HCTZ in pharmaceutical samples.

  6. Soil aggregate stability as an indicator for eco-engineering effectiveness?

    NASA Astrophysics Data System (ADS)

    Graf, Frank

    2015-04-01

    Eco-engineering aims at stabilising soil and slopes by applying technical and biological measures. Engineering structures are commonly well defined, immediately usable and operative, and their stability effects quantifiable and verifiable. Differently, the use of plants requires more restrictive boundary conditions and the protection potential is rarely easily calculable and develop-ing as a function of growth rate. Although the use of vegetation is widely appreciated and their stabilising effect recognised, there is an increasing demand on sound facts on its efficiency, in particular, in relation to time. Conclusively, a certain necessity has been recognised to monitor, assess and quantify the effectiveness of ecological restora-tion measures in order to facilitate the transfer of technology and knowledge. Recent theoretical models emphasize the im-portance of taking an integrated monitoring approach that considers multiple variables. However, limited financial and time resources often prevent such comprehensive assessments. A solution to this problem may be to use integrated indicators that reflect multiple aspects and, therefore, allow extensive information on ecosystem status to be gathered in a relatively short time. Among various other indicators, such as fractal dimension of soil particle size distribution or microbiological parameters, soil aggregate stability seems the most appropriate indicator with regard to protecting slopes from superficial soil failure as it is critical to both plant growth and soil structure. Soil aggregation processes play a crucial role in re-establishing soil structure and function and, conclusively, for successful and sustainable re-colonisation. Whereas the key role of soil aggregate stability in ecosystem functioning is well known concerning water, gas, and nutrient fluxes, only limited information is available with regard to soil mechanical and geotechnical aspects. Correspondingly, in the last couple of years several studies

  7. PrimeSupplier Cross-Program Impact Analysis and Supplier Stability Indicator Simulation Model

    NASA Technical Reports Server (NTRS)

    Calluzzi, Michael

    2009-01-01

    PrimeSupplier, a supplier cross-program and element-impact simulation model, with supplier solvency indicator (SSI), has been developed so that the shuttle program can see early indicators of supplier and product line stability, while identifying the various elements and/or programs that have a particular supplier or product designed into the system. The model calculates two categories of benchmarks to determine the SSI, with one category focusing on agency programmatic data and the other focusing on a supplier's financial liquidity. PrimeSupplier was developed to help NASA smoothly transition design, manufacturing, and repair operations from the Shuttle program to the Constellation program, without disruption in the industrial supply base.

  8. Gas Generation Rates as an Indicator for the Long Term Stability of Radioactive Waste Products

    SciTech Connect

    Steyer, S.; Brennecke, P.; Bandt, G.; Kroger, H.

    2007-07-01

    Pursuant to the 'Act on the Peaceful Utilization of Atomic Energy and the Protection against its Hazards' (Atomic Energy Act) the Federal Office for Radiation Protection (Bundesamt fuer Strahlenschutz, BfS) is legally responsible for the construction and operation of federal facilities for the disposal of radioactive waste. Within the scope of this responsibility, particular due to par. 74(1) Ordinance on Radiation Protection, BfS defines all safety-related requirements on waste packages envisaged for disposal, establishes guidelines for the conditioning of radioactive waste and approves the fulfillment of the waste acceptance requirements within the radioactive waste quality control system. BfS also provides criteria to enable the assessment of methods for the treatment and packaging of radioactive waste to produce waste packages suitable for disposal according to par. 74(2) Ordinance on Radiation Protection. Due to the present non-availability of a repository in Germany, quality control measures for all types of radioactive waste products are carried out prior to interim storage with respect to the future disposal. As a result BfS approves the demonstrated properties of the radioactive waste packages and confirms the fulfillment of the respective requirements. After several years of storage the properties of waste packages might have changed. By proving, that such changes have no significant impact on the quality of the waste product, the effort of requalification could be minimized. Therefore, data on the long-term behavior of radioactive waste products need to be acquired and indicators to prove the long-term stability have to be quantified. Preferably, such indicators can be determined easily with non-destructive methods, even for legacy waste packages. A promising parameter is the gas generation rate. The relationship between gas generation rate and long term stability is presented as first result of an ongoing study on behalf of BfS. Permissible gas

  9. Stress degradation studies and stability-indicating TLC-densitometric method of glycyrrhetic acid

    PubMed Central

    2013-01-01

    Background Glycyrrhetic acid, a pentacyclic triterpenoid, possesses a broad range of pharmacological activities and serves as template to synthesize many bioactive drugs. This paper describes a simple, accurate, and sensitive stability-indicating TLC densitometric method for the determination of glycyrrhetic acid and its degradation product as per the ICH guidelines. Results Separation was carried out on TLC aluminium sheet pre-coated with silica gel 60F254 using chloroform, methanol and formic acid (9:0.9:0.1, v/v). Compact spot for glycyrrhetic acid was found at Rf value of 0.42 ± 0.03. Densitometric analysis was carried out in the absorbance mode at λmax 254 nm. Glycyrrhetic acid was found to be stable to the exposure of base, neutral, oxidation, dry heating treatment and wet heating treatment, but showed degradation under acidic and photochemical conditions. Moreover, fragmentation pattern of glycyrrhetic acid was developed by using a positive ion electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QqTOF-MS/MS) hybrid instrument. A photo-degraded product was characterized through comparison of mass spectrometric studies with glycyrrhetic acid. Conclusion The developed stability-indicating TLC-densitometric method can be applied for routine analysis of glycyrrhetic acid in the presence of its degradation products. PMID:23327365

  10. A validated stability-indicating UPLC method for desloratadine and its impurities in pharmaceutical dosage forms.

    PubMed

    Rao, Dantu Durga; Satyanarayana, N V; Malleswara Reddy, A; Sait, Shakil S; Chakole, Dinesh; Mukkanti, K

    2010-02-05

    A novel stability-indicating gradient reverse phase ultra-performance liquid chromatographic (RP-UPLC) method was developed for the determination of purity of desloratadine in presence of its impurities and forced degradation products. The method was developed using Waters Aquity BEH C18 column with mobile phase containing a gradient mixture of solvents A and B. The eluted compounds were monitored at 280nm. The run time was 8min within which desloratadine and its five impurities were well separated. Desloratadine was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. Desloratadine was found to degrade significantly in oxidative and thermal stress conditions and stable in acid, base, hydrolytic and photolytic degradation conditions. The degradation products were well resolved from main peak and its impurities, thus proved the stability-indicating power of the method. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness. This method was also suitable for the assay determination of desloratadine in pharmaceutical dosage forms.

  11. Stability-Indicating HPLC Determination of Trandolapril in Bulk Drug and Pharmaceutical Dosage Forms

    PubMed Central

    Al-Hawash, Leena A.; Shakya, Ashok K.; Saleem, Maher L.

    2015-01-01

    A rapid, simple, accurate, precise, economical, robust, and stability indicating reverse phase HPLC-PDA procedure has been developed and validated for the determination of trandolapril. The trandolapril was separated isocratically on Hypersil-Gold C18 column (250 mm × 4.6 mm, 5 μm) with a mobile phase consisting of 50% acetonitrile and 50% water (containing 0.025% triethylamine, pH 3.0 ± 0.1), at 25 ± 2°C. Retention time of the drug was ~4.6 min. The eluted compounds were monitored and identified at 210 nm. The linearity of the method was excellent (r2 > 0.9999) over the concentration range of 1–24 μg/mL; the limit of detection (LOD) and limit of quantitation (LOQ) were 0.0566 μg/mL and 0.1715 μg/mL, respectively. The overall precision was less than 2%. Mean recovery of trandolapril was more than 99%; no interference was found from the component present in the preparation. Stability studies indicate that the drug was stable to sunlight and UV light. The drug gives 6 different oxidative products on exposure to hydrogen peroxide. Slight degradation was observed in acidic condition. Degradation was higher in the alkaline condition compared to other conditions. The robustness of the method was studied using factorial design experiment. PMID:25802524

  12. Stability-indicating HPTLC determination of ambroxol hydrochloride in bulk drug and pharmaceutical dosage form.

    PubMed

    Jain, P S

    2010-01-01

    A simple, selective, precise, and stability-indicating high-performance thin-layer chromatographic (HPTLC) method for the analysis of ambroxol hydrochloride both as a bulk drug and in formulations was developed and validated. The method employed HPTLC aluminium plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of methanol-triethylamine (4:6 v/v). The system was found to give a compact spot for ambroxol hydrochloride (R(f) value of 0.53 +/- 0.02). Densitometric analysis of ambroxol hydrochloride was carried out in the absorbance mode at 254 nm. The linear regression analysis data for the calibration plots showed good linear relationship with r(2) = 0.9966 +/- 0.0013 with respect to peak area in the concentration range 100-1000 ng/spot. The mean value +/- standard deviation of slope and intercept were 164.85 +/- 0.72 and 1168.3 +/- 8.26 with respect to peak area. The method was validated for precision, recovery, and robustness. The limits of detection and quantitation were 10 and 30 ng/spot, respectively. Ambroxol hydrochloride was subjected to oxidation and thermal degradation. The drug undergoes degradation under oxidation and heat conditions. This indicates that the drug is susceptible to oxidation and heat. Statistical analysis proves that the method is repeatable, selective, and accurate for the estimation of said drug. Stability indicating of new chemical entities is an important part for the drug development of ambroxol hydrochloride and for its estimation in plasma and other biological fluids; the novel Statistical analysis proves that the method is repeatable and selective for the analysis of ambroxol hydrochloride as bulk drug and in pharmaceutical formulations. The proposed developed HPTLC method can be applied for identification and quantitative determination of ambroxol hydrochloride in bulk drug and dosage forms. This work is to determine the purity of the drug available from the various sources by detecting

  13. Stress degradation studies on betahistine and development of a validated stability-indicating assay method.

    PubMed

    Khedr, Alaa; Sheha, Mahmoud

    2008-06-15

    The purpose of this work was to study the stability of betahistine (BET) at different stress conditions and to develop a sensitive stability-indicating high-performance liquid chromatographic (HPLC) assay method. The stress conditions applied were including the effect of heat, moisture, acid-base, and ultra-violet (UV) light. Betahistine and its decomposition products were derivatized by reaction with dansyl chloride (Dan-Cl) and analyzed by HPLC equipped with fluorescence detector (FL) set at 336 and 531 nm as excitation and emission wavelengths, respectively. The drug was particularly labile at UV light and oxygen rich media. Two potential degradation products could be separated and identified by spectral methods. The chromatographic method involved Zorbax Eclipse XDB-C(18) column kept at 30+/-2 degrees C and a gradient elution with mobile phase composed of acetonitrile and 0.02 mol L(-1) sodium acetate. The response factor of dansylated BET monitored by fluorescence detection was 32 times more than its UV response. The calibration curve of BET in bulk form was linear from 0.005 to 4.2 ng microL(-1). Intraday and interday precision were less than 0.04% (CV), and accuracy was between 99.2% and 100.9% over 2.0 ng microL(-1). The limit of detection was 0.002 ng microL(-1). The method was also validated for sample stability during reaction, robustness and selectivity. The method was applied for purity testing of betahistine in tablet form.

  14. Stability-indicating LC method for the estimation of bendamustine hydrochloride and its related impurities.

    PubMed

    Kasa, Srinivasulu; Raja Sekhar Reddy, M; Kadaboina, Raja Sekhar; Murki, Veerender; Mulukutla, Venkata Suryanarayana

    2014-08-01

    A novel, simple, sensitive and stability-indicating high-performance liquid chromatography method was developed and validated for the quantification of impurities (process related and degradants) and the assay determination of Bendamustine hydrochloride. A chromatographic separation of Bendamustine and its impurities was achieved with an Inertsil ODS-2 analytical column, 250 × 4.6 mm, 5 µm, using gradient elution with mobile phase A consisting of a mixture of water and trifluoroacetic acid (1000:1, v/v) and mobile phase B consisting of acetonitrile. The instrumental settings included a flow rate of 1.0 mL/min, column temperature of 27°C and a detector wavelength of 233 nm, using a photodiode array detector. The tailing factor for Bendamustine was 1.10. Bendamustine hydrochloride was exposed to thermal, photolytic, hydrolytic and oxidative stress conditions and the stressed samples were analyzed by the proposed method. Peak homogeneity data of Bendamustine were obtained by using a photodiode array detector in the stressed sample chromatograms, which demonstrated the specificity of the method for estimation in the presence of degradants. The developed method was validated for parameters such as precision, accuracy, linearity, limit of detection, limit of quantification, ruggedness and robustness. The stability tests were also performed on drug substances as per International Conference on Harmonization guidelines.

  15. Development and validation of stability-indicating HPLC method for determination of cefpirome sulfate.

    PubMed

    Zalewski, Przemysław; Skibiński, Robert; Cielecka-Piontek, Judyta; Bednarek-Rajewska, Katarzyna

    2014-01-01

    The stability-indicating LC assay method was developed and validated for quantitative determination of cefpirome sulfate (CPS) in the presence of degradation products formed during the forced degradation studies. An isocratic HPLC method was developed with Lichrospher RP-18 column, 5 μm particle size, 125 mm x 4 mm column and 12 mM ammonium acetate-acetonitrile (90 : 10 v/v) as a mobile phase. The flow rate of the mobile phase was 1.0 mL/min. Detection wavelength was 270 nm and temperature was 30 degrees C. Cefpirome sulfate as other cephalosporins was subjected to stress conditions of degradation in aqueous solutions including hydrolysis, oxidation, photolysis and thermal degradation. The developed method was validated with regard to linearity, accuracy, precision, selectivity and robustness. The method was applied successfully for identification and determination of cefpirome sulfate in pharmaceuticals and during kinetic studies.

  16. A Stability Indicating HPLC Method for the Determination of Nitisinone in Capsules

    PubMed Central

    Souri, Effat; Lahiji, Farnaz R.; Nourhashemi, Tannaz; Jalalizadeh, H.

    2015-01-01

    In this study a simple and efficient stability-indicating HPLC method with short run time was developed for the determination of nitisinone. The stress degradation of nitisinone was studied in different acidic, basic, oxidative, thermal and photolytic conditions. The chromatographic separation was achieved on a Nova-Pak C18 column using a mixture of 50 mM NaH2PO4 (pH 2.5) and acetonitrile (45:55, v/v) as mobile phase. UV detection was performed at 280 nm. Good linearity was observed over the concentration range of 0.5-50 μg/ml with r2>0.999. The within-day and between-day precision values were less than 2%. The proposed method could be used for the determination of nitisinone in the presence of its degradation products and also dosage form excipients for the quality control purposes. PMID:26180282

  17. Stability indicating HPLC method for the simultaneous determination of moxifloxacin and prednisolone in pharmaceutical formulations

    PubMed Central

    2012-01-01

    Background A simple, specific, and fast stability indicating reverse phase liquid chromatographic method was established for instantaneous determination of moxifloxacin and prednisolone in bulk drugs and pharmaceutical formulations. Results Optimum chromatographic separations among the moxifloxacin, prednisolone and stress-induced degradation products were achieved within 10 minutes by use of BDS Hypersil C8 column (250 X 4.6 mm, 5 μm) as stationary phase with mobile phase consisted of a mixture of phosphate buffer (18 mM) containing 0.1% (v/v) triethylamine, at pH 2.8 (adjusted with dilute phosphoric acid) and methanol (38:62 v/v) at a flow rate of 1.5 mL min-1. Detection was performed at 254 nm using diode array detector. The method was validated in accordance with ICH guidelines. Response was a linear function of concentrations over the range of 20–80 μg mL-1 for moxifloxacin (r2 ≥ 0.998) and 40–160 μg mL-1 for prednisolone (r2 ≥ 0.998). The method was resulted in good separation of both the analytes and degradation products with acceptable tailing and resolution. The peak purity index for both the analytes after all types of stress conditions was ≥ 0.9999 indicated a complete separation of both the analyte peaks from degradation products. The method can therefore, be regarded as stabilityindicating. Conclusions The developed method can be applied successfully for simultaneous determination of moxifloxacin and prednisolone in pharmaceutical formulations and their stability studies. PMID:22947049

  18. Validated stability-indicating TLC method for the determination of noscapine.

    PubMed

    Ashour, Ahmed; Hegazy, Maha Abdel Monem; Moustafa, Azza Aziz; Kelani, Khadiga Omar; Fattah, Laila Elsayed Abdel

    2009-07-01

    A sensitive, selective, precise and stability-indicating thin-layer chromatographic (TLC) method was developed and validated for the analysis of noscapine, both as a bulk drug and in its formulation. The method employed TLC aluminium plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of chloroform-methanol (10:0.5 v/v). Densitometric analysis of noscapine and its degradation products was carried out in the absorbance mode at 254 nm. This system was found to give compact symmetrical spots for noscapine (R(f) value 0.85 +/- 0.04). Noscapine was subjected to acid and alkali hydrolysis, oxidation and photo degradation. The drug undergoes photo degradation and also degrades under acidic and basic conditions. The prepared degradation products were identified and verified through infrared (IR) and mass spectral analyses. The degraded products were also well resolved from the pure drug with significantly different R(f) values and they were quantitatively determined. The method was validated for linearity, precision, robustness, limit of detection (LOD), limit of quantitation (LOQ), specificity and accuracy. Linearity was found to be in the 1.0-10.0 microg, 0.4-3.2 microg, 1.0-9.0 microg and 0.5-5.0 microg/band ranges for noscapine, cotarnine, meconine and opionic acid, respectively. The polynomial regression analysis for the calibration plots showed a good polynomial relationship with r(2) of 0.9998, 9989, 9996 and 0.9997 for noscapine and its three degradation products, cotarnine, meconine and opionic acid, respectively. Statistical analysis proves that the method is repeatable and specific for the estimation of noscapine. As this approach could effectively separate the drug from its degradation products it can be employed as a stability-indicating method in Quality Control laboratories.

  19. Development and validation of a stability-indicating RP-LC method for famciclovir.

    PubMed

    Raman, N V V S S; Harikrishna, K A; Prasad, A V S S; Ratnakar Reddy, K; Ramakrishna, K

    2009-12-05

    A novel stability-indicating gradient reverse phase liquid chromatographic (RP-LC) method was developed for the determination of purity of famciclovir (FCV) in presence of its impurities and degradation products. The method was developed using Inertsil ODS 3 V (250 x 4.6 mm, 5 microm) column with mobile phase containing a gradient mixture of solvent A and B. 0.01 M potassium dihydrogen orthophosphate buffer, pH adjusted to 6.0 with 1% potassium hydroxide was used as buffer. Buffer and methanol in 80:20 (v/v) ratio was used as solvent A and buffer and methanol in 20:80 (v/v) ratio was used as solvent B. The gradient program (T/%B) was set as 0/5, 15/30, 25/50, 45/60, 55/5 and 60/5. The eluted compounds were monitored at 215 nm. FCV was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. FCV was found to degrade significantly in oxidative, acid and base degradation conditions and mildly in hydrolytic degradation conditions and stable in thermal and photolytic degradation conditions. The degradation products were well resolved from main peak and its impurities thus proved the stability-indicating power of the method. The developed method was validated as per International Conference on Harmonization (ICH) guidelines with respect to specificity, limit of detection, limit of quantitation, precision, linearity, accuracy, robustness and system suitability. This method is also suitable for the assay of famciclovir which ranged from 99.9% to 100.2%.

  20. Stability-indicating HPLC Method for Simultaneous Determination of Aspirin and Prasugrel

    PubMed Central

    Patel, Shital M.; Patel, C. N.; Patel, V. B.

    2013-01-01

    A simple, sensitive, specific, accurate, and stability-indicating reversed phase high performance liquid chromatographic method was developed for the simultaneous determination of aspirin and prasugrel, using a Kromasil 100 C18 (150×4.6 mm, 5 μ) column and a mobile phase composed of acetonitrile:methanol:water (30:10:60, v/v), pH 3.0 adjusted with o-phosphoric acid. The retention times of aspirin and prasugrel were found to be 3.28 min and 6.61 min, respectively. Linearity was established for aspirin and prasugrel in the range of 15-150 and 2-20 μg/ml, respectively. The percentage recoveries of aspirin and prasugrel were found to be in the range of 99.34-100.32% and 98.92-102.09%, respectively. Both the drugs were subjected to acid, alkali and neutral hydrolysis, oxidation, dry heat, and UV degradation. The degradation studies indicated aspirin to be more susceptible to alkaline hydrolysis, while prasugrel to be more susceptible to neutral hydrolysis. The degradation products were well resolved from the pure drug with significant differences in their retention time values. This method can be successfully employed for simultaneous quantitative analysis of aspirin and prasugrel in bulk drugs and formulations. PMID:24302795

  1. Development and Validation of Stability Indicating Spectroscopic Method for Content Analysis of Ceftriaxone Sodium in Pharmaceuticals

    PubMed Central

    Ethiraj, Revathi; Thiruvengadam, Ethiraj; Sampath, Venkattapuram Saravanan; Vahid, Abdul; Raj, Jithin

    2014-01-01

    A simple, selective, and stability indicating spectroscopic method has been selected and validated for the assay of ceftriaxone sodium in the powder for injection dosage forms. Proposed method is based on the measurement of absorbance of ceftriaxone sodium in aqueous medium at 241 nm. The method obeys Beer's law in the range of 5–50 μg/mL with correlation coefficient of 0.9983. Apparent molar absorptivity and Sandell's sensitivity were found to be 2.046 × 103 L mol−1 cm−1 and 0.02732 μg/cm2/0.001 absorbance units. This study indicated that ceftriaxone sodium was degraded in acid medium and also underwent oxidative degradation. Percent relative standard deviation associated with all the validation parameters was less than 2, showing compliance with acceptance criteria of Q2 (R1), International Conference on Harmonization (2005) guidelines. Then the proposed method was successfully applied to the determination of ceftriaxone sodium in sterile preparation and results were comparable with reported methods. PMID:27355020

  2. Stability-indicating high-performance liquid chromatographic assay of busulfan in aqueous and plasma samples.

    PubMed

    Chow, D S; Bhagwatwar, H P; Phadungpojna, S; Andersson, B S

    1997-12-19

    A sensitive, specific and stability-indicating high-performance liquid chromatographic (HPLC) assay, involving pre-column derivatization and solid-phase extraction (SPE), was developed and validated for the quantitation of busulfan (BU) in aqueous and plasma samples. The linearity of the assay was in the concentration ranges of 0.15-10 microg/ml and 0.15-3 microg/ml for aqueous and plasma samples, respectively. The within-day and between-day variations were 2.90 and 3.31%, respectively, for the aqueous samples, and 9.24 and 14.56%, respectively, for the plasma samples. The overall recovery, derivatization yield and SPE efficiency of BU from plasma samples were 82.03, 108.01 and 86.69%, respectively. Forced degraded samples, either in highly acidic, neutral or basic medium, produced no interfering peaks in the chromatogram. The reported assay requires only 0.2 ml of plasma for the analysis, and its sensitivity is 150 ng/ml by monitoring samples at a wavelength of 254 nm, sufficient to study the plasma pharmacokinetics of BU in rats after a clinically relevant oral dose. Moreover, the sensitivity of the assay can be significantly increased to 30 ng/ml by monitoring samples at a wavelength of 278 nm. The applications of the assay were demonstrated with BU solubility measurements in two aqueous systems and with plasma samples from a Sprague-Dawley rat for an in vivo pharmacokinetic study. In addition, the assay has been employed in the development of a patented intravenous formulation, and in evaluations of stability, preclinical pharmacokinetics in rats and dogs, and clinical phase I trial of the formulation. The assay is readily adaptable to clinical therapeutic drug monitoring.

  3. Stability indicating LC method for simultaneous determination of irbesartan and hydrochlorothiazide in pharmaceutical preparations.

    PubMed

    Rane, V P; Patil, K R; Sangshetti, J N; Yeole, R D; Shinde, D B

    2010-08-01

    A simple and precise stability-indicating liquid chromatography method is developed and validated for the quantitative simultaneous estimation of irbesartan (IRB) and hydrochlorothiazide (HCTZ) in combined pharmaceutical dosage form. A chromatographic separation of the two drugs was achieved with an Ace5 C(18) 25-cm analytical column using buffer-acetonitrile (70:30 v/v). The buffer used in mobile phase contains 50 mM ammonium acetate pH adjusted 5.5 with acetic acid. The instrumental settings are flow rate of 1.5 mL/min, column temperature at 30 degrees C, and detector wavelength of 235 nm using a photodiode array detector. IRB, HCTZ, and their combination drug products were exposed to thermal, photolytic, hydrolytic, and oxidative stress conditions, and the stressed samples were analyzed by the proposed method. Peak homogeneity data of IRB and HCTZ is obtained using photodiode array detector. In the stressed sample chromatograms, it demonstrated the specificity of the assay method for their estimation in presence of degradation products. The described method shows excellent linearity over a range of 10-200 microg/mL for IRB and 5-100 microg/mL for HCTZ. Methylparaben was used as internal standard. The correlation coefficient for IRB and HCTZ are 0.998 and 0.999. The mean recovery values for IRB and HCTZ ranged from 100.45% to 101.25%. The limit of detection for IRB and HCTZ were 0.019 and 0.023 microg/mL, respectively, and the limit of quantification were 0.053 and 0.070 microg/mL, respectively. The proposed method was suitable for quantitative determination and stability study of IRB and HCTZ in pharmaceutical preparations and also can be used in the quality control of bulk manufacturing and pharmaceutical dosage forms.

  4. [Determination and stability tests of triclosan in disinfectants].

    PubMed

    Li, Jie; Zhao, Hai-yan; Peng, Guo-ke; Tian, Pei-yao; Li, Chang-qing

    2002-07-01

    A method has been developed for the determination of triclosan in antibacterial detergent by RP-HPLC equipped with a diode-array detector. A Kromasil C18 column (200 mm x 4.6 mm i.d., 7 microns) was used with a mobile phase of methanol-acetonitrile-water (40:40:20, volume ratio) containing 0.02 mol/L KH2PO4 at pH 2.7 and UV detection at 280 nm. The samples were dissolved with the mobile phase by ultrasonic method. The recoveries of triclosan were from 94.2% to 102.2% and the RSDs were from 2.2% to 3.0%. The method is simple, rapid, accurate and reproducible. The concentrations of standards and samples did not change evidently after storage at 54 degrees C for 14 d and at 37 degrees C for 90 d. The results showed that triclosan has a good stability.

  5. A stability-indicating HPLC method for simultaneous determination of morphine and naltrexone.

    PubMed

    Jafari-Nodoushan, Milad; Barzin, Jalal; Mobedi, Hamid

    2016-02-01

    This study developed a stability-indicating reversed-phase HPLC method for the simultaneous determination of morphine sulfate and naltrexone hydrochloride content in bulk, Solid dosage forms and in-vitro dissolution samples to support product development and quality control efforts. Chromatographic separation of the pharmaceutical compound was achieved on a perfectSil™ MZ C18 column (250×4.6mm, 5μm) with an isocratic mobile phase composed of a mixture of acetate buffer (10mM, pH 4, containing 0.1% of 1-heptanesulfonic acid sodium salt) and acetonitrile with 80/20 at a flow rate of 1.5mlmin(-1). Both analytes were quantified using a photodiode array detector set at a wavelength of 280nm and column temperature was set to 30°C. naltrexone, morphine and a mixture of the two were subjected to thermal, peroxide, acid, base and photolytic degradation and their peak homogeneity was obtained using a photodiode array detector, demonstrating the specificity of method. These pharmaceuticals were spiked in biological fluid to examine method selectivity. The method was validated for system suitability, linearity, accuracy, precision, detection and quantification limits and robustness and was found it is acceptable in range of 2-250μgml(-1) for morphine and 4-100μgml(-1) for naltrexone.

  6. Smart stability-indicating spectrophotometric methods for determination of binary mixtures without prior separation.

    PubMed

    El-Bardicy, Mohammad G; Lotfy, Hayam M; El-Sayed, Mohammad A; El-Tarras, Mohammad F

    2008-01-01

    Ratio subtraction and isosbestic point methods are 2 innovating spectrophotometric methods used to determine vincamine in the presence of its acid degradation product and a mixture of cinnarizine (CN) and nicergoline (NIC). Linear correlations were obtained in the concentration range from 8-40 microg/mL for vincamine (I), 6-22 microg/mL for CN (II), and 6-36 microg/mL for NIC (III), with mean accuracies 99.72 +/- 0.917% for I, 99.91 +/- 0.703% for II, and 99.58 +/- 0.847 and 99.83 +/- 1.039% for III. The ratio subtraction method was utilized for the analysis of laboratory-prepared mixtures containing different ratios of vincamine and its degradation product, and it was valid in the presence of up to 80% degradation product. CN and NIC in synthetic mixtures were analyzed by the 2 proposed methods with the total content of the mixture determined at their respective isosbestic points of 270.2 and 235.8 nm, and the content of CN was determined by the ratio subtraction method. The proposed method was validated and found to be suitable as a stability-indicating assay method for vincamine in pharmaceutical formulations. The standard addition technique was applied to validate the results and to ensure the specificity of the proposed methods.

  7. Spectrofluorimetric methods of stability-indicating assay of certain drugs affecting the cardiovascular system

    NASA Astrophysics Data System (ADS)

    Moussa, B. A.; Mohamed, M. F.; Youssef, N. F.

    2011-01-01

    Two stability-indicating spectrofluorimetric methods have been developed for the determination of ezetimibe and olmesartan medoxomil, drugs affecting the cardiovascular system, and validated in the presence of their degradation products. The first method, for ezetimibe, is based on an oxidative coupling reaction of ezetimibe with 3-methylbenzothiazolin-2-one hydrazone hydrochloride in the presence of cerium (IV) ammonium sulfate in an acidic medium. The quenching effect of ezetimibe on the fluorescence of excess cerous ions is measured at the emission wavelength, λem, of 345 nm with the excitation wavelength, λex, of 296 nm. Factors affecting the reaction were carefully studied and optimized. The second method, for olmesartan medoxomil, is based on measuring the native fluorescence intensity of olmesartan medoxomil in methanol at λem = 360 nm with λex = 286 nm. Regression plots revealed good linear relationships in the assay limits of 10-120 and 8-112 g/ml for ezetimibe and olmesartan medoxomil, respectively. The validity of the methods was assessed according to the United States Pharmacopeya guidelines. Statistical analysis of the results exposed good Student's t-test and F-ratio values. The introduced methods were successfully applied to the analysis of ezetimibe and olmesartan medoxomil in drug substances and drug products as well as in the presence of their degradation products.

  8. Stability-indicating HPLC Method for Simultaneous Determination of Montelukast and Fexofenadine Hydrochloride

    PubMed Central

    Pankhaniya, Mona; Patel, Parula; Shah, J. S.

    2013-01-01

    A simple, specific, accurate, and stability-indicating reversed-phase high-performance liquid chromatographic method was developed for the simultaneous determination of montelukast and fexofenadine hydrochloride, using a Lichrospher® 100, RP-18e column and a mobile phase composed of methanol:0.1% o-phosphoric acid (90:10 v/v), pH 6.8. The retention times of montelukast and fexofenadine hydrochloride were found to be 10.16 and 12.03 min, respectively. Linearity was established for montelukast and fexofenadine hydrochloride in the range of 2-10 μg/ml and 24-120 μg/ml, respectively. The percentage recoveries of montelukast and fexofenadine hydrochloride were found to be in the range of 99.09 and 99.81%, respectively. Both the drugs were subjected to acid and base hydrolysis, oxidation, photolytic, and thermal degradation conditions. The degradation products of montelukast and fexofenadine hydrochloride were well resolved from the pure drug with significant differences in their retention time values. This method can be successfully employed for simultaneous quantitative analysis of montelukast and fexofenadine hydrochloride in bulk drugs and formulations. PMID:24082344

  9. Stability Indicating LC-Method for Estimation of Paracetamol and Lornoxicam in Combined Dosage Form

    PubMed Central

    Shah, Dimal A.; Patel, Neel J.; Baldania, Sunil L.; Chhalotiya, Usman K.; Bhatt, Kashyap K.

    2011-01-01

    A simple, specific and stability indicating reversed phase high performance liquid chromatographic method was developed for the simultaneous determination of paracetamol and lornoxicam in tablet dosage form. A Brownlee C-18, 5 μm column having 250×4.6 mm i.d. in isocratic mode, with mobile phase containing 0.05 M potassium dihydrogen phosphate:methanol (40:60, v/v) was used. The flow rate was 1.0 ml/min and effluents were monitored at 266 nm. The retention times of paracetamol and lornoxicam were 2.7 min and 5.1 min, respectively. The linearity for paracetamol and lornoxicam were in the range of 5–200 μg/ml and 0.08–20 μg/ml, respectively. Paracetamol and lornoxicam stock solutions were subjected to acid and alkali hydrolysis, chemical oxidation and dry heat degradation. The proposed method was validated and successfully applied to the estimation of paracetamol and lornoxicam in combined tablet dosage form. PMID:21617776

  10. Spatial scale of similarity as an indicator of metacommunity stability in exploited marine systems.

    PubMed

    Shackell, Nancy L; Fisher, Jonathan A D; Frank, Kenneth T; Lawton, Peter

    2012-01-01

    The spatial scale of similarity among fish communities is characteristically large in temperate marine systems: connectivity is enhanced by high rates of dispersal during the larval/juvenile stages and the increased mobility of large-bodied fish. A larger spatial scale of similarity (low beta diversity) is advantageous in heavily exploited systems because locally depleted populations are more likely to be "rescued" by neighboring areas. We explored whether the spatial scale of similarity changed from 1970 to 2006 due to overfishing of dominant, large-bodied groundfish across a 300 000-km2 region of the Northwest Atlantic. Annually, similarities among communities decayed slowly with increasing geographic distance in this open system, but through time the decorrelation distance declined by 33%, concomitant with widespread reductions in biomass, body size, and community evenness. The decline in connectivity stemmed from an erosion of community similarity among local subregions separated by distances as small as 100 km. Larger fish, of the same species, contribute proportionally more viable offspring, so observed body size reductions will have affected maternal output. The cumulative effect of nonlinear maternal influences on egg/larval quality may have compromised the spatial scale of effective larval dispersal, which may account for the delayed recovery of certain member species. Our study adds strong support for using the spatial scale of similarity as an indicator of metacommunity stability both to understand the spatial impacts of exploitation and to refine how spatial structure is used in management plans.

  11. Validation of a Stability-Indicating Method for Methylseleno-l-Cysteine (l-SeMC)

    PubMed Central

    Canady, Kristin; Cobb, Johnathan; Deardorff, Peter; Larson, Jami; White, Jonathan M.; Boring, Dan

    2016-01-01

    Methylseleno-l-cysteine (l-SeMC) is a naturally occurring amino acid analogue used as a general dietary supplement and is being explored as a chemopreventive agent. As a known dietary supplement, l-SeMC is not regulated as a pharmaceutical and there is a paucity of analytical methods available. To address the lack of methodology, a stability-indicating method was developed and validated to evaluate l-SeMC as both the bulk drug and formulated drug product (400 µg Se/capsule). The analytical approach presented is a simple, nonderivatization method that utilizes HPLC with ultraviolet detection at 220 nm. A C18 column with a volatile ion-pair agent and methanol mobile phase was used for the separation. The method accuracy was 99–100% from 0.05 to 0.15 mg/mL l-SeMC for the bulk drug, and 98–99% from 0.075 to 0.15 mg/mL l-SeMC for the drug product. Method precision was <1% for the bulk drug and was 3% for the drug product. The LOQ was 0.1 µg/mL l-SeMC or 0.002 µg l-SeMC on column. PMID:26199341

  12. Degradation Pathway for Eplerenone by Validated Stability Indicating UP-LC Method.

    PubMed

    Sudhakar Babu, Kondru; Madireddy, Venkataramanna; Indukuri, Venkata Somaraju

    2012-01-01

    Degradation pathway for eplerenone is established as per ICH recommendations by validated and stability-indicating reverse phase liquid chromatographic method. Eplerenone is subjected to stress conditions of acid, base, oxidation, and thermal and photolysis. Significant degradation is observed in acid and base stress conditions. Four impurities are studied and the major degradant (RRT about 0.31) was identified by LC-MS and spectral analysis. The stress samples are assayed against a qualified reference standard and the mass balance is found close to 99.5%. Efficient chromatographic separation is achieved on a Waters symmetry C18 stationary phase with simple mobile phase combination delivered in gradient mode and quantification is carried at 240 nm at a flow rate of 1.0 mL min(-1). In the developed LC method the resolution between eplerenone and four potential impurities (imp-1, imp-2, imp-3, and imp-4) is found to be greater than 4.0. Regression analysis shows an r value (correlation coefficient) of greater than 0.999 for eplerenone and four potential impurities. This method is capable to detect the impurities of eplerenone at a level of 0.020% with respect to test concentration of 1.0 mg mL(-1) for a 20 μL injection volume. The developed UPLC method is validated with respect to specificity, linearity and range, accuracy, precision, and robustness for impurities and assay determination.

  13. A Stability Indicating HPLC Method for the Determination of Fluvoxamine in Pharmaceutical Dosage Forms

    PubMed Central

    Souri, Effat; Donyayi, Hassan; khaniha, Reza Ahmad; Barazandeh Tehrani, Maliheh

    2015-01-01

    Fluvoxamine maleate is a selective serotonin reuptake inhibitor, which is used for the treatment of different types of depressive disorders. In the present study, a stability indicating HPLC method was developed and validated for the determination of fluvoxamine maleate. The chromatographic separation was carried out using a Nova-Pak CN column and a mixture of K2HPO4 50 mM (pH 7.0) and acetonitrile (60: 40, v/v) as the mobile phase. Target compounds were detected using a UV detector set at 235 nm. The developed method was linear over the concentration range of 1-80 μg/ml with acceptable precision (CV values < 2.0%) and accuracy (error values < 1.6%). The degradation studies showed that fluvoxamine maleate is relatively unstable under acidic, basic and oxidative conditions and also when exposed to UV radiation. On the other hand, the bulk powder of fluvoxamine maleate was relatively stable when exposed to visible light or heat. The proposed method was successfully applied for the determination of active ingredient of fluvoxamine dosage form without any interference from tablet excipients. PMID:26664372

  14. Stability-Indicating HPTLC Determination of Imatinib Mesylate in Bulk Drug and Pharmaceutical Dosage

    NASA Astrophysics Data System (ADS)

    Musmade, P.; Vadera, N.; Subramanian, G.

    A simple, selective, precise and stability-indicating high-performance thin-layer chromatographic method of analysis of imatinib mesylate both as a bulk drug and in formulations was developed and validated. The method employed HPTLC aluminum plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of chloroform:methanol (6:4, v/v). The system was found to give compact spot for imatinib mesylate (R f value of 0.53 ± 0.02). Densitometric analysis of imatinib mesylate was carried out in the absorbance mode at 276 nm. The linear regression analysis data for the calibration plots showed good linear relationship with r 2 = 0.9966 ± 0.0013 with respect to peak area in the concentration range 100-1,000 ng per spot. The mean value ± SD of slope and intercept were 164.85 ± 0.72 and 1168.3 ± 8.26, respectively, with respect to peak area. The method was validated for precision, recovery, and robustness. The limits of detection and quantitation were 10 and 30 ng per spot, respectively. Imatinib mesylate was subjected to acid and alkali hydrolysis, and oxidation and thermal degradation. The drug undergoes degradation under acidic, basic, oxidation, and heat conditions. This indicates that the drug is susceptible to acid, base hydrolysis, oxidation, and heat. Statistical analysis proves that the method is repeatable, selective, and accurate for the estimation of the said drug. The proposed developed HPTLC method can be applied for identification and quantitative determination of imatinib mesylate in bulk drug and dosage forms.

  15. Stability indicating MEKC method for the determination of gliclazide and its specified impurities.

    PubMed

    Doomkaew, Athiporn; Prutthiwanasan, Brompoj; Suntornsuk, Leena

    2015-01-01

    A stability indicating-micellar electrokinetic chromatography method was developed and validated for the determination of gliclazide (GCZ) and its specified impurities, gliclazide impurities B (GZB) and F (GZF) in bulk and tablets. The analytes were well separated (Rs>2.1) in 5 min using 10mM phosphate buffer (pH 7.0) containing 15 mM sodium dodecyl sulfate on a fused-silica capillary with an effective length of 40 cm and an inner diameter of 50 μm, injection at 50 mbar for 5s, temperature of 25°C, applied voltage of 20 kV and photodiode array detection at 225 nm. The method showed good linearity (r(2)>0.99, in the ranges of 128-192, 20-60 and 10-50 μg/mL for GCZ, GZB and GZF, respectively) and precision (%RSD for intra- and inter-day precision of less than 2.00%, n=3) for all compounds. Accuracy represented as %recovery was between 99.1 and 100.1% with %RSDs of less than 0.59% (n=3). Limits of detection and quantitation were less than 40 and 120 μg/mL, respectively. The method was robust with %RSDs of migration time and peak areas of less than 1.36% (n=9), when buffer and separating voltage were altered around the optimal values. Stress tests showed that GCZ was stable in alkaline hydrolysis both at room and elevated temperature. However, GCZ degraded under acid and neutral hydrolysis and oxidation condition. Elevated temperature and exposure to sunlight accelerated GCZ degradation and formation of GZB and an unknown degradation product. Stability profiles and degradation kinetics of GCZ could be established using the MEKC method. In addition, the method could be used for assay of GCZ in raw material and commercial tablets and results revealed that contents of GCZ in all samples were within the pharmacopeia limit. No degradation products, especially GZB and GZF, were observed in the investigated samples.

  16. Stability-indicating HPLC Method for Simultaneous Determination of Terbutaline Sulphate, Bromhexine Hydrochloride and Guaifenesin

    PubMed Central

    Porel, A.; Haty, Sanjukta; Kundu, A.

    2011-01-01

    The aim of the present study was the development and subsequent validation of a simple, precise and stability-indicating reversed phase HPLC method for the simultaneous determination of guaifenesin, terbutaline sulphate and bromhexine hydrochloride in the presence of their potential impurities in a single run. The photolytic as well as hydrolytic impurities were detected as 3,5-dihydroxybenzoic acid, 3,5-dihydroxybenzaldehyde, 1-(3,5-dihydroxyphenyl)-2-[(1,1-dimethylethyl) amino]-ethanone from terbutaline, 2-methoxyphenol and an unknown impurity identified as (2RS)-3-(2-hydroxyphenoxy)-propane-1,2-diol from guaifenesin. The chromatographic separation of all the three active components and their impurities was achieved on Wakosil II column, using phosphate buffer (pH 3.0) and acetonitrile as mobile phase which was delivered initially in the ratio of 80:20 (v/v) for 18 min, then changed to 60:40 (v/v) for next 12 min, and finally equilibrated back to 80:20 (v/v) for 10 min. Other HPLC parameters were: Flow rate at 1.0 ml/min, detection wavelengths 248 and 280 nm, injection volume 10 μl. The calibration graphs plotted with five concentrations of each component were linear with a regression coefficient R2 >0.9999. The limit of detection and limit of quantitation were estimated for all the five impurities. The established method was then validated for linearity, precision, accuracy, and specificity and demonstrated to be applicable to the determination of the active ingredients in commercial and model cough syrup. No interference from the formulation excipients was observed. These results suggest that this LC method can be used for the determination of multiple active ingredients and their impurities in a cough and cold syrup. PMID:22131621

  17. Stability-indicating HPLC Method for Simultaneous Determination of Terbutaline Sulphate, Bromhexine Hydrochloride and Guaifenesin.

    PubMed

    Porel, A; Haty, Sanjukta; Kundu, A

    2011-01-01

    The aim of the present study was the development and subsequent validation of a simple, precise and stability-indicating reversed phase HPLC method for the simultaneous determination of guaifenesin, terbutaline sulphate and bromhexine hydrochloride in the presence of their potential impurities in a single run. The photolytic as well as hydrolytic impurities were detected as 3,5-dihydroxybenzoic acid, 3,5-dihydroxybenzaldehyde, 1-(3,5-dihydroxyphenyl)-2-[(1,1-dimethylethyl) amino]-ethanone from terbutaline, 2-methoxyphenol and an unknown impurity identified as (2RS)-3-(2-hydroxyphenoxy)-propane-1,2-diol from guaifenesin. The chromatographic separation of all the three active components and their impurities was achieved on Wakosil II column, using phosphate buffer (pH 3.0) and acetonitrile as mobile phase which was delivered initially in the ratio of 80:20 (v/v) for 18 min, then changed to 60:40 (v/v) for next 12 min, and finally equilibrated back to 80:20 (v/v) for 10 min. Other HPLC parameters were: Flow rate at 1.0 ml/min, detection wavelengths 248 and 280 nm, injection volume 10 μl. The calibration graphs plotted with five concentrations of each component were linear with a regression coefficient R(2) >0.9999. The limit of detection and limit of quantitation were estimated for all the five impurities. The established method was then validated for linearity, precision, accuracy, and specificity and demonstrated to be applicable to the determination of the active ingredients in commercial and model cough syrup. No interference from the formulation excipients was observed. These results suggest that this LC method can be used for the determination of multiple active ingredients and their impurities in a cough and cold syrup.

  18. Reduction of indicator and pathogenic microorganisms in pig manure through fly ash and lime addition during alkaline stabilization.

    PubMed

    Wong, Jonathan W C; Selvam, Ammaiyappan

    2009-09-30

    A pilot scale study was conducted to evaluate the effect of lime and alkaline coal fly ash (CFA) on the reduction of pathogens in pig manure during alkaline stabilization and suppression of re-growth during post-stabilization incubation. Pig manure was mixed with CFA at 25%, 33% and 50%, and a control without fly ash was maintained. To these manure-ash mixtures, lime was added at the rate of 2% or 4% and incubated for 8 days. During the incubation, the population of Salmonella, fecal coliforms, Escherichia coli, fecal Streptococcus and total bacteria were enumerated. After the alkaline stabilization process, the mixtures were incubated under green house condition to evaluate the re-growth of pathogens. During the 8-day alkaline stabilization, Salmonella, fecal coliforms, E. coli and fecal Streptococcus were completely devitalized in manure-ash-lime mixtures, whereas in the control, incubation reduced the pathogen and total bacterial population by 2-3 logs. Fecal streptococcus was destructed within 4 days of alkaline stabilization, whereas other pathogens needed 8 days for their destruction. During the incubation in green house, an increase in the population of the pathogens and total bacteria was observed. Results indicate that alkaline stabilization of pig manure with lime at 4% and CFA at 50% is effective in devitalizing the pathogens and reducing the post-stabilization re-growth.

  19. A stability-indicating reversed-phase high-performance liquid chromatography method for Ambrisentan: an endothelin receptor antagonist.

    PubMed

    Satheeshkumar, Nanjappan; Naveenkumar, Gandham

    2014-09-01

    A stability-indicating reversed-phase high-performance liquid chromatography (HPLC) method was developed for the determination of ambrisentan, a drug used in the treatment of pulmonary hypertension. The desired chromatographic separation was achieved on a Kromasil C18 column (250 × 4.6 mm, 5 µm) using the mobile phase acetonitrile-ammonium formate (pH 3.0; 0.02 M) in gradient mode. The flow rate was set at 1.0 mL/min, and chromatograms were extracted at 262 nm using a photodiode array detector. The method was successfully validated in accordance to International Conference on Harmonization (ICH) guidelines acceptance criteria for linearity, accuracy, precision, robustness and forced degradation studies, which further proved the stability-indicating power. Linearity of ambrisentan peak area responses was demonstrated within the concentration range of 25-200 µg/mL. The limits of detection and quantitation were 0.2 and 0.6 µg/mL, respectively. Forced degradation studies were performed on ambrisentan bulk drug samples as per ICH guidelines to demonstrate the stability-indicating power of the HPLC method. Significant degradation was observed during acidic hydrolysis, neutral hydrolysis and oxidative stress. The degradation products were well resolved from primary peak of ambrisentan, indicating that the method is specific and stability indicating. The newly developed method is applicable for assay determination of active pharmaceutical ingredient.

  20. Testing of conductivity/calcium and rubidium/strontium ratios as indicators of the chemical stability of a river: comparison with a biological indicator.

    PubMed

    Nirel, P M V; Lazzarotto, J

    2005-01-01

    It is customary to detect pollution in a water flow by monitoring the increase of sensitive elements concentrations (NH4+, PO4(3-), NO3-...). However, concentrations are dependent on the flow rate and these compounds are not conservative, implying a concentration decrease downstream leading to false negative diagnosis of pollution impact. The use of elemental ratios of conservative compounds should diminish these pitfalls. We then thought of the chi/Ca (conductivity/calcium) and Rb/Sr (rubidium/strontium) ratios as water chemical stability indicators to clearly identify and discriminate point from diffuse pollutions. This hypothesis has been tested on 12 brooks located in the basin of Lake Geneva, during 2 hydrological years. The results were compared to the observed land use of the watershed and a biological indicator: the Pollution Sensitivity Index (PSI). The PSI is calculated from diatom taxonomy and evaluates biological quality with a grade ranging from 0 to 20 (bad to excellent). The main results of the research can be summarized as follows. The pollution signal is observable far downstream of the pollution site. Both chi/Ca and Rb/Sr ratios are water quality indicators expressing the stability of water chemistry. They can both be used to detect diffuse and point pollution impact. These indicators provide complementary information: chi/Ca variations increase in case of point pollution; Rb/Sr variations increase when diffuse pollutions occur. The results obtained with the indicators chi/Ca and Rb/Sr agree with biological indicator and observation of the land use. chi/Ca and Rb/Sr ratios represent important tools to identify and discriminate point source pollution from diffuse pollution.

  1. Using thermal and spectroscopic (XANES) indices to understand the biological stability of soil organic matter.

    NASA Astrophysics Data System (ADS)

    Gillespie, A. W.; Sanei, H.; Diochon, A.; Tarnocai, C.; Janzen, H.; Regier, T. Z.; Gregorich, E.

    2014-12-01

    Soil organic matter (SOM) composition is a key property that underpins ecosystem productivity. Understanding its physical, chemical and biological properties is important for evaluating its role in carbon (C) and nutrient cycling in terrestrial ecosystems. In particular, the stability of SOM (i.e., resistance to microbial degradation) has important implications in ecosystem processes, including nutrient cycling, emission of greenhouse gases from soil, and C sequestration. Thus there is interest in developing new ways to measure and quantify the labile and stable forms of soil organic carbon. In this presentation, we describe the combined use of thermal decomposition methods based on pyrolysis, and chemical properties using X-ray absorption spectroscopy (XAS), to describe the stability of soil organic matter. Soils (n=81) for this study were obtained from a wide geographical range and management practices. Controlled respiration studies were conducted on the soils to determine the biodegradability of organic C after 98 days. In the thermal analysis, the sample is subjected to a temperature ramp and pyrolyzed/volatilized organic C was recorded as a function of temperature. Analysis by XAS provided information on the types of C functional groups present in a soil sample. We show that biological stability is well described using a two component model which included thermal stability and C composition chemistry.

  2. Stability and maturity of biowaste composts derived by small municipalities: Correlation among physical, chemical and biological indices.

    PubMed

    Oviedo-Ocaña, E R; Torres-Lozada, P; Marmolejo-Rebellon, L F; Hoyos, L V; Gonzales, S; Barrena, R; Komilis, D; Sanchez, A

    2015-10-01

    Stability and maturity are important criteria to guarantee the quality of a compost that is applied to agriculture or used as amendment in degraded soils. Although different techniques exist to evaluate stability and maturity, the application of laboratory tests in municipalities in developing countries can be limited due to cost and application complexities. In the composting facilities of such places, some classical low cost on-site tests to monitor the composting process are usually implemented; however, such tests do not necessarily clearly identify conditions of stability and maturity. In this article, we have applied and compared results of stability and maturity tests that can be easily employed on site (i.e. temperature, pH, moisture, electrical conductivity [EC], odor and color), and of tests that require more complex laboratory techniques (volatile solids, C/N ratio, self-heating, respirometric index, germination index [GI]). The evaluation of the above was performed in the field scale using 2 piles of biowaste applied compost. The monitoring period was from day 70 to day 190 of the process. Results showed that the low-cost tests traditionally employed to monitor the composting process on-site, such as temperature, color and moisture, do not provide consistent determinations with the more complex laboratory tests used to assess stability (e.g. respiration index, self-heating, volatile solids). In the case of maturity tests (GI, pH, EC), both the on-site tests (pH, EC) and the laboratory test (GI) provided consistent results. Although, stability was indicated for most of the samples, the maturity tests indicated that products were consistently immature. Thus, a stable product is not necessarily mature. Conclusively, the decision on the quality of the compost in the installations located in developing countries requires the simultaneous use of a combination of tests that are performed both in the laboratory and on-site.

  3. Figure-ground processing during fixational saccades in V1: indication for higher-order stability.

    PubMed

    Gilad, Ariel; Pesoa, Yair; Ayzenshtat, Inbal; Slovin, Hamutal

    2014-02-26

    In a typical visual scene we continuously perceive a "figure" that is segregated from the surrounding "background" despite ongoing microsaccades and small saccades that are performed when attempting fixation (fixational saccades [FSs]). Previously reported neuronal correlates of figure-ground (FG) segregation in the primary visual cortex (V1) showed enhanced activity in the "figure" along with suppressed activity in the noisy "background." However, it is unknown how this FG modulation in V1 is affected by FSs. To investigate this question, we trained two monkeys to detect a contour embedded in a noisy background while simultaneously imaging V1 using voltage-sensitive dyes. During stimulus presentation, the monkeys typically performed 1-3 FSs, which displaced the contour over the retina. Using eye position and a 2D analytical model to map the stimulus onto V1, we were able to compute FG modulation before and after each FS. On the spatial cortical scale, we found that, after each FS, FG modulation follows the stimulus retinal displacement and "hops" within the V1 retinotopic map, suggesting visual instability. On the temporal scale, FG modulation is initiated in the new retinotopic position before it disappeared from the old retinotopic position. Moreover, the FG modulation developed faster after an FS, compared with after stimulus onset, which may contribute to visual stability of FG segregation, along the timeline of stimulus presentation. Therefore, despite spatial discontinuity of FG modulation in V1, the higher-order stability of FG modulation along time may enable our stable and continuous perception.

  4. Absence of kinetic thermal stabilization in a hyperthermophile rubredoxin indicated by 40 microsecond folding in the presence of irreversible denaturation.

    PubMed

    LeMaster, David M; Tang, Jianzhong; Hernández, Griselda

    2004-10-01

    The striking kinetic stability of many proteins derived from hyperthermophilic organisms has led to the proposal that such stability may result from a heightened activation barrier for unfolding independent of a corresponding increase in the thermodynamic stability. This in turn implies a corresponding retardation of the folding reaction. A commonly cited model for kinetic thermal stabilization is the rubredoxin from Pyrococcus furiosus (Pf), which exhibits an irreversible denaturation lifetime at 100 degrees C of nearly a week. Utilizing protein resonances shifted well outside of the random coil chemical shift envelope, nuclear magnetic resonance (NMR) chemical exchange measurements on Pf rubredoxin as well as on the mesophile Clostridium pasteurianum (Cp) rubredoxin demonstrate reversible thermal transition temperatures of 144 degrees C (137 degrees C for the N-terminal modified A2K variant) and 104 degrees C, respectively, with similar (un)folding rates of approximately 25,000 s(-1), only modestly slower than the diffusion controlled rate. The absence of a substantial activation barrier to rubredoxin folding as well as the similar folding kinetics of the mesophile protein indicate that kinetic stabilization has not been utilized by the hyperthermophile rubredoxin in achieving its extreme thermal stability. The two-state folding kinetics observed for Pf rubredoxin contradict a previous assertion of multiphasic folding based on hydrogen exchange data extrapolated to an estimated midpoint of transition temperature (T(m)) of nearly 200 degrees C. This discrepancy is resolved by the observation that the base-catalyzed hydrogen exchange of the model dipeptide (N-acetyl-L-cysteine-N-methylamide)4-Cd2+ is 23-fold slower than that of the free cysteine model dipeptide used to normalize the Pf rubredoxin hydrogen exchange data.

  5. The Stability of School Effectiveness Indices across Grade Levels and Subject Areas.

    ERIC Educational Resources Information Center

    Mandeville, Garrett K.; Anderson, Lorin W.

    1987-01-01

    School effectiveness indices based on regressing achievement test scores onto earlier scores and a socioeconomic status measure were obtained for South Carolina students in grades one to four. Results were unstable across grades, and grade-to-grade correlations were more significant for mathematics achievement than for reading. (Author/GDC)

  6. Stability Indicating Determination of Human Growth Hormone by Novel SE-LC Method.

    PubMed

    Rezk, Mamdouh R; Shehata, Mostafa A; Mohamed, Marwa F; Fathalla, Faten Abdel Aziz

    2016-09-01

    A selective, rapid size-exclusion chromatographic method was developed and validated for the separation of the human growth hormone (hGH) somatropin from its high-molecular-weight aggregates. Separation was achieved using a nontoxic mobile phase compared with the official method of the European Pharmacopoeia that uses 2-propanol in a mobile phase. The developed method used a YMC-Pack Diol (YMC Karasuma, Kyoto, Japan; 300 × 8.0 mm, 5 μm) analytical column. The mobile phase was formed with a pH 7phosphate buffer that was pumped at a flow rate of 1 mL/min with UV detection at 214 nm. The overall run time was 20 min and the average retention times were found to be 10.21 min for the monomer peak, 9.52 min for the dimer peak, and 9.14 min for the higher aggregate. This method was validated in terms of selectivity, linearity, and intra- and interday variations according to the International Conference on Harmonization guidelines. The developed method was applied as a rapid tool for evaluating the stability of stressed samples of hGH subjected to different temperature, agitation, and repeated freeze-thaw cycles. The developed method was successfully applied for the assessment of the quality and quantity of hGH during downstream processing, formulation, and storage.

  7. Stability indicating HPLC method for the estimation of oxycodone and lidocaine in rectal gel.

    PubMed

    Gebauer, M G; McClure, A F; Vlahakis, T L

    2001-07-31

    An HPLC method for the quantification of oxycodone and lidocaine in a gel matrix is described. The mobile phase consisted of methanol--water--acetic acid (35:15:1 v/v/v) and was delivered at 1.5 ml/min through a 4.6 x 250 mm Zorbax SB-C8 column. Oxycodone was detected at 285 nm and lidocaine at 264 nm. Linear calibration curves were obtained for oxycodone in the range of 0.05--1.5% (w/w) and for lidocaine in the range of 0.1--5.0% (w/w). Oxycodone and lidocaine were treated with hydrogen peroxide and the oxidation products were readily separated on the column. The method was applied to assess the stability of a gel containing oxycodone hydrochloride (0.3% w/w) and lidocaine (1.5% w/w). The gel was stored under refrigeration in ready-to-use syringes and under these conditions oxycodone and lidocaine were stable for at least 1 year. The gel is useful in the management of tenesmus in rectal cancer.

  8. Stability-Indicating LC Method for the Determination of Prasugrel Hydrochloride in Pharmaceutical Dosage Form.

    PubMed

    Ahirrao, Vinod K; Patil, Chabutai S; Bembalkar, Saroj B; Ubale, Sanjay B; Marathe, Rajendra P; Nawale, Rajesh B; Landge, Mahadev G; Pawar, Rajendra P

    2012-01-01

    A simple, rapid and precise method was developed for the quantitative estimation of prasugrel hydrochloride in pharmaceutical dosage form. A chromatographic separation of prasugrel and its degradants was achieved with Zorbax XDB C(8), 150 × 4.6 mm, 3.5μm analytical column using aqueous solution of 0.05 M ammonium acetate pH 4.5 with acetic acid-acetonitrile (40:60 v/v). The instrumental settings include flow rate of 1.0 ml/min, column temperature at 30°C and detector wavelength of 254 nm using a photodiode array detector. Theoretical plates for prasugrel were 7023. Tailing factor for prasugrel was 1.11. Prasugrel was exposed to thermal, photolytic, hydrolytic and oxidative stress conditions, and the stressed samples were analyzed by the proposed method. Peak homogeneity data of prasugrel was obtained using photodiode array detector in the stressed sample chromatograms, which demonstrated the specificity of the method for the estimation in presence of degradants. The described method showed excellent linearity over a range of 10-300 μg/ml for prasugrel. The correlation coefficient is 0.999. The relative standard deviation of peak area for six measurements is always less than 2%. Overall, the proposed method was found to be suitable and accurate for quantitative determination and stability study of prasugrel in pharmaceutical dosage form.

  9. Removal of bacterial and viral faecal indicator organisms in a waste stabilization pond system in Choconta, Cundinamarca (Colombia).

    PubMed

    Campos, C; Guerrero, A; Cárdenas, M

    2002-01-01

    A major objective for domestic wastewater treatment using waste stabilization pond systems is the removal of pathogenic microorganisms. Traditional evaluation parameters for faecal contamination are the total and faecal coliforms. However, epidemiological studies, environmental resistance and the behaviour in the treatment systems, show that viruses are an important disease agent and even more resistant to disinfection than bacteria. Therefore, it is important to introduce viruses as a faecal indicator and to compare them with the traditional bacterial indicators. A waste stabilization pond system was evaluated in the municipality of Chocontá, Cundinamarca (Colombia), for the removal of faecal indicators (such as Escherichia coli, Streptococcus faecalis, Clostridium perfringens) and viruses like F+, somatic and Bacteroides fragilis phages. The system includes two facultative ponds in series with a flow of 1555 m3/day. Samples were collected at the entrance of the system, in the two ponds and from the final effluent. Results show a decrease between 0.3 and 4.7 logarithmic units in the bacterial indicators and between 1 and 4.6 logarithmic units with viral indicators.

  10. LC method for telithromycin in tablets: a stability-indicating assay.

    PubMed

    Vaucher, Lauren C; Paim, Clésio S; Lange, Alini D; Schapoval, Elfrides E S

    2009-01-21

    A liquid chromatographic (LC) method for the quantitative determination of telithromycin, the first member of the ketolides, which is a new class of macrolides, was developed. Analytical parameters were studied according to International Conference on Harmonization (ICH) guidelines. An Ace RP-18 octadecyl silane column (250 mm x 4.6 mm, 5 microm) maintained at 50 degrees C was used as the stationary phase, and methanol and 0.067 M potassium monobasic phosphate buffer pH 4.0 (55:45, v/v) were used as the mobile phase with UV detection at 265 nm. In forced degradation studies, the effects of acid, base, oxidation, UV light and temperature were investigated showing no interference in the drug peak. The method was linear (r=0.9999) at concentration ranging from 10.0 to 40.0 microg/mL, precise (intra-day relative standard deviation [RSD] and inter-day RSD values<2.0%), accurate (mean recovery=100.76%), specific and robust. Detection and quantitation limits were 0.0027 and 0.0082 microg/mL, respectively. The results showed the proposed method is suitable for its intended use. The validated method may be used to quantify telithromycin tablets and to determine the stability of the drug. The method is able to separate telithromycin from its degradation products and tablet excipients for its sensitivity and reproducibility. These results are in accordance with a previous microbiological assay study, which used the same tested conditions showing that the methods can be interchangeable.

  11. Stability-Indicating HPLC-UV Method for Vitamin D3 Determination in Solutions, Nutritional Supplements and Pharmaceuticals.

    PubMed

    Temova, Žane; Roškar, Robert

    2016-08-01

    A simple and fast high-performance liquid chromatography method with UV detection for determination of vitamin D3 in stability studies as well as in solutions, nutritional supplements and pharmaceuticals was developed. Successful separation of vitamin D3 from its degradation products was achieved on a Gemini C18 100 × 3.0 mm column using a mixture of acetonitrile and water (99:1, v/v) as а mobile phase. The method was successfully validated according to the ICH guidelines. The described reversed-phase HPLC method is favorable compared with other published HPLC-UV methods because of its stability-indicating nature, short run time (3.3 min) and wide analytical range with outstanding linearity, accuracy and precision. The method was further applied for quantification of vitamin D3 in selected liquid and solid nutritional supplements and prescription medicines, confirming its suitability for routine analysis. Degradation products, formed under stress conditions (hydrolysis, oxidation, photolysis and thermal degradation), were additionally elucidated by suitable equipment (LC-DAD-MS) to confirm the stability-indicating nature of the developed method.

  12. Age and thermal stability of particulate organic matter fractions indicate the presence of black carbon in soil

    NASA Astrophysics Data System (ADS)

    Leifeld, Jens; Heiling, Maria; Hajdas, Irka

    2014-05-01

    Black carbon (BC) from incomplete combustion is abundant in many soils. The age of black carbon is often higher than that of typical soil organic carbon (SOC) owing to its higher recalcitrance against microbial decomposition compared to plant residues. Also fossil BC may contribute to the high age of SOC. At the same time, the oxidative thermal stability of BC is known to be higher than that of SOC due to its chemical and physical structure. For a meaningful application of radiocarbon as an indicator for soil carbon age and turnover, the relative contribution of BC needs to be known but BC is difficult to separate physically from soil. Here we analyze particulate organic carbon (POC) fractions from four different field sites in Europe for their thermal stability using oxidative differential scanning calorimetry (DSC) and for their radiocarbon signature. POC may be particularly sensitive to BC 'contamination' because it was gained using a combination of size and density separation. One of these sites is essentially free of measurable amounts of BC. Each of the four sites comprised between five and eight individual POC samples taken from different spots. The radiocarbon signature and the calculated POC mean residence time of samples from three out of four sites indicated the presence of very old carbon, resulting in mean residence times (MRT) of several hundreds and up to 3700 years. In contrast, MRT's of POC from the virtually BC-free site were between 50 and 100 years. Two indicators for thermal stability of the POC fractions, i) the amount of heat released at temperatures > 450 °C and ii) the amount of heat released at 500 °C (where the latter represents the peak temperature of charcoal isolated from one of the samples) correlated both significantly and non-linearly with the samples MRT, indicating that samples with high BC content are older. Hence we can conclude that for an individual site with increasing abundance of BC both the age and the thermal stability

  13. A validated stability-indicating LC method for estimation of etoposide in bulk and optimized self-nano emulsifying formulation: Kinetics and stability effects

    PubMed Central

    Akhtar, Naseem; Talegaonkar, Sushama; Khar, Roop Kishan; Jaggi, Manu

    2012-01-01

    The present investigation was aimed to establish a validated stability-indicating liquid chromatographic method for the estimation of etoposide (ETP) in bulk drug and self-nano emulsifying formulation. ETP was successfully separated from the degradation products formed under stress conditions on LiChrospher 100 C18 reverse-phase column (a 250 mm × 4.6 mm i.d., 5-μm particle size) using 55:45 (v/v) acetonitrile–phosphate buffer saline (pH 4.5) as the mobile phase, at a flow rate of 1.0 mL min−1 and detection at 283 nm. The response was a linear function of analyte concentration (R2 > 0.9997) over the concentration range of 0.05–50 μg mL−1. The method was validated for precision, accuracy, robustness, sensitivity and specificity. The % recovery of ETP at three different levels (50%, 100% and 150%) ranged between 93.84% and 100.06% in optimized self-nano emulsifying formulation, Etosid® soft-gelatin capsule and Fytosid® injection. First-order degradation kinetics of ETP were observed under acidic and alkaline conditions. The method was also applied for the stability assessment of self-nano emulsifying formulation under accelerated conditions, the formulation was found to be stable at all storage conditions with the shelf-life of 2.37 years at 25 °C. The method holds promise for routine quality control of ETP in bulk, pharmaceutical formulations as well as in stability-indicating studies. PMID:23960824

  14. A validated stability-indicating LC method for estimation of etoposide in bulk and optimized self-nano emulsifying formulation: Kinetics and stability effects.

    PubMed

    Akhtar, Naseem; Talegaonkar, Sushama; Khar, Roop Kishan; Jaggi, Manu

    2013-01-01

    The present investigation was aimed to establish a validated stability-indicating liquid chromatographic method for the estimation of etoposide (ETP) in bulk drug and self-nano emulsifying formulation. ETP was successfully separated from the degradation products formed under stress conditions on LiChrospher 100 C18 reverse-phase column (a 250 mm × 4.6 mm i.d., 5-μm particle size) using 55:45 (v/v) acetonitrile-phosphate buffer saline (pH 4.5) as the mobile phase, at a flow rate of 1.0 mL min(-1) and detection at 283 nm. The response was a linear function of analyte concentration (R(2) > 0.9997) over the concentration range of 0.05-50 μg mL(-1). The method was validated for precision, accuracy, robustness, sensitivity and specificity. The % recovery of ETP at three different levels (50%, 100% and 150%) ranged between 93.84% and 100.06% in optimized self-nano emulsifying formulation, Etosid® soft-gelatin capsule and Fytosid® injection. First-order degradation kinetics of ETP were observed under acidic and alkaline conditions. The method was also applied for the stability assessment of self-nano emulsifying formulation under accelerated conditions, the formulation was found to be stable at all storage conditions with the shelf-life of 2.37 years at 25 °C. The method holds promise for routine quality control of ETP in bulk, pharmaceutical formulations as well as in stability-indicating studies.

  15. A validated stability-indicating liquid chromatographic method for the determination of retapamulin in topical dosage form.

    PubMed

    Nalwade, Santaji; Reddy, Vangala Ranga

    2014-03-01

    A sensitive, stability-indicating reversed-phase high-performance liquid chromatographic method is developed and validated for the quantitative determination of retapamulin in topical dosage form. The chromatographic separation is achieved by using a C18 column (XTerra RP 18 250 × 4.6 mm, 5 µm) at 30°C. The mobile phase comprises a mixture of 0.05M potassium dihydrogen phosphate buffer (pH 6.1), acetonitrile and methanol in the ratio of 35:50:15 (v/v/v). The flow rate is set at 1.0 mL/min and chromatograms are extracted at 243 nm using a photodiode array detector. The method is validated with respect to linearity, accuracy, precision, robustness and forced degradation studies, which further prove the stability-indicating supremacy of the method. During forced degradation studies, retapamulin is observed to be labile to oxidative and base hydrolysis stress and stable in thermal, photolytic and acid hydrolysis stress. The degradation products are well separated from the retapamulin peak, thus proving the stability-indicating superiority of the method. The method is found to be sensitive for retapamulin, with a detection limit of 25 ng/mL and a quantification limit of 80 ng/mL. The proposed method is found to be very sensitive and accurate for the determination of retapamulin in topical dosage form. The method is also demonstrated to be robust, because it is resistant to small variations of chromatographic variables such as pH, mobile phase composition, flow rate and column temperature.

  16. Stability study of fotemustine in PVC infusion bags and sets under various conditions using a stability-indicating high-performance liquid chromatographic assay.

    PubMed

    Dine, T; Khalfi, F; Gressier, B; Luyckx, M; Brunet, C; Ballester, L; Goudaliez, F; Kablan, J; Cazin, M; Cazin, J C

    1998-11-01

    The stability and compatibility of fotemustine, a nitrosourea anticancer agent, in 5% dextrose solution with polyvinyl chloride (PVC) containers and administration sets were studied under different conditions of temperature and light. The drug was diluted to 0.8 and 2 mg ml(-1) in 100 or 250 ml 5% dextrose injection solutions for 1-h simulated infusions using PVC bags and administration sets with protection from light. After preparation in the PVC bags containing 5% dextrose, fotemustine was also prepared at the same concentrations and stored at 4 degrees C for 48 h and at room temperature (22 degrees C) or at sunray exposure ( > 30 degrees C) over 8 h with or without protection from light. The solution samples were removed immediately at various time points of simulated infusions and storage, and stored at -20 degrees C until analysis. The physical compatibility with PVC and chemical stability in solution of fotemustine were assessed by visual examination and by measuring the concentration of the drug in duplicate using a stability-indicating high-performance chromatographic assay. When admixed with a 5% dextrose solution, fotemustine 2 and 0.8 mg ml(-1) was compatible and stable over 1-h of simulated infusion using PVC bags through PVC administration sets with protection from light. On the other hand, in the same diluent, fotemustine was compatible and stable with PVC bags for at least 8 h at 22 degrees C with protection from light and for at least 48 h at 4 degrees C with protection from light. There were no pH variation, no visual change, no color change, no visible precipitation and no loss of the drug. Conversely, when the solutions were exposed to light (ambient or solar), the drug concentration decreased rapidly, leading to the production of a degradation product as shown by mass spectral analysis and a discoloration of the solutions. Finally, in all cases, no DEHP (di-2-ethylhexyl phthalate) was detected in the injection solution.

  17. Quantification of potential impurities by a stability indicating UV-HPLC method in niacinamide active pharmaceutical ingredient.

    PubMed

    Thomas, Saji; Bharti, Amber; Tharpa, Kalsang; Agarwal, Ashutosh

    2012-02-23

    A sensitive, stability indicating reverse phase UV-HPLC method has been developed for the quantitative determination of potential impurities of niacinamide active pharmaceutical ingredient. Efficient chromatographic separation was achieved on C18 stationary phase in isocratic mode using simple mobile phase. Forced degradation study confirmed that the newly developed method was specific and selective to the degradation products. Major degradation of the drug substance was found to occur under oxidative stress conditions to form niacinamide N-oxide. The method was validated according to ICH guidelines with respect to specificity, precision, linearity and accuracy. Regression analysis showed correlation coefficient value greater than 0.999 for niacinamide and its six impurities. Detection limit of impurities was in the range of 0.003-0.005% indicating the high sensitivity of the newly developed method. Accuracy of the method was established based on the recovery obtained between 93.3% and 113.3% for all impurities.

  18. Analytical Stability-Indicating Methods for Alogliptin in Tablets by LC-CAD and LC-UV.

    PubMed

    Bertol, Charise Dallazem; Friedrich, Maria Tereza; Carlos, Graciela; Froehlich, Pedro Eduardo

    2017-03-01

    Stability-indicating LC methods using a UV detector and a charged aerosol detector (CAD) simultaneously were validated for the assessment of alogliptin (ALG) in tablets. The analysis was performed on a C8 column (250 × 4.6 mm, 5 μm) at a flow of 0.8 mL/min, using acetonitrile-10 mM ammonium acetate buffer (pH 3.5; 90 + 10, v/v) as mobile phase and UV detection at 275 nm. Validation followed the International Conference on Harmonization guidelines. The method was linear over the range of 25-200 μg/mL. Normality of the residuals showed a normal distribution, no autocorrelation, and homoscedasticity. LODs were 6.25 and 2.65 µg/mL and LOQs were 20.85 and 8.84 µg/mL for the CAD and the UV detector, respectively. The methods were precise and accurate. Excipients and degradation products did not interfere in the methods in studies of specificity. None of the factors studied in the analysis of robustness had a significant effect on the quantification of the ALG by the Pareto chart. The results of the assay obtained with LC-CAD and LC-UV were similar. The methods could be considered interchangeable and stability-indicating, and can be applied as an appropriate QC tool for analysis of ALG in tablets.

  19. Validated stability-indicating HPLC-DAD method for determination of the recently approved hepatitis C antiviral agent daclatasvir.

    PubMed

    Baker, M M; El-Kafrawy, D S; Mahrous, M S; Belal, T S

    2017-02-07

    A comprehensive stability indicating HPLC with diode array detection method was developed for the determination of the recently approved antiviral drug daclatasvir dihydrochloride (DCV) which is used for the treatment of chronic Hepatitis C Virus (HCV) genotype 3 infection. Effective chromatographic separation was achieved using Waters C8 column (4.6×250mm, 5μm particle size) with isocratic elution of the mobile phase composed of mixed phosphate buffer pH 2.5 and acetonitrile in the ratio of 75:25 (by volume). The mobile phase was pumped at a flow rate of 1.2mL/min, and quantification of DCV was based on measuring its peak areas at 306nm. DCV eluted at retention time 5.4min. Analytical performance of the proposed HPLC procedure was thoroughly validated with respect to system suitability, linearity, range, precision, accuracy, specificity, robustness, detection and quantification limits. The linearity range was 0.6-60μg/mL with correlation coefficient>0.99999. The drug was subjected to forced degradation conditions of neutral, acidic and alkaline hydrolysis, oxidation and thermal degradation. The proposed method proved to be stability-indicating by resolution of the drug from its forced-degradation products. The validated HPLC method was successfully applied to analysis of the cited drug in its tablets.

  20. Development, Optimization, and Validation of a Green and Stability-Indicating HPLC Method for Determination of Daptomycin in Lyophilized Powder.

    PubMed

    Tótoli, Eliane Gandolpho; Salgado, Hérida Regina Nunes

    2015-01-01

    Daptomycin is an antimicrobial that plays an important role in clinical practice today because it is considered a promising drug to combat resistant strains, such as methicilin and vancomycin-resistant Gram-positive bacteria. Considering the analysis of daptomycin in a pharmaceutical dosage form, the only method found in literature uses potentially toxic organic solvents. Therefore, the objective of this work was to develop a green and stability-indicating HPLC method for determination of daptomycin in lyophilized powder. The mobile phase was ethanol-water (55+45, v/v) at pH 4.5 pumped at a flow rate of 0.6 mL/min. A C18 column was used, and UV detection was performed at 221 nm. Stress degradation studies were conducted in order to demonstrate the specificity and stability-indicating capability of the method. The method was validated according to International Conference on Harmonization guidelines, proving to be linear (r=0.9996), precise, accurate, robust (demonstrated by the Plackett-Burman model), and specific within the range 20-70 μg/mL. The retention time of daptomycin was 5.8 min. It can be concluded that the validated method can be a fast, safe, and environmentally friendly alternative for the analysis of daptomycin.

  1. Stability-indicating HPTLC method for simultaneous determination of nateglinide and metformin hydrochloride in pharmaceutical dosage form.

    PubMed

    Thomas, Asha Byju; Patil, Shrikrushna Digambar; Nanda, Rabindra Kumar; Kothapalli, Lata Prasad; Bhosle, Shital Shridhar; Deshpande, Avinash Devidas

    2011-10-01

    A stability indicating high performance thin layer chromatography (HPTLC) method was developed and validated for determination of two anti-diabetic drugs, nateglinide and metformin hydrochloride in co-formulations. Study was performed on pre-coated silica gel HPTLC plates using chloroform:ethyl acetate:acetic acid (4:6:0.1 v/v/v) as the mobile phase. A TLC scanner set at 216 nm was used for direct evaluation of the chromatograms in the reflectance/absorbance mode. Method was validated according to ICH guidelines. The correlation coefficients of calibration curves were found to be 0.996 and 0.995 in the concentration range of 200-2400 and 500-3000 ng band(-1) for nateglinide and metformin, respectively. The method had an accuracy of 99.72% for nateglinide and 100.08% for metformin hydrochloride. The method had the potential to determine these drugs simultaneously from dosage forms without any interference of the tablets excipients. Nateglinide and metformin hydrochloride were also subjected to acid, base, oxidation, wet, heat and photo-degradation studies. The degradation products obtained were well resolved from the pure drugs with significantly different Rf values. As the method could effectively separate the drugs from its degradation products, it can be used for stability-indicating analysis.

  2. Development and validation of a stability indicating RP-UPLC method for determination of quetiapine in pharmaceutical dosage form.

    PubMed

    Trivedi, Rakshit Kanubhai; Patel, Mukesh C

    2011-01-01

    The present work reports a stability indicating reversed phase ultra performance liquid chromatography (RP-UPLC) method for the quantitative determination of quetiapine in pharmaceutical dosage form. The chromatographic separation is performed on an Agilent Eclipse Plus C18, RRHD 1.8 μm (50 mm x 2.1 mm) column using gradient elution. The optimized mobile phase consists of 0.1 % aqueous triethylamine (pH 7.2) as a solvent-A and 80:20 v/v mixture of acetonitrile and methanol as solvent-B. The eluted compounds are monitored at 252 nm wavelength using a UV detector. The developed method separates quetiapine from its five impurities/degradation products within a run time of 5 min. Stability indicating capability of the developed method is established by analyzing forced degradation samples in which the spectral purity of quetiapine is ascertained along with the separation of degradation products from analyte peak. The developed RP-UPLC method is validated as per International Conference on Harmonization (ICH) guidelines with respect to system suitability, specificity, precision, accuracy, linearity, robustness and filter compatibility.

  3. A stability-indicating HPLC method for the determination of bazedoxifene acetate and its related substances in active pharmaceutical ingredient.

    PubMed

    Visweswara Rao, Karri; Reddy, Kesareddy Padmaja; Kumari, Kondapaturu Siva; Srinivas, Mudigonda

    2013-03-01

    A simple, cost effective, stability-indicating reversed-phase high-performance liquid chromatography method was developed for the quantitative determination of bazedoxifene acetate (BAZ) drug substance in the presence of its impurities and degradation products. The method was developed using an X-terra RP-18, 150 × 4.6 mm, 3.5 μm column with a mobile phase containing solvent A, a mixture of 10 mM K(2)HPO(4) (pH 8.3) and acetonitrile in the ratio of 70:30 (v/v); and solvent B, a mixture of water and acetonitrile in the ratio 10:90 (v/v). The eluted compounds were monitored at 220 nm, and within a short run time of 18 min, BAZ and its impurities were satisfactorily separated with resolution more than 2.0. BAZ was subjected to stress degradation and found to be sensitive towards acidic, basic, oxidative, thermal and hydrolytic stress conditions and stable in photo degradation conditions. The degradation products were well resolved from BAZ peak and its impurities; the mass balance in each case was more than 99.5%, proving the stability-indicating power of the method. The developed method was validated as per International Conference on Harmonization guidelines with respect to specificity, linearity (correlation coefficient > 0.9994), limit of detection, limit of quantification, accuracy (recovery range 96.3 to 102.1%), precision (relative standard deviation < 2.8%) and robustness.

  4. Simultaneous determination of aliskiren and hydrochlorothiazide from their pharmaceutical preparations using a validated stability-indicating MEKC method.

    PubMed

    Sangoi, Maximiliano S; Wrasse-Sangoi, Micheli; Oliveira, Paulo R; Rolim, Clarice M B; Steppe, Martin

    2011-08-01

    A stability-indicating MEKC method was developed and validated for the simultaneous determination of aliskiren (ALI) and hydrochlorothiazide (HCTZ) in pharmaceutical formulations using ranitidine as an internal standard (IS). Optimal conditions for the separation of ALI, HCTZ and its major impurity chlorothiazide (CTZ), IS and degradation products were investigated. The method employed 47 mM Tris buffer and 47 mM anionic detergent SDS solution at pH 10.2 as the background electrolyte. MEKC method was performed on a fused-silica capillary (40 cm) at 28°C. Applied voltage was 26 kV (positive polarity) and photodiode array (PDA) detector was set at 217 nm. The method was validated in accordance with the ICH requirements. The method was linear over the concentration range of 5-100 and 60-1200 μg/mL for HCTZ and ALI, respectively (r(2) >0.9997). The stability-indicating capability of the method was established by enforced degradation studies combined with peak purity assessment using the PDA detection. Precision and accuracy evaluated by RSD were lower than 2%. The method proved to be robust by a fractional factorial design evaluation. The proposed MEKC method was successfully applied for the quantitative analysis of ALI and HCTZ both individually and in a combined dosage tablet formulation to support the quality control.

  5. Stability indicating HPLC-UV method for detection of curcumin in Curcuma longa extract and emulsion formulation.

    PubMed

    Syed, Haroon Khalid; Liew, Kai Bin; Loh, Gabriel Onn Kit; Peh, Kok Khiang

    2015-03-01

    A stability-indicating HPLC-UV method for the determination of curcumin in Curcuma longa extract and emulsion was developed. The system suitability parameters, theoretical plates (N), tailing factor (T), capacity factor (K'), height equivalent of a theoretical plate (H) and resolution (Rs) were calculated. Stress degradation studies (acid, base, oxidation, heat and UV light) of curcumin were performed in emulsion. It was found that N>6500, T<1.1, K' was 2.68-3.75, HETP about 37 and Rs was 1.8. The method was linear from 2 to 200 μg/mL with a correlation coefficient of 0.9998. The intra-day precision and accuracy for curcumin were ⩽0.87% and ⩽2.0%, while the inter-day precision and accuracy values were ⩽2.1% and ⩽-1.92. Curcumin degraded in emulsion under acid, alkali and UV light. In conclusion, the stability-indicating method could be employed to determine curcumin in bulk and emulsions.

  6. Development of stability-indicating UHPLC method for the quantitative determination of silodosin and its related substances.

    PubMed

    Shaik, Jafer Vali; Saladi, Shantikumar; Sait, Shakil S

    2014-08-01

    A novel, specific and stability-indicating reversed-phase (RP) ultra-high-performance liquid chromatography (UHPLC) method, which is mass compatible, was developed and validated for the quantitative determination of silodosin and its related substances. Silodosin was subjected to stress conditions like hydrolysis (acid and basic), oxidation, photolysis and thermal degradation, as per the guidelines of the International Conference Harmonization, to show that the method is stability-indicating. The proposed UHPLC method has a resolution of greater than 2.0 between silodosin and its process-related impurities. The chromatographic separation was achieved on an Agilent Poroshell 120 EC-C18 column (50 × 4.6mm i.d.; particle size, 2.7 µm). The method employed a linear gradient elution using a mobile phase consisting of acetonitrile and 10 mM ammonium acetate buffer with 0.1% triethyl amine, with pH adjusted to 6.0, monitored at 273 nm. The developed RP-LC method was validated with respect to linearity, accuracy, precision and robustness. The known process impurities were separated and their structure was confirmed by using liquid chromatography-mass spectrometry and direct mass analysis.

  7. Development and validation of a stability-indicating LC method for the assay of lodenafil carbonate in tablets.

    PubMed

    Codevilla, Cristiane Franco; Lemos, Alice Machado; Delgado, Leila Schreiner; Rolim, Clarice Madalena Bueno; Adams, Andréa Inês Horn; Bergold, Ana Maria

    2011-08-01

    A stability-indicating liquid chromatographic method has been developed for the quantitative determination of lodenafil carbonate in tablets. The method employs a Synergi Fusion C18 column (250 × 4.6 mm, i.d., 4 μm particle size), with mobile phase consisting of a mixture of methanol-acetic acid 0.1% pH 4.0 (65:35, v/v) and UV detection at 290 nm, using a photodiode array detector. A linear response (r = 0.9999) was observed in the range of 10-80 μg/mL. The method showed good recoveries (average 100.3%) and also intra and inter-day precision (RSD < 2.0%). Validation parameters as specificity and robustness were also determined. Specificity analysis showed that no impurities or degradation products were co-eluting with the lodenafil carbonate peak. The method was found to be stability-indicating and due to its simplicity and accuracy can be applied for routine quality control analysis of lodenafil carbonate in tablets.

  8. Stability-indicating micellar electrokinetic chromatography technique for simultaneous measurement of delapril and manidipine from a combination drug formulation.

    PubMed

    Todeschini, Vítor; Sangoi, Maximiliano da Silva; Meira, Alianise da Silva; Miron, Diogo; Lange, Alini Dall Cortivo; Volpato, Nadia Maria

    2014-01-01

    A stability-indicating micellar electrokinetic chromatography (MEKC) method was developed and validated for simultaneous analysis of delapril (DEL) and manidipine (MAN) using salicylic acid as an internal standard. The MEKC method was performed using a fused-silica capillary (effective length of 72 cm) with 50 mM of borate buffer and 5 mM of anionic surfactant sodium dodecylsulfate at pH 9.0 as the background electrolyte. The separation was achieved at 25 kV applied voltage and 35 degrees C. The injection was performed at 50 mbar for 5 s, with detection at 208 nm. The method was linear in the range of 15-150 microg/mL (r2 = 0.9966) for DEL and 5-50 microg/mL (r2 = 0.9985) for MAN with adequate results for the precision (< or = 1.87%) and accuracy (98.94% for DEL and 100.65% for MAN). The specificity of the method and its stability-indicating capability was demonstrated through forced degradation studies, which showed that there was no interference from the excipients. The Plackett-Burman experimental design was used for robustness evaluation, giving results within the acceptable range. The method was successfully applied for analysis of the drugs, and the results were compared to an LC method, resulting in nonsignificant differences (P = 0.78 and 0.84 for DEL and MAN, respectively).

  9. Stability-Indicating High-Performance Liquid Chromatography Assay for the Determination of Sulthiame in Pharmaceutical Dosage Forms

    PubMed Central

    Haidar, Ammar; Kabiche, Sofiane; Majoul, Elyes; Balde, Issa-Bella; Fontan, Jean-Eudes; Cisternino, Salvatore; Schlatter, Joël

    2016-01-01

    A stability-indicating assay by reversed-phase high performance liquid chromatography method was developed and validated for the determination of sulthiame (STM). The chromatographic separation was achieved on a reversed-phase NovaPack C18 column and an isocratic mobile phase consisting of deionized water:methanol (70:30, v/v). The flow rate was 1.0 mL/min (ultraviolet detection at 210 nm). The STM was separated within 2.83 min. The linearity of the method was demonstrated in the range of 20.0–200.0 μg/mL and a coefficient of determination of r2 = 0.9999. The limits of detection and quantification were 4.2 and 9.5 μg/mL, respectively. The intraday and interday precisions were less than 1%. Accuracy of the method ranged from 98.3% to 101.7%, with a relative standard deviation of <1%. STM was degraded by accelerated breakdown in alkaline, acidic, or oxidative stress conditions. This method allows accurate and reliable determination of STM for drug stability assay in pharmaceutical studies. PMID:27625574

  10. A stability-Indicating HPLC Method for Simultaneous Determination of Creatine Phosphate Sodium and its Related Substances in Pharmaceutical Formulation

    PubMed Central

    Xie, Zengkun; Wei, Lihua; Yang, Qin; Yang, Min; Pan, Hongchun; Liu, Hong

    2016-01-01

    The objective of the study was to develop a simple, specific and stability-indicating HPLC method for the simultaneous determination of creatine phosphate sodium (CPS) and its related substances in pharmaceutical formulation. Separation of creatine phosphate sodium from its major process impurities and degradation products was achieved on a Hypersil BDS C18 column (250 × 4.6 mm, 5 μm) with an aqueous mobile phase containing 0.2% (w/v) tetrabutylammonium hydroxide (TAH) and 0.2% (w/v) monopotassium phosphate adjusted to pH 6.6 with orthophosphoric acid at a flow rate of 1.0 mL min-1. The analytes were detected at 210 nm. Different chromatographic parameters were carefully optimized. The relative response factors for creatine, creatinine and creatinine phosphate disodium salt relative to CPS were determined. The method has been validated with respect to solution stability, system suitability, LOD, LOQ, linearity, accuracy, precision, specificity and robustness. The validation criteria were met in all cases. The developed method was successfully applied to determine the purity of CPS in pharmaceutical formulation. PMID:27610152

  11. Development and validation of a stability-indicating analytical method for the quantitation of oxytocin in pharmaceutical dosage forms.

    PubMed

    Chaibva, F A; Walker, R B

    2007-01-04

    A single stability-indicating assay for oxytocin (OT) in pharmaceutical dosage forms using gradient elution over 21 min has been reported in the literature. Furthermore, published and compendial methods for the analysis of OT containing dosage forms also involve using HPLC with gradient elution and complicated mobile phases that include hydrophobic ion pairing agents. A simple isocratic and stability-indicating assay was developed and validated. The conditions are as follows, column: Phenomenex C18 Hypersil, 5 microm packing, 4.6 mm x 150 mm with acetonitrile-phosphate buffer (pH 5; 0.08 M) (20:80) as the mobile phase with UV detection at 220 nm The method was found to be specific for OT in the presence of degradation products and chlorbutol (preservative) with an overall analytical run time of 16 min. Accuracy was determined to be 0.77-1.18% bias for all samples tested. Intra-assay precision (repeatability) was found to be 0.22-1.04%R.S.D. while the inter-day precision (intermediate precision) was found to be 1.27-1.68%R.S.D. for the samples studied. The calibration curve was found to be linear with the equation y = 1.81x + 0.02 and a linear regression coefficient of 0.9991 over the range 0.4-12.0 IU/ml. The LOD and the LOQ were determined to be 0.1 and 0.4 IU/ml, respectively. Syntocinon, a commercially available dosage form of OT was assayed resulting in 100.5-106.6% recovery of the label claim and an average of 10.04 IU/ml.

  12. Development and Validation of Stability-indicating HPLC Method for Betamethoasone Dipropionate and Related Substances in Topical Formulation.

    PubMed

    Vairale, A S; Sivaswaroop, P; Bandana, S

    2012-03-01

    A gradient reversed phase HPLC method was developed and validated for analysis of betamethasone dipropionate, its related substances and degradation products, using Altima C(18) column (250×4.6 mm, 5 μm) with a flow rate of 1.0 ml/min and detection wavelength of 240 nm. The mobile phase A is a mixture of water, tetrahydrofuran and acetonitrile in the ratio of 90:4:6 (v/v/v) while mobile phase B is a mixture of acetonitrile, tetrahydrofuran, water and methanol in the ratio of 74:2:4:20 (v/v/v/v). The samples were analyzed using 20 μl injection volume and the column temperature was maintained at 50°. The limit of detection and limit of quantitation were found to be 0.02 μg/ml and 0.07 μg/ml, respectively. The stability-indicating capability of method was established by forced degradation studies and method demonstrated successful separation of drug, its related substances and degradation products. The method was validated as per the International Conference on Harmonization guidelines. The developed method is linear in the range of 0.07 to 200% of specification limits established for all the known related substances; betamethasone17-propionate, betamethasone 21-propionate, betamethasone 17-propionate-21-acetate (RSD <5, 2, 1%, respectively, r(2)=09991-0.9999 for sample concentration of 100 μg/ml). The method is sensitive, specific, linear, accurate, precise and stability indicating for the quantitation of drug, its related substances and other degradation compounds.

  13. Development and Validation of Stability-indicating HPLC Method for Betamethoasone Dipropionate and Related Substances in Topical Formulation

    PubMed Central

    Vairale, A. S.; Sivaswaroop, P.; Bandana, S.

    2012-01-01

    A gradient reversed phase HPLC method was developed and validated for analysis of betamethasone dipropionate, its related substances and degradation products, using Altima C18 column (250×4.6 mm, 5 μm) with a flow rate of 1.0 ml/min and detection wavelength of 240 nm. The mobile phase A is a mixture of water, tetrahydrofuran and acetonitrile in the ratio of 90:4:6 (v/v/v) while mobile phase B is a mixture of acetonitrile, tetrahydrofuran, water and methanol in the ratio of 74:2:4:20 (v/v/v/v). The samples were analyzed using 20 μl injection volume and the column temperature was maintained at 50°. The limit of detection and limit of quantitation were found to be 0.02 μg/ml and 0.07 μg/ml, respectively. The stability-indicating capability of method was established by forced degradation studies and method demonstrated successful separation of drug, its related substances and degradation products. The method was validated as per the International Conference on Harmonization guidelines. The developed method is linear in the range of 0.07 to 200% of specification limits established for all the known related substances; betamethasone17-propionate, betamethasone 21-propionate, betamethasone 17-propionate-21-acetate (RSD <5, 2, 1%, respectively, r2=09991-0.9999 for sample concentration of 100 μg/ml). The method is sensitive, specific, linear, accurate, precise and stability indicating for the quantitation of drug, its related substances and other degradation compounds. PMID:23325990

  14. Stability-indicating methods for the determination of famciclovir in the presence of its alkaline-induced degradation product.

    PubMed

    Lotfy, Hayam Mahmoud; Abd El-Moneim Abosen, Mona M; El-Bardicy, Mohamed Galal

    2010-04-01

    Five sensitive, selective and precise stability-indicating methods are presented for the determination of famciclovir (FCV) in the presence of its alkaline-induced degradation product. Method A utilizes the first derivative spectrophotometry at 321 nm. Method B depends on using the first derivative of the ratio spectrophotometry (DD(1)) by measurement of the amplitude at 256 nm. Method C is based on the reaction of FCV with hydroxylamine to form hydroxamic acid, causing the hydroxamic acid to react with triferric ion to form ferric hydroxamate that is measured at 503 nm. Method D is based on the separation of FCV from its degradation product followed by densitometric measurement of the bands at 304 nm. The separation was carried out on silica gel 60 F(254), using chloroform: methanol (70:30, v/v) as a mobile phase. Method E is based on a high performance liquid chromatographic (HPLC) separation of FCV from its degradation product using an ODS column with a mobile phase consisting of methanol-50 mM dipotassium hydrogen phosphate (25:75, v/v, pH 3.0)with UV detection at 304 nm. Regression analysis showed good correlation in the concentration ranges 16-72 microg/ml, 40-240 microg/ml, 40-240 microg/ml, 0.75-5.25 microg/band and 20-240 microg/ml with percentage recoveries of 99.65 +/- 0.85, 100.27 +/- 0.91, 99.72 +/- 0.84, 100.65 +/- 1.52 and 99.88 +/- 0.50 for methods A, B, C, D and E, respectively. These methods are suitable as stability-indicating methods for the determination of FCV in the presence of its degradation product either in bulk powder or in pharmaceutical formulation. Statistical analysis of the results has been carried out revealing high accuracy and good precision.

  15. Stability indicating validated HPLC method for quantification of levothyroxine with eight degradation peaks in the presence of excipients.

    PubMed

    Shah, R B; Bryant, A; Collier, J; Habib, M J; Khan, M A

    2008-08-06

    A simple, sensitive, accurate, and robust stability indicating analytical method is presented for identification, separation, and quantitation of l-thyroxine and eight degradation impurities with an internal standard. The method was used in the presence of commonly used formulation excipients such as butylated hydroxyanisole, povidone, crospovidone, croscarmellose sodium, mannitol, sucrose, acacia, lactose monohydrate, confectionary sugar, microcrystalline cellulose, sodium laurel sulfate, magnesium stearate, talc, and silicon dioxide. The two active thyroid hormones: 3,3',5,5'-tetra-iodo-l-thyronine (l-thyroxine-T4) and 3,3',5-tri-iodo-l-thyronine (T3) and degradation products including di-iodothyronine (T2), thyronine (T0), tyrosine (Tyr), di-iodotyrosine (DIT), mono-iodotyrosine (MIT), 3,3',5,5'-tetra-iodothyroacetic acid (T4AA) and 3,3',5-tri-iodothyroacetic acid (T3AA) were assayed by the current method. The separation of l-thyroxine and eight metabolites along with theophylline (internal standard) was achieved using a C18 column (25 degrees C) with a mobile phase of trifluoroacetic acid (0.1%, v/v, pH 3)-acetonitrile in gradient elution at 0.8 ml/min at 223 nm. The sample diluent was 0.01 M methanolic NaOH. Method was validated according to FDA, USP, and ICH guidelines for inter-day accuracy, precision, and robustness after checking performance with system suitability. Tyr (4.97 min), theophylline (9.09 min), MIT (9.55 min), DIT (11.37 min), T0 (11.63 min), T2 (14.47 min), T3 (16.29 min), T4 (17.60 min), T3AA (22.71 min), and T4AA (24.83 min) separated in a single chromatographic run. Linear relationship (r2>0.99) was observed between the peak area ratio and the concentrations for all of the compounds within the range of 2-20 microg/ml. The total time for analysis, equilibration and recovery was 40 min. The method was shown to separate well from commonly employed formulation excipients. Accuracy ranged from 95 to 105% for T4 and 90 to 110% for all other

  16. A Validated Stability-Indicating HPLC Method for Simultaneous Determination of Amoxicillin and Enrofloxacin Combination in an Injectable Suspension.

    PubMed

    Batrawi, Nidal; Wahdan, Shorouq; Al-Rimawi, Fuad

    2017-02-16

    The combination of amoxicillin and enrofloxacin is a well-known mixture of veterinary drugs; it is used for the treatment of Gram-positive and Gram-negative bacteria. In the scientific literature, there is no high-performance liquid chromatography (HPLC)-UV method for the simultaneous determination of this combination. The objective of this work is to develop and validate an HPLC method for the determination of this combination. In this regard, a new, simple and efficient reversed-phase HPLC method for simultaneous qualitative and quantitative determination of amoxicillin and enrofloxacin, in an injectable preparation with a mixture of inactive excipients, has been developed and validated. The HPLC separation method was performed using a reversed-phase (RP)-C18e (250 mm × 4.0 mm, 5 μm) column at room temperature, with a gradient mobile phase of acetonitrile and phosphate buffer containing methanol at pH 5.0, a flow rate of 0.8 mL/min and ultraviolet detection at 267 nm. This method was validated in accordance with the Food and Drug Administration (FDA) and the International Conference on Harmonisation (ICH) guidelines and showed excellent linearity, accuracy, precision, specificity, robustness, ruggedness, and system suitability results within the acceptance criteria. A stability-indicating study was also carried out and indicated that this method can also be used for purity and degradation evaluation of these formulations.

  17. Stability of Asp(B28) Insulin Exposed to Modified and Unmodified Polypropylene.

    PubMed

    Fristrup, Charlotte J; Jankova, Katja; Eskimergen, Rüya; Bukrinsky, Jens T; Hvilsted, Soren

    2015-01-01

    Polypropylene (PP) plates have been modified with two different hydrophilic polymeric materials, poly(N,N-dimethylacrylamide) (poly(DMAAm)) and poly(poly(ethylene glycol)methacrylate) (poly(PEGMA)) in order to reduce insulin adsorption when the plates were exposed to insulin aspart (Asp(B28) insulin). The influence of surface modification on the chemical and physical stability of Asp(B28) insulin was evaluated by two chromatographic methods, size exclusion chromatography (SEC) and reverse phase high pressure liquid chromatography (RP-HPLC) and the Thioflavin T assay. A clear difference in the stability of Asp(B28) insulin was observed between the three tested surfaces. PP coated with poly(DMAAm) resulted in a poor chemical stability and a significantly improved physical stability compared with unmodified PP. In addition to this a lower phenol concentration was observed for the poly(DMAAm) coating. The results from the poly(PEGMA) coating looked very promising with respect to the stability of Asp(B28) insulin in comparison with the data from unmodified PP and the poly(DMAAm) coating. Two hydrophilic coatings have been tested and surprisingly a difference in Asp(B28) insulin stability was observed. Therefore, Asp(B28) insulin adsorption and stability will be influenced by more than the hydrophilicity of the surface.

  18. Development and validation of a stability indicating LC method for the assay and related substances determination of exemestane, an aromatase inhibitor.

    PubMed

    Suresh Kumar, R; Narasimha Naidu, M; Srinivasulu, Kasa; Raja Sekhar, K; Veerender, M; Srinivasu, M K

    2009-12-05

    A selective stability indicating HPLC method was developed and validated for quantification of impurities (process related and degradants) and assay determination of Exemestane. Stability indicating power of the method was established by forced degradation experiments and mass balance study. The chromatographic separation was achieved with Hypersil BDS-C-18 using gradient elution. The developed method is validated for parameters like accuracy, linearity, LOD, LOQ, ruggedness. Box-Behnken experimental design was applied to check the robustness of the method.

  19. Development and Validation of Stability-Indicating Method for the Simultaneous Determination of Ketoconazole and Beauvericin in Pharmaceutical Tablets.

    PubMed

    Tian, Tingting; Yang, Min; Zhao, Zhongxi; Luan, Yuxia; Tang, Xuan; Zhu, Meihua; Liu, Yan

    2016-03-01

    In this work, a stability-indicating high-performance liquid chromatography (HPLC) method was developed and validated for the simultaneous analysis of ketoconazole (KCZ) and beauvericin (BEA) as well as their degradation products in the combination tablets. KCZ is a synthetic broad-spectrum antifungal agent with the risk of hepatoxicity. However, it was found that the combined use of KCZ and BEA in their low dose had not only maintained the antifungal activity of KCZ but also significantly reduced the liver toxicity. The method development was started from forced degradation studies including acidic, basic, oxidative, thermal and photolytic degradations in the solution mixtures of KCZ and BEA. The forced degradation study results indicate that hydrolysis and oxidation were the major degradation pathways for KCZ while BEA mainly decomposed under basic hydrolytic condition. The newly developed HPLC method was validated according to the International Conference on Harmonization (ICH) guidelines with respect to specificity, linearity, precision, accuracy, limits of detection and quantification and robustness. The method validation results indicate that the new HPLC method could be successfully applied in the simultaneous detection and quantitation of KCZ and BEA and their degradation products. For example, the accuracy and the precision of the method were determined by a recovery study at 80, 100 and 120% of the tablet dosage levels. The recovery was found to be 99.6-100.2 for both analytes with a relative standard deviation of no more than 1.2% (n = 5) at any concentration level. This new method can be used for further development of various KCZ and BEA combination drug products.

  20. Stability-indicating High-performance Liquid Chromatography Method for Simultaneous Determination of Aminophylline and Chlorpheniramine Maleate in Pharmaceutical Formulations

    PubMed Central

    Ali, A.; Ahmed, M.; Mahmud, T.; Qadir, M. A.; Nadeem, K.; Saleem, A.

    2015-01-01

    The present work deals with the development and validation of method for simultaneous determination of antihistaminic drugs in pharmaceutical formulations. A precise, specific and accurate reverse phase-high-performance liquid chromatography method for the simultaneous measurement of aminophylline and chlorpheniramine maleate was developed. The separation of drugs was achieved on C-18 (5 μm, 250×4.6 mm) high-performance liquid chromatography column. The runtime for analysis was 10 min. Mobile phase is mixture containing dilute H2SO4:methanol (60:40% v/v) with flow rate adjusted at 1.5 ml/min. The detection of components was performed at a wavelength of 264 nm. Retention times of aminophylline and chlorphinramine maleate were found to be 2.00 and 3.25 min, respectively. Linearity was found in the range of 16-24 μg/ml for chlorpheniramine maleate and 102.4-153.6 μg/ml for aminophylline with a correlation coefficient of 0.9998 and 0.9996, respectively. High peak purity index of 99.99% indicated the complete separation of analytes in the presence of degradation products is justification of method stability. Linearity, accuracy, specificity, precision and robustness studies were performed for method validation. PMID:26798164

  1. Robust and Rugged Stability-Indicating HPLC Method for the Determination of Plerixafor and Its Related Impurities in Drug Substances.

    PubMed

    Bapatu, Hanimi Reddy; Maram, Ravi Kumar; Murthy, R Satyanarayana

    2015-10-01

    A novel, reversed-phase high-performance liquid chromatographic method was developed and validated for the determination of related substances in Plerixafor (PLX) drug substance. PLX is an immunostimulant used to mobilize hematopoietic stem cells in cancer patients. The method is efficient for estimation of all degradation and process-related impurities. The method was developed using the Phenomenex Luna L11 column using the gradient program with mobile phase A and mobile phase B, where mobile phase A consists of pH 2.0 1-heptanesulfonic acid sodium salt buffer and acetonitrile in the ratio of 80:20 (v/v) and mobile phase B consists of pH 2.0 1-heptanesulfonic acid sodium salt buffer and acetonitrile in the ratio of 20:80 (v/v). PLX and its impurities were monitored at 210 nm. The present work is describing the role of ion-pair reagent in the separation of polar compounds. PLX was subjected to various stress conditions of oxidative, acid, base, hydrolytic, thermal, humidity and photolytic degradations. The degradation products were well separated from each other and with the main peak, demonstrating the stability-indicating power of the method. The performance of the method was validated according to the present ICH guidelines for specificity, limit of detection, limit of quantification, linearity, accuracy, precision, ruggedness and robustness.

  2. Measuring sperm whales from their clicks: stability of interpulse intervals and validation that they indicate whale length.

    PubMed

    Rhinelander, Marcus Q; Dawson, Stephen M

    2004-04-01

    Multiple pulses can often be distinguished in the clicks of sperm whales (Physeter macrocephalus). Norris and Harvey [in Animal Orientation and Navigation, NASA SP-262 (1972), pp. 397-417] proposed that this results from reflections within the head, and thus that interpulse interval (IPI) is an indicator of head length, and by extrapolation, total length. For this idea to hold, IPIs must be stable within individuals, but differ systematically among individuals of different size. IPI stability was examined in photographically identified individuals recorded repeatedly over different dives, days, and years. IPI variation among dives in a single day and days in a single year was statistically significant, although small in magnitude (it would change total length estimates by <3%). As expected, IPIs varied significantly among individuals. Most individuals showed significant increases in IPIs over several years, suggesting growth. Mean total lengths calculated from published IPI regressions were 13.1 to 16.1 m, longer than photogrammetric estimates of the same whales (12.3 to 15.3 m). These discrepancies probably arise from the paucity of large (12-16 m) whales in data used in published regressions. A new regression is offered for this size range.

  3. Measuring sperm whales from their clicks: Stability of interpulse intervals and validation that they indicate whale length

    NASA Astrophysics Data System (ADS)

    Rhinelander, Marcus Q.; Dawson, Stephen M.

    2004-04-01

    Multiple pulses can often be distinguished in the clicks of sperm whales (Physeter macrocephalus). Norris and Harvey [in Animal Orientation and Navigation, NASA SP-262 (1972), pp. 397-417] proposed that this results from reflections within the head, and thus that interpulse interval (IPI) is an indicator of head length, and by extrapolation, total length. For this idea to hold, IPIs must be stable within individuals, but differ systematically among individuals of different size. IPI stability was examined in photographically identified individuals recorded repeatedly over different dives, days, and years. IPI variation among dives in a single day and days in a single year was statistically significant, although small in magnitude (it would change total length estimates by <3%). As expected, IPIs varied significantly among individuals. Most individuals showed significant increases in IPIs over several years, suggesting growth. Mean total lengths calculated from published IPI regressions were 13.1 to 16.1 m, longer than photogrammetric estimates of the same whales (12.3 to 15.3 m). These discrepancies probably arise from the paucity of large (12-16 m) whales in data used in published regressions. A new regression is offered for this size range.

  4. Stability-indicating High-performance Liquid Chromatography Method for Simultaneous Determination of Aminophylline and Chlorpheniramine Maleate in Pharmaceutical Formulations.

    PubMed

    Ali, A; Ahmed, M; Mahmud, T; Qadir, M A; Nadeem, K; Saleem, A

    2015-01-01

    The present work deals with the development and validation of method for simultaneous determination of antihistaminic drugs in pharmaceutical formulations. A precise, specific and accurate reverse phase-high-performance liquid chromatography method for the simultaneous measurement of aminophylline and chlorpheniramine maleate was developed. The separation of drugs was achieved on C-18 (5 μm, 250×4.6 mm) high-performance liquid chromatography column. The runtime for analysis was 10 min. Mobile phase is mixture containing dilute H2SO4:methanol (60:40% v/v) with flow rate adjusted at 1.5 ml/min. The detection of components was performed at a wavelength of 264 nm. Retention times of aminophylline and chlorphinramine maleate were found to be 2.00 and 3.25 min, respectively. Linearity was found in the range of 16-24 μg/ml for chlorpheniramine maleate and 102.4-153.6 μg/ml for aminophylline with a correlation coefficient of 0.9998 and 0.9996, respectively. High peak purity index of 99.99% indicated the complete separation of analytes in the presence of degradation products is justification of method stability. Linearity, accuracy, specificity, precision and robustness studies were performed for method validation.

  5. Development and Validation of a Stability-Indicating Liquid Chromatographic Method for Estimating Olmesartan Medoxomil Using Quality by Design.

    PubMed

    Beg, Sarwar; Sharma, Gajanand; Katare, O P; Lohan, Shikha; Singh, Bhupinder

    2015-08-01

    The current studies entail systematic quality by design (QbD)-based development of a simple, rapid, sensitive and cost-effective stability-indicating method for the estimation of olmesartan medoxomil. Quality target method profile was defined and critical analytical attributes (CAAs) for the reverse-phase liquid chromatography method earmarked. Chromatographic separation accomplished on a C18 column using acetonitrile and water (containing 0.1% orthophosphoric acid, pH 3.5) in 40 : 60 (v/v) as mobile phase at a flow rate of 1.0 mL/min with UV detection at 243 nm. Risk assessment studies and screening studies facilitated comprehensive understanding of the factors affecting CAAs. The mobile phase ratio and flow rate were identified as critical method parameters (CMPs) and were systematically optimized using face-centered cubic design, evaluating for CAAs, namely peak area, retention time, theoretical plates and peak tailing. Statistical modelization was accomplished followed by response surface analysis for comprehending plausible interaction(s) among CMPs. Search for optimum solution was conducted through numerical and graphical optimization for demarcating the design space. Analytical method validation and subsequent forced degradation studies corroborated the method to be highly efficient for routine analysis of drug and its degradation products. The studies successfully demonstrate the utility of QbD approach for developing the highly sensitive liquid chromatographic method with enhanced method performance.

  6. Stability-indicating LC-UV method for the determination of eszopiclone and degradation impurities in tablet dosage form.

    PubMed

    Shaikh, Kabeer; Patil, Ashish; Gite, Sandeep

    2014-04-01

    A sensitive, stability-indicating reversed-phase high-performance liquid chromatographic method was developed for the determination of eszopiclone and related impurities in tablet dosage form. The chromatographic separation was achieved on an Inertsil C18 column (250 × 4.6 mm, 5 µm), using a mobile phase consisting of 0.05M monobasic sodium phosphate buffer containing 0.8% sodium lauryl sulfate (pH 3.5) and acetonitrile in the ratio of 60:40 (v/v), at a flow rate of 1.5 mL/min and temperature of 40°C. Quantification was achieved with photodiode array detection at 303 nm. The described method showed excellent linearity over a range of limits of quantification to 4.8 µg/mL (150% of specification limit; i.e., 3.2 µg/mL). The drug product was subjected to the stress conditions of oxidative, acid, base, thermal and photolytic degradation. Eszopiclone degradation was observed in acid hydrolysis, base hydrolysis and peroxide stress conditions. Eszopiclone was stable in thermal and photolytic degradation conditions. The developed method is simple, selective and accurate for the quantification of impurities and degradation products of eszopiclone in tablet dosage form.

  7. Validated stability-indicating HPLC method for the determination of mesna in presence of its degradation products.

    PubMed

    Rizk, Mohamed; Taha, Elham A; Mowaka, Shereen; Abdallah, Youmna M

    2015-01-01

    A rapid and simple stability-indicating liquid chromatographic method was developed and validated for analysis of mesna in the presence of its degradation products in drug substance and drug products in a run time not >5 min. The separation was achieved on a RP amide C16 column at room temperature using methanol-phosphate buffer (10:90, v/v, pH 3.0) as mobile phase at a flow rate of 1 mL min(-1) and UV detection at 210 nm. The detector response for mesna was linear over the selected concentration range from 50 to 1000 µg mL(-1) with a correlation coefficient 0.9998. The limit of detection and the limit of quantitation were 7.5 and 22.7 µg mL(-1), respectively. The solution was stable for at least 5 days. Baseline resolution between mesna and its degradation products was achieved. Diode array detection peak purity tests showed no peak interfered with mesna peak. Moreover, the method was successfully applied for the determination of mesna in two different commercially available drug products.

  8. High-performance liquid chromatographic stability indicating assay method of tianeptine sodium with simultaneous fluorescence and UV detection.

    PubMed

    Khedr, Alaa

    2007-07-01

    The purpose of this work is to develop a sensitive, selective, and validated stability-indicating HPLC assay of tianeptine (TIA) in bulk drug and tablet form. TIA is subjected to different stress conditions, including UV-light, oxidation, acid base-base hydrolysis, and temperature. TIA and its possible degradation products are analyzed on Agilent-Zorbax-XDB-C18 column using gradient elution with acetonitrile and 0.02M sodium acetate (pH 4.2). The samples are monitored simultaneously with photo-diode array at 254 nm and fluoroscence detector set to 350 nm (ex) and 425 nm (em). TIA is integrated from its UV-chromatogram, and the photodecomposition products are integrated from the fluoroscence-chromatogram. TIA and its photodecomposition products are separated by TLC using ethyl acetate-n-hexane-glacial acetic acid-methanol (10.0:14.0:0.2:1.0, v/v) as developing system. One potential photodegradation product is detected by fluoroscence in TIA-tablet form and separated by TLC. The linear range of TIA is between 0.5 to 50 microg/injection with limits of quantitation and detection values of 30 and 8 ng/injection, respectively. The inter-assay percentage of deviation is not more than 0.03%, and the day-to-day variation is not more than 0.1%.

  9. Quantification of halobetasol propionate and its impurities present in topical dosage forms by stability-indicating LC method.

    PubMed

    Nalwade, Santaji; Reddy, Vangala Ranga; Kulkarni, Dipak; Todamal, Sandip

    2015-01-01

    A novel, sensitive, stability-indicating, gradient, reverse-phase high-performance liquid chromatographic method has been developed for quantitative determination of halobetasol propionate and its impurities in topical dosage forms. The chromatographic separation was achieved on a Phenomenex Synergi polar reverse phase, 250 × 4.6 mm, 4 µm column. Mobile phase A comprises a mixture of 0.01 M KH2PO4 buffer containing 0.2% 1-octane sulfonic acid sodium salt (pH 3.0), acetonitrile and methanol in the ratio 80:15:05 (v/v/v), respectively, and mobile phase B contains a mixture of 0.01 M KH2PO4 buffer containing 0.2% 1-octane sulfonic acid sodium salt (pH 3.0), acetonitrile and methanol in the ratio 20:70:10 (v/v/v), respectively. The flow rate is 0.8 mL min(-1). The column compartment temperature is set at 40°C and the detection wavelength is set at 240 nm. The resolutions between Halobetasol propionate and all the impurities are >2.0 for all pairs of compounds. The drug product was subjected to International Conference on Harmonization (ICH)-prescribed hydrolytic, oxidative, photolytic and thermal stress conditions. The method is validated as per the ICH guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision, robustness and ruggedness.

  10. Validation of a stability-indicating RP-LC method for the determination of tigecycline in lyophilized powder.

    PubMed

    da Silva, Lucélia Magalhães; Salgado, Hérida Regina Nunes

    2013-02-01

    A reversed-phase liquid chromatography (RP-LC) method was validated for the determination of tigecycline in lyophilized powder. The LC method was conducted on a Luna C18 column (250 × 4.6 mm i.d.), maintained at room temperature. The mobile phase consisted of buffer containing sodium phosphate monobasic (0.015M) and oxalic acid (0.015M) (pH 7.0)-acetonitrile (75:25, v/v), run at a flow rate of 1.0 mL/min and using ultraviolet detection at 280 nm. The chromatographic separation was obtained with a retention time of 8.6 min, and was linear in the range of 40-100 µg/mL (r(2) = 0.9997). The specificity and stability-indicating capability of the method was proven through forced degradation studies, which also showed no interference of the excipients. The accuracy was 99.01% with a bias lower than 1.81%. The limits of detection and quantitation were 1.67 and 5.05 µg/mL, respectively. Moreover, method validation demonstrated satisfactory results for precision and robustness. The proposed method was applied for the analysis of the lyophilized powder formulation, contributing to improve the quality control and to assure the therapeutic efficacy.

  11. Development and validation of a stability-indicating liquid chromatography method for the determination of dabigatran etexilate in capsules.

    PubMed

    Bernardi, Raquel M; Fröehlich, Pedro E; Bergold, Ana M

    2013-01-01

    An RP-LC method was developed and validated for the determination of dabigatran etexilate in a capsule formulation. The LC method was carried out on a Zorbax C18 column (250 x 4.6 mm id). The mobile phase consisted of acetonitrile and a solution of triethylamine 0.1%, pH 6.0 adjusted with phosphoric acid (65 + 35, v/v) at a flow rate of 1.0 mL/min. The diode array detector was set at 225 nm. The chromatographic separation was obtained with retention time of 6.31 min, and linearity was in the range of 10-70 microg/mL (R2 = 0.9991). The specificity and stability-indicating capability of the method was proven through degradation studies and showing that there was no interference from the excipients. The accuracy was 100.23%, with an RSD of 1.34%. The LOD and LOQ were 0.04 and 10 microg/mL, respectively. Moreover, method validation demonstrated acceptable results for robustness and a system suitability test. The proposed method was applied for the analysis of the capsules to ensure their therapeutic efficacy.

  12. A new strategy to stabilize oxytocin in aqueous solutions: I. The effects of divalent metal ions and citrate buffer.

    PubMed

    Avanti, Christina; Amorij, Jean-Pierre; Setyaningsih, Dewi; Hawe, Andrea; Jiskoot, Wim; Visser, Jan; Kedrov, Alexej; Driessen, Arnold J M; Hinrichs, Wouter L J; Frijlink, Henderik W

    2011-06-01

    In the current study, the effect of metal ions in combination with buffers (citrate, acetate, pH 4.5) on the stability of aqueous solutions of oxytocin was investigated. Both monovalent metal ions (Na(+) and K(+)) and divalent metal ions (Ca(2+), Mg(2+), and Zn(2+)) were tested all as chloride salts. The effect of combinations of buffers and metal ions on the stability of aqueous oxytocin solutions was determined by RP-HPLC and HP-SEC after 4 weeks of storage at either 4°C or 55°C. Addition of sodium or potassium ions to acetate- or citrate-buffered solutions did not increase stability, nor did the addition of divalent metal ions to acetate buffer. However, the stability of aqueous oxytocin in aqueous formulations was improved in the presence of 5 and 10 mM citrate buffer in combination with at least 2 mM CaCl(2), MgCl(2), or ZnCl(2) and depended on the divalent metal ion concentration. Isothermal titration calorimetric measurements were predictive for the stabilization effects observed during the stability study. Formulations in citrate buffer that had an improved stability displayed a strong interaction between oxytocin and Ca(2+), Mg(2+), or Zn(2+), while formulations in acetate buffer did not. In conclusion, our study shows that divalent metal ions in combination with citrate buffer strongly improved the stability of oxytocin in aqueous solutions.

  13. Stability indicating spectrophotometric and spectrodensitometric methods for the determination of diatrizoate sodium in presence of its degradation product

    NASA Astrophysics Data System (ADS)

    Abd El-Rahman, Mohamed K.; Riad, Safaa M.; Abdel Gawad, Sherif A.; Fawaz, Esraa M.; Shehata, Mostafa A.

    2015-02-01

    Three sensitive, selective, and precise stability indicating methods for the determination of the X-ray contrast agent, diatrizoate sodium (DTA), in the presence of its acidic degradation product (highly cytotoxic 3,5 diamino metabolite) and in pharmaceutical formulation were developed and validated. The first method is a first derivative (D1) spectrophotometric one, which allows the determination of DTA in the presence of its degradate at 231.2 nm (corresponding to zero crossing of the degradate) over a concentration range of 2-24 μg/mL with mean percentage recovery 99.95 ± 0.97%. The second method is the first derivative of the ratio spectra (DD1) by measuring the peak amplitude at 227 nm over the same concentration range as D1 spectrophotometric method, with mean percentage recovery 99.99 ± 1.15%. The third method is a TLC-densitometric one, where DTA was separated from its degradate on silica gel plates using chloroform:methanol:ammonium hydroxide (20:10:2 by volume) as a developing system. This method depends on quantitative densitometric evaluation of thin layer chromatogram of DTA at 238 nm over a concentration range of 4-20 μg/spot, with mean percentage recovery 99.88 ± 0.89%. The selectivity of the proposed methods was tested using laboratory-prepared mixtures. The proposed methods have been successfully applied to the analysis of DTA in pharmaceutical dosage forms without interference from other dosage form additives. The results were statistically compared with the official US pharmacopeial method. No significant difference for either accuracy or precision was observed.

  14. Stability indicating spectrophotometric and spectrodensitometric methods for the determination of diatrizoate sodium in presence of its degradation product.

    PubMed

    Abd El-Rahman, Mohamed K; Riad, Safaa M; Abdel Gawad, Sherif A; Fawaz, Esraa M; Shehata, Mostafa A

    2015-02-05

    Three sensitive, selective, and precise stability indicating methods for the determination of the X-ray contrast agent, diatrizoate sodium (DTA), in the presence of its acidic degradation product (highly cytotoxic 3,5 diamino metabolite) and in pharmaceutical formulation were developed and validated. The first method is a first derivative (D1) spectrophotometric one, which allows the determination of DTA in the presence of its degradate at 231.2 nm (corresponding to zero crossing of the degradate) over a concentration range of 2-24 μg/mL with mean percentage recovery 99.95±0.97%. The second method is the first derivative of the ratio spectra (DD1) by measuring the peak amplitude at 227 nm over the same concentration range as D1 spectrophotometric method, with mean percentage recovery 99.99±1.15%. The third method is a TLC-densitometric one, where DTA was separated from its degradate on silica gel plates using chloroform:methanol:ammonium hydroxide (20:10:2 by volume) as a developing system. This method depends on quantitative densitometric evaluation of thin layer chromatogram of DTA at 238 nm over a concentration range of 4-20 μg/spot, with mean percentage recovery 99.88±0.89%. The selectivity of the proposed methods was tested using laboratory-prepared mixtures. The proposed methods have been successfully applied to the analysis of DTA in pharmaceutical dosage forms without interference from other dosage form additives. The results were statistically compared with the official US pharmacopeial method. No significant difference for either accuracy or precision was observed.

  15. Determination of aliskiren in tablet dosage forms by a validated stability-indicating RP-LC method.

    PubMed

    Wrasse-Sangoi, M; Sangoi, M S; Oliveira, P R; Secretti, L T; Rolim, C M B

    2011-02-01

    A reversed-phase liquid chromatography (RP-LC) method is validated for the determination of aliskiren in tablet dosage form. The LC method is carried out on a Waters XBridge C(18) column (150 × 4.6 mm i.d.), maintained at 25°C. The mobile phase consisted of acetonitrile:water (95:5, v/v)/phosphoric acid (25 mM, pH 3.0) (40:60, v/v), run at a flow rate of 1.0 mL/min, with photodiode array detector set at 229 nm. The chromatographic separation is obtained with aliskiren retention time of 3.68 min, and it is linear in the range of 10-300 μg/mL (r = 0.9999). The limits of detection and quantitation are 2.38 and 7.93 μg/mL, respectively. The specificity and stability-indicating capability of the method are proven through degradation studies, which also showed that there is no interference of the formulation excipients, showing that peak is free from any coeluting peak. The method showed adequate precision, with a relative standard deviation (RSD) values lower than 0.92%. Good values of accuracy were also obtained, with a mean value of 99.55%. Experimental design is used during validation to calculate method robustness. The proposed method is applied for the analysis of the tablet dosage forms, contributing to improve the quality control and to assure the therapeutic efficacy.

  16. Stability-indicating methods for the determination of erdosteine in the presence of its acid degradation products.

    PubMed

    Moustafa, Nadia M; Badawey, Amr M; Lamie, Nesrine T; El-Aleem, Abd El-Aziz B Abd

    2014-01-01

    Four accurate, sensitive, and reproducible stability-indicating methods for the determination of erdosteine in the presence of its acid degradation products are presented. The first method involves processing the spectra by using a first-derivative method at 229 nm in a concentration range of 10-70 microg/mL. The mean percentage recovery was 100.43 +/- 0.977. The second method is based on ratio-spectra first derivative spectrophotometry at 227.4 and 255 nm over a concentration range of 10-70 microg/mL. The mean percentage recovery was 99.65 +/- 1.122% and 100.02 +/- 1.306% at 227.4 and 255 nm, respectively. The third method utilizes quantitative densitometric evaluation of the TLC of erdosteine in the presence of its acid degradation products, and uses methanol-chloroform-ammonia (7 + 3 +/- 0.01, v/v/v) as the mobile phase. TLC chromatograms were scanned at 235 nm. This method analyzes erdosteine in a concentration range of 2.4-5.6 microg/spot, with a mean percentage recovery of 100.03 +/- 1.015%. The fourth method is HPLC for the simultaneous determination of erdosteine in the presence of its acid degradation products. The mobile phase consists of water-methanol (65 + 35, v/v). The standard curve of erdosteine showed good linearity over a concentration range of 10-80 microg/mL, with a mean percentage recovery of 99.90 +/- 1.207%. These methods were successfully applied to the determination of erdosteine in bulk powder, laboratory-prepared mixtures containing different percentages of the degradation products, and pharmaceutical dosage forms. The validity of results was assessed by applying the standard addition technique. The results obtained agreed statistically with those obtained by a reported method, showing no significant differences with respect to accuracy and precision.

  17. Application of spectrophotometric, densitometric, and HPLC techniques as stability indicating methods for determination of Zaleplon in pharmaceutical preparations

    NASA Astrophysics Data System (ADS)

    Metwally, Fadia H.; Abdelkawy, M.; Abdelwahab, Nada S.

    2007-12-01

    Spectrophotometric, spectrodensitometric and HPLC are stability indicating methods described for determination of Zaleplon in pure and dosage forms. As Zaleplon is easily degradable, the proposed techniques in this manuscript are adopted for its determination in presence of its alkaline degradation product, namely N-[4-(3-cyano-pyrazolo[1,5a]pyridin-7-yl)-phenyl]- N-ethyl-acetamide. These approaches are successfully applied to quantify Zaleplon using the information included in the absorption spectra of appropriate solutions. The second derivative (D 2) spectrophotometric method, allows determination of Zaleplon without interference of its degradate at 235.2 nm using 0.01N HCl as a solvent with obedience to Beer's law over a concentration range of 1-10 μg ml -1 with mean percentage recovery 100.24 ± 0.86%. The first derivative of the ratio spectra ( 1DD) based on the simultaneous use of ( 1DD) and measurement at 241.8 nm using the same solvent and over the same concentration range as (D 2) spectrophotometric method, with mean percentage recovery 99.9 ± 1.07%. The spectrodensitometric analysis allows the separation and quantitation of Zaleplon from its degradate on silica gel plates using chloroform:acetone:ammonia solution (9:1:0.2 by volume) as a mobile phase. This method depends on quantitave densitometric evaluation of thin layer chromatogram of Zaleplon at 338 nm over a concentration range of 0.2-1 μg band -1, with mean percentage recovery 99.73 ± 1.35. Also a reversed-phase liquid chromatographic method using 5-C8 (22 cm × 4.6 mm i.d. 5 μm particle size) column was described and validated for quantitation of Zaleplon using acetonitrile:deionised water (35:65, v/v) as a mobile phase using Paracetamol as internal standard and a flow rate of 1.5 ml min -1 with UV detection of the effluent at 232 nm at ambient temperature over a concentration range of 2-20 μg ml -1 with mean percentage recovery 100.19 ± 1.15%. The insignificance difference of the proposed

  18. Pharmacokinetic study of arctigenin in rat plasma and organ tissue by RP-HPLC method.

    PubMed

    He, Fan; Dou, De-Qiang; Hou, Qiang; Sun, Yu; Kang, Ting-Guo

    2013-01-01

    A high-performance liquid chromatography (HPLC) technique was developed for the determination of arctigenin in plasma and various organs of rats after the oral administration of 30, 50 and 70 mgkg(-1) of arctigenin to the Sprague-Dawley rats. Results showed that the validated HPLC method was simple, fast, reproducible and suitable to the determination of arctigenin in rat plasma and organ tissue and one-compartmental model with zero-order absorption process can well describe the changes of arctigenin concentration in the plasma. The concentration of compound was highest in the spleen, less in the liver and the least in the lung.

  19. Sorption of certain isatins on various sorbents under RP-HPLC conditions

    NASA Astrophysics Data System (ADS)

    Konstantinov, A. V.; Shafigulin, R. V.; Il'in, M. M.; Davankov, V. A.; Bulanova, A. V.; Purygin, P. P.

    2013-06-01

    The results from chromatographic analysis of biologically active isatin derivatives on hyper-crosslinked polystyrene (HCLPS) and silica gel modified by octadecyl groups (SilC18) are presented. The constants of distribution of sorbates between a mobile phase and the investigated sorbents ( K x ) and the changes in the standard differential molar Gibbs energies of adsorption (Δ _a bar G^circ ) are calculated, along with the chromatographic retention-physicochemical property of sorbate dependences. It is found that the equations describing these dependences have high forecasting ability with respect to the values of retention factors of the investigated sorbates.

  20. Regularities of Anthocyanins Retention in RP HPLC for “Water–Acetonitrile–Phosphoric Acid” Mobile Phases

    PubMed Central

    Deineka, V. I.; Deineka, L. A.; Saenko, I. I.

    2015-01-01

    The influence of exchange of HCOOH (System 2) by phosphoric acid (System 1) for acidification of the “acetonitrile–water” mobile phases for reversed-phase HPLC of anthocyanins was investigated in the framework of relative retention analysis. The differences and similarities of anthocyanins separation were revealed. It has been shown that some common features of the quantitative relationships may be used for preliminary anthocyanins structure differentiation, according to the number of OH-groups in anthocyanidin backbone as well as to a number of saccharide molecules in glycoside radicals in position 3 of the anthocyanin without MS detection. PMID:25692073

  1. Simultaneous estimation of etoricoxib and thiocolchicoside by RP-HPLC method in combined dosage forms.

    PubMed

    Kumar, Sanjiv; Joshi, Amit; Thakur, Rahul Singh; Pathak, Anupam K; Shah, Kamal

    2011-01-01

    A simple, reproducible and efficient reverse phase high performance liquid chromatographic method was developed for simultaneous estimation of etoricoxib and thiocolchicoside in combined tablet dosage form. Formulation containing etoricoxib and thiocolchicoside is used as analgesic. Chromatography was performed on a 250 mm x 4.6 mm, 5-microm particle size, BDS Hypersil C-18 column with trifluoroacetic acid buffer (pH 2.6) and acetonitrile (75:25, v/v) as a mobile phase. The detection of the combined dosage form was carried out at 220 nm and a flow rate employed was 1.5 mL/min. The retention times were 6.6 and 3.1 min for etoricoxib and thiocolchicoside, respectively. Linearity was obtained in the concentration range 20 to 160 ppm for etoricoxib and in the range 2 to 16 ppm for thiocolchicoside with a correlation coefficient of 0.9918 and 0.9994, respectively. The results of the analysis were validated statistically and recovery studies confirmed the accuracy and precision of the proposed method.

  2. Quantitation of buclizine hydrochloride in pharmaceutical formulations and human serum by RP-HPLC.

    PubMed

    Arayne, M Saeed; Sultana, Najma; Siddiqui, Farhan Ahmed

    2006-10-01

    An isocratic reversed phase high-performance liquid chromatographic (HPLC) method with ultraviolet detection at 230 nm has been developed for the determination of buclizine hydrochloride in human serum and dosage formulation. Methylparaben was successfully used as an internal standard. Good chromatographic separation between buclizine and internal standard peaks was achieved by using a stainless steel analytical column Nucleosil, C18 (10 microm, 25 cm x 0.46 cm). The system was operated at room temperature using a mobile phase consisting of acetonitrile-water (1:1) (pH 2.6) with phosphoric acid 85% at a flow rate of 2 ml/min. The calibration curve for buclizine hydrochloride in human serum was linear over the tested concentration range of 10, 3, 1.5, 0.5, 0.15, 0.05, and 0.025 microg/ml with a correlation coefficient of 0.9999. The intra- and inter-run precision and accuracy results were 98.07 to 100.34. The proposed method was validated for selectivity, linearity, accuracy, and precision. The method was found to be suitable for the quality control of buclizine hydrochloride in bulk drug as well as in human serum.

  3. Quantification of Aconitum alkaloids in aconite roots by a modified RP-HPLC method.

    PubMed

    Jiang, Zhi-Hong; Xie, Ying; Zhou, Hua; Wang, Jing-Rong; Liu, Zhong-Qiu; Wong, Yuen-Fan; Cai, Xiong; Xu, Hong-Xi; Liu, Liang

    2005-01-01

    The three Aconitum alkaloids, aconitine (1), mesaconitine (2) and hypaconitine (3), are pharmacologically active but also highly toxic. A standardised method is needed for assessing the levels of these alkaloids in aconite roots in order to ensure the safe use of these plant materials as medicinal herbs. By optimising extraction, separation and measurement conditions, a reliable, reproducible and accurate method for the quantitative determination of all three Aconitum alkaloids in unprocessed and processed aconite roots has been developed. This method should be appropriate for use in the quality control of Aconitum products. The three Aconitum alkaloids were separated by a modified HPLC method employing a C18 column gradient eluted with acetonitrile and ammonium bicarbonate buffer. Quantification of Aconitum alkaloids, detected at 240 nm, in different batches of samples showed that the content of 1, 2 and 3 varied significantly. In general, the alkaloid content of unprocessed roots was higher than that of processed roots. These variations were considered to be the result of differences in species, processing methods and places of origin of the samples.

  4. Simultaneous determination of betulin and betulinic acid in white birch bark using RP-HPLC.

    PubMed

    Zhao, Guoling; Yan, Weidong; Cao, Dan

    2007-02-19

    A simple procedure is described for the simultaneous extraction and determination of betulin and betulinic acid in white birch bark. The extraction was checked using different solvents: dichloromethane, ethyl acetate, acetone, chloroform, methanol and 95% ethanol (aqueous solution, v/v). It was found 95% ethanol was a good extraction solvent that allowed extraction of triterpenoid with a highest content. Separation was achieved on a reversed phase C(18) column with acetonitrile-water 86:14 (v/v). Detection was accomplished with UV detection at lambda=210 nm. Using this method, the bioactive triterpenoid in white birch bark were simultaneously determined. Significant variations in the content of betulin and betulinic acid in white birch bark growing in different locations of China were also observed.

  5. A new total antioxidant potential measurements using RP-HPLC assay with fluorescence detection.

    PubMed

    Głód, Bronisław K; Piszcz, Paweł; Czajka, Katarzyna; Zarzycki, Paweł K

    2011-05-01

    In this paper, an improved total antioxidant potential (TAP) estimation using high-performance liquid chromatographic (HPLC) assay with fluorometric detection has been described. The principle of this method is based on the hydroxyl radicals generated in the Fenton-like reaction and subsequently detected using hydroxyterephthalic acid (HTPA), which is a reaction product of hydroxyl radicals and terephthalic acid (TPA), working as a sensing compound. HTPA quantity in the samples was measured by fluorescence detector working at excitation and emission wavelengths equal to 312 and 428 nm, respectively. A number of key experimental conditions including the influence of the reaction (incubation) time on the surface areas of HTPA peaks, concentration of Fe(II) ions as well as the influence of concentration of TPA on the surface area of the chromatographic peak of HTPA were optimized to the characteristic feature of TAP measurements. The elaborated assay has been used to evaluate TAP values of selected low-molecular mass compounds like pyrogallol, tryptamine, and n-alcohols (methanol, ethanol, and n-propanol) as well as chlorogenic and ascorbic acids and benzoic acid derivatives, which are commonly present in the food samples.

  6. A Sensitive RP-HPLC Method for Simultaneous Estimation of Diethylcarbamazine and Levocetirizine in Tablet Formulation.

    PubMed

    Reddy, J Mahesh; Jeyaprakash, M R; Madhuri, K; Meyyanathan, S N; Elango, K

    2011-05-01

    A simple, sensitive and reproducible method was developed and validated for the simultaneous estimation of diethylcarbamazine and levocetirizine in its tablet formulation by reverse phase high performance liquid chromatography using Waters1515 HPLC with UV detector at the λ(max) of 224 nm, using Princeton Sphere-100 C(18) (250×4.6 mm. 5 μ) column. The mobile phase used was 20mM potassium dihydrogen orthophosphate buffer (pH: 3.2):acetonitrile (50:50 v/v) with isocratic flow (flow rate 1 ml/min) and the pH was adjusted with orthophosphoric acid. Losartan potassium was used as an internal standard. The compounds diethylcarbamazine, levocetirizine and losartan potassium were eluted at 2.12, 4.27 and 5.96 min, respectively. The peaks were eluted with better resolution. The method was accurate with assay values of 96.32 and 93.04% w/w, precise (%RSD) with intra-day 1.72 and 1.89 and inter-day 1.85 and 1.92, recoveries 102.86 and 101.1% w/w, which are very sensitive with limit of detections (LOD)'s 75, 50 ng/ml and limit of quantification (LOQ)'s 100, 75 ng/ml and linear with R(2) values 0.994 in the range of 5 to 30 μg/ml 0.1 to 1 μg/ml for diethylcarbamazine and levocetirizine, respectively. Hence this method can be applied for quantification of different formulations containing diethylcarbamazine and levocetirizine simultaneously.

  7. Isolation, Identification, and Characterisation of Degradation Products and the Development and Validation of a Stability-Indicating Method for the Estimation of Impurities in the Tolterodine Tartrate Formulation.

    PubMed

    Prakash, Lakkireddy; Himaja, Malipeddi; Vasudev, Rudraraju

    2015-01-01

    A short and sensitive stability-indicating gradient RP-UPLC method was developed for the quantitative determination of process-related impurities and degradation products of tolterodine tartrate in pharmaceutical formulations. The method was developed by using the Waters ACQUITY UPLC™ BEH shield RP18 (2.1 × 100 mm, 1.7 μm) column with a mobile phase containing a gradient mixture of solvent A and B at a detection wavelength of 210 nm. During the stress study, the degradation products of tolterodine tartrate were well-resolved from tolterodine and its impurities and the mass balances were found to be satisfactory in all the stress conditions, thus proving the stability-indicating capability of the method. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection and quantification, accuracy, precision, ruggedness, and robustness. During the stability (40°C/75% RH, 3 months) analysis of the drug product, one unknown impurity was detected by the above stability-indicating method. The unknown impurity was isolated by preparative HPLC and subjected to mass and NMR studies. Based on the spectral data, the unknown impurity was characterised as 2-(3-amino-1-phenylpropyl)-4-methylphenol (des-N,N-diisopropyl tolterodine). Structural elucidation of the impurity by spectral data is discussed in detail.

  8. Validation of a high performance liquid chromatography method for the stabilization of epigallocatechin gallate.

    PubMed

    Fangueiro, Joana F; Parra, Alexander; Silva, Amélia M; Egea, Maria A; Souto, Eliana B; Garcia, Maria L; Calpena, Ana C

    2014-11-20

    Epigallocatechin gallate (EGCG) is a green tea catechin with potential health benefits, such as anti-oxidant, anti-carcinogenic and anti-inflammatory effects. In general, EGCG is highly susceptible to degradation, therefore presenting stability problems. The present paper was focused on the study of EGCG stability in HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid) medium regarding the pH dependency, storage temperature and in the presence of ascorbic acid a reducing agent. The evaluation of EGCG in HEPES buffer has demonstrated that this molecule is not able of maintaining its physicochemical properties and potential beneficial effects, since it is partially or completely degraded, depending on the EGCG concentration. The storage temperature of EGCG most suitable to maintain its structure was shown to be the lower values (4 or -20 °C). The pH 3.5 was able to provide greater stability than pH 7.4. However, the presence of a reducing agent (i.e., ascorbic acid) was shown to provide greater protection against degradation of EGCG. A validation method based on RP-HPLC with UV-vis detection was carried out for two media: water and a biocompatible physiological medium composed of Transcutol®P, ethanol and ascorbic acid. The quantification of EGCG for purposes, using pure EGCG, requires a validated HPLC method which could be possible to apply in pharmacokinetic and pharmacodynamics studies.

  9. Chromium Oxidation State in Planetary Basalts: Oxygen Fugacity Indicator and Critical Variable for Cr-Spinel Stability

    NASA Technical Reports Server (NTRS)

    Bell, A. S.; Burger, P. V.; Le, Loan; Papike, J. J.; Jone, J.; Shearer, C. K.

    2014-01-01

    Cr is a ubiquitous and relatively abundant minor element in basaltic, planetary magmas. At the reduced oxidation states (stability and Cr concentration of magmatic phases such as spinel, clinopyroxene, and olivine. However, understanding the Cr valence in quenched melts has historically been plagued with analytical issues, and only recently has reliable methodology for quantifying Cr valence in quenched melts been developed. Despite this substantial difficulty, the pioneering works of Hanson and Jones and Berry and O'Neill provided important insights into the oxidation state of Cr in in silicate melts. Here we present a series of 1-bar gas mixing experiments performed with a Fe-rich basaltic melt in which have determined the Cr redox ratio of the melt at over a range of fO2 values by measuring this quantity in olivine with X-ray Absorption Near Edge Spectroscopy (XANES). The measured Cr redox ratio of the olivine phenocrysts can be readily converted to the ratio present in the conjugate melt via the ratio of crystal-liquid partition coefficients for Cr3+ and Cr2+. We have applied these results to modeling Cr spinel stability and Cr redox ratios in a primitive, iron-rich martian basalt.

  10. Granulocyte-macrophage colony stimulating factor: Evaluation of biopharmaceutical formulations by stability-indicating RP-LC method and bioassay.

    PubMed

    Leal, Diogo Paim; Souto, Ricardo Bizogne; Schutkoski, Renato; Bergamo, Ana Cláudia; Dalmora, Sérgio Luiz

    2011-07-01

    The granulocyte-macrophage colony stimulating factor (GM-CSF) is a cytokine that regulates the proliferation and differentiation of hematopoietic cells and activates granulocytes and macrophages. A reversed-phase liquid chromatography (RP-LC) method was validated for the assessing of the stability of non-glycosylated recombinant rhGM-CSF (Molgramostim) in biopharmaceutical formulations. The RP-LC method was carried out on a Jupiter C(4) column (250 mm × 4.6 mm i.d.), maintained at 45 °C. The mobile phase A consisted of 0.1% TFA and the mobile phase B was acetonitrile with 0.1% TFA in acetonitrile, run at a flow rate of 1 mL/min, and using photodiode array (PDA) detection at 214 nm. Chromatographic separation was obtained with a retention time of 29.2 min, and was linear over the concentration range of 2-300 μg/mL (r(2) = 0.9992). Specificity was established in degradation studies. Moreover, the in vitro cytotoxicity test of the degraded products showed significant differences (p < 0.05). The method was applied to the assessment of rhGM-CSF and related proteins in biopharmaceutical dosage forms, and the results were correlated to those of a bioassay. It is concluded that the employment of RP-LC in conjunction with current methods allows a great improvement in monitoring stability, quality control and thereby assures the therapeutic efficacy.

  11. A Fast, Stability-Indicating, and Validated Liquid Chromatography Method for the Purity Control of Lercanidipine Hydrochloride in Tablet Dosage Form

    PubMed Central

    Mehta, Saumil; Singh, Sukhdev; Chikhalia, Kishor

    2014-01-01

    A robust, sensitive, and stability-indicating rapid resolution liquid chromatography method for the simultaneous determination of process impurities and degradation products of lercanidipine hydrochloride in pharmaceutical dosage form was developed and validated. The chromatographic separation was performed on the Zorbax SB C18 [(50 × 4.6) mm] 1.8 μm column, using gradient elution of a potassium dihydrogen phosphate buffer (pH 3.5, 0.01 M) and acetonitrile. The flow rate was 1.0 ml/min and UV detection was performed at 220 nm. The method was further evaluated for its stability-indicating capability by hydrolytic, oxidative, thermal, thermal with moisture, and photolytic degradation studies. All acceptance criteria of the International Conference on Harmonization guidelines for validation were covered in the method validation. This method can be used for purity control during manufacture and real time stability studies. A shorter run time of 10 minutes and good solution stability for at least 48 hours allowed the quantification of more than 50 samples per day with comparatively lower costs than existing methods. PMID:24959405

  12. Stability-indicating spectrophotometric methods for determination of the anticoagulant drug apixaban in the presence of its hydrolytic degradation product.

    PubMed

    Tantawy, Mahmoud A; El-Ragehy, Nariman A; Hassan, Nagiba Y; Abdelkawy, Mohamed

    2016-04-15

    Apixaban (a novel anticoagulant agent) was subjected to a stress stability study including acid, alkali, oxidative, photolytic, and thermal degradation. The drug was found to be only liable to acidic and alkaline hydrolysis. The degradation product was then isolated and identified by IR and GC-mass spectrometry. Four spectrophotometric methods, namely; first derivative (D(1)), derivative ratio (DR), ratio difference (RD) and mean centering of ratio spectra (MCR), have been suggested for the determination of apixaban in presence of its hydrolytic degradation product. The proposed methods do not require any preliminary separation step. The accuracy, precision and linearity ranges of the proposed methods were determined, and the methods were validated as per ICH guidelines and the specificity was assessed by analyzing synthetic mixtures containing different percentages of the degradation product with the drug. The developed methods were successfully applied for the determination of apixaban in bulk powder and its tablet dosage form.

  13. Integrated Community Profiling Indicates Long-Term Temporal Stability of the Predominant Faecal Microbiota in Captive Cheetahs

    PubMed Central

    Becker, Anne A. M. J.; Janssens, Geert P. J.; Snauwaert, Cindy; Hesta, Myriam; Huys, Geert

    2015-01-01

    Understanding the symbiotic relationship between gut microbes and their animal host requires characterization of the core microbiota across populations and in time. Especially in captive populations of endangered wildlife species such as the cheetah (Acinonyx jubatus), this knowledge is a key element to enhance feeding strategies and reduce gastrointestinal disorders. In order to investigate the temporal stability of the intestinal microbiota in cheetahs under human care, we conducted a longitudinal study over a 3-year period with bimonthly faecal sampling of 5 cheetahs housed in two European zoos. For this purpose, an integrated 16S rRNA DGGE-clone library approach was used in combination with a series of real-time PCR assays. Our findings disclosed a stable faecal microbiota, beyond intestinal community variations that were detected between zoo sample sets or between animals. The core of this microbiota was dominated by members of Clostridium clusters I, XI and XIVa, with mean concentrations ranging from 7.5-9.2 log10 CFU/g faeces and with significant positive correlations between these clusters (P<0.05), and by Lactobacillaceae. Moving window analysis of DGGE profiles revealed 23.3-25.6% change between consecutive samples for four of the cheetahs. The fifth animal in the study suffered from intermediate episodes of vomiting and diarrhea during the monitoring period and exhibited remarkably more change (39.4%). This observation may reflect the temporary impact of perturbations such as the animal’s compromised health, antibiotic administration or a combination thereof, which temporarily altered the relative proportions of Clostridium clusters I and XIVa. In conclusion, this first long-term monitoring study of the faecal microbiota in feline strict carnivores not only reveals a remarkable compositional stability of this ecosystem, but also shows a qualitative and quantitative similarity in a defined set of faecal bacterial lineages across the five animals under

  14. Integrated community profiling indicates long-term temporal stability of the predominant faecal microbiota in captive cheetahs.

    PubMed

    Becker, Anne A M J; Janssens, Geert P J; Snauwaert, Cindy; Hesta, Myriam; Huys, Geert

    2015-01-01

    Understanding the symbiotic relationship between gut microbes and their animal host requires characterization of the core microbiota across populations and in time. Especially in captive populations of endangered wildlife species such as the cheetah (Acinonyx jubatus), this knowledge is a key element to enhance feeding strategies and reduce gastrointestinal disorders. In order to investigate the temporal stability of the intestinal microbiota in cheetahs under human care, we conducted a longitudinal study over a 3-year period with bimonthly faecal sampling of 5 cheetahs housed in two European zoos. For this purpose, an integrated 16S rRNA DGGE-clone library approach was used in combination with a series of real-time PCR assays. Our findings disclosed a stable faecal microbiota, beyond intestinal community variations that were detected between zoo sample sets or between animals. The core of this microbiota was dominated by members of Clostridium clusters I, XI and XIVa, with mean concentrations ranging from 7.5-9.2 log10 CFU/g faeces and with significant positive correlations between these clusters (P<0.05), and by Lactobacillaceae. Moving window analysis of DGGE profiles revealed 23.3-25.6% change between consecutive samples for four of the cheetahs. The fifth animal in the study suffered from intermediate episodes of vomiting and diarrhea during the monitoring period and exhibited remarkably more change (39.4%). This observation may reflect the temporary impact of perturbations such as the animal's compromised health, antibiotic administration or a combination thereof, which temporarily altered the relative proportions of Clostridium clusters I and XIVa. In conclusion, this first long-term monitoring study of the faecal microbiota in feline strict carnivores not only reveals a remarkable compositional stability of this ecosystem, but also shows a qualitative and quantitative similarity in a defined set of faecal bacterial lineages across the five animals under

  15. A Novel, Rapid, and Validated Stability-Indicating UPLC Method for the Estimation of Drotaverine Hydrochloride and Ibuprofen Impurities in Oral Solid Dosage Form

    PubMed Central

    Vijay Kumar, Rekulapally; Rao, Vinay U.; Anil Kumar, N.; Venkata Subbaiah, B.

    2015-01-01

    A novel, stability-indicating, reversed-phase ultra-performance liquid chromatographic (RP-UPLC) method was developed for the determination of pure drotaverine hydrochloride and ibuprofen in the presence of their impurities and degradation products. The method was developed using a Waters UPLC BEH C18, 100 × 2.1 mm, 1.7 µm column with a flow rate of 0.3 mL/min and detector wavelength at 210 nm. The mobile phase consisted of potassium dihydrogen orthophosphate buffer and acetonitrile. Drotaverine hydrochloride and ibuprofen were subjected to the stress conditions of oxidative, acid, base, photolytic, and thermal degradation. Degradation products resulting from the stress studies were well-resolved, thus confirming the test method as stability-indicating. Validation of the method was carried out as per International Conference on Harmonization guidelines. PMID:26839839

  16. Stability-indicating high-performance thin-layer chromatographic method for analysis of itraconazole in bulk drug and in pharmaceutical dosage form

    PubMed Central

    Parikh, Shalin K.; Dave, Jayant B.; Patel, Chhagan N.; Ramalingan, Badmanaban

    2011-01-01

    Background: A new, simple, selective, precise, and stability-indicating high-performance thin-layer chromatographic method has been established for analysis of itraconazole (ITZ) in the bulk drug and in pharmaceutical formulations. Separation was achieved on aluminium plate precoated with silica gel 60F254 using Toluene : Chloroform : Methanol [5 : 5 : 1.5 (v/v)] as mobile phase. Densitometric analysis was performed at 260 nm. Result: Compact bands of ITZ were obtained at Rf 0.52 ± 0.02. Linearity (R2 = 0.9978), limit of detection (180.29 ng/band), limit of quantification (546.34 ng/band), recovery (98–102%), and precision (≤0.51%) were satisfactory. Drug was not degraded under neutral and alkaline hydrolysis, UV and photolytic degradation, under-elevated temperature, and humidity. ITZ is degraded under acidic hydrolysis and oxidative condition; the degraded products were well resolved from individual bulk drug response. Developed method can effectively resolve drug from its excipients in capsule dosage form. The specificity of the method was confirmed by peak purity of resolved peak. Conclusion: The method can be applicable for routine analysis of ITZ in pharmaceutical formulation as stability-indicating. Because the method can effectively separate the drug from its degradation products as well as excipients, it can be used as a stability-indicating method. PMID:23781436

  17. Development and validation of a stability-indicating high performance liquid chromatographic (HPLC) assay for biperiden in bulk form and pharmaceutical dosage forms.

    PubMed

    Mohammadi, A; Mehramizi, A; Moghaddam, F Aghaee; Jabarian, L Erfani; Pourfarzib, M; Kashani, H N

    2007-07-01

    Current compendial (USP) methods of assay for the analysis of biperiden in bulk form and pharmaceutical dosage forms involve the use of titrimetric and spectrophotometric procedures, respectively. These are non-selective and non-stability-indicating techniques. In this work, a stability-indicating high performance liquid chromatographic assay procedure has been developed and validated for biperiden. The liquid chromatographic separation was achieved isocratically on a symmetry C8 column (150 mm x 3.9 mm i.d., 5 microm particle size) using a mobile phase containing methanol-buffer (50:50, v/v, pH 2.50) at a flow rate of 1 ml/min and UV detection at 205 nm. The buffer was composed of sodium dihydrogen phosphate (50 mM) and 1-heptanesulfonic acid sodium salt (5 mM). The method was linear over the concentration range of 0.5-25 microg/ml (r=0.9998) with a limit of detection and quantitation 0.03 and 0.1 microg/ml, respectively. The method has the requisite accuracy, selectivity, sensitivity and precision to assay biperiden in bulk form and pharmaceutical dosage forms. Degradation products resulting from the stress studies did not interfere with the detection of biperiden and the assay is thus stability-indicating.

  18. Posture control development in children aged 2-7 years old, based on the changes of repeatability of the stability indices.

    PubMed

    Sobera, Małgorzata; Siedlecka, Bożena; Syczewska, Małgorzata

    2011-03-10

    One of the most common problems encountered in posture control studies is relatively poor repeatability of postural stability measures based on the COP (center of pressure) time-series which results from the inherent variability of postural control. The repeatability of the data reflecting the postural control mechanisms in young children is still not well enough explained. The differences between of the repeatability of the stability indices of left and right foot may reflect the lateralization development of legs in the support function. The aim of the present study was two-fold: the assessment of the repeatability of the stability indices in three consecutive trials in young children, aged 2-7 years old, during quiet bipedal stance and the description of process of lower limbs lateralization, based on the difference of repeatability of both feet stability the indices changing with years. The subjects were 272 young healthy children aged 2-7 years old separated in 6 groups for children of different age. Each child stood for around 90s on two AccuSway force platforms (AMTI). The shifts of COP beneath left and right legs were recorded onto a computer by using appropriate software compatible with platforms. The indices of the ellipse area and velocity COP shifts were calculated. For assessment of the repeatability the concordance correlation coefficient (CCC) of the indices was used between the 1st and 2nd, 2nd and 3rd, and 1st and 3rd trials. Young children of 2-4 years old exhibit low level of the stability indices repeatability which increases in 5-year-old children, 6-year-olds revealed both low and high and 7-year-olds good and high levels of repeatability. Youngest children showed higher repeatability of the ellipse area of the left leg, 3- and 4-year-olds the right leg, while 6-year-olds again the left leg. In 5- and 7-year-olds there were no differences in the repeatability of stability indices between the left and right foot. The comparisons of the

  19. The Stability of Rankings Derived from Composite Indicators: Analysis of the "IL Sole 24 Ore" Quality of Life Report

    ERIC Educational Resources Information Center

    Lun, G.; Holzer, D.; Tappeiner, G.; Tappeiner, U.

    2006-01-01

    The calculation of composite indicators and the derivation of respective rankings is a common method used to benchmark countries or regions. However, although the statistical robustness of these rankings is often criticised, they often still spark off heated political debate. Here, we assess the sensitivity of the province ranking published by the…

  20. Development and Validation of highly Sensitive Stability Indicating Spectrofluorimetric Method for Determination of Amlodipine in Pharmaceutical Preparations and Human Plasma.

    PubMed

    Mohamed, Abdel-Maaboud I; Omar, Mahmoud A; Hammad, Mohamed A; Mohamed, Abobakr A

    2016-11-01

    A highly sensitive and simple spectrofluorimetric method was developed for the determination of Amlodipine besylate (AML) in its pharmaceutical formulations and spiked human plasma. The proposed method is based on the investigation of the fluorescence spectral behaviour of AML in Tween-80 micellar system. In aqueous solution, the fluorescence intensity of AML was greatly enhanced (160 %) in the presence of Tween-80. The fluorescence intensity was measured at 427 nm after excitation at 385 nm. The fluorescence-concentration plot was rectilinear over the concentration range 0.1-4.0 μg/ml, with lower detection limit of 0.03 μg/ml. The suggested method was successfully applied for the analysis of AML in its commercial tablets alone or in combination with either Atorvastatin or Valsartan. The application of the proposed method was extended to the assay of AML in spiked human plasma and stability studies of AML after exposure to different forced degradation conditions, such as acidic, alkaline, photo- and oxidative conditions, according to ICH guidelines. The results were statistically compared to those obtained by comparison methods and were found to be in good agreement.

  1. Stability-indicating micelle-enhanced spectrofluorimetric method for determination of loratadine and desloratadine in dosage forms.

    PubMed

    Walash, M I; Belal, F; El-Enany, N; Eid, M; El-Shaheny, R N

    2011-01-01

    A highly sensitive and simple spectrofluorimetric method was developed for the determination of loratadine (LRT) and desloratadine (DSL) in their pharmaceutical formulations. The proposed method is based on investigation of the fluorescence spectral behaviour of LRT and DSL in a sodium dodecyl sulphate (SDS) micellar system. In aqueous solution of acetate buffer of pH 4.5, the fluorescence intensities of both LRT and DSL were greatly enhanced (240%) in the presence of SDS. The fluorescence intensity was measured at 438 nm after excitation at 290 nm for both drugs. The fluorescence-concentration plots were rectilinear over the range 0.05-2.0 µg/mL for both LRT and DSL, with lower detection limits of 5.13 × 10(-3) and 6.35 × 10(-3) µg/mL for LRT and DSL, respectively. The method was successfully applied to the analysis of the two drugs in their commercial tablets, capsules and syrups, and the results were in good agreement with those obtained with the official or comparison methods. The proposed method is specific for the determination of LRT in the presence of other co-formulated drugs, such as pseudoephedrine. The application of the proposed method was extended to stability studies of LRT and DSL after exposure to different forced degradation conditions, such as acidic, alkaline and oxidative conditions, according to ICH guidelines.

  2. Improvement of a stability-indicating method by Quality-by-Design versus Quality-by-Testing: a case of a learning process.

    PubMed

    Hubert, C; Lebrun, P; Houari, S; Ziemons, E; Rozet, E; Hubert, Ph

    2014-01-01

    The understanding of the method is a major concern when developing a stability-indicating method and even more so when dealing with impurity assays from complex matrices. In the presented case study, a Quality-by-Design approach was applied in order to optimize a routinely used method. An analytical issue occurring at the last stage of a long-term stability study involving unexpected impurities perturbing the monitoring of characterized impurities needed to be resolved. A compliant Quality-by-Design (QbD) methodology based on a Design of Experiments (DoE) approach was evaluated within the framework of a Liquid Chromatography (LC) method. This approach allows the investigation of Critical Process Parameters (CPPs), which have an impact on Critical Quality Attributes (CQAs) and, consequently, on LC selectivity. Using polynomial regression response modeling as well as Monte Carlo simulations for error propagation, Design Space (DS) was computed in order to determine robust working conditions for the developed stability-indicating method. This QbD compliant development was conducted in two phases allowing the use of the Design Space knowledge acquired during the first phase to define the experimental domain of the second phase, which constitutes a learning process. The selected working condition was then fully validated using accuracy profiles based on statistical tolerance intervals in order to evaluate the reliability of the results generated by this LC/ESI-MS stability-indicating method. A comparison was made between the traditional Quality-by-Testing (QbT) approach and the QbD strategy, highlighting the benefit of this QbD strategy in the case of an unexpected impurities issue. On this basis, the advantages of a systematic use of the QbD methodology were discussed.

  3. Development and stability of semisolid preparations based on a supercritical CO2 Arnica extract.

    PubMed

    Bilia, Anna Rita; Bergonzi, Maria Camilla; Mazzi, Giovanni; Vincieri, Franco Francesco

    2006-05-03

    Conventional herbal drug preparations (HDP) based on Arnica montana L. have a low content of the active principles, sesquiterpene lactones, which show poor stability and low physical compatibility in semisolid formulations. Recently, an innovative supercritical carbon dioxide (CO2) extract with high sesquiterpene content has been marketed. Development of six semisolid preparations (cetomacrogol, polysorbate 60, polawax, anphyphil, natrosol and sepigel) based on this innovative CO2 extract is discussed. Stability of these preparations was investigated according to ICH guidelines. The evaluation of in vitro release of active constituents was performed using the cell method reported in the European Pharmacopoeia. Preliminary data on in vivo permeation of three selected formulations is demonstrated using the "skin stripping" test, according to the FDA, in healthy subjects. Analysis of sesquiterpene lactones within the extract and in vitro and in vivo studies was performed by RP-HPLC-DAD-MS method. The cetomacrogol showed the best release profile in the in vitro test, while in the in vivo test the best preparation resulted polysorbate 60 and polawax.

  4. Comparison of Stability-Indicating LC Methods Using Light Scattering and Photodiode Array Detection with Monolithic Column for Determination of Quinapril and Hydrochlorothiazide.

    PubMed

    de Diego, Marta; Godoy, Ricardo; Mennickent, Sigrid; Vergara, Carola; Charnock, Henry; Hernández, Camilo

    2016-09-01

    Rapid stability-indicating LC methods for simultaneous analysis of quinapril and hydrochlorothiazide were developed, validated and compared using evaporative light scattering detection (ELSD) and diode array detection (DAD). For the separation of quinapril, hydrochlorothiazide and its major degradation products, a monolithic column was used and the analytes were eluted within 7 min, applying gradient mobile phase in both methods. Quinapril was subjected to hydrolytic, oxidative, thermal, humidity and photolytic stress conditions. Degradation products were well resolved from main peaks and from each other, proving the stability-indicating power of the methods. The response with DAD was linear and the response with ELSD was fitted to a power function, for quinapril and hydrochlorothiazide concentrations of 20-160 and 12.5-100 µg mL(-1), respectively. DAD method achieved better precision than ELSD method, the LOQ of DAD was lower and the accuracy of the methods was similar. Quinapril degrade by hydrolysis and thermal stress, showing the formation of quinaprilat and quinapril diketopiperazine as degradants, which were identified by MS-MS. The methods were successfully applied to quantify quinapril and hydrochlorothiazide in commercial tablets. LC-DAD and LC-ELSD methods are suitable to assess the stability and routine analysis of quinapril and hydrochlorothiazide in pharmaceutical industry.

  5. Advanced stability indicating chemometric methods for quantitation of amlodipine and atorvastatin in their quinary mixture with acidic degradation products

    NASA Astrophysics Data System (ADS)

    Darwish, Hany W.; Hassan, Said A.; Salem, Maissa Y.; El-Zeany, Badr A.

    2016-02-01

    Two advanced, accurate and precise chemometric methods are developed for the simultaneous determination of amlodipine besylate (AML) and atorvastatin calcium (ATV) in the presence of their acidic degradation products in tablet dosage forms. The first method was Partial Least Squares (PLS-1) and the second was Artificial Neural Networks (ANN). PLS was compared to ANN models with and without variable selection procedure (genetic algorithm (GA)). For proper analysis, a 5-factor 5-level experimental design was established resulting in 25 mixtures containing different ratios of the interfering species. Fifteen mixtures were used as calibration set and the other ten mixtures were used as validation set to validate the prediction ability of the suggested models. The proposed methods were successfully applied to the analysis of pharmaceutical tablets containing AML and ATV. The methods indicated the ability of the mentioned models to solve the highly overlapped spectra of the quinary mixture, yet using inexpensive and easy to handle instruments like the UV-VIS spectrophotometer.

  6. Development and Application of a High-Performance Liquid Chromatography Stability-Indicating Assay for Beyond-Use Date Determination of Compounded Topical Gels Containing Multiple Active Drugs.

    PubMed

    Gorman, Gregory; Sokom, Simara; Coward, Lori; Arnold, John J

    2017-01-01

    Topical gels compounded by pharmacists are important clinical tools for the management of pain. Nevertheless, there is often a dearth of information about the chemical stability of drugs included in these topical formulations, complicating the assignment of beyond-use dating. The purpose of this study was to develop a high-performance liquid chromatography photodiode array-based stability-indicating assay that could simultaneously resolve six drugs (amitriptyline, baclofen, clonidine, gabapentin, ketoprofen, lidocaine) commonly included in topical gels for pain management and their potential degradation products. Furthermore, this method was applied to the determination of beyond-use dating of combinations of these drugs prepared in commonly utilized bases (Lipobase, Lipoderm, Pluronic organogel). Gabapentin was determined to be the least stable component in all formulations tested. Measured stability ranged between 7 to 49 days depending on the base and other active drugs present in the formulation. In the absence of gabapentin, baclofen was the next least stable component, lasting for 120 days, regardless of the type of formulating base used.

  7. A Stability-Indicating HPLC-DAD Method for Determination of Stiripentol: Development, Validation, Kinetics, Structure Elucidation and Application to Commercial Dosage Form

    PubMed Central

    Darwish, Hany W.; Abdelhameed, Ali S.; Bakheit, Ahmed H.; Khalil, Nasr Y.; Al-Majed, Abdulrahman A.

    2014-01-01

    A rapid, simple, sensitive, and accurate isocratic reversed-phase stability-indicating high performance liquid chromatography method has been developed and validated for the determination of stiripentol and its degradation product in its bulk form and pharmaceutical dosage form. Chromatographic separation was achieved on a Symmetry C18 column and quantification was achieved using photodiode array detector (DAD). The method was validated in accordance with the ICH requirements showing specificity, linearity (r2 = 0.9996, range of 1–25 μg/mL), precision (relative standard deviation lower than 2%), accuracy (mean recovery 100.08 ± 1.73), limits of detection and quantitation (LOD = 0.024 and LOQ = 0.081 μg/mL), and robustness. Stiripentol was subjected to various stress conditions and it has shown marked stability under alkaline hydrolytic stress conditions, thermal, oxidative, and photolytic conditions. Stiripentol degraded only under acidic conditions, forming a single degradation product which was well resolved from the pure drug with significantly different retention time values. This degradation product was characterized by 1H-NMR and 13C-NMR spectroscopy as well as ion trap mass spectrometry. The results demonstrated that the method would have a great value when applied in quality control and stability studies for stiripentol. PMID:25371844

  8. Development and validation of a stability-indicating LC-UV method for the determination of pantethine and its degradation product based on a forced degradation study.

    PubMed

    Canavesi, Rossana; Aprile, Silvio; Varese, Elena; Grosa, Giorgio

    2014-08-01

    Pantethine (d-bis-(N-pantothenyl-β-aminoethyl)-disulfide, PAN), the stable disulfide form of pantetheine, has beneficial effects in vascular diseases being able to decrease the hyperlipidaemia, moderate the platelet function and prevent the lipid peroxidation. Furthermore, recent studies suggested that PAN may be an effective therapeutic agent for cerebral malaria and, possibly, for neurodegenerative processes. Interestingly, in the literature, there were no data dealing with the chemical stability and the analytical aspects of PAN. Hence, in the present work the chemical stability of PAN was for the first time established through a forced degradation study followed by liquid chromatography tandem mass spectrometry investigation showing the formation of three degradation products of PAN (PD1, PD2 and POx) arising from hydrolytic, thermal and oxidative stresses. Based on these data a stability-indicating LC-UV method for simultaneous estimation of PAN, and its most relevant degradation product (PD1) was developed and validated; moreover the method allowed also the separation and the quantification of the preservative system, constituted by a paraben mixture. The method showed linearity for PAN (0.4-1.2mgmL(-1)), MHB, PHB (0.4-1.2μgmL(-1)) and PD1 (2.5-100μgmL(-1)); the precision, determined in terms of intra-day and inter-day precision, expressed as RSDs, were in the ranges 0.4-1.2 and 0.7-1.4, respectively. The method demonstrated to be accurate and robust; indeed the average recoveries were 100.2, 99.9, and 100.0% for PAN, MHB and PHB, respectively, and 99.9% for PD1. By applying small variations of the mobile phase composition, counter-ion concentration and pH the separation of analytes was not affected. Finally, the applicability of this method was evaluated analyzing the available commercial forms at release as well as during stability studies.

  9. Longitudinal stability of social competence indicators in a Portuguese sample: Q-sort profiles of social competence, measures of social engagement, and peer sociometric acceptance.

    PubMed

    Santos, António J; Vaughn, Brian E; Peceguina, Inês; Daniel, João R

    2014-03-01

    This study examines the temporal stability (over 3 years) of individual differences in 3 domains relevant to preschool children's social competence: social engagement/motivation, profiles of behavior and personality attributes characteristic of socially competent young children, and peer acceptance. Each domain was measured with multiple indicators. Sociometric status categories (Asher & Dodge, 1986) and reciprocated friendships were derived from sociometric data. Composites for social competence domains were significantly associated across all time points. Within age-periods, social competence domains were associated with both sociometric and friendship status categories; however, neither sociometric status nor reciprocated friendships were stable over time. Nevertheless, analyses examining the social competence antecedents to reciprocated friendship at age-4 and age-5 suggested that more socially competent children in the prior year were more likely to have a reciprocated friendship in the current year. Popular and rejected sociometric status categories were also associated with social competence indicators in prior years, but this was most clearly seen at age-5.

  10. Stability-indicating UHPLC method for determination of nevirapine in its bulk form and tablets: identification of impurities and degradation kinetic study.

    PubMed

    Reis, Naialy Fernandes Araújo; de Assis, Jéssica Camille; Fialho, Sílvia Ligório; Pianetti, Gerson Antônio; Fernandes, Christian

    2016-07-15

    Nevirapine (NVP), a non-nucleoside reverse transcriptase inhibitor, is a drug widely used in the treatment of Acquired Immunodeficiency Syndrome (AIDS). The evaluation of NVP stability is of fundamental importance in order to guarantee drug product efficacy, safety and quality. In this study, NVP active pharmaceutical ingredient (API) and tablets were subjected to a detailed study of forced degradation, employing several degrading agents (acid, alkaline, water, metal ions, humidity, heat, light and oxidation agents). In order to determine NVP and the degradation products formed, a stability-indicating UHPLC method using fused core column was developed and validated. The separation was carried out using a Poroshell 120C18 column (100×2.1mm i.d.; 2.7μm particle size) and the mobile phase was composed of acetonitrile and water in a gradient elution, at a flow rate of 0.2ml/min. Chemical structures and mechanisms for the formation of three degradation products were proposed by means of LC/MS-MS. Also, NVP degradation kinetic was studied and its order of degradation evaluated. NVP was degraded in acidic and oxidative conditions and the degradation profile for NVP tablets and API were similar. The stability-indicating method proved to be selective for NVP and its degradation products. Calibration curve was linear in the range of 8-48μg/ml and the method showed to be precise, accurate and robust for both NVP API and tablets, with detection and quantification limits of 0.092μg/ml and 0.174μg/ml, respectively.

  11. Stability-indicating capillary zone electrophoresis method for the assessment of recombinant human interleukin-11 and its correlation with reversed-phase liquid chromatography and biossay.

    PubMed

    Souto, Ricardo Bizogne; Stamm, Fernanda Pavani; Schumacher, Jéssica Barbieri; Cardoso, Clovis Dervil Appratto; de Freitas, Guilherme Weber; Perobelli, Rafaela Ferreira; Dalmora, Sérgio Luiz

    2014-06-01

    A stability-indicating capillary zone electrophoresis (CZE) method was validated for the analysis of recombinant human interleukin-11(rhIL-11) using rupatadine fumarate, as internal standard (IS). A fused-silica capillary, (50 µm i.d.; effective length, 40 cm) was used at 25°C; the applied voltage was 20 kV. The background electrolyte solution consisted of 50 mmol L(-1) sodium dihydrogen phosphate solution at pH 3.0. Injections were performed using a pressure mode at 50 mbar for 45 s, with detection by photodiode array detector set at 196 nm. Specificity and stability-indicating capability were established in degradation studies, which also showed that there was no interference of the excipients. The method was linear over the concentration range of 1.0-300 µg mL(-1) (r(2)=0.9992) and the limit of detection (LOD) and limit of quantitation (LOQ) were 0.2 µg mL(-1) and 1.0 µg mL(-1), respectively. The accuracy was 100.4% with bias lower than 1.1%. Moreover, the in vitro cytotoxicity test of the degraded products showed significant differences (p<0.05). The method was applied for the content/potency assessment of rhIL-11 in biopharmaceutical formulations, and the results were correlated to those of a validated reversed-phase LC method (RP-LC) and an TF-1 cell culture assay, showing non-significant differences (p>0.05). In addition the CZE and RP-LC methods were applied for the analysis of rhIL-11 in human plasma. Therefore, the proposed alternative method can be applied to monitor stability, to assure the batch-to-batch consistency and quality of the bulk and finished biotechnology-derived medicine.

  12. A Rapid, Stability Indicating RP-UPLC Method for Simultaneous Determination of Ambroxol Hydrochloride, Cetirizine Hydrochloride and Antimicrobial Preservatives in Liquid Pharmaceutical Formulation

    PubMed Central

    Trivedi, Rakshit Kanubhai; Patel, Mukesh C.; Jadhav, Sushant B.

    2011-01-01

    A stability indicating reversed phase ultra performance liquid chromatography (RP-UPLC) method was developed for simultaneous determination of ambroxol hydrochloride (AMB), cetirizine hydrochloride (CTZ), methylparaben (MP) and propylparaben (PP) in liquid pharmaceutical formulation. The desired chromatographic separation was achieved on an Agilent Eclipse plus C18, 1.8 μm (50 × 2.1 mm) column using gradient elution at 237 nm detector wavelength. The optimized mobile phase consists of a mixture of 0.01 M phosphate buffer and 0.1 % triethylamine as a solvent-A and acetonitrile as a solvent-B. The developed method separates AMB, CTZ, MP and PP in presence of twelve known impurities/degradation products and one unknown degradation product within 3.5 min. Stability indicating capability was established by forced degradation experiments and seperation of known and unknown degradation products. The lower limit of quantification was established for AMB, CTZ, MP and PP. The developed RP-UPLC method was validated according to the International Conference on Harmonization (ICH) guidelines. This validated method is applied for simultaneous estimation of AMB, CTZ, MP and PP in commercially available syrup samples. Further, the method can be extended for estimation of AMB, CTZ, MP, PP and levo-cetirizine (LCTZ) in various commercially available dosage forms. PMID:21886901

  13. Development and Validation of a New Stability-Indicating RP-UPLC Method for the Quantitative Determination of Bromfenac Sodium and Its Impurities in an Ophthalmic Dosage Form.

    PubMed

    Koppala, Srinivasarao; Reddy, V Ranga; Anireddy, Jaya Shree

    2016-06-06

    A new rapid stability-indicating reversed-phase UPLC method was developed and validated for the determination of Bromfenac sodium and its impurities in Bromfenac ophthalmic solution. During literature search, only a few publications were found about Bromfenac sodium. There is no official monograph in the pharmacopoeias about Bromfenac sodium. Chromatographic separation has been achieved on a polar-embedded Waters Acquity BEH Shield RP18 (100 mm × 2.1 mm, 1.7 μm) column under gradient elution by using a binary mixture of potassium dihydrogen phosphate (0.01 M, pH 3.3) and acetonitrile (ACN) at a flow rate of 0.5 mL/min. Chromatogram was monitored at 265 nm using a photodiode array detector (PDA). The drug and its related impurities are eluted within 13 min. Resolution of Bromfenac sodium and all eight potential impurities have been achieved greater than 4.0 for all pairs of compounds. To prove the stability-indicating power of the method, the drug was subjected to hydrolytic (acid, alkaline and water), oxidative, photolytic and thermal stress, and the major degradation products were identified based on LC-MS analysis. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection, limit of quantification, precision, accuracy and robustness.

  14. Development and validation of a simple, sensitive, selective and stability-indicating RP-UPLC method for the quantitative determination of ritonavir and its related compounds.

    PubMed

    Koppala, Srinivasarao; Panigrahi, Bibhuranjan; Raju, S V N; Padmaja Reddy, K; Ranga Reddy, V; Anireddy, Jaya Shree

    2015-01-01

    A simple, sensitive, selective and reproducible stability-indicating ultra-performance liquid chromatographic method was developed for the quantitative determination of degradation products and process-related impurities of Ritonavir in a pharmaceutical dosage form. Chromatographic separation was achieved on a polar embedded Waters Acquity BEH Shield RP18 (100 × 2.1 mm, 1.7 μm) column thermostated at 50°C under gradient elution by using a binary mixture of potassium dihydrogen phosphate (0.01 M, pH 3.5) and acetonitrile at a flow rate of 0.5 mL/min. Chromatogram was monitored at 240 nm using a photodiode array detector. The drug and its related impurities are eluted within 20 min. To prove the stability-indicating power of the method, the drug was subjected to hydrolytic (acid, alkaline and water), oxidative, photolytic and thermal stress conditions. The unknown degradants were identified by the LC-MS-MS method, which revealed protonated molecular ion peaks [M + H](+) at m/z 551.40 for hydrolytic degradants, and m/z 737.60 and m/z 753.40 for photolytic degradants. A plausible mechanism for the formation of degradation and process impurities was proposed. The performance of the method was validated according to the International Conference on Harmonization guidelines.

  15. Development and Validation of a Stability-Indicating RP-UPLC Method for the Estimation of Impurities in Cinacalcet Hydrochloride API and its Formulation.

    PubMed

    Sunil Reddy, Pingili; Raju, Thummala Veera Raghava; Raju, Penmetsa Satyanarayana; Varma, Nadimpalli Sunil; Babu, Kondra Sudhakar

    2015-01-01

    A sensitive, stability-indicating, gradient reversed-phase ultra-performance liquid chromatography method has been developed for the quantitative estimation of cinacalcet hydrochloride impurities in active pharmaceutical ingredients and pharmaceutical formulations. Efficient chromatographic separation was achieved on an Acquity BEH Shield RP18, 100 × 2.1 mm, 1.7 µm column with the mobile phase containing pH 6.6 phosphate buffer and acetonitrile. The flow rate of the mobile phase was 0.3 mL min(-1) with a column temperature of 35°C and detection wavelength at 223 nm. The relative response factor values of (+)-R-1-(1-Naphthyl)ethylamine, regioisomer, diastereomer isomer-1, and diastereomer isomer-2 were 1.79, 0.99, 0.89, and 0.88, respectively. The cinacalcet hydrochloride formulation sample was subjected to the stress conditions of acid, base, oxidative, hydrolytic, thermal, humidity, and photolytic degradation. Cinacalcet hydrochloride was found to degrade significantly under the peroxide stress conditions. The degradation products were well-resolved from cinacalcet hydrochloride and its impurities. The peak purity test results confirmed that the cinacalcet hydrochloride peak was homogenous in all stress samples and the mass balance was found to be more than 96%, thus proving the stability-indicating power of the method. The developed method was validated according to ICH guidelines.

  16. Validated UPLC and TLC-Densitometry Stability Indicating Methods for the Determination of Rafoxanide in the Presence of Its Degradation Products.

    PubMed

    Saad, Ahmed S; Hamdy, Abdallah M; Salama, Fathy M; Abdelkawy, Mohamed

    2016-07-01

    Two sensitive and accurate stability-indicating chromatographic methods were developed and validated for the determination of rafoxanide (RFX). Degradation products were identified by mass spectrometry and IR spectroscopy. The first is ultra-performance liquid chromatography method where separation was performed using acetonitrile:0.005 M potassium dihydrogen orthophosphate (pH 3.5) in a ratio of 80:20 by volume as a mobile phase using a Hypersil GOLD™ C8 column 1.9 mm (50 × 2.1 mm), UV detection was adjusted at 220 nm and the flow rate was 0.6 mL min(-1) The other is a thin-layer chromatography-densitometry method where separation was achieved using a mobile phase composed of chloroform:ethyl acetate:toluene:ammonia (5:4:3:0.1 by volume) on silica gel 60 F254 plates, and densitometric detection was done at 280 nm. Validation was achieved as per the ICH guidelines. The proposed methods proved to be accurate, robust, specific and suitable for application as stability-indicating methods for routine analysis of RFX in quality control laboratories.

  17. Stability-indicating UPLC method for determination of Valsartan and their degradation products in active pharmaceutical ingredient and pharmaceutical dosage forms.

    PubMed

    Krishnaiah, Ch; Reddy, A Raghupathi; Kumar, Ramesh; Mukkanti, K

    2010-11-02

    A simple, precise, accurate stability-indicating gradient reverse phase ultra-performance liquid chromatographic (RP-UPLC) method was developed for the quantitative determination of purity of Valsartan drug substance and drug products in bulk samples and pharmaceutical dosage forms in the presence of its impurities and degradation products. The method was developed using Waters Aquity BEH C18 (100 mm x 2.1 mm, 1.7 microm) column with mobile phase containing a gradient mixture of solvents A and B. The eluted compounds were monitored at 225 nm, the run time was within 9.5 min, which Valsartan and its seven impurities were well separated. Valsartan was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. Valsartan was found to degrade significantly in acid and oxidative stress conditions and stable in base, hydrolytic and photolytic degradation conditions. The degradation products were well resolved from main peak and its impurities, proving the stability-indicating power of the method. The developed method was validated as per international conference on harmonization (ICH) guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness. This method was also suitable for the assay determination of Valsartan in pharmaceutical dosage forms.

  18. Development and validation of a stability-indicating assay including the isolation and characterization of degradation products of metaxalone by LC-MS.

    PubMed

    Rao, R Nageswara; Farah, Hassan; Sahu, Prafulla Kumar; Janarthan, Muthumani; Naidu, Ch Gangu

    2013-12-01

    A stability-indicating reverse-phase high-performance liquid chromatography-mass spectrometric method was developed and validated for the assay of metaxalone through forced degradation under acidic, alkaline, photo, oxidative and peroxide stress conditions. Separation of degradation products was accomplished on a reverse-phase Phenomenex C18 (250 × 4.6 mm, 5 µm) column thermostated at 25 °C using 10 mM aqueous ammonium acetate: methanol (35:65 v/v) as mobile phase in an isocratic mode of elution. The eluents were detected at 275 nm by photo diode array detector and mass detectors connected in series. Two unknown base hydrolysis products of metaxalone were identified and characterized as (a) methyl 3-(3,5-dimethylphenoxy)-2-hydroxypropylcarbamate and (b) 1-(3,5-dimethylphenoxy)-3-aminopropan-2-ol by MS, (1)H NMR and FTIR spectroscopy. The method was validated as per International Conference on Harmonization guidelines and metaxalone was selectively determined in presence of its degradation impurities, demonstrating its stability-indicating nature.

  19. Development and Validation of a Stability-Indicating RP-UPLC Method for the Estimation of Impurities in Cinacalcet Hydrochloride API and its Formulation

    PubMed Central

    Sunil Reddy, Pingili; Raju, Thummala Veera Raghava; Raju, Penmetsa Satyanarayana; Varma, Nadimpalli Sunil; Babu, Kondra Sudhakar

    2015-01-01

    A sensitive, stability-indicating, gradient reversed-phase ultra-performance liquid chromatography method has been developed for the quantitative estimation of cinacalcet hydrochloride impurities in active pharmaceutical ingredients and pharmaceutical formulations. Efficient chromatographic separation was achieved on an Acquity BEH Shield RP18, 100 × 2.1 mm, 1.7 µm column with the mobile phase containing pH 6.6 phosphate buffer and acetonitrile. The flow rate of the mobile phase was 0.3 mL min−1 with a column temperature of 35°C and detection wavelength at 223 nm. The relative response factor values of (+)-R-1-(1-Naphthyl)ethylamine, regioisomer, diastereomer isomer-1, and diastereomer isomer-2 were 1.79, 0.99, 0.89, and 0.88, respectively. The cinacalcet hydrochloride formulation sample was subjected to the stress conditions of acid, base, oxidative, hydrolytic, thermal, humidity, and photolytic degradation. Cinacalcet hydrochloride was found to degrade significantly under the peroxide stress conditions. The degradation products were well-resolved from cinacalcet hydrochloride and its impurities. The peak purity test results confirmed that the cinacalcet hydrochloride peak was homogenous in all stress samples and the mass balance was found to be more than 96%, thus proving the stability-indicating power of the method. The developed method was validated according to ICH guidelines. PMID:26839840

  20. A validated stability-indicating normal phase LC method for clopidogrel bisulfate and its impurities in bulk drug and pharmaceutical dosage form.

    PubMed

    Durga Rao, Dantu; Kalyanaraman, L; Sait, Shakil S; Venkata Rao, P

    2010-05-01

    A novel stability-indicating normal phase liquid chromatographic (NP-LC) method was developed for the determination of purity of clopidogrel drug substance and drug products in bulk samples and pharmaceutical dosage forms in the presence of its impurities and degradation products. This method is capable of separating all the related substances of clopidogrel along with the chiral impurities. This method can be also be used for the estimation of assay of clopidogrel in drug substance as well as in drug product. The method was developed using Chiralcel OJ-H (250mmx4.6mm, 5microm) column. n-Hexane, ethanol and diethyl amine in 95:5:0.05 (v/v/v) ratio was used as a mobile phase. The eluted compounds were monitored at 240nm. Clopidogrel bisulfate was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. The degradation products were well resolved from main peak and its impurities, proving the stability-indicating power of the method. The developed method was validated as per International Conference on Harmonization (ICH) guidelines with respect to specificity, limit of detection, limit of quantification, precision, linearity, accuracy, robustness and system suitability.

  1. Development and validation of a stability-indicating capillary zone electrophoretic method for the assessment of entecavir and its correlation with liquid chromatographic methods.

    PubMed

    Dalmora, Sergio Luiz; Nogueira, Daniele Rubert; D'Avila, Felipe Bianchini; Souto, Ricardo Bizogne; Leal, Diogo Paim

    2011-01-01

    A stability-indicating capillary zone electrophoresis (CZE) method was validated for the analysis of entecavir in pharmaceutical formulations, using nimesulide as an internal standard. A fused-silica capillary (50 µm i.d.; effective length, 40 cm) was used while being maintained at 25°C; the applied voltage was 25 kV. A background electrolyte solution consisted of a 20 mM sodium tetraborate solution at pH 10. Injections were performed using a pressure mode at 50 mbar for 5 s, with detection at 216 nm. The specificity and stability-indicating capability were proven through forced degradation studies, evaluating also the in vitro cytotoxicity test of the degraded products. The method was linear over the concentration range of 1-200 µg mL(-1) (r(2) = 0.9999), and was applied for the analysis of entecavir in tablet dosage forms. The results were correlated to those of validated conventional and fast LC methods, showing non-significant differences (p > 0.05).

  2. A validated stability-indicating LC method for acetazolamide in the presence of degradation products and its process-related impurities.

    PubMed

    Srinivasu, Prabha; Subbarao, Devarakonda V; Vegesna, Raju V K; Sudhakar Babu, K

    2010-05-01

    The objective of the current study was to develop a validated, specific and stability-indicating reverse phase liquid chromatographic method for the quantitative determination of acetazolamide and its related substances. The determination was done for an active pharmaceutical ingredient, its pharmaceutical dosage form in the presence of degradation products, and its process-related impurities. The drug was subjected to stress conditions of hydrolysis (acid and base), oxidation, photolysis and thermal degradation as per International Conference on Harmonization (ICH) prescribed stress conditions to show the stability-indicating power of the method. Significant degradation was observed during acid and base hydrolysis, and the major degradant was identified by LC-MS, FTIR and (1)H/(13)C NMR spectral analysis. The chromatographic conditions were optimized using an impurity-spiked solution and the generated samples were used for forced degradation studies. In the developed HPLC method, the resolution between acetazolamide and, its process-related impurities (namely imp-1, imp-2, imp-3, imp-4 and its degradation products) was found to be greater than 2. The chromatographic separation was achieved on a C18, 250mmx4.6mm, 5microm column. The LC method employed a linear gradient elution, and the detection wavelength was set at 254nm. The stress samples were assayed against a qualified reference standard and the mass balance was found to be close to 99.6%. The developed RP-LC method was validated with respect to linearity, accuracy, precision and robustness.

  3. Stress Degradation Behavior of Abacavir Sulfate and Development of a Suitable Stability-Indicating UHPLC Method for the Determination of Abacavir, its Related Substances, and Degradation Products.

    PubMed

    Vukkum, Pallavi; Deshpande, Girish R; Babu, J Moses; Muralikrishna, R; Jagu, Pavani

    2012-01-01

    A novel, stability-indicating UHPLC method was developed for the quantitative determination of Abacavir sulfate, its related substances, and forced degradation impurities in bulk drugs. The chromatographic separation was achieved on a Waters Acquity BEH C(8), 50 mm × 2.1 mm, 1.7 μm particle size column with a mobile containing a gradient mixture of solution A (0.10 % v/v o-phosphoric acid in water) and solution B (0.10% v/v o-phosphoric acid in methanol). The flow rate was set at 0.40 mL/min and the run time was 6.0 min. The drug substance was subjected to the stress studies of hydrolysis, oxidation, photolysis, and thermal degradation. Abacavir sulfate was found to degrade significantly under acidic hydrolysis and oxidative stress conditions. The formed degradation products were reported and were well-resolved from Abacavir and its related substances. The mass balance was found to be satisfactory in all of the stress conditions, thus proving the stability-indicating capability of the method. The developed UHPLC method was validated to be in agreement with ICH requirements and found to be rapid, accurate, precise, linear, specific, and suitable for the quantitative determination of related substances and degradants in the bulk drug samples of Abacavir sulfate.

  4. Determination of lumiracoxib by a validated stability-indicating MEKC method and identification of its degradation products by LC-ESI-MS studies.

    PubMed

    Sangoi, Maximiliano S; Wrasse-Sangoi, Micheli; Oliveira, Paulo R; Bernardi, Larissa S

    2011-08-01

    A stability-indicating MEKC method was developed and validated for the analysis of lumiracoxib (LMC) in pharmaceutical formulations using nimesulide as the internal standard (IS). Optimal conditions for the separation of LMC and degradation products were investigated. The method employed 50 mM borate buffer and 50 mM anionic detergent SDS solution at pH 9.0. MEKC method was performed on a fused-silica capillary (50 μm id; effective length, 40 cm) maintained at 30°C. The applied voltage was 20 kV and photodiode array (PDA) detector was set at 208 nm. The method was validated in accordance with the International Conference on Harmonisation requirements. The stability-indicating capability of the method was established by enforced degradation studies combined with peak purity assessment using PDA detection. The degradation products formed under stressed conditions were investigated by LC-ESI-MS and the two degraded products were identified. MEKC method was linear over the concentration range of 5-150 μg/mL (r(2) =0.9999) of LMC. The method was precise, accurate, with LOD and LOQ of 1.34 and 4.48 μg/mL, respectively. The robustness was proved by a fractional factorial design evaluation. The proposed MEKC method was successfully applied for the quantitative analysis of LMC in tablets to support the quality control.

  5. Development and Validation of a Stability-Indicating RP-UPLC Method for Determination of Rosuvastatin and Related Substances in Pharmaceutical Dosage Form.

    PubMed

    Trivedi, Harshal Kanubhai; Patel, Mukesh C

    2012-01-01

    A stability-indicating reversed phase ultra performance liquid chromatographic (RP-UPLC) method was developed for the determination of related substances in rosuvastatin calcium (ROSV) tablet dosage form. The chromatographic separation was achieved on an Acquity BEH C18 (100 mm × 2.1 mm, 1.7 μm) column with mobile phase containing a gradient mixture of solvent-A (0.1% trifluoroacetic acid) and solvent-B (methanol). The eluted compounds were monitored at 240 nm and the run time was 10.0 min. Degradation behavior of the ROSV was studied under various degradation stress conditions. Four major unknown degradation products (late eluting impurities) were found in acid stress condition and two unknown degradation products were found in oxidative stress condition. The developed method separates (six) unknown impurities, (three) known impurities and ROSV substance from each other, providing the stability-indicating power of the method. The developed RP-UPLC method was validated according to the International Conference on Harmonization (ICH) guidelines. The developed and validated RP-UPLC method is LC-MS compatible and can be applied for identification of eluted unknown impurities of ROSV.

  6. Is there any association between imidapril hydrochloride stability profile under dry air conditions and cancer initiation?

    PubMed

    Regulska, Katarzyna; Murias, Marek; Stanisz, Beata; Regulski, Miłosz

    2013-11-18

    Stability study for imidapril hydrochloride (IMD) was performed under stress conditions of increased temperature (T=373 K) and decreased relative air humidity (RH=0%) in order to obtain and identify its degradation product. The degradation sample stored for 15 days under the above environmental conditions was analyzed by LC-MS technique and it was found that the only degradation impurity formed in the course of the investigated drug degradation was IMD diketopiperazine derivative (DKP) which was produced by dehydration and intramolecular cyclization. The kinetics of its formation was analyzed by a revalidated RP-HPLC method and the kinetic model of this reaction was established. It was concluded that the DKP formation follows Prout-Tompkins kinetics with the rate constant k±Δk=2.034±0.157×10(-6) [s(-1)]. The obtained degradation impurity was further assessed with respect to its mutagenic potential using commercial Ames MPF 98/100 microplate format mutagenicity assay kit equipped with Salmonella typhimurium strains TA 98 and TA 100. Both strains were exposed to six concentrations (in a range of 0.16-5.0mg/mL) of DKP in the presence and absence of metabolic activation system. No mutagenic effect was observed confirming that the presence of DKP in IMD final dosage form has no impact on cancer initiation.

  7. Anthraquinone derivatives based natural dye from Rheum emodi as a probe for thermal stability of proteins: spectroscopic and chromatographic studies.

    PubMed

    Sharma, Nandini; Kumar, Rajesh; Sinha, Arun K; Reddy, Peram B; Nayeem, Shahid M; Deep, Shashank

    2012-03-25

    Rheum emodi is a storehouse of a large number of anthraquinone derivatives which are known for a large number of biological activities of significant potency. In this work, a study on the interactions between anthraquinone derivatives based natural dye isolated from R. emodi and different proteins has been reported for the first time, revealing the use of dye as an extrinsic probe to determine the stability of these proteins alone and in the presence of additives. The stability parameters have been evaluated as a change in the fluorescence intensity of the dye as a function of temperature due to the differential interaction of the dye with various conformations of a protein. Also, the effect of the change in polarity of the solvent on the fluorescence emission spectra of dye was studied where high quantum yield was observed in alcohol as compared to water. The RP-HPLC characterization of the dye revealed the presence of anthraquinones glycosides as main compounds in it. Thus, natural dyes may be used as biosensors to follow the conformational changes in proteins.

  8. ESI-MSn and LC-ESI-MS studies to characterize forced degradation products of bosentan and a validated stability-indicating LC-UV method.

    PubMed

    Bansal, Gulshan; Singh, Ranjit; Saini, Balraj; Bansal, Yogita

    2013-01-01

    The present study reports the characterization of forced degradation products of bosentan and a validated stability-indicating HPLC method for the stability testing of bosentan tablets. The forced degradation was carried out under the conditions of hydrolysis, oxidation, dry heat and photolysis. The drug was found unstable in acid, alkali and oxidative media whereas stable to the hydrolysis in water, to dry heat and to photolysis. In total, six degradation products were formed in all conditions which were resolved in a single run on a C-18 column with gradient elution using ammonium acetate buffer (pH 4.5, 5.0mM), methanol and acetonitrile. Structures of all the degradation products were characterized through +ESI-MS(n) and LC-ESI-MS spectral data of bosentan as well as LC-ESI-MS spectral data of the products. The products II-VI were characterized as 6-amino-[2,2']bipyrimidinyl-4,5-diol, 6-amino-5-(2-methoxyphenoxy)-[2,2']-bipyrimidinyl-4-ol, 2-[6-amino-5-(2-methoxyphenoxy)-[2,2']-bipyrimidinyl-4-yloxy]-ethanol, 4-tert-butyl-N-[6-(1-methoxyethoxy)-5-(2-methoxyphenoxy)-[2,2']-bipyrimidinyl-4-yl]-benzenesulfonamide and 4-tert-butyl-N-[6-hydroxy-5-(2-methoxyphenoxy)-[2,2']bipyrimidinyl-4-yl]-benzenesulfonamide, respectively. The peak of the product I was found to be due to two secondary degradation products which co-eluted and were characterized as β-hydroxyethyl p-tert-butylphenylsulfonate (Ia) and 2-[2-(2-hydroxyethoxy)-phenoxy]-ethanol (Ib). These products were formed due to hydrolysis of sulfonamide and alkylaryl ether and the diaryl ether linkages as well as dehydration of the primary alcohol group. The most probable degradation mechanisms were proposed. The HPLC method was found to be stability-indicating, linear (2-100 μg ml(-1)), accurate, precise, sensitive, specific, rugged and robust for quantitation of the drug. The method was applied to the stability testing of the commercially available bosentan tablets successfully.

  9. Rapid separation of seed gliadins by reversed-phase ultra performance liquid chromatography (RP-UPLC) and its application in wheat cultivar and germplasm identification.

    PubMed

    Han, Caixia; Lu, Xaiobing; Yu, Zitong; Li, Xiaohui; Ma, Wujun; Yan, Yueming

    2015-01-01

    To separate gliadin from wheat flour, a novel and stability-indicating reversed-phase ultra performance liquid chromatography (RP-UPLC) method is established and optimized. A comparative analysis of routine capillary electrophoresis (CE), reversed-phase high-performance liquid chromatography (RP-HPLC), and RP-UPLC was performed and the results showed that the resolution and efficiency of RP-UPLC were significantly higher than those of CE and RP-HPLC. Characteristic RP-UPLC patterns of different bread wheat variety and related species were readily identified. These results demonstrated that our RP-UPLC procedure resulted in significant improvements in sensitivity, speed, and resolution, and thus is highly useful in wheat cultivar and germplasm identification.

  10. Development of a stability-indicating high-performance liquid chromatographic method for the simultaneous determination of alprazolam and sertraline in combined dosage forms.

    PubMed

    Pathak, Ashutosh; Rajput, Sadhana J

    2008-01-01

    The objective of the current study was to develop a validated stability-indicating high-performance liquid chromatographic method for alprazolam and sertraline in combined dosage forms. The method was validated by subjecting the drugs to forced decomposition under hydrolysis, oxidation, photolysis, and thermal stress conditions prescribed by the International Conference on Harmonization. The drugs were successfully separated from major and minor degradation products on a reversed-phase C18 column by using 75 mM potassium dihydrogen phosphate buffer (pH 4.3)-acetonitrile-methanol (50 + 45 + 5, v/v/v) as the mobile phase with determination at 227 nm. The flow rate was 0.9 mL/min. The method was validated with respect to linearity, precision, accuracy, system suitability, and robustness. The responses were linear over the ranges of 1-80 and 5-200 microg/mL for alprazolam and sertraline, respectively. The recoveries of both drugs from a mixture of degradation products were in the range of 97-101%. The utility of the procedure was verified by its application to marketed formulations that were subjected to accelerated stability studies. The method distinctly separated the drugs and degradation products, even in actual samples. The products formed in marketed tablets were similar to those formed during stress studies.

  11. A stability-indicating, ion-pairing, reversed-phase liquid chromatography method for studies of daunorubicin degradation in i.v. infusion fluids.

    PubMed

    Respaud, R; Quenum, L; Plichon, C; Tournamille, J F; Gyan, E; Antier, D; Viaud-Massuard, M C

    2013-09-01

    A new stability-indicating method based on high-performance liquid chromatography coupled to ultraviolet and evaporative light scattering detection (HPLC-UV-ELSD) was developed for the quantification of daunorubicin. This is an ion-pairing, reversed-phase method. The column was a Synergi MAX-RP C12 4 μm (150 mm × 4.6 mm). The mobile phase was 6.2mM nonafluoropentanoic acid in aqueous solution and acetonitrile under isocratic elution mode. The drug was subjected to oxidation, basic and acid hydrolysis to apply stress conditions. Good resolution was achieved between daunorubicin, related products and all degradation products in an overall analytical run time of approximately 16 min with the parent compound daunorubicin eluting at approximately 8 min. The method was fully validated according to ICH guidelines and SFSTP protocols in terms of accuracy, precision, specificity and linearity. For daunorubicin, the decision criteria selected consisted of the acceptability limits (±3%) and the proportion of results within the calculated tolerance intervals (95%). In conclusion, the proposed analytical procedures were validated over the selected validation domains daunorubicin (0.25-0.45 mg/mL) and shown to provide a very effective method. Physical and chemical stability study was carried out on daunorubicin preparation in our hospital centralized pharmacy unit.

  12. A Stability-Indicating HPLC-DAD Method for Determination of Ferulic Acid into Microparticles: Development, Validation, Forced Degradation, and Encapsulation Efficiency

    PubMed Central

    Toledo, Maria da Graça; Pupo, Yasmine Mendes; Padilha de Paula, Josiane; Zanin, Sandra Maria Warumby

    2015-01-01

    A simple stability-indicating HPLC-DAD method was validated for the determination of ferulic acid (FA) in polymeric microparticles. Chromatographic conditions consisted of a RP C18 column (250 mm × 4.60 mm, 5 μm, 110 Å) using a mixture of methanol and water pH 3.0 (48 : 52 v/v) as mobile phase at a flow rate of 1.0 mL/min with UV detection at 320 nm. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of quantification, limit of detection, accuracy, precision, and robustness provided suitable results regarding all parameters investigated. The calibration curve was linear in the concentration range of 10.0–70.0 μg/mL with a correlation coefficient >0.999. Precision (intraday and interday) was demonstrated by a relative standard deviation lower than 2.0%. Accuracy was assessed by the recovery test of FA from polymeric microparticles (99.02% to 100.73%). Specificity showed no interference from the components of polymeric microparticles or from the degradation products derived from acidic, basic, and photolytic conditions. In conclusion, the method is suitable to be applied to assay FA as bulk drug and into polymeric microparticles and can be used for studying its stability and degradation kinetics. PMID:26075139

  13. Rapid and simple stability indicating HPLC method for the determination of cilazapril in pure substance and pharmaceutical formulation in comparison with classic and derivative spectrophotometric methods.

    PubMed

    Paszun, Sylwia K; Stanisz, Beata; Pawłowski, Wojciech

    2012-01-01

    The present study describes development and subsequent validation of high performance liquid chromatographic method (HPLC) in comparison with spectrophotometric methods (classic, first, second and third order derivative) for determination of pure cilazapril in substance and pharmaceutical preparation. The main aim of this study was to find the method suitable not only for determination of cilazapril, but additionally useful in degradation kinetic study. Only the HPLC method is stability indicating. The HPLC method utilizes LiChroCART 250-4 HPLC-Cartridge, LiChrospher 100 RP-18 (5 μm) column, at ambient temperature, eluted at the flow rate 1.0 mL/min. The mobile phase consists of acetonitrile, methanol and phosphate buffer (pH 2.0) (60:10:30, v/v/v). Wavelength of detection is set at 212 nm. Benzocaine is used as an internal standard. The second and third order derivative spectrophotometric methods can be applied for the cilazapril analysis in substance and tablet, but not for stability evaluation (the lack of selectivity towards degradation product).

  14. A Stability-Indicating HPLC-DAD Method for Determination of Ferulic Acid into Microparticles: Development, Validation, Forced Degradation, and Encapsulation Efficiency.

    PubMed

    Nadal, Jessica Mendes; Toledo, Maria da Graça; Pupo, Yasmine Mendes; Padilha de Paula, Josiane; Farago, Paulo Vitor; Zanin, Sandra Maria Warumby

    2015-01-01

    A simple stability-indicating HPLC-DAD method was validated for the determination of ferulic acid (FA) in polymeric microparticles. Chromatographic conditions consisted of a RP C18 column (250 mm × 4.60 mm, 5 μm, 110 Å) using a mixture of methanol and water pH 3.0 (48 : 52 v/v) as mobile phase at a flow rate of 1.0 mL/min with UV detection at 320 nm. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of quantification, limit of detection, accuracy, precision, and robustness provided suitable results regarding all parameters investigated. The calibration curve was linear in the concentration range of 10.0-70.0 μg/mL with a correlation coefficient >0.999. Precision (intraday and interday) was demonstrated by a relative standard deviation lower than 2.0%. Accuracy was assessed by the recovery test of FA from polymeric microparticles (99.02% to 100.73%). Specificity showed no interference from the components of polymeric microparticles or from the degradation products derived from acidic, basic, and photolytic conditions. In conclusion, the method is suitable to be applied to assay FA as bulk drug and into polymeric microparticles and can be used for studying its stability and degradation kinetics.

  15. Development and validation of stability-indicating TLC-densitometric method for determination of betaxolol with LC-ESI/MS analysis of degradation product.

    PubMed

    Kwiecień, Anna; Krzek, Jan; Walczak, Maria; Mazur, Mateusz

    2013-01-01

    The purpose of this work was to develop a sensitive stability indicating TLC-densitometric method for the determination of betaxolol (Bx) in pharmaceutical preparations and to study the stability of Bx in acidic solutions. The method was developed on TLC aluminium plates precoated with silica gel F254using the mobile phase chloroform-methanol-ammonia 25% (18 : 4: 0.2, v/v/v) which gives compact spots for Bx (R(f) approximately equal to 0.64) and its degradation product (R(f) approximately equal to 0.39). Densitometric analysis was carried out in UV at 280 nm. The developed method is highly sensitive (LOD = 66.6 ng/spot, LOQ = 200 ng/spot), precise (RSD = 2.73%) and accurate (mean recovery = 100.28% at 100% level). Bx was subjected to acidic and alkaline hydrolysis but degradation was observed only in acidic solutions. The degradation process was described with kinetic and thermodynamic parameters. Based on LC-ESI/MS analysis, it was found that Bx decomposes in acidic solution to produce ethoxyphenoxy-3-[(1-methylethyl)amino]propan-2-ol.

  16. Stability-indicating RP-LC method for the determination of vildagliptin and mass spectrometry detection for a main degradation product.

    PubMed

    Barden, Amanda Thomas; Salamon, Bárbara; Schapoval, Elfrides Eva Sherman; Steppe, Martin

    2012-05-01

    A simple, precise and stability-indicating reversed-phase liquid chromatography method was developed and validated for the determination of vildagliptin (VLG) in pharmaceutical dosage form. The chromatographic separation was obtained within 6 min and was linear in the range of 20-80 µg/mL (r(2) = 0.9999). Limit of detection and limit of quantitation were 0.63 and 2.82 µg/mL, respectively. The method was validated in accordance with International Conference on Harmonization acceptance criteria for specificity, linearity, precision, accuracy, robustness and system suitability. Stress studies were carried out and no interference of the degradation products was observed. The excipients did not interfere in the determination of VLG. Furthermore, the main degradation product obtained from the stress studies (thermal, oxidative and alkaline hydrolysis) was evaluated for mass spectrometry and its molecular structure was predicted. The proposed method was successfully applied for the quantitative analysis of VLG in tablet dosage form, which will help to improve quality control and contribute to stability studies of pharmaceutical tablets containing this drug.

  17. A comparative study between three stability indicating spectrophotometric methods for the determination of diatrizoate sodium in presence of its cytotoxic degradation product based on two-wavelength selection

    NASA Astrophysics Data System (ADS)

    Riad, Safaa M.; El-Rahman, Mohamed K. Abd; Fawaz, Esraa M.; Shehata, Mostafa A.

    2015-06-01

    Three sensitive, selective, and precise stability indicating spectrophotometric methods for the determination of the X-ray contrast agent, diatrizoate sodium (DTA) in the presence of its acidic degradation product (highly cytotoxic 3,5-diamino metabolite) and in pharmaceutical formulation, were developed and validated. The first method is ratio difference, the second one is the bivariate method, and the third one is the dual wavelength method. The calibration curves for the three proposed methods are linear over a concentration range of 2-24 μg/mL. The selectivity of the proposed methods was tested using laboratory prepared mixtures. The proposed methods have been successfully applied to the analysis of DTA in pharmaceutical dosage forms without interference from other dosage form additives. The results were statistically compared with the official US pharmacopeial method. No significant difference for either accuracy or precision was observed.

  18. Determination of duloxetine hydrochloride in the presence of process and degradation impurities by a validated stability-indicating RP-LC method.

    PubMed

    Raman, N V V S S; Harikrishna, K A; Prasad, A V S S; Reddy, K Ratnakar; Ramakrishna, K

    2010-03-11

    A stability-indicating gradient reverse phase liquid chromatographic purity and assay method for duloxetine hydrochloride (DUH) was developed and validated. DUH was subjected to the stress conditions and it is sensitive towards oxidative, acid and hydrolytic degradation. Successful separation of DUH from its two process impurities and one degradation impurity formed under stress conditions was achieved on a Symmetry C18, 250x4.6mm, 5microm column using a gradient mixture of solvent A (0.01M potassium dihydrogen orthophosphate having 0.2% triethyl amine, pH adjusted to 2.5 with orthophosphoric acid) and solvent B (20:80 v/v mixture of acetonitrile and methanol). The flow rate is 1ml/min and the detection wavelength is 230nm. The mass balance was found to be in the range of 99.2-99.7% in all the stressed conditions.

  19. Stability-indicating reversed-phase HPLC method development and characterization of impurities in vortioxetine utilizing LC-MS, IR and NMR.

    PubMed

    Liu, Lei; Cao, Na; Ma, Xingling; Xiong, Kaihe; Sun, Lili; Zou, Qiaogen; Yao, Lili

    2016-01-05

    The current study reports the development and validation of a stability-indicating reversed phase HPLC method for the separation and identification of potential impurities in vortioxetine, a recently developed antidepressant. The structures of a new compound and four process-related impurities formed during the synthesis were characterized and confirmed by NMR, MS, and IR spectroscopy analyses. The most probable formation mechanisms of the impurities identified were proposed. Based on the characterization data, the new compound was proposed to be 1-[4-[(2,4-dimethylphenyl)thio]phenyl]-piperazine. In addition, an efficient chromatographic method was optimized to separate and quantify the impurities, which were obtained in the 0.05-0.75 μg/mL range. The developed HPLC method was validated with respect to accuracy, precision, linearity, robustness, and limits of detection and quantitation.

  20. Support vector regression and artificial neural network models for stability indicating analysis of mebeverine hydrochloride and sulpiride mixtures in pharmaceutical preparation: A comparative study

    NASA Astrophysics Data System (ADS)

    Naguib, Ibrahim A.; Darwish, Hany W.

    2012-02-01

    A comparison between support vector regression (SVR) and Artificial Neural Networks (ANNs) multivariate regression methods is established showing the underlying algorithm for each and making a comparison between them to indicate the inherent advantages and limitations. In this paper we compare SVR to ANN with and without variable selection procedure (genetic algorithm (GA)). To project the comparison in a sensible way, the methods are used for the stability indicating quantitative analysis of mixtures of mebeverine hydrochloride and sulpiride in binary mixtures as a case study in presence of their reported impurities and degradation products (summing up to 6 components) in raw materials and pharmaceutical dosage form via handling the UV spectral data. For proper analysis, a 6 factor 5 level experimental design was established resulting in a training set of 25 mixtures containing different ratios of the interfering species. An independent test set consisting of 5 mixtures was used to validate the prediction ability of the suggested models. The proposed methods (linear SVR (without GA) and linear GA-ANN) were successfully applied to the analysis of pharmaceutical tablets containing mebeverine hydrochloride and sulpiride mixtures. The results manifest the problem of nonlinearity and how models like the SVR and ANN can handle it. The methods indicate the ability of the mentioned multivariate calibration models to deconvolute the highly overlapped UV spectra of the 6 components' mixtures, yet using cheap and easy to handle instruments like the UV spectrophotometer.

  1. A Validated Stability-Indicating RP-UPLC Method for Simultaneous Determination of Desloratadine and Sodium Benzoate in Oral Liquid Pharmaceutical Formulations

    PubMed Central

    Kumar, Navneet; Sangeetha, Dhanaraj; Reddy, Pingili Sunil; Prakash, Lakkireddy

    2012-01-01

    A novel, sensitive and selective stability-indicating gradient reverse phase ultra performance liquid chromatographic method was developed and validated for the quantitative determination of desloratadine and sodium benzoate in pharmaceutical oral liquid formulation. The chromatographic separation was achieved on Acquity BEH C8 (100 mm × 2.1 mm) 1.7 μm column by using mobile phase containing a gradient mixture of solvent A (0.05 M KH2PO4 and 0.07 M triethylamine, pH 3.0) and B (50:25:25 v/v/v mixture of acetonitrile, methanol and water) at flow rate of 0.4 mL/min. Column temperature was maintained at 40°C and detection was carried out at a wavelength of 272 nm. The described method shows excellent linearity over a range of 0.254 μg/mL to 76.194 μg/mL for desloratadine and 1.006 μg/mL to 301.67 μg/mL for sodium benzoate. The correlation coefficient for desloratadine and sodium benzoate was more than 0.999. To establish stability-indicating capability of the method, drug product was subjected to the stress conditions of acid, base, oxidative, hydrolytic, thermal and photolytic degradation. The degradation products were well resolved from desloratadine and sodium benzoate. The developed method was validated as per international ICH guidelines with respect to specificity, linearity, LOD, LOQ, accuracy, precision and robustness. PMID:22396911

  2. Development and validation of a stability-indicating reverse phase ultra performance liquid chromatographic method for the estimation of nebivolol impurities in active pharmaceutical ingredients and pharmaceutical formulation.

    PubMed

    Thummala, Veera Raghava Raju; Lanka, Mohana Krishna

    2015-10-01

    A sensitive, stability-indicating gradient reverse phase ultra performance liquid chromatographic method has been developed for the quantitative estimation of nebivolol impurities in active pharmaceutical ingredient (API) and pharmaceutical formulation. Efficient chromatographic separation was achieved on an Acquity BEH C18 column (100 mm x 2.1 mm, 1.7 μm) with mobile phase of a gradient mixture. The flow rate of the mobile phase was 0.18 mL/min with column temperature of 30 degrees C and detection wavelength of 281 nm. The relative response factor values of (R*)-2-( benzylamino)-1-((S*)-6-fluorochroman-2-yl) ethanol ((R x S*) NBV-), (R)-1-((R)-6-fluorochroman-2-yl)-2-((S)-2-((S)-6-fluoro-chroman-2-yl)-2-hydroxyethyl-amino) ethanol ((RRSS) NBV-3), 1-(chroman-2-yl)-2-(2-(6-fluorochroman-2-yl)-2-hydroxyethyl amino) ethanol (monodesfluoro impurity), (S)-1-((R)-6-fluorochroman-2-yl)-2-((R)-2 (S*)-6-fluoro-chroman-2-yl)-2-hydroxyethylamino) ethanol hydrochloride ((RSRS) NBV-3) and (R*)-1-((S*)-6-fluorochroman-2-yl)-2-((S*)-2-((S*)-6-fluoro-chroman-2-yl)-2-hydroxyethylamino) ethanol ((R* S* S* S*) NBV-2) were 0.65, 0.91, 0.68, 0.92 and 0.91 respectively. Nebivolol formulation sample was subjected to the stress conditions of acid, base, oxidative, hydrolytic, thermal, humidity and photolytic degradation. Nebivolol was found to degrade significantly under peroxide stress condition. The degradation products were well resolved from nebivolol and its impurities. The peak purity test results confirmed that the nebivolol peak was homogenous and pure in all stress samples and the mass balance was found to be more than 98%, thus proving the stability-indicating power of the method. The developed method was validated according to International Conference on Hormonization (ICH) guidelines with respect to specificity, linearity, limits of detection and quantification, accuracy, precision and robustness.

  3. A Validated Stability-Indicating RP-UPLC Method for Simultaneous Determination of Desloratadine and Sodium Benzoate in Oral Liquid Pharmaceutical Formulations.

    PubMed

    Kumar, Navneet; Sangeetha, Dhanaraj; Reddy, Pingili Sunil; Prakash, Lakkireddy

    2012-01-01

    A novel, sensitive and selective stability-indicating gradient reverse phase ultra performance liquid chromatographic method was developed and validated for the quantitative determination of desloratadine and sodium benzoate in pharmaceutical oral liquid formulation. The chromatographic separation was achieved on Acquity BEH C8 (100 mm × 2.1 mm) 1.7 μm column by using mobile phase containing a gradient mixture of solvent A (0.05 M KH(2)PO(4) and 0.07 M triethylamine, pH 3.0) and B (50:25:25 v/v/v mixture of acetonitrile, methanol and water) at flow rate of 0.4 mL/min. Column temperature was maintained at 40°C and detection was carried out at a wavelength of 272 nm. The described method shows excellent linearity over a range of 0.254 μg/mL to 76.194 μg/mL for desloratadine and 1.006 μg/mL to 301.67 μg/mL for sodium benzoate. The correlation coefficient for desloratadine and sodium benzoate was more than 0.999. To establish stability-indicating capability of the method, drug product was subjected to the stress conditions of acid, base, oxidative, hydrolytic, thermal and photolytic degradation. The degradation products were well resolved from desloratadine and sodium benzoate. The developed method was validated as per international ICH guidelines with respect to specificity, linearity, LOD, LOQ, accuracy, precision and robustness.

  4. Stability indicating LC method for rapid determination of related substances of O-desmethyl venlafaxine in active pharmaceutical ingredients and pharmaceutical formulations.

    PubMed

    Rao, Karri Visweswara; Reddy, Kesareddy Padmaja; Kumar, Yelavarthi Ravindra

    2014-01-01

    A simple, precise and accurate stability-indicating reversed phase-high performance liquid chromatography method was developed for the quantitative determination of O-desmethyl venlafaxine (ODV) and its related substances in active pharmaceutical ingredient and pharmaceutical formulation. The method was developed using YMC-pack ODS-A (150 × 4.6 mm, 3 μm) column with mobile phase containing a gradient mixture of solvents A and B. Solvent A contained a mixture of buffer and acetonitrile in the ratio of 85:15 (v/v). The buffer consisted of 10 mM potassium dihydrogen phosphate and 2 mM 1-octane sulfonic acid sodium salt (pH adjusted to 6.0 by using diluted potassium hydroxide solution). Solvent B contained a mixture of water and acetonitrile in the ratio of 20:80 (v/v). The eluted compounds were monitored at 230 nm. ODV and its six impurities were well separated within 14 min run time. It was subjected under the stress conditions of oxidative, acid, base, water, thermal and photolytic degradation. It was sensitive towards acidic, basic, oxidative and water stress conditions, stable in photolytic and thermal degradation conditions. The degradation products were well resolved from main peak and its impurities, the mass balance in each case was >99.0%, proving the stability-indicating power of the method. The developed method was validated as per International Conference on Harmonization (ICH) guidelines with respect to its specificity, linearity (correlation coefficient >0.9996), limit of detection, limit of quantification, accuracy (recovery range 97.1-103.2%), precision (% relative standard deviation ≤1.9%) and robustness.

  5. Development and validation of a stability indicating method for S-carboxymethyl-L-cysteine and related degradation products in oral syrup formulation.

    PubMed

    Fanigliulo, Ameriga; De Filippis, Piero; Curcuruto, Ornella; Repeto, Paolo; Roveda, Davide; Hartenstein, Matthew; Adams, Erwin; Cabooter, Deirdre

    2015-11-10

    A stability-indicating method for the determination of S-carboxymethyl-L-cysteine and related degradation impurities in Exputex® 250mg/5mL syrup was developed in anion-exchange liquid chromatography mode. A forced degradation study supported the method development to ensure stability indicating conditions. Aqueous solutions of the active pharmaceutical ingredient and syrup samples at different pH-values were stress-tested in different thermal, light exposure and headspace conditions. One degradation product was detected in thermal stress studies at 60°C and 80°C in the pH range 5.0-7.0 and was identified by mass spectrometry as 5-oxo-thiomorpholine-3-carboxylic acid (lactam of carbocysteine). A second degradation product was only generated in moderately strong oxidizing conditions (0.5% H2O2 aqueous solution) and was identified as S-carboxymethyl-L-cysteine-(R/S)-sulphoxide (carbocysteine sulphoxide). The method was developed on a Zorbax SAX column, in isocratic mode. The mobile phase consisted of 200mM phosphate solution at pH 4.0 and acetonitrile (50:50 v/v) and UV detection was performed at a wavelength of 205nm. The method was linear for carbocysteine (R>0.9982) over a concentration range of 2.5-50μg/mL and 0.4-0.6mg/mL. Linearity for the impurities was shown from the LOQ to 50μg/mL. Specificity was verified and accuracy demonstrated for the active ingredient and its degradation products in syrup samples at 3 levels around their respective specification limits. Repeatability, intermediate precision and inter-laboratory reproducibility were assessed on three commercial batches, analyzed in triplicate by two operators at both the transferring and the receiving site and demonstrated a successful method transfer to the manufacturing quality control laboratory.

  6. Development and validation of a rapid stability indicating HPLC-method using monolithic stationary phase and two spectrophotometric methods for determination of antihistaminic acrivastine in capsules.

    PubMed

    Gouda, Ayman A; Hashem, Hisham; Jira, Thomas

    2014-09-15

    Simple, rapid and accurate high performance liquid chromatographic (HPLC) and spectrophotometric methods are described for determination of antihistaminic acrivastine in capsules. The first method (method A) is based on accurate, sensitive and stability indicating chromatographic separation method. Chromolith® Performance RP-18e column, a relatively new packing material consisting of monolithic rods of highly porous silica, was used as stationary phase applying isocratic binary mobile phase of ACN and 25 mM NaH2PO4 pH 4.0 in the ratio of 22.5:77.5 at flow rate of 5.0 mL/min and 40°C. A diode array detector was used at 254 nm for detection. The elution time of acrivastine was found to be 2.080±0.032. The second and third methods (methods B and C) are based on the oxidation of acrivastine with excess N-bromosuccinimide (NBS) and determination of the unconsumed NBS with, metol-sulphanilic acid (λmax: 520 nm) or amaranth dye (λmax: 530 nm). The reacted oxidant corresponds to the drug content. Beer's law is obeyed over the concentration range 1.563-50, 2.0-20 and 1.0-10 μg mL(-1) for methods A, B and C, respectively. The limits of detection and quantitation were 0.40, 0.292 and 0.113 μg mL(-1) and 0.782, 0.973 and 0.376 μg mL(-1) for methods A, B and C, respectively. The HPLC method was validated for system suitability, linearity, precision, limits of detection and quantitation, specificity, stability and robustness. Stability tests were done through exposure of the analyte solution for four different stress conditions and the results indicate no interference of degradants with HPLC-method. The proposed methods was favorably applied for determination of acrivastine in capsules formulation. Statistical comparison of the obtained results from the analysis of the studied drug to those of the reported method using t- and F-tests showed no significant difference between them.

  7. Development and validation of a rapid stability indicating HPLC-method using monolithic stationary phase and two spectrophotometric methods for determination of antihistaminic acrivastine in capsules

    NASA Astrophysics Data System (ADS)

    Gouda, Ayman A.; Hashem, Hisham; Jira, Thomas

    2014-09-01

    Simple, rapid and accurate high performance liquid chromatographic (HPLC) and spectrophotometric methods are described for determination of antihistaminic acrivastine in capsules. The first method (method A) is based on accurate, sensitive and stability indicating chromatographic separation method. Chromolith® Performance RP-18e column, a relatively new packing material consisting of monolithic rods of highly porous silica, was used as stationary phase applying isocratic binary mobile phase of ACN and 25 mM NaH2PO4 pH 4.0 in the ratio of 22.5:77.5 at flow rate of 5.0 mL/min and 40 °C. A diode array detector was used at 254 nm for detection. The elution time of acrivastine was found to be 2.080 ± 0.032. The second and third methods (methods B and C) are based on the oxidation of acrivastine with excess N-bromosuccinimide (NBS) and determination of the unconsumed NBS with, metol-sulphanilic acid (λmax: 520 nm) or amaranth dye (λmax: 530 nm). The reacted oxidant corresponds to the drug content. Beer’s law is obeyed over the concentration range 1.563-50, 2.0-20 and 1.0-10 μg mL-1 for methods A, B and C, respectively. The limits of detection and quantitation were 0.40, 0.292 and 0.113 μg mL-1 and 0.782, 0.973 and 0.376 μg mL-1 for methods A, B and C, respectively. The HPLC method was validated for system suitability, linearity, precision, limits of detection and quantitation, specificity, stability and robustness. Stability tests were done through exposure of the analyte solution for four different stress conditions and the results indicate no interference of degradants with HPLC-method. The proposed methods was favorably applied for determination of acrivastine in capsules formulation. Statistical comparison of the obtained results from the analysis of the studied drug to those of the reported method using t- and F-tests showed no significant difference between them.

  8. A new, rapid, stability-indicating UPLC method for separation and determination of impurities in amlodipine besylate, valsartan and hydrochlorothiazide in their combined tablet dosage form.

    PubMed

    Vojta, Jiří; Jedlička, Aleš; Coufal, Pavel; Janečková, Lucie

    2015-05-10

    A new rapid stability-indicating UPLC method for separation and determination of impurities in amlodipine besylate, valsartan and hydrochlorothiazide in their combined tablet dosage form was developed. The separation of Ph. Eur. related substances of amlodipine besylate (A, B, D, E, F, G), hydrochlorothiazide (A, B, C), valsartan (B, C), two other valsartan impurities (S)-2-(N-{[2'-cyanobiphenyl-4-yl]methyl}pentanamido)-3-methylbutanoic acid and (S)-3-methyl-2-{[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methylamino}butanoic acid and several unknown impurities was achieved by reversed phase liquid chromatography with UV detection. The detection wavelengths were set as follows: 225nm for valsartan, its impurities and for the impurity D of amlodipine, 271nm for hydrochlorothiazide and its impurities and 360nm for amlodipine and its impurities except for impurity D. Zorbax Eclipse C8 RRHD (100mm×3.0mm, 1.8μm) was used as a separation column and the analytes were eluted within 11min by a programmed gradient mixture of 0.01M phosphate buffer pH 2.5 and acetonitrile. The method was successfully validated in accordance to the International Conference of Harmonization (ICH) guidelines for amlodipine besylate and its impurity D, valsartan and its impurity C and hydrochlorothiazide and its impurities A, B and C. The triple-combined tablets were exposed to thermal, higher humidity, acid, alkaline, oxidative and photolytic stress conditions. Stressed samples were analyzed by the proposed method. All the significant degradation products and impurities were satisfactory separated from each other and from the principal peaks of drug substances. The peak purity test complied for peaks of amlodipine, valsartan and hydrochlorothiazide in all the stressed samples and indicated no co-elution of degradation products. The method was found to be precise, linear, accurate, sensitive, specific, robust and stability-indicating and could be used as a routine purity test method for amlodipine

  9. Stability-indicating UPLC method for determination of Imatinib Mesylate and their degradation products in active pharmaceutical ingredient and pharmaceutical dosage forms.

    PubMed

    Nageswari, A; Reddy, K V S R Krishna; Mukkanti, K

    2012-07-01

    A simple, precise, accurate stability-indicating gradient reverse phase ultra-performance liquid chromatographic (RP-UPLC) method was developed for quantitative determination of purity of Imatinib Mesylate (IMM) drug substance and drug products in the presence of its process related impurities, and degradation products. The proposed RP-UPLC method utilizes Acquity UPLC BEH 50-mm, 2.1mm and 1.7 μm C-18 column at 30 °C, with a gradient program of 9.0 min at a flow rate of 0.3 mL/min. The compounds of interest were monitored at 237 nm. Resolution for Imatinib and eight related components was found to be greater than 1.5 for any pair of components. The correlation coefficients (r(2)>0.9990) obtained indicate clear correlations between the concentrations and their peak areas for the investigated compounds. RSD obtained for the repeatability and intermediate precision experiments, was less than 5.0%. Accuracy of the method was further ascertained by performing recovery studies through spiking experiments. The drug substance was subjected to hydrolytic, oxidative, photolytic and thermal stress conditions as per ICH. The developed method was validated according to the current ICH guidelines for specificity, limit of detection, limit of quantitation, linearity, accuracy, precision, ruggedness and robustness. The method is also suitable for the assay determination of IMM in pharmaceutical dosage forms.

  10. Development of a stability-indicating RP-LC method for the separation of a critical pair of impurities and their degradants in zafirlukast.

    PubMed

    Thiyagarajan, Thilak Kumar; Abdul Hakeem, Jamal Abdul Nasser; Baksam, Vijayakumar

    2012-01-01

    A high-throughput reverse-phase liquid chromatographic (RP-LC) method is developed for the quantification of zafirlukast and its related impurities in drug substance. The separation of known impurities is accomplished using a short (50 mm) LC column with sub-2-µm particle size in a relatively short run-time. A linear gradient elution involves ammonium formate and acetonitrile as mobile phase. The critical impurity pair is the meta and para isomers of zafirlukast, which are known to be potential impurities of zafirlukast, whose resolution is sensitive to pH. The stability-indicating capability of the developed method is demonstrated using forced degradation samples from stress conditions such as hydrolysis, oxidation, thermal and photolytic degradation. The developed RP-LC method is validated in accordance with International Conference on Harmonization requirements. The results from the validation study indicate that this RP-LC method can be used for the determination of synthetic and degradation impurities in regular quality control analysis for the drug substance.

  11. Least-Squares Regression and Spectral Residual Augmented Classical Least-Squares Chemometric Models for Stability-Indicating Analysis of Agomelatine and Its Degradation Products: A Comparative Study.

    PubMed

    Naguib, Ibrahim A; Abdelrahman, Maha M; El Ghobashy, Mohamed R; Ali, Nesma A

    2016-01-01

    Two accurate, sensitive, and selective stability-indicating methods are developed and validated for simultaneous quantitative determination of agomelatine (AGM) and its forced degradation products (Deg I and Deg II), whether in pure forms or in pharmaceutical formulations. Partial least-squares regression (PLSR) and spectral residual augmented classical least-squares (SRACLS) are two chemometric models that are being subjected to a comparative study through handling UV spectral data in range (215-350 nm). For proper analysis, a three-factor, four-level experimental design was established, resulting in a training set consisting of 16 mixtures containing different ratios of interfering species. An independent test set consisting of eight mixtures was used to validate the prediction ability of the suggested models. The results presented indicate the ability of mentioned multivariate calibration models to analyze AGM, Deg I, and Deg II with high selectivity and accuracy. The analysis results of the pharmaceutical formulations were statistically compared to the reference HPLC method, with no significant differences observed regarding accuracy and precision. The SRACLS model gives comparable results to the PLSR model; however, it keeps the qualitative spectral information of the classical least-squares algorithm for analyzed components.

  12. A Robust Liquid Chromatographic Method for Confirmation of Drug Stability of Azithromycin in Bulk Samples, Tablets and Suspensions

    PubMed Central

    Okaru, Alex O.; Abuga, Kennedy O.; Kamau, Franco N.; Ndwigah, Stanley N.; Lachenmeier, Dirk W.

    2017-01-01

    A simple, isocratic and robust RP-HPLC method for the analysis of azithromycin was developed, validated and applied for the analysis of bulk samples, tablets and suspensions. The optimum chromatographic conditions for separation were established as a mobile phase comprised of acetonitrile-0.1 M KH2PO4 pH 6.5–0.1 M tetrabutyl ammonium hydroxide pH 6.5-water (25:15:1:59 v/v/v/v) delivered at a flow rate of 1.0 mL/min. The stationary phase consisted of reverse-phase XTerra® (250 mm × 4.6 mm i.d., 5 µm particle size) maintained at a temperature of 43 °C with a UV detection at 215 nm. The method was found to be linear in the range 50%–150% (r2 = 0.997). The limits of detection and quantification were found to be 0.02% (20 µg) and 0.078% (78 µg), respectively, with a 100.7% recovery of azithromycin. Degradation products of azithromycin in acidic and oxidative environments at 37 °C were resolved from the active pharmaceutical ingredient and thus the method is fit for the purpose of drug stability confirmation. PMID:28245574

  13. Stability-indicating RP-LC method for determination of azilsartan medoxomil and chlorthalidone in pharmaceutical dosage forms: application to degradation kinetics.

    PubMed

    Ebeid, Walid M; Elkady, Ehab F; El-Zaher, Asmaa A; El-Bagary, Ramzia I; Patonay, Gabor

    2014-10-01

    A RP-LC method was developed and validated for simultaneous determination of the active components, azilsartan medoxomil (AZL) and chlorthalidone (CLT), in their novel antihypertensive combined recipe. The chromatographic separation was achieved on an Eclipse XDB-C18 (4.6 × 150 mm, 5 μm) column using a mobile phase consisting of methanol/potassium hydrogen phosphate buffer (pH 8, 0.05 M) (40:60, v/v) in isocratic mode. The flow rate was maintained at 0.8 mL min(-1) at ambient temperature. Detection was carried out at 210 nm. The method was validated according to the ICH guidelines. Linearity, accuracy, and precision were satisfactory over the concentration range of 5.0-50.0 and 2.5-25.0 μg mL(-1) for AZL and CLT, respectively (r (2) = 0.9999). LODs for AZL and CLT were 0.90 and 0.32 μg mL(-1), whereas LOQs were 2.72 and 0.98 μg mL(-1), respectively. Both drugs were subjected to forced degradation studies under hydrolysis (neutral, acidic, and alkaline), oxidative, and photolytic extensive stress conditions. The proposed method is stability indicating by the resolution of the investigated drugs from their degradation products. Moreover, the kinetics of the acidic degradation of AZL as well as the kinetics of the alkaline degradation of CLT were investigated. Arrhenius plots were constructed and the apparent first-order rate constants, half-life times, shelf-life times, and the activation energies of the degradation processes were calculated. The method was successfully applied for the determination of the studied drugs simultaneously in their coformulated tablet. The developed method is specific and stability indicating for the quality control and routine analysis of the cited medications in their pharmaceutical preparations.

  14. Solid-state stability of spray-dried insulin powder for inhalation: chemical kinetics and structural relaxation modeling of Exubera above and below the glass transition temperature.

    PubMed

    Sadrzadeh, Negar; Miller, Danforth P; Lechuga-Ballesteros, David; Harper, Nancy J; Stevenson, Cynthia L; Bennett, David B

    2010-09-01

    The effect of temperature on the chemical stability of an amorphous spray-dried insulin powder formulation (Exubera) was evaluated in the solid state at constant moisture content. The chemical stability of the powder was assessed using reversed-phase high-performance liquid chromatography (RP-HPLC) and high-performance-size exclusion chromatography (HP-SEC). The major degradants in spray-dried insulin produced during heat stressing were identified as A21-desamidoinsulin (A21) and high molecular weight protein (HMWP). As expected, the rates of formation of A21 and HMWP were observed to increase with temperature. A stretched-time kinetic model (degradation rate is proportional to the square root of time) was applied to the degradant profiles above and below the glass transition temperature (T(g)) and apparent reaction rate constants were determined. Below T(g), isothermal enthalpy of relaxation measurements were used to assess the effect of temperature on molecular mobility. The formation of A21 and HMWP was found to follow an Arrhenius temperature dependence above and below the T(g). Comparison of reaction rate constants to those estimated from structural relaxation experiments suggests that the reaction pathways to form A21 and HMWP below the T(g) may be coupled with the molecular motions involved in structural relaxation.

  15. Removal of Fecal Indicators, Pathogenic Bacteria, Adenovirus, Cryptosporidium and Giardia (oo)cysts in Waste Stabilization Ponds in Northern and Eastern Australia.

    PubMed

    Sheludchenko, Maxim; Padovan, Anna; Katouli, Mohammad; Stratton, Helen

    2016-01-02

    Maturation ponds are used in rural and regional areas in Australia to remove the microbial loads of sewage wastewater, however, they have not been studied intensively until present. Using a combination of culture-based methods and quantitative real-time PCR, we assessed microbial removal rates in maturation ponds at four waste stabilization ponds (WSP) with (n = 1) and without (n = 3) baffles in rural and remote communities in Australia. Concentrations of total coliforms, E. coli, enterococci, Campylobacter spp., Salmonella spp., F+ RNA coliphage, adenovirus, Cryptosporidium spp. and Giardia (oo) cysts in maturation ponds were measured at the inlet and outlet. Only the baffled pond demonstrated a significant removal of most of the pathogens tested and therefore was subjected to further study by analyzing E. coli and enterococci concentrations at six points along the baffles over five sampling rounds. Using culture-based methods, we found a decrease in the number of E. coli and enterococci from the initial values of 100,000 CFU per 100 mL in the inlet samples to approximately 1000 CFU per 100 mL in the outlet samples for both bacterial groups. Giardia cysts removal was relatively higher than fecal indicators reduction possibly due to sedimentation.

  16. Collapse of the sea surface stability during the Miocene to Quartenary in the Western Pacific Ocean, indicated by Discoaster abundance and Coccolith size change

    NASA Astrophysics Data System (ADS)

    Sato, T.; Pratiwi, S. D.; Farida, M.

    2013-12-01

    We describe in detail the middle Miocene to Pleistocene paleoceanography of the Western Pacific Ocean based on calcareous nannofossils. Abundantly occurrence of discoasters, which indicates the stable sea surface stratification and the development of thermo- and nutri-cline, are found in the interval from NN2 to NN4 zones of the early Miocene. The relative abundance of discoaster is decreased in the NN4-5 zone and it changed to very rare above NN10 (B in Fig.1). These characteristics are found in both Sites 805 and 782. Focusing to the mean size of Reticulofenestra species, it decreased at NN4-5 zone (A in Fig 2), and lower part of NN11 (B in Fig. 2). The presence of larger size Reticulofenestra species also show the oligotrophic conditions of sea surface with thermocline. On the basis of these results, the collapse of the stability of the sea surface stratification in the Western Pacific Ocean progressed throughout the Miocene to Quaternary. As the results, nutrient conditions of sea surface in these area were changed in steps from oligotrophic to eutrophic conditions at NN4-5 and lower part of NN11 (A and B in Fig. 2). These datum related to collapse of sea surface conditions, is cleary correlated to the timing of the end of Mid-Miocene Climatic Optimum (A) and the intensify of the Asian Monsoon (B; Fig. 2).

  17. Development of a stability-indicating HPLC method of etifoxine with characterization of degradation products by LC-MS/TOF, 1H and 13C NMR.

    PubMed

    Djabrouhou, Nadia; Guermouche, Moulay-Hassane

    2014-11-01

    This paper describes a new LC-MS/TOF method for the degradation products determination when Etifoxine (ETI) is submitted to different stress conditions. Chromatography is performed by using Kromasil C18 column (250mm×4.6mm, 5μm particle size). The selected mobile phase consists of formate buffer 0.02M, pH 3 and methanol (70/30, v/v). ETI is submitted to oxidative, acidic, basic, hydrolytic, thermal and UV light degradations. Detection is made at 254nm by photodiode array detector and mass spectrometry. A number of degradation products (DPs) called DPA, DPB, DPC and DPD are found depending on the stress; DPA with heat, DPA and DPB in acidic media or under UV-light; DPA, DPB and DPC under basic stress; DPA, DPB, DPC and DPD with oxidation. LC-MS/TOF is used to characterize the four DPs of ETI resulting from different stress conditions. (1)H and (13)C NMR are used to confirm the DP structures. The ETI fragmentation pathway is proposed. The method is validated with reference to International Conference on Harmonization guidelines and ETI are selectively determined in presence of its DPs, demonstrating its stability-indicating nature. Finally, for the validation step, specificity, linearity, accuracy and precision are determined for ETI and its DPs.

  18. A versatile, stability-indicating and high-throughput ultra-fast liquid chromatography method for the determination of isoflavone aglycones in soybeans, topical formulations, and permeation assays.

    PubMed

    Nemitz, Marina C; Yatsu, Francini K J; Bidone, Juliana; Koester, Letícia S; Bassani, Valquiria L; Garcia, Cássia V; Mendez, Andreas S L; von Poser, Gilsane L; Teixeira, Helder F

    2015-03-01

    There is a growing interest in the pharmaceutical field concerning isoflavones topical delivery systems, especially with regard to their skin care properties and antiherpetic activity. In this context, the present work describes an ultra-fast liquid chromatography method (UFLC) for determining daidzein, glycitein, and genistein in different matrices during the development of topical systems containing isoflavone aglycones (IA) obtained from soybeans. The method showed to be specific, precise, accurate, and linear (0.1 to 5 µg mL(-1)) for IA determination in soybean acid extract, IA-rich fraction obtained after the purification process, IA loaded-nanoemulsions, and topical hydrogel, as well as for permeation/retention assays in porcine skin and porcine esophageal mucosa. The matrix effect was determined for all complex matrices, demonstrating low effect during the analysis. The stability indicating UFLC method was verified by submitting IA to acidic, alkaline, oxidative, and thermal stress conditions, and no interference of degradation products was detected during analysis. Mass spectrometry was performed to show the main compounds produced after acid hydrolysis of soybeans, as well as suggest the main degradation products formed after stress conditions. Besides the IA, hydroxymethylfurfural and ethoxymethylfurfural were produced and identified after acid hydrolysis of the soybean extract and well separated by the UFLC method. The method's robustness was confirmed using the Plackett-Burman experimental design. Therefore, the new method affords fast IA analysis during routine processes, extract purification, products development, and bioanalytical assays.

  19. Development and validation of a simple stability-indicating high performance liquid chromatographic method for the determination of miconazole nitrate in bulk and cream formulations.

    PubMed

    De Zan, María M; Cámara, María S; Robles, Juan C; Kergaravat, Silvina V; Goicoechea, Héctor C

    2009-08-15

    A simple and stability-indicating high performance liquid chromatographic method was developed and validated for the determination of miconazole nitrate in bulk and cream preparations. The extraction step for cream samples consisted in a warming, cooling and centrifugation procedure that assures the elimination of the lipophilic matrix component, in order to avoid further precipitation in the chromatographic system. Separation was achieved on a ZORBAX Eclipse XDB - C18 (4.6 mm x 150 mm, 5 microm particle size) column, using a mobile phase consisting of water, methanol and acetonitrile, in a flow and solvent gradient elution for 15 min. The column was maintained at 25 degrees C and 10 microL of solutions were injected. UV detection was performed at 232 nm, although employment of a diode array detector allowed selectivity confirmation by peak purity evaluation. The method was validated reaching satisfactory results for selectivity, precision and accuracy. Degradation products in naturally aged samples could be simultaneously evaluated, without interferences in the quantitative analysis.

  20. Spectrofluorimetric and spectrophotometric stability-indicating methods for determination of some oxicams using 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl).

    PubMed

    Taha, Elham Anwer; Salama, Nahla Nour; Fattah, Laila El-Sayed Abdel

    2006-05-01

    Two sensitive and selective spectrofluorimetric and spectrophotometric stability-indicating methods have been developed for the determination of some non-steroidal anti-inflammatory oxicam derivatives namely lornoxicam (Lx), tenoxicam (Tx) and meloxicam (Mx) after their complete alkaline hydrolysis. The methods are based on derivatization of alkaline hydrolytic products with 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl). The products showed an absorption maximum at 460 nm for the three studied drugs and fluorescence emission peak at 535 nm in methanol. The color was stable for at least 48 h. The optimum conditions of the reaction were investigated and it was found that the reaction proceeds quantitatively at pH 8, after heating in a boiling water bath for 30 min. The methods were found to be linear in the ranges of 1-10 microg ml(-1) for Lx and Tx and 0.5-4.0 microg ml(-1) for Mx for spectrophotometric method, while 0.05-1.0 microg ml(-1) for Lx and Tx and 0.025-0.4 microg ml(-1) for Mx for the spectrofluorimetric method. The validity of the methods was assessed according to USP guidelines. Statistical analysis of the results revealed high accuracy and good precision. The suggested procedures could be used for the determination of the above mentioned drugs in pure and dosage forms as well as in the presence of their degradation products.

  1. Validated stability-indicating liquid chromatographic method for the determination of ribavirin in the presence of its degradation products: application to degradation kinetics.

    PubMed

    Belal, Fathalla; Sharaf El-Din, Mohie K; Eid, Manal I; El-Gamal, Rania M

    2015-04-01

    Ribavirin was found to be liable to acidic, alkaline, oxidative and photolytic degradation. Hence, a simple, sensitive and stability-indicating reversed-phase liquid chromatographic method was developed and validated for the determination of ribavirin in the presence of its degradation products. The analysis was carried out on an ODS C18 (250 × 4.6 mm i.d.) stainless steel column using a mobile phase consisting of 0.02 M potassium dihydrogen phosphate. The analysis was performed at ambient temperature with a flow rate of 1 mL/min and UV detection at 207 nm. Pyridoxine hydrochloride was used as an internal standard. The method showed good linearity over the concentration range of 2.0-40 µg/mL with limit of detection of 0.34 µg/mL and limit of quantification of 1.03 µg/mL. The suggested method was successfully applied for the analysis of ribavirin in its commercial capsules. Statistical evaluation and comparison of the data obtained by the proposed and comparison method revealed good accuracy and precision of the proposed method. The drug was exposed to forced alkaline, acidic, oxidative and photolytic degradation according to the ICH guidelines. Moreover, the method was utilized to investigate the kinetics of alkaline and acidic degradation of the drug. The apparent first-order rate constants, half-life times and activation energies of the degradation process were calculated.

  2. Acetylation mimics within individual core histone tail domains indicate distinct roles in regulating the stability of higher-order chromatin structure.

    PubMed

    Wang, Xiaodong; Hayes, Jeffrey J

    2008-01-01

    Nucleosome arrays undergo salt-dependent self-association into large oligomers in a process thought to recapitulate essential aspects of higher-order tertiary chromatin structure formation. Lysine acetylation within the core histone tail domains inhibits self-association, an effect likely related to its role in facilitating transcription. As acetylation of specific tail domains may encode distinct functions, we investigated biochemical and self-association properties of model nucleosome arrays containing combinations of native and mutant core histones with lysine-to-glutamine substitutions to mimic acetylation. Acetylation mimics within the tail domains of H2B and H4 caused the largest inhibition of array self-association, while modification of the H3 tail uniquely affected the stability of DNA wrapping within individual nucleosomes. In addition, the effect of acetylation mimics on array self-association is inconsistent with a simple charge neutralization mechanism. For example, acetylation mimics within the H2A tail can have either a positive or negative effect on self-association, dependent upon the acetylation state of the other tails and nucleosomal repeat length. Finally, we demonstrate that glutamine substitutions and lysine acetylation within the H4 tail domain have identical effects on nucleosome array self-association. Our results indicate that acetylation of specific tail domains plays distinct roles in the regulation of chromatin structure.

  3. Removal of Fecal Indicators, Pathogenic Bacteria, Adenovirus, Cryptosporidium and Giardia (oo)cysts in Waste Stabilization Ponds in Northern and Eastern Australia

    PubMed Central

    Sheludchenko, Maxim; Padovan, Anna; Katouli, Mohammad; Stratton, Helen

    2016-01-01

    Maturation ponds are used in rural and regional areas in Australia to remove the microbial loads of sewage wastewater, however, they have not been studied intensively until present. Using a combination of culture-based methods and quantitative real-time PCR, we assessed microbial removal rates in maturation ponds at four waste stabilization ponds (WSP) with (n = 1) and without (n = 3) baffles in rural and remote communities in Australia. Concentrations of total coliforms, E. coli, enterococci, Campylobacter spp., Salmonella spp., F+ RNA coliphage, adenovirus, Cryptosporidium spp. and Giardia (oo) cysts in maturation ponds were measured at the inlet and outlet. Only the baffled pond demonstrated a significant removal of most of the pathogens tested and therefore was subjected to further study by analyzing E. coli and enterococci concentrations at six points along the baffles over five sampling rounds. Using culture-based methods, we found a decrease in the number of E. coli and enterococci from the initial values of 100,000 CFU per 100 mL in the inlet samples to approximately 1000 CFU per 100 mL in the outlet samples for both bacterial groups. Giardia cysts removal was relatively higher than fecal indicators reduction possibly due to sedimentation. PMID:26729150

  4. Development of a Stability-Indicating RP-UPLC Method for Rapid Determination of Metaxalone and its Degradation Products in Solid Oral Dosage Form

    PubMed Central

    Trivedi, Rakshit Kanubhai; Patel, Mukesh C.

    2012-01-01

    A simple, sensitive and reproducible reversed phase ultra performance liquid chromatography (RP-UPLC) coupled with a photodiode array detector method was developed for the quantitative determination of metaxalone (META) in pharmaceutical dosage forms. The method is applicable to the quantification of related substances and assay of drug product. Chromatographic separation was achieved on an Acquity® HSS-T3 (100 mm x 2.1 mm, 1.7 μm) column. The optimized isocratic mobile phase consists of a mixture of water, methanol, acetonitrile and triethylamine in the ratio of 50:25:25:0.1 % v/v (pH adjusted to 6.3 with orthophosphoric acid). The eluted compounds were monitored at 230 nm for META assay and 205 nm for related substances, the flow rate was 0.3 mL/min, and the column oven temperature was maintained at 45°C. The developed method separated META from its two known and two unknown impurities within 6.0 min. Metaxalone was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. Metaxalone was found to degrade significantly in base stress condition, degrade slightly in oxidative stress condition and remain stable in acid, hydrolytic, thermal and photolytic degradation conditions. All impurities were well resolved from each other and from the main peak, showing the stability-indicating power of the method. The developed method was validated as per International Conference on Harmonization (ICH) guidelines. PMID:22896822

  5. Coupled solid phase extraction and microparticle-based stability and purity-indicating immunosensor for the determination of recombinant human myelin basic protein in transgenic milk.

    PubMed

    Al-Ghobashy, Medhat A; Williams, Martin A K; Laible, Götz; Harding, David R K

    2013-05-15

    An optical immunosensor was developed and validated on the surface of microparticles for the determination of a biopharmaceutical protein. The recombinant human myelin basic protein (rhMBP) was produced in milk of transgenic cows as a His-tagged fusion protein. Previous work indicated exclusive association of rhMBP with milk casein micelles that hindered direct determination of the protein in milk. In this work, a solid phase extraction using a cation exchange matrix was developed in order to liberate rhMBP from casein micelles. A sandwich-type immunoassay was then used for in-process monitoring of the full-length protein in the presence of major milk proteins. The assay was successfully employed for detection of ultra-traces of rhMBP (LOD=6.04 ng mL(-1)≈0.3 n mol L(-1)) and for quantitative determination over a wide concentration range (10.00-10,000.00 ng mL(-1)). The assay was able also to detect the rhMBP in the presence of its human counterpart that lacks the His-tag. The high sensitivity along with the ability of the assay to determine the full length protein enabled monitoring of the stability of rhMBP. The testing protocol is particularly useful for intrinsically unstructured proteins that are extremely sensitive to proteolysis and lack a traceable enzymatic activity. This immunosensor provides a specific, ultrasensitive high throughput tool for in-process monitoring in biopharmaceutical industry.

  6. Development and validation of a stability-indicating RP-UPLC method for the quantitative analysis of nabumetone in tablet dosage form.

    PubMed

    Sethi, Neha; Anand, Ankit; Chandrul, Kaushal K; Jain, Garima; Srinivas, Kona S

    2012-02-01

    High efficiency and less run time are the basic requirements of high-speed chromatographic separations. To fulfill these requirements, a new separation technique, ultra-performance liquid chromatography (UPLC), has shown promising developments. A rapid, specific, sensitive, and precise reverse-phase UPLC method is developed for the determination of nabumetone in tablet dosage form. In this work, a new isocratic chromatographic method is developed. The newly developed method is applicable for assay determination of the active pharmaceutical ingredient. The chromatographic separation is achieved on a Waters Acquity BEH column (100 mm, i.d., 2.1 mm, 1.7 µm) within a short runtime of 2 min using a mobile phase of 5 mM ammonium acetate-acetonitrile (25:75, v/v), at a flow rate of 0.3 mL/min at an ambient temperature. Quantification is achieved with photodiode array detection at 230 nm, over the concentration range of 0.05-26 µg/mL. Forced degradation studies are also performed for nabumetone bulk drug samples to demonstrate the stability-indicating power of the UPLC method. Comparison of system performance with conventional high-performance liquid chromatography is made with respect to analysis time, efficiency, and sensitivity. The method is validated according to the ICH guidelines and is applied successfully for the determination of nabumetone in tablets.

  7. Stress Degradation Behavior of Atorvastatin Calcium and Development of a Suitable Stability-Indicating LC Method for the Determination of Atorvastatin, its Related Impurities, and its Degradation Products.

    PubMed

    Vukkum, Pallavi; Moses Babu, J; Muralikrishna, R

    2013-01-01

    A rapid, reversed-phase liquid chromatographic method was developed for the quantitative determination of Atorvastatin calcium, its related substances (12 impurities), and degradation impurities in bulk drugs. The chromatographic separation was achieved on a Zorbax Bonus-RP column by employing a gradient elution with water-acetonitrile-trifluoroacetic acid as the mobile phase in a shorter run time of 25 min. The flow rate was 1.0 mL/min and the detection wavelength was 245 nm. The drug substance was subjected to stress studies such as hydrolysis, oxidation, photolysis, and thermal degradation, and considerable degradation was observed in acidic hydrolysis, oxidative, thermal, and photolytic stress conditions. The formed degradation products were reported and were well-resolved from the Atorvastatin and its related substances. The stressed samples were quantified against a qualified reference standard and the mass balance was found to be close to 99.5% (w/w) when the response of the degradant was considered to be equal to the analyte (i.e. Atorvastatin), which demonstrates the stability-indicating capability of the method. The method was validated in agreement with ICH requirements. The method developed here was single and shorter (25 min method for the determination of all 12 related impurities of Atorvastatin and its degradation products), with clearly better resolution and higher sensitivity than the European (85 min method for the determination of six impurities) and United States pharmacopeia (115 min and 55 min, two different methods for the determination of six related substances).

  8. Forced degradation study to develop and validate stability-indicating RP-LC method for the determination of ciclesonide in bulk drug and metered dose inhalers.

    PubMed

    Elkady, Ehab F; Fouad, Marwa A

    2011-12-15

    A simple, selective and precise stability-indicating reversed-phase liquid chromatographic method was developed and validated for the determination of ciclesonide. Ciclesonide was subjected to acid and alkali hydrolysis, oxidation, thermal and photo-degradation. The degradation products were well separated from the pure drug. The method was based on isocratic elution of ciclesonide and its degradation products on reversed phase C18 column (250 mm × 4.6 mm, 10 μm) - Phenomenex using a mobile phase consisting of ethanol-water (70:30, v/v) at a flow rate of 1 mL min(-1). Quantitation was achieved with UV detection at 242 nm. Linearity, accuracy and precision were found to be acceptable over the concentration range of 5-200 μg mL(-1). Desisobutyryl-ciclesonide was prepared by selective alkaline hydrolysis of the ester and proved to be the main degradation product. The proposed method was successfully applied to the determination of ciclesonide in bulk and in its pharmaceutical preparation.

  9. Study of forced degradation behaviour of florfenicol by LC and LC-MS and development of a validated stability-indicating assay method.

    PubMed

    Mistiri, F; Louati, K; Grissa, O; Kallel, M; Safta, F

    2012-11-01

    A stability-indicating high performance liquid chromatography (HPLC) method was developed for the analysis of florfenicol in presence of its two available identified degradation products (thiamphenicol and chlorfenicol). The drug was subjected to different International Conference On Harmonisation (ICH) prescribed stress conditions (hydrolysis, oxidation and photolysis). The products formed under different stress conditions were investigated by liquid chromatography (LC) and liquid chromatography-mass spectrometry (LC-MS). The LC method involved a Knauwer Eurospher C18 thermostated column at 25°C; and ammonium acetate buffer 6.49mM (pH adjusted to 4.5)-methanol (70:30 v/v) as mobile phase. The flow rate and detection wavelength were 1ml/min and 225nm respectively. The drug showed instability under acidic, alkaline and photolytic stress conditions mainly in solution state form; however, it remains stable in solid state form and under oxidative stress conditions. The developed method was validated for linearity, precision, accuracy and specificity. The degradation products were characterized by LC-MS. Through the mass/ionization (m/z) values and fragmentation patterns, two principal degradation products listed in bibliography have been shown: the florfenicol amine and thiamphenicol. Based on the results, a more complete degradation pathway of the drug could be proposed.

  10. Stability-indicating LC assay for butenafine hydrochloride in creams using an experimental design for robustness evaluation and photodegradation kinetics study.

    PubMed

    Barth, Aline Bergesch; de Oliveira, Gabriela Bolfe; Malesuik, Marcelo Donadel; Paim, Clésio Soldatelli; Volpato, Nadia Maria

    2011-08-01

    A stability-indicating liquid chromatography method for the determination of the antifungal agent butenafine hydrochloride (BTF) in a cream was developed and validated using the Plackett-Burman experimental design for robustness evaluation. Also, the drug photodegradation kinetics was determined. The analytical column was operated with acetonitrile, methanol and a solution of triethylamine 0.3% adjusted to pH 4.0 (6:3:1) at a flow rate of 1 mL/min and detection at 283 nm. BTF extraction from the cream was done with n-butyl alcohol and methanol in ultrasonic bath. The performed degradation conditions were: acid and basic media with HCl 1M and NaOH 1M, respectively, oxidation with H(2)O(2) 10%, and the exposure to UV-C light. No interference in the BTF elution was verified. Linearity was assessed (r(2) = 0.9999) and ANOVA showed non-significative linearity deviation (p > 0.05). Adequate results were obtained for repeatability, intra-day precision, and accuracy. Critical factors were selected to examine the method robustness with the two-level Plackett-Burman experimental design and no significant factors were detected (p > 0.05). The BTF photodegradation kinetics was determined for the standard and for the cream, both in methanolic solution, under UV light at 254 nm. The degradation process can be described by first-order kinetics in both cases.

  11. A Single Gradient Stability-Indicating Reversed-Phase LC Method for the Estimation of Impurities in Omeprazole and Domperidone Capsules.

    PubMed

    Seshadri, Raja Kumar; Raghavaraju, Thummala Veera; Chakravarthy, Ivon Elisha

    2013-01-01

    A gradient reversed-phase liquid chromatographic (RP-LC) method was developed for the quantitative estimation of impurities in the pharmaceutical dosage form of Omeprazole and Domperidone capsules. The developed method is a stability-indicating test method for the estimation of impurities generated during the formulation and storage of Omeprazole and Domperidone capsules. The chromatographic separation was achieved on a column packed with octadecyl silane, having a column length of 250 mm and diameter of 4.6 mm with a particle size of 5 μm, and by following a gradient program using a combination of a monobasic potassium phosphate buffer (0.05M) and acetonitrile. Since the spectral properties were similar, both compounds' individual impurities were estimated at 285 nm. Forced degradation studies were performed on Omeprazole pellets (enteric coated) and Domperidone pellets (SR coated) encapsulated in size '1' hard gelatin capsules. Omeprazole and Domperidone were degraded using acid hydrolysis (0.1 N hydrochloric acid), base (0.1 N sodium hydroxide), oxidation (50% hydrogen peroxide), heat (105 °C), and UV light (254 nm). The established method was validated and found to be linear, accurate, precise, specific, robust, and rugged.

  12. Preparation and characterization of two new forced degradation products of letrozole and development of a stability-indicating RP-LC method for its determination.

    PubMed

    Elkady, Ehab Farouk; Fouad, Marwa Ahmed

    2015-11-01

    Two new hydrolytic products of letrozole were identified and proved to be true degradation products obtained by alkaline and acidic degradation of the drug. The acid and amide forms of the nitrile groups of letrozole were prepared and identified by IR and mass spectroscopic techniques. Subsequently, a simple, precise and selective stability-indicating RPLC method was developed and validated for the determination of letrozole in the presence of its degradation products. Letrozole was subjected to alkali and acid hydrolysis, oxidation, thermal degradation and photo-degradation. The degradation products were well isolated from letrozole. The chromatographic method was achieved using gradient elution of the drug and its degradation products on a reversed phase Zorbax Eclipse C18 column (100mm x 4.6mm, 3.5 μm) using a mobile phase consisting of 0.01M KH₂PO₄and methanol at a flow rate of 1 mL min⁻¹. Quantitation was achieved with UV detection at 230 nm. Linearity, accuracy and precision were found to be acceptable over the concentration range of 0.01-80 μgmL⁻¹. The proposed method was successfully applied to the determination of letrozole in bulk, plasma and in its pharmaceutical preparation.

  13. Development and validation of a stability-indicating micellar liquid chromatographic method for the determination of timolol maleate in the presence of its degradation products.

    PubMed

    Rizk, Mohamed S; Merey, Hanan A; Tawakkol, Shereen M; Sweilam, Mona N

    2015-04-01

    A stability-indicating micellar liquid chromatographic (MLC) method was developed and validated for the quantitative determination of timolol maleate (TM) in the presence of its degradation products resulting from accelerated degradation in a run time not more than 8 min. TM was subjected to stress conditions of hydrolysis (including alkaline, acidic and thermal hydrolysis) and oxidation. An isocratic, rapid and mobile phase saving the micellar LC method was developed with a BioBasic phenyl column (150 × 1.0 mm, 5 µm particle size) and a micellar mobile phase composed of 0.1 M sodium dodecyl sulfate, 10% of 1-propanol and 0.1% of triethylamine in 0.035 M ortho-phosphoric acid. The flow rate of the mobile phase was 0.1 mL/min. UV detection was adjusted at 298 nm and performed at room temperature. The method has been validated according to the International Conference on Harmonisation guidelines. The method is successfully applied for the determination of TM in bulk powder and pharmaceutical dosage form.

  14. Validation of a stability-indicating RP-LC method for the assessment of recombinant human interleukin-11 and its correlation with bioassay.

    PubMed

    Souto, Ricardo Bizogne; Stamm, Fernanda Pavani; Ribela, Maria Teresa de Carvalho Pinto; Bartolini, Paolo; Calegari, Guilherme Zanini; Dalmora, Sérgio Luiz

    2012-01-01

    A stability-indicating reversed-phase liquid chromatography (RP-LC) method was validated for the assessment of recombinant human interleukin-11 (rhIL-11), based on the ICH guidelines. The method was carried out on a Jupiter C(4) column (250 mm × 4.6 mm i.d.), maintained at 25°C. The mobile phase A consisted of 0.1% trifluoroacetic acid (TFA) and the mobile phase B was acetonitrile with 0.1% TFA, run at a flow rate of 1 mL/min, and using a photodiode array (PDA) detection at 214 nm. Separation was obtained with a retention time of 27.6 min, and was linear over the concentration range of 1-200 µg/mL (r(2) = 0.9995). Specificity was established in degradation studies, which also showed that there was no interference of the excipients. The accuracy was 100.22% with bias lower than 1.25%. Moreover, the in vitro cytotoxicity test of the degraded products showed non-significant differences (p > 0.05). The method was applied to the assessment of rhIL-11 and related proteins in biopharmaceutical dosage forms, and the results were correlated to those of a bioassay.

  15. Stability-indicating liquid chromatographic method for determination of saxagliptin and structure elucidation of the major degradation products using LC-MS.

    PubMed

    Abdel-Ghany, Maha F; Abdel-Aziz, Omar; Ayad, Miriam F; Tadros, Mariam M

    2015-04-01

    A new, simple, selective, reproducible and sensitive stability-indicating liquid chromatographic method was developed and subsequently validated for the determination of saxagliptin (SXG). SXG was subjected to oxidation, thermal, acid hydrolysis, alkali hydrolysis and photodegradation according to ICH guidelines. The major degradation products were separated from the pure drug and the proposed structures' elucidation was performed, using an LC-MS technique. Isocratic chromatographic elution was achieved on a Symmetry(®) C18 column (150 × 4.6 mm, 5 µm), using a mobile phase of potassium dihydrogen phosphate buffer (pH 4.6)-acetonitrile-methanol (40 : 30 : 30, v/v/v) at a flow rate of 1 mL min(-1) with UV detection at 208 nm. Linearity, accuracy and precision were found to be acceptable over the concentration range of 25-400 µg mL(-1). All the results were statistically compared with the reference method, using one-way analysis of variance. The developed method was validated and proved to be specific and accurate for quality control of SXG in pharmaceutical dosage form.

  16. Development and validation of a stability-indicating LC method for the determination of venlafaxine in extended-release capsules and dissolution kinetic studies.

    PubMed

    Bernardi, Larissa S; Oliveira, Paulo R; Murakami, Fábio S; Borgmann, Silvia H M; Arend, Marcela Z; Cardoso, Simone G

    2009-10-01

    A stability-indicating reversed-phase high-performance liquid chromatography method is developed and validated for the determination of venlafaxine hydrochloride (VEN) in extended-release capsules containing spherical beads and for dissolution studies. The method is carried out on a Luna C(18) column (250 mm x 4.6 mm) maintained at 35 degrees C. The mobile phase is composed of ammonium-acetate buffer 32 mM, adjusted to pH 6.8 with phosphoric acid-acetonitrile-methanol (62:30:8, v/v/v), run at a flow rate of 1.0 mL/min, and detection at 226 nm. Validation parameters such as the specificity, linearity, precision, accuracy, and robustness are evaluated, giving results within the acceptable range. In order to evaluate the best dissolution condition, the dissolution profiles are performed under different conditions, such as media (HCl, water, phosphate buffer), apparatus (I and II), and dissolution rates (50, 75, and 100 rpm). The kinetics release mechanism is evaluated by fitting different models, such as the zero order rate, first order, and Higuchi. Moreover, the proposed method is successfully applied for the assay of VEN in extended-release capsules.

  17. Pathogens and fecal indicators in waste stabilization pond systems with direct reuse for irrigation: Fate and transport in water, soil and crops.

    PubMed

    Verbyla, M E; Iriarte, M M; Mercado Guzmán, A; Coronado, O; Almanza, M; Mihelcic, J R

    2016-05-01

    Wastewater use for irrigation is expanding globally, and information about the fate and transport of pathogens in wastewater systems is needed to complete microbial risk assessments and develop policies to protect public health. The lack of maintenance for wastewater treatment facilities in low-income areas and developing countries results in sludge accumulation and compromised performance over time, creating uncertainty about the contamination of soil and crops. The fate and transport of pathogens and fecal indicators was evaluated in waste stabilization ponds with direct reuse for irrigation, using two systems in Bolivia as case studies. Results were compared with models from the literature that have been recommended for design. The removal of Escherichia coli in both systems was adequately predicted by a previously-published dispersed flow model, despite more than 10years of sludge accumulation. However, a design equation for helminth egg removal overestimated the observed removal, suggesting that this equation may not be appropriate for systems with accumulated sludge. To assess the contamination of soil and crops, ratios were calculated of the pathogen and fecal indicator concentrations in soil or on crops to their respective concentrations in irrigation water (termed soil-water and crop-water ratios). Ratios were similar within each group of microorganisms but differed between microorganism groups, and were generally below 0.1mLg(-1) for coliphage, between 1 and 100mLg(-1) for Giardia and Cryptosporidium, and between 100 and 1000mLg(-1) for helminth eggs. This information can be used for microbial risk assessments to develop safe water reuse policies in support of the United Nations' 2030 Sustainable Development Agenda.

  18. Validated Stability-Indicating HPLC-DAD Method for the Simultaneous Determination of Diclofenac Sodium and Diflunisal in Their Combined Dosage Form

    PubMed Central

    Shaalan, Rasha A.; Belal, Tarek S.

    2013-01-01

    A simple, rapid, and highly selective HPLC-DAD method was developed for the simultaneous determination of diclofenac sodium (DIC) and diflunisal (DIF) in pure form and in their combined formulation. Effective chromatographic separation was achieved using a Zorbax SB-C8 (4.6×250 mm, 5 μm particle size) column with a mobile phase composed of 0.05 M phosphoric acid, acetonitrile, and methanol in the ratio of 40:48:12 (by volume). The mobile phase was pumped isocratically at a flow rate of 1 mL/min, and quantification of the analytes was based on measuring their peak areas at 228 nm. The retention times for diflunisal and diclofenac were about 7.9 and 9.5 min, respectively. The reliability and analytical performance of the proposed HPLC procedure were statistically validated with respect to system suitability, linearity, ranges, precision, accuracy, specificity, robustness, detection, and quantification limits. Calibration curves were linear in the ranges of 5–100 μg/mL for both drugs with correlation coefficients >0.9998. The proposed method proved to be selective and stability-indicating by the resolution of the two analytes from four of their related substances and potential impurities as well as from forced-degradation (hydrolysis, oxidation, photolysis, and dry heat) products. The validated HPLC method was successfully applied to the analysis of DIC and DIF in their combined dosage form (suppositories). The proposed method made use of the diode array detector (DAD) as a tool for peak identity and purity confirmation. PMID:24106669

  19. HPLC, TLC, and first-derivative spectrophotometry stability-indicating methods for the determination of tropisetron in the presence of its acid degradates.

    PubMed

    Abdel-Fattah, Laila S; El-Sherif, Zeinab A; Kilani, Khadiga M; El-Haddad, Dalia A

    2010-01-01

    Three stability-indicating assay methods were developed for the determination of tropisetron in a pharmaceutical dosage form in the presence of its degradation products. The proposed techniques are HPLC, TLC, and first-derivative spectrophotometry (1D). Acid degradation was carried out, and the degradation products were separated by TLC and identified by IR, NMR, and MS techniques. The HPLC method was based on determination of tropisetron in the presence of its acid-induced degradation product on an RP Nucleosil C18 column using methanol-water-acetonitrile-trimethylamine (65 + 20 + 15 + 0.2, v/v/v/v) mobile phase and UV detection at 285 nm. The TLC method was based on the separation of tropisetron and its acid-induced degradation products, followed by densitometric measurement of the intact spot at 285 nm. The separation was carried out on silica gel 60 F254 aluminum sheets using methanol-glacial acetic acid (22 + 3, v/v) mobile phase. The 1D method was based on the measurement of first-derivative amplitudes of tropisetron in H2O at the zero-crossing point of its acid-induced degradation product at 271.9 nm. Linearity, accuracy, and precision were found to be acceptable over concentration ranges of 40-240 microg/mL, 1-10 microg/spot, and 6-36 micro/mL for the HPLC, TLC, and 1D methods, respectively. The suggested methods were successfully applied for the determination of the drug in bulk powder, laboratory-prepared mixtures, and a commercial sample.

  20. LC and LC-MS study of stress decomposition behaviour of isoniazid and establishment of validated stability-indicating assay method.

    PubMed

    Bhutani, Hemant; Singh, Saranjit; Vir, Sanjay; Bhutani, K K; Kumar, Raj; Chakraborti, Asit K; Jindal, K C

    2007-03-12

    Isoniazid was subjected to different ICH prescribed stress conditions of thermal stress, hydrolysis, oxidation and photolysis. The drug was stable to dry heat (50 and 60 degrees C). It showed extensive decomposition under hydrolytic conditions, while it was only moderately sensitive to oxidation stress. The solid drug turned intense yellow on exposure to light under accelerated conditions of temperature (40 degrees C) and humidity (75% RH). In total, three major degradation products were detected by LC. For establishment of stability-indicating assay, the reaction solutions in which different degradation products were formed were mixed, and the separation was optimized by varying the LC conditions. An acceptable separation was achieved using a C-18 column and a mobile phase comprising of water:acetonitrile (96:4, v/v), with flow rate and detection wavelength being 0.5 ml min(-1) and 254 nm, respectively. The degradation products appeared at relative retention times (RR(T)) of 0.71, 1.34 and 4.22. The validation studies established a linear response of the drug at concentrations between 50 and 1000 microg ml(-1). The mean values (+/-R.S.D.) of slope, intercept and correlation coefficient were 35,199 (+/-0.88), 114,310 (+/-4.70) and 0.9998 (+/-0.01), respectively. The mean R.S.D. values for intra- and inter-day precision were 0.24 and 0.90, respectively. The recovery of the drug ranged between 99.42 and 100.58%, when it was spiked to a mixture of solutions in which sufficient degradation was observed. The specificity was established through peak purity testing using a photodiode array detector. The method worked well on application to marketed formulation of isoniazid, and a fixed-dose combination containing isoniazid and ethambutol HCl. It was even extendable to LC-MS studies, which were carried out to identify the three degradation products. The m/z values of the peaks at RR(T) 0.71 and RR(T) 1.34 matched with isonicotinic acid and isonicotinamide, respectively

  1. Effect of Chromatographic Conditions on Enantioseparation of Bedaquiline Using Polysaccharide-based Chiral Stationary Phases in RP-HPLC.

    PubMed

    Douša, Michal; Reitmajer, Josef; Lustig, Petr; Štefko, Martin

    2016-04-12

    A sensitive and specific high-performance liquid chromatography method for the separation and determination of bedaquiline stereoisomers has been developed and validated. Ten different chiral columns were tested in a reversed-phase system. Excellent enantioseparation with a resolution of all isomers >2.0 was achieved for all stereoisomers on a Chiralcel OJ-3R column, using a mixture of 10 mM buffer of triethylamine/phosphoric acid pH 7.0 and acetonitrile (40 : 60; v/v). Bedaquiline (BDQ) stereoisomers were detected using UV-vis detector at a wavelength of 227 nm. The influence of mobile phase composition, namely buffer type, mobile phase pH and acetonitrile content in mobile phase, on retention and enantioseparation was studied. Validation of the developed method including linearity, limit of detection, limit of quantification, precision, accuracy and selectivity was performed according to the International Conference on Harmonisation guidelines. The advantages of the method are good enantioseparation and excellent selectivity; therefore, this is suitable for routine determination of chiral purity of (1R,2S)-BDQ in enantiopure active pharmaceutical ingredient.

  2. Simplified RP-HPLC method for multi-residue analysis of abamectin, emamectin benzoate and ivermectin in rice.

    PubMed

    Xie, Xianchuan; Gong, Shu; Wang, Xiaorong; Wu, Yinxing; Zhao, Li

    2011-01-01

    A rapid, reliable and sensitive reverse-phase high-performance liquid chromatography method with fluorescence detection (RP-FLD-HPLC) was developed and validated for simultaneous analysis of the abamectin (ABA), emamectin (EMA) benzoate and ivermectin (IVM) residues in rice. After extraction with acetonitrile/water (2 : 1) with sonication, the avermectin (AVMs) residues were directly derivatised by N-methylimidazole (N-NMIM) and trifluoroacetic anhydride (TFAA) and then analysed on RP-FLD-HPLC. A good linear relationship (r(2 )> 0.99) was obtained for three AVMs ranging from 0.01 to 5 microg ml(-1), i.e. 0.01-5.0 microg g(-1) in rice matrix. The limit of detection (LOD) and the limit of quantification (LOQ) were between 0.001 and 0.002 microg g(-1) and between 0.004 and 0.006 microg g(-1), respectively. Recoveries were from 81.9% to 105.4% and precision less than 12.4%. The proposed method was successfully applied to routine analysis of the AVMs residues in rice.

  3. Development and Validation of RP-HPLC Method for Simultaneous Estimation of Cefpodoxime Proxetil and Dicloxacillin Sodium in Tablets

    PubMed Central

    Acharya, D. R.; Patel, Dipti B.

    2013-01-01

    A simple, accurate, rapid and precise reversed-phase high-performance liquid chromatographic method has been developed and validated for simultaneous determination of cefpodoxime proxetil and dicloxacillin sodium in tablet. The chromatographic separation was carried out on kromasil C18 analytical column (250×4.6 mm; 5 μm) with a mixture of acetonitrile:methanol:trifloroacetic acid (0.001%) with pH 6.5 (30:50:20, v/v/v) as mobile phase; at a flow rate of 1.0 ml/min. UV detection was performed at 235 nm. The dicloxacillin sodium and cefpodoxime proxetil were eluted at 1.92 and 3.35 min, respectively. The peaks were eluted with better resolution. Calibration plots were linear over the concentration range 0.5-20 μg/ml for cefpodoxime proxetil (r2=0.9996) and 5-50 μg/ml for dicloxacillin sodium (r2=0.9987). The method was validated for accuracy, precision, linearity and specificity. The method was very sensitive with limit of detection 0.0726, 0.3685 μg/ml and limit of quantification 0.220, 1.116 μg/ml for cefpodoxime proxetil and dicloxacillin sodium, respectively. The high recovery and low relative standard deviation confirm the suitability of the method for routine determination of cefpodoxime proxetil and dicloxacillin sodium in bulk drug and tablet dosage form. PMID:23901158

  4. Optimization and Validation of RP-HPLC-UV/Vis Method for Determination Phenolic Compounds in Several Personal Care Products

    PubMed Central

    Akkbik, Mohammed; Assim, Zaini Bin; Ahmad, Fasihuddin Badruddin

    2011-01-01

    An HPLC method with ultraviolet-visible spectrophotometry detection has been optimized and validated for the simultaneous determination of phenolic compounds, such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) as antioxidants, and octyl methyl cinnamate (OMC) as UVB-filter in several personal care products. The dynamic range was between 1 to 250 mg/L with relative standard deviation less than 0.25% (n = 4). Limits of detection for BHA, BHT, and OMC were 0.196, 0.170, and 0.478 mg/L, respectively. While limits of quantification for BHA, BHT, and OMC were 0.593, 0.515, and 1.448 mg/L, respectively. The recovery for BHA, BHT, and OMC was ranged from 92.1–105.9%, 83.2–108.9%, and 87.3–103.7%, respectively. The concentration ranges of BHA, BHT, and OMC in 12 commercial personal care samples were 0.13–4.85, 0.16–2.30, and 0.12–65.5 mg/g, respectively. The concentrations of phenolic compounds in these personal care samples were below than maximum allowable concentration in personal care formulation, that is, 0.0004–10 mg/g, 0.002–5 mg/g, and up to 100 mg/g for BHA, BHT, and OMC, respectively. PMID:21760792

  5. Simultaneous quantitative determination of cinnamaldehyde and methyl eugenol from stem bark of Cinnamomum zeylanicum Blume using RP-HPLC.

    PubMed

    Gursale, Atish; Dighe, Vidya; Parekh, Guarang

    2010-01-01

    A simple, sensitive, and precise reversed-phase high performance liquid chromatographic (HPLC) method has been developed, validated and used for simultaneous quantitative determination of cinnamaldehyde and methyl eugenol from the methanolic extract of dried bark powder of Cinnamomum zeylanicum Blume (family Lauraceae). The ultrasonic extraction method was used for the extraction of these compounds. The reversed-phase HPLC analysis was carried out using a Intersil ODS-3V-C(18) (150 mm x 4.6 mm, 5 microm) column and a mobile phase comprising of methanol-acetonitrile-water in the volume ratio of 35:20:45, delivered at a flow rate of 1.0 cm(3)/min. The detection and quantitation of both the compounds was carried out at 221 nm.

  6. Separation and Measurement of Plant Alkaloid Enantiomers by RP-HPLC Analysis of their Fmoc-Alanine Analogs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plants often synthesize secondary metabolites that are enantiomers. Enantiomers can cause very different physiological responses. Ammodendrine (1) and anabasine (2) are teratogens that can cause congenital malformations in livestock and enantiomeric forms of each have been found in Lupinus spp. an...

  7. Identification and RP-HPLC-ESI-MS/MS quantitation of bitter-tasting beta-acid transformation products in beer.

    PubMed

    Haseleu, Gesa; Intelmann, Daniel; Hofmann, Thomas

    2009-08-26

    Thermal treatment of the hop beta-acid colupulone under wort boiling conditions, followed by LC-TOF-MS and 1D/2D NMR spectroscopy, revealed cohulupone, hulupinic acid, nortricyclocolupone, two tricyclocolupone epimers, two dehydrotricyclocolupone epimers, two hydroxytricyclocolupone epimers, and two hydroperoxytricyclocolupone epimers as the major bitter-tasting beta-acid transformation products. Among these compounds, the chemical structures of the hydroxy- as well as the hydroperoxytricyclocolupone epimers have not previously been confirmed by 1D/2D NMR experiments. Depending on their chemical structure, these compounds showed rather low recognition thresholds ranging from 7.9 to 90.3 micromol/L. The lowest thresholds of 7.9 and 14.7 micromol/L were found for cohulupone, imparting a short-lasting, iso-alpha-acid-like bitter impression, and for hydroxytricyclocolupone, exhibiting a long-lasting, lingering, and harsh bitterness perceived on the posterior tongue and throat. Furthermore, HPLC-ESI-MS/MS analysis allowed for the first time a simultaneous detection and quantitation of these bitter-tasting beta-acid transformation products in a range of commercial beer samples without any sample cleanup. Depending on the type of beer, these studies revealed remarkable differences in the concentrations of the individual beta-acid transformation products.

  8. Validation of RP-HPLC Method for Simultaneous Quantification of Bicalutamide and Hesperetin in Polycaprolactone-Bicalutamide-Hesperetin-Chitosan Nanoparticles.

    PubMed

    Arya, Abhishek; Khandelwal, Kiran; Singh, Aanchal; Ahmad, Hafsa; Agrawal, Satish; Khatik, Renuka; Mittapelly, Naresh; Dwivedi, Anil Kumar

    2015-10-01

    Bicalutamide is a non-steroidal anti-androgen drug used for the treatment of androgen-dependent prostate cancer. Hesperetin is a natural bioflavonoid that can be used in combination with bicalutamide to improve efficacy and decrease tolerance. The aim of the present work was to develop and validate a simple, sensitive, rapid reverse phase-high performance liquid chromatographic method for simultaneous estimation of bicalutamide and hesperetin. The validation parameters such as specificity, linearity, precision and accuracy, limit of detection (LOD) and limit of quantification (LOQ) were determined according to International Conference on Harmonization ICH Q2 (R1) guidelines. Chromatographic separation was achieved on Lichrocart(®) CN column (250 × 4 mm, 5 µm, MERCK) with isocratic elution. The retention times and detection wavelength, for hesperetin and bicalutamide were 4.28 min, 288 nm and 5.90 min, 270 nm respectively. The intra-day and inter-day assay precision and accuracy were found to be <2% over linearity of 50-2000 ng/mL with R(2) 0.999. LOD and LOQ, of bicalutamide and hesperetin was 14.70, 44.57 ng/mL and 16.11, 48.84 ng/mL, respectively. The method was successfully applied for encapsulation efficiency and drug release studies from bicalutamide and hesperetin loaded nanoparticles.

  9. Simultaneous determination of gliquidone, fexofenadine, buclizine, and levocetirizine in dosage formulation and human serum by RP-HPLC.

    PubMed

    Arayne, M Saeed; Sultana, Najma; Mirza, Agha Zeeshan; Siddiqui, Farhan Ahmed

    2010-01-01

    In the present paper, a simultaneous method has been developed and validated for estimation of gliquidone in the presence of H(1)-receptor antagonists (fexofenadine hydrochloride, buclizine hydrochloride, and levocetirizine dihydrochloride) using reversed-phase high-performance liquid chromatographic technique. A good chromatographic separation between these drugs was achieved using a mobile phase containing methanol-water (80:20 v/v) at pH 3.5 with a flow rate of 1.0 mL/min; and detection was performed at 230 nm with a UV detector. Validation of the method was performed in terms of linearity, accuracy, precision, and limit of detection and quantification. The linearity of the calibration curves for gliquidone, fexofenadine hydrochloride, buclizine hydrochloride, and levocetirizine dihydrochloride were found to be 0.338-50 microg/mL (r = 0.9964), 5-50 microg/mL (r = 0.9956), 0.325-50 microg/mL (r = 0.9967), and 0.553-50 microg/mL (r = 0.9950), respectively. There was no significant difference between the amount of drug spiked in serum and the amount recovered, and serum did not interfere in simultaneous estimation. Thus, the proposed method is suitable for the simultaneous analysis of active ingredients in tablet dosage forms and human serum.

  10. RP-HPLC analysis of phenolic acids of selected Central European Carex L. (Cyperaceae) species and its implication for taxonomy.

    PubMed

    Bogucka-Kocka, Anna; Szewczyk, Katarzyna; Janyszek, Magdalena; Janyszek, Sławomir; Cieśla, Łukasz

    2011-01-01

    Eighteen species belonging to the Carex genus were checked for the presence and the amount of eight phenolic acids (p-hydroxybenzoic, vanillic, caffeic, syringic, protocatechuic, p-coumaric, sinapic, and ferulic) by means of HPLC. Both the free and bonded phenolic acids were analyzed. The majority of the analyzed acids occurred in the studied species in relatively high amounts. The highest concentrations found were caffeic acid and p-coumaric acid, for which the detected levels were negatively correlated. A very interesting feature was the occurrence of sinapic acid, a compound very rarely detected in plant tissues. Its distribution across the analyzed set of species can be hypothetically connected with the humidity of plants' habitats. Several attempted tests of aggregative cluster analysis showed no similarity to the real taxonomical structure of the genus Carex. Thus, the phenolic acids' composition cannot be considered as the major taxonomical feature for the genus Carex.

  11. Analytical Quality by Design Approach in RP-HPLC Method Development for the Assay of Etofenamate in Dosage Forms.

    PubMed

    Peraman, R; Bhadraya, K; Reddy, Y Padmanabha; Reddy, C Surayaprakash; Lokesh, T

    2015-01-01

    By considering the current regulatory requirement for an analytical method development, a reversed phase high performance liquid chromatographic method for routine analysis of etofenamate in dosage form has been optimized using analytical quality by design approach. Unlike routine approach, the present study was initiated with understanding of quality target product profile, analytical target profile and risk assessment for method variables that affect the method response. A liquid chromatography system equipped with a C18 column (250×4.6 mm, 5 μ), a binary pump and photodiode array detector were used in this work. The experiments were conducted based on plan by central composite design, which could save time, reagents and other resources. Sigma Tech software was used to plan and analyses the experimental observations and obtain quadratic process model. The process model was used for predictive solution for retention time. The predicted data from contour diagram for retention time were verified actually and it satisfied with actual experimental data. The optimized method was achieved at 1.2 ml/min flow rate of using mobile phase composition of methanol and 0.2% triethylamine in water at 85:15, % v/v, pH adjusted to 6.5. The method was validated and verified for targeted method performances, robustness and system suitability during method transfer.

  12. Quality by Design Approach for Simultaneous Estimation of Doxycycline Hyclate and Curcumin by RP-HPLC Method

    PubMed Central

    Dhal, C.; Ahmad, F. J.; Chauhan, A.; Jyothi, M.; Singh, R. M.; Saini, P. K.; Mathur, S. C.; Singh, G. N.

    2015-01-01

    A simple, rapid, reliable, robust and optimized reversed phase high performance liquid chromatographic method for simultaneous estimation of doxycycline hyclate and curcumin was successfully developed and validated as per International Conference on Harmonization guidelines. The objective was achieved in terms of well separated peaks within 10 min on a Waters Sunfire C8 column with dimensions of 250×4.6 mm, particle size 5.0 μm using mobile phase consisting of 30 volumes of potassium dihydrogen phosphate buffer (50 mM) adjusted to pH 6.5±0.1 with triethylamine and 70 volumes of methanol at flow rate of 0.85 ml/min. The column effluents were monitored at 400 nm maintained at ambient column temperature (28o). The developed method was found linear over the concentration range of 200-700 μg/ml for doxycycline hyclate and 8-28 μg/ml for curcumin, the detection and quantitation limit was found to be 26.063 and 78.97 μg/ml for doxycycline hyclate; 0.795 and 2.13 μg/ml for curcumin, respectively. The developed method was optimized using Minitab software version 16 to meet the current quality by design requirements. The method validation was done for linearity, range, detection and quantitation limit, accuracy, precision, specificity, system suitability testing, and robustness. PMID:26997700

  13. Analytical Quality by Design Approach in RP-HPLC Method Development for the Assay of Etofenamate in Dosage Forms

    PubMed Central

    Peraman, R.; Bhadraya, K.; Reddy, Y. Padmanabha; Reddy, C. Surayaprakash; Lokesh, T.

    2015-01-01

    By considering the current regulatory requirement for an analytical method development, a reversed phase high performance liquid chromatographic method for routine analysis of etofenamate in dosage form has been optimized using analytical quality by design approach. Unlike routine approach, the present study was initiated with understanding of quality target product profile, analytical target profile and risk assessment for method variables that affect the method response. A liquid chromatography system equipped with a C18 column (250×4.6 mm, 5 μ), a binary pump and photodiode array detector were used in this work. The experiments were conducted based on plan by central composite design, which could save time, reagents and other resources. Sigma Tech software was used to plan and analyses the experimental observations and obtain quadratic process model. The process model was used for predictive solution for retention time. The predicted data from contour diagram for retention time were verified actually and it satisfied with actual experimental data. The optimized method was achieved at 1.2 ml/min flow rate of using mobile phase composition of methanol and 0.2% triethylamine in water at 85:15, % v/v, pH adjusted to 6.5. The method was validated and verified for targeted method performances, robustness and system suitability during method transfer. PMID:26997704

  14. Validated Spectrophotometric and RP-HPLC-DAD Methods for the Determination of Ursodeoxycholic Acid Based on Derivatization with 2-Nitrophenylhydrazine.

    PubMed

    El-Kafrawy, Dina S; Belal, Tarek S; Mahrous, Mohamed S; Abdel-Khalek, Magdi M; Abo-Gharam, Amira H

    2016-12-23

    This work describes the development, validation, and application of two simple, accurate, and reliable methods for thedetermination of ursodeoxycholic acid (UDCA) in bulk powder and in pharmaceutical dosage forms. The carboxylic acid group in UDCA was exploited for the development of these novel methods. Method 1 is the colorimetric determination of the drug based on its reaction with 2-nitrophenylhydrazine hydrochloride in the presence of a water-soluble carbodiimide coupler [1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride] and pyridine to produce an acid hydrazide derivative, which ionizes to yield an intense violet color with maximum absorption at 553 nm. Method 2 uses reversed-phase HPLC with diode-array detection for the determination of UDCA after precolumn derivatization using the same reaction mentioned above. The acid hydrazide reaction product was separated using a Pinnacle DB C8 column (4.6 × 150 mm, 5 μm particle size) and a mobile phase consisting of 0.01 M acetate buffer (pH 3)-methanol-acetonitrile (30 + 30 + 40, v/v/v) isocratically pumped at a flow rate of 1 mL/min. Ibuprofen was used as the internal standard (IS). The peaks of the reaction product and IS were monitored at 400 nm. Different experimental parameters for both methods were carefully optimized. Analytical performance of the developed methods were statistically validated for linearity, range, precision, accuracy, specificity, robustness, LOD, and LOQ. Calibration curves showed good linear relationships for concentration ranges 32-192 and 60-600 μg/mL for methods 1 and 2, respectively. The proposed methods were successfully applied for the assay of UDCA in bulk form, capsules, and oral suspension with good accuracy and precision. Assay results were statistically compared with a reference pharmacopeial HPLC method, and no significant differences were observed between proposed and reference methods.

  15. RP-HPLC analysis of phenolic compounds and flavonoids in beverages and plant extracts using a CoulArray detector.

    PubMed

    Jandera, Pavel; Skeifíková, Veronika; Rehová, Lucie; Hájek, Tomás; Baldriánová, Lucie; Skopová, Gabriela; Kellner, Vladimír; Horna, Ales

    2005-06-01

    Methods were developed for the analysis of natural antioxidants including phenolic compounds and flavonoids in beverages and plant extracts using gradient HPLC with multi-channel electrochemical coulometric detection. Suitability of various reversed-phase columns for this purpose was compared; pH and mobile phase gradients were optimized with respect to the separation selectivity and sensitivity of detection. Because of different target compounds in various sample types, the overlapping resolution maps and the normalized resolution product approaches described earlier were used to select optimum columns and gradients to suit the analysis of the individual sample types. The methods were applied to the analysis of phenolic compounds and flavonoids in beer, wine, tea, and yacon extracts. 32 phenolic compounds were identified and determined, including derivatives of benzoic and cinnamic acids, flavones, and a few related glycosides. Eight-channel CoulArray detection offers high selectivity and sensitivity with limits of detection in the low microg L(-1) range, at least an order of magnitude lower than single-channel coulometric detection using the Coulochem detector. No special sample pretreatment is necessary and, because of the compatibility of the CoulArray detector with gradient elution, phenolic antioxidants of different polarities can be determined in a single run. In addition to the retention times, the ratios of the areas of the pre-dominant and post-dominant peaks to the area of the dominant peak can be used for improved identification of natural antioxidants.

  16. RP-HPLC Determination of Phenylalkanoids and Monoterpenoids in Rhodiola rosea and Identification by LC-ESI-TOF

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An HPLC method permitting the simultaneous determination of fourteen compounds (phenylalkanoids and monoterpenoids) from the roots of Rhodiola rosea was developed. A separation was achieved within 35 minutes by using C-18 column material, a water/acetonitrile mobile phase, both containing 0.05% phos...

  17. Development and validation of a fast RP-HPLC method for the determination of clobetasol propionate in topical nanocapsule suspensions.

    PubMed

    Fontana, M C; Bastos, M O; Beck, R C R

    2010-09-01

    A simple and rapid high-performance liquid chromatographic method is validated for the determination of clobetasol propionate in topical nanocapsule suspensions. The method is carried out on an RP-18 column with a mobile phase composed of methanol-water (80:20 v/v) and UV detection at 241 nm. The method validation yields good results with respect to linearity, specificity, precision, accuracy, and robustness. The calibration curve in the range of 5.0-40.0 microg/mL shows a correlation coefficient of 0.9999. Precision (intra-day and inter-day) is demonstrated by a relative standard deviation lower than 1.5%. Accuracy is assessed by the recovery test of clobetasol propionate from sample matrixes (98.33 +/- 0.88%). In conclusion, the method is suitable to be applied to assay clobetasol propionate in topical formulations of polymeric nanocapsules, avoiding the use of a buffer solution in the mobile phase.

  18. A Validated RP-HPLC Method for the Analysis of 1-Fluoronaphthalene and Its Process-Related Impurities.

    PubMed

    Karagiannidou, Evrykleia G; Bekiari, Eleni T; Vastardi, Elli I

    2015-09-01

    A simple and precise reversed-phase high-performance liquid chromatography method was developed and validated for the determination of 1-fluoronaphthalene and its process-related impurities, 1-aminonaphthalene, 1-nitronaphthalene, naphthalene and 2-fluoronaphthalene. 1-Fluoronaphthalene is the key starting material for the synthesis of duloxetine hydrochloride active pharmaceutical ingredient and is therefore a potential impurity of the API. The determination of the impurity profile is critical for the safety assessment of a substance and manufacturing process thereof. In duloxetine hydrochloride active pharmaceutical ingredient, only 1-fluoronaphthalene is detected and neither of its related impurities of 1-aminonaphthalene, 1-nitronaphthalene, naphthalene and 2-fluoronaphthalene. Chromatography was carried out on a Symmetry C18 (250 × 4.6 mm, 5 μm) column, using mobile phase A-a mixture of 0.01 Μ KH2PO4 buffer (pH 2.5 ± 0.1):methanol:acetonitrile in the ratio of 35:52:13 v/v/v and mobile phase B-a mixture of methanol:acetonitrile in the ratio of 80:20 v/v at a flow rate of 1.0 mL/min. The analytes were monitored using photo diode array detector at 230 nm. The proposed method is found to be having linearity in the concentration of 0.075-5.000 μg/mL, 0.150-5.000 μg/mL, 0.3125-5.000 μg/mL and 0.3125-5.000 μg/mL for 1-aminonaphthalene, 1-nitronaphthalene, naphthalene and 2-fluoronaphthalene, respectively, with correlation coefficients of 0.9998, 0.9998, 0.9997 and 0.9997, respectively. The proposed method was validated as per the International Conference on Harmonization guidelines. The mean recoveries for all the studied impurities are in the range of 90-110%. Due to its specificity, high precision and accuracy, the developed method can be used for the determination of 1-fluoronaphthalene, key starting material for the synthesis of duloxetine hydrochloride API.

  19. Determination of rifaximin in rat serum by ionic liquid based dispersive liquid-liquid microextraction combined with RP-HPLC.

    PubMed

    Rao, Ramisetti Nageswara; Vali, Rajavarapu Mastan; Rao, Alamanda Vara Prasada

    2012-08-01

    An efficient and environmental friendly ionic liquid based dispersive liquid-liquid microextraction procedure was optimized for determination of rifaximin in rat serum by reverse phase high-performance liquid chromatography. The effect of ionic liquids, dispersive solvents, extractant/disperser ratio, and salt concentrations on sample recovery and enrichment factors were studied. Among the five ionic liquids studied in the present investigation, 1-butyl-3-methylimidazolium hexafluorophosphate was found to be most effective for extraction of rifaximin. The recovery was found to be more than 98% using 1-butyl-3-methylimidazolium hexafluorophosphate and methanol as extraction and dispersive solvents, at an extractant/disperser ratio of 0.43. The recovery was further enhanced to 99.5% by the addition of 5.0% NaCl solution. A threefold enhancement in detection limit was achieved when compared to protein precipitation. The ionic liquid containing the extracted rifaximin was directly injected into HPLC system. The linear relationship was observed in the range of 0.03-10.0 μg/mL with the correlation coefficient (r(2)) 0.9998. Limits of detection and quantification were found to be 0.01 and 0.03 μg/mL, respectively. The relative standard deviation was 2.5%. The method was validated and applied to study pharmacokinetics of rifaxmin in rat serum.

  20. Comparison of RP-HPLC modes to analyse the N-glycome of the free-living nematode Pristionchus pacificus

    PubMed Central

    Yan, Shi; Wilson, Iain B. H.; Paschinger, Katharina

    2015-01-01

    Pristionchus pacificus is a free-living nematode increasingly used as an organism for comparison to the more familiar model Caenorhabditis elegans. In this study, we examined the N-glycans of this organism isolated after serial release with peptide:N-glycosidases F and A; after fluorescent labelling with 2-aminopyridine, chromatographic fractionation by three types of reversed-phase HPLC (with either classical C18, fused core C18 or alkylamide bonded phases) followed by mass spectrometric analyses revealed key features of its N-glycome. In addition to paucimannosidic and oligomannosidic glycans typical of invertebrates, N-glycans with two core fucose residues were detected. Furthermore, a range of glycans carrying up to three phosphorylcholine residues was observed whereas, unlike C. elegans, no tetrafucosylated N-glycans were detected. Structures with three fucose residues, unusual methylation of core α1,3-fucose or with galactosylated fucose motifs were found in low amounts; these features may correlate with a different ensemble or expression of glycosyltransferase genes as compared to C. elegans. From an analytical perspective, both the alkylamide RP-amide and fused core C18 columns, as compared to a classical C18 material, offer advantages in terms of resolution and of elution properties, as some minor pyridylamino-labelled glycans (e.g., those carrying phosphorylcholine) appear in earlier fractions and so potential losses of such structures due to insufficient gradient length can be avoided. PMID:25639343

  1. Preparation of uniform-sized exenatide-loaded PLGA microspheres as long-effective release system with high encapsulation efficiency and bio-stability.

    PubMed

    Qi, Feng; Wu, Jie; Fan, Qingze; He, Fan; Tian, Guifang; Yang, Tingyuan; Ma, Guanghui; Su, Zhiguo

    2013-12-01

    Exenatide-loaded poly(d,l-lactic-co-glycolic acid) (PLGA) microspheres hold great potential as a drug delivery system to treat type 2 diabetes mellitus (T2DM) because they can overcome the shortcoming of exenatide's short half-life and realize sustained efficacy. However, conventional preparation methods often lead to microspheres with a broad size distribution, which in turn would cause poor preparation repeatability, drug efficacy and so forth. In this study, we used Shirasu Porous Glass (SPG) premix membrane emulsification technique characterized with high trans-membrane flux and size controllability to prepare uniform-sized PLGA microspheres. By optimizing trans-membrane pressure and PVA concentration in external aqueous phase, uniform-sized PLGA microspheres with large size (around 20μm) were successfully obtained. To achieve high encapsulation efficiency (EE) and improve in vitro release behavior, we have carefully examined the process parameters. Our results show that using ultrasonication to form primary emulsion, microspheres with high EE were easily obtained, but the rate of in vitro release was very slow. Instead, high EE and appropriate in vitro release were achieved when homogenization with optimized time and speed were employed. Besides, we also systematically investigated the effect of formulations on loading efficiency (LE) as well as the relationship between the resultant size of the microspheres and pore size of the membrane. Finally, through RP-HPLC and CD spectra analysis, we have demonstrated that the bio-stability of exenatide in microspheres was preserved during the preparation process.

  2. Development and validation of a stability-indicating HPLC-UV method for the determination of Thiocolchicoside and its degradation products.

    PubMed

    Aprile, Silvio; Canavesi, Rossana; Bianchi, Michele; Grosa, Giorgio; Del Grosso, Erika

    2017-01-05

    A stability indicating high performance liquid chromatography method has been developed for the determination of thiocolchicoside (TCC) and its main degradation products thiocolchicoside S-oxide (D1SO) and 3-O-demethylthiocolchicine (D3) in liquid and solid formulations. The method was developed based on a previous forced degradation study showing that TCC underwent chemical degradation by acid/base catalyzed hydrolysis and oxidation being the main degradation products D3 and D1SO respectively. The analytes separation and quantification were achieved on a Synergi™ 4μm Polar-RP 80Å, column 150×4.6mm (Phenomenex) using the mobile phase constituted (flow rate 1mLmin(-1)) of eluant A: 20mM sodium acetate buffer (pH 5.0) and eluant B: MeOH:CH3CN (20:80); the elution was performed in gradient mode detecting the analytes at 254nm. The method showed linearity for TCC assay in the 5-15μgmL(-1), range and for unknown (TCCfu) and known (D1SO and D3) degradation products assay, in the 0.5-10μgmL(-1) range: all the square of the correlation coefficients were greater than 0.999. The precision, determined in terms of intra-day and inter-day were expressed as RSDs and resulted to be 1.19, 1.10, 1.37 and 1.04% and 0.95, 0.83, 1.30 and 0.72 for TCC, TCCfu, D1SO and D3, respectively. The method demonstrated also to be accurate; indeed, the average recoveries were 102.1/102.0% for TCC (ampoules and hard capsules respectively), 101.3/100.3% for TCCfu, 101.7/100.2% for D1SO, and 101.4/101.4% for D3. The robustness was also evaluated by variations of mobile phase composition and pH. Finally, the applicability of the method was evaluated by analysis of commercial liquid and solid dosage forms.

  3. Longitudinal Stability of Social Competence Indicators in a Portuguese Sample: Q-Sort Profiles of Social Competence, Measures of Social Engagement, and Peer Sociometric Acceptance

    ERIC Educational Resources Information Center

    Santos, António J.; Vaughn, Brian E.; Peceguina, Inês; Daniel, João R.

    2014-01-01

    This study examines the temporal stability (over 3 years) of individual differences in 3 domains relevant to preschool children's social competence: social engagement/motivation, profiles of behavior and personality attributes characteristic of socially competent young children, and peer acceptance. Each domain was measured with multiple…

  4. Monosomy 1p36 breakpoints indicate repetitive DNA sequence elements may be involved in generating and/or stabilizing some terminal deletions.

    PubMed

    Ballif, Blake C; Gajecka, Marzena; Shaffer, Lisa G

    2004-01-01

    Monosomy 1p36 is the most commonly observed terminal deletion syndrome in humans. Our previous molecular studies on a large cohort of subjects suggest that monosomy 1p36 can result from a variety of chromosomal rearrangements including terminal truncations, interstitial deletions, derivative chromosomes, inverted duplications, and complex rearrangements. However, the mechanism(s) by which rearrangements of 1p36 are generated and/or stabilized is not understood. Sequence analysis of breakpoint junctions may provide valuable clues to the underlying mechanisms of many chromosomal aberrations. In this report, we analyze the breakpoints at the DNA-sequence level in four subjects with variable-sized deletions of 1p36. All four breakpoints fall within repetitive DNA-sequence elements (LINEs, SINEs, etc). This suggests that repetitive DNA-sequence elements may play an important role in generating and/or stabilizing terminal deletions of 1p36. Mechanisms by which repetitive elements may be involved in the process of terminal deletion formation and stabilization are discussed.

  5. Development and validation of a stability-indicating size-indicating size-exclusion LC method for the determination of rhIFN-alpha2a in pharmaceutical formulations.

    PubMed

    Zimmermann, Estevan Sonego; da Silva, Lucélia Magalhães; Calegari, Guilherme Zanini; Stamm, Fernanda Pavani; Souto, Ricardo Bizogne; Dalmora, Sérgio Luiz

    2013-01-01

    A size-exclusion LC method was validated for the determination of interferon-a2a (rhlFN-alpha2a) in pharmaceutical formulations without interference from human serum albumin. Chromatographic separation was performed on a BioSep-SEC-S 2000 column (300 x 7.8 mm id). The mobile phase consisted of 0.001 M monobasic potassium phosphate, 0.008 M sodium phosphate dibasic; 0.2 M sodium chloride buffer, pH 7.4, run at a gradient flow rate and using photodiode array detection at 214 nm, was used. Chromatographic separation was achieved with a retention time of 17.2 min, and the analysis was linear over the concentration range of 1.98 to 198 microg/mL (r2 = 0.9996). The accuracy was 101.39%, with bias lower than 1.67%. The LOD and LOQ were 0.87 and 1.98 microg/mL, respectively. Moreover, method validation demonstrated acceptable results for precision and robustness. The method was applied to the assessment of rhlFN-alpha2a and related proteins in biopharmaceutical dosage forms, and the content/potencies were correlated to those given by a validated RP-LC method and an in vitro bioassay. It was concluded that use of the methods in conjunction allows a great improvement in monitoring stability and QC, thereby ensuring the therapeutic efficacy of the biotechnology-derived medicine.

  6. A Novel Approach to the Surgical Treatment of Lumbar Disc Herniations: Indications of Simple Discectomy and Posterior Transpedicular Dynamic Stabilization Based on Carragee Classification

    PubMed Central

    Ozer, A. F.; Keskin, F.; Oktenoglu, T.; Suzer, T.; Ataker, Y.; Gomleksiz, C.; Sasani, M.

    2013-01-01

    Surgery of lumbar disc herniation is still a problem since Mixter and Barr. Main trouble is dissatisfaction after the operation. Today there is a debate on surgical or conservative treatment despite spending great effort to provide patients with satisfaction. The main problem is segmental instability, and the minimally invasive approach via microscope or endoscope is not necessarily appropriate solution for all cases. Microsurgery or endoscopy would be appropriate for the treatment of Carragee type I and type III herniations. On the other hand in Carragee type II and type IV herniations that are prone to develop recurrent disc herniation and segmental instability, the minimal invasive techniques might be insufficient to achieve satisfactory results. The posterior transpedicular dynamic stabilization method might be a good solution to prevent or diminish the recurrent disc herniation and development of segmental instability. In this study we present our experience in the surgical treatment of disc herniations. PMID:23653862

  7. Stability-indicating HPLC method development and structural elucidation of novel degradation products in posaconazole injection by LC-TOF/MS, LC-MS/MS and NMR.

    PubMed

    Yang, Yidi; Zhu, Xi; Zhang, Fei; Li, Wei; Wu, Ying; Ding, Li

    2016-06-05

    Stress testing was carried out under acidic, alkaline, oxidative, thermal and photolytic conditions to evaluate the intrinsic stability of posaconazole injection. A total of four degradation products were detected and the drug was found to be susceptible to oxidative and thermal degradations. Three unknown degradants formed under oxidative stress condition were isolated by preparative HPLC and unambiguously elucidated by LC-TOF/MS, LC-MS/MS, (1)H NMR, (13)C NMR and 2D NMR techniques. Based on the spectrometric and spectroscopic information, these novel degradation products were unequivocally assigned as the N-oxides of posaconazole. Probable mechanisms for the formation of the degradants were proposed. A new and selective HPLC method was developed and validated to separate, detect and quantify all the degradants in posaconazole injection.

  8. Stability-Indicating UPLC Method for Tramadol HCl Impurities in the Tramadol Injection after Dilution by Infusion Fluids (5% Dextrose and 0.9% Sodium Chloride).

    PubMed

    Binnor, Anil K; Mukkanti, Khagga; Suryanarayana, Mulukutla V; Roy, Sunilendu B

    2013-01-01

    A novel, rapid, and sensitive ultra-performance liquid chromatography (UPLC) method has been developed and validated as per ICH guidelines for the determination of tramadol HCl impurities in the tramadol HCl injection after reconstitution by infusion fluids (5% dextrose and 0.9% sodium chloride). The tramadol HCl injection is for the treatment of patients with moderate-to-severe pain. The stability of the reconstituted solution is critical before intravenous injection. The literature search resulted in few published articles on assays of tramadol in infusion fluids by conventional HPLC. No attempts have yet been made to determine the impurities in infusion fluids, as the concentration of tramadol after reconstitution is extremely low (0.4 mg/mL) and that of impurities is even lower. The proposed method is novel as it allows the quantitation of the impurities of tramadol HCl and is based on modern chromatographic techniques like UPLC. The method was developed using the Waters Acquity BEH C18 column with a mobile phase consisting of a gradient mixture of solvent A (trifluroacetic acid buffer) and solvent B (methanol: acetonitrile). The model stability study was designed by diluting the tramadol HCl injection in the 5% dextrose injection and 0.9% sodium chloride injection. Each mixture was kept under storage at room temperature (25 ± 2°C) for testing at initial, 2, 4, 8, 12, 18 & 24 hours. The validation study illustrates that the proposed method is suitable for the determination of tramadol and its impurities. The proposed method makes use of the LC-MS-compatible mobile phase. It can be useful for the determination of tramadol HCl and its impurities in plasma samples and other pharmaceutical dosage forms.

  9. Study of forced degradation behavior of eletriptan hydrobromide by LC and LC-MS and development of stability-indicating method.

    PubMed

    Jocić, Biljana; Zecević, Mira; Zivanović, Ljiljana; Protić, Ana; Jadranin, Milka; Vajs, Vlatka

    2009-11-01

    The objective of the present study was to report the stability profile of novel antimigrain drug Eletriptan hydrobromide based on the information obtained from forced degradation studies. The drug was subjected to acid (0.1-1 mol L(-1) HCl), neutral and base (0.1-1 mol L(-1) NaOH) hydrolysis and to oxidative decomposition (3-15% (v/v) H(2)O(2)). Photolysis and thermo degradation at 75 degrees C were carried out in methanol solution and in solid state with both Eletriptan hydrobromide bulk drug and the tablet formulation. The products formed under different stress conditions were investigated by LC and LC-MS. The experimental conditions for LC were chosen by employing experimental design and multicriteria decision making methodology. These powerful tools enabled the accomplishment of satisfactory resolution with the shortest possible analysis time. Analytes were separated on a C(18) column (XTerra, 150 mm x 3.9 mm, 5 microm) with the mobile phase composed of methanol-water solution of TEA (pH 6.52, 1%, v/v) (30:70, v/v) pumped at 1 mL min(-1) flow rate. The column temperature was set at 50 degrees C and the detection at 225 nm using DAD detector. The LC method was suitably modified for LC-MS analysis which was further used to characterize the arisen degradation products. The possible degradation pathway was outlined based on the results. The drug appeared to be instable towards every stress condition but oxidation. The stability was not jeopardized even under more exaggerated conditions such as increased temperature of the solutions to 75 degrees C, increased strength of acid/alkali solutions and prolonged testing period. Validation of the LC-DAD method was carried out in accordance with ICH guideline. The method met all required criteria and was applied when testing the commercially available tablets.

  10. Development and validation of a stability-indicating high-performance liquid chromatography method for the simultaneous determination of albuterol, budesonide, and ipratropium bromide in compounded nebulizer solutions.

    PubMed

    Blewett, Anthony J; Varma, Deepti; Gilles, Tiffany; Butcher, Rashidi; Jacob, Jaini; Amazan, Jean; Jansen, Susan A

    2011-01-01

    In recent years, there has been a large increase in the use of pharmaceutical compounding to prepare medications that are not commercially available. The treatment of asthma typically includes the use of albuterol (ALB), ipratropium bromide (IPB), and/or budesonide (BUD) nebulizer solutions. There is currently no commercially available nebulizer solution containing all three of these compounds, and patients must rely on often-unregulated compounding. There is a distinct need for methodologies that can be used to analyze compounded formulations to ensure patient safety. We report an HPLC-UV method to separate and quantitate ALB, IPB, and BUD in nebulizer solutions. The method used a gradient elution to achieve separation via an RP C18 column. The method was validated, showed good selectivity, and was linear over several orders of magnitude. The method was applied to the analysis of nebulizer solutions and determination of their storage stability. Significant ALB-dependent degradation occurred within 5 h in solutions formulated with the free base of ALB, while those containing the sulfate salt of ALB produced no degradation. Alkali solutions can cause base-catalyzed hydrolysis of IPB and degradation of BUD. Compounded formulations containing ALB need to include an acid to control pH and prevent degradation.

  11. Stability-indicating validation of acitretin and isoacitretin in human plasma by LC-ESI-MS/MS bioanalytical method and its application to pharmacokinetic analysis.

    PubMed

    Kumar, Ajay; Monif, Tausif; Khuroo, Arshad; Sasmal, Dinakar; Goswami, Dipanjan; Lahkar, Vijay Kumar

    2011-06-01

    LC- ESI- MS/MS simultaneous bioanalytical method was developed to determine acitretin and its metabolite isoacitretin in human plasma using acitretin-d3 used as the internal standard for both analytes. The compounds were extracted using protein precipitation coupled with liquid-liquid extraction with flash freezing technique. Negative mass transitions (m/z) of acitretin, isoacitretin and acitretin-d3 were detected in multiple reactions monitoring (MRM) mode at 325.4 → 266.3, 325.2 → 266.1 and 328.3 → 266.3, respectively, with a turbo ion spray interface. The chromatographic separation was achieved on an Ascentis-RP amide column (4.6 × 150 mm, 5 µm) with mobile phase delivered in isocratic mode. The method was validated over a concentration range of 1.025-753.217 ng/mL for acitretin and 0.394-289.234 ng/mL for isoacitretin with a limit of quantification of 1.025 and 0.394 ng/mL. The intra-day and inter-day precisions were below 8.1% for acitretin and below 13.8% for isoacitretin, while accuracy was within ±7.0 and ±10.6% respectively. For the first time, the best possible conditions for plasma stability of acitretin and isoacitretin are presented and discussed with application to clinical samples.

  12. Development and validation of a selective, sensitive and stability indicating UPLC-MS/MS method for rapid, simultaneous determination of six process related impurities in darunavir drug substance.

    PubMed

    A, Vijaya Bhaskar Reddy; Yusop, Zulkifli; Jaafar, Jafariah; Aris, Azmi B; Majid, Zaiton A; Umar, Khalid; Talib, Juhaizah

    2016-09-05

    In this study a sensitive and selective gradient reverse phase UPLC-MS/MS method was developed for the simultaneous determination of six process related impurities viz., Imp-I, Imp-II, Imp-III, Imp-IV, Imp-V and Imp-VI in darunavir. The chromatographic separation was performed on Acquity UPLC BEH C18 (50 mm×2.1mm, 1.7μm) column using gradient elution of acetonitrile-methanol (80:20, v/v) and 5.0mM ammonium acetate containing 0.01% formic acid at a flow rate of 0.4mL/min. Both negative and positive electrospray ionization (ESI) modes were operated simultaneously using multiple reaction monitoring (MRM) for the quantification of all six impurities in darunavir. The developed method was fully validated following ICH guidelines with respect to specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, precision, robustness and sample solution stability. The method was able to quantitate Imp-I, Imp-IV, Imp-V at 0.3ppm and Imp-II, Imp-III, and Imp-VI at 0.2ppm with respect to 5.0mg/mL of darunavir. The calibration curves showed good linearity over the concentration range of LOQ to 250% for all six impurities. The correlation coefficient obtained was >0.9989 in all the cases. The accuracy of the method lies between 89.90% and 104.60% for all six impurities. Finally, the method has been successfully applied for three formulation batches of darunavir to determine the above mentioned impurities, however no impurity was found beyond the LOQ. This method is a good quality control tool for the trace level quantification of six process related impurities in darunavir during its synthesis.

  13. Evaluation of different preparation methods for a preservative free triamcinolone acetonide preparation for intravitreal administration: a validated stability indicating HPLC-method.

    PubMed

    Korodi, T; Lachmann, B; Kopelent-Frank, H

    2010-12-01

    Intravitreally applied triamcinolone acetonide (TA) is used to treat a variety of macular diseases. Commercially available products of TA are mainly intended for intramuscular application and contain benzyl alcohol (BA) as a bacteriostatic preservative. Since this agent damages ocular tissues, different methods such as filtration techniques and centrifugation are usually used to eliminate BA from commercial products (40 mg/mL TA, 9.9 mg/mL BA). In this study, we evaluated these methods in regard to their ability to eliminate benzyl alcohol and to guarantee standard doses of triamcinolone acetonide. A new formulation without BA (TA 40 mg/mL) was developped according to the following criteria: autoclavability, stability, and suitability for intravitreal use. For QA/QC evaluation a new rapid and simple HPLC procedure (C18 RP column, mobile phase consisting of methanol-water, 48:52, v/v) to quantify the respective compounds was developed and validated according to ICH guidelines. The HPLC method was proven to be selective, linear, precise and accurate. Analysis of preparations based on commercial products undergoing different filtration techniques showed variable results: TA concentrations of 22-80% of the declared amount were found, and BA content was not reduced to safe levels (up to 39% of initial content remained). Centrifugation methods decreased the concentration of the preservative adequately, however agglomerated TA crystals were observed, leading to irreproducible and deviating particle sizes that are potentially harmful with ocular use. The newly developed preservative free formulation (TA 40 mg/mL) delivered uniform doses of TA, revealed no drug loss during forced light exposure and was proven to be stable, sterile and bacterial endotoxin free after autoclaving and after storage for three months,. The new formulation may offer an alternative for the in-house production of intravitreally applicable TA preparations in hospital pharmacies and should enhance

  14. Determination of Cefixime by a Validated Stability-Indicating HPLC Method and Identification of its Related Substances by LC-MS/MS Studies.

    PubMed

    Talebpour, Zahra; Pourabdollahi, Hakimeh; Rafati, Hasan; Abdollahpour, Asem; Bashour, Yusef; Aboul-Enein, Hassan Y

    2013-01-01

    Cefixime is an important cephalosporin antibiotic that easily decomposes and releases different related substances in preparation and storage steps. The objective of the current study was to develop a simple, precise, and accurate isocratic liquid chromatography (LC) method for the determination of cefixime in the presence of its related substances generated from thermal stress in the bulk drug. The chromatographic conditions were comprised of a reversed-phase C18 column (4.6 × 250 mm, 5 μm) with a mobile phase composed of water: acetonitrile (85:15 v/v, with 0.5% formic acid) and ultraviolet detection (UV). Some thermal degradation products were identified using a proposed liquid chromatography-mass spectrometry method. Five peaks (A, B, C, D, and E impurities based on British Pharmacopoeia) were known and a few unknown peaks appeared in the thermal stress solution of cefixime. The linear regression analysis data for the calibration plot of the LC-UV method showed a good linear relationship in the concentration range 0.9-1000.0 μg mL(-1). The recovery of the optimized method was between 94.6 and 98.4% and the inter- and intra-day relative standard deviations were less than 3.3%. The obtained results shown in the LC-UV proposed method can be conveniently used in a quality control laboratory for routine analysis of cefixime for the assay and related substances, as well as for the evaluation of stability samples of bulk drugs.

  15. Use of chemical indicators of beer aging for ex-post checking of storage conditions and prediction of the sensory stability of beer.

    PubMed

    Cejka, Pavel; Culík, Jiří; Horák, Tomáš; Jurková, Marie; Olšovská, Jana

    2013-12-26

    The rate of beer aging is affected by storage conditions including largely time and temperature. Although bottled beer is commonly stored for up to 1 year, sensorial damage of it is quite frequent. Therefore, a method for retrospective determination of temperature of stored beer was developed. The method is based on the determination of selected carbonyl compounds called as "aging indicators", which are formed during beer aging. The aging indicators were determined using GC-MS after precolumn derivatization with O-(2,3,4,5,6-pentaflourobenzyl)hydroxylamine hydrochloride, and their profile was correlated with the development of old flavor evolving under defined conditions (temperature, time) using both a mathematical and statistical apparatus. Three approaches, including calculation from regression graph, multiple linear regression, and neural networks, were employed. The ultimate uncertainty of the method ranged from 3.0 to 11.0 °C depending on the approach used. Furthermore, the assay was extended to include prediction of beer tendency to sensory aging from freshly bottled beer.

  16. The "Golden Shale": An indicator of coastal stability for Marble Point, McMurdo Sound, over the last four million years

    USGS Publications Warehouse

    Claridge, G.G.C.; Campbell, I.B.

    2007-01-01

    A small sedimentary deposit near Gneiss Point on the western side of McMurdo Sound, previously identified as shale, is described. The deposit is phillipsite, a zeolite that is believed to have formed from the deposition and alteration of volcanic ash in a small ice-marginal saline lake. Other previously recorded occurrences of phillipsite in the dry valleys are believed to be several million years old. A similar age for this deposit is suggested for the Gneiss Point deposit. This is consistent with other weathering and landscape features found in the immediate area, including traces of halloysite in soils. The deposit is very close to sea level but could not have formed if the site had been below sea level, indicating that there has been very little uplift following that which caused the sea to retreat from the Wright Fiord.

  17. Protein linear indices of the 'macromolecular pseudograph alpha-carbon atom adjacency matrix' in bioinformatics. Part 1: prediction of protein stability effects of a complete set of alanine substitutions in Arc repressor.

    PubMed

    Marrero-Ponce, Yovani; Medina-Marrero, Ricardo; Castillo-Garit, Juan A; Romero-Zaldivar, Vicente; Torrens, Francisco; Castro, Eduardo A

    2005-04-15

    A novel approach to bio-macromolecular design from a linear algebra point of view is introduced. A protein's total (whole protein) and local (one or more amino acid) linear indices are a new set of bio-macromolecular descriptors of relevance to protein QSAR/QSPR studies. These amino-acid level biochemical descriptors are based on the calculation of linear maps on Rn[f k(xmi):Rn-->Rn] in canonical basis. These bio-macromolecular indices are calculated from the kth power of the macromolecular pseudograph alpha-carbon atom adjacency matrix. Total linear indices are linear functional on Rn. That is, the kth total linear indices are linear maps from Rn to the scalar R[f k(xm):Rn-->R]. Thus, the kth total linear indices are calculated by summing the amino-acid linear indices of all amino acids in the protein molecule. A study of the protein stability effects for a complete set of alanine substitutions in the Arc repressor illustrates this approach. A quantitative model that discriminates near wild-type stability alanine mutants from the reduced-stability ones in a training series was obtained. This model permitted the correct classification of 97.56% (40/41) and 91.67% (11/12) of proteins in the training and test set, respectively. It shows a high Matthews correlation coefficient (MCC=0.952) for the training set and an MCC=0.837 for the external prediction set. Additionally, canonical regression analysis corroborated the statistical quality of the classification model (Rcanc=0.824). This analysis was also used to compute biological stability canonical scores for each Arc alanine mutant. On the other hand, the linear piecewise regression model compared favorably with respect to the linear regression one on predicting the melting temperature (tm) of the Arc alanine mutants. The linear model explains almost 81% of the variance of the experimental tm (R=0.90 and s=4.29) and the LOO press statistics evidenced its predictive ability (q2=0.72 and scv=4.79). Moreover, the

  18. Bioconversion of rice straw and certain agro-industrial wastes to amendments for organic farming systems: 1. Composting, quality, stability and maturity indices.

    PubMed

    Rashad, Ferial M; Saleh, Walid D; Moselhy, Mohamed A

    2010-08-01

    The microbiological and physicochemical parameters were monitored for 12 weeks during composting of five piles (1.5 x 1.0 x 0.80 m(3)) containing mainly rice straw, soybean residue and enriched with rock phosphate. Two treatments were inoculated with buffalo's manure or composite inoculum, two were supplemented with vinasse and inoculated with either the composite inoculum or with both, the last one was served as a control. Four typical phases of composting were observed during the bioprocess: short initial mesophilic phase followed by, thermophilic, cooling and maturation phases. Physicochemical changes confirmed the succession of microbial populations depending on the temperature of each phase in all treatments. Intense microbial activities led to organic matter mineralization and simultaneously narrow C/N ratios. Inoculation of composting mixtures enhanced the biodegradation of recalcitrant substances. The duration of exposure to a temperature above 55 degrees C for at least 16 consecutive days was quite enough to sanitize the produced composts. After 84 days, all composts reached maturity as indicated by various parameters.

  19. Development and Validation of Stability-Indicating Method for Estimation of Chlorthalidone in Bulk and Tablets with the Use of Experimental Design in Forced Degradation Experiments

    PubMed Central

    Sonawane, Sandeep; Jadhav, Sneha; Rahade, Priya; Chhajed, Santosh; Kshirsagar, Sanjay

    2016-01-01

    Chlorthalidone was subjected to various forced degradation conditions. Substantial degradation of chlorthalidone was obtained in acid, alkali, and oxidative conditions. Further full factorial experimental design was applied for acid and alkali forced degradation conditions, in which strength of acid/alkali, temperature, and time of heating were considered as independent variables (factors) and % degradation was considered as dependent variable (response). Factors responsible for acid and alkali degradation were statistically evaluated using Yates analysis and Pareto chart. Furthermore, using surface response curve, optimized 10% degradation was obtained. All chromatographic separation was carried out on Phenomenex HyperClone C 18 column (250 × 4.6 mm, 5 μ), using mobile phase comprising methanol : acetonitrile : phosphate buffer (20 mM) (pH 3.0 adjusted with o-phosphoric acid): 30 : 10 : 60% v/v. The flow rate was kept constant at 1 mL/min and eluent was detected at 241 nm. In calibration curve experiments, linearity was found to be in the range of 2–12 μg/mL. Validation experiments proved good accuracy and precision of the method. Also there was no interference of excipients and degradation products at the retention time of chlorthalidone, indicating specificity of the method. PMID:27123364

  20. Development of a stability-indicating UPLC method for determining olanzapine and its associated degradation products present in active pharmaceutical ingredients and pharmaceutical dosage forms.

    PubMed

    Krishnaiah, Ch; Vishnu Murthy, M; Kumar, Ramesh; Mukkanti, K

    2011-03-25

    A simple, sensitive and reproducible ultra performance liquid chromatography (UPLC) coupled with a photodiode array detector method was developed for the quantitative determination of olanzapine (OLN) in API and pharmaceutical dosage forms. The method is applicable to the quantification of related substances and assays of drug substances. Chromatographic separation was achieved on Acquity UPLC BEH 100-mm, 2.1-mm, and 1.7-μm C-18 columns, and the gradient eluted within a short runtime, i.e., within 10.0 min. The eluted compounds were monitored at 250 nm, the flow rate was 0.3 mL/min, and the column oven temperature was maintained at 27°C. The resolution of OLN and eight (potential, bi-products and degradation) impurities was greater than 2.0 for all pairs of components. The high correlation coefficient (r(2)>0.9991) values indicated clear correlations between the investigated compound concentrations and their peak areas within the test ranges. The repeatability and intermediate precision, expressed by the RSD, were less than 2.4%. The accuracy and validity of the method were further ascertained by performing recovery studies via a spike method. The accuracy of the method expressed as relative error was satisfactory. No interference was observed from concomitant substances normally added to the tablets. The drug was subjected to the International Conference on Harmonization (ICH)-prescribed hydrolytic, oxidative, photolytic and thermal stress conditions. The performance of the method was validated according to the present ICH guidelines for specificity, limit of detection, limit of quantification, linearity, accuracy, precision, ruggedness and robustness.

  1. Planktonic Foram Sr/Ca Indicates Long-Term Stability of Carbonate Saturation State and Seawater Sr/Ca during the Cenozoic

    NASA Astrophysics Data System (ADS)

    Caves, J. K.; Opdyke, B.; Owens, R.

    2012-12-01

    Changes in ocean chemistry are poorly understood over timescales of tens of millions of years; yet, such changes reflect the interplay of fundamental Earth processes, such as the long-term carbon-cycle, evolution, tectonics, and weathering. Simultaneously constraining two ocean chemical parameters could help deconvolve these processes and improve our understanding of the marine response to anthropogenic perturbations to the carbon cycle. We use a multi-proxy and modeling approach, utilizing planktonic foram Sr/Ca, calcite cements, and box-modeling to produce a first-attempt at a Cenozoic carbonate saturation state (Ω) curve and to improve estimates of long-term seawater Sr/Ca variability. Evidence from both culturing studies and glacial-interglacial records indicate that foram Sr/Ca is dominantly sensitive to Ω, suggesting that foram Sr/Ca can be used to reconstruct Ω if seawater Sr/Ca can be constrained. We apply this new proxy to an updated Cenozoic planktonic foram Sr/Ca record, comprising 1680 records from 18 publications. Our foram Sr/Ca record is largely constant during the Cenozoic, with a minimum at the Miocene-Pliocene boundary and a pronounced shift at 38Mya, corresponding to a major planktonic foram overturning event, which we interpret as a species offset. To constrain seawater Sr/Ca, we use both trace element data from calcite cements and a box-model linked to the 87Sr/86Sr record. Both the model and calcite cement data suggest seawater Sr/Ca has remained relatively stable, with slightly higher values during the Paleogene, a minimum during the mid-Miocene, and variability driven by changes in carbonate deposition and mineralogy. Relative to calcite, Ω was low (~4) during much of the Paleogene, but increased during the Oligocene, reaching a maximum during the mid-Miocene. Ω declined to a local minimum at the Miocene-Pliocene boundary, and has since increased to pre-industrial values of 5-6. This record helps explain the lag between the aragonite

  2. Degradation kinetics study of cabozantinib by a novel stability-indicating LC method and identification of its major degradation products by LC/TOF-MS and LC-MS/MS.

    PubMed

    Wu, Chunyong; Xu, Xue; Feng, Chao; Shi, Yuanyuan; Liu, Wenyuan; Zhu, Xiaoyun; Zhang, Junying

    2014-09-01

    The chemical stability of cabozantinib (CBZ) was investigated using a novel stability-indicating LC method. Forced degradation of CBZ was carried out under acidic, basic, thermal, oxidative and photolytic stress conditions. Hydrolysis and oxidation were the primary pathways for this compound and three major unknown degradation products were characterized by LC/TOF-MS and LC-MS/MS. The major oxidative degradation product was isolated by preparative LC and identified by UV, HRMS and NMR techniques to be N-{4-[(N-oxide-6,7-dimethoxyquinolin-4-yl)oxy]phenyl}-N'-(4-fluorophenyl)-cyclopropane-1,1-dicarboxamide. The developed method was validated as per ICH guidelines and then successfully applied to investigate the degradation kinetics of CBZ. Degradation of CBZ followed first-order kinetics under all experimental conditions. A V-shaped pH-rate profile over the pH range 2-10 was observed with maximum stability at pH 6. The effect of temperature on the rate of CBZ degradation was characterized using the Arrhenius equation. The activation energy for hydrolysis was 57.31kJmol(-1) in alkaline solution.

  3. Internet Addiction: Stability and Change

    ERIC Educational Resources Information Center

    Huang, Chiungjung

    2010-01-01

    This longitudinal study examined five indices of stability and change in Internet addiction: structural stability, mean-level stability, differential stability, individual-level stability, and ipsative stability. The study sample was 351 undergraduate students from end of freshman year to end of junior year. Convergent findings revealed stability…

  4. A validated stability-indicating RP-LC method for the simultaneous determination of amlodipine and perindopril in tablet dosage form and their stress degradation behavior under ICH-recommended stress conditions.

    PubMed

    Gumustas, Mehmet; Ozkan, Sibel A

    2013-01-01

    A stability-indicating RP-LC assay method was developed for the simultaneous determination of the cardiovascular drugs amlodipine and perindopril in the presence of degradation products generated from forced decomposition studies. The developed method is applicable for the determination of related substances in bulk drugs and simultaneous assay in a tablet pharmaceutical dosage form. Separation of the drugs and their degradation products was obtained using an RP Waters Spherisorb ODS1 column (250 x 4.6 mm id, 5 pm particle size) with the mobile phase acetonitrile-water (30 + 70, v/v) containing 15 mM phosphoric acid. The pH of the mobile phase was adjusted to 5.0. A flow rate of 1.2 mL/min was used for the separations, with detection at 215 nm. The chromatographic separation was performed at a column temperature of 45 degrees C. Atenolol was chosen as the internal standard. Amlodipine and perindopril were exposed to thermal, photolytic, hydrolytic, and oxidative stress conditions, and the stressed samples were analyzed by the proposed method. Degradation studies showed that both compounds were degraded under these stress conditions. The method was found to be stability-indicating and can be used for the routine analysis of amlodipine and perindopril in the studied combined tablet dosage form.

  5. Stability-indicating capillary zone electrophoresis method for the assessment of recombinant human granulocyte-macrophage colony-stimulating factor and its correlation with reversed-phase liquid chromatography method and bioassay.

    PubMed

    Dalmora, Sergio Luiz; Butzge, Cairo dos Santos; Machado, Francine Trevisan; Walter, Maurício Elesbão; Dalmora, Maria Elisabeth de Ávila; Souto, Ricardo Bizogne

    2012-05-30

    A stability-indicating capillary zone electrophoresis (CZE) method was validated for the analysis of granulocyte-macrophage colony-stimulating factor (rhGM-CSF) using leuprorelin acetate (LA), as internal standard (IS). A fused-silica capillary (75 μm i.d.; effective length, 72 cm) was used at 25 °C; the applied voltage was 12 kV. The background electrolyte solution consisted of 50mM di-sodium hydrogen phosphate solution at pH 8.8. Injections were performed using a pressure mode at 50 mbar for 9s, with detection by photodiode array detector set at 200 nm. Specificity and stability-indicating capability were established in degradation studies, which also showed that there was no interference of the excipients. The method was linear over the concentration range of 2.5-200 μg mL(-1) (r(2)=0.9995) and the limit of detection (LOD) and limit of quantitation (LOQ) were 0.79 μg mL(-1) and 2.5 μg mL(-1), respectively. The accuracy was 99.14% with bias lower than 1.40%. The method was applied to the quantitative analysis of biopharmaceutical formulations, and the results were correlated to those of a validated reversed-phase LC method (RP-LC), and an in vitro bioassay, showing non-significant differences (p>0.05).

  6. Indices To Measure Stability of Rule Application.

    ERIC Educational Resources Information Center

    Tatsuoka, Kikumi K.

    When learning is taking place, students test their hypotheses and evaluate them, and modify their current theories on the basis of new information. This phenomenon is known as "hypothesis testing view" or "theory changes." Many students change their rules to another while they are taking a test. This study introduced a new…

  7. Development of RP UPLC-TOF/MS, stability indicating method for omeprazole and its related substances by applying two level factorial design; and identification and synthesis of non-pharmacopoeial impurities.

    PubMed

    Jadhav, Sushant Bhimrao; Kumar, C Kiran; Bandichhor, Rakeshwar; Bhosale, P N

    2016-01-25

    A new UPLC-TOF/MS compatible, reverse phase-stability indicating method was developed for determination of Omeprazole (OMP) and its related substances in pharmaceutical dosage forms by implementing Design of Experiment (DoE) i.e. two level full factorial Design (2(3)+3 center points=11 experiments) to understand the Critical Method Parameters (CMP) and its relation with Critical Method Attribute (CMA); to ensure robustness of the method. The separation of eleven specified impurities including conversion product of OMP related compound F (13) and G (14) i.e. Impurity-I (1), OMP related compound-I (11) and OMP 4-chloro analog (12) was achieved in a single method on Acquity BEH shield RP18 100 × 2.1 mm, 1.7 μm column, with inlet filter (0.2 μm) using gradient elution and detector wavelength at 305 nm and validated in accordance with ICH guidelines and found to be accurate, precise, reproducible, robust and specific. The drug was found to degrade extensively in heat, humidity and acidic conditions and forms unknown degradation products during stability studies. The same method was used for LC-MS analysis to identify m/z and fragmentation of maximum unknown impurities (Non-Pharmacopoeial) i.e. Impurity-I (1), Impurity-III (3), Impurity-V (5) and Impurity-VIII (9) formed during stability studies. Based on the results, degradation pathway for the drug has been proposed and synthesis of identified impurities i.e. impurities (Impurity-I (1), Impurity-III (3), Impurity-V (5) and Impurity-VIII (9)) are discussed in detail to ensure in-depth understanding of OMP and its related impurities and optimum performance during lifetime of the product.

  8. Complexity in estimation of esomeprazole and its related impurities' stability in various stress conditions in low-dose aspirin and esomeprazole magnesium capsules.

    PubMed

    Reddy, Palavai Sripal; Hotha, Kishore Kumar; Sait, Shakil

    2013-01-01

    A complex, sensitive, and precise high-performance liquid chromatographic method for the profiling of impurities of esomeprazole in low-dose aspirin and esomeprazole capsules has been developed, validated, and used for the determination of impurities in pharmaceutical products. Esomeprazole and its related impurities' development in the presence of aspirin was traditionally difficult due to aspirin's sensitivity to basic conditions and esomeprazole's sensitivity to acidic conditions. When aspirin is under basic, humid, and extreme temperature conditions, it produces salicylic acid and acetic acid moieties. These two byproducts create an acidic environment for the esomeprazole. Due to the volatility and migration phenomenon of the produced acetic acid and salicylic acid from aspirin in the capsule dosage form, esomeprazole's purity, stability, and quantification are affected. The objective of the present research work was to develop a gradient reversed-phase liquid chromatographic method to separate all the degradation products and process-related impurities from the main peak. The impurities were well-separated on a RP8 column (150 mm × 4.6mm, X-terra, RP8, 3.5μm) by the gradient program using a glycine buffer (0.08 M, pH adjusted to 9.0 with 50% NaOH), acetonitrile, and methanol at a flow rate of 1.0 mL min(-1) with detection wavelength at 305 nm and column temperature at 30°C. The developed method was found to be specific, precise, linear, accurate, rugged, and robust. LOQ values for all of the known impurities were below reporting thresholds. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis, and thermal degradation in the presence of aspirin. The developed RP-HPLC method was validated according to the present ICH guidelines for specificity, linearity, accuracy, precision, limit of detection, limit of quantification, ruggedness, and robustness.

  9. Development of a stability-indicating LC method for determination of a synthetic chalcone derivative in a nanoemulsion dosage form and identification of the main photodegradation product by LC-MS.

    PubMed

    Mattos, Cristiane B; Deponti, Vânia B; Barreto, Fabiano; Simões, Cláudia M O; Andrighetti-Frohner, Carla R; Nunes, Ricardo J; Steindel, Mário; Teixeira, Helder F; Koester, Letícia S

    2012-11-01

    This study aimed to develop and validate a stability indicating LC for the determination of 5-(2-benzoylethenyl)-N-benzyl-2 methoxybenzenesulfonamide (SCD - a synthetic chalcone derivative), and evaluate the degradation profile of the compound under different stress conditions recommended by International Conference on Harmonization (ICH). Chromatographic separation was performed on a silica C18 column, methanol-water mobile phase 70:30 (v:v), pH 5.0 adjusted with the addition of trifluoroacetic acid (TFA) at a flow rate of 1.0 mL min(-1); detection by UV absorption at 330 nm. The method was validated for linearity, precision, accuracy, robustness and specificity. The SCD was subjected to forced degradation and peak photodegradation product was well separated from the pure substance, with retention times significantly different, indicating the specificity of the method. Second-order degradation kinetics of SCD was observed under photodegradation and base-induced degradation. In order to identify the product formed under photodegradation, liquid chromatography-tandem mass spectrometry (LC-MS/MS) was performed. These results indicate that the method can be successfully used in order to assay SCD in a nanoemulsion dosage form, and that this formulation has a protective effect over SCD degradation.

  10. UPLC and LC-MS studies on degradation behavior of irinotecan hydrochloride and development of a validated stability-indicating ultra-performance liquid chromatographic method for determination of irinotecan hydrochloride and its impurities in pharmaceutical dosage forms.

    PubMed

    Kumar, Navneet; Sangeetha, Dhanaraj; Reddy, Sunil P

    2012-10-01

    The objective of the current investigation was to study the degradation behavior of irinotecan hydrochloride under different International Conference on Harmonization (ICH) recommended stress conditions using ultra-performance liquid chromatography and liquid chromatography-mass spectrometry and to establish a validated stability-indicating reverse-phase ultra-performance liquid chromatographic method for the quantitative determination of irinotecan hydrochloride and its seven impurities and degradation products in pharmaceutical dosage forms. Irinotecan hydrochloride was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. Irinotecan hydrochloride was found to degrade significantly in oxidative and base hydrolysis and photolytic degradation conditions. The degradation products were well resolved from the main peak and its impurities, thus proving the stability-indicating power of the method. Chromatographic separation was achieved on a Waters Acquity BEH C8 (100 × 2.1 mm) 1.7-µm column with a mobile phase containing a gradient mixture of solvent A (0.02M KH(2)PO(4) buffer, pH 3.4) and solvent B (a mixture of acetonitrile and methanol in the ratio of 62:38 v/v). The mobile phase was delivered at a flow rate of 0.3 mL/min with ultraviolet detection at 220 nm. The run time was 8 min, within which irinotecan and its seven impurities and degradation products were satisfactorily separated. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness. This method was also suitable for the assay determination of irinotecan hydrochloride in pharmaceutical dosage forms.

  11. Community indicators

    PubMed Central

    Flynn, Andrea; Wells, Samantha

    2014-01-01

    Community indicators are used to assess the impact of alcohol on communities. This article reviews the main data sources for community indicators, discusses their strengths and limitations, and discusses indicators used in reference to four main topics relating to alcohol use and problems at the community level: alcohol use, patterns, and problems; alcohol availability; alcohol-related health outcomes/trauma; and alcohol-related crime and enforcement. It also reviews the challenges associated with collecting community indicator data, along with important innovations in the field that have contributed to better knowledge of how to collect and analyze community-level data on the impact of alcohol. PMID:24881322

  12. An eco-friendly stability-indicating spectrofluorimetric method for the determination of two anticancer stereoisomer drugs in their pharmaceutical preparations following micellar enhancement: Application to kinetic degradation studies

    NASA Astrophysics Data System (ADS)

    El-Kimary, Eman I.; El-Yazbi, Amira F.

    2016-06-01

    A new rapid and highly sensitive stability-indicating spectrofluorimetric method was developed for the determination of two stereoisomers anticancer drugs, doxorubicin (DOX) and epirubicin (EPI) in pure form and in pharmaceutical preparations. The fluorescence spectral behavior of DOX and EPI in a sodium dodecyl sulfate (SDS) micellar system was investigated. It was found that the fluorescence intensity of DOX and EPI in an aqueous solution of phosphate buffer pH 4.0 and in the presence of SDS was greatly (about two fold) enhanced and the mechanism of fluorescence enhancement effect of SDS on DOX was also investigated. The fluorescence intensity of DOX or EPI was measured at 553 nm after excitation at 497 nm. The plots of fluorescence intensity versus concentration were rectilinear over a range of 0.03-2 μg/mL for both DOX and EPI with good correlation coefficient (r > 0.999). High sensitivity to DOX and EPI was attained using the proposed method with limits of detection of 10 and 9 ng/mL and limits of quantitation of 29 and 28 ng/mL, for DOX and EPI, respectively. The method was successfully applied for the determination of DOX and EPI in biological fluids and in their commercial pharmaceutical preparations and the results were concordant with those obtained using a previously reported method. The application of the proposed method was extended to stability studies of DOX following different forced degradation conditions (acidic, alkaline, oxidative and photolytic) according to ICH guidelines. Moreover, the kinetics of the alkaline and oxidative degradation of DOX was investigated and the apparent first-order rate constants and half-life times were calculated.

  13. An eco-friendly stability-indicating spectrofluorimetric method for the determination of two anticancer stereoisomer drugs in their pharmaceutical preparations following micellar enhancement: Application to kinetic degradation studies.

    PubMed

    El-Kimary, Eman I; El-Yazbi, Amira F

    2016-06-15

    A new rapid and highly sensitive stability-indicating spectrofluorimetric method was developed for the determination of two stereoisomers anticancer drugs, doxorubicin (DOX) and epirubicin (EPI) in pure form and in pharmaceutical preparations. The fluorescence spectral behavior of DOX and EPI in a sodium dodecyl sulfate (SDS) micellar system was investigated. It was found that the fluorescence intensity of DOX and EPI in an aqueous solution of phosphate buffer pH4.0 and in the presence of SDS was greatly (about two fold) enhanced and the mechanism of fluorescence enhancement effect of SDS on DOX was also investigated. The fluorescence intensity of DOX or EPI was measured at 553nm after excitation at 497nm. The plots of fluorescence intensity versus concentration were rectilinear over a range of 0.03-2μg/mL for both DOX and EPI with good correlation coefficient (r>0.999). High sensitivity to DOX and EPI was attained using the proposed method with limits of detection of 10 and 9ng/mL and limits of quantitation of 29 and 28ng/mL, for DOX and EPI, respectively. The method was successfully applied for the determination of DOX and EPI in biological fluids and in their commercial pharmaceutical preparations and the results were concordant with those obtained using a previously reported method. The application of the proposed method was extended to stability studies of DOX following different forced degradation conditions (acidic, alkaline, oxidative and photolytic) according to ICH guidelines. Moreover, the kinetics of the alkaline and oxidative degradation of DOX was investigated and the apparent first-order rate constants and half-life times were calculated.

  14. Statistical Optimization of Evaporative Light Scattering Detection for Molten Sucrose Octaacetate and Comparison With Ultraviolet Diode Array Detection Validation Parameters Using Tandem HPLC Ultraviolet Diode Array Detection/Evaporative Light Scattering Detection-Specific Stability-Indicating Method.

    PubMed

    Parmar, Rudrangi; Ghanta, Ajay; Haware, Rahul V; Johnson, Paul R; Stagner, William C

    2016-12-01

    A sucrose octaacetate (SOA) gradient HPLC evaporative light scattering detection (ELSD) and low-wavelength UV-diode array detection (UV-DAD)-specific stability-indicating method development and validation comparison is reported. A central composite response surface design and multicriteria optimization was used to maximize molten SOA area-under-the-curve response and signal-to-noise ratio. The ELSD data were also analyzed using multivariate principal component analysis, analysis of variance, and standard least squares effects modeling. The method suitability and validation parameters of both methods were compared. To the authors' knowledge, this is the first report that validates an ELSD method using a molten analyte. SOA exhibited a low molar absorptivity of 439 absorption units/cm/M in water at 210 nm requiring low-wavelength UV-DAD detection. The low-wavelength UV-DAD method provided substantially better intraday and interday precision, intraday and interday goodness-of-fit, detection limit, and quantitation limit than ELSD. ELSD exhibited a 60-fold greater area-under-the-curve response, better resolution, and 58% more theoretical plates. On balance, the UV-DAD method was chosen for SOA chemical kinetic studies. This study illustrates that ELSD may not always be the best alternative to gradient HPLC low-wavelength UV detection.

  15. Development and Validation of a Stability-Indicating Capillary Electrophoresis Method for the Determination of Zolpidem Tartrate in Tablet Dosage Form with Positive Confirmation using 2D- and 3D-DAD Fingerprints

    PubMed Central

    Al Azzam, Khaldun M.; Yit, Lee Kam; Saad, Bahruddin; Shaibah, Hassan

    2014-01-01

    The aim of the current study was to develop a simple, precise, and accurate capillary zone electrophoresis method for the determination of zolpidem tartrate in tablet dosage form. Separation was conducted in normal polarity mode at 25°C, 22 kV, using hydrodynamic injection for 10 s. Separation was achieved using a background electrolyte of 20 mM disodium hydrogen phosphate adjusted with phosphoric acid (85%), pH at 5.50, and detection at 254 nm. Using the above optimized conditions, complete determination took place in less than 3 min using amiloride HCl as the internal standard. The method was linear over the range of 3–1000 μg mL−1 with a correlation coefficient of 0.9999. Forced degradation studies were conducted by introducing a sample of zolpidem tartrate standard and pharmaceutical sample solutions to different forced degradation conditions, being neutral (water), basic (0.1 M NaOH), acidic (0.1 M HCl), oxidative (10% H2O2), temperature (60°C in oven for 3 days), and photolytic (exposure to UV light at 254 nm for 2 h). Degradation products resulting from the stress studies did not interfere with the detection of zolpidem tartrate and the assay can be considered stability-indicating. PMID:24959406

  16. Migration study of optical brighteners from polymer packing materials to jam squeeze and fruit drink by spectrofluorimetry and RP-HPLC methods.

    PubMed

    Gandhimathi, M; Murugavel, K; Ravi, T K

    2014-06-01

    Optical brighteners are commonly used to modify the appearance and to improve polymer properties of packaging. They are not chemically bound to polymers and able to migrate from packaging into the foods. These migrants are potentially harmful to human health. In concern with human safety an approach was made to analyze three optical brighteners such as diphenylbutadiene, Uvitex-OB, benzophenone in commercial fruit juice and jam. The migration level of these optical brighteners from low density poly ethylene packaging into fruit juice and jam was studied. Two optimized and validated analytical techniques such as spectrofluorimetry and high performance liquid chromatography with photo diode array detector used for migration study. Both methods have shown high correlation coefficients (>0.999), over a concentration range of 0.1-3.2 μg/mL, 0.1-1 μg/mL, 0.05-3.2 μg/mL for diphenylbutadiene, Uvitex-OB and benzophenone respectively. The preliminary studies confirm that the low density poly ethylene layer taken for study contained of diphenylbutadiene and the other two were absent. The migration level of diphenylbutadiene was studied at room temperature and different elevated temperature from 30 °C to 60 °C for up to 3 weeks. At room temperature no migration of diphenylbutadiene was observed where as at higher temperature migration could be observed. The maximum quantity of diphenylbutadiene migrated was found to be 0.0462 mg/kg from tetrapak, and 0.0382 mg/kg from jam squeeze after 3 weeks treatment at 60 °C. The migration of diphenylbutadiene was found to be less than allowable concentration during the study period.

  17. Determination of biogenic amines in traditional Chinese fermented foods by reversed-phase high-performance liquid chromatography (RP-HPLC).

    PubMed

    Gong, Xiao; Wang, Xiaoxi; Qi, Ningli; Li, Jihua; Lin, Lijing; Han, Zhiping

    2014-01-01

    A survey of biogenic amine content of traditional Chinese fermented foods (douchi, sufu, fermented sausage, yulu, and shrimp paste) was carried out. Eight major biogenic amines including putrescine, cadaverine, histamine, phenylethylamine, tyramine, spermine, spermidine and tryptamine were separated by reversed-phase HPLC-DAD on Inertsil ODS-SP column after pre-column derivatisation with dansyl chloride. The results showed that spermine (1.65-3.96 mg 100 g(-1)), putrescine (0.20-10.89 mg 100 g(-1)), cadaverine (3.60-12.14 mg 100 g(-1)), and histamine (0.57-20.24 mg 100 g(-1)) were the most represented amines. All amines were detected in yulu, while sufu showed a much higher content of most amines. Shrimp paste showed the lowest level of total biogenic amines. Moreover, the composition and content of eight biogenic amines in the selected samples varied among different food types, origins and batches. Although the average content for each amine is within the range that may elicit direct adverse reactions, consumers should be aware of the potential synergistic effect among different amines and limit their consumption at each meal.

  18. An Improved RP-HPLC (Reversed-Phase, High-Performance Liquid Chromatography) Method for Determining Nitroaromatics and Nitramines in Water

    DTIC Science & Technology

    1988-11-01

    high - performance liquid chromatography on an LC-18 column. The method employs dilution of an aqueous sample 1:1 with methanol, filtration through a 0.5 micro meter Millex-Sr filter, separation on the LC-18 column using a 1:1 water-methanol eluent, and determination by UV-254 nm. A careful comparison was made with an earlier standard protocol, which uses separation on an LC-8 column with a 50:38:12 water-methanol-acetonitrile eluent. overall, the new procedure provides better separation for a wider range of analytes and equivalent recovery for all

  19. Simultaneous determination of the endogenous free α-lipoic acid and dihydrolipoic acid in human plasma and erythrocytes by RP-HPLC coupled with electrochemical detector.

    PubMed

    Khan, Muhammad Imran; Iqbal, Zafar; Khan, Abad

    2015-01-01

    A highly sensitive, precise, and accurate reversed-phase high performance liquid-chromatography/electrochemical detection method for simultaneous determination of the endogenous free α-lipoic acid and dihydrolipoic acid in biological matrices is presented. The two analytes are extracted from samples with acetonitrile-10% m-phosphoric acid solution(aqueous) (50:50 v/v). To determine the total lipoic acid, samples are treated with tris(2-carboxyethyl)phosphine solution in phosphate buffer: pH 2.5 with 85% o-phosphoric acid prior to deproteination. The two analytes are separated on a C18 (150 × 4.6 mm, 5 μm) analytical column using acetonitrile-50 mM phosphate buffer: pH 2.5 with 85% o-phosphoric acid (35:65 v/v) as the isocratic mobile phase pumped at a flow rate of 2.0 ml/min at the column oven temperature of 35 °C. The column eluents are monitored at a potential of 0.9 V. These analytes are efficiently resolved in <7 min.

  20. Simultaneous quantitative determination of six active components in traditional Chinese medicinal preparation Cerebralcare Granule® by RP-HPLC coupled with diode array detection for quality control.

    PubMed

    Wang, Xiang-yang; Ma, Xiao-hui; Li, Wei; Chu, Yang; Guo, Jia-hua; Zhou, Shui-ping; Zhu, Yong-hong

    2014-09-01

    A simple, accurate and reliable method for the simultaneous separation and determination of six active components (protocatechuic acid, chlorogenic acid, caffeic acid, paeoniflorin, ferulic acid and rosmarinic acid) in traditional Chinese medicinal preparation Cerebralcare Granule(®) (CG) was developed using reverse-phase high-performance liquid chromatography coupled with diode array detector detection. The chromatographic separation was performed on a Hypersil GOLD C18 column with aqueous formic acid (0.1%, v/v) and acetonitrile as mobile phase at a flow rate of 0.2 ml/min at 30 °C. Because of the different UV characteristics of these components, change detection wavelength method was used for quantitative analysis. All of the analytes showed good linearity (r > 0.9992). The established method showed good precision and relative standard deviations (%) for intra-day and inter-day variations of 0.15-1.81 and 0.11-1.98%, respectively. The validated method was successfully applied to the simultaneously determination of six active components in CG from different batches.

  1. Standardization of RP-HPLC methods for the detection of the major peanut allergens Ara h 1, Ara h 2 and Ara h 3.

    PubMed

    Singh, Harmit; Cantoria, Mary Jo; Malave, Poonam; Saputra, Denny; Maleki, Soheila

    2016-03-01

    Crude peanut extract (CPE) was analyzed for three major allergens (Ara h 1, h 2, and h 3) using a C12 and a C18 column at two wavelengths (280 and 220nm) and under different solvent conditions. HPLC profiles were compared for retention time, resolution, and peak heights. CPE samples were spiked with pure allergens to identify the peaks corresponding to allergens. The HPLC fractions of corresponding allergens were collected and freeze-dried in order to perform SDS-PAGE and immunoblotting tests. The best method was identified the one with a shorter retention time, better resolution, and greater peak height as compared with the other methods. In general, the peak heights were greater at 220nm than at 280nm. The major disadvantage of the C12 column was the need for two sets of conditions to identify the allergens as compared to the C18 column where all three allergens could be identified in one run.

  2. Development and Validation of a Rapid RP-HPLC-DAD Analysis Method for the Simultaneous Quantitation of Paclitaxel and Lapatinib in a Polymeric Micelle Formulation.

    PubMed

    Saadat, Ebrahim; Ravar, Fatemeh; Dehghankelishadi, Pouya; Dorkoosh, Farid A

    2016-01-01

    A robust and rapid analysis method was developed and validated for the simultaneous assay of paclitaxel (PTX) and lapatinib (LPT) in a polymeric micelle formulation as a novel drug delivery system using high-performance liquid chromatography (HPLC). The assay was performed using the C18 MZ-Analytical Column (5 μm, 150 × 4.6 mm, OSD-3) which was protected with the C18 pre-column (5 μm, 4.0 × 4.6 mm, OSD-3). The mobile phase was composed of acetonitrile and water (70/30; V/V) with a flow rate of 0.5 mL/min and detection wavelength of 227 nm. Accuracy was reported as the relative error and was found to be less than 6.8%. The interday assay was evaluated to be 3.22% and 5.76% RSD for PTX and LPT, respectively. The intraday precision was found to be at its maximum value of 5.83% RSD. The limit of detection for both PTX and LPT was found to be 1 µg/mL by means of the newly developed method. The limit of quantitation for PTX and LPT was found to be 5 µg/mL. The calibration curves for both drugs were linear in the concentration range of 5 to 80 μg/mL. In vitro release for both drugs from the polymeric micelle was evaluated using the newly developed analysis method.

  3. Determination of lead, cadmium and mercury in microwave-digested foodstuffs by RP-HPLC with an on-line enrichment technique.

    PubMed

    Huang, Zhangjie; Yang, Guangyu; Hu, Qiufen; Yin, Jiayuan

    2003-02-01

    A new method for the simultaneous determination of lead, cadmium and mercury ions in microwave-digested foodstuffs by reversed-phase high-performance liquid chromatography combined with on-line enrichment technique has been developed. The foodstuff samples were digested by microwave digestion. The lead, cadmium and mercury ions can be precolumn derivatized with 5,10,15,20-tetrakis(3-aminophenyl)porphine (T3APP) to form color chelates; then, the Hg-T3APP, Cd-T3APP and Pb-T3APP chelates can be enriched and separated on a valve switching HPLC system combined with on-line enrichment technique. The linearity ranges are 0.01-120 microg/l for each metal ion. The detection limits (S/N = 3) of lead, cadmium and mercury are 1.2 ng/l, 0.5 ng/l and 0.8 ng/l, respectively. This method was applied to the determination of lead, cadmium and mercury in foodstuffs with good results.

  4. Simultaneous determination of four heavy metal ions in tobacco and tobacco additive by online enrichment followed by RP-HPLC and microwave digestion.

    PubMed

    Yang, Guangyu; Zhang, Chengming; Wang, Qiufen; Yin, Jiayuan

    2003-04-01

    A new method for the simultaneous determination of tin, lead, cadmium, and mercury in tobacco and tobacco additive by reversed-phase high-performance liquid chromatography combined with microwave digestion and an online enrichment technique is developed. The tin, lead, cadmium, and mercury ions are precolumn derivatized with tetra-(4-dimethylaminophenyl)-porphyrin (T(4)-DMAPP) to form color chelates. The Sn-T(4)-DMAPP, Hg-T(4)-DMAPP, Cd-T(4)-DMAPP, and Pb-T(4)-DMAPP chelates are absorbed onto the front of the enrichment column using a buffer solution of 0.05 mol/L pyrrolidine-acetic acid (pH = 10.0) as the mobile phase. After the concentration is finished (by switching the six-port switching valve) the retained chelates are back-flushed by the mobile phase and move to the analytical column. The chelate separation on the analytical column is satisfactory using gradient elution with methanol (containing 0.05 mol/L pyrrolidine-acetic acid buffer salt, pH = 10.0) and tetrahydrofuran (containing 0.05 mol/L pyrrolidine-acetic acid buffer salt, pH = 10.0). The linearity range is 0.01-120 micro g/L for each metal ion. The detection limits (S/N = 3) of tin, lead, cadmium, and mercury are 0.6, 0.8, 0.5, and 0.6 ng/L, respectively. This method is applied to the determination of tin, lead, cadmium, and mercury in tobacco and it's additive with good results.

  5. Analysis of flurbiprofen, ketoprofen and etodolac enantiomers by pre-column derivatization RP-HPLC and application to drug-protein binding in human plasma.

    PubMed

    Jin, Yin-Xiu; Tang, Yi-Hong; Zeng, Su

    2008-04-14

    A stereoselective reversed-phase high-performance liquid chromatography (HPLC) assay to determine the enantiomers of flurbiprofen, ketoprofen and etodolac in human plasma was developed. Chiral drug enantiomers were extracted from human plasma with liquid-liquid extraction. Then flurbiprofen and ketoprofen enantiomers reacted with the acylation reagent thionyl chloride and pre-column chiral derivatization reagent (S)-(-)-alpha-(1-naphthyl)ethylamine (S-NEA), and etodolac enantiomers reacted with S-NEA using 1-(3-dimethylaminopropyl)-3-ethyl-carbodiimide (EDC) and 1-hydroxybenzotriazole (HOBT) as coupling agents. The derivatized products were separated on an Agilent Zorbax C18 (4.6 mm x 250 mm, 5 microm) column with a mixture of acetonitrile-0.01 mol.L(-1) phosphate buffer (pH 4.5) (70:30, v/v) for flurbiprofen enantiomers, acetonitrile-0.01 mol.L(-1) phosphate buffer (pH 4.5) (60:40, v/v) for ketoprofen enantiomers and methonal-0.01 mol.L(-1) potassium dihydrogen phosphate buffer (pH 4.5) (88:12, v/v) for etodolac enantiomers as mobile phase. The flow of mobile phase was set at 0.8 mL.min(-1) and the detection wavelength of UV detector was set at 250 nm for flurbiprofen and ketoprofen enantiomers and 278 nm for etodolac enantiomers. The assay was linear from 0.5 to 50 microg.mL(-1) for each enantiomer. The inter- and intra-day precision (R.S.D.) was less than 10% and the average extraction recovery was more than 87% for each enantiomer. The limit of quantification for the method was 0.5 microg.mL(-1) (R.S.D.<10%, n=5). The method developed was used to study the drug-protein binding of flurbiprofen, ketoprofen and etodolac enantiomers in human plasma. The results showed that the stereoselective binding of etodolac enantiomer was observed and flurbiprofen and ketoprofen enantiomers were not.

  6. Development and Validation of a RP-HPLC Method for Estimation of Montelukast Sodium in Bulk and in Tablet Dosage Form.

    PubMed

    Singh, R M; Saini, P K; Mathur, S C; Singh, G N; Lal, B

    2010-03-01

    The present work describes a simple, precise and accurate HPLC method for estimation of montelukast sodium in bulk and in tablet dosage form. The separation was achieved by using octadecylsilane column (C18) and acetonitrile:1 mM sodium acetate adjusted to pH 6.3 with acetic acid in proportion of 90:10 v/v as mobile phase, at a flow rate of 1.5 ml/min. Detection was carried out at 285 nm. The retention time of montelukast sodium was found to be 3.4 min. The limit of detection was found 1.31 µg/ml and limit of quantification 3.97 µg/ml. The accuracy and reliability of the proposed method was ascertained by evaluating various validation parameters like linearity (1-100 µg/ml), precision, accuracy and specificity according to ICH guidelines. The proposed method provides an accurate and precise quality control tool for routine analysis of montelukast sodium in bulk and in tablet dosage form.

  7. Standardization of RP-HPLC methods for the detection of the major peanut allergens Ara h 1, Ara h 2 and Ara h 3

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crude peanut extract (CPE) was analyzed for three major allergens (Ara h 1, h 2, and h 3) using a C12 and a C18 column at two wavelengths (280 and 220 nm) and under different solvent conditions. HPLC profiles were compared for retention time, resolution, and peak heights. CPE samples were spiked wit...

  8. Development and validation of an RP-HPLC method for the quantitation of odanacatib in rat and human plasma and its application to a pharmacokinetic study.

    PubMed

    Police, Anitha; Gurav, Sandip; Dhiman, Vinay; Zainuddin, Mohd; Bhamidipati, Ravi Kanth; Rajagopal, Sriram; Mullangi, Ramesh

    2015-11-01

    A simple, specific, sensitive and reproducible high-performance liquid chromatography (HPLC) assay method has been developed and validated for the estimation of odanacatib in rat and human plasma. The bioanalytical procedure involves extraction of odanacatib and itraconazole (internal standard, IS) from a 200 μL plasma aliquot with simple liquid-liquid extraction process. Chromatographic separation was achieved on a Symmetry Shield RP18 using an isocratic mobile phase at a flow rate of 0.7 mL/min. The UV detection wave length was 268 nm. Odanacatib and IS eluted at 5.5 and 8.6 min, respectively with a total run time of 10 min. Method validation was performed as per US Food and Drug Administration guidelines and the results met the acceptance criteria. The calibration curve was linear over a concentration range of 50.9-2037 ng/mL (r(2) = 0.994). The intra- and inter-day precisions were in the range of 2.06-5.11 and 5.84-13.1%, respectively, in rat plasma and 2.38-7.90 and 6.39-10.2%, respectively, in human plasma. The validated HPLC method was successfully applied to a pharmacokinetic study in rats.

  9. Optimization and validation of an ion-pair RP-HPLC-UV method for the determination of total free iodine in rabbit plasma: application to a pharmacokinetic study.

    PubMed

    Cui, Lijun; Wen, Jun; Zhou, Tingting; Wang, Shuowen; Fan, Guorong

    2009-11-01

    An ion-pair reverse-phase high performance liquid chromatographic method with UV-vis detection has been developed for the determination of total free iodine in rabbit plasma after vaginal administration of povidone-iodine (PVP-I). Sample preparation was done by protein precipitation with acetonitrile in 96-well format and aspirin was used as the internal standard. The 100 microL sodium thiosulfate solution (5 g L(-1)) was added to 100 microL plasma sample before protein precipitation, to convert the total free iodine in plasma to iodide (I(-)). Separation was performed on a C(18) column (200 x 4.6 mm i.d., 5 microm). The mobile phase consisting of a mixture of water phase (containing 10 mmol L(-1) 18-crown-6 ether, 5 mmol L(-1) octylamine and 5 mmol L(-1) sodium dihydrogen phosphate, pH adjusted to 6.0 with phosphoric acid) and acetonitrile in the ratio 70:30 (v/v) was delivered isocraticly at a flow rate of 1.0 mL min(-1). The method was sensitive with a lower limit of quantification of 0.005 microg mL(-1), with good linearity (r(2) > 0.9990) over the linear range of 0.005-2 microg mL(-1). All the validation data, such as linearity, accuracy and precision, were within the required limits. The method was successfully applied to study the pharmacokinetic of PVP-I in rabbits after vaginal administration.

  10. Development and validation of a rapid RP-HPLC method for the determination of cetirizine or fexofenadine with pseudoephedrine in binary pharmaceutical dosage forms.

    PubMed

    Karakuş, Sevgi; Küçükgüzel, Ilkay; Küçükgüzel, S Güniz

    2008-01-22

    The objective of the current study was to develop a simple, accurate, precise and rapid reversed-phase HPLC method and subsequent validation using ICH suggested approach for the determination of antihistaminic-decongestant pharmaceutical dosage forms containing binary mixtures of pseudoephedrine hydrochloride (PSE) with fexofenadine hydrochloride (FEX) or cetirizine dihydrochloride (CET). The chromatographic separation of PSE, FEX and CET was achieved on a Zorbax C8 (150 mm x 4.6mm; 5 microm particle size) column using UV detection at 218 and 222 nm. The optimized mobile phase was consisted of TEA solution (0.5%, pH 4.5)-methanol-acetonitrile (50:20:30, v/v/v). The retention times were 1.099, 2.714 and 3.808 min for PSE, FEX and CET, respectively. The proposed method provided linear responses within the concentration ranges 30-240 and 1.25-10 microg ml(-1) with LOD values of 1.75 and 0.10 microg ml(-1) for PSE and CET, respectively. Linearity range for PSE-FEX binary mixtures were 10-80 and 5-40 microg ml(-1) with LOD values of 0.75 and 0.27 microg ml(-1) for PSE and FEX, respectively. Correlation coefficients (r) of the regression equations were greater than 0.999 in all cases. The precision of the method was demonstrated using intra- and inter-day assay R.S.D. values which were less than 1% in all instances. No interference from any components of pharmaceutical dosage forms or degradation products was observed. According to the validation results, the proposed method was found to be specific, accurate, precise and could be applied to the quantitative analysis of these drugs in capsules containing PSE-CET or extended-release tablets containing PSE-FEX binary mixtures.

  11. Development and Validation of a Rapid RP-HPLC-DAD Analysis Method for the Simultaneous Quantitation of Paclitaxel and Lapatinib in a Polymeric Micelle Formulation

    PubMed Central

    Saadat, Ebrahim; Ravar, Fatemeh; Dehghankelishadi, Pouya; Dorkoosh, Farid A.

    2016-01-01

    A robust and rapid analysis method was developed and validated for the simultaneous assay of paclitaxel (PTX) and lapatinib (LPT) in a polymeric micelle formulation as a novel drug delivery system using high-performance liquid chromatography (HPLC). The assay was performed using the C18 MZ-Analytical Column (5 μm, 150 × 4.6 mm, OSD-3) which was protected with the C18 pre-column (5 μm, 4.0 × 4.6 mm, OSD-3). The mobile phase was composed of acetonitrile and water (70/30; V/V) with a flow rate of 0.5 mL/min and detection wavelength of 227 nm. Accuracy was reported as the relative error and was found to be less than 6.8%. The interday assay was evaluated to be 3.22% and 5.76% RSD for PTX and LPT, respectively. The intraday precision was found to be at its maximum value of 5.83% RSD. The limit of detection for both PTX and LPT was found to be 1 µg/mL by means of the newly developed method. The limit of quantitation for PTX and LPT was found to be 5 µg/mL. The calibration curves for both drugs were linear in the concentration range of 5 to 80 μg/mL. In vitro release for both drugs from the polymeric micelle was evaluated using the newly developed analysis method. PMID:27222608

  12. RP-HPLC method using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate incorporated with normalization technique in principal component analysis to differentiate the bovine, porcine and fish gelatins.

    PubMed

    Azilawati, M I; Hashim, D M; Jamilah, B; Amin, I

    2015-04-01

    The amino acid compositions of bovine, porcine and fish gelatin were determined by amino acid analysis using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate as derivatization reagent. Sixteen amino acids were identified with similar spectral chromatograms. Data pre-treatment via centering and transformation of data by normalization were performed to provide data that are more suitable for analysis and easier to be interpreted. Principal component analysis (PCA) transformed the original data matrix into a number of principal components (PCs). Three principal components (PCs) described 96.5% of the total variance, and 2 PCs (91%) explained the highest variances. The PCA model demonstrated the relationships among amino acids in the correlation loadings plot to the group of gelatins in the scores plot. Fish gelatin was correlated to threonine, serine and methionine on the positive side of PC1; bovine gelatin was correlated to the non-polar side chains amino acids that were proline, hydroxyproline, leucine, isoleucine and valine on the negative side of PC1 and porcine gelatin was correlated to the polar side chains amino acids that were aspartate, glutamic acid, lysine and tyrosine on the negative side of PC2. Verification on the database using 12 samples from commercial products gelatin-based had confirmed the grouping patterns and the variables correlations. Therefore, this quantitative method is very useful as a screening method to determine gelatin from various sources.

  13. Development and validation of RP-HPLC method for simultaneous estimation of nimesulide, phenylephrine hydrochloride, chlorpheniramine maleate and caffeine anhydrous in pharmaceutical dosage form.

    PubMed

    Kumar, Ashok; Sharma, Rishbha; Nair, Anroop; Saini, Gautam

    2012-01-01

    In this study, a simple, specific and accurate reverse phase high performance liquid chromatographic method was developed for the simultaneous determination of nimesulide (NS), phenylephrine hydrochloride (PE), chlorpheniramine maleate (CPM) and caffeine anhydrous (CF) in pharmaceutical dosage forms. A reversed phase Hypersil phenyl column (4.6 mm x 25 cm) with mobile phase having pH 5.5 consisting of methanol and buffer (55:45, v/v) was used. The flow rate was 1.0 mL per minute and the effluents were monitored at 214 nm. The retention times of all the drugs were found to be 7.47 min (NS), 3.944 min (PE), 4.55 min (CF) and 17.15 min (CPM), respectively. The linearity for all the drugs was obtained in the range of 300-800 microg/mL (NS), 15-32 microg/mL (PE), 16-32 microg/mL (CPM) and 30-180 microg/mL (CF), respectively. The results of analysis have been well validated according to guidelines of International Conference of Harmonisation of technical requirements for registration of pharmaceuticals for human use. The method was found to be simple, precise, economical, less time consuming and reproducible. Hence, the suggested procedure could be used for the determination of all the four drugs in commercial preparations.

  14. Social indicators.

    PubMed

    Sheldon, E B; Parke, R

    1975-05-16

    The notions of social indicators and social accounting, expressed by analogy with the national economic accounts, generated excitement in the 1960's, and the interest continues to grow if we may judge from governmental activity and the publication of programmatic and research papers. But the concepts which focused much of the early enthusiasm gave exaggerated promise of policy applications and provided an unproductive b