Sample records for floating matrix tablets

  1. Formulation and evaluation of floating matrix tablet of stavudine

    PubMed Central

    Prajapati, Pankaj H; Nakum, Vijay V; Patel, Chhagan N

    2012-01-01

    Background/Aim: The purpose of the study was to prolong the gastric residence time of stavudine by designing its floating tablets and to study the influence of different polymers on its release rate. Materials and Methods: The floating mix matrix tablets of stavudine were prepared by melt granulation method. Beeswax was used as hydrophobic meltable material. Hydroxypropyl methylcellulose (HPMC), sodium bicarbonate, and ethyl cellulose were used as matrixing agent, gas generating agent, and floating enhancer, respectively. The prepared tablets were evaluated for physicochemical parameters such as hardness, weight variation, friability, floating properties (floating lag time, total floating time), drug content, stability study, and in vitro drug release. The drug- polymer interaction was studied by Differential Scanning Calorimetry (DSC) thermal analysis and Fourier transform infared (FT-IR). Results: The floating lag time of all the formulations was within the prescribed limit (<3 min). All the formulations showed good matrix integrity and retarded the release of drug for 12 h except the formulation F5.The concentration of beeswax (X1), HPMC K4M (X2), and ethyl cellulose (X3) were selected as independent variables and drug release values at 1 (Q1), at 6 (Q6) and at 12 h (Q12) as dependent variables. Formulation F7 was selected as an optimum formulation as it showed more similarity in dissolution profile with theoretical profile (similarity factor, f2 = 70.91). The dissolution of batch F7 can be described by zero-order kinetics (R2 =0.9936) with anomalous (non-Fickian) diffusion as the release mechanism (n=0.545). There was no difference observed in release profile after temperature sensitivity study at 40°C/75% relative humidity (RH) for 1 month. Conclusion: It can be concluded from this study that the combined mix matrix system containing hydrophobic and hydrophilic polymer minimized the burst release of drug from the tablet and achieved a drug release by zero-order kinetics, which is practically difficult with only hydrophilic matrix. PMID:23119237

  2. Effect of bioadhesion on initial in vitro buoyancy of effervescent floating matrix tablets of ciprofloxacin HCL

    PubMed Central

    Negi, Jeetendra Singh; Trivedi, Abhinav; Khanduri, Praveen; Negi, Vandana; Kasliwal, Nikhil

    2011-01-01

    The purpose of this study was to investigate effect of bioadhesion on the initial in vitro buoyancy behaviour of effervescent matrix tablets of ciprofloxacin HCl (CIPRO). Tablets were prepared by direct compression using HPMC K4M and Carbopol 971P as hydrophilic-controlled release polymers, sodium bicarbonate (NaHCO3) as gas-generating agent, polyplasdone XL, Explotab and Ac-Di-Sol as swelling agents. Tablets were evaluated for normal and modified initial in vitro floating behavior, floating duration, swelling behavior and in vitro drug release studies. A modified buoyancy lag time for tablets was determined in order to include the effect of bioadhesion on initial buoyancy. The initial buoyancy was found depended on bioadhesion ability of tablets. The lowest modified buoyancy lag time of 20 seconds was obtained for Formulation F7 having both NaHCO3 and polyplasdone XL. The floating duration was also found dependent on concentration of NaHCO3 and swelling agents. The drug release of F7 was also sustained up to 12-hr duration with anomalous drug transport mechanism. PMID:22171304

  3. Lornoxicam gastro retentive floating matrix tablets: Design and in vitro evaluation.

    PubMed

    Sathiyaraj, S; Devi, Ramya D; Hari, Vedha B N

    2011-07-01

    The objective of this present investigation is to prolong the gastric residence time of Lornoxicam by fabricating it into a floating sustained release matrix tablets. Lornoxicam, a potent oxicam group of non-steroidal anti-inflammatory drugs, suffers from relatively short half life of 2 to 3 hrs showing maximal absorption in proximal gastro intestinal tract region necessitating its need to be formulated as a floating sustained release matrix tablets. In this current investigation, hydroxyl propyl methyl cellulose K15M, a high viscous grade polymer with apparent viscosity of 15,000 cps, was kept as a variable (10-50%) and calcium carbonate (13%) was used as a gas generator. The prepared blends were subjected for its pre-formulation characterization. The directly compressed tablets were evaluated for physical parameters such as weight uniformity, hardness, friability, drug content, in-vitro buoyancy with axial and radial enlargement measurement, swelling index. From the investigation it was observed that the buoyancy lasted for up to 24 hrs. Fourier transform infra-red spectroscopy peaks assured the compatibility of the drug with excipients and confirmed the presence of pure drug in the formulation. It was supported by in-vitro dissolution studies; and the dissolution data was subjected to various release kinetic models to understand the mechanism of drug release. PMID:22171312

  4. Floating tablet of trimetazidine dihydrochloride: an approach for extended release with zero-order kinetics.

    PubMed

    Abdelbary, Ahmed; El-Gazayerly, Omaima N; El-Gendy, Nashwa A; Ali, Adel A

    2010-09-01

    Trimetazidine dihydrochloride is an effective anti-anginal agent; however, it is freely soluble in water and suffers from a relatively short half-life. To solve this encumbrance, it is a prospective candidate for fabricating trimetazidine extended-release formulations. Trimetazidine extended-release floating tablets were prepared using different hydrophilic matrix forming polymers including HPMC 4000 cps, carbopol 971P, polycarbophil, and guar gum. The tablets were fabricated by dry coating technique. In vitro evaluation of the prepared tablets was performed by the determination of the hardness, friability, content uniformity, and weight variation. The floating lag time and floating duration were also evaluated. Release profile of the prepared tablets was performed and analyzed. Furthermore, a stability study of the floating tablets was carried out at three different temperatures over 12 weeks. Finally, in vivo bioavailability study was done on human volunteers. All tablet formulas achieved < 0.5 min of floating lag time, more than 12 h of floating duration, and extended t (1/2). The drug release in all formulas followed zero-order kinetics. T4 and T8 tablets contained the least polymer concentration and complied with the dissolution requirements for controlled-release dosage forms. These two formulas were selected for further stability studies. T8 exhibited longer expiration date and was chosen for in vivo studies. T8 floating tablets showed an improvement in the drug bioavailability compared to immediate-release tablets (Vastrel® 20 mg). PMID:20582493

  5. Comparative evaluation of single and bilayered lamotrigine floating tablets

    PubMed Central

    Lakshmi, PK; Sridhar, M; Shruthi, B

    2013-01-01

    Aim: The purpose of this study was to prepare lamotrigine (LM) bilayered and single layered floating tablets and to compare their release profiles. Materials and Methods: LM floating tablets were prepared by direct compression method. Drug, hydroxy propyl methyl cellulose K4M, lactose monohydrate and polyvinylpyrrolidone K30 constitute controlled release layer components and floating layer components includes polymers and sodium bicarbonate. The prepared tablets were evaluated for physicochemical parameters such as hardness, friability, weight variation, thickness, floating lag time (FLT), floating time, in vitro buoyancy study, in vitro release studies. The drug-polymer interaction was studied by fourier transform infrared and differential scanning calorimetry. Results and Discussion: The FLT of all the formulations were within the prescribed limits (<3 min). When ethyl cellulose was used as floating layer component, tablets showed good buoyancy effect but eroded within 6-8 h. Hence it was replaced with hydroxypropyl cellulose -M hydrophilic polymer, which showed good FLT and floating duration for 16 h. Formulation LFC4 was found to be optimized with dissolution profile of zero order kinetics showing fickian diffusion. A comparative study of bilayered and single layered tablets of LM showed a highest similarity factor of 83.03, difference factor of 2.74 and t-test (P < 0.05) indicates that there is no significant difference between them. Conclusion: Though bilayered tablet possess many advantages, single layered tablet would be economical, cost-effective and reproducible for large scale production in the industry. However, the results of present study demonstrated that the in vitro development of bilayered gastro retentive floating tablets with controlled drug release profile for LM is feasible. PMID:24167788

  6. Design and evaluation of gastroretentive levofloxacin floating mini-tablets-in-capsule system for eradication of Helicobacter pylori.

    PubMed

    El-Zahaby, Sally A; Kassem, Abeer A; El-Kamel, Amal H

    2014-12-01

    Gastroretentive levofloxacin (LVF) floating mini-tablets for the eradication of Helicobacter pylori (H. pylori) were prepared using the matrix forming polymer hydroxypropyl methylcellulose (HPMC K100M), alone or with Carbopol 940P in different ratios by wet granulation technique. Buoyancy of mini-tablets was achieved by an addition of an effervescent mixture consisting of sodium bicarbonate and anhydrous citric acid to some formulations. The prepared mini-tablets were evaluated for weight variation, thickness, friability, hardness, drug content, in vitro buoyancy, water uptake and in vitro release. The optimized formula was subjected to further studies: FT-IR, DSC analysis and in vivo examination in healthy volunteers. The prepared mini-tablets exhibited satisfactory physicochemical characteristics. Incorporation of gas-generating agent improved the floating parameters. HPMC K100M mini-tablet formulation (F1) offered the best controlled drug release (>8 h) along with floating lag time <1 s and total floating time >24 h. The obtained DSC thermograms and FT-IR charts indicated that there is no positive evidence for the interaction between LVF and ingredients of the optimized formula. The in vivo test confirmed the success of the optimized formula F1 in being retained in the stomach of the volunteers for more than 4 h. LVF floating mini-tablets based on HPMC K100M is a promising formulation for eradication of H. pylori. PMID:25561871

  7. Design and evaluation of effervescent floating tablets based on hydroxyethyl cellulose and sodium alginate using pentoxifylline as a model drug.

    PubMed

    Rahim, Safwan Abdel; Carter, Paul A; Elkordy, Amal Ali

    2015-01-01

    The aim of this work was to design and evaluate effervescent floating gastro-retentive drug delivery matrix tablets with sustained-release behavior using a binary mixture of hydroxyethyl cellulose and sodium alginate. Pentoxifylline was used as a highly water-soluble, short half-life model drug with a high density. The floating capacity, swelling, and drug release behaviors of drug-loaded matrix tablets were evaluated in 0.1 N HCl (pH 1.2) at 37°C±0.5°C. Release data were analyzed by fitting the power law model of Korsmeyer-Peppas. The effect of different formulation variables was investigated, such as wet granulation, sodium bicarbonate gas-forming agent level, and tablet hardness properties. Statistical analysis was applied by paired sample t-test and one-way analysis of variance depending on the type of data to determine significant effect of different parameters. All prepared tablets through wet granulation showed acceptable physicochemical properties and their drug release profiles followed non-Fickian diffusion. They could float on the surface of dissolution medium and sustain drug release over 24 hours. Tablets prepared with 20% w/w sodium bicarbonate at 50-54 N hardness were promising with respect to their floating lag time, floating duration, swelling ability, and sustained drug release profile. PMID:25848220

  8. Design and evaluation of effervescent floating tablets based on hydroxyethyl cellulose and sodium alginate using pentoxifylline as a model drug

    PubMed Central

    Rahim, Safwan Abdel; Carter, Paul A; Elkordy, Amal Ali

    2015-01-01

    The aim of this work was to design and evaluate effervescent floating gastro-retentive drug delivery matrix tablets with sustained-release behavior using a binary mixture of hydroxyethyl cellulose and sodium alginate. Pentoxifylline was used as a highly water-soluble, short half-life model drug with a high density. The floating capacity, swelling, and drug release behaviors of drug-loaded matrix tablets were evaluated in 0.1 N HCl (pH 1.2) at 37°C±0.5°C. Release data were analyzed by fitting the power law model of Korsmeyer–Peppas. The effect of different formulation variables was investigated, such as wet granulation, sodium bicarbonate gas-forming agent level, and tablet hardness properties. Statistical analysis was applied by paired sample t-test and one-way analysis of variance depending on the type of data to determine significant effect of different parameters. All prepared tablets through wet granulation showed acceptable physicochemical properties and their drug release profiles followed non-Fickian diffusion. They could float on the surface of dissolution medium and sustain drug release over 24 hours. Tablets prepared with 20% w/w sodium bicarbonate at 50–54 N hardness were promising with respect to their floating lag time, floating duration, swelling ability, and sustained drug release profile. PMID:25848220

  9. Formulation and evaluation of floating tablet of H2-receptor antagonist.

    PubMed

    Kesarla, Rajesh S; Vora, Pratik Ashwinbhai; Sridhar, B K; Patel, Gunvant; Omri, Abdelwahab

    2014-09-22

    Abstract Context: Conventional sustained dosage form of ranitidine hydrochloride (HCl) does not prevent frequent administration due to its degradation in colonic media and limited absorption in the upper part of GIT. Objectives: Ranitidine HCl floating tablet was formulated with sublimation method to overcome the stated problem. Methods: Compatibility study for screening potential excipients was carried out using Fourier transform infrared spectroscopy (FT-IR) and differential scanning chromatography (DSC). Selected excipients were further evaluated for optimizing the formulation. Preliminary screening of binder, polymer and sublimating material was based on hardness and drug release, drug release with release kinetics and floating lag time with total floatation time, respectively. Selected excipients were subjected to 3(2) factorial design with polymer and sublimating material as independent factors. Matrix tablets were obtained by using 16/32" flat-faced beveled edges punches followed by sublimation. Results: FT-IR and DSC indicated no significant incompatibility with selected excipients. Klucel-LF, POLYOX WSR N 60?K and l-menthol were selected as binder, polymer and sublimating material, respectively, for factorial design batches after preliminary screening. From the factorial design batches, optimum concentration to release the drug within 12?h was found to be 420?mg of POLYOX and 40?mg of l-menthol. Stability studies indicated the formulation as stable. Conclusion: Ranitidine HCl matrix floating tablets were formulated to release 90% of drug in stomach within 12?h. Hence, release of the drug could be sustained within narrow absorption site. Moreover, the dosage form was found to be floating within a fraction of second independent of the pH of media ensuring a robust formulation. PMID:25243639

  10. [Modern polymers in matrix tablets technology].

    PubMed

    Zimmer, ?ukasz; Kasperek, Regina; Poleszak, Ewa

    2014-01-01

    Matrix tablets are the most popular method of oral drug administration, and polymeric materials have been used broadly in matrix formulations to modify and modulate drug release rate. The main goal of the system is to extend drug release profiles to maintain a constant in vivo plasma drug concentration and a consistent pharmacological effect. Polymeric matrix tablets offer a great potential as oral controlled drug delivery systems. Cellulose derivatives, like hydroxypropyl methylcellulose (HPMC) are often used as matrix formers. However, also other types of polymers can be used for this purpose including: Kollidon SR, acrylic acid polymers such as Eudragits and Carbopols. Nevertheless, polymers of natural origin like: carragens, chitosan and alginates widely used in the food and cosmetics industry are now coming to the fore of pharmaceutical research and are used in matrix tablets technology. Modern polymers allow to obtain matrix tablets by 3D printing, which enables to develop new formulation types. In this paper, the polymers used in matrix tablets technology and examples of their applications were described. PMID:25739125

  11. Development of bilayer floating tablet of amoxicillin and Aloe vera gel powder for treatment of gastric ulcers.

    PubMed

    Ranade, Arati N; Wankhede, Sonali S; Ranpise, Nisharani S; Mundada, Mayur S

    2012-12-01

    Usual treatment for Helicobacter pylori-induced peptic ulcer includes a 'triple therapy' consisting of two antibiotics (amoxicillin and clarithromycin) and a proton pump inhibitor (omeprazole). The objective of this project work was defined with a view to retain the drug in stomach for better antiulcer activity and substituting one of the synthetic drugs in this therapy with a herbal alternative. Hence, aim of the present work was to design and develop a bilayer floating tablet of amoxicillin and Aloe vera gel powder for the treatment of peptic ulcer. A. vera gel powder is used for its cytoprotective action. Bilayer floating tablets were prepared by applying direct compression technique. The proportion of sodium bicarbonate and citric acid was adjusted to get the least possible lag time with good matrix integrity and total floating time. Polymer concentration was adjusted to get the maximum release in 8 h. The formulation was developed using hydroxypropyl methyl cellulose (HPMC) K4M and HPMC K100M in a ratio of 85:15 along with 1:4 ratio of effervescent agents was found to give floating lag time of less than 1 min with total floating time of more than 8 h and 97.0% drug release in 8 h. In vivo study in rats meets the requirement of antiulcer activity for bilayer tablet in comparison to single amoxicillin as standard. PMID:23135966

  12. Design and characterization of controlled release gastro-retentive floating tablet of an atypical psychotropic agent

    PubMed Central

    Ukawala, Ravikumar; Singhvi, Gautam; Jain, Suresh; Shukla, Vipin; Yadav, Nilesh; Sharma, Sohiny

    2012-01-01

    The purpose of the present work was to design and evaluate the once daily sustained release matrix type gastro-retentive floating tablet of Quetiapine Fumarate base on hydrophilic matrices of HPMC, sodium CMC and Carbopol. Sodium bicarbonate was incorporated as a gas-generating agent to give buoyancy. In-vitro drug release studies were performed in pH 1.2 buffer using USP type II paddle at 50 rpm. The release rate of drug decreased with increasing polymer proportion of HPMC K15M from 20 to 60 mg. Formulation with desired drug release achieved with combination of sodium CMC and K15M in ratio of 1:3. The drug release mechanism was predominantly found to be Non-Fickian diffusion and Higuchi controlled. PMID:23066221

  13. Design and characterization of controlled release gastro-retentive floating tablet of an atypical psychotropic agent.

    PubMed

    Ukawala, Ravikumar; Singhvi, Gautam; Jain, Suresh; Shukla, Vipin; Yadav, Nilesh; Sharma, Sohiny

    2012-03-01

    The purpose of the present work was to design and evaluate the once daily sustained release matrix type gastro-retentive floating tablet of Quetiapine Fumarate base on hydrophilic matrices of HPMC, sodium CMC and Carbopol. Sodium bicarbonate was incorporated as a gas-generating agent to give buoyancy. In-vitro drug release studies were performed in pH 1.2 buffer using USP type II paddle at 50 rpm. The release rate of drug decreased with increasing polymer proportion of HPMC K15M from 20 to 60 mg. Formulation with desired drug release achieved with combination of sodium CMC and K15M in ratio of 1:3. The drug release mechanism was predominantly found to be Non-Fickian diffusion and Higuchi controlled. PMID:23066221

  14. Formulation and In Vitro, In Vivo Evaluation of Effervescent Floating Sustained-Release Imatinib Mesylate Tablet

    PubMed Central

    Kadivar, Ali; Kamalidehghan, Behnam; Javar, Hamid Akbari; Davoudi, Ehsan Taghizadeh; Zaharuddin, Nurul Dhania; Sabeti, Bahareh; Chung, Lip Yong; Noordin, Mohamed Ibrahim

    2015-01-01

    Introduction Imatinib mesylate is an antineoplastic agent which has high absorption in the upper part of the gastrointestinal tract (GIT). Conventional imatinib mesylate (Gleevec) tablets produce rapid and relatively high peak blood levels and requires frequent administration to keep the plasma drug level at an effective range. This might cause side effects, reduced effectiveness and poor therapeutic management. Therefore, floating sustained-release Imatinib tablets were developed to allow the tablets to be released in the upper part of the GIT and overcome the inadequacy of conventional tablets. Methodology Floating sustained-release Imatinib mesylate tablets were prepared using the wet granulation method. Tablets were formulated using Hydroxypropyl Methylcellulose (HPMC K4M), with Sodium alginate (SA) and Carbomer 934P (CP) as release-retarding polymers, sodium bicarbonate (NaHCO3) as the effervescent agent and lactose as a filler. Floating behavior, in vitro drug release, and swelling index studies were conducted. Initial and total drug release duration was compared with a commercial tablet (Gleevec) in 0.1 N HCl (pH 1.2) at 37 ± 0.5°C for 24 hours. Tablets were then evaluated for various physical parameters, including weight variation, thickness, hardness, friability, and drug content. Consequently, 6 months of physical stability studies and in vitro gastro-retentive studies were conducted. Results and Discussion Statistical data analysis revealed that tablets containing a composition of 14.67% w/w HPMC K4M, 10.67%, w/w Na alginate, 1.33%, w/w Carbomer 934P and 9.33%, w/w NaHCO3 produced the most favorable formulation to develop 24-hour sustained-release tablets with optimum floating behavior and satisfactory physicochemical characteristics. Furthermore, in vitro release study revealed that the formulated SR tablet had significantly lower Cmax and higher Tmax compared to the conventional tablet (Gleevec). Thus, formulated SR tablets preserved persistent concentration of plasma up to 24 hours. Conclusion In conclusion, in order to suggest a better drug delivery system with constant favorable release, resulting in optimized absorption and less side effects, formulated CP-HPMC-SA based imatinib mesylate floating sustained-release tablets can be a promising candidate for cancer chemotherapy. PMID:26035710

  15. THEOPHYLLINE LOADED GASTRORETENTIVE FLOATING TABLETS BASED ON HYDROPHILIC POLYMERS: PREPARATION AND IN VITRO EVALUATION

    Microsoft Academic Search

    FERDOUS KHAN; MILLAT IBN RAZZAK; ZIAUR RAHMAN KHAN; MOHAMMAD ABUL; KALAM AZAD; JAKIR AHMED CHOWDHURY; SELIM REZA

    This investigation describes the preparation and in vitro evaluation of gastroretentive floating tablet of theophylline. Two hydrophilic cellulose derivatives, Methocel K100M and Methocel K15MCR were evaluated for their gel forming and release controlling properties. Sodium bicarbonate and citric acid were incorporated as gas generating agents. The effects of soluble components (sodium bicarbonate and citric acid), gel forming agents and amount

  16. Preparation and In vitro Evaluation of Theophylline Loaded Gastroretentive Floating Tablets of METHOCEL K4M

    Microsoft Academic Search

    Ferdous Khan; Kazi Rashidul Azam; Sams Mohammad Anowar Sadat

    2008-01-01

    This investigation describes the preparation and in vitro evaluation of gastroretentive floating tablets of theophylline. Hydrophilic polymer METHOCEL K4M was used for its gel forming and release controlling properties. Sodium bicarbonate and citric acid were incorporated as gas generating agents. The effects of soluble components (sodium bicarbonate and citric acid), gel forming agent (METHOCEL K4M) and dose variation on drug

  17. A modified emulsion gelation technique to improve buoyancy of hydrogel tablets for floating drug delivery systems.

    PubMed

    Yom-Tov, Ortal; Seliktar, Dror; Bianco-Peled, Havazelet

    2015-10-01

    The use of buoyant or floating hydrogel tablets is of particular interest in the sustained release of drugs to the stomach. They have an ability to slow the release rates of drugs by prolonging their absorption window in the upper part of the gastrointestinal (GI) tract. In this study we synthesized bioactive hydrogels that have sustainable release rates for drugs in the stomach based on a hydrogel preparation technique that employs emulsifying surfactants. The emulsion gelation technique, which encapsulates oil droplets within the hydrogels during crosslinking, was used to decrease their specific gravity in aqueous environments, resulting in floating drug release depots. Properties such as swelling, buoyancy, density and drug release were manipulated by changing the polymer concentrations, surfactant percentages and the oil:polymer ratios. The relationship between these properties and the hydrogel's floating lag time was documented. The potential for this material to be used as a floating drug delivery system was demonstrated. PMID:26117764

  18. Floating-point sparse matrix-vector multiply for FPGAs

    Microsoft Academic Search

    Michael deLorimier; André DeHon

    2005-01-01

    Large, high density FPGAs with high local distributed memory bandwidth surpass the peak floating-point performance of high-end, general-purpose processors. Microprocessors do not deliver near their peak floating-point performance on efficient algorithms that use the Sparse Matrix-Vector Multiply (SMVM) kernel. In fact, it is not uncommon for microprocessors to yield only 10--20% of their peak floating-point performance when computing SMVM. We

  19. Formulation, release characteristics and bioavailability of novel monolithic hydroxypropylmethylcellulose matrix tablets containing acetaminophen

    Microsoft Academic Search

    Qing-Ri Cao; Yun-Woong Choi; Jing-Hao Cui; Beom-Jin Lee

    2005-01-01

    Effect of incorporating pharmaceutical excipients on the in vitro release profiles and the release mechanism of monolithic hydroxypropylmethylcellulose (4000 cps) matrix tablets (m-HPMC tablets) in terms of mimicking the dual drug release character of bi-layered Tylenol® ER tablets was studied. We also compared the in vitro release profiles of optimized m-HPMC matrix tablet and Tylenol® ER tablet in water, pH

  20. Gamma scintigraphic study of the hydrodynamically balanced matrix tablets of Metformin HCl in rabbits

    PubMed Central

    Razavi, Mahboubeh; Karimian, Hamed; Yeong, Chai Hong; Sarji, Sazilah Ahmad; Chung, Lip Yong; Nyamathulla, Shaik; Noordin, Mohamed Ibrahim

    2015-01-01

    The purpose of this study is to evaluate the in vitro and in vivo performance of gastro-retentive matrix tablets having Metformin HCl as model drug and combination of natural polymers. A total of 16 formulations were prepared by a wet granulation method using xanthan, tamarind seed powder, tamarind kernel powder and salep as the gel-forming agents and sodium bicarbonate as a gas-forming agent. All the formulations were evaluated for compendial and non-compendial tests and in vitro study was carried out on a USP-II dissolution apparatus at a paddle speed of 50 rpm. MOX2 formulation, composed of salep and xanthan in the ratio of 4:1 with 96.9% release, was considered as the optimum formulation with more than 90% release in 12 hours and short floating lag time. In vivo study was carried out using gamma scintigraphy in New Zealand White rabbits, optimized formulation was incorporated with 10 mg of 153Sm for labeling MOX2 formulation. The radioactive samarium oxide was used as the marker to trace transit of the tablets in the gastrointestinal tract. The in vivo data also supported retention of MOX2 formulation in the gastric region for 12 hours and were different from the control formulation without a gas and gel forming agent. It was concluded that the prepared floating gastro-retentive matrix tablets had a sustained-release effect in vitro and in vivo, gamma scintigraphy played an important role in locating the oral transit and the drug-release pattern. PMID:26124637

  1. The effect of chemical heterogeneity of HPMC on polymer release from matrix tablets

    Microsoft Academic Search

    Anna Viridén; Bengt Wittgren; Thomas Andersson; Anette Larsson

    2009-01-01

    Polymer release from hydrophilic matrix tablets, composed of hydroxypropyl methylcellulose, was studied for seven different polymer batches. A time difference of more than 80h between fully dissolved tablets was noticed although the batches were of the same pharmaceutical substituent (USP 2208) and viscosity (100 cps) grade. To find the functionality related parameters for polymer release from hydrophilic matrix tablets the

  2. Floating tablets for controlled release of ofloxacin via compression coating of hydroxypropyl cellulose combined with effervescent agent.

    PubMed

    Qi, Xiaole; Chen, Haiyan; Rui, Yao; Yang, Fengjiao; Ma, Ning; Wu, Zhenghong

    2015-07-15

    To prolong the residence time of dosage forms within gastrointestinal trace until all drug released at desired rate was one of the real challenges for oral controlled-release drug delivery system. Herein, we developed a fine floating tablet via compression coating of hydrophilic polymer (hydroxypropyl cellulose) combined with effervescent agent (sodium bicarbonate) to achieve simultaneous control of release rate and location of ofloxacin. Sodium alginate was also added in the coating layer to regulate the drug release rate. The effects of the weight ratio of drug and the viscosity of HPC on the release profile were investigated. The optimized formulations were found to immediately float within 30s and remain lastingly buoyant over a period of 12h in simulated gastric fluid (SGF, pH 1.2) without pepsin, indicating a satisfactory floating and zero-order drug release profile. In addition, the oral bioavailability experiment in New Zealand rabbits showed that, the relative bioavailability of the ofloxacin after administrated of floating tablets was 172.19%, compared to marketed common release tablets TaiLiBiTuo(®). These results demonstrated that those controlled-released floating tables would be a promising gastro-retentive delivery system for drugs acting in stomach. PMID:25956047

  3. Research paper Pore shape in the sodium chloride matrix of tablets after the addition

    E-print Network

    van Vliet, Lucas J.

    in the strength of the sodium chloride matrix. Fur- ther measurements on the pore size distribution ledResearch paper Pore shape in the sodium chloride matrix of tablets after the addition of starch made of sodium chloride only and tablets made of a mixture of sodium chloride (97.5% v/v) and starch (2

  4. Use of Propranolol-Magnesium Aluminium Silicate Intercalated Complexes as Drug Reservoirs in Polymeric Matrix Tablets

    PubMed Central

    Pongjanyakul, T.; Rojtanatanya, S.

    2012-01-01

    The objective of the present study was to investigate the use of propranolol–magnesium aluminium silicate intercalated complexes as drug reservoirs in hydroxypropylmethylcellulose tablets. The matrix tablets containing the complexes were prepared and characterised with respect to propranolol release and were subsequently compared with those loading propranolol or a propranolol–magnesium aluminium silicate physical mixture. Additionally, the effects of varying viscosity grades of hydroxypropyl methylcellulose, compression pressures and calcium acetate incorporation on the drug release characteristics of the complex-loaded tablets were also examined. The results showed that the complex-loaded tablets have higher tablet hardness than those containing propranolol or a physical mixture. The drug release from the complex-loaded tablets followed a zero-order release kinetic, whereas an anomalous transport was found in the propranolol or physical mixture tablets. The drug release rate of the complex tablet significantly decreased with increasing hydroxypropylmethylcellulose viscosity grade. Increase in the compression pressure caused a decrease in the drug release rate of the tablets. Furthermore, the incorporation of calcium ions could accelerate propranolol release, particularly in acidic medium, because calcium ions could be exchanged with propranolol molecules intercalated in the silicate layers of magnesium aluminium silicate. These findings suggest that propranolol-magnesium aluminium silicate intercalated complexes show strong potential for use as drug reservoirs in matrix tablets intended for modifying drug release. PMID:23626384

  5. Investigation of critical polymer properties for polymer release and swelling of HPMC matrix tablets

    Microsoft Academic Search

    Anna Viridén; Bengt Wittgren; Anette Larsson

    2009-01-01

    Four different HPMC batches were characterized to investigate properties related to critical functionality for their use in hydrophilic matrix tablets. In this study, the HPMC batches were chemically characterized and correlated to the behaviour of pure HPMC tablets. Parameters such as the molecular weight, viscosity, intrinsic viscosity and radius of gyration were kept in a rather limited range, which resulted

  6. Floating-Point Sparse Matrix-Vector Multiply for FPGAs Michael deLorimier

    E-print Network

    DeHon, André

    , it is not uncommon for micro- processors to yield only 10­20% of their peak floating-point performance when computing, Design, Experimentation Keywords Floating Point, FPGA, Reconfigurable Architecture, Sparse Matrix- vantage of matrix locality to perform much less communi- cation on parallel machines than their dense

  7. Formulation, release characteristics and bioavailability of novel monolithic hydroxypropylmethylcellulose matrix tablets containing acetaminophen.

    PubMed

    Cao, Qing-Ri; Choi, Yun-Woong; Cui, Jing-Hao; Lee, Beom-Jin

    2005-11-28

    Effect of incorporating pharmaceutical excipients on the in vitro release profiles and the release mechanism of monolithic hydroxypropylmethylcellulose (4000 cps) matrix tablets (m-HPMC tablets) in terms of mimicking the dual drug release character of bi-layered Tylenol ER tablets was studied. We also compared the in vitro release profiles of optimized m-HPMC matrix tablet and Tylenol ER tablet in water, pH 1.2 gastric fluid, and pH 6.8 intestinal fluid, and in vivo drug bioavailabilities in healthy human volunteers. Acetaminophen was used as the model drug. The m-HPMC tablets were prepared using a wet granulation method followed by direct compression. Release profiles and swelling rates of m-HPMC tablets were found to be highly influenced by the types and amounts of pharmaceutical excipients incorporated. Starch 1500 (Prejel) and sodium lauryl sulfate (SLS) played a key role in determining the dissolution rate of m-HPMC tablets. Additional excipients, i.e., microcrystalline cellulose (Avicel PH101) and NaH2PO4 were used to tune the release profiles of m-HPMC tablets. The effect of pharmaceutical excipients on drug release from HPMC-based matrix tablets was found to be mainly due to a change in hydrophilic gel expansion and on physical interactions between the drug and HPMC. The optimized m-HPMC tablet with a balanced ratio of Prejel, SLS, Avicel PH101, and NaH2PO4 in the formulation showed dual release profiles in water, pH 1.2 gastric fluid, and pH 6.8 intestinal fluid in vitro. Dual release was defined as immediate drug release within few minutes followed by extended release over 8 h. The similarity factors of m-HPMC tablets and bi-layered Tylenol ER tablets were 79.8, 66.1, and 82.7 in water, gastric fluid and intestinal fluid, respectively, indicating the equivalence of the two release profiles. No significant in vivo bioavailability differences were observed in healthy human volunteers. The developed m-HPMC tablet with dual release characteristics can be easily prepared using a conventional high-speed tablet machine and could provide an alternative to commercially available bilayered Tylenol ER tablets. PMID:16154656

  8. Huoxue Rongluo Tablet reduces matrix metalloproteinase-9 expression in infarcted brain tissue

    PubMed Central

    Zhou, Desheng; Li, Mei; Hu, Hua; Chen, Yao; Yang, Yang; Zhong, Jie; Liu, Lijuan

    2013-01-01

    Huoxue Rongluo Tablet was made of tall gastrodis tuber, dahurian angelica root, honeysuckle stem, grassleaf sweetflag rhizome, common flowering quince fruit, figwort root, red peony root and peach seed at a ratio of 3:2:6:2:3:3:3:3. Huoxue Rongluo Tablet is a well-established and common pre-scription for the treatment of cerebral infarction. In this study, a rat model of cerebral ischemia was established and the animals were intragastrically administered Huoxue Rongluo Tablet. This treat-ment reduced infarct volume, decreased matrix metalloproteinase-9 expression, and improved neurological function. Moreover, the effects of Huoxue Rongluo Tablet were better than those of buflomedil pyridoxal phosphate. These results indicate that Huoxue Rongluo Tablet is effective in treating cerebral infarction by regulating matrix metalloproteinase-9 protein expression. PMID:25206642

  9. Huoxue Rongluo Tablet reduces matrix metalloproteinase-9 expression in infarcted brain tissue.

    PubMed

    Zhou, Desheng; Li, Mei; Hu, Hua; Chen, Yao; Yang, Yang; Zhong, Jie; Liu, Lijuan

    2013-12-01

    Huoxue Rongluo Tablet was made of tall gastrodis tuber, dahurian angelica root, honeysuckle stem, grassleaf sweetflag rhizome, common flowering quince fruit, figwort root, red peony root and peach seed at a ratio of 3:2:6:2:3:3:3:3. Huoxue Rongluo Tablet is a well-established and common pre-scription for the treatment of cerebral infarction. In this study, a rat model of cerebral ischemia was established and the animals were intragastrically administered Huoxue Rongluo Tablet. This treat-ment reduced infarct volume, decreased matrix metalloproteinase-9 expression, and improved neurological function. Moreover, the effects of Huoxue Rongluo Tablet were better than those of buflomedil pyridoxal phosphate. These results indicate that Huoxue Rongluo Tablet is effective in treating cerebral infarction by regulating matrix metalloproteinase-9 protein expression. PMID:25206642

  10. Evaluation of matrix type mucoadhesive tablets containing indomethacin for buccal application.

    PubMed

    Ikeuchi-Takahashi, Yuri; Sasatsu, Masanaho; Onishi, Hiraku

    2013-09-10

    Nonsteroidal anti-inflammatory drugs (NSAIDs) are administered for pain relief from oral mucositis. However, the systemic administration of NSAIDs is limited due to systemic side effects. To avoid these side effects and treat local lesions effectively, a matrix type mucoadhesive tablet was developed. A mixture of hard fat, ethylcellulose (EC) and polyethylene glycol (PEG) was used as a matrix base, and indomethacin (IMC) was used as the principal agent. In tablets consisting of hard fat, EC and IMC, the drug release was sustained. In tablets consisting of hard fat, EC, considerable amounts of PEG and IMC, the drug release was relatively increased and IMC existed as the molecular phase or in an amorphous state. The in vitro adhesive force of the tablets consisting of hard fat, EC, considerable amounts of PEG and IMC was significantly increased as compared with the tablets consisting of hard fat and IMC. A significantly high tissue concentration and significantly low plasma concentration were observed after buccal administration of this matrix type mucoadhesive tablet as compared with that after oral administration of IMC. Thus, the matrix type mucoadhesive tablet has good potential as a preparation for the treatment of pain due to oral aphtha. PMID:23791737

  11. Immunolocalization of matrix proteins in nacre lamellae and their in vivo effects on aragonitic tablet growth.

    PubMed

    Gong, Ningping; Shangguan, Junlong; Liu, Xiaojun; Yan, Zhenguang; Ma, Zhuojun; Xie, Liping; Zhang, Rongqing

    2008-10-01

    How matrix proteins precisely control the growth of nacre lamellae is an open question in biomineralization research. Using the antibodies against matrix proteins for immunolabeling and in vivo experiments, we investigate the structural and functional roles of EDTA-soluble matrix (SM) and EDTA-insoluble matrix (ISM) proteins in nacre biomineralization of the pearl oyster Pinctada fucata. Immunolabeling reveals that a SM protein, nacrein, distributes within aragonitic tablets and intertabular matrix. An ISM protein, which we named P43, has been specifically recognized by polyclonal antibodies raised against the recombinant protein of P. fucata bone morphogenetic protein 2 in immunoblot analysis. Immunolabeling indicates that P43 is localized to interlamellar sheet, and also embedded within aragonitic tablets. Although nacrein and P43 both distribute within aragonitic tablets, they function differently in aragonitic tablet growth. When nacrein is suppressed by the antibodies against it in vivo, crystal overgrowth occurs, indicating that this SM protein is a negative regulator in aragonitic tablet growth. When P43 is suppressed in vivo, the organo-mineral assemblage is disrupted, suggesting that P43 is a framework matrix. Taken together, SM and ISM proteins are indispensable factors for the growth of nacre lamellae, controlling crystal growth and constructing the framework of aragonitic tablets. PMID:18620869

  12. Floating hot-melt extruded tablets for gastroretentive controlled drug release system

    E-print Network

    Peppas, Nicholas A.

    as model drugs. Sodium bicarbonate was incorporated into the tablet formulations and the drug release. The HME tablets prepared from the powder blend containing both Eudragit® RS PO and sodium bicarbonate to the thermal decomposition of sodium bicarbonate in the softened acrylic polymers at elevated temperature

  13. Sustained release dosage forms dissolution behavior prediction: a study of matrix tablets using NIR spectroscopy.

    PubMed

    Tabasi, Simin Hassannejad; Moolchandani, Vikas; Fahmy, Raafat; Hoag, Stephen W

    2009-12-01

    The objective of this study was to predict dissolution behavior of sustained release theophylline matrix tablets using near infrared (NIR) diffuse reflectance spectroscopy and multivariate calibration models. Eudragit NE 30D was used as a granulation binder to prepare theophylline sustained release tablets. A total of 117 tablets from 5 batches containing different proportions of Eudragit NE 30D were scanned using a NIR spectrometer. The release characteristics of the tablets were investigated in the acetate buffer for 4 h. The percentage release at 1, 2, 3 and 4 h was used to build the PLS calibration models. The Mahalanobis distance in principal component space and the 2nd derivative transformation were used for sample selection prior to building a four 4-factor partial least square (PLS) calibration models for predicting 1, 2, 3 and 4 h release rates. For PLS(1h), the standard error of calibration (SEC), and standard error of prediction (SEP) were 2.8 and 3.4%. For PLS(2h), the SEC and SEP were 2.7 and 3.5%. For PLS(3h), the SEC and SEP were 2.6 and 3.5% and for PLS(4h), the SEC and SEP were 3.0 and 3.5%, respectively. For the first time, NIR spectroscopy was successfully applied to predict drug release in the matrix tablets by correlating dissolution profile of each batch to its corresponding Eudragit NE 30D variation in tablet composition. PMID:19660535

  14. The Role of Oral Controlled Release Matrix Tablets in Drug Delivery Systems

    PubMed Central

    Nokhodchi, Ali; Raja, Shaista; Patel, Pryia; Asare-Addo, Kofi

    2012-01-01

    Formulations that are able to control the release of drug have become an integral part of the pharmaceutical industry. In particular oral drug delivery has been the focus of pharmaceutical research for many years. This type of drug delivery has been at the centre of research due to its many benefits over conventional dosage. The focus of this review is on matrix tablets due to their widely use and simplicity of the formulation. This includes the discussion of various types of matrix tablets and factors affecting the drug release from these formulations. The mechanism of drug release from HPMC matrices is also discussed. PMID:23678458

  15. Design and Development of Polyethylene Oxide Based Matrix Tablets for Verapamil Hydrochloride

    PubMed Central

    Vidyadhara, S.; Sasidhar, R. L. C.; Nagaraju, R.

    2013-01-01

    In the present investigation an attempt has been made to increase therapeutic efficacy, reduced frequency of administration and improved patient compliance by developing controlled release matrix tablets of verapamil hydrochloride. Verapamil hydrochloride was formulated as oral controlled release matrix tablets by using the polyethylene oxides (Polyox WSR 303). The aim of this study was to investigate the influence of polymer level and type of fillers namely lactose (soluble filler), swellable filler (starch 1500), microcrystalline cellulose and dibasic calcium phosphate (insoluble fillers) on the release rate and mechanism of release for verapamil hydrochloride from matrix tablets prepared by direct compression process. Higher polymeric content in the matrix decreased the release rate of drug. On the other hand, replacement of lactose with anhydrous dibasic calcium phosphate and microcrystalline cellulose has significantly retarded the release rate of verapamil hydrochloride. Biopharmaceutical evaluation of satisfactory formulations were also carried out on New Zealand rabbits and parameters such as maximum plasma concentration, time to reach peak plasma concentration, area under the plasma concentration time curve(0-t) and area under first moment curve(0-t) were determined. In vivo pharmacokinetic study proves that the verapamil hydrochloride from matrix tablets showed prolonged release and were be able to sustain the therapeutic effect up to 24 h. PMID:24019567

  16. Formulation and Quality Determination of Indapamide Matrix Tablet: A Thiazide Type Antihypertensive Drug

    PubMed Central

    Tazri, Jannatun; Moghal, Md. Mizanur Rahman; Dewan, Syed Masudur Rahman; Noor, Wahiduzzaman; Mohammad, Nor

    2014-01-01

    Purpose: The present study was explored to develop a sustained release matrix tablet of Indapamide, a low-dose thiazide-type diuretic, using hydroxylpropyl methylcellulose (Methocel K15MCR) in various proportions as release controlling factor. Methods: The tablets were formulated using direct compression method. The powers for tableting were evaluated for angle of response, loose bulk density, tapped bulk density, compressibility index, total porosity and drug content etc. The tablets were subjected to thickness, weight variation test, drug content, hardness, friability, and in vitro dissolution studies. Results: The granules showed satisfactory flow properties, compressibility index, and drug content. All the formulated tablets complies pharmacopoeia specifications. The release kinetics of the drug decreased exponentially with the addition of polymer concentration. Indapamide release rate was observed to be the highest with the lowest concentration of polymer used. The release mechanism was explored with zero order, first order, Higuchi and Krosmeyer equations. Stability tests of the drug showed no notable changes in the rate of drug release, related substances and drug content. Conclusion: In the context, it can be suggested that this formulation of sustained release Indapamide tablets can be marketed to treat patients with hypertension ensuring proper healthcare. PMID:24511484

  17. Formulation and evaluation of sustained release matrix tablet of rabeprazole using wet granulation technique

    PubMed Central

    Khan, Ruqaiyah; Ashraf, Md Shamim; Afzal, Muhammad; Kazmi, Imran; Jahangir, Mohammed Asadullah; Singh, Rajbala; Chandra, Ramesh; Anwar, Firoz

    2014-01-01

    Introduction: Rabeprazole, a member of substituted benzimidazoles, inhibits the final step in gastric acid secretions. This drug claims to cause fastest acid separation (due to higher pKa), and more rapidly converts to the active species to aid gastric mucin synthesis. The most significant pharmacological action of Rabeprazole is dose dependent suppression of gastric acid secretion; without anticholinergic or H2-blocking action. It completely abolishes the hydrochloric acid secretion as it is powerful inhibitor of gastric acid. Rabeprazole is acid labile and hence commonly formulated as an enteric coated tablet. The absorption of rabeprazole occurs rapidly as soon as tablet leaves the stomach. Aim: In the present study an attempt was made to formulate and evaluate Rabeprazole sustained release matrix tablet using wet granulation technique incorporating various polymers like HPMC-E15, Carbopol934, and sodium carboxymethyl cellulose (CMC). Materials and Methods: The Formulated tablets were evaluated for different physicochemical properties like rheological properties, weight variation, thickness, hardness, % friability, in vitro release studies and drug content. Results: Studies revealed that all the physicochemical parameters comply with the official standards. The in vitro release studies exhibits the release up to 90%, over a prolonged period of time which confirms the extended release profile of formulation, having better bioavailability as well as decreased dosing frequency with reduced doses. Conclusion: The sustained release matrix tablets of rabiprazole shown better bioavailability, efficacy and potency, when compared with official standards. PMID:25035637

  18. Pore shape in the sodium chloride matrix of tablets after the addition of starch as a second component

    Microsoft Academic Search

    Yu San Wu; Henderik W. Frijlink; Lucas J. van Vliet; Kees van der Voort Maarschalk

    2008-01-01

    The present research aims to test the hypothesis that the addition of a minor component causes a change in pore shape in the matrix of the primary component, causing a decrease in mechanical strength. Tablets made of sodium chloride only and tablets made of a mixture of sodium chloride (97.5% v\\/v) and starch (2.5% v\\/v) were compared. Tablets were subjected

  19. Single and Dual Drug Release Patterns from Shellac Wax-Lutrol Matrix Tablets Fabricated with Fusion and Molding Techniques

    PubMed Central

    Phaechamud, T.; Choncheewa, C.

    2015-01-01

    The objective of this investigation was to prepare the shellac wax matrix tablets by fusion and molding technique incorporated with Lutrol in different ratios to modify the hydrophobicity of matrix tablet. The matrix tablets with single drug were loaded either with propranolol hydrochloride or hydrochlorothiazide as hydrophilic and hydrophobic model drugs, and a dual drug formula was also prepared. The single and dual drug release patterns were studied in a dissolution apparatus using distilled water as medium. Propranolol hydrochloride released from matrix was easier than hydrochlorothiazide. Drug release from shellac wax matrix could be enhanced by incorporation of Lutrol. However retardation of drug release from some matrix tablets was evident for the systems that could form dispersion in the dissolution medium. The gel network from high content of Lutrol was hexagonal which was a dense and more compact structure than the other structures found when low amounts of Lutrol were present in the formula. Therefore, the formulae with high content of Lutrol could prolong drug release more efficiently than those containing low content of Lutrol. Hence shellac wax matrix could modulate the drug release with the addition of Lutrol. Sustainable dual drug release was also obtained from these developed matrix tablets. Thus shellac wax-Lutrol component could be used as a potential matrix tablet prepared with fusion and molding technique with excellent controlled drug release. PMID:25767320

  20. Simultaneous probing of swelling, erosion and dissolution by NMR-microimaging—Effect of solubility of additives on HPMC matrix tablets

    Microsoft Academic Search

    Farhad Tajarobi; Susanna Abrahmsén-Alami; Anders S. Carlsson; Anette Larsson

    2009-01-01

    Extensive studies of extended release tablets based on hydrophilic polymers have illuminated several aspects linked to their functionality. However, in some respects key factors affecting the mechanisms of release are yet unexplored. In the present study, a novel NMR-microimaging method has been used to study the influence of the solubility of additives in extended release hydroxypropyl methylcellulose (HPMC) matrix tablets.

  1. Influence of the viscosity grade and the particle size of HPMC on metronidazole release from matrix tablets

    Microsoft Academic Search

    María Elena Campos-Aldrete; Leopoldo Villafuerte-Robles

    1997-01-01

    Matrix tablets of metronidazole with hydroxypropyl methylcellulose (HPMC) were prepared by granulation with water and compaction at 127 MPa in a hydraulic press. The release profile of the obtained tablets was evaluated with the USP 23 apparatus 2 (paddle) at 100 rpm and using 0.1 N HCl as the medium. The influence of the HPMC viscosity grade and particle size

  2. Preparation and characterization of Compritol 888 ATO matrix tablets for the sustained release of diclofenac sodium.

    PubMed

    Roberts, Matthew; Pulcini, Lia; Mostafa, Shabbir; Cuppok-Rosiaux, Yvonne; Marchaud, Delphine

    2015-06-01

    The preparation of lipophilic matrix tablets for the sustained release of water soluble drugs via direct compression is not always feasible due to poor flow and rapid drug release. The aim was to evaluate the potential for developing sustained-release diclofenac sodium tablets, using Compritol® 888 ATO as a lipid matrix, by a wet granulation technique. The effects of wet granulation method (planetary mixer and fluid-bed) and liquid binder type (HPMC Metolose® 603, 606 or 615) on weight uniformity, tensile strength and release rates were investigated. The influence of compression force and speed during tablet manufacture under simulated rotary press production conditions were also evaluated. Rapid release of diclofenac sodium from directly compressed matrices was observed. A wet granulation technique using different HPMC binders produced free-flowing granules and matrices which released diclofenac sodium in a sustained manner over several hours. When the formulation comprising the lowest viscosity grade HPMC (Metolose® 603) was further evaluated using a laboratory scale fluid-bed system, consistently sized granules with good flowability and matrices with good weight uniformity and tensile strengths were produced. Release rates were consistent over a range of compression speeds and forces indicating the suitability of the formulation for production on a rotary tablet press. PMID:24354893

  3. A comprehensive in vitro and in vivo evaluation of thiolated matrix tablets as a gastroretentive delivery system.

    PubMed

    Senyigit, Zeynep Ay; Vetter, Anja; Guneri, Tamer; Bernkop-Schnürch, Andreas

    2011-08-01

    The aim of this study was to investigate the potential of thiolated matrix tablets for gastroretentive delivery systems. Poly(acrylic acid)-cysteine (PAA-Cys) and chitosan-4-thiobuthylamidine (chitosan-TBA) were evaluated as anionic and cationic thiolated polymers and riboflavin was used as a model drug. Tablets were prepared by direct compression and each formulation was characterized in terms of disintegration, swelling, mucoadhesion, and drug release properties. Thereafter, the gastric residence times of tablets were determined with in vivo study in rats. The resulting PAA-Cys and chitosan-TBA conjugates displayed 172.80 ± 30.33 and 371.11 ± 72.74 µmol free thiol groups, respectively. Disintegration studies demonstrated the stability of thiolated tablets up to 24 h, whereas tablets prepared with unmodified PAA and chitosan disintegrated within a time period of 1 h. Mucoadhesion studies showed that mucoadhesion work of PAA-Cys and chitosan-TBA tablets were 1.341- and 2.139-times higher than unmodified ones. The mucoadhesion times of PAA, PAA-Cys, chitosan, and chitosan-TBA tablets were 1.5 ± 0.5, 21 ± 1, 1 ± 0.5, 17 ± 1 h, respectively. These results confirm the theory that thiol groups react with mucin glycoproteins and form covalent bonds to the mucus layer. Release studies indicated that a controlled release was provided with thiolated tablets up to 24 h. These promising in vitro results of thiolated tablets were proved with in vivo studies. The thiolated tablets showed a gastroretention time up to 6 h, whereas unmodified tablets completely disintegrated within 1 h in rat stomach. Consequently, the study suggests that thiolated matrix tablets might be promising formulations for gastroretentive delivery systems. PMID:21463156

  4. Comparative release profile of sustained release matrix tablets of verapamil HCl

    PubMed Central

    Mathur, Vikas; Nagpal, Kalpana; Singh, Shailendra Kumar; Mishra, Dina Nath

    2013-01-01

    Introduction: Verapamil hydrochloride (VH) is a calcium channel blocking agent used in the treatment of hypertension, cardiac arrhythmia and angina pectoris. The short half-life and high frequency of administration of VH makes it a suitable candidate for designing sustained drug delivery system. The aim of the present investigation was to develop a sustained release matrix tablet of verapamil hydrochloride (VH) using ethyl cellulose, methyl cellulose, Eudragit RS 100, hydroxypropyl methylcellulose and carboxymethyl cellulose and to evaluate the drug release kinetics. Materials and Methods: In order to achieve the required sustained release profile, the tablets were prepared by a wet granulation method using avicel PH 101 and magnesium stearate as binder and lubricant, respectively. Results: The formulated tablets were characterized for pre-compression and post-compression parameters and they were in the acceptable limits. The drug release data obtained after an in vitro dissolution study was fitted to various release kinetic models in order to evaluate the release mechanism and kinetics. The criterion for selecting the best fit model was linearity (coefficient of correlation). Drug release mechanism was found to follow a complex mixture of diffusion, swelling and erosion. Furthermore, to minimize the initial burst drug release, batches were coated by using Eudragit RS100 polymer. After coating the tablets, a better release profile of the formulated tablets was expected and the release rate of the drug was compared with the marketed SR tablet of VH. Conclusion: The dosage form holds the potential to control the release rate of drug and extend the duration of action of a drug. PMID:23799207

  5. Evaluation of the swelling behaviour of iota-carrageenan in monolithic matrix tablets.

    PubMed

    Kelemen, András; Buchholcz, Gyula; Sovány, Tamás; Pintye-Hódi, Klára

    2015-08-10

    The swelling properties of monolithic matrix tablets containing iota-carrageenan were studied at different pH values, with measurements of the swelling force and characterization of the profile of the swelling curve. The swelling force meter was linked to a PC by an RS232 cable and the measured data were evaluated with self-developed software. The monitor displayed the swelling force vs. time curve with the important parameters, which could be fitted with an Analysis menu. In the case of iota-carrageenan matrix tablets, it was concluded that the pH and the pressure did not influence the swelling process, and the first section of the swelling curve could be fitted by the Korsmeyer-Peppas equation. PMID:25966465

  6. Biphasic release of indomethacin from HPMC\\/pectin\\/calcium matrix tablet: II. Influencing variables, stability and pharmacokinetics in dogs

    Microsoft Academic Search

    Baojian Wu; Daoyin Deng; Yi Lu; Wei Wu

    2008-01-01

    The pectin\\/calcium interaction, which is the basis for biphasic release of indomethacin from the HPMC\\/pectin\\/calcium chloride matrix tablet, is susceptible to influence of a variety of variables that is supposed to be encountered by the oral route. In this study, the effect of influencing variables on biphasic release characteristics, the stability and the pharmacokinetics of the hybrid matrix tablet were

  7. Scalable and Modular Algorithms for Floating-Point Matrix Multiplication on FPGAs

    Microsoft Academic Search

    Ling Zhuo; Viktor K. Prasanna

    2004-01-01

    The abundant hardware resources on current FPGAs provide new opportunities to improve the performance of hardware implementations of scientific computations. In this paper, we propose two FPGA-based algorithms for floating-point matrix multiplication, a fundamental kernel in a number of scientific applications. We analyze the de- sign tradeoffs in implementing this kernel on FPGAs. Our algorithms employ a linear array architecture

  8. Design and evaluation of matrix-based controlled release tablets of diclofenac sodium and chondroitin sulphate

    Microsoft Academic Search

    Amelia Avachat; Vikram Kotwal

    2007-01-01

    The purpose of the present study was to develop and characterize an oral controlled release drug delivery system for concomitant\\u000a administration of diclofenac sodium (DS) and chondroitin sulfate (CS). A hydrophilic matrix-based tablet using different concentrations\\u000a of hydroxypropylmethylcellulose (HPMC) was developed using wet granulation technique to contain 100 mg of DS and 400 mg of\\u000a CS. Formulations prepared were evaluated

  9. Influence of ?-cyclodextrin complexation on carbamazepine release from hydroxypropyl methylcellulose matrix tablets

    Microsoft Academic Search

    Let??cia S Koester; Clarissa R Xavier; Paulo Mayorga; Valquiria L Bassani

    2003-01-01

    The in vitro release profiles of carbamazepine and ?-cyclodextrin either complexed or simply mixed and subsequently incorporated in hydrophilic matrix tablets containing 15 or 30% hydroxypropyl methylcellulose were evaluated. Solubility studies revealed a linear relationship between the increase in carbamazepine solubility and the increase in ?-cyclodextrin concentration. Drying methods (spray-drying and freeze-drying) were used to obtain carbamazepine\\/?-cyclodextrin solid complexes in

  10. Direct analysis of pharmaceutical tablet formulations using Matrix-Assisted Laser Desorption/Ionisation Mass Spectrometry Imaging.

    PubMed

    Earnshaw, Caroline J; Carolan, Vikki A; Richards, Don S; Clench, Malcolm R

    2010-06-15

    Matrix-Assisted Laser Desorption/Ionisation Mass Spectrometry Imaging (MALDI MSI) has been used to directly analyse a range of tablets in order to assess the homogeneity of the active drug compound throughout the excipients contained within the tablets studied. The information gained from the imaging experiments can be used to improve and gain a greater understanding of the manufacturing process; such knowledge will enable improvements in finished product quality to make safer and more efficacious tablet formulations. Commercially available and prescription tablet formulations have been analysed, including aspirin, paracetamol, sildenafil citrate (Viagra(R)) and a batch of tablets in development (tablet X: placebo; 1 mg; 3 mg and 6 mg). MALDI MSI provides semi-quantitative information that is related to ion abundance, therefore Principal Component Analysis (PCA), a multivariate analysis technique, has been used to differentiate between tablets containing different amounts of active drug ingredient. Aspects of sample preparation have also been investigated with regard to tablet shape and texture. The results obtained indicate that MALDI MSI can be used effectively to analyse the spatial distribution of the active pharmaceutical component (API) in pharmaceutical tablet formulations. PMID:20486264

  11. Statistical Optimization of Sustained Release Venlafaxine HCI Wax Matrix Tablet

    PubMed Central

    Bhalekar, M. R.; Madgulkar, A. R.; Sheladiya, D. D.; Kshirsagar, S. J.; Wable, N. D.; Desale, S. S.

    2008-01-01

    The purpose of this research was to prepare a sustained release drug delivery system of venlafaxine hydrochloride by using a wax matrix system. The effects of bees wax and carnauba wax on drug release profile was investigated. A 32 full factorial design was applied to systemically optimize the drug release profile. Amounts of carnauba wax (X1) and bees wax (X2) were selected as independent variables and release after 12 h and time required for 50% (t50) drug release were selected as dependent variables. A mathematical model was generated for each response parameter. Both waxes retarded release after 12 h and increases the t50 but bees wax showed significant influence. The drug release pattern for all the formulation combinations was found to be approaching Peppas kinetic model. Suitable combination of two waxes provided fairly good regulated release profile. The response surfaces and contour plots for each response parameter are presented for further interpretation of the results. The optimum formulations were chosen and their predicted results found to be in close agreement with experimental findings. PMID:20046773

  12. Formulation and Evaluation of Cefixime Trihydrate Matrix Tablets Using HPMC, Sodium CMC, Ethyl Cellulose.

    PubMed

    Sirisolla, Janakidevi; Ramanamurthy, K V

    2015-01-01

    The objective of the present work is to design sustained release matrix tablets of cefixime trihydrate by incorporating drug in a matrix made up of release retardant polymers, which prolong drug release leading to minimization of the peak and valley effect in the plasma and provide patient convenience. The effect of combination of polymers on parameters like release pattern, release mechanism of the drug were studied. Total nine formulations each containing 200 mg of drug were prepared by direct compression method. The formulations F-1, F-2, F-3 were prepared with a 1:1 drug to polymer ratio using hydroxypropyl methylcellulose, carboxymethyl cellulose sodium and ethyl cellulose. F-4 was prepared with a 1:1 ratio of hydroxypropyl methylcellulose, carboxymethyl cellulose sodium, F-5 as prepared with a 1:1 ratio of hydroxypropyl methylcellulose and ethyl cellulose, F-6 was prepared with a 1:1 ratio of carboxymethyl cellulose sodium and ethyl cellulose, F-7, F-8, F-9 were prepared by using polymers hydroxypropyl methylcellulose, carboxymethyl cellulose sodium and ethyl cellulose in the ratios of 0.5:0.5:1, 0.5:1:0.5, and 1:0.5:0.5. Designed matrix tablets were evaluated for various pre-compression and post-compression parameters. Formulation F-5 showed 102.15 % release at the end of 12 h and it is selected as the best formulation. All Formulations followed zero order with non-Fickian diffusion method. PMID:26180278

  13. Formulation and Evaluation of Cefixime Trihydrate Matrix Tablets Using HPMC, Sodium CMC, Ethyl Cellulose

    PubMed Central

    Sirisolla, Janakidevi; Ramanamurthy, K. V.

    2015-01-01

    The objective of the present work is to design sustained release matrix tablets of cefixime trihydrate by incorporating drug in a matrix made up of release retardant polymers, which prolong drug release leading to minimization of the peak and valley effect in the plasma and provide patient convenience. The effect of combination of polymers on parameters like release pattern, release mechanism of the drug were studied. Total nine formulations each containing 200 mg of drug were prepared by direct compression method. The formulations F-1, F-2, F-3 were prepared with a 1:1 drug to polymer ratio using hydroxypropyl methylcellulose, carboxymethyl cellulose sodium and ethyl cellulose. F-4 was prepared with a 1:1 ratio of hydroxypropyl methylcellulose, carboxymethyl cellulose sodium, F-5 as prepared with a 1:1 ratio of hydroxypropyl methylcellulose and ethyl cellulose, F-6 was prepared with a 1:1 ratio of carboxymethyl cellulose sodium and ethyl cellulose, F-7, F-8, F-9 were prepared by using polymers hydroxypropyl methylcellulose, carboxymethyl cellulose sodium and ethyl cellulose in the ratios of 0.5:0.5:1, 0.5:1:0.5, and 1:0.5:0.5. Designed matrix tablets were evaluated for various pre-compression and post-compression parameters. Formulation F-5 showed 102.15 % release at the end of 12 h and it is selected as the best formulation. All Formulations followed zero order with non-Fickian diffusion method. PMID:26180278

  14. Formulation and Evaluation of Hydroxypropyl Methylcellulose-based Controlled Release Matrix Tablets for Theophylline

    PubMed Central

    Sekharan, T. Raja; Palanichamy, S.; Tamilvanan, S.; Shanmuganathan, S.; Thirupathi, A. Thanga

    2011-01-01

    The objectives of the study were to formulate hydroxypropyl methyl cellulose-based controlled release matrix tablets for theophylline with varying drug:polymer ratios (1:1 and 1:2) and differing tablet hardness (5, 6 and 7 kg/cm2), and to evaluate the tablet's physico-chemical properties such as hardness, uniformity of weight, friability, drug content and in vitro drug release. Initially, granules were made by wet granulation technique and evaluated for angle of repose, bulk density, tapped density, bulkiness, compressibility index and hausner ratio. The results indicate good flow property of the granules and thus, the evaluated tablet physical properties were within the acceptable limits. The FT-IR study for the F-6 formulation showed that there was no interaction between the drug and the polymer. In vitro release studies were performed using Disso-2000 (paddle method) in 900 ml of pH 7.4 at 50 rpm. The result indicated that at high drug:polymer ratio (1:2) and hardness value 7 kg/cm2, prolonged drug release was observed than the low drug: polymer ratio (1:1) and hardness values (5 and 6 kg/cm2). The release kinetics was found to follow korsmeyers-peppas model and the mechanism of drug release was by non-fickian or anomalous diffusion. The F-6 formulation was chosen for stability studies. F-6 formulation was stable when it was kept at different temperatures for a period of 6 months. PMID:22707833

  15. In vitro release of ketoprofen from hydrophilic matrix tablets containing cellulose polymer mixtures.

    PubMed

    Vueba, M L; Batista de Carvalho, L A E; Veiga, F; Sousa, J J; Pina, M E

    2013-11-01

    The effect of cellulose ether polymer mixtures, containing both hydroxypropylcellulose (HPC) and hydroxypropylmethylcellulose (HPMC K15M or K100M), on ketoprofen (KTP) release from matrix tablets was investigated. In order to evaluate the compatibility between the matrix components, Raman spectroscopy, scanning electron microscopy (SEM), and X-ray powder diffraction (XRPD) experiments were performed. The results evidence the absence of significant intermolecular interactions that could eventually lead to an incompatibility between the drug and the different excipients. Formulations containing mixtures of polymers with both low and high viscosity grades were prepared by a direct compression method, by varying the polymer/polymer (w/w) ratio while keeping the drug amount incorporated in the solid dispersion constant (200 mg). The hardness values of different matrices were found within the range 113.8 to 154.9 N. HPLC analysis showed a drug content recovery between 99.3 and 102.1%, indicating that no KTP degradation occurred during the preparation process. All formulations attained a high hydration degree after the first hour, which is essential to allow the gel layer formation prior to tablet dissolution. Independent-model dissolution parameters such as t(10%) and t(50%) dissolution times, dissolution efficiency (DE), mean dissolution time (MDT), and area under curve (AUC) were calculated for all formulations. Zero-order, first-order, Higuchi, and Korsmeyer-Peppas kinetic models were employed to interpret the dissolution profiles: a predominantly Fickian diffusion release mechanism was obtained - with Korsmeyer-Peppas exponent values ranging from 0.216 to 0.555. The incorporation of HPC was thus found to play an essential role as a release modifier from HPMC containing tablets. PMID:23094867

  16. Design and in vitro/in vivo evaluation of extended release matrix tablets of nateglinide

    PubMed Central

    Sharma, Pushkar R.; Lewis, Shaila A.

    2013-01-01

    Aim Nateglinide is a quick acting anti-diabetic medication whose potent activity lasts for a short duration. One of the dangerous side effects of nateglinide administration is rapid hypoglycemia, a condition that needs to be monitored carefully to prevent unnecessary fatalities. The aim of the study was to develop a longer lasting and slower releasing formulation of nateglinide that could be administered just once daily. Methods Matrix tablets of nateglinide were prepared in combination with the polymers hydroxypropylmethylcellulose (HPMC), eudragits, ethyl cellulose and polyethylene oxide and the formulated drug release patterns were evaluated using in vitro and in vivo studies. Conclusion Of the seventeen formulated matrix tablets tested, only one formulation labelled HA-2 that contained 15% HPMC K4M demonstrated release profile we had aimed for. Further, swelling studies and scanning electron microscopic analysis confirmed the drug release mechanism of HA-2. The optimized formulation HA-2 was found to be stable at accelerated storage conditions for 3 months with respect to drug content and physical appearance. Mathematical analysis of the release kinetics of HA-2 indicated a coupling of diffusion and erosion mechanisms. In-vitro release studies and pharmacokinetic in vivo studies of HA-2 in rabbits confirmed the sustained drug release profile we had aimed for. PMID:24563597

  17. Influence of Organic Acids on Diltiazem HCl Release Kinetics from Hydroxypropyl Methyl Cellulose Matrix Tablets.

    PubMed

    Sateesha, Sb; Rajamma, Aj; Narode, Mk; Vyas, Bd

    2010-07-01

    The matrix tablets of diltiazem hydrochloride were prepared by direct compression using hydroxypropyl methyl cellulose (HPMC) and various amounts (2.5%, 5.0%, 10% and 20%) of citric acid, malic acid and succinic acid. The characterization of physical mixture of drug and organic acids was performed by Infra-red spectroscopy. An organic acid was incorporated to set up a system bringing about gradual release of this drug. The influence of organic acids on the release rate were described by the Peppas equation: M (t) /M(?) = Kt (n) and Higuchi's equation: Q (t) = K(1)t(1/2). The addition of organic acids and the pH value of medium could notably influence the dissolution behavior and mechanism of drug-release from matrices. Increasing amounts of organic acid produced an increase in drug release rate, which showed a good linear relationship between contents of organic acid and drug accumulate release (%) in phosphate buffer, pH 7.4. The drug release increased significantly (P < 0.05) with use of succinic acid in tablet formulation. Increasing amounts of succinic acid above 10% produced decreasing values of n and increasing values of k, in a linear relationship, which indicated there was a burst release of drug from the matrix. Optimized formulations are found to be stable upon 3-month study. PMID:21042476

  18. Drug Release Kinetics and Front Movement in Matrix Tablets Containing Diltiazem or Metoprolol/?-Carrageenan Complexes

    PubMed Central

    Bonferoni, Maria Cristina; Colombo, Paolo; Zanelotti, Laura; Caramella, Carla

    2014-01-01

    In this work we investigated the moving boundaries and the associated drug release kinetics in matrix tablets prepared with two complexes between ?-carrageenan and two soluble model drugs, namely, diltiazem HCl and metoprolol tartrate aiming at clarifying the role played by drug/polymer interaction on the water uptake, swelling, drug dissolution, and drug release performance of the matrix. The two studied complexes released the drug with different mechanism indicating two different drug/polymer interaction strengths. The comparison between the drug release behaviour of the complexes and the relevant physical mixtures indicates that diltiazem gave rise to a less soluble and more stable complex with carrageenan than metoprolol. The less stable metoprolol complex afforded an erodible matrix, whereas the stronger interaction between diltiazem and carrageenan resulted in a poorly soluble, slowly dissolving matrix. It was concluded that the different stability of the studied complexes affords two distinct drug delivery systems: in the case of MTP, the dissociation of the complex, as a consequence of the interaction with water, affords a classical soluble matrix type delivery system; in the case of DTZ, the dissolving/diffusing species is the complex itself because of the very strong interaction between the drug and the polymer. PMID:25045689

  19. Design and Evaluation of a Novel Floating Osmotic Pump System

    Microsoft Academic Search

    Zhihong Zhang; Bo Peng; Xinggang Yang; Chao Wang; Guangmei Sun; Weisan Pan

    Purpose. Find a novel delivery system for oral administration of drugs that have absorption window in the upper part of gastrointestinal (GI) track. Methods. Dipyridamole was chosen as the model drug. A novel system, which combined the osmotic pump controlled release system and the floating system was designed; matrix tablets (MT) were prepared for compares. The effects of pH, temperature

  20. Effect of matrix composition and process conditions on casein-gelatin beads floating properties.

    PubMed

    Bulgarelli, E; Forni, F; Bernabei, M T

    2000-04-01

    Casein-gelatin beads have been prepared by emulsification extraction method and cross-linked with D,L-glyceraldehyde in an acetone-water mixture 3:1 (v/v). Casein emulsifying properties cause air bubble incorporation and the formation of large holes in the beads. The high porosity of the matrix influences the bead properties such as drug loading, drug release and floatation. These effects have been stressed by comparison with low porous beads, artificially prepared without cavities. The percentage of casein in the matrix increases the drug loading of both low and high porous matrices, although the loading of high porous matrices is lower than that of low porous matrices. As a matter of fact, the drug should be more easily removed during washing and recovery because of the higher superficial pore area of the beads. This can explain the drug release rate increase, observed in high porous matrix, in comparison with beads without cavities. This is due to the rapid diffusion of the drug through water filled pores. The study shows that cavities act as an air reservoir and enable beads to float. Therefore, casein seems to be a material suitable to the inexpensive formation of an air reservoir for floating systems. PMID:10767565

  1. Floating Node Method and Virtual Crack Closure Technique for Modeling Matrix Cracking-Delamination Migration

    NASA Technical Reports Server (NTRS)

    DeCarvalho, Nelson V.; Chen, B. Y.; Pinho, Silvestre T.; Baiz, P. M.; Ratcliffe, James G.; Tay, T. E.

    2013-01-01

    A novel approach is proposed for high-fidelity modeling of progressive damage and failure in composite materials that combines the Floating Node Method (FNM) and the Virtual Crack Closure Technique (VCCT) to represent multiple interacting failure mechanisms in a mesh-independent fashion. In this study, the approach is applied to the modeling of delamination migration in cross-ply tape laminates. Delamination, matrix cracking, and migration are all modeled using fracture mechanics based failure and migration criteria. The methodology proposed shows very good qualitative and quantitative agreement with experiments.

  2. Floating Node Method and Virtual Crack Closure Technique for Modeling Matrix Cracking-Delamination Interaction

    NASA Technical Reports Server (NTRS)

    DeCarvalho, N. V.; Chen, B. Y.; Pinho, S. T.; Baiz, P. M.; Ratcliffe, J. G.; Tay, T. E.

    2013-01-01

    A novel approach is proposed for high-fidelity modeling of progressive damage and failure in composite materials that combines the Floating Node Method (FNM) and the Virtual Crack Closure Technique (VCCT) to represent multiple interacting failure mechanisms in a mesh-independent fashion. In this study, the approach is applied to the modeling of delamination migration in cross-ply tape laminates. Delamination, matrix cracking, and migration are all modeled using fracture mechanics based failure and migration criteria. The methodology proposed shows very good qualitative and quantitative agreement with experiments.

  3. The influence of crystallization inhibition of HPMC and HPMCAS on model substance dissolution and release in swellable matrix tablets.

    PubMed

    Tajarobi, Farhad; Larsson, Anette; Matic, Hanna; Abrahmsén-Alami, Susanna

    2011-05-01

    One of the drawbacks with solid solution systems is their thermodynamic instability in solution. Considering the release of these systems from extended-release formulations, in particular swellable matrix tablets, a successful tablet formulation can be regarded as a composition able to maintain the molecular state of the poorly soluble crystalline drug through diffusion in the matrix. This may in turn provide molecular rather than particulate delivery of the substance from the matrix. In this study, the solid state and dissolution behavior of amorphous solid dispersions of a model crystalline substance, butyl paraben in HPMC and HPMCAS, was investigated. In addition, the suitability of HPMCAS as both effective solid solution carrier and as extended-release matrix forming polymer was examined. The release from all systems investigated showed extended-release capacity with a release rate similar to the rate of matrix erosion. However, a detailed study of the factors affecting the release mechanism revealed that upon hydration, the model substance crystallized in the gel layer of the HPMC-based formulation, whereas it remained in amorphous form in the HPMCAS tablets. In the case of HPMCAS formulation, this effect was attributed to (i) the ability of this polymer to keep the model substance in a supersaturated state and (ii) the very slow matrix hydration, resulting in a steep concentration gradient of the drug substance and a short diffusion path through the matrix into the dissolution bulk. PMID:21168491

  4. In vitro controlled release of colon targeted mesalamine from compritol ATO 888 based matrix tablets using factorial design

    PubMed Central

    Patel, J.K.; Patel, N.V.; Shah, S.H.

    2009-01-01

    A controlled release matrix formulation for mesalamine was designed and developed to achieve a 24 h release profile. Using compritol 888 ATO (glyceryl behenate) as an inert matrix-forming agent to control the release of mesalamine, formulation granules containing the solid dispersions were investigated. Pectin, a polysaccharide, was used as bacterial dependent polymer for colon targeting. The matrix tablets for these formulations were prepared by direct compression and their in vitro release tests were carried out. A 32 full factorial design was used for optimization by taking the amounts of glyceryl behenate (X1) and pectin (X2) as independent variables and percentage drug released at 2 (Q2), 16 (Q16) and 24 (Q24) h as dependent variables. Drug release from the matrix tablets formulations lasted for over 24 h. Images of the tablet surface and cross-section were characterized by scanning electron microscopy to show the formed pores and channels in the matrices. These may provide the release pathway for the inner embedded drugs. The co-mixing of polysaccharide pectin, into the waxy matrices played a meaningful role in targeting the tablets to colon. The drug release from the novel formulation may be attributed to the diffusion-controlled mechanism. The results of the full factorial design indicated that an optimum amount of compritol ATO 888 and a high amount of pectin favors the colon targeting and controlled release of mesalamine from dosage form. PMID:21589801

  5. Photoimages and the release characteristics of lipophilic matrix tablets containing highly water-soluble potassium citrate with high drug loadings.

    PubMed

    Cao, Qing-Ri; Kim, Tae-Wan; Lee, Beom-Jin

    2007-07-18

    Two types of the carnauba wax-based lipophilic matrix tablet using spray-dried granules (SDT) or directly compressible powdered mixtures (DCT) were prepared for sustained release. The model drug was a highly water-soluble potassium citrate and loaded about 74% of the total tablet weight. The SDT slowly eroded and disintegrated during the release study without showing sustained release when the hydrophilic excipients were added. In contrast, the DCT was more efficient for sustained release. The release rate decreased with increasing carnauba wax concentration. In particular, the sustained release rate was markedly pronounced when the lipophilic stearyl alcohol and stearic acid were combined with the carnauba wax. The surface of the intact DCT appeared to be smooth and rusty. The DCT rose to the surface from the bottom of the vessel during the release test, and numerous pores and cracks with no signs of disintegration were also observed after the release test. The release profile was dependent on the formulation composition and preparation method of the matrix tablet. Diffusion-controlled leaching through the channels of the pores and cracks of the lipophilic matrix tablet (DCT) is a key to the sustained release. PMID:17532156

  6. Biphasic release of indomethacin from HPMC/pectin/calcium matrix tablet: II. Influencing variables, stability and pharmacokinetics in dogs.

    PubMed

    Wu, Baojian; Deng, Daoyin; Lu, Yi; Wu, Wei

    2008-05-01

    The pectin/calcium interaction, which is the basis for biphasic release of indomethacin from the HPMC/pectin/calcium chloride matrix tablet, is susceptible to influence of a variety of variables that is supposed to be encountered by the oral route. In this study, the effect of influencing variables on biphasic release characteristics, the stability and the pharmacokinetics of the hybrid matrix tablet were investigated. An increasing tendency of the overall release rate was observed from pH 1.2 to 7.4. The power law correlation n values increased with pH, while the release lag time or 10% release time (T0.1) decreased at pH 6.8 and 7.4. Ionic strength in the release media also influenced the biphasic release significantly at sodium chloride levels of over 0.5%. Obvious increase in overall release rate was observed at sodium chloride level of 0.9% with an n value of 1.20 and a T0.1 of 3.4h. At sodium chloride levels of over 2%, the pectin/calcium interaction was disrupted resulting in very fast release of indomethacin. Release in gradient pH media was similar to that in pH 6.8 citrate buffer. When pectinase (Pectinex Ultra SP-L) was added into the release medium in 22.2 pg/ml or over, obvious triggering on drug release was observed. The stress testing showed increased release at extreme relative humidity of 92.5%. Both accelerated testing for 6m and long-term testing for 12 m affirmed fine stability, especially in release characteristics. Pharmacokinetic study in dogs gave Tmax/Cmax of 4h/604 ng/ml and 3h/1662 ng/ml for HPMC/pectin/calcium and HPMC/pectin tablet, respectively. The plasma indomethacin level of the calcium-containing tablet was maintained at a much lower level for 3h with a MRT of 7.13 h, longer than 3.97 and 5.61 h for indomethacin crude drug and HPMC/pectin tablet, confirming delayed absorption. The AUC of the HPMC/pectin/calcium tablet was lower than that of the HPMC/pectin tablet and indomethacin crude drug showing incomplete absorption. It is concluded that the HPMC/pectin/calcium matrix tablet is potentially useful for colon-specific drug delivery. PMID:17988844

  7. Effect of calcium ions on the gelling and drug release characteristics of xanthan matrix tablets.

    PubMed

    Baumgartner, Sasa; Pavli, Matej; Kristl, Julijana

    2008-06-01

    Xanthan is a well-known biopolymer. It is an anionic polysaccharide, whose primary structure depends on the bacterial strain and fermentation conditions. Xanthan was extensively studied in combination with galactomannans, and over 90 patents cover the technology of this preparation. Our aim was to investigate the relation between the physical properties of a xanthan matrix in the absence or presence of calcium ions and its influence on the release of pentoxifylline. The release of pentoxifylline from xanthan tablets in purified water was shown to be very slow and governed by the process of polymer relaxation. The presence of calcium ions significantly increased the drug release, changing the release mechanism into a more diffusion controlled one. Xanthan matrices showed substantially faster and more extensive swelling in water than in the presence of Ca2+ ions. Surprisingly, negative correlation between drug release and degree of swelling was obtained for xanthan: the higher the swelling, the slower the drug release. Higher ionic strength led to lower erosion of xanthan tablets, and the gel layers formed were more rigid and of firmer texture, as shown by rheological experiments and textural profiling. The results indicate that the presence of Ca2+ ions in the solution or in matrices does not cause crosslinking of xanthan polymers, but causes charge screening of ionized groups on the trisaccharide side chains of xanthan, leading to lower inter-molecular repulsion and changing water arrangement. The understanding of the parameters influencing drug release leads to the conclusion that xanthan is suitable for controlled release formulations, especially with the incorporation of certain small counterions. PMID:18248802

  8. Matrix Effects in Quantitative Assessment of Pharmaceutical Tablets Using Transmission Raman and Near-Infrared (NIR) Spectroscopy.

    PubMed

    Sparén, Anders; Hartman, Madeleine; Fransson, Magnus; Johansson, Jonas; Svensson, Olof

    2015-05-01

    Raman spectroscopy can be an alternative to near-infrared spectroscopy (NIR) for nondestructive quantitative analysis of solid pharmaceutical formulations. Compared with NIR spectra, Raman spectra have much better selectivity, but subsampling was always an issue for quantitative assessment. Raman spectroscopy in transmission mode has reduced this issue, since a large volume of the sample is measured in transmission mode. The sample matrix, such as particle size of the drug substance in a tablet, may affect the Raman signal. In this work, matrix effects in transmission NIR and Raman spectroscopy were systematically investigated for a solid pharmaceutical formulation. Tablets were manufactured according to an experimental design, varying the factors particle size of the drug substance (DS), particle size of the filler, compression force, and content of drug substance. All factors were varied at two levels plus a center point, except the drug substance content, which was varied at five levels. Six tablets from each experimental point were measured with transmission NIR and Raman spectroscopy, and their concentration of DS was determined for a third of those tablets. Principal component analysis of NIR and Raman spectra showed that the drug substance content and particle size, the particle size of the filler, and the compression force affected both NIR and Raman spectra. For quantitative assessment, orthogonal partial least squares regression was applied. All factors varied in the experimental design influenced the prediction of the DS content to some extent, both for NIR and Raman spectroscopy, the particle size of the filler having the largest effect. When all matrix variations were included in the multivariate calibrations, however, good predictions of all types of tablets were obtained, both for NIR and Raman spectroscopy. The prediction error using transmission Raman spectroscopy was about 30% lower than that obtained with transmission NIR spectroscopy. PMID:25811389

  9. REPORT IN VITRO DISSOLUTION STUDIES OF DIFFERENT BRANDS OF SUSTAINED RELEASE DICLOFENAC SODIUM MATRIX TABLET AVAILABLE IN BANGLADESH

    Microsoft Academic Search

    ABU SHARA; SHAMSUR ROUF

    Commercially available national thirteen brands and three international brands of diclofenac sodium sustained release matrix tablets were studied in simulated gastric medium (pH 1.2) for 2 hours time period and simulated intestinal medium (pH 6.8) for 10 hours time period using USP reference dissolution apparatus. All the national and international brands complied with the USP in-vitro dissolution specification for drug

  10. Paroxetine hydrochloride controlled release POLYOX® matrix tablets: Screening of formulation variables using Plackett-Burman screening design

    Microsoft Academic Search

    Shun-Ji Jin; Yeon-Hee Yoo; Min-Soo Kim; Jeong-Soo Kim; Jeong-Sook Park; Sung-Joo Hwang

    2008-01-01

    The aim of the present study was to screen the effects of the formulation variables — POLYOX® molecular weight (X1), the ratio of POLYOX®\\/Avicel® PH102 (X2) and the amount of POLYOX® and Avicel® PH102 (X3), hardness (X4), HPMCP amount (X5), Eudragit® L100 amount (X6), and citric acid amount (X7) — on the paroxetine hydrochloride release from POLYOX® matrix tablet using

  11. Controlled Release Matrix Tablets of Zidovudine: Effect of Formulation Variables on the In Vitro Drug Release Kinetics

    Microsoft Academic Search

    Punna Rao Ravi; Udaya Kanth Kotreka; Ranendra Narayan Saha

    2008-01-01

    The purpose of this research was to design oral controlled release (CR) matrix tablets of zidovudine (AZT) using hydroxypropyl\\u000a methylcellulose (HPMC), ethyl cellulose (EC) and carbopol-971P (CP) and to study the effect of various formulation factors\\u000a on in vitro drug release. Release studies were carried out using USP type 1 apparatus in 900 ml of dissolution media. Release kinetics\\u000a were analyzed

  12. pH-independent release of a weakly basic drug from water-insoluble and -soluble matrix tablets.

    PubMed

    Streubel, A; Siepmann, J; Dashevsky, A; Bodmeier, R

    2000-06-15

    Weakly basic drugs or salts thereof demonstrate pH-dependent solubility. The resulting release from conventional matrix tablets decreases with increasing pH-milieu of the gastrointestinal tract. The aim of this study was to overcome this problem and to achieve pH-independent drug release. Two different polymers were used as matrix formers, the water-insoluble and almost unswellable ethylcellulose (EC), and the water-soluble and highly swellable hydroxypropyl methylcellulose (HPMC). Two different approaches to solve the problem of pH-dependent release of weakly basic drugs are demonstrated in this paper. The first one is based on the addition of hydroxypropyl methylcellulose acetate succinate (HPMCAS, an enteric polymer), the second one on the addition of organic acids such as fumaric, succinic or adipic acid to the drug-polymer system. The first approach failed to achieve pH-independent drug release, whereas the addition of organic acids to both matrix formers was found to maintain low pH values within the tablets during drug release in phosphate buffer (pH 6.8 or 7.4). Thus, the micro-environmental conditions for the dissolution and diffusion of the weakly basic drug were almost kept constant. The release of verapamil hydrochloride from tablets composed of ethylcellulose or HPMC and organic acids was found to be pH-independent. PMID:10773333

  13. Formulation and in vitro evaluation of theophylline matrix tablets prepared by direct compression: Effect of polymer blends.

    PubMed

    El-Bagory, Ibrahim; Barakat, Nahla; Ibrahim, Mohamed A; El-Enazi, Fouza

    2012-07-01

    The deformation mechanism of pharmaceutical powders, used in formulating directly compressed matrix tablets, affects the characteristics of the formed tablets. Three polymers of different deformation mechanisms were tested for their impact on theophylline directly compressed tablets namely Kollidon SR (KL SR, plastic deformation), Ethylcellulose (EC, elastic deformation) and Carnauba wax (CW, brittle deformation) at different compression forces. However, tablets based mainly on KL SR, the plastically deformed polymer (TN1) exhibited the highest hardness values compared to the other formulae which are based on either blends of KL SR with CW, the very brittle deformed polymer. The upper detected force for TN formulae and the lower punch force were found to dependent mainly on the powder deformation. This difference is attributed to the work done during the compression phase as well as the work lost during the decompression phase. Furthermore, the release profiles of TN from formulae TN2 and TN4 that are based on the composition (2KL SR:1EC) and (1KL SR:2EC), respectively, were consistent with different deformation mechanisms of KL SR and EC and on the physicochemical properties like the water absorptive capacity of EC. Upon increasing the weight ratio of KL SR (TN2), the release rate was greatly retarded (39.4%, 37.1%, 35.0% and 33.6% released after 8 h at 5, 10, 15 and 20 kN. PMID:24115902

  14. Formulation of bi-layer matrix tablets of tramadol hydrochloride: Comparison of rate retarding ability of the incorporated hydrophilic polymers.

    PubMed

    Arif, Hasanul; Al-Masum, Abdullah; Sharmin, Florida; Reza, Selim; Sm Islam, Sm Ashraful

    2015-05-01

    Bi-layer tablets of tramadol hydrochloride were prepared by direct compression technique. Each tablet contains an instant release layer with a sustained release layer. The instant release layer was found to release the initial dose immediately within minutes. The instant release layer was combined with sustained release matrix made of varying quantity of Methocel K4M, Methocel K15MCR and Carbomer 974P. Bi-layer tablets were evaluated for various physical tests including weight variation, thickness and diameter, hardness and percent friability. Drug release from bi-layer tablet was studied in acidic medium and buffer medium for two and six hours respectively. Sustained release of tramadol hydrochloride was observed with a controlled fashion that was characteristic to the type and extent of polymer used. % Drug release from eight-hour dissolution study was fitted with several kinetic models. Mean dissolution time (MDT) and fractional dissolution values (T25%, T50% and T80%) were also calculated as well, to compare the retarding ability of the polymers. Methocel K15MCR was found to be the most effective in rate retardation of freely water-soluble tramadol hydrochloride compared to Methocel K4M and Capbomer 974P, when incorporated at equal ratio in the formulation. PMID:26004717

  15. Studies on the compressibility of wax matrix granules of acetaminophen and their admixtures with various tableting bases.

    PubMed

    Uhumwangho, M U; Okor, R S

    2006-04-01

    Matrix granules of acetaminophen have been formed by a melt granulation process whereby the acetaminophen powder was triturated with the melted wax--goat wax, glyceryl monostearate or carnuba wax. The compressibility of the matrix granules and their admixture, with diluent granules (lactose, alpha-cellulose or microcrystalline cellulose) was investigated. The granules were compressed to tablets at a constant load (30 arbitrary units on the load scale) of a manesty single punch machine. Resulting tablets were evaluated for tensile strength (T) and disintegration times (DT). Granule flow was determined by measuring their angle of repose when allowed to fall freely on a level surface. Matrix granules prepared by melt granulation with goat wax or glyceryl monostearate were too sticky and therefore did not flow at all. They were also poorly compressible (T values = 0.20MN/m2). Inclusion of the diluent remarkably improved granule flow property and compressibility. The T values of the tablets (measure of compressibility) increased from about 0.24 to 0.65 MN/m2 during increase in diluent (lactose) content from 20 to 80 %w/w. Microcrystalline cellulose and alpha-cellulose were more effective than lactose in promoting compressibility of the granules. By contrast the matrix granules formed with carnuba wax were free flowing (angle of repose, 18.60). Addition of the diluent further improved flowability slightly. The matrix granules (without a diluent) were readily compressible (T value, 1.79MN/m2). Addition of the diluent (80%w/w) reduced T values (MN/m2) slightly to 1.32 (lactose), 1.48 (alpha-cellulose) and 1.74 (microcrystalline cellulose). Tablets of the matrix granules only, disintegrated rapidly within 3 minutes. DT was further reduced to <30 s by addition of any of the diluents. The indication is that the inclusion of the diluents studied can be used to improve the compressibility of the otherwise poorly compressible matrix granules. Based on the flowability, compressibility, and disintegration data, carnuba wax proved most promising in the melt granulation of the test drug for sustained release applications. PMID:16751119

  16. Formulation and Evaluation of Cephalexin Extended-release Matrix Tablets Using Hydroxy Propyl Methyl Cellulose as Rate-controlling Polymer

    PubMed Central

    Vijay, J; Sahadevan, JT; Prabhakaran, R; Gilhotra, R Mehra

    2012-01-01

    The present investigation reports the design and evaluation of six-hour extended release film-coated matrix tablets of cephalexin using different grades of hydrophilic polymer hydroxypropylmethylcellulose (HPMC) employing direct compression method. The preformulation studies performed included the physical compatibility studies, Differential Scanning Calorimetry analysis, drug characterization using Fourier Transform Infra Red spectroscopic analysis and particle size analysis using sieve method. The tablets were evaluated for weight variation, hardness, thickness and friability. Results of the studies indicate that the polymers used have significant release-retarding effect on the formulation. The dissolution profile comparison of the prepared batches P1 to P8 and market preparation (Sporidex AF 375) was done by using Food and Drug Administration-recommended similarity factor (f2) determination. The formulation P8 (10% HPMC K4M, 15% HPMC 15cps) with a similarity factor (f2) of 77.75 was selected as the optimized formulae for scale-up batches. The dissolution data of the best formulation P8 was fitted into zero order, first order, Higuchi and Korsemeyer-Peppas models to identify the pharmacokinetics and mechanism of drug release. The results of the accelerated stability study of best formulation P8 for three months revealed that storage conditions were not found to have made any significant changes in final formulation F3. The release of cephalexin was prolonged for 6 h by using polymer combinations of HPMC and a twice daily matrix tablet was formulated. PMID:22523453

  17. Film-coated matrix mini-tablets for the extended release of a water-soluble drug.

    PubMed

    Mohamed, Faiezah A A; Roberts, Matthew; Seton, Linda; Ford, James L; Levina, Marina; Rajabi-Siahboomi, Ali R

    2015-04-01

    Extended release (ER) of water-soluble drugs from hydroxypropylmethylcellulose (HPMC) matrix mini-tablets (mini-matrices) is difficult to achieve due to the large surface area to volume ratio of the mini matrices. Therefore, the aims of this study were to control the release of a water-soluble drug (theophylline) from mini-matrices by applying ER ethylcellulose film coating (Surelease®), and to assess the effects of Surelease®:pore former (Opadry®) ratio and coating load on release rates. Mini-matrices containing 40%w/w HPMC K100M CR were coated with 100:0, 85:15, 80:20, 75:25 or 70:30 Surelease®:Opadry® to different coating weight gains (6-20%). Non-matrix mini-tablets were also produced and coated with 80:20 Surelease®:Opadry® to different coating weight gains. At low coating weight gains, nonmatrix mini-tablets released the entire drug within 0.5?h, while at high coating weight gains only a very small amount (<5%) of drug was released after 12?h. The gel formation of HPMC prevented disintegration of mini-matrices at low coating weight gains but contributed to rupture of the film even at high coating weight gains. As a result, drug release from mini-matrices was slower than that from nonmatrix mini-tablets at low coating weight gains, yet faster at high coating weight gains. An increase in the lag time of drug release from mini-matrices was observed as the concentration of Opadry® reduced or the coating weight gain increased. This study has demonstrated the possibility of extending the release of a water-soluble drug from HPMC mini-matrices by applying ER film coating with appropriate levels of pore former and coating weight gains to tailor the release rate. PMID:24564797

  18. Atenolol release from hydrophilic matrix tablets with hydroxypropylmethylcellulose (HPMC) mixtures as gelling agent: effects of the viscosity of the HPMC mixture

    Microsoft Academic Search

    María-Jesús Vázquez; Marta Casalderrey; Roberto Duro; José-Luis Gómez-Amoza; Ramón Martínez-Pacheco; Consuelo Souto; Angel Concheiro

    1996-01-01

    The aims of this study were to assess the potential value of hydroxypropylmethylcellulose (HPMC) mixtures as gelling agents in matrix tablets for hydrosoluble drugs, and to investigate relationships between gelling agent viscosity and the kinetics of drug release from such tablets. Experiments were carried out with MethocelR K100LV (an HPMC with nominal viscosity of 100 cP) and MethocelR K100M (an

  19. Response Surface Optimization of Sustained Release Metformin-Hydrochloride Matrix Tablets: Influence of Some Hydrophillic Polymers on the Release

    PubMed Central

    Roy, Amitava; Roy, Kalpana; Roy, Sarbani; Deb, Jyotirmoy; Ghosh, Amitava; Ali, Kazi Asraf

    2012-01-01

    The aim of the present work was designed to develop a model-sustained release matrix tablet formulation for Metformin hydrochloride using wet granulation technique. In the present study the formulation design was employed to statistically optimize different parameters of Metformin hydrochloride tablets at different drug-to-polymer ratios employing polymers Hydroxypropyl methylcellulose of two grades K4M and K100M as two independent variables whereas the dependent variables studied were X60, X120, T50, T90, n, and b values obtained from dissolution kinetics data. The in vitro drug release studies were carried out at simulated intestinal fluids, and the release showed a non-Fickian anomalous transport mechanism. The drug release was found to reveal zero order kinetics. The granules and the tablets were tested for their normal physical, morphological, and analytical parameters and were found to be within the satisfactory levels. There were no significant drug-polymer interactions as revealed by infrared spectra. It has been found out that on an optimum increased Hydroxypropyl methylcellulose K100M concentration and decreased Hydroxypropyl methylcellulose K4M concentration the formulations were elegant in terms of their release profiles and were found to be statistically significant and generable. PMID:22988527

  20. The use of response surface methodology for the formulation and optimization of salbutamol sulfate hydrophilic matrix sustained release tablets.

    PubMed

    Chaibva, Faith A; Walker, Roderick B

    2012-01-01

    The objective of this study was to develop a hydrophilic matrix formulation with in vitro release characteristics similar to Asthalin(®) tablets and that would sustain the release of salbutamol sulfate over a 12-h period. A central composite design was used as the framework for manufacturing formulations that may be used to understand the relationships between polymer levels and in vitro release characteristics. Tablets were manufactured using wet granulation with Surelease(®) as the granulating fluid and different levels of Methocel(®) K100M, xanthan gum, and Carbopol(®) 974P as matrix-forming materials. In vitro dissolution testing was conducted using USP Apparatus 3 and samples were analyzed using a validated reversed-phase HPLC method. The results revealed that the levels and types of polymers had a significant impact on the rate of drug release from these formulations and that it was possible to optimize the levels of matrix-forming polymers to achieve the desired release characteristics. Statistical design and response surface methodology have been successfully used to understand and optimize formulation factors and interactions that impact the in vitro release characteristics of salbutamol sulfate from a potential multisource sustained release dosage form. PMID:21428702

  1. The Impact of Dose and Solubility of Additives on the Release from HPMC Matrix Tablets—Identifying Critical Conditions

    Microsoft Academic Search

    Farhad Tajarobi; Susanna Abrahmsén-Alami; Magnus Hansen; Anette Larsson

    2009-01-01

    Purpose  The dissolution of HPMC matrix tablets containing different amounts of highly soluble (mannitol) or poorly soluble (dicalcium\\u000a phosphate, DCP) was studied to deduce the parameters critical to release robustness.\\u000a \\u000a \\u000a \\u000a Methods  The release of HPMC and additives was studied using a modified USP II method at two paddle stirring rates, 50 and 125 rpm,\\u000a at HPMC content varying from 15% to 100%.\\u000a \\u000a \\u000a \\u000a Results  At

  2. Near-infrared spectroscopic analysis of the breaking force of extended-release matrix tablets prepared by roller-compaction: influence of plasticizer levels and sintering temperature.

    PubMed

    Dave, Vivek S; Fahmy, Raafat M; Hoag, Stephen W

    2015-06-01

    The aim of this study was to investigate the feasibility of near-infrared (NIR) spectroscopy for the determination of the influence of sintering temperature and plasticizer levels on the breaking force of extended-release matrix tablets prepared via roller-compaction. Six formulations using theophylline as a model drug, Eudragit® RL PO or Eudragit® RS PO as a matrix former and three levels of TEC (triethyl citrate) as a plasticizer were prepared. The powder blend was roller compacted using a fixed roll-gap of 1.5?mm, feed screw speed to roller speed ratio of 5:1 and roll pressure of 4?MPa. The granules, after removing fines, were compacted into tablets on a Stokes B2 rotary tablet press at a compression force of 7?kN. The tablets were thermally treated at different temperatures (Room Temperature, 50, 75 and 100?°C) for 5?h. These tablets were scanned in reflectance mode in the wavelength range of 400-2500?nm and were evaluated for breaking force. Tablet breaking force significantly increased with increasing plasticizer levels and with increases in the sintering temperature. An increase in tablet hardness produced an upward shift (increase in absorbance) in the NIR spectra. The principle component analysis (PCA) of the spectra was able to distinguish samples with different plasticizer levels and sintering temperatures. In addition, a 9-factor partial least squares (PLS) regression model for tablets containing Eudragit® RL PO had an r(2) of 0.9797, a standard error of calibration of 0.6255 and a standard error of cross validation (SECV) of 0.7594. Similar analysis of tablets containing Eudragit® RS PO showed an r(2) of 0.9831, a standard error of calibration of 0.9711 and an SECV of 1.192. PMID:24785574

  3. Formulation and In-vitro Characterization of Sustained Release Matrix Type Ocular Timolol Maleate Mini-Tablet

    PubMed Central

    Mortazavi, Seyed Alireza; Jafariazar, Zahra; Ghadjahani, Yasaman; Mahmoodi, Hoda; Mehtarpour, Farzaneh

    2014-01-01

    The purpose of this study was preparation and evaluation of sustained release matrix type ocular mini-tablets of timolol maleate, as a potential formulation for the treatment of glaucoma. Following the initial studies on timolol maleate powder, it was formulated into ocular mini-tablets. The polymers investigated in this study included cellulose derivatives (HEC, CMC, EC) and Carbopol 971P. Mannitol was used as the solubilizing agent and magnesium stearate as the lubricant. Mini-tablets were prepared by through mixing of the ingredients, followed by direct compression. All the prepared formulations were evaluated in terms of physicochemical tests, including uniformity of weight, thickness, crushing strength, friability and in-vitro drug release. Four groups of formulations were prepared. The presence of different amounts of cellulose derivatives or Carbopol 971P, alone, was studied in group A formulations. In group B formulations, the effect of adding Carbopol 971P alongside different cellulose derivatives was investigated. Group C formulations were made by including mannitol as the solubilizing agent, alongside Carbopol 971P and a cellulose derivative. In group D formulations, mini-tablets were made using Carbopol 971P, alongside two different cellulose derivative. The selected formulation (C1) contained ethyl cellulose, Carbopol 971P, mannitol and magnesium stearate, which showed almost 100% drug release over 5 h. Based on kinetic studies, this formulation was found to best fit the zero-order model of drug release. However, the Higuchi and Hixson -Crowell models also showed a good fit. Hence, overall, formulation C1 was chosen as the best formulation. PMID:24734053

  4. Paroxetine hydrochloride controlled release POLYOX matrix tablets: screening of formulation variables using Plackett-Burman screening design.

    PubMed

    Jin, Shun-Ji; Yoo, Yeon-Hee; Kim, Min-Soo; Kim, Jeong-Soo; Park, Jeong-Sook; Hwang, Sung-Joo

    2008-03-01

    The aim of the present study was to screen the effects of the formulation variables - POLYOX molecular weight (X1), the ratio of POLYOX/Avicel PH102 (X2) and the amount of POLYOX and Avicel PH102 (X3), hardness (X4), HPMCP amount (X5), Eudragit L100 amount (X6), and citric acid amount (X7) - on the paroxetine hydrochloride release from POLYOX matrix tablet using the Plackett-Burman screening design. Paroxetine hydrochloride matrix tablets were prepared according to a 7-factor-12-run statistical model and subjected to a 8-h dissolution study in Tris buffer at pH 7.5. The regression results showed that POLYOX molecular weight (X1) and POLYOX/Avicel PH102 ratio (X2) had significantly influence on the drug release mechanism and drug release rate as main effects. Hardness (X4) had an insignificant effect on the drug release mechanism but a significant effect on the drug release rate. On the other hand, HPMCP, Eudragit L100 and citric acid had an insignificant effect on the both responses. The information obtained by screening design study can be expected to be useful for further formulation studies. PMID:18409056

  5. Formulation development and optimization of sustained release matrix tablet of Itopride HCl by response surface methodology and its evaluation of release kinetics

    PubMed Central

    Bose, Anirbandeep; Wong, Tin Wui; Singh, Navjot

    2012-01-01

    The objective of this present investigation was to develop and formulate sustained release (SR) matrix tablets of Itopride HCl, by using different polymer combinations and fillers, to optimize by Central Composite Design response surface methodology for different drug release variables and to evaluate drug release pattern of the optimized product. Sustained release matrix tablets of various combinations were prepared with cellulose-based polymers: hydroxy propyl methyl cellulose (HPMC) and polyvinyl pyrolidine (pvp) and lactose as fillers. Study of pre-compression and post-compression parameters facilitated the screening of a formulation with best characteristics that underwent here optimization study by response surface methodology (Central Composite Design). The optimized tablet was further subjected to scanning electron microscopy to reveal its release pattern. The in vitro study revealed that combining of HPMC K100M (24.65 MG) with pvp(20 mg)and use of LACTOSE as filler sustained the action more than 12 h. The developed sustained release matrix tablet of improved efficacy can perform therapeutically better than a conventional tablet. PMID:23960836

  6. Formulation development and optimization of sustained release matrix tablet of Itopride HCl by response surface methodology and its evaluation of release kinetics.

    PubMed

    Bose, Anirbandeep; Wong, Tin Wui; Singh, Navjot

    2013-04-01

    The objective of this present investigation was to develop and formulate sustained release (SR) matrix tablets of Itopride HCl, by using different polymer combinations and fillers, to optimize by Central Composite Design response surface methodology for different drug release variables and to evaluate drug release pattern of the optimized product. Sustained release matrix tablets of various combinations were prepared with cellulose-based polymers: hydroxy propyl methyl cellulose (HPMC) and polyvinyl pyrolidine (pvp) and lactose as fillers. Study of pre-compression and post-compression parameters facilitated the screening of a formulation with best characteristics that underwent here optimization study by response surface methodology (Central Composite Design). The optimized tablet was further subjected to scanning electron microscopy to reveal its release pattern. The in vitro study revealed that combining of HPMC K100M (24.65 MG) with pvp(20 mg)and use of LACTOSE as filler sustained the action more than 12 h. The developed sustained release matrix tablet of improved efficacy can perform therapeutically better than a conventional tablet. PMID:23960836

  7. A novel gastro-floating multiparticulate system for dipyridamole (DIP) based on a porous and low-density matrix core: in vitro and in vivo evaluation.

    PubMed

    Li, Zhao; Xu, Heming; Li, Shujuan; Li, Qijun; Zhang, Wenji; Ye, Tiantian; Yang, Xinggang; Pan, Weisan

    2014-01-30

    The study was aimed to develop a novel gastro-floating multiparticulate system based on a porous and low-density matrix core with excellent floatability. The gastro-floating pellets (GFP) were composed of a porous matrix core, a drug loaded layer (DIP and HPMC), a sub-coating layer (HPMC) and a retarding layer (Eudragit(®) NE 30D). The porous matrix cores were evaluated in specific. EC was chosen as the matrix membrane for its rigidity and minimal expansion to large extent. The porous matrix core was achieved by the complete release of the bulk water soluble excipient from the EC coated beads, and mannitol was selected as the optimal water soluble excipient. SEM photomicrographs confirmed the structure of porous matrix cores. The compositions of GFP were investigated and optimized by orthogonal array design. The optimized formulation could sustain the drug release for 12h and float on the dissolution medium for at least 12h without lag time to float. The pharmacokinetic study was conducted in beagle dogs, and the relative bioavailability of the test preparation was 193.11±3.43%. In conclusion, the novel gastro-floating pellets can be developed as a promising approach for the gastro-retentive drug delivery systems. PMID:24368104

  8. Alginate/cashew gum floating bead as a matrix for larvicide release.

    PubMed

    Paula, Haroldo C B; de Oliveira, Erick F; Abreu, Flávia O M S; de Paula, Regina C M

    2012-08-01

    A polymeric floating system composed of Alginate (ALG) and Cashew gum (CG), loaded with an essential oil (Lippia sidoides-Ls) was prepared by ionotropic gelation, characterized regarding its physical-chemistry properties and evaluated on its potential as a controlled release system. The influence of process parameters on the buoyancy, loading, swelling and in vitro and in vivo release kinetics, was investigated. Results showed that beads produced with carbonate and Ls at high level contents exhibit good floatability (up to 5 days) and loading capacity (15.2-23.8%). In vitro release data showed a Fickian diffusion profile and in vivo experiments showed that ALG-CG floating system presented a superior and prolonged larvicide effect, in comparison with non-floating ones, presenting larvae mortality values of 85% and 33%, respectively, after 48 h. These results indicate that ALG-CG floating beads loaded with Ls presented enhanced oil entrapment efficiency, excellent floating ability, and suitable larvicide release pattern. PMID:24364941

  9. Influence of admixed citric acid and physiological variables on the vinpocetine release from sodium alginate compressed matrix tablets.

    PubMed

    Nie, Shufang; Wu, Jie; Liu, Hui; Pan, Weisan; Liu, Yanli

    2011-08-01

    In this study, the controlled release matrix tablets of vinpocetine were prepared by direct compression using sodium alginate (SAL) as hydrophilic polymer and different amounts of citric acid as hydrosoluble acidic excipient to set up a system bringing about zero-order release of this drug in distilled water containing 0.5% sodium dodecyl sulfate. At the critical content of admixed citric acid (60 mg/tab.), the lowest drug-release rate was observed. In order to explain the effect of this critical content on drug-release rate from SAL matrices, investigation of the possibility of interaction of citric acid with SAL was performed using differential scanning calorimetric analysis and infrared analysis, which confirmed the existence of direct citric acid-SAL interaction when these two excipients came in contact with water. A zero-order drug-release system could be obtained by regulating the ratio of citric acid-to-SAL and the capacity of this system in controlling drug-release rate depended on the extent of interaction between citric acid and SAL. It is worth noticing that pH and the ionic strength of the dissolution medium were found to exert an influence on the drug-release performance of SAL tablets. PMID:21417613

  10. Investigation of the influence of mean HPMC particle size and number of polymer particles on the release of aspirin from swellable hydrophilic matrix tablets

    Microsoft Academic Search

    Paul Wan Sia Heng; Lai Wah Chan; Michael G Easterbrook; Xiaoman Li

    2001-01-01

    The effects of hydroxypropyl methylcellulose (HPMC) of different particle size ranges, size distributions and concentrations on the release behaviour of aspirin from a swellable matrix tablet system were studied. A mean HPMC (Methocel K15M Premium) particle size of 113 ?m was identified as a critical threshold in this study. Drug release rate increased markedly when polymer particle size was increased

  11. Report: in vitro dissolution studies of different brands of sustained release diclofenac sodium matrix tablet available in Bangladesh.

    PubMed

    Abdullah, M D Addnan; Bepary, Sukumar; Rouf, Abu Shara Shamsur

    2008-01-01

    Commercially available national thirteen brands and three international brands of diclofenac sodium sustained release matrix tablets were studied in simulated gastric medium (pH 1.2) for 2 hours time period and simulated intestinal medium (pH 6.8) for 10 hours time period using USP reference dissolution apparatus. All the national and international brands complied with the USP in-vitro dissolution specification for drug releases in simulated gastric medium. However, four of the national brands (Code: DS-5, DS-8, DS-12, and DS-13) failed to fulfill their official requirement of 80% drug release within 8th hour in simulated intestinal medium. Drug release of those four national brands were 78.1%, 74.9%, 72.1%, and 77.8% respectively within the specified time period, however one national brand (Code: DS-2) released 83.2% drug within 6th hour in intestinal medium. Drug release profiles were analyzed for Higuchi equation, zero order, and first order to reveal the release kinetics perspective of diclofenac sodium sustained release matrix tablets. It was found that zero order release kinetics was predominant release mechanism than first order and Higuchi release kinetics for those brands (Code: DS-1, DS-3, DS-4, DS-6, DS-7, DS-9, DS-10, DS-11, DS-X, DS-Y and DS-Z) which complied with the USP in vitro dissolution specification for drug releases. On the other hand, first order release kinetics was predominant for five national substandard formulation brands (Code: DS-2, DS-5, DS-8, DS-12 and DS-13). PMID:18166523

  12. The effect of citric acid added to hydroxypropyl methylcellulose (HPMC) matrix tablets on the release profile of vinpocetine.

    PubMed

    Nie, Shufang; Pan, Weisan; Li, Xiaodong; Wu, Xueming

    2004-07-01

    Vinpocetine is a pH-dependent experimental drug with a short half-life. The sustained-release matrix tablets of vinpocetine were prepared by direct compression using hydroxypropyl methylcellulose (HPMC) and different amounts of citric acid to set up a system bringing about gradual release of this drug. In order to investigate the influence of citric acid and the pH value of medium on the drug release from HPMC matrix tablets, an in vitro release test was carried out in either phosphate buffer pH 6.8 [0.5% sodium dodecyl sulfate (SDS)] for 12 hr or in 0.1 N HCl (0.5% SDS) (0-2 hr) and phosphate buffer pH 6.8 (0.5% SDS) (2-12 hr). Dissolution curves were described by the Peppas equation: M(t)/M(inf)=ktn, and the influence of citric acid on the dissolution mechanism was estimated according to the regression parameter-n and k values. The addition of citric acid and the pH value of medium could notably influence the dissolution behavior and mechanism of drug-release from matrices. Increasing the amounts of citric acid produced an increase in drug release rate, which showed a good linear relationship between contents of citric acid and drug accumulate release (%) in phosphate buffer pH 6.8 (0.5% SDS) (r>0.99). Moreover, a higher drug release rate could be found in 0.1 N HCl (0.5% SDS) than that in phosphate buffer pH 6.8 (0.5% SDS) during the first two hours when the content of citric acid added to matrices was lower than 45 mg/tab., but no significant difference could be found when the content of citric acid was above that value. Increasing amounts of citric acid produced decreasing values of n and increasing values of k, in a linear relationship, which indicated there was a trend favoring the mechanism of diffusion with the addition of increasing quantities of citric acid. PMID:15285336

  13. Effect of calcium ions on the gelling and drug release characteristics of xanthan matrix tablets

    Microsoft Academic Search

    Saša Baumgartner; Matej Pavli; Julijana Kristl

    2008-01-01

    Xanthan is a well-known biopolymer. It is an anionic polysaccharide, whose primary structure depends on the bacterial strain and fermentation conditions. Xanthan was extensively studied in combination with galactomannans, and over 90 patents cover the technology of this preparation. Our aim was to investigate the relation between the physical properties of a xanthan matrix in the absence or presence of

  14. Effects of coformers on phase transformation and release profiles of carbamazepine cocrystals in hydroxypropyl methylcellulose based matrix tablets.

    PubMed

    Qiu, Shi; Li, Mingzhong

    2015-02-01

    The aim of this study was to investigate the effects of coformers on phase transformation and release profiles of carbamazepine (CBZ) cocrystals in hydroxypropyl methylcellulose (HPMC) based matrix tablets. It has been found that selection of different coformers of saccharin (SAC) and cinnamic acid (CIN) can affect the stability of CBZ cocrystals in solution, resulting in significant differences in the apparent solubility of CBZ. The dissolution advantage of CBZ-SAC cocrystals can only be shown for a short period during dissolution because of the fast conversion to its dihydrate form (DH). HPMC can partially inhibit the crystallisation of CBZ DH during dissolution of CBZ-SAC cocrystal. However, the increased viscosity of HPMC dissolution medium reduced the dissolution rate of CBZ-SAC cocrystals. Therefore the CBZ-SAC cocrystal formulation did not show any significant advantage in CBZ release rate. In contrast the improved CBZ dissolution rate of CBZ-CIN cocrystal can be realised in both solution and formulation due to its high stability. In conclusion, exploring and understanding the mechanisms of the phase transformation of pharmaceutical cocrystals in aqueous medium for selection of lead cocrystals is the key for success of product development. PMID:25542989

  15. Single-dose evaluation of safety, tolerability and pharmacokinetics of newly formulated hydromorphone immediate-release and hydrophilic matrix extended-release tablets in healthy Japanese subjects without co-administration of an opioid antagonist.

    PubMed

    Toyama, Kaoru; Uchida, Naoki; Ishizuka, Hitoshi; Sambe, Takehiko; Kobayashi, Shinichi

    2015-09-01

    This single dose, open-label study investigated the safety, tolerability and pharmacokinetics of single oral doses of newly formulated immediate-release (IR) and hydrophilic matrix extended-release (ER) hydromorphone tablets in healthy Japanese subjects without co-administration of an opioid antagonist under fasting and fed conditions. Plasma and urinary concentrations of hydromorphone and metabolites were measured by liquid-chromatography tandem mass-spectroscopy. Following administration of the ER tablet, plasma concentrations of hydromorphone slowly increased with a median tmax of 5.0?h and the Cmax decreased to 37% of the IR tablet, while the AUC0-inf was comparable with that of the IR tablet when administered at the same dose. The degree of fluctuation in the plasma concentration for the ER tablet was much lower than that of the IR tablet and certain levels of plasma concentrations were maintained after 24?h of ER dosing. The AUC0-inf and Cmax increased with food for both IR and ER tablets. The AUC0-inf of hydromorphone-3-glucoside was one-tenth of that of hydromorphone-3-glucuronide. A single oral administration of the hydromorphone tablets would be well-tolerated in healthy Japanese subjects despite a lack of co-administration of an opioid antagonist and the newly developed ER hydromorphone tablets may have the appropriate PK characteristics for once-daily dosing. PMID:25807927

  16. A novel pH-responsive interpolyelectrolyte hydrogel complex for the oral delivery of levodopa. Part II: characterization and formulation of an IPEC-based tablet matrix.

    PubMed

    Ngwuluka, Ndidi C; Choonara, Yahya E; Kumar, Pradeep; du Toit, Lisa C; Khan, Riaz A; Pillay, Viness

    2015-03-01

    This study was undertaken in order to apply a synthesized interpolyelectrolyte complex (IPEC) of polymethacrylate and carboxymethylcellulose as a controlled release oral tablet matrix for the delivery of the model neuroactive drug levodopa. The IPEC (synthesized in Part I of this work) was characterized by techniques such as Fourier Transform Infra-Red (FTIR) spectroscopy, Differential Scanning Calorimetry (DSC), Advanced DSC (ADSC), and Scanning Electron Microscopy (SEM). The tablet matrices were formulated and characterized for their drug delivery properties and in vitro drug release. FTIR confirmed the interaction between the two polymers. The IPEC composite generated tablet matrices with a hardness ranging from 19.152-27.590 N/mm and a matrix resilience ranging between 42 and 46%. An IPEC of polymethacrylate and carboxymethylcellulose was indeed an improvement on the inherent properties of the native polymers providing a biomaterial with the ability to release poorly soluble drugs such as levodopa at a constant rate over a prolonged period of time. PMID:24909309

  17. The consequence of the chemical composition of HPMC in matrix tablets on the release behaviour of model drug substances having different solubility.

    PubMed

    Viridén, Anna; Wittgren, Bengt; Larsson, Anette

    2011-01-01

    This study investigates the effect of the chemical heterogeneity of hydroxypropyl methylcellulose (HPMC) on the release of model drug substances from hydrophilic matrix tablets. The hypothesis was that the release of drug substances could be influenced by possible interactions with HPMC batches having different chemical heterogeneity. The cloud point of the most heterogeneous batch was more affected by the model drug substances, methylparaben and butylparaben, and most by butylparaben with the lowest solubility. The different clouding behaviour was explained by the heterogeneously substituted batches being more associative and the more lipophilic butylparaben being able to interact more efficiently with the hydrophobic HPMC transient crosslinks that formed. Interestingly, tablet compositions of the heterogeneously substituted HPMC batches released the more soluble methylparaben at lower rates than butylparaben. The explanation is that the hydrophobic HPMC interactions with butylparaben made the gel of the tablet less hydrated and more fragile and therefore more affected by erosional stresses. In contrast, drug release from compositions consisting of the more homogeneously substituted batches was affected to a minor extent by the drugs and was very robust within the experimental variations. The present study thus reveals that there can be variability in drug release depending on the lipophilicity of the drug and the substituent heterogeneity of the HPMC used. PMID:21081160

  18. Studies on drug release kinetics from ibuprofen-carbomer hydrophilic matrix tablets: influence of co-excipients on release rate of the drug.

    PubMed

    Khan, G M; Zhu, J B

    1999-02-01

    Controlled-release (CR) matrix tablets of ibuprofen (IBF) and Carbopol(R) 934P, and blended mixture of Carbopol(R) 934P and 971P resins, at different drug to polymers ratios, were prepared by the direct compression method. The investigation focuses on the influence of the proportion of the matrix material, and several co-excipients (lactose, microcrystalline cellulose (MCC), and starch) on the mechanism and release rate of the drug from the tablets. In vitro drug release in pH 7.2 phosphate buffer solution appears to occur both by diffusion and a swelling-controlled mechanism, exhibiting either anomalous or Case II type transport. The release process could be described by plotting the fraction released versus time and fitting data to the simple exponential model: Mt/Minfinity=ktn. The release kinetics were modified when the blended mixtures of Carbopol(R) 934P and 971P resins were used as the matrix materials. In general, all of the co-excipients, used in this study, enhanced the release rate of IBF. However, lactose demonstrated slower and more linear release behavior as compared to microcrystalline cellulose or starch. The dissolution T50 and T90 values for the three co-excipients were in the order of lactose>microcrystalline cellulose>starch. PMID:9971903

  19. Eudragit(®) RS PO/RL PO as rate-controlling matrix-formers via roller compaction: Influence of formulation and process variables on functional attributes of granules and tablets.

    PubMed

    Dave, Vivek S; Fahmy, Raafat M; Bensley, Dennis; Hoag, Stephen W

    2012-10-01

    The influence of plasticizer level, roll pressure and sintering temperature was investigated on the granule properties, tablet breaking force and theophylline release from tablets. Nine formulations using theophylline as a model drug, Eudragit(®) RL PO, Eudragit(®) RS PO, or both as a matrix former and triethyl citrate (TEC) as a plasticizer were prepared. The formulations were roller compacted and the granules obtained were evaluated for particle size distribution and flowability. These granules were compacted into tablets at a compression force of 7?kN. The tablets were thermally treated at different temperatures (50 and 75°C) for 5?h and were evaluated for breaking force and dissolution. Increase in roll pressure and TEC levels resulted in a progressive increase in the mean particle size of the granules. The flowability of the granules also improved with increasing roll pressures and TEC levels. Tablet breaking force increased with an increase in TEC levels and sintering temperatures. But these effects were significant only at the highest level of plasticizer and sintering temperature respectively. For the tablets containing Eudragit(®) RS PO, theophylline release decreased proportionately with increase in TEC levels and sintering temperatures. Tablets containing either Eudragit(®) RL PO or a mixture of RS PO and RL PO failed to impart an extended-release property to the tablets at the studied variables i.e. roll pressure, TEC levels and sintering temperature. It was clearly demonstrated that with suitable optimization of these parameters, the release-rate of a water soluble drug from the matrix tablets prepared via roller compaction can be finely controlled. PMID:22257339

  20. Stomach-specific drug delivery of 5-fluorouracil using floating alginate beads.

    PubMed

    Shishu; Gupta, Neeta; Aggarwal, Nidhi

    2007-01-01

    A multiple-unit-type oral floating dosage form (FDF) of 5-fluorouracil (5-FU) was developed to prolong gastric residence time, target stomach cancer, and increase drug bioavailability. The floating bead formulations were prepared by dispersing 5-FU together with calcium carbonate into a mixture of sodium alginate and hydroxypropyl methylcellulose solution and then dripping the dispersion into an acidified solution of calcium chloride. Calcium alginate beads were formed, as alginate undergoes ionotropic gelation by calcium ions and carbon dioxide develops from the reaction of carbonate salts with acid. The evolving gas permeated through the alginate matrix, leaving gas bubbles or pores, which provided the beads buoyancy. The prepared beads were evaluated for percent drug loading, drug entrapment efficiency, image, surface topography, buoyancy, and in vitro release. The formulations were optimized for different weight ratios of gas-forming agent and sodium alginate. The beads containing higher amounts of calcium carbonate demonstrated instantaneous, complete, and excellent floating ability over a period of 24 hours. The optimized formulation was subjected to in vivo antitumor studies to check the therapeutic efficacy of the floating dosage forms containing 5-FU against benzo(a)pyrene-induced stomach tumors in albino female mice (Balb/C strain). The multiple-bead FDF was found to reduce the tumor incidence in mice by 74%, while the conventional tablet dosage form reduced this incidence by only 25%. Results indicate that FDF performed significantly better than the simple tablet dosage form. PMID:17625805

  1. The Effects of Lactose, Microcrystalline Cellulose and Dicalcium Phosphate on Swelling and Erosion of Compressed HPMC Matrix Tablets: Texture Analyzer

    PubMed Central

    Namdeo Tukaram, Bendgude; Vidaya Rajagopalan, Iyer; Sushi Ikumar Shartchandra, Poddar

    2010-01-01

    This paper reviews the use of texture analysis in studying the performance of hydrophilic matrices of highly soluble drugs and different types of excipients (i.e. water-soluble, water-insoluble and swellable, and water insoluble and non-swellable). Tablets were prepared by direct compression, and their swelling and erosion in presence of these different excipients were assessed with the help of volumetric, gravimetric, morphological, and rheological studies. Dissolution test was performed using USP 26 apparatus 2 modified by insertion of a sieve to prevent sticking of the tablets to the bottom of the vessel and allow them to swell 3-dimensionally. Loading 15% of the highly soluble drug in formulations containing 65% lactose showed the most pronounced swelling and erosion and the best sustained drug release, compared to matrices containing microcrystalline cellulose and dicalcium phosphate. The correlation between front movement, mass erosion and solute transport in relation to excipient type on progression of probe displacement and total work was examined throughout texture analysis studies. The formulation containing the soluble excipient lactose showed better swelling and erosion properties compared to formulations containing the swellable and insoluble excipients. In conclusion, it could be said that based on the distinct conventional dosage forms insertion of particular excipients in hydrophilic controlled release tablets containing water soluble drug, the finger print information of drug release profile could be obtained. To study the release profile from hydroxy propyl methyl cellulose K 15M matrices with different types of excpients, diltiazem hydrochloride was used as a model soluble drug. PMID:24381599

  2. Floating-Point Arithmetic Nicolas Brisebarre Florent de Dinechin

    E-print Network

    Muller, Jean-Michel

    - tinuous set (the real numbers) with a finite set (the "machine numbers") is not a straightforward task of a radix-60 floating-point representa- tion of w. A famous tablet from the Yale Babylonian Collection (YBC 7289) gives an approximation to 2 with four sexagesimal places (the digits represented on the tablet

  3. Accurate and Efficient Algorithms for Floating

    E-print Network

    Koev, Plamen

    i i Accurate and Efficient Algorithms for Floating Point Computation J. Demmel and P. Koev 1 expressions containing floating point numbers, and for computing matrix factorizations (like LU, the singular is challenging because our accuracy demand is much stricter than usual. The classes of floating point expressions

  4. Tablet Weaving

    ERIC Educational Resources Information Center

    Kren, Margo

    1976-01-01

    Article described a weaving technique called tablet weaving, an ancient textile process that provides opportunity for making a variety of items, such as guitar straps, belts, and decorative bands. (Author/RK)

  5. Effect of hydrophilic natural gums in formulation of oral-controlled release matrix tablets of propranolol hydrochloride.

    PubMed

    Rajesh, K S; Venkataraju, M P; Gowda, D V

    2009-04-01

    In order to develop a controlled delivery of highly water-soluble propranolol hydrochloride (PPHCl) using hydrophilic natural gums (xanthan gum [X] and locust bean gum [LBG]) as cost-effective, nontoxic, easily available. The granules of PPHCl were prepared by wet granulation method using a different ratios drug: gum ratios of X, LBG and XLBG(X and LBG in 1:1 ratios). To increase the flowability and compressibility of the granules, and to prevent its adhesion to punch and die, magnesium stearate and talc were added to the granules in 1:2 ratios before punching. The tablet was analysed to determine hardness, friability, % assay and invitro release study was carried out. The release of PPHCl from a gelatinous swollen mass, which controls the diffusion of drug molecules through the polymeric material into aqueous medium. The XLBG matrice shows precise controlled release than the X and LBG matrice because of burst effect and fast release in case of X and LBG matrice respectively and there was no chemical interaction between drug and polymer in XLBG formulation as confirmed by FTIR studies. First pass effect of PPHCl can be avoided by these formulations. Matrices with XLBG show zero-order release via swelling, diffusion and relaxation mechanism. The XLBG matrice leads to more precise result than X and LBG alone by the utilization of synergistic interaction between two biopolymers and uniformity in the hydration layer in dissolution media. However, according to the similarity factor (f(2)) XLBG3 were the most similar formulations to Lol-SR as the reference standard. PMID:19339235

  6. Computational model of matrix remodeling and entrenchment in the free-floating fibroblast-populated collagen lattice.

    PubMed

    Simon, D D; Murtada, S-I; Humphrey, J D

    2014-12-01

    Tissue equivalents represent excellent model systems for elucidating principles of mechanobiology and for exploring methods to improve the functionality of tissue-engineered constructs. The simplest tissue equivalent is the free-floating fibroblast-populated collagen lattice. Although introduced over 30?years ago, the associated mechanics of the cell-mediated compaction of this lattice was only recently analyzed in detail. The goal of this paper was to build on this recent stress analysis by developing a computational model of the evolving geometry, regionally varying material properties and cell stresses, and overall residual stress fields during the first two days of compaction. Baseline results were found to agree well with most experimental observations, namely evolving changes in radius, thickness, and material symmetry, yet hypothesis testing revealed aspects of the mechanobiology that require more experimental attention. Given the generality of the proposed framework, we submit that modifications and refinements can be used to study many similar systems and thereby help guide future experiments. PMID:25178626

  7. Effect of HPMC - E15 LV premium polymer on release profile and compression characteristics of chitosan/ pectin colon targeted mesalamine matrix tablets and in vitro study on effect of pH impact on the drug release profile.

    PubMed

    Newton, A M J; Lakshmanan, Prabakaran

    2014-04-01

    The study was designed to investigate the in vitro dissolution profile and compression characteristics of colon targeted matrix tablets prepared with HPMC E15 LV in combination with pectin and Chitosan. The matrix tablets were subjected to two dissolution models in various simulated fluids such as pH 1.2, 6, 6.8, 7.2, 5.5. The fluctuations in colonic pH conditions during IBD (inflammatory bowel disease) and the nature of less fluid content in the colon may limit the expected drug release in the polysaccharide-based matrices when used alone. The Hydrophilic hydroxyl propyl methylcellulose ether premium polymer (HPMC E15 LV) of low viscosity grade was used in the formulation design, which made an excellent modification in physical and compression characteristics of the granules. The release studies indicated that the prepared matrices could control the drug release until the dosage form reaches the colon and the addition HPMC E15 LV showed the desirable changes in the dissolution profile by its hydrophilic nature since the colon is known for its less fluid content. The hydrophilic HPMC E15 LV allowed the colonic fluids to enter into the matrix and confirmed the drug release at the target site from a poorly water soluble polymer such as Chitosan and also from water soluble Pectin. The dramatic changes occurred in the drug release profile and physicochemical characteristics of the Pectin, Chitosan matrix tablets when a premium polymer HPMC E15 LV added in the formulation design in the optimized concentration. Various drug release mechanisms used for the examination of drug release characteristics. Drug release followed the combined mechanism of diffusion, erosion, swelling and polymer entanglement. In recent decade, IBD attracts many patents in novel treatment methods by using novel drug delivery systems. PMID:24597626

  8. Overview o floating point

    E-print Network

    Biagioni, Edoardo S.

    Overview o floating point - SPARC double floats - SPARC quad floats - Intel coprocessor - Intel formats - Intel operations o processor; SPARC 64-bit Floating Point Representation o 1 bit for the sign s (0

  9. Formulation and Evaluation of Fixed-Dose Combination of Bilayer Gastroretentive Matrix Tablet Containing Atorvastatin as Fast-Release and Atenolol as Sustained-Release

    PubMed Central

    Dey, Sanjay; Chattopadhyay, Sankha; Mazumder, Bhaskar

    2014-01-01

    The objective of the present study was to develop bilayer tablets of atorvastatin and atenolol that are characterized by initial fast-release of atorvastatin in the stomach and comply with the release requirements of sustained-release of atenolol. An amorphous, solvent evaporation inclusion complex of atorvastatin with ?-cyclodextrin, present in 1?:?3 (drug/cyclodextrin) molar ratio, was employed in the fast-release layer to enhance the dissolution of atorvastatin. Xanthan gum and guar gum were integrated in the sustained-release layer. Bilayer tablets composed of sustained-release layer (10% w/w of xanthan gum and guar gum) and fast-release layer [1?:?3 (drug/cyclodextrin)] showed the desired release profile. The atorvastatin contained in the fast-release layer showed an initial fast-release of more than 60% of its drug content within 2?h, followed by sustained release of the atenolol for a period of 12?h. The pharmacokinetic study illustrated that the fast absorption and increased oral bioavailability of atorvastatin as well as therapeutic concentration of atenolol in blood were made available through adoption of formulation strategy of bilayer tablets. It can be concluded that the bilayer tablets of atorvastatin and atenolol can be successfully employed for the treatment of hypertension and hypercholesterolemia together through oral administration of single tablet. PMID:24527446

  10. Floating Boats

    ERIC Educational Resources Information Center

    Waugh, Michael

    2007-01-01

    The purpose of this article is to describe a simple laboratory activity in which students collect a series of measurements and then use graphical analysis to determine the nature of the relationship between an object's mass and the volume of water it displaces. In this activity, students explore the relationships between the mass of a floating…

  11. Ice Floats

    NSDL National Science Digital Library

    2012-08-03

    This is a lesson about displacement, buoyancy, and density. Learners will understand why ice floats. Includes background information, teacher notes, assessment criteria, and related resources; activities are differentiated for Pre-K-grade 2 and grades 3-5. This is lesson 4 of the unit Exploring Ice in the Solar System.

  12. Floating Butterfly

    NSDL National Science Digital Library

    Fresno Community Science Workshop

    2012-01-01

    In this activity, learners create a cool floating animal using the science of magnetism. Learners discover what happens when a piece of magnetic metal enters a magnet's field. Learners also examine magnetic poles. Note, a drill is required for this activity, and is not included in the cost of materials.

  13. Floating Boats

    NSDL National Science Digital Library

    Michael Waugh

    2007-07-01

    The purpose of this article is to describe a simple laboratory activity in which students collect a series of measurements and then use graphical analysis to determine the nature of the relationship between an object's mass and the volume of water it displaces. In this activity, students explore the relationships between the mass of a floating object, the amount the object sinks in the water, and its displaced volume. The data will reveal a unique relationship between an object's metrically measured mass and volume and its buoyancy in water. This can lead to an elaboration of the density concept and provide a concrete model for systems involving other forms of balance and equilibrium.

  14. Terahertz technology: a boon to tablet analysis.

    PubMed

    Wagh, M P; Sonawane, Y H; Joshi, O U

    2009-05-01

    The terahertz gap has a frequency ranges from approximately 0.3 THz to approximately 10 THz in the electromagnetic spectrum which is in between microwave and infrared. The terahertz radiations are invisible to naked eye. In comparison with x-ray they are intrinsically safe, non-destructive and non-invasive. Terahertz spectroscopy enables 3D imaging of structures and materials, and the measurement of the unique spectral fingerprints of chemical and physical forms. Terahertz radiations are produced by a dendrimer based high power terahertz source and spectroscopy technologies. It resolves many of the questions left unanswered by complementary techniques, such as optical imaging, Raman and infrared spectra. In the pharmaceutical industries it enables nondestructive, internal, chemical analysis of tablets, capsules, and other dosage forms. Tablet coatings are a major factor in drug bioavailability. Therefore tablet coatings integrity and uniformity are of crucial importance to quality. Terahertz imaging gives an unparalleled certainty about the integrity of tablet coatings and the matrix performance of tablet cores. This article demonstrates the potential of terahertz pulse imaging for the analysis of tablet coating thickness by illustrating the technique on tablets. PMID:20490288

  15. Terahertz Technology: A Boon to Tablet Analysis

    PubMed Central

    Wagh, M. P.; Sonawane, Y. H.; Joshi, O. U.

    2009-01-01

    The terahertz gap has a frequency ranges from ?0.3 THz to ?10 THz in the electromagnetic spectrum which is in between microwave and infrared. The terahertz radiations are invisible to naked eye. In comparison with x-ray they are intrinsically safe, non-destructive and non-invasive. Terahertz spectroscopy enables 3D imaging of structures and materials, and the measurement of the unique spectral fingerprints of chemical and physical forms. Terahertz radiations are produced by a dendrimer based high power terahertz source and spectroscopy technologies. It resolves many of the questions left unanswered by complementary techniques, such as optical imaging, Raman and infrared spectra. In the pharmaceutical industries it enables nondestructive, internal, chemical analysis of tablets, capsules, and other dosage forms. Tablet coatings are a major factor in drug bioavailability. Therefore tablet coatings integrity and uniformity are of crucial importance to quality. Terahertz imaging gives an unparalleled certainty about the integrity of tablet coatings and the matrix performance of tablet cores. This article demonstrates the potential of terahertz pulse imaging for the analysis of tablet coating thickness by illustrating the technique on tablets. PMID:20490288

  16. Floating portable pump

    Microsoft Academic Search

    Eberhardt

    1985-01-01

    A floating portable pump is constructed of a float defining a well for containing water, a centrifugal pump supported on the float with its impeller shaft extending vertically and with its suction inlet submerged in water in the well, and an internal combustion engine arranged to drive the pump impeller. The pump and engine are secured together on the float

  17. Preparation of a Matrix Type MultipleUnit Gastro Retentive Floating Drug Delivery System for Captopril Based on Gas Formation Technique: In Vitro Evaluation

    Microsoft Academic Search

    Lingam Meka; Bhaskar Kesavan; Krishna Mohan Chinnala; Venkateswarlu Vobalaboina; Madhusudan Rao Yamsani

    2008-01-01

    A gastro retentive floating drug delivery system with multiple-unit minitab’s based on gas formation technique was developed\\u000a in order to prolong the gastric residence time and to increase the overall bioavailability of the drug. The system consists\\u000a of the drug-containing core units prepared by direct compression process, which are coated with three successive layers of\\u000a an inner seal coat, effervescent

  18. Determining the polymer threshold amount for achieving robust drug release from HPMC and HPC matrix tablets containing a high-dose BCS class I model drug: in vitro and in vivo studies.

    PubMed

    Klan?ar, Uroš; Baumgartner, Saša; Legen, Igor; Smrdel, Polona; Kampuš, Nataša Jeraj; Krajcar, Dejan; Markun, Boštjan; Ko?evar, Klemen

    2015-04-01

    It is challenging to achieve mechanically robust drug-release profiles from hydrophilic matrices containing a high dose of a drug with good solubility. However, a mechanically robust drug release over prolonged period of time can be achieved, especially if the viscosity and amount of the polymer is sufficiently high, above the "threshold values." The goal of this research was to determine the hydroxypropyl cellulose (HPC) and hydroxypropyl methylcellulose (HPMC) polymer threshold amount that would enable robust drug release from matrix tablets containing a high dose of levetiracetam as a class I model drug according to the Biopharmaceutical Classification System (BCS). For this purpose, formulations containing HPC or HPMC of similar viscosity range, but in different amounts, were prepared. Based on the dissolution results, two final formulations were selected for additional in vitro and in vivo evaluation to confirm the robustness and to show bioequivalence. Tablets were exposed to various stress conditions in vitro with the use of different mechanically stress-inducing dissolution methods. The in vitro results were compared with in vivo results obtained from fasted and fed bioequivalence studies. Under both conditions, the formulations were bioequivalent and food had a negligible influence on the pharmacokinetic parameters C max and area under the curve (AUC). It was concluded that the drug release from both selected formulations is mechanically robust and that HPC and HPMC polymers with intrinsic viscosities above 9 dL/g and in quantities above 30% enable good mechanical resistance, which ensures bioequivalence. In addition, HPC matrices were found to be more mechanically robust compared to HPMC. PMID:25331194

  19. A Floating Controlled-Release Drug Delivery System: In Vitro-in Vivo Evaluation

    Microsoft Academic Search

    Subhash Desai; Sanford Bolton

    1993-01-01

    A novel floating controlled-release drug delivery system was formulated in an effort increase the gastric retention time of the dosage form and to control drug release. The buoyancy was attributed to air and oil entrapped in the agar gel network. A floating controlled-release 300-mg theophylline tablet having a density of 0.67 was prepared and compared in vitro and in vivo

  20. Video- Demonstration of Seltzer Tablet in Water Onboard the International Space Station (ISS)

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Saturday Morning Science, the science of opportunity series of applied experiments and demonstrations, performed aboard the International Space Station (ISS) by Expedition 6 astronaut Dr. Don Pettit, revealed some remarkable findings. In this video clip, Pettit demonstrates dropping an Alka Seltzer tablet into a film of water which becomes a floating ball of activity filled water. Watch the video to see the surprising results!

  1. Microstructural investigation of tablet compaction and tablet pharmacological properties

    E-print Network

    Mao, Kangyi

    2010-01-01

    In current tablet manufacturing processes, there is a knowledge gap concerning material transformation and the subsequent impact on tablet properties; this gap presents a barrier to rational formulation / process design. ...

  2. A new tablet brittleness index.

    PubMed

    Gong, Xingchu; Sun, Changquan Calvin

    2015-06-01

    Brittleness is one of the important material properties that influences the success or failure of powder compaction. We have discovered that the reciprocal of diametrical elastic strain at fracture is the most suitable tablet brittleness indices (TBIs) for quantifying brittleness of pharmaceutical tablets. The new strain based TBI is supported by both theoretical considerations and a systematic statistical analysis of friability data. It is sufficiently sensitive to changes in both tablet compositions and compaction parameters. For all tested materials, it correctly shows that tablet brittleness increases with increasing tablet porosity for the same powder. In addition, TBI increases with increasing content of a brittle excipient, lactose monohydrate, in the mixtures with a plastic excipient, microcrystalline cellulose. A probability map for achieving less than 1% tablet friability at various combinations of tablet tensile strength and TBI was constructed. Data from marketed tablets validate this probability map and a TBI value of 150 is recommended as the upper limit for pharmaceutical tablets. This TBI can be calculated from the data routinely obtained during tablet diametrical breaking test, which is commonly performed for assessing tablet mechanical strength. Therefore, it is ready for adoption for quantifying tablet brittleness to guide tablet formulation development since it does not require additional experimental work. PMID:25907006

  3. Does temperature increase induced by tableting contribute to tablet quality?

    Microsoft Academic Search

    K. M. Picker-Freyer; A. G. Schmidt

    2004-01-01

    The aim of this paper is to determine temperature and structural changes caused by tableting and to deduce from the combination\\u000a of temperature measurement and the determination of structural changes whether temperature increase induced by tableting contributes\\u000a to tablet quality. Tablets were produced of microcrystalline cellulose (MCC), spray-dried lactose, pregelatinized starch,\\u000a and dicalcium phosphate dihydrate (DCPD) with an instrumented single

  4. Float Zone Workshop

    NASA Technical Reports Server (NTRS)

    Naumann, R. J.

    1980-01-01

    A summary of the Analytical Float Zone Experiment System (AFZES) concept is presented. The types of experiments considered for such a facility are discussed. Reports from various industrial producers and users of float zone material are presented. Special emphasis is placed on state-of-the-art developments in low gravity manufacturing and their applications to space processing.

  5. Parade Float Construction 101

    E-print Network

    Moore, Paul A.

    be beneficial. Vehicle Selection and Getting To and From The Parade Floats can be built on a variety of beds, dangerous objects, and protruding nails. Many floats will require that you build a frame over the existing wagon. Other designs simply use the wagon bed as is and add the superstructure needed for your design

  6. Tablet Splitting: A Risky Practice

    MedlinePLUS

    ... Updates by E-mail Consumer Updates RSS Feed Tablet Splitting: A Risky Practice Search the Consumer Updates ... Pharmacists Association. This includes skipping doses and splitting tablets in an effort to save money. Regarding the ...

  7. Granule size distribution of tablets.

    PubMed

    Virtanen, Satu; Antikainen, Osmo; Räikkönen, Heikki; Yliruusi, Jouko

    2010-04-01

    The purpose of this study was to determine the variation in the granule size distribution in a die of an eccentric tableting machine. Theophylline anhydrate and alpha-lactose monohydrate were granulated with an aqueous solution of polyvinylpyrrolidone, using an instrumented fluid bed granulator. The granules were tabletted, using an instrumented eccentric tableting machine. Punch forces were recorded and tablets were collected in order during the tableting process. Powder samples, which had the same mass as the tablets, were also collected from the die for particle size determination. The particle size distribution was measured, using a spatial filtering technique. In addition, the segregation of microcrystalline cellulose pellets during tableting was analyzed. The particle size distribution changed dramatically during the tableting process, due to a segregation phenomenon. PMID:19780134

  8. Vindolanda Tablets Online

    NSDL National Science Digital Library

    Written in ink on postcard-sized sheets of wood, the Vindolanda tablets constitute a fascinating record of life in Roman Britain in the area of northern England around Hadrian's Wall during the first and second centuries AD. The tablets and the accompanying visual and printed materials were brought online through the collaborative efforts of the Centre for the Study of Ancient Documents and the Academic Computing Development Team at Oxford University. Visitors unfamiliar with the world of Roman Britain would do well to go first to the Exhibition section which contains helpful areas devoted to the world of military life during this period, the tablets themselves, and the excavations at Vindolanda. The Reference section also provides a great deal of context to the commentaries contained on the tablets, providing information about the military units in the Roman army and important dates and events in early Roman Britain. The heart of the site is dedicated to the tablets themselves, which may be browsed by number or searched by such variables as title, author, English translation, or commentary.

  9. Charge retention characteristics of silicide-induced crystallized polycrystalline silicon floating gate thin-film transistors for active matrix organic light-emitting diode.

    PubMed

    Park, Jae Hyo; Son, Se Wan; Byun, Chang Woo; Kim, Hyung Yoon; Joo, So Na; Lee, Yong Woo; Yun, Seung Jae; Joo, Seung Ki

    2013-10-01

    In this work, non-volatile memory thin-film transistor (NVM-TFT) was fabricated by nickel silicide-induced laterally crystallized (SILC) polycrystalline silicon (poly-Si) as the active layer. The nickel seed silicide-induced crystallized (SIC) poly-Si was used as storage layer which is embedded in the gate insulator. The novel unit pixel of active matrix organic light-emitting diode (AMOLED) using NVM-TFT is proposed and investigated the electrical and optical performance. The threshold voltage shift showed 17.2 V and the high reliability of retention characteristic was demonstrated until 10 years. The retention time can modulate the recharge refresh time of the unit pixel of AMOLED up to 5000 sec. PMID:24245194

  10. Development of press-coated, floating-pulsatile drug delivery of lisinopril.

    PubMed

    Jagdale, Swati C; Suryawanshi, Vishnu M; Pandya, Sudhir V; Kuchekar, Bhanudas S; Chabukswar, Aniruddha R

    2014-06-01

    Lisinopril is an angiotensin-converting enzyme (ACE) inhibitor, primarily used for the treatment of hypertension, congestive heart failure, and heart attack. It belongs to BCS class III having a half-life of 12 hrs and 25% bioavailability. The purpose of the present work was to develop a press-coated, floating-pulsatile drug delivery system. The core tablet was formulated using the super-disintegrants crosprovidone and croscarmellose sodium. A press-coated tablet (barrier layer) contained the polymer carrageenan, xanthan gum, HPMC K4M, and HPMC K15M. The buoyant layer was optimized with HPMC K100M, sodium bicarbonate, and citric acid. The tablets were evaluated for physical characteristics, floating lag time, swelling index, FTIR, DSC, and in vitro and in vivo behavior. The 5% superdisintgrant showed good results. The FTIR and DSC study predicted no chemical interactions between the drug and excipients. The formulation containing xanthan gum showed drug retaining abilities, but failed to float. The tablet containing HPMC K15M showed a high swelling index. The lag time for the tablet coated with 200 mg carrageenan was 3±0.1 hrs with 99.99±1.5% drug release; with 140 mg HPMC K4M, the lag time was 3±0.1 hrs with 99.71±1.2% drug release; and with 120 mg HPMC K15M, the lag time was 3±0.2 hrs with 99.98±1.7% drug release. The release mechanism of the tablet followed the Korsmeyer-Peppas equation and a first-order release pattern. Floating and lag time behavior have shown good in vitro and in vivo correlations. PMID:24959410

  11. Development of Press-Coated, Floating-Pulsatile Drug Delivery of Lisinopril

    PubMed Central

    Jagdale, Swati C.; Suryawanshi, Vishnu M.; Pandya, Sudhir V.; Kuchekar, Bhanudas S.; Chabukswar, Aniruddha R.

    2014-01-01

    Lisinopril is an angiotensin-converting enzyme (ACE) inhibitor, primarily used for the treatment of hypertension, congestive heart failure, and heart attack. It belongs to BCS class III having a half-life of 12 hrs and 25% bioavailability. The purpose of the present work was to develop a press-coated, floating-pulsatile drug delivery system. The core tablet was formulated using the super-disintegrants crosprovidone and croscarmellose sodium. A press-coated tablet (barrier layer) contained the polymer carrageenan, xanthan gum, HPMC K4M, and HPMC K15M. The buoyant layer was optimized with HPMC K100M, sodium bicarbonate, and citric acid. The tablets were evaluated for physical characteristics, floating lag time, swelling index, FTIR, DSC, and in vitro and in vivo behavior. The 5% superdisintgrant showed good results. The FTIR and DSC study predicted no chemical interactions between the drug and excipients. The formulation containing xanthan gum showed drug retaining abilities, but failed to float. The tablet containing HPMC K15M showed a high swelling index. The lag time for the tablet coated with 200 mg carrageenan was 3±0.1 hrs with 99.99±1.5% drug release; with 140 mg HPMC K4M, the lag time was 3±0.1 hrs with 99.71±1.2% drug release; and with 120 mg HPMC K15M, the lag time was 3±0.2 hrs with 99.98±1.7% drug release. The release mechanism of the tablet followed the Korsmeyer-Peppas equation and a first-order release pattern. Floating and lag time behavior have shown good in vitro and in vivo correlations. PMID:24959410

  12. Tablet Process Simulator

    NSDL National Science Digital Library

    The North Carolina Community College System BioNetwork's interactive eLearning tools (IETs) are reusable chunks of training that can be deployed in a variety of courses or training programs. IETs are designed to enhance, not replace hands-on training. Learners are able to enter a hands-on lab experience better prepared and more confident. This particular IET is a Tablet Process Simulator in which visitors set up and run a tablet press in a virtual 3D environment. The tool requires the program to be downloaded and installed, and gives helpful installation instructions. Users will start by downloading a zip file to their computer.

  13. Properties of sustained-release tablets prepared by hot-melt extrusion.

    PubMed

    Zhang, F; McGinity, J W

    1999-05-01

    The objectives of the present study were to investigate the properties of polyethylene oxide (PEO) as a drug carrier and to study the release mechanism of chlorpheniramine maleate (CPM) from matrix tablets prepared by hot-melt extrusion. During the hot-melt extrusion process, a dry powder blend of drug, polymer, and other adjuvants was fed into the extruder and melted inside the barrel of the machine. The molten mass was extruded through a rod-shaped die and then cut manually into 400-mg tablets. CPM and PEO were shown to be stable under the processing conditions. The molecular weight of the PEO, the drug loading percentage, and the inclusion of polyethylene glycol as a processing aid, were all found to influence the processing conditions and the drug release properties of the extruded tablets. Faster release of CPM from the matrix tablets was observed in acidic medium than in purified water and phosphate buffer (pH 7.4). Drug release from the matrix tablet was controlled by erosion of the PEO matrix and the diffusion of the drug through the swollen gel layer at the surface of the tablets. CPM was dispersed at the molecular level in the PEO matrix at low drug loading level and recrystallization of CPM was observed at high drug loading levels. Hot-melt extrusion was demonstrated to be a viable novel method to prepare sustained-release tablets. PEO was shown to be a suitable polymeric carrier for this process. PMID:10231885

  14. Micromechanisms with floating pivot

    DOEpatents

    Garcia, Ernest J. (Albuquerque, NM)

    2001-03-06

    A new class of tilting micromechanical mechanisms have been developed. These new mechanisms use floating pivot structures to relieve some of the problems encountered in the use of solid flexible pivots.

  15. The floating plank

    Microsoft Academic Search

    R. Delbourgo

    1987-01-01

    The stable floating configuration of a long plank of rectangular cross section depends on the relative density of the plank to the fluid and on the ratio of the sides. The complete solution of this metacentric problem is given.

  16. Concrete production floating platforms

    SciTech Connect

    Letourneur, O.; Falcimaigne, J.

    1981-01-01

    The floating production platforms operating in the North Sea are adapted from drilling semisubmersibles which allow only a limited payload capacity. Experience of concrete production platforms constructed for the North Sea has led Sea Tank Co. to propose a floating platform which offers large payload and oil storage capacities similar to those of existing fixed platforms. Sea Tank Co. and Institut Francais du Petrole joined forces in early 1976 to study the feasibility of a concrete floating production platform incorporating the structure and the production riser together. The results of this 3-yr program show that the concrete floating structure is economically attractive for permanent utilization on a production site. Furthermore, concrete has definite advantages over other materials, in its long term behavior.

  17. Floating Squares (GCMP)

    NSDL National Science Digital Library

    Floating Squares: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will coat a piece of notecard with graphite (from pencil lead). We then will float the piece in two beakers containing water and a second solvent. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

  18. Ketorolac tromethamine floating beads for oral application: Characterization and in vitro/in vivo evaluation.

    PubMed

    Abou El Ela, Amal El Sayeh F; Hassan, Maha A; El-Maraghy, Dalia A

    2014-09-01

    The floating beads have been employed to make a sustained release of the drug in the stomach and to decrease the dose of the drug and hence overcome its side effects. The common benefits of the floating beads were it is easy preparation, without the need of a high temperature, and high percentage of the drug entrapment. In the present work, the Ketorolac tromethamine (KT) floating beads were prepared by extrusion congealing method utilizing calcium carbonate as a gas forming agent. The physical characters of the produced beads were investigated such as KT yield, KT loading, and entrapment efficiency of the drug. In addition, floating behavior, swelling, particle size, morphology and KT stability were also evaluated. In vitro drug release study was carried out, and the kinetics of the release was evaluated using the linear regression method. Furthermore, the in vivo analgesic effect of KT after oral administration of the selected formula of floating beads (F10) was carried out using hot plate and tail flick methods. Oral commercial KT tablets and KT solution were used for the comparison. The prepared beads remained floated for more than 8 h. The optimized formulation (F10) exhibited prolonged drug release (more than 8 h) and the drug release follows the Higuchi kinetic model, with a Fickian diffusion mechanism according to Korsmeyer-Peppas (n = 0.466). Moreover, F10 showed a sustained analgesic effect as compared to the commercial tablet. PMID:25161380

  19. Ketorolac tromethamine floating beads for oral application: Characterization and in vitro/in vivo evaluation

    PubMed Central

    Abou el Ela, Amal El Sayeh F.; Hassan, Maha A.; El- Maraghy, Dalia A.

    2013-01-01

    The floating beads have been employed to make a sustained release of the drug in the stomach and to decrease the dose of the drug and hence overcome its side effects. The common benefits of the floating beads were it is easy preparation, without the need of a high temperature, and high percentage of the drug entrapment. In the present work, the Ketorolac tromethamine (KT) floating beads were prepared by extrusion congealing method utilizing calcium carbonate as a gas forming agent. The physical characters of the produced beads were investigated such as KT yield, KT loading, and entrapment efficiency of the drug. In addition, floating behavior, swelling, particle size, morphology and KT stability were also evaluated. In vitro drug release study was carried out, and the kinetics of the release was evaluated using the linear regression method. Furthermore, the in vivo analgesic effect of KT after oral administration of the selected formula of floating beads (F10) was carried out using hot plate and tail flick methods. Oral commercial KT tablets and KT solution were used for the comparison. The prepared beads remained floated for more than 8 h. The optimized formulation (F10) exhibited prolonged drug release (more than 8 h) and the drug release follows the Higuchi kinetic model, with a Fickian diffusion mechanism according to Korsmeyer-Peppas (n = 0.466). Moreover, F10 showed a sustained analgesic effect as compared to the commercial tablet. PMID:25161380

  20. 21 CFR 520.581 - Dichlorophene tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...false Dichlorophene tablets. 520.581 Section...PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.581 Dichlorophene tablets. (a) Specifications... Single dose of 1 tablet (1 gram of dichlorophene...Limitations. Withhold solid foods and milk for...

  1. 21 CFR 520.581 - Dichlorophene tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...false Dichlorophene tablets. 520.581 Section...PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.581 Dichlorophene tablets. (a) Specifications... Single dose of 1 tablet (1 gram of dichlorophene...Limitations. Withhold solid foods and milk for...

  2. 21 CFR 520.1380 - Methocarbamol tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Methocarbamol tablets. 520.1380 Section 520.1380 ...ANIMAL DRUGS § 520.1380 Methocarbamol tablets. (a) Chemical name. 3-(O-Methoxyphenoxy...1-carbamate. (b) Specifications. Each tablet contains 500 milligrams of...

  3. 21 CFR 520.455 - Clomipramine tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Clomipramine tablets. 520.455 Section 520.455 Food and...NEW ANIMAL DRUGS § 520.455 Clomipramine tablets. (a) Specifications. Each tablet contains 5, 20, 40, or 80 milligrams...

  4. 21 CFR 520.1900 - Primidone tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Primidone tablets. 520.1900 Section 520.1900 Food and...NEW ANIMAL DRUGS § 520.1900 Primidone tablets. (a) Specifications. Each tablet contains 50 or 250 milligrams of...

  5. 21 CFR 520.1900 - Primidone tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Primidone tablets. 520.1900 Section 520.1900 Food and...NEW ANIMAL DRUGS § 520.1900 Primidone tablets. (a) Specifications. Each tablet contains 50 or 250 milligrams of...

  6. 21 CFR 520.2088 - Roxarsone tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Roxarsone tablets. 520.2088 Section 520.2088 Food...NEW ANIMAL DRUGS § 520.2088 Roxarsone tablets. (a)(1) Specifications. Each tablet contains 36 milligrams of roxarsone...

  7. 21 CFR 520.1380 - Methocarbamol tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Methocarbamol tablets. 520.1380 Section 520.1380 ...ANIMAL DRUGS § 520.1380 Methocarbamol tablets. (a) Chemical name. 3-(O-Methoxyphenoxy...1-carbamate. (b) Specifications. Each tablet contains 500 milligrams of...

  8. 21 CFR 520.455 - Clomipramine tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Clomipramine tablets. 520.455 Section 520.455 Food and...NEW ANIMAL DRUGS § 520.455 Clomipramine tablets. (a) Specifications. Each tablet contains 5, 20, 40, or 80 milligrams...

  9. 21 CFR 520.2088 - Roxarsone tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Roxarsone tablets. 520.2088 Section 520.2088 Food...NEW ANIMAL DRUGS § 520.2088 Roxarsone tablets. (a)(1) Specifications. Each tablet contains 36 milligrams of roxarsone...

  10. Tabletability Modulation Through Surface Engineering.

    PubMed

    Osei-Yeboah, Frederick; Sun, Changquan Calvin

    2015-08-01

    Poor powder tabletability is a common problem that challenges the successful development of high-quality tablet products. Using noncompressible microcrystalline cellulose beads, we demonstrate that surface coating is an effective strategy for modulating tabletability, almost at will, through judicious selection of coating material. This strategy has broad applicability as tabletability of such particles is dictated by the properties of the outermost layer coat regardless the nature of the core. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:2645-2648, 2015. PMID:26059496

  11. Surfactants modify the release from tablets made of hydrophobically modified poly (acrylic acid)?

    PubMed Central

    Knöös, Patrik; Onder, Sebla; Pedersen, Lina; Piculell, Lennart; Ulvenlund, Stefan; Wahlgren, Marie

    2013-01-01

    Many novel pharmaceutically active substances are characterized by a high hydrophobicity and a low water solubility, which present challenges for their delivery as drugs. Tablets made from cross-linked hydrophobically modified poly (acrylic acid) (CLHMPAA), commercially available as Pemulen™, have previously shown promising abilities to control the release of hydrophobic model substances. This study further investigates the possibility to use CLHMPAA in tablet formulations using ibuprofen as a model substance. Furthermore, surfactants were added to the dissolution medium in order to simulate the presence of bile salts in the intestine. The release of ibuprofen is strongly affected by the presence of surfactant and/or buffer in the dissolution medium, which affect both the behaviour of CLHMPAA and the swelling of the gel layer that surrounds the disintegrating tablets. Two mechanisms of tablet disintegration were observed under shear, namely conventional dissolution of a soluble tablet matrix and erosion of swollen insoluble gel particles from the tablet. The effects of surfactant in the surrounding medium can be circumvented by addition of surfactant to the tablet. With added surfactant, tablets that may be insusceptible to the differences in bile salt level between fasted or fed states have been produced, thus addressing a central problem in controlled delivery of hydrophobic drugs. In other words CLHMPAA is a potential candidate to be used in tablet formulations for controlled release with poorly soluble drugs. PMID:25755999

  12. The floating water bridge The floating water bridge

    E-print Network

    Podgornik, Rudolf

    The floating water bridge The floating water bridge Elmar C. Fuchs1 , Jakob Woisetschläger2 , Karl ____________________________________________ Abstract When high voltage is applied to distilled water filled into two glass beakers which are in contact, a stable water connection forms spontaneously, giving the impression of a floating water bridge. A detailed

  13. Can flexibility help you float?

    E-print Network

    Burton, Lisa Janelle

    We consider the role of flexibility in the weight-bearing characteristics of bodies floating at an interface. Specifically, we develop a theoretical model for a two-dimensional thin floating plate that yields the maximum ...

  14. New insights into segregation during tabletting.

    PubMed

    Lakio, S; Siiriä, S; Räikkönen, H; Airaksinen, S; Närvänen, T; Antikainen, O; Yliruusi, J

    2010-09-15

    The aim of this study was to evaluate how different granule size distributions affect the tablet compression process. The emphasis was on developing new analytic methods for compression data for entire batch. In all, 18 batches of granules containing theophylline and lactose were tabletted, using an instrumented eccentric tabletting machine. During tablet compression, upper and lower punch forces were recorded. Mathematical methods were developed for analysing the compression data during tabletting. The results suggested two types of undulation in the tabletting data: (1) short-time scale variation or tablet-to-tablet changes in force data and (2) long-time scale undulation describing the changes occurring throughout the tabletting process, such as segregation. These undulation phenomena were analysed, using various mathematical methods. In addition the results suggest that smaller particles have better tabletting properties, to a certain limit. However particle size alone cannot explain the tabletability of granules. PMID:20600718

  15. Tablet PCs: The Write Approach

    ERIC Educational Resources Information Center

    Milner, Jacob

    2006-01-01

    This article discusses the transforming effects of tablet PCs in the classroom. As 1-to-1 computing becomes the goal on K-12 campuses, school districts are turning to this newer, pen-based technology. Saint Mary's School's new Lenovo ThinkPad X41 tablet PCs had transformed the way Saint Mary's teachers did their jobs. Teachers created outlines for…

  16. Compound floating pivot micromechanisms

    DOEpatents

    Garcia, Ernest J. (Albuquerque, NM)

    2001-04-24

    A new class of tilting micromechanical mechanisms have been developed. These new mechanisms use compound floating pivot structures to attain far greater tilt angles than are practical using other micromechanical techniques. The new mechanisms are also capable of bi-directional tilt about multiple axes.

  17. Floating Paper Clip

    NSDL National Science Digital Library

    WGBH Boston

    2002-01-01

    In this activity, challenge learners to float a paper clip in a cup of water. Learners discover that a paper clip will sink in a cup of water, except when it is placed on a piece of paper towel. Use this activity to demonstrate the principles of surface tension, adhesion/cohesion, and gravity.

  18. Corona from floating electrodes

    Microsoft Academic Search

    Francisco Roman; Vernon Cooray; Viktor Scuka

    1996-01-01

    It is not unusual to have insulated conducting objects located close to the conductors of a Lightning Protection System. However, the separation of these objects from the Lightning Protection System could vary from a few millimetres to some centimetres. When the system is exposed to thunderstorm electric fields, discharge could be initiated between the Lightning Protection System and the floating

  19. Floating In Air

    NSDL National Science Digital Library

    2014-05-28

    Float a ping-pong ball with a hairdryer, as a demonstration of Bernoulli's principle. This classic physics activity includes a twist with the addition of a toilet paper tube that allows learners to explore air pressure in a different way.

  20. Tablet disintegration studied by high-resolution real-time magnetic resonance imaging.

    PubMed

    Quodbach, Julian; Moussavi, Amir; Tammer, Roland; Frahm, Jens; Kleinebudde, Peter

    2014-01-01

    The present work employs recent advances in high-resolution real-time magnetic resonance imaging (MRI) to investigate the disintegration process of tablets containing disintegrants. A temporal resolution of 75 ms and a spatial resolution of 80 × 80 µm with a section thickness of only 600 µm were achieved. The histograms of MRI videos were quantitatively analyzed with MATLAB. The mechanisms of action of six commercially available disintegrants, the influence of relative tablet density, and the impact of disintegrant concentration were examined. Crospovidone seems to be the only disintegrant acting by a shape memory effect, whereas the others mainly swell. A higher relative density of tablets containing croscarmellose sodium leads to a more even distribution of water within the tablet matrix but hardly impacts the disintegration kinetics. Increasing the polacrilin potassium disintegrant concentration leads to a quicker and more thorough disintegration process. Real-time MRI emerges as valuable tool to visualize and investigate the process of tablet disintegration. PMID:24475490

  1. Implementation of Jacobi rotations for accurate singular value computation in floating point arithmetic

    Microsoft Academic Search

    Zlatko Drmac

    1997-01-01

    In this paper the author considers how to compute the singular value decomposition (SVD) A = UΣV{sup Ï} of A = [aâ, aâ] â R{sup mx2} accurately in floating point arithmetic. It is shown how to compute the Jacobi rotation V (the right singular vector matrix) and how to compute AV = UΣ even if the floating point representation of

  2. Mucoadhesive bilayered tablets for buccal sustained release of flurbiprofen.

    PubMed

    Perioli, Luana; Ambrogi, Valeria; Giovagnoli, Stefano; Ricci, Maurizio; Blasi, Paolo; Rossi, Carlo

    2007-01-01

    The aim of this work was the design of sustained-release mucoadhesive bilayered tablets, using mixtures of mucoadhesive polymers and an inorganic matrix (hydrotalcite), for the topical administration of flurbiprofen in the oral cavity. The first layer, responsible for the tablet retention on the mucosa, was prepared by compression of a cellulose derivative and polyacrylic derivative blend. The second layer, responsible for buccal drug delivery, was obtained by compression of a mixture of the same (first layer) mucoadhesive polymers and hydrotalcite containing flurbiprofen. Nonmedicated tablets were evaluated in terms of swelling, mucosal adhesion, and organoleptic characteristics; in vitro and in vivo release studies of flurbiprofen-loaded tablets were performed as well. The best results were obtained from the tablets containing 20 mg of flurbiprofen, which allowed a good anti-inflammatory sustained release in the buccal cavity for 12 hours, ensuring efficacious salivary concentrations, and led to no irritation. This mucoadhesive formulation offers many advantages over buccal lozenges because it allows for reduction in daily administrations and daily drug dosage and is suitable for the treatment of irritation, pain, and discomfort associated with gingivitis, sore throats, laryngopharyngitis, cold, and periodontal surgery. Moreover, it adheres well to the gum and is simple to apply, which means that patient compliance is improved. PMID:17915804

  3. Poisoning with delayed-release tablets

    PubMed Central

    Meadow, S. R.; Leeson, Gerald A.

    1974-01-01

    Accidental poisoning with delayed-release tablets causes symptoms at a time when the tablets can no longer be retrieved from the stomach. A child died from eating 23 tablets of Debendox, which is a delayed-release tablet containing dicyclomine and doxylamine. A second child survived a similar overdose, having been subjected to vigorous purgation and peritoneal dialysis. PMID:4830120

  4. Pore size distribution in tablets measured with a morphological sieve.

    PubMed

    Wu, Yu San; van Vliet, Lucas J; Frijlink, Henderik W; van der Voort Maarschalk, Kees

    2007-09-01

    Porosity and pore structure are important characteristics of tablets, since they influence mechanical strength and many other properties. This paper proposes an alternative method for the characterization of pore structure based on image analysis of SEM micrographs. SEM images were made of sodium chloride tablets made with three different particle sizes. The pore size distribution in these images was determined with a technique referred to as a morphological sieve. The results were compared to the pore size distributions as obtained with mercury porosimetry. The SEM images display small cracks inside the grains and small 'floating' grains inside the pore space. As these artifacts are induced in sample preparation, they need to be identified and removed from the images before analysis. The influence of the size of the discarded structures on the total porosity and the pore size distribution was investigated. The small 'floating' grains prevented the determination of the size of large pores, but had a negligible effect on the porosity. The removal of small cracks inside the grains had no effect on the pore size distribution but a large effect on the porosity. Based on the comparison of these results with the experimentally determined porosity, a maximum size for the structures that were to be removed was determined. The resulting pore size distributions were in the same order of magnitude as the results obtained with mercury porosimetry. Both methods display a comparable relative shift of the pore size distributions to larger sizes for tablets with increasing particle size. Therefore, it can be concluded this image analysis technique is a good method for the characterization of pore structure. PMID:17580106

  5. 21 CFR 520.1200 - Ivermectin, fenbendazole, and praziquantel tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...Ivermectin, fenbendazole, and praziquantel tablets. 520.1200 Section 520.1200 Food...Ivermectin, fenbendazole, and praziquantel tablets. (a) Specifications . Each chewable tablet contains either: (1) 68...

  6. 21 CFR 520.1200 - Ivermectin, fenbendazole, and praziquantel tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Ivermectin, fenbendazole, and praziquantel tablets. 520.1200 Section 520.1200 Food...Ivermectin, fenbendazole, and praziquantel tablets. (a) Specifications . Each chewable tablet contains either: (1) 68...

  7. Effect of drug particle size in ultrasound compacted tablets. Continuum percolation model approach.

    PubMed

    Millán, Mónica; Caraballo, Isidoro

    2006-03-01

    The main objective of this work is to study the influence of the drug particle size on the pharmaceutical availability of ultrasound compacted tablets. Inert matrix systems containing different drug particle sizes were prepared using both, an ultrasound-assisted press and a traditional eccentric machine. Potassium chloride was used as drug model and Eudragit RS-PM as matrix forming excipient. The excipient particle size was kept constant. The cross-sectional microphotographs of ultrasound tablets show the existence of a quasi-continuum medium. Keeping constant the drug load, US-tablets showed very similar release rates, whereas for traditional tablets, an increase in the particle size resulted in a clear decrease in the release rate. In these tablets, the excipient forms an almost continuum medium. In an infinite theoretical system of these characteristics, the size of the drug particles will not modify the percolation threshold. The percolation of the excipient in this system can be assimilated to a continuum percolation model. In accordance with the proposed model, a lower influence of the drug particle size on the drug release rate was obtained for the US-tablets in comparison with traditional tablets. This fact can be indicative of the similarity of the drug percolation thresholds in these systems. PMID:16431046

  8. Bioadhesive Mini-Tablets for Vaginal Drug Delivery

    PubMed Central

    Hiorth, Marianne; Nilsen, Susanne; Tho, Ingunn

    2014-01-01

    Different non-ionic cellulose ethers (methyl cellulose, MC; hydroxyethyl cellulose, HEC; hydroxypropyl cellulose, HPC; hydroxypropylmethyl cellulose, HPMC) and microcrystalline cellulose (MCC) were investigated as matrix formers for preparation of mini-tablets targeting vaginal drug delivery. Hexyl aminolevulinat hydrochloridum (HAL) was used as a model drug. The mini-tablets were characterized with respect to their mechanical strength, bioadhesion towards cow vaginal tissue in two independent tests (rotating cylinder test, detachment test using texture analyzer), and dissolution rate in two media mimicking the pH levels of fertile, healthy and post-menopausal women (vaginal fluid simulant pH 4.5, phosphate buffer pH 6.8). Mini-tablets with a matrix of either HPMC or HPC were found to possess adequate mechanical strength, superior bioadhesive behavior towards vaginal tissue, and pH independent controlled release of the model drug, suggesting that both systems would be suited for the treatment of women regardless of age, i.e., respective of their vaginal pH levels. Bioadhesive mini-tablets offer a potential for improved residence time in the vaginal cavity targeting contact with mucosal tissue and prolonged release of the drug. PMID:25166286

  9. Applications of poly(ethylene oxide) in controlled release tablet systems: a review.

    PubMed

    Ma, Lulu; Deng, Li; Chen, Jianming

    2014-07-01

    To improve therapeutic effects and compatibility of patients, controlled release tablet systems based on polymers are of great interest for pharmaceutical technologies. Poly(ethylene oxide) (PEO) is a non-ionic linear hydrophilic and uncrosslinked polymer available in a number of molecular weights. It is synthesized by ethylene oxide and has many desirable properties for drug delivery applications. This review article aims to summary the recent developments on physicochemical properties of PEO and focus on the recent efforts and developments on PEO as oral controlled release matrix tablets, bioadhesive hydrophilic matrices and osmotic pump tablets. Commercial products employed PEO were also discussed. PMID:24001212

  10. Serial floating point formatter

    SciTech Connect

    Peterson, R. D.; Penner, W. A.

    1985-11-12

    A floating point formatter for changing fixed point serial digital data, such as that received by a seismic data acquisition system, is disclosed wherein fixed point serial digital data is received and scaled to remove any bias added by preamplification. The scaled data is shifted a predetermined number of bits and a resulting exponent is calculated. The shifted data signal and corresponding exponent are combined and further scaled to permit stacking the data without exceeding the system capacity.

  11. Hidden force floating ice

    E-print Network

    Chang Q. Sun

    2015-01-17

    Because of the segmental specific-heat disparity of the hydrogen bond (O:H-O) and the Coulomb repulsion between oxygen ions, cooling elongates the O:H-O bond at freezing by stretching its containing angle and shortening the H-O bond with an association of larger O:H elongation, which makes ice less dense than water, allowing it to float.

  12. WindFloat: A floating foundation for offshore wind turbines

    Microsoft Academic Search

    Dominique Roddier; Christian Cermelli; Alexia Aubault; Alla Weinstein

    2010-01-01

    This manuscript summarizes the feasibility study conducted for the WindFloat technology. The WindFloat is a three-legged floating foundation for multimegawatt offshore wind turbines. It is designed to accommodate a wind turbine, 5 MW or larger, on one of the columns of the hull with minimal modifications to the nacelle and rotor. Potential redesign of the tower and of the turbine

  13. The Disintegration Process in Microcrystalline Cellulose Based Tablets I.: Influence of Temperature, Porosity and Superdisintegrants

    E-print Network

    Yassin, Samy; Goodwin, Daniel J.; Anderson, Andrew; Sibik, Juraj; Wilson, D. Ian; Gladden, Lynn F.; Zeitler, J. Axel

    2015-06-12

    the Quality Target Product Profile. Immediate release formulations typically employ hydrophilic and hygroscopic excipients that facilitate disintegration by promoting media ingress and swelling of the tablet. Disintegrants are obviously important components... 3 cup. The sample chamber was pressurised to 10 bar with helium and this was repeated thirty times, after which a density reading for the solid matrix was recorded (solid density Dp). Using these data the density of the void space within the tablet...

  14. DENORMAL NUMBERS IN FLOATING POINT SIGNAL PROCESSING APPLICATIONS Denormal numbers in floating point signal

    E-print Network

    Mascarenhas, Walter Figueiredo

    DENORMAL NUMBERS IN FLOATING POINT SIGNAL PROCESSING APPLICATIONS Denormal numbers in floating Signal Processing, CPU Copyright 2002-2005 ­ Laurent de Soras Page 1/10 #12;DENORMAL NUMBERS IN FLOATING.............................................................................................................. 2 1. FLOATING POINT NUMBER CODING OVERVIEW...................................................... 3 1

  15. Automatic Generation of Floating-Point Test Data

    Microsoft Academic Search

    Webb Miller; David L. Spooner

    1976-01-01

    For numerical programs, or more generally for programs with floating-point data, it may be that large savings of time and storage are made possible by using numerical maximization methods instead of symbolic execution to generate test data. Two examples, a matrix factorization subroutine and a sorting method, illustrate the types of data generation problems that can be successfully treated with

  16. 21 CFR 520.1284 - Sodium liothyronine tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Sodium liothyronine tablets. 520.1284 Section 520.1284 Food...DRUGS § 520.1284 Sodium liothyronine tablets. (a) Specifications. Sodium liothyronine tablets consist of tablets intended for oral...

  17. 21 CFR 520.82a - Aminopropazine fumarate tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Aminopropazine fumarate tablets. 520.82a Section 520.82a Food...DRUGS § 520.82a Aminopropazine fumarate tablets. (a) Specifications. The drug is in tablet form. Each tablet contains...

  18. 21 CFR 520.1284 - Sodium liothyronine tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Sodium liothyronine tablets. 520.1284 Section 520.1284 Food...DRUGS § 520.1284 Sodium liothyronine tablets. (a) Specifications. Sodium liothyronine tablets consist of tablets intended for oral...

  19. 21 CFR 520.82a - Aminopropazine fumarate tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Aminopropazine fumarate tablets. 520.82a Section 520.82a Food...DRUGS § 520.82a Aminopropazine fumarate tablets. (a) Specifications. The drug is in tablet form. Each tablet contains...

  20. Genetics Home Reference: Floating-Harbor syndrome

    MedlinePLUS

    ... PubMed Recent literature OMIM Genetic disorder catalog Conditions > Floating-Harbor syndrome On this page: Description Genetic changes ... names Glossary definitions Reviewed December 2012 What is Floating-Harbor syndrome? Floating-Harbor syndrome is a disorder ...

  1. Floating JMaRT

    E-print Network

    Guillaume Bossard; Stefanos Katmadas

    2015-05-30

    We define a new partially solvable system of equations that parametrises solutions to six-dimensional N=(1,0) ungauged supergravity coupled to tensor multiplets. We obtain this system by applying a series of dualities on the known floating brane system, imposing that it allows for the JMaRT solution. We construct an explicit multi-centre solution generalising the JMaRT solution, with an arbitrary number of additional BPS centres on a line. We describe explicitly the embedding of the JMaRT solution in this system in five dimensions.

  2. Floating JMaRT

    E-print Network

    Bossard, Guillaume

    2014-01-01

    We define a new partially solvable system of equations that parametrises solutions to six-dimensional N=(1,0) ungauged supergravity coupled to tensor multiplets. We obtain this system by applying a series of dualities on the known floating brane system, imposing that it allows for the JMaRT solution. We construct an explicit multi-centre solution generalising the JMaRT solution, with an arbitrary number of additional BPS centres on a line. We describe explicitly the embedding of the JMaRT solution in this system in five dimensions.

  3. Will It Float?

    NSDL National Science Digital Library

    Jeff Major

    2006-01-01

    Student preconceptions are one of the greatest challenges we face as science teachers. This Predict, Explain, Observe, and Explain (PEOE) activity challenges students? preconceived notions about why matter floats or sinks when placed in a liquid. The idea behind this model is to do a demonstration that first confirms student's conceptions followed by a second, similar demonstration that provides discrepant information creating cognitive dissonance. Learning happens as students are forced to modify their conceptions so that their view of how things work is not in conflict with what they are seeing.

  4. Floating JMaRT

    NASA Astrophysics Data System (ADS)

    Bossard, Guillaume; Katmadas, Stefanos

    2015-04-01

    We define a new partially solvable system of equations that parametrises solutions to six-dimensional ungauged supergravity coupled to tensor multiplets. We obtain this system by applying a series of dualities on the known floating brane system, imposing that it allows for the JMaRT solution. We construct an explicit multi-centre solution generalising the JMaRT solution, with an arbitrary number of additional BPS centres on a line. We describe explicitly the embedding of the JMaRT solution in this system in five dimensions.

  5. Mirage of Floating Exchange Rates

    Microsoft Academic Search

    Carmen M. Reinhart

    2000-01-01

    This note summarizes some of the highlights of my longer paper with Guillermo Calvo”Fear of Floating.” Many emerging market countries have suffered financial crises. One view blames soft pegs for these crises. Adherents to that view suggest that countries move to corner solutions--hard pegs or floating exchange rates. We analyze the behavior of exchange rates, reserves, and interest rates to

  6. Floating offshore structure

    SciTech Connect

    Oshima, M.; Narita, H.; Tabuchi, H.; Yashima, N.

    1985-05-28

    A floating offshore structure which is moored at a fixed position on the sea by means of mooring hawsers and anchors connected to the ends thereof respectively for conducting a submarine excavating operation from a deck of the structure. The structure includes a moorage hull part provided with a vertical through-hole formed therein for receiving an excavating drill pipe and the mooring hawsers and a movable hull part connected to the moorage hull part so as to be rotatable within a horizontal plane. The movable hull part is constituted as a hull defining the outer wall of the floating offshore structure and connected with the moorage hull part by inserting it into a moorage hull part receiving hole formed at a position closer to the bow thereof. The movable hull part has near its water plane a horizontal section with a substantially oval shape formed by a fore draft part in a substantially circular or polygonal shape, with the moorage hull part receiving hole as a center and an after draft part taperingly projecting aft from the fore draft part.

  7. Modeling inter- and intra-tablet coating variability of pan coated tablets

    Microsoft Academic Search

    Arjun Vivek Kalbag

    2009-01-01

    This thesis work is focused on the modeling of inter- and intra-tablet coating variability of pan coated tablets. Tablets are coated for a number of reasons such as controlling the bioavailability and release profile of the drug (functional coatings), ensuring product identification and aesthetics, masking odor and taste and protecting the tablet core. Due to the critical nature of functional

  8. Development and in vitro characterization of mebendazole delayed release tablet for colonic drug delivery.

    PubMed

    Baviskar, Dheeraj; Rajput, Amarjit; Bare, Kapil; Biranwar, Yogeshkumar; Chaudhari, Hiralal; Narkhede, Deepak; Jain, Dinesh

    2014-03-01

    The main objective behind this study was to formulate delayed release colon targeted tablet of Mebendazole by using different polymers. The precompressional parameters of powder blend were studied. The wet granulation method was used for the preparation of tablets. The tablets of all formulation were subjected for different physicochemical evaluation. The drug-excipient interaction study was carried out by using Fourier transforms Infrared spectroscopy (FTIR). The in vitro evaluation was carried out at different pH ranges (0.1M HCl, 6.8 and 7.4 Phosphate buffer) for the prepared tablets. From the stability, Fourier transform infra-red spectroscopy studies Mebendazole tablet does not show any interaction between drug and polymer. The prepared tablets were complied all the physicochemical test as per official limit. The formulated (M3) batch shows better sustained release 99.89% over a period of 12 hours and the data was fitted into Korsemeyer-Peppas kinetic equation. The result indicates that Mebendazole colon targeted matrix tablet remain stable in the stomach and shows better release into the colon with the help of pH dependent synthetic polymers. PMID:24577910

  9. E-Books and the Tablet PC.

    ERIC Educational Resources Information Center

    Goodwin-Jones, Bob

    2003-01-01

    Highlights the emerging technologies of e-books, electronic versions of texts, and the Tablet PC, a new hybrid laptop computer and personal digital assistant that features a writing tablet and stylus-based input/navigation. (Author/VWL)

  10. 21 CFR 520.312 - Carnidazole tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Conditions of use —(1) Amount. Adult pigeons: 1 tablet (10 milligrams); newly weaned pigeons: 1/2 tablet (5 milligrams). (2...trichomoniasis (canker) in ornamental and homing pigeons. (3) Limitations. Not for...

  11. 21 CFR 520.312 - Carnidazole tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...Conditions of use —(1) Amount. Adult pigeons: 1 tablet (10 milligrams); newly weaned pigeons: 1/2 tablet (5 milligrams). (2...trichomoniasis (canker) in ornamental and homing pigeons. (3) Limitations. Not for...

  12. Oral sustained release tablets of zidovudine using binary blends of natural and synthetic polymers.

    PubMed

    Emeje, Martins; Olaleye, Olajide; Isimi, Christiana; Fortunak, Joseph; Byrn, Stephen; Kunle, Olobayo; Ofoefule, Sabinus

    2010-01-01

    Oral sustained release matrix tablets of zidovudine (ZDV) were prepared using different types, proportions and blends of carbopol 71G (C71) and a plant gum obtained from Abelmoschus esculentus (AEG). The effect of various formulation factors like polymer proportion, polymer type and pH of the dissolution medium on the in vitro release of the drug was studied, using the half change technique, in 900 ml of dissolution medium, at 100 rpm. Release kinetics were analyzed using Zero-order, Higuchi's square-root and Ritger-Peppas' empirical equations. In vitro release performance as revealed by the time taken for 70% of the drug to be released (t70%), showed that the release rate decreased with increase in polymer proportion. Matrix tablets containing 10 and 20% AEG were found to exhibit immediate-release characteristics. Matrix tablets containing 30% AEG showed t70% value of 204 min and extended the release up to 5 h, while matrix tablets containing 30% carbopol showed t70% value of 234 min and extended the release up to 6 h. Three blends of AEG and C71 at the ratio of 1:2, 2:1 and 1:3 showed t70% values of 132, 312 and 102 min respectively and extended the release up to 8 h. Mathematical analysis of the release kinetics indicated that the nature of drug release from the matrix tablets followed Fickian and anomalous release. Drug release from matrix tablets of zidovudine containing blends of AEG and C71 demonstrates the advantage of blending a natural and synthetic polymer over single polymer use. PMID:20823575

  13. Floating treatment wetlands for domestic wastewater treatment.

    PubMed

    Faulwetter, J L; Burr, M D; Cunningham, A B; Stewart, F M; Camper, A K; Stein, O R

    2011-01-01

    Floating islands are a form of treatment wetland characterized by a mat of synthetic matrix at the water surface into which macrophytes can be planted and through which water passes. We evaluated two matrix materials for treating domestic wastewater, recycled plastic and recycled carpet fibers, for chemical oxygen demand (COD) and nitrogen removal. These materials were compared to pea gravel or open water (control). Experiments were conducted in laboratory scale columns fed with synthetic wastewater containing COD, organic and inorganic nitrogen, and mineral salts. Columns were unplanted, naturally inoculated, and operated in batch mode with continuous recirculation and aeration. COD was efficiently removed in all systems examined (>90% removal). Ammonia was efficiently removed by nitrification. Removal of total dissolved N was ?50% by day 28, by which time most remaining nitrogen was present as NO(3)-N. Complete removal of NO(3)-N by denitrification was accomplished by dosing columns with molasses. Microbial communities of interest were visualized with denaturing gradient gel electrophoresis (DGGE) by targeting specific functional genes. Shifts in the denitrifying community were observed post-molasses addition, when nitrate levels decreased. The conditioning time for reliable nitrification was determined to be approximately three months. These results suggest that floating treatment wetlands are a viable alternative for domestic wastewater treatment. PMID:22105133

  14. 21 CFR 520.531 - Cythioate tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Cythioate tablets. 520.531 Section 520.531 Food...ANIMAL DRUGS § 520.531 Cythioate tablets. (a) [Reserved] (b) Sponsors...for use of 30- and 90-milligram (mg) tablets and see No. 053501 in §...

  15. Principles of Tablet Computing for Educators

    ERIC Educational Resources Information Center

    Katzan, Harry, Jr.

    2015-01-01

    In the study of modern technology for the 21st century, one of the most popular subjects is tablet computing. Tablet computers are now used in business, government, education, and the personal lives of practically everyone--at least, it seems that way. As of October 2013, Apple has sold 170 million iPads. The success of tablets is enormous and has…

  16. 21 CFR 520.804 - Enalapril tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Enalapril tablets. 520.804 Section 520.804 Food and...FORM NEW ANIMAL DRUGS § 520.804 Enalapril tablets. (a) Specifications . Each tablet contains either 1.0, 2.5, 5.0,...

  17. Scaffolding Equals Success in Teaching Tablet PCs

    ERIC Educational Resources Information Center

    Dickerson, Jeremy; Williams, Scott; Browning, J. B.

    2009-01-01

    After many years of using the mouse and keyboard as the primary means of computer input, people are seeing a strong surge into a new generation of input technologies such as tablet PCs. As more professionals adopt tablet PCs for use in the workplace, there is a subsequent increased demand for tablet PC instruction in the classroom. Examples of…

  18. 21 CFR 520.1616 - Orbifloxacin tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Orbifloxacin tablets. 520.1616 Section 520.1616 Food and...NEW ANIMAL DRUGS § 520.1616 Orbifloxacin tablets. (a) Specifications . Each tablet contains 5.7, 22.7, or 68...

  19. 21 CFR 520.531 - Cythioate tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Cythioate tablets. 520.531 Section 520.531 Food...ANIMAL DRUGS § 520.531 Cythioate tablets. (a) [Reserved] (b) Sponsors...for use of 30- and 90-milligram (mg) tablets and see No. 053501 in §...

  20. 21 CFR 520.812 - Enrofloxacin tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Enrofloxacin tablets. 520.812 Section 520.812 Food and...NEW ANIMAL DRUGS § 520.812 Enrofloxacin tablets. (a) Specifications. Each tablet contains either 22.7, 68.0, or...

  1. 21 CFR 520.1510 - Nitenpyram tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Nitenpyram tablets. 520.1510 Section 520.1510 Food and...NEW ANIMAL DRUGS § 520.1510 Nitenpyram tablets. (a) Specifications . Each tablet contains 11.4 or 57 milligrams (mg)...

  2. 21 CFR 520.812 - Enrofloxacin tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Enrofloxacin tablets. 520.812 Section 520.812 Food and...NEW ANIMAL DRUGS § 520.812 Enrofloxacin tablets. (a) Specifications. Each tablet contains either 22.7, 68.0, or...

  3. 21 CFR 520.1510 - Nitenpyram tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Nitenpyram tablets. 520.1510 Section 520.1510 Food and...NEW ANIMAL DRUGS § 520.1510 Nitenpyram tablets. (a) Specifications . Each tablet contains 11.4 or 57 milligrams (mg)...

  4. Mathematics Instruction and the Tablet PC

    ERIC Educational Resources Information Center

    Fister, K. Renee; McCarthy, Maeve L.

    2008-01-01

    The use of tablet PCs in teaching is a relatively new phenomenon. A cross between a notebook computer and a personal digital assistant (PDA), the tablet PC has all of the features of a notebook with the additional capability that the screen can also be used for input. Tablet PCs are usually equipped with a stylus that allows the user to write on…

  5. Proportion: a tablet app for collaborative learning

    Microsoft Academic Search

    Jochen Rick

    2012-01-01

    Everyday computing technology is transitioning from PCs to more natural user interfaces. At the forefront of this trend are multi-touch tablets. Each year, tablets become more affordable, capable and widespread. Now is the time for research to shape how they will be used to support learning. In this paper, I introduce the Proportion tablet application as both a concrete vision

  6. TEACHING WITH TABLET PC'S Kenrick Mock

    E-print Network

    Mock, Kenrick

    powerful desktop machines. An "official" Tablet PC, as designated by Microsoft, is essentially an x86-based or recognized as text. As a Windows XP machine, the Tablet PC has the benefit that it can directly execute anyTEACHING WITH TABLET PC'S Kenrick Mock University of Alaska Anchorage Anchorage, AK 99508 kenrick

  7. Floating Cities, Islands and States

    E-print Network

    Alexander Bolonkin

    2008-04-04

    Many small countries are in need of additional territory. They build landfills and expensive artificial islands. The ocean covers 71 per cent of the Earth surface. Those countries (or persons of wealth) starting the early colonization of the ocean may obtain advantages through additional territory or creating their own independent state. An old idea is building a big ship. The best solution to this problem, however, is the provision of floating cities, islands, and states. The author idea is to use for floating cities, islands, and states a cheap floating platform created from a natural ice field taken from the Arctic or Antarctic oceans. These cheap platforms protected by air-film (bottom and sides) and a conventional insulating cover (top) and having a cooling system can exist for an unlimited time. They can be increased in number or size at any time, float in warm oceans, travel to different continents and countries, serve as artificial airports, harbors and other marine improvements, as well as floating cities and industrial bases for virtually any use. Author researches and computes parameters of these ice floating platforms, other methods of building such floating territory, compares them and shows that the offered method is the most cheap and efficient means of ocean colonization.

  8. Tablet Analysis Using Gravimetric Dilutions

    NASA Astrophysics Data System (ADS)

    Simonson, Larry A.

    2001-10-01

    This experiment introduces the concept of gravimetric dilutions in the context of tablet analysis. Caffeine tablets are analyzed by absorbance at 274 nm with reference to a standard calibration graph and tested for compliance with the USP criterion. All samples and standards are prepared using gravimetric dilutions without reference to volume or density. This experiment is appropriate for high school and college freshman chemistry courses and may be useful at higher levels. It is only necessary that students have had exposure to Beer's law.

  9. Profiling floating point value ranges for reconfigurable

    E-print Network

    Kelly, Paul H. J.

    Profiling floating point value ranges for reconfigurable implementation Ashley W Brown, Paul H J of floating-point arithmetic. This paper presents FloatWatch, a dynamic execution profiling tool designed to identify where an application can benefit from reduced precision or re- duced range in floating

  10. Tamm floating electron in nanodiamond

    E-print Network

    Ivan A. Denisov; Peter I. Belobrov

    2011-11-12

    Nanodiamond exhibits unpaired electrons in magnetization, EPR, NMR and Auger relaxation. Wave functions and eigenenergies of a bound electron in a nanodiamond crystal have been calculated. It has been proved by using quantum mechanical analysis that unpaired electrons are self-condition of a nanodiamond as a limited crystal according to Tamm theory of surface states. The surface electron floating over a nanodiamond gives paramagnetic response and stabilizes the nanoparticle at small range of size. Possibly the spin of the floating electron can be used for floating point calculation in future quantum computers on the base of nanodiamond qubits.

  11. Floating--Point Fused Multiply--Add: Reduced Latency for Floating-Point Addition

    E-print Network

    California at Davis, University of

    Floating--Point Fused Multiply--Add: Reduced Latency for Floating-Point Addition Javier D for the computation of the double--precision floating--point multiply--add fused (MAF) operation A + (B Ã? C) that permits to compute the floating--point addition with lower latency than floating--point multiplication

  12. Floating orbital molecular dynamics simulations.

    PubMed

    Perlt, Eva; Brüssel, Marc; Kirchner, Barbara

    2014-04-21

    We introduce an alternative ab initio molecular dynamics simulation as a unification of Hartree-Fock molecular dynamics and the floating orbital approach. The general scheme of the floating orbital molecular dynamics method is presented. Moreover, a simple but sophisticated guess for the orbital centers is provided to reduce the number of electronic structure optimization steps at each molecular dynamics step. The conservation of total energy and angular momentum is investigated in order to validate the floating orbital molecular dynamics approach with and without application of the initial guess. Finally, a water monomer and a water dimer are simulated, and the influence of the orbital floating on certain properties like the dipole moment is investigated. PMID:24600690

  13. Time(24-hr) Gangion Floats

    E-print Network

    Gangion Floats Type* Type* Weights Type* Monitored Hooks / section Total sections Deployed Retrieved in comments #12;Bait Light devices Species 0 None 3 Glow bead kg 1 4 Other 2 Battery light Y / N Y / N Other

  14. NULL Convention Floating Point Multiplier

    PubMed Central

    Ramachandran, Seshasayanan

    2015-01-01

    Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to perform floating point multiplication. The proposed multiplier offers substantial decrease in power consumption when compared with its synchronous version. Performance attributes of the NULL convention logic floating point multiplier, obtained from Xilinx simulation and Cadence, are compared with its equivalent synchronous implementation. PMID:25879069

  15. Optimization Studies on Compression Coated Floating-Pulsatile Drug Delivery of Bisoprolol

    PubMed Central

    Jagdale, Swati C.; Bari, Nilesh A.; Kuchekar, Bhanudas S.; Chabukswar, Aniruddha R.

    2013-01-01

    The purpose of the present work was to design and optimize compression coated floating pulsatile drug delivery systems of bisoprolol. Floating pulsatile concept was applied to increase the gastric residence of the dosage form having lag phase followed by a burst release. The prepared system consisted of two parts: a core tablet containing the active ingredient and an erodible outer shell with gas generating agent. The rapid release core tablet (RRCT) was prepared by using superdisintegrants with active ingredient. Press coating of optimized RRCT was done by polymer. A 32 full factorial design was used for optimization. The amount of Polyox WSR205 and Polyox WSR N12K was selected as independent variables. Lag period, drug release, and swelling index were selected as dependent variables. Floating pulsatile release formulation (FPRT) F13 at level 0 (55?mg) for Polyox WSR205 and level +1 (65?mg) for Polyox WSR N12K showed lag time of 4?h with >90% drug release. The data were statistically analyzed using ANOVA, and P < 0.05 was statistically significant. Release kinetics of the optimized formulation best fitted the zero order model. In vivo study confirms burst effect at 4?h in indicating the optimization of the dosage form. PMID:24367788

  16. Floating wind turbine system

    NASA Technical Reports Server (NTRS)

    Viterna, Larry A. (Inventor)

    2009-01-01

    A floating wind turbine system with a tower structure that includes at least one stability arm extending therefrom and that is anchored to the sea floor with a rotatable position retention device that facilitates deep water installations. Variable buoyancy for the wind turbine system is provided by buoyancy chambers that are integral to the tower itself as well as the stability arm. Pumps are included for adjusting the buoyancy as an aid in system transport, installation, repair and removal. The wind turbine rotor is located downwind of the tower structure to allow the wind turbine to follow the wind direction without an active yaw drive system. The support tower and stability arm structure is designed to balance tension in the tether with buoyancy, gravity and wind forces in such a way that the top of the support tower leans downwind, providing a large clearance between the support tower and the rotor blade tips. This large clearance facilitates the use of articulated rotor hubs to reduced damaging structural dynamic loads. Major components of the turbine can be assembled at the shore and transported to an offshore installation site.

  17. Skylab floating ice experiment

    NASA Technical Reports Server (NTRS)

    Campbell, W. J. (principal investigator); Ramseier, R. O.; Weaver, R. J.; Weeks, W. F.

    1975-01-01

    The author has identified the following significant results. Coupling of the aircraft data with the ground truth observations proved to be highly successful with interesting results being obtained with IR and SLAR passive microwave techniques, and standard photography. Of particular interest were the results of the PMIS system which operated at 10.69 GHz with both vertical and horizontal polarizations. This was the first time that dual polarized images were obtained from floating ice. In both sea and lake ice, it was possible to distinguish a wide variety of thin ice types because of their large differences in brightness temperatures. It was found that the higher brightness temperature was invariably obtained in the vertically polarized mode, and as the age of the ice increases the brightness temperature increases in both polarizations. Associated with this change in age, the difference in temperature was observed as the different polarizations decreased. It appears that the horizontally polarized data is the most sensitive to variations in ice type for both fresh water and sea ice. The study also showed the great amount of information on ice surface roughness and deformation patterns that can be obtained from X-band SLAR observations.

  18. Understanding and Predicting Drug Delivery from Hydrophilic Matrix

    E-print Network

    Peppas, Nicholas A.

    , using hy- droxypropyl methylcellulose (HPMC) grades with different average molecular weights as matrix tablet; diffusion; swelling; release mechanism; modeling; hydroxypropyl methylcellulose (HPMC delivery systems is hy- droxypropyl methylcellulose (HPMC) (1). One of its most important characteristics

  19. Raman spectroscopic measurement of tablet-to-tablet coating variability.

    PubMed

    Romero-Torres, Saly; Pérez-Ramos, José D; Morris, Kenneth R; Grant, Edward R

    2005-06-15

    We report new results suggesting the feasibility of Raman spectrometry as a tool by which to examine the variability of tablet coatings. Our experiments feature a probe that can operate with a revolving laser focus to average content and coating non-uniformity. Raman spectral changes are correlated with tablet exposure times in a pan coater by means of partial least squares (PLS) multivariate analysis. Statistical models are found to be improved by pre-processing schemes that emphasize spectral changes while minimizing the effects of background light scattering and fluorescence. These pre-processing techniques include multiplicative scatter correction (MSC) and standard normal variate (SNV) transformation, used in concert with Savitzky-Golay second derivative smoothing (SGSD). The two approaches give comparable results yielding R2 values for PLS calibration and cross-calibrated prediction variance regression of 0.999 and 0.997, respectively. Correlation results and model residual values demonstrate that Raman spectroscopy serves sensitively to reflect the coating thickness of the tablets studied. PMID:15925218

  20. Fresh look at floating shock fitting

    NASA Technical Reports Server (NTRS)

    Hartwich, PETER-M.

    1990-01-01

    A fast implicit upwind procedure for the two-dimensional Euler equations is described that allows accurate computations of shocked flows on nonadapted meshes. Away from shocks, the second-order accurate upwinding is based on the split-coefficient-matrix (SCM) method. In the presence of shocks, the difference stencils are modified using a floating shock fitting technique. Rapid convergence to steady-state solutions is attained with a diagonalized approximate factorization (AF) algorithm. Results are presented for Riemann's problem, for a regular shock reflection at an inviscid wall, for supersonic flow past a cylinder, and for a transonic airfoil. All computed shocks are ideally sharp and in excellent agreement with other numerical results or 'exact' solutions. Most importantly, this has been accomplished on unusually crude meshes without any attempt to align grid lines with shock fronts or to cluster grid lines around shocks.

  1. 21 CFR 520.2041 - Pyrantel pamoate chewable tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Pyrantel pamoate chewable tablets. 520.2041 Section 520.2041 Food and...DRUGS § 520.2041 Pyrantel pamoate chewable tablets. (a) Specifications. Each tablet contains pyrantel pamoate equivalent to...

  2. 21 CFR 520.2123a - Spectinomycin tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Spectinomycin tablets. 520.2123a Section 520.2123a Food...ANIMAL DRUGS § 520.2123a Spectinomycin tablets. (a) Specifications . Each tablet contains spectinomycin dihydrochloride...

  3. 21 CFR 520.1331 - Meclofenamic acid tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2011-04-01 false Meclofenamic acid tablets. 520.1331 Section 520.1331 Food and...ANIMAL DRUGS § 520.1331 Meclofenamic acid tablets. (a) Specifications. Each tablet contains either 10 or 20 milligrams of...

  4. 21 CFR 520.1242e - Levamisole hydrochloride effervescent tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...false Levamisole hydrochloride effervescent tablets. 520.1242e Section 520.1242e Food...1242e Levamisole hydrochloride effervescent tablets. (a) Specifications. Each tablet contains 907 milligrams of levamisole...

  5. 21 CFR 520.1331 - Meclofenamic acid tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 false Meclofenamic acid tablets. 520.1331 Section 520.1331 Food and...ANIMAL DRUGS § 520.1331 Meclofenamic acid tablets. (a) Specifications. Each tablet contains either 10 or 20 milligrams of...

  6. 21 CFR 520.784 - Doxylamine succinate tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Doxylamine succinate tablets. 520.784 Section 520.784 Food...DRUGS § 520.784 Doxylamine succinate tablets. (a) Specifications. The drug is in tablet form and contains doxylamine succinate...

  7. 21 CFR 520.1341 - Megestrol acetate tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2011-04-01 false Megestrol acetate tablets. 520.1341 Section 520.1341 Food and...ANIMAL DRUGS § 520.1341 Megestrol acetate tablets. (a) Specifications. Each tablet contains 5 or 20 milligrams of megestrol...

  8. 21 CFR 520.1720a - Phenylbutazone tablets and boluses.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2011-04-01 false Phenylbutazone tablets and boluses. 520.1720a Section 520...ANIMAL DRUGS § 520.1720a Phenylbutazone tablets and boluses. (a) Specifications . Each tablet contains 100, 200, or 400...

  9. 21 CFR 520.2041 - Pyrantel pamoate chewable tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Pyrantel pamoate chewable tablets. 520.2041 Section 520.2041 Food and...DRUGS § 520.2041 Pyrantel pamoate chewable tablets. (a) Specifications. Each tablet contains pyrantel pamoate equivalent to...

  10. 21 CFR 520.1720a - Phenylbutazone tablets and boluses.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 false Phenylbutazone tablets and boluses. 520.1720a Section 520...ANIMAL DRUGS § 520.1720a Phenylbutazone tablets and boluses. (a) Specifications . Each tablet contains 100, 200, or 400...

  11. 21 CFR 520.863 - Ethylisobutrazine hydrochloride tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Ethylisobutrazine hydrochloride tablets. 520.863 Section 520.863 Food and...520.863 Ethylisobutrazine hydrochloride tablets. (a) Specifications. Each tablet contains either 10 milligrams or 50...

  12. 21 CFR 520.784 - Doxylamine succinate tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Doxylamine succinate tablets. 520.784 Section 520.784 Food...DRUGS § 520.784 Doxylamine succinate tablets. (a) Specifications. The drug is in tablet form and contains doxylamine succinate...

  13. 21 CFR 520.2582 - Triflupromazine hydrochloride tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Triflupromazine hydrochloride tablets. 520.2582 Section 520.2582 Food and...520.2582 Triflupromazine hydrochloride tablets. (a) Specifications. Each tablet contains either 10 milligrams or 25...

  14. 21 CFR 520.863 - Ethylisobutrazine hydrochloride tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Ethylisobutrazine hydrochloride tablets. 520.863 Section 520.863 Food and...520.863 Ethylisobutrazine hydrochloride tablets. (a) Specifications. Each tablet contains either 10 milligrams or 50...

  15. 21 CFR 520.623 - Diethylcarbamazine citrate, oxibendazole chewable tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Diethylcarbamazine citrate, oxibendazole chewable tablets. 520.623 Section 520.623 Food and...Diethylcarbamazine citrate, oxibendazole chewable tablets. (a) Specifications. Each tablet contains either 60, 120, or 180...

  16. 21 CFR 520.246 - Butorphanol tartrate tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Butorphanol tartrate tablets. 520.246 Section 520.246 Food and...ANIMAL DRUGS § 520.246 Butorphanol tartrate tablets. (a) Specifications. Each tablet contains 1, 5, or 10 milligrams of...

  17. 21 CFR 520.623 - Diethylcarbamazine citrate, oxibendazole chewable tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...Diethylcarbamazine citrate, oxibendazole chewable tablets. 520.623 Section 520.623 Food and...Diethylcarbamazine citrate, oxibendazole chewable tablets. (a) Specifications. Each tablet contains either 60, 120, or 180...

  18. 21 CFR 520.2123a - Spectinomycin tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Spectinomycin tablets. 520.2123a Section 520.2123a Food...ANIMAL DRUGS § 520.2123a Spectinomycin tablets. (a) Specifications . Each tablet contains spectinomycin dihydrochloride...

  19. 21 CFR 520.1446 - Milbemcyin oxime and lufenuron tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Milbemcyin oxime and lufenuron tablets. 520.1446 Section 520.1446 Food...520.1446 Milbemcyin oxime and lufenuron tablets. (a) Specifications —(1) Tablets containing: 2.3 milligrams (mg)...

  20. 21 CFR 520.1341 - Megestrol acetate tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 false Megestrol acetate tablets. 520.1341 Section 520.1341 Food and...ANIMAL DRUGS § 520.1341 Megestrol acetate tablets. (a) Specifications. Each tablet contains 5 or 20 milligrams of megestrol...

  1. 21 CFR 520.1446 - Milbemcyin oxime and lufenuron tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Milbemcyin oxime and lufenuron tablets. 520.1446 Section 520.1446 Food...520.1446 Milbemcyin oxime and lufenuron tablets. (a) Specifications —(1) Tablets containing: 2.3 milligrams (mg)...

  2. 21 CFR 520.2582 - Triflupromazine hydrochloride tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Triflupromazine hydrochloride tablets. 520.2582 Section 520.2582 Food and...520.2582 Triflupromazine hydrochloride tablets. (a) Specifications. Each tablet contains either 10 milligrams or 25...

  3. Onsite Wastewater Treatment Systems: Tablet Chlorination

    E-print Network

    Lesikar, Bruce J.

    2008-10-23

    Secondary treatment system Pump tank Tablet chlorinator Onsite wastewater treatment systems Tablet chlorination L-5344 9-08 Figure 1: The most common form of disinfection for onsite systems is tablet chlorination. W astewater that is sprayed onto... lawns must first be disinfected to prevent odors and remove disease-causing microorganisms. Wastewater can be disinfected with chlorine, ozone, and ultraviolet light. For onsite wastewater treatment systems, the most common form of disin- fection...

  4. Tablet Content Analysis Using Terahertz Transmission Spectroscopy

    Microsoft Academic Search

    John A. Spencer; Everett H. Jefferson; Ajaz S. Hussain; David Newnham; Thomas Lo

    2007-01-01

    A group of pressed tablets with acetaminophen content between 60 mg and 120 mg were scanned in the terahertz spectral region\\u000a (2 cm?1–120 cm?1) in transmission mode. Tablet acetaminophen content was determined by a standard HPLC method. Despite the lack of discernible\\u000a spectral features and the tablets being opaque above 45 cm?1, a working partial least squares model could be constructed. The results show the

  5. Design and characterization of controlled release tablet of metoprolol

    PubMed Central

    Singhvi, Gautam; Ukawala, Ravi; Dhoot, Harish; Jain, Suresh

    2012-01-01

    Metoprolol succinate is a selective beta-adrenergic receptor blocker useful in treatment of hypertension, angina and heart failure. The purpose of the present work was to design and evaluate controlled release matrix type tablet of Metoprolo succinate using HPMC K15M and Eudragit (RLPO and RSPO) as a matrix forming agents. Effect of various polymer alone and combinations were studied in pH 1.2 buffer using USP type II paddle at 50 rpm. HPMC was used to form firm gel with Eudragit polymer. Formulation with Equal proportion (1:1) of Eudragit RSPO and RLPO showed optimum drug release t50=7 hrs and t100=16 hrs indicate optimum permeability for drug release from matrix. The drug release mechanism was predominantly found to be Non-Fickian diffusion controlled. PMID:23066222

  6. Design and characterization of controlled release tablet of metoprolol.

    PubMed

    Singhvi, Gautam; Ukawala, Ravi; Dhoot, Harish; Jain, Suresh

    2012-03-01

    Metoprolol succinate is a selective beta-adrenergic receptor blocker useful in treatment of hypertension, angina and heart failure. The purpose of the present work was to design and evaluate controlled release matrix type tablet of Metoprolo succinate using HPMC K15M and Eudragit (RLPO and RSPO) as a matrix forming agents. Effect of various polymer alone and combinations were studied in pH 1.2 buffer using USP type II paddle at 50 rpm. HPMC was used to form firm gel with Eudragit polymer. Formulation with Equal proportion (1:1) of Eudragit RSPO and RLPO showed optimum drug release t(50)=7 hrs and t(100)=16 hrs indicate optimum permeability for drug release from matrix. The drug release mechanism was predominantly found to be Non-Fickian diffusion controlled. PMID:23066222

  7. 14 CFR 29.757 - Hull and auxiliary float strength.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Hull and auxiliary float strength. 29.757 Section 29... Floats and Hulls § 29.757 Hull and auxiliary float strength. The hull, and auxiliary floats if used, must withstand the...

  8. LATEX-Paragraphs Floating around Figures Thomas Kneser

    E-print Network

    LATEX-Paragraphs Floating around Figures Thomas `float' in paragraphs. T* *his article presents the LATEX style option FLOATFIG which can be used with paragraphs floating around them. For such obje* *cts Th. Reid has chosen the term `Floating Figures

  9. Detection of Floating Inputs in Logic Circuits

    NASA Technical Reports Server (NTRS)

    Cash, B.; Thornton, M. G.

    1984-01-01

    Simple modification of oscilloscope probe allows easy detection of floating inputs or tristate outputs in digital-IC's. Oscilloscope probe easily modified with 1/4 W resistor and switch for detecting floating inputs in CMOS logic circuits.

  10. Flexible dynamics of floating wind turbines

    E-print Network

    Luypaert, Thomas (Thomas J.)

    2012-01-01

    This work presents Tower Flex, a structural dynamics model for a coupled analysis of offshore floating wind turbines consisting of a tower, a floating platform and a mooring system. In this multi-body, linear frequency-domain ...

  11. CS61C Fall 2011 Floating Point and CALL -Notes modified from Fall 2010 Floating Point

    E-print Network

    California at Irvine, University of

    CS61C Fall 2011 Floating Point and CALL - Notes modified from Fall 2010 Floating Point /* 100 thousand */ #define INCREMENT .00003f /* 3 hundred thousandths */ int main(void) { int i; float x = 0.f; for (i = 0; i float result = (x - 3.f)/3.f; printf

  12. 40 CFR 65.45 - External floating roof converted into an internal floating roof.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false External floating roof converted into an internal floating roof. 65.45 Section 65.45 Protection...RULE Storage Vessels § 65.45 External floating roof converted into an internal floating...

  13. 40 CFR 65.45 - External floating roof converted into an internal floating roof.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false External floating roof converted into an internal floating roof. 65.45 Section 65.45 Protection...RULE Storage Vessels § 65.45 External floating roof converted into an internal floating...

  14. 40 CFR 65.45 - External floating roof converted into an internal floating roof.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false External floating roof converted into an internal floating roof. 65.45 Section 65.45 Protection...RULE Storage Vessels § 65.45 External floating roof converted into an internal floating...

  15. 40 CFR 65.45 - External floating roof converted into an internal floating roof.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false External floating roof converted into an internal floating roof. 65.45 Section 65.45 Protection...RULE Storage Vessels § 65.45 External floating roof converted into an internal floating...

  16. 40 CFR 65.45 - External floating roof converted into an internal floating roof.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false External floating roof converted into an internal floating roof. 65.45 Section 65.45 Protection...RULE Storage Vessels § 65.45 External floating roof converted into an internal floating...

  17. Why Do Countries Float the Way They Float?

    Microsoft Academic Search

    Ricardo Hausmann; Ugo G. Panizza; Ernesto Hugo Stein

    2000-01-01

    Countries that are classified as having floating exchange rate systems (or very wide bands) show strikingly different patterns of behavior. They hold very different levels of international reserves and allow very different volatilities in the movements of the exchange rate relative to the volatility that they tolerate either on the level of reserves or in interest rates. We document these

  18. Why do countries float the way they float?

    Microsoft Academic Search

    Ricardo Hausmann; Ugo Panizza; Ernesto Stein

    2001-01-01

    Countries that are classified as having floating exchange rate systems (or very wide bands) show strikingly different patterns of behavior. They hold very different levels of international reserves and allow very different volatilities to the movements of the exchange rate relative to the volatility that they tolerate either on the level of reserves or on interest rates. We document these

  19. Absorption of effervescent paracetamol tablets relative to ordinary paracetamol tablets in healthy volunteers

    Microsoft Academic Search

    T. Rygnestad; K. Zahlsen; F. A. Samdal

    2000-01-01

    Objectives: The aim of this study was to compare the rate of absorption between ordinary paracetamol tablets and effervescent paracetamol\\u000a tablets.\\u000a \\u000a \\u000a \\u000a Methods: Twenty healthy volunteers participated in an open randomised crossover study and were given a 1000-mg dose of either ordinary\\u000a paracetamol tablets (2??500?mg Panodil tablets, SmithKline Beecham) or effervescent paracetamol tablets (2??500?mg Pinex\\u000a Brusetablett, Alpharma AS) with a 3-week

  20. Offloading Floating Car Data Razvan Stanica

    E-print Network

    Fiore, Marco

    Offloading Floating Car Data Razvan Stanica Universit´e de Lyon, INRIA UrbaNet INSA-Lyon, CITI Lab Malandrino DET Politecnico di Torino malandrino@tlc.polito.it Abstract--Floating Car Data (FCD) is currently network by up to 95%. I. INTRODUCTION Floating Car Data (FCD) consist of information generated by moving

  1. 32 CFR 935.165 - Floating objects.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Floating objects. 935.165 Section 935...CODE Public Safety § 935.165 Floating objects. No person may anchor, moor, or beach any boat, barge, or other floating object on Wake Island in any location...

  2. Floating Point Representation Michael L. Overton

    E-print Network

    Stein, William

    Floating Point Representation Michael L. Overton copyright c fl1996 1 Computer Representation of Numbers Computers which work with real arithmetic use a system called floating point. Suppose a real : : :) 2 : To store a number in floating point representation, a computer word is divided into 3 fields

  3. 32 CFR 935.165 - Floating objects.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Floating objects. 935.165 Section 935...CODE Public Safety § 935.165 Floating objects. No person may anchor, moor, or beach any boat, barge, or other floating object on Wake Island in any location...

  4. 32 CFR 935.165 - Floating objects.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Floating objects. 935.165 Section 935...CODE Public Safety § 935.165 Floating objects. No person may anchor, moor, or beach any boat, barge, or other floating object on Wake Island in any location...

  5. 32 CFR 935.165 - Floating objects.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Floating objects. 935.165 Section 935...CODE Public Safety § 935.165 Floating objects. No person may anchor, moor, or beach any boat, barge, or other floating object on Wake Island in any location...

  6. 32 CFR 935.165 - Floating objects.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Floating objects. 935.165 Section 935...CODE Public Safety § 935.165 Floating objects. No person may anchor, moor, or beach any boat, barge, or other floating object on Wake Island in any location...

  7. Time(24-hr) Hooks Branchline Floats

    E-print Network

    (m) Seabird Mitigation HaulDir. Begin . End . Begin . F End . R Hooks Branchline Floats Type* # Float line Type* Measured length Weight (g) Shark line on floats? Hook type* Total set *relate to Types described Other explain in comments #12;Bait Light devices Species 0 None 3 Glow bead kg 1 4 Other Hook No. 2

  8. New Directions in Floating-Point Arithmetic

    NASA Astrophysics Data System (ADS)

    Beebe, Nelson H. F.

    2007-12-01

    This article briefly describes the history of floating-point arithmetic, the development and features of IEEE standards for such arithmetic, desirable features of new implementations of floating-point hardware, and discusses work-in-progress aimed at making decimal floating-point arithmetic widely available across many architectures, operating systems, and programming languages.

  9. Flinking: Neither Floating nor Sinking.

    ERIC Educational Resources Information Center

    Wilson, Roger B.

    1993-01-01

    Describes an activity that challenges students to make an object that, when released under water, does not float up or sink down. The main concept this activity investigates is the density of ordinary objects in comparison to the density of water. (PR)

  10. Floating Ring-Groove Lapper

    NASA Technical Reports Server (NTRS)

    Williams, Robert L., Sr.; Williams, Robert L., Jr.; Chase, Timothy L.

    1992-01-01

    Tool fits out-of-round seal groove and laps it to fine finish without binding. Includes floating lapping pieces riding freely in groove, and are curved to match nominal diameter of groove. One lapping piece tightened so it does not move relative to disk.

  11. The Floating Siphon - an Effective

    Microsoft Academic Search

    Alexander Kolchinski

    1997-01-01

    A simple device, which can be used in place of a syringe pump, has been suggested for high dilution experiments. The flasks containing the solutions to be mixed are equipped with siphons and placed on the top of a styrofoam cylinder, or other floater. The styrofoam cylinder floats in a beaker containing water. A glass rod is threaded through a

  12. Integrated floating point signal processor

    Microsoft Academic Search

    K. Bottcher; A. Lacroix; M. Talmi; D. Wesseling

    1982-01-01

    Recent advances in technology of VLSI circuits enable economical hardware implementation of highly sophisticated signal processing algorithms. This provides the capability of realising a signal processor with uniform hardware for wide real-time applications. The adaption of the VLSI circuits to special application is possible by appropriate microprograms. The processor speed is determined by the arithmetic unit, particularly if floating point

  13. Tablet PCs: A Physical Educator's New Clipboard

    ERIC Educational Resources Information Center

    Nye, Susan B.

    2010-01-01

    Computers in education have come a long way from the abacus of 5,000 years ago to the desktop and laptop computers of today. Computers have transformed the educational environment, and with each new iteration of smaller and more powerful machines come additional advantages for teaching practices. The Tablet PC is one. Tablet PCs are fully…

  14. Enhancing Student Performance Using Tablet Computers

    ERIC Educational Resources Information Center

    Enriquez, Amelito G.

    2010-01-01

    Tablet PCs have the potential to change the dynamics of classroom interaction through wireless communication coupled with pen-based computing technology that is suited for analyzing and solving engineering problems. This study focuses on how tablet PCs and wireless technology can be used during classroom instruction to create an Interactive…

  15. Pharmaceutical Tablet Inspection Emil Sauer Lynge

    E-print Network

    Pharmaceutical Tablet Inspection Emil Sauer Lynge Kongens Lyngby 2012 IMM-B.Sc.-2012-06 #12;Summary (English) The goal of this thesis is to investigate, how an industrial machine vision solution can implementation. The results thus only reects the explanatory power of the tablets spectral response. A method

  16. Putting Tablet PCs to the Test

    ERIC Educational Resources Information Center

    Amirian, Susan

    2004-01-01

    Like many educators, the author and her colleagues (five faculty members and two IT techs) in the department of Media Communications and Technology at East Stroudsburg University in Pennsylvania were interested to find out the status of tablet PCs in education. Microsoft listed 10 manufacturers of tablet PCs following two forms: the slate and the…

  17. Gastric emptying of enteric-coated tablets

    SciTech Connect

    Park, H.M.; Chernish, S.M.; Rosenek, B.D.; Brunelle, R.L.; Hargrove, B.; Wellman, H.N.

    1984-03-01

    To evaluate the gastric emptying time of pharmaceutical dosage forms in a clinical setting, a relatively simple dual-radionuclide technique was developed. Placebo tablets of six different combinations of shape and size were labeled with indium-111 DTPA and enteric coated. Six volunteers participated in a single-blind and crossover study. Tablets were given in the morning of a fasting stomach with 6 oz of water containing /sup 99m/Tc pertechnetate and continuously observed with a gamma camera. A scintigraph was obtained each minute. The results suggested that the size, shape, or volume of the tablet used in this study had no significant effect in the rate of gastric emptying. The tablets emptied erratically and unpredictably, depending upon their time of arrival in the stomach in relation to the occurrence of interdigestive myoelectric contractions. The method described is a relatively simple and accurate technique to allow one to follow the gastric emptying of tablets.

  18. Investigation of excipient type and level on drug release from controlled release tablets containing HPMC.

    PubMed

    Williams, Robert O; Reynolds, Thomas D; Cabelka, Tim D; Sykora, Matthew A; Mahaguna, Vorapann

    2002-05-01

    The purpose of this study was to investigate the influence of excipient type and level on the release of alprazolam formulated in controlled release matrix tablets containing hydroxypropyl methylcellulose (HPMC). Each tablet formulation contained alprazolam, HPMC (Methocel K4MP), excipients, and magnesium stearate. The soluble excipients investigated were lactose monohydrate, sucrose, and dextrose, and the insoluble excipients included dicalcium phosphate dihydrate, dicalcium phosphate anhydrous, and calcium sulfate dihydrate. The similarity factor (f2 factor) was used to compare the dissolution profile of each formulation. The insoluble excipients, especially dicalcium phosphate dihydrate, caused the drug to be released at a slower rate and to a lesser extent than the soluble excipients. Soluble excipients created a more permeable hydrated gel layer for drug release, increased the porosity resulting in faster diffusion of drug, and increased the rate of tablet erosion. Use of binary mixtures of lactose monohydrate and dicalcium phosphate dihydrate produced release profiles of intermediate duration. Rapid drug dissolution was obtained when only 9.1% w/w of lactose monohydrate was present in the tablet formulation. Only when the dicalcium phosphate dihydrate level was sufficiently high (36.5% w/w) was the release rate and extent decreased. It was demonstrated that the type and level of excipient influenced the rate and extent of drug release from controlled release tablets containing HPMC. The release mechanism of alprazolam from each tablet formulation was described by either the Hixson-Crowell cube root kinetics equation or Peppas's equation. However, the different excipient types investigated did not influence the release mechanism of alprazolam from the final tablets. PMID:12066573

  19. [Tramadol/acetaminophen combination tablets].

    PubMed

    Yokotsuka, Shoko; Kato, Jitsu

    2013-07-01

    Tramadol/acetaminophen fixed-dose combination tablets (Tramse) combine tramadol, a centrally acting week opioid analgesic, with low-dose acetaminophen. The action of tramadol may be described as a weak agonist at the mu-opioid receptor, inhibition of serotonin reuptake, and inhibition of noradrenaline reuptake. The second component in these tablets, acetaminophen mainly appears to act through central mechanism. Chronic pain may be broadly classified into nociceptive, neuropathic and mixed. Tramset may exert additive or synergic benefits in treating the multiple mechanism of pain. Clinical studies have revealed its efficacy and safety for a variety of pain condition such as chronic low back pain, rheumatoid arthritis, fibromyalgia and painful diabetic peripheral neuropathy. It is expected that Tramset is going to induce pain relief and to improve disturbance of daily life in patients with intractable chronic pain. However overuse of Tramset may induce severe adverse effects such as addiction, abuse and hepatotoxicity. Therefore clinician should continuously assess pain intensity, activity of daily life, mode of its consumption, and adverse effects after prescription. PMID:23905401

  20. Formulation and optimization of gastric floating drug delivery system using Central composite design and its biopharmaceutical evaluation.

    PubMed

    Meka, Venkata Srikanth; Thing, Lim Kee; Gorajana, Adinarayana; Kolapalli, Venkata Ramana-Murthy

    2015-07-01

    The present work investigates the formulation and biopharmaceutical estimation of gastric floating drug delivery system (GFDDS) of propranolol HCl using semi-synthetic polymer carboxymethyl ethyl cellulose (CMEC) and a synthetic polymer polyethylene oxide (PEO). A central composite design was applied for optimization of polymer quantity (CMEC or PEO) and sodium bicarbonate concentration as independent variables. The dependent variables evaluated were: % of drug release at 1 hr (D1hr), % drug release at 3 hr (D3hr) and time taken for 95% of drug release (t95). Numerical optimization and graphical optimization were conducted to optimize the response variables. All observed responses of statistically optimized formulations were in high treaty with predicted values. Accelerated stability studies were conducted on the optimized formulations at 40±2°C/75% ±5% RH and confirm that formulations were stable. Optimized formulations were evaluated for in vivo buoyancy characterization in human volunteers and were found buoyant in gastric fluid. Gastric residence time was enhanced in the fed but not the fasted state. The optimized formulations and marketed formulation were administered to healthy human volunteers and evaluated for pharmacokinetic parameters. Mean residence time (MRT) was prolonged and AUC levels were increased for both optimized floating tablets when compared with marketed product. High relative bioavailability obtained with optimized gastric floating tablets compared to commercial formulation, indicated the improvement of bioavailability. PMID:26142528

  1. Comparison of the Halving of Tablets Prepared with Eccentric and Rotary Tablet Presses

    Microsoft Academic Search

    T. Sovány; P. Kása Jr.; K. Pintye-Hódi

    2009-01-01

    The aim of this study was to compare the densification of powder mixtures on eccentric and rotary tablet presses and to establish\\u000a relationships with the halving properties of the resulting scored tablets. This is an important problem because the recent\\u000a guidelines of EU require verification of the equal masses of tablet halves. The models of Walker, Heckel, and Kawakita were

  2. Design, development and in-vitro evaluation of metoprolol tartrate tablets containing xanthan-tragacanth.

    PubMed

    Rasul, Akhtar; Iqbal, Muhammad; Murtaza, Ghulam; Waqas, Muhammad K; Hanif, Muhammad; Khan, Shujaat A; Bhatti, Naveed S

    2010-01-01

    The present study was undertaken to develop oral sustained release tablets of metoprolol tartrate using natural hydrophilic matrix formers (xanthan gum and tragacanth). Sustained release matrix tablets of metoprolol tartrate were prepared by using different ratios of drug, xanthan gum and tragacanth. Microcrystalline cellulose (MCC) was used as diluent. The polymer was incorporated into a matrix system using direct compression technique. All the lubricated formulations were compressed using concave punches in compression machine. Compressed tablets were evaluated for diameter, hardness, friability, weight variation and in vitro dissolution using USP dissolution apparatus-II. Different formulations were evaluated with respect to dissolution profile in 900 mL phosphate buffer (pH 6.8), 0.1 M HCl solution and distilled water for 12 h at 37 degrees C. Increasing the amount of polymer (xanthan gum) in the formulation led to slow release of drug and decreasing the amount of polymer gave enhanced release of metoprolol tartrate. The kinetic treatment showed the best fitted different mathematical models (Zero order, First order, Higuchi's and Hixson-Crowell). Most of the solid matrix formulations followed Higuchi or zero order kinetics. The formulations F1, F2, F3 and F7, F8, F9 showed maximum linearity while the formulations F4, F5, F6 were not of linear behavior. The results showed that the formulation F9 containing 30% xanthan gum and 10% gum tragacanth is the most similar to that of the reference marketed preparation. PMID:20873420

  3. High Performance Scientific Computing Using FPGAs with IEEE Floating Point and Logarithmic Arithmetic for Lattice QCD

    Microsoft Academic Search

    Owen Callanan; David Gregg; Andy Nisbet; Mike Peardon

    2006-01-01

    The recent development of large FPGAs along with the availability of a variety of floating point cores have made it possible to implement high-performance matrix and vector kernel operations on FPGAs. In this paper we seek to evaluate the performance of FPGAs for real scientific computations by implementing Lattice QCD, one of the classic scientific computing problems. Lattice QCD is

  4. Use of floating alginate gel beads for stomach-specific drug delivery

    Microsoft Academic Search

    Y Murata; N Sasaki; E Miyamoto; S Kawashima

    2000-01-01

    Two types of alginate gel beads capable of floating in the gastric cavity were prepared. The first, alginate gel bead containing vegetable oil (ALGO), is a hydrogel bead and its buoyancy is attributable to vegetable oil held in the alginate gel matrix. The model drug, metronidazole (MZ), contained in ALGO was released gradually into artificial gastric juice, the release rate

  5. Relational Abstract Domains for the Detection of Floating-Point

    E-print Network

    Miné, Antoine

    ESOP'2004 Relational Abstract Domains for the Detection of Floating-Point Run-Time Errors Antoine-time error. Floating-Point Nowadays, embedded software use floating-point numbers instead of fixed-point. Floating-point numbers are complex, not always understood by programmers. Floating-point numbers

  6. Intel I/O, Floating point o DOS System Calls

    E-print Network

    Biagioni, Edoardo S.

    Intel I/O, Floating point o DOS System Calls o Floating point 2 #12; Floating Point o integer: 1, 2, 3, 4 o fixed point: 100.001, 100.002, 123.456 o floating point: 100 x 103 , 101 x 103 , 123 x 105 o in the floating point

  7. Tablets for Timely Design Documentation

    NSDL National Science Digital Library

    Brown, Cordelia

    One of the biggest challenges we have experienced in supervising digital systems senior design projects is the quality and completeness of the individual lab notebooks. Of the five outcomes we continuously track for this capstone course, the lab notebooks have consistently received the lowest quantitative scores. A significant improvement was achieved three years ago when we transitioned from carbon paper and pen notebooks to on-line (HTML) notebooks. Many teams took advantage of (and put to good use) the ability to post digital pictures of prototyping setups, provide hyperlinks to all their device datasheets, post their latest schematics and software listings for evaluation, and post video clips of their project in action (as verification of their project success criteria). The primary drawback has been the need for students to be in front of a networked computer to make lab notebook entries; consequently, the notebook updates still tended to be done in spurts (typically after the fact) rather than in real time. Project work (and inspiration), in fact, does not always occur in a lab setting, where networked computers are readily available, nor does it occur when all team members are working in the same physical location. Our hypothesis is that equipping each project team with wireless Tablet PCs should not only significantly improve the spontaneity (and regularity) with which the on-line lab notebooks are updated, but also facilitate collaboration among team members working on the design project at different locations. An HP Technology for Teaching Grant has provided a critical mass of Tablet PCs to test this hypothesis. A description of how the equipment provided is being utilized, along with a discussion of the preliminary results obtained, is presented in this paper.

  8. The impact on seaplane floats during landing

    NASA Technical Reports Server (NTRS)

    Von Karman, TH

    1929-01-01

    In order to make a stress analysis of seaplane floats, and especially of the members connecting the floats with the fuselage, it is of great importance to determine the maximum pressure acting on the floats during landing. Here, the author gives a formula for maximum pressures during landing that permits one to apply experimental results to different bodies and different velocities. The author notes that the formula checks very well with experimental results.

  9. Tank Tests of Twin Seaplane Floats

    NASA Technical Reports Server (NTRS)

    Herrman, H; Kempf, G; Kloess, H

    1928-01-01

    The following report contains the most essential data for the hydrodynamic portion of the twin-float problem. The following points were successfully investigated: 1) difference between stationary and nonstationary flow; 2) effect of the shape of the step; 3) effect of distance between floats; 4) effect of nose-heavy and tail-heavy moments; 5) effect of the shape of floats; 6) maneuverability.

  10. Condition and Error Estimates in Numerical Matrix Computations

    SciTech Connect

    Konstantinov, M. M. [University of Architecture, Civil Engineering and Geodesy, 1046 Sofia (Bulgaria); Petkov, P. H. [Technical University of Sofia, 1000 Sofia (Bulgaria)

    2008-10-30

    This tutorial paper deals with sensitivity and error estimates in matrix computational processes. The main factors determining the accuracy of the result computed in floating--point machine arithmetics are considered. Special attention is paid to the perturbation analysis of matrix algebraic equations and unitary matrix decompositions.

  11. Onsite Wastewater Treatment Systems: Tablet Chlorination 

    E-print Network

    Lesikar, Bruce J.

    2008-10-23

    Wastewater that is sprayed onto lawns must first be disinfected to prevent odors and remove disease-causing organisms. This publication explains how tablet chlorinators disinfect wastewater and gives tips on how to maintain them....

  12. Floating Ice-Algal Aggregates below Melting Arctic Sea Ice

    PubMed Central

    Assmy, Philipp; Ehn, Jens K.; Fernández-Méndez, Mar; Hop, Haakon; Katlein, Christian; Sundfjord, Arild; Bluhm, Katrin; Daase, Malin; Engel, Anja; Fransson, Agneta; Granskog, Mats A.; Hudson, Stephen R.; Kristiansen, Svein; Nicolaus, Marcel; Peeken, Ilka; Renner, Angelika H. H.; Spreen, Gunnar; Tatarek, Agnieszka; Wiktor, Jozef

    2013-01-01

    During two consecutive cruises to the Eastern Central Arctic in late summer 2012, we observed floating algal aggregates in the melt-water layer below and between melting ice floes of first-year pack ice. The macroscopic (1-15 cm in diameter) aggregates had a mucous consistency and were dominated by typical ice-associated pennate diatoms embedded within the mucous matrix. Aggregates maintained buoyancy and accumulated just above a strong pycnocline that separated meltwater and seawater layers. We were able, for the first time, to obtain quantitative abundance and biomass estimates of these aggregates. Although their biomass and production on a square metre basis was small compared to ice-algal blooms, the floating ice-algal aggregates supported high levels of biological activity on the scale of the individual aggregate. In addition they constituted a food source for the ice-associated fauna as revealed by pigments indicative of zooplankton grazing, high abundance of naked ciliates, and ice amphipods associated with them. During the Arctic melt season, these floating aggregates likely play an important ecological role in an otherwise impoverished near-surface sea ice environment. Our findings provide important observations and measurements of a unique aggregate-based habitat during the 2012 record sea ice minimum year. PMID:24204642

  13. Modeling International Space Station (ISS) Floating Potentials

    NASA Technical Reports Server (NTRS)

    Ferguson, Dale C.; Gardner, Barbara

    2002-01-01

    The floating potential of the International Space Station (ISS) as a function of the electron current collection of its high voltage solar array panels is derived analytically. Based on Floating Potential Probe (FPP) measurements of the ISS potential and ambient plasma characteristics, it is shown that the ISS floating potential is a strong function of the electron temperature of the surrounding plasma. While the ISS floating potential has so far not attained the pre-flight predicted highly negative values, it is shown that for future mission builds, ISS must continue to provide two-fault tolerant arc-hazard protection for astronauts on EVA.

  14. Clinical Chemical Reagent Tablet Weight Distribution

    Microsoft Academic Search

    E. Melvin Gindler; Robert T. Ishizaki

    A study of the weights of 121 tablets, intended for clinical chemical purposes,showed a normal distribution, with 95% of the tablets being within ±8% of the mean weight (21.8 mg.). The substrate is pH 10.2 (370), falling about 0.6 pH units when serum is added. T1HE1tE APPEAR TO BE virtually no published studies OH the weight (list ributiOllof tabletsintended for

  15. A new brittleness index for compacted tablets.

    PubMed

    Sonnergaard, Jørn M

    2013-12-01

    A dimensionless index that quantifies the brittle or ductile character of tablets is presented. The work of failure (WOF) of crushed or broken flat tablets is calculated by numerical integration of the force-displacement measurement in a flexure tester. The ratio between WOF and the crushing force (F) corrected for the diameter of the tablet (D) is proposed to express the brittle/ductile index (BDI). [Formula: see text] This dimensionless index quantitatively denotes the brittle/ductile character of the compacted material as the normalized deformation in percentage of a cylindrical tablet at the breaking point. For ideal brittle materials, the BDI value will be 0 and for complete plastic deformation, that is, a total compression of the tablet without fracture, BDI will be 100. The validity and discriminative power is demonstrated on mixtures of microcrystalline cellulose and lactose. The robust measure of brittleness with an acceptable accuracy is obtained with only a minor influence of the tablet diameter and the speed of platen. PMID:24258281

  16. Formulation and optimization of potassium iodide tablets

    PubMed Central

    Al-Achi, Antoine; Patel, Binit

    2014-01-01

    The use of potassium iodide (KI) as a protective agent against accidental radioactive exposure is well established. In this study, we aimed to prepare a KI tablet formulation using a direct compression method. We utilized Design of Experiment (DoE)/mixture design to define the best formulation with predetermined physical qualities as to its dissolution, hardness, assay, disintegration, and angle of repose. Based on the results from the DoE, the formulation had the following components (%w/w): Avicel 48.70%, silicon dioxide 0.27%, stearic acid (1.00%), magnesium stearate 2.45%, and dicalcium phosphate 18.69%, in addition to potassium iodide 28.89% (130 mg/tablet). This formulation was scaled-up using two tablet presses, a single-punch press and a rotary mini tablet press. The final scaled-up formulation was subjected to a variety of quality control tests, including photo-stability testing. The results indicate that potassium iodide tablets prepared by a rotary mini tablet press had good pharmaceutical characteristics and a shelf-life of 25 days when stored at room temperature protected from light. PMID:25685048

  17. Formulation and optimization of potassium iodide tablets.

    PubMed

    Al-Achi, Antoine; Patel, Binit

    2015-01-01

    The use of potassium iodide (KI) as a protective agent against accidental radioactive exposure is well established. In this study, we aimed to prepare a KI tablet formulation using a direct compression method. We utilized Design of Experiment (DoE)/mixture design to define the best formulation with predetermined physical qualities as to its dissolution, hardness, assay, disintegration, and angle of repose. Based on the results from the DoE, the formulation had the following components (%w/w): Avicel 48.70%, silicon dioxide 0.27%, stearic acid (1.00%), magnesium stearate 2.45%, and dicalcium phosphate 18.69%, in addition to potassium iodide 28.89% (130 mg/tablet). This formulation was scaled-up using two tablet presses, a single-punch press and a rotary mini tablet press. The final scaled-up formulation was subjected to a variety of quality control tests, including photo-stability testing. The results indicate that potassium iodide tablets prepared by a rotary mini tablet press had good pharmaceutical characteristics and a shelf-life of 25 days when stored at room temperature protected from light. PMID:25685048

  18. The origin of tablet boudinage: Results from experiments using power-law rock analogs

    NASA Astrophysics Data System (ADS)

    Zulauf, J.; Zulauf, G.; Kraus, R.; Gutiérrez-Alonso, G.; Zanella, F.

    2011-10-01

    We used power-law viscous plasticine ( n = ca. 7) as a rock analog to simulate boudinage of rocks undergoing dislocation creep and brittle fracture. A competent plasticine layer, oriented perpendicular to the main shortening direction, Z, underwent bulk pure flattening inside a less competent plasticine matrix. Computer tomographic analyses of the deformed samples revealed that boudinage results from an initial phase of viscous necking followed by tensile failure along the previously formed necks. The resulting boudins display a polygonal shape in plan-view and are referred to as 'tablet boudins' (in contrast to the square to rectangular shaped chocolate-tablet boudins). The ratio between the plan-view long and short axis, R, ranges from 1.2 to 2.6. The polygonal, non-isometric shape of the tablet boudins can be explained by the strong interaction of concentric and radial tensile fractures. With increasing layer thickness, Hi, the mean diameter of the boudin tablets, Wa, increases, while the number of boudins, N, decreases. Progressive finite strain results in a higher number of the boudins and a smaller mean diameter. The thickness of the boudins, Hf, is almost the same as the initial layer thickness, Hi, while the aspect ratio ( Wd = Wa / Hf) decreases with layer thickness and finite strain. The mean Wd values obtained from all experiments span from ca. 4 to ca. 11. Tablet boudins, described in the present paper, have yet not been described from natural outcrops. The reasons might be that pure flattening strain is not common in nature, and the characterization and evaluation of tablet boudins requires geometrical analysis in three dimensions, which is a difficult task when such structures occur in nature.

  19. Suitability of ?-carrageenan pellets for the formulation of multiparticulate tablets with modified release.

    PubMed

    Ghanam, Dima; Kleinebudde, Peter

    2011-05-16

    ?-Carrageenan is a novel pelletisation aid with high formulation robustness and quick disintegration leading to fast drug release unlike the matrix-like release from non-disintegrating microcrystalline cellulose pellets. Compression of pellets into tablets is cost effective. The feasibility of formulating multiparticulate tablets with coated ?-carrageenan pellets was investigated. Pellets containing a highly soluble drug in acid, namely bisacodyl and ?-carrageenan or MCC as pelletisation aid were prepared, enteric coated with a mixture of Kollicoat(®) MAE 30 DP and Eudragit(®) NE 30 D and compressed using silicified microcrystalline cellulose as embedding powder. The effect of coating level, type of pellet core, compression force and punch configurations on drug release were studied. A sufficient coating thickness for ?-carrageenan pellets was necessary to obtain multiparticulate tablets with adequate resistance in the acid stage regardless of the compression pressure used. While ?-carrageenan pellets and their tablets released over 80% of the drug during the neutral stage only about 20-24% was released from MCC pellets and their tablets. The type of punches used (oblong or round) did not significantly influence the drug release from the prepared tablets. Moreover, sufficient prolonged release properties were obtained with ?-carrageenan pellets containing theophylline as a model drug and coated with Kollicoat(®) SR 30 D using Kollicoat(®) IR as pore former. A lower coating level and higher amount of pore former were needed in case of theophylline pellets formulated with MCC as pelletisation aid. The sustained release properties of both coated pellet formulations were maintained after compression at different compression pressures. PMID:21335073

  20. Liquisolid technique as a new approach to sustain propranolol hydrochloride release from tablet matrices.

    PubMed

    Javadzadeh, Yousef; Musaalrezaei, Leila; Nokhodchi, Ali

    2008-10-01

    It is suggested here that liquisolid technique has the potential to be optimized for the reduction of drug dissolution rate and thereby production of sustained release systems. In the present study, propranolol hydrochloride was dispersed in polysorbate 80 as the liquid vehicle. Then a binary mixture of carrier-coating materials (Eudragit RL or RS as the carrier and silica as the coating material) was added to the liquid medication under continuous mixing in a mortar. The final mixture was compressed using the manual tableting machine. The effect of drug concentration, loading factor, thermal treating and aging on release profile of propranolol hydrochloride from liquisolid compacts were investigated at two pH values (1.2 and 6.8). The release rate of propranolol HCl from liquisolid compacts was compared to the release of propranolol HCl from conventional tablets. X-ray crystallography and DSC were used to investigate the formation of any complex between drug and excipients or any crystallinity changes during the manufacturing process. Propranolol HCl tablets prepared by liquisolid technique showed greater retardation properties in comparison with conventional matrix tablets. This investigation provided evidence that polysorbate 80 (Tween 80) has important role in sustaining the release of drug from liquisolid matrices, and a reduction of T(g) of the polymer can be the reason for the release prolongation of liquisolid tablets. The results also showed that wet granulation had remarkable impact on release rate of propranolol HCl from liquisolid compacts, reducing the release rate of drug from liquisolid compacts. The results showed that aging (liquisolid tablets were kept at 25 degrees C/75% relative humidity for 6 months) had no effect on hardness and dissolution profile of drug. The kinetics studies revealed that most of the liquisolid formulations followed the zero-order release pattern. X-ray crystallography and DSC ruled out any changes in crystallinity or complex formation during the manufacturing process of liquisolid formulations. PMID:18647643

  1. 21 CFR 520.1872 - Praziquantel, pyrantel pamoate, and febantel tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Praziquantel, pyrantel pamoate, and febantel tablets. 520.1872 Section 520.1872 Food and...Praziquantel, pyrantel pamoate, and febantel tablets. (a) Specifications . Each tablet or chewable tablet contains either:...

  2. 21 CFR 520.1872 - Praziquantel, pyrantel pamoate, and febantel tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...Praziquantel, pyrantel pamoate, and febantel tablets. 520.1872 Section 520.1872 Food and...Praziquantel, pyrantel pamoate, and febantel tablets. (a) Specifications . Each tablet or chewable tablet contains either:...

  3. 21 CFR 520.82b - Aminopropazine fumarate, neomycin sulfate tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Aminopropazine fumarate, neomycin sulfate tablets. 520.82b Section 520.82b Food...Aminopropazine fumarate, neomycin sulfate tablets. (a) Specifications. The drug is in tablet form. Each tablet contains both...

  4. 21 CFR 520.82b - Aminopropazine fumarate, neomycin sulfate tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...Aminopropazine fumarate, neomycin sulfate tablets. 520.82b Section 520.82b Food...Aminopropazine fumarate, neomycin sulfate tablets. (a) Specifications. The drug is in tablet form. Each tablet contains both...

  5. 33 CFR 143.120 - Floating OCS facilities.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Floating OCS facilities. 143.120 Section...EQUIPMENT OCS Facilities § 143.120 Floating OCS facilities. (a) Before construction is started on a proposed floating OCS facility, the owner...

  6. 33 CFR 143.120 - Floating OCS facilities.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Floating OCS facilities. 143.120 Section...EQUIPMENT OCS Facilities § 143.120 Floating OCS facilities. (a) Before construction is started on a proposed floating OCS facility, the owner...

  7. 33 CFR 143.120 - Floating OCS facilities.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Floating OCS facilities. 143.120 Section...EQUIPMENT OCS Facilities § 143.120 Floating OCS facilities. (a) Before construction is started on a proposed floating OCS facility, the owner...

  8. 33 CFR 143.120 - Floating OCS facilities.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Floating OCS facilities. 143.120 Section...EQUIPMENT OCS Facilities § 143.120 Floating OCS facilities. (a) Before construction is started on a proposed floating OCS facility, the owner...

  9. 33 CFR 143.120 - Floating OCS facilities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Floating OCS facilities. 143.120 Section...EQUIPMENT OCS Facilities § 143.120 Floating OCS facilities. (a) Before construction is started on a proposed floating OCS facility, the owner...

  10. 14 CFR 23.535 - Auxiliary float loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Auxiliary float loads. 23.535 Section 23.535 Aeronautics...COMMUTER CATEGORY AIRPLANES Structure Water Loads § 23.535 Auxiliary float loads. (a) General. Auxiliary floats...

  11. 14 CFR 25.535 - Auxiliary float loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Auxiliary float loads. 25.535 Section 25.535 Aeronautics...TRANSPORT CATEGORY AIRPLANES Structure Water Loads § 25.535 Auxiliary float loads. (a) General. Auxiliary floats...

  12. 14 CFR 25.535 - Auxiliary float loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Auxiliary float loads. 25.535 Section 25.535 Aeronautics...TRANSPORT CATEGORY AIRPLANES Structure Water Loads § 25.535 Auxiliary float loads. (a) General. Auxiliary floats...

  13. 14 CFR 23.535 - Auxiliary float loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Auxiliary float loads. 23.535 Section 23.535 Aeronautics...COMMUTER CATEGORY AIRPLANES Structure Water Loads § 23.535 Auxiliary float loads. (a) General. Auxiliary floats...

  14. 14 CFR 23.535 - Auxiliary float loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Auxiliary float loads. 23.535 Section 23.535 Aeronautics...COMMUTER CATEGORY AIRPLANES Structure Water Loads § 23.535 Auxiliary float loads. (a) General. Auxiliary floats...

  15. 14 CFR 23.535 - Auxiliary float loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Auxiliary float loads. 23.535 Section 23.535 Aeronautics...COMMUTER CATEGORY AIRPLANES Structure Water Loads § 23.535 Auxiliary float loads. (a) General. Auxiliary floats...

  16. 14 CFR 25.535 - Auxiliary float loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Auxiliary float loads. 25.535 Section 25.535 Aeronautics...TRANSPORT CATEGORY AIRPLANES Structure Water Loads § 25.535 Auxiliary float loads. (a) General. Auxiliary floats...

  17. 14 CFR 23.535 - Auxiliary float loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Auxiliary float loads. 23.535 Section 23.535 Aeronautics...COMMUTER CATEGORY AIRPLANES Structure Water Loads § 23.535 Auxiliary float loads. (a) General. Auxiliary floats...

  18. 14 CFR 25.535 - Auxiliary float loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Auxiliary float loads. 25.535 Section 25.535 Aeronautics...TRANSPORT CATEGORY AIRPLANES Structure Water Loads § 25.535 Auxiliary float loads. (a) General. Auxiliary floats...

  19. 14 CFR 25.535 - Auxiliary float loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Auxiliary float loads. 25.535 Section 25.535 Aeronautics...TRANSPORT CATEGORY AIRPLANES Structure Water Loads § 25.535 Auxiliary float loads. (a) General. Auxiliary floats...

  20. Smooth Planning for Free-floating Space Robots Using Polynomials *

    E-print Network

    Papadopoulos, Evangelos

    Smooth Planning for Free-floating Space Robots Using Polynomials * Evangelos Papadopoulos, Ioannis) is acknowledged. Abstract Free-floating space manipulator systems, have spacecraft actuators turned off free­floating space manipulator systems is developed that allows simultaneous manipulator end

  1. Coupled Dynamic Analysis of Multiple Unit Floating Offshore Wind Turbine

    E-print Network

    Bae, Yoon Hyeok

    2013-04-23

    floating wind turbines, so the effects of such high-frequency excitations from the tower and blades need to be checked. 5 Another concept for floating offshore wind farms is the Multiple Unit Floating Offshore Wind Turbine (MUFOWT). This model...

  2. Floating patella associated with lymphoedema

    PubMed Central

    Vun, Shen Hwa; Bayam, Levent; Drampalos, Efstathios; Jesry, Mohammed; Fadel, George

    2015-01-01

    Ipsilateral injury of more than one component of the knee extensor apparatus is rare. It is mostly associated with previous trauma, surgery, immunosuppression therapy and systemic disease. We present the first documented case of a spontaneous bifocal disruption of the knee extensor apparatus (i.e. floating patella) associated with lymphoedema. This case highlights the importance of considering lymphoedema as another risk factor for rupture of the knee extensor apparatus. It also highlights the importance of assessing all components of the knee extensor apparatus in patients presenting with acute knee injuries. PMID:25802253

  3. Bioequivalence study of atorvastatin tablets.

    PubMed

    Koytchev, Rossen; Ozalp, Yildiz; Erenmemisoglu, Aydin; van der Meer, Mike John; Alpan, Recep Serdar

    2004-09-01

    The study was designed to evaluate the relative bioavailability of two formulations of atorvastatin (CAS 134523-03-8). A bioequivalence study was carried out in 24 healthy male volunteers who received four 10 mg tablets of the test formulation (Kolestor) and the same dose of the originator product. The trial was performed according to an open, crossover design with a wash-out period of 7 days in one study center. Blood samples were taken up to 48 h post dose, the plasma was separated and the concentrations of atorvastatin were determined by HPLC-MS-MS method. The mean Cmax were 16.37 ng/mL and 17.05 ng/mL, while the mean AUC0-t were 103.61 ng x h/mL and 102.55 ng x h/mL for the test and reference formulations, respectively. The mean AUC0-inf were 118.10 ng x h/mL and 117.13 ng x h/mL for the test and reference formulations, respectively. The median tmax was 0.67 h for both the test tablet and the reference product. The mean t(1/2 el) was 11.85 h for the test formulation and 13.28 h for the reference formulation. No significant differences of pharmacokinetic parameters between the two studied formulations were found. The 90% confidence intervals for the primary target parameters, intra-individual ratios of AUC0-t and Cmax of atorvastatin, were between 0.85 and 1.05 (AUC0-t) and between 0.84 and 1.23 (Cmax), respectively, and thus within the acceptance ranges. Concerning the secondary parameter tmax the 90% confidence interval for the intra-individual differences was between -0.17 and 0.17 h. In the light of the present study it can be concluded that the two evaluated atorvastatin formulations, i.e. test formulation of atorvastatin and reference preparation are bioequivalent in terms of the rate and extent of absorption. PMID:15497662

  4. Instrumentation for diode laser spectroscopy using 32-bit microcontrollers and a Nexus 7 Android tablet

    NASA Astrophysics Data System (ADS)

    Eyler, Edward

    2013-05-01

    Last year, I described a low-cost ramp and timing generator using a 32-bit microcontroller, connected via USB to an Android tablet that provides a bidirectional touch-screen interface. I have since developed several additional designs to support experiments involving diode laser spectroscopy and cold atom manipulation. One circuit card can be used either as a high-resolution temperature controller or as a dual high-voltage driver for PZT positioners. A second provides a flexible user interface to commercial laser current driver modules, with support for floating ground connections. A third supports a pair of inexpensive rf frequency synthesizer chips (ADF4351) that are usable from 35-4000 MHz. A fast rf switch provides numerous options, including phase-coherent frequency shifting at MHz rates for high-bandwidth laser stabilization and studies of polychromatic optical forces. Additional circuits for laser frequency locking are under development. All of these devices are controllable from a Google Nexus 7 tablet, which is inexpensive yet has graphics processing speeds that allow seamless real-time updates of charts and oscilloscope-like displays. Last year, I described a low-cost ramp and timing generator using a 32-bit microcontroller, connected via USB to an Android tablet that provides a bidirectional touch-screen interface. I have since developed several additional designs to support experiments involving diode laser spectroscopy and cold atom manipulation. One circuit card can be used either as a high-resolution temperature controller or as a dual high-voltage driver for PZT positioners. A second provides a flexible user interface to commercial laser current driver modules, with support for floating ground connections. A third supports a pair of inexpensive rf frequency synthesizer chips (ADF4351) that are usable from 35-4000 MHz. A fast rf switch provides numerous options, including phase-coherent frequency shifting at MHz rates for high-bandwidth laser stabilization and studies of polychromatic optical forces. Additional circuits for laser frequency locking are under development. All of these devices are controllable from a Google Nexus 7 tablet, which is inexpensive yet has graphics processing speeds that allow seamless real-time updates of charts and oscilloscope-like displays. Supported in part by the National Science Foundation.

  5. Future float zone development in industry

    NASA Technical Reports Server (NTRS)

    Sandfort, R. M.

    1980-01-01

    The present industrial requirements for float zone silicon are summarized. Developments desired by the industry in the future are reported. The five most significant problems faced today by the float zone crystal growth method in industry are discussed. They are economic, large diameter, resistivity uniformity, control of carbon, and swirl defects.

  6. Whatever Floats Your Boat: A Design Challenge

    ERIC Educational Resources Information Center

    Kornoelje, Joanne; Roman, Harry T.

    2012-01-01

    This article presents a simple design challenge, based on the PBS program "Design Squad's" "Watercraft" activity that will prove engaging to most technology and engineering students. In this floating boat challenge, students are to build a boat that can float and support 25 pennies for at least 10 seconds--without leaking, sinking, or tipping…

  7. Algorithms for arbitrary precision floating point arithmetic

    Microsoft Academic Search

    Douglas M. Priest

    1991-01-01

    The author presents techniques for performing computations of very high accuracy using only straightforward floating-point arithmetic operations of limited precision. The validity of these techniques is proved under very general hypotheses satisfied by most implementations of floating-point arithmetic. To illustrate the applications of these techniques, an algorithm is presented which computes the intersection of a line and a line segment.

  8. Floating Entanglement Witness Measure and Genetic Algorithm

    E-print Network

    A. Baghbanpourasl; G. Najarbashi; M. Seyedkazemi

    2007-08-27

    In this paper based on the notion of entanglement witness, a new measure of entanglement called floating entanglement witness measure is introduced which satisfies some of the usual properties of a good entanglement measure. By exploiting genetic algorithm, we introduce a classical algorithm that computes floating entanglement witness measure. This algorithm also provides a method for finding entanglement witness for a given entangled state.

  9. Towards sensible floating-point arithmetic

    SciTech Connect

    Cody, W.J.

    1980-01-01

    Efforts to promote the development of high-quality transportable numerical software show that few, if any, of the floating-point arithmetic systems in existing computers are completely satisfactory for serious numerical computation. Examination of the defects in these systems leads to specifications for a sensible floating-point system from a numerical analyst's viewpoint. 1 table.

  10. Effect of repeated compaction of tablets on tablet properties and work of compaction using an instrumented laboratory tablet press.

    PubMed

    Gamlen, Michael John Desmond; Martini, Luigi G; Al Obaidy, Kais G

    2015-01-01

    The repeated compaction of Avicel PH101, dicalcium phosphate dihydrate (DCP) powder, 50:50 DCP/Avicel PH101 and Starch 1500 was studied using an instrumented laboratory tablet press which measures upper punch force, punch displacement and ejection force and operates using a V-shaped compression profile. The measurement of work compaction was demonstrated, and the test materials were ranked in order of compaction behaviour Avicel PH101?>?DCP/Avicel PH101?>?Starch?>?DCP. The behaviour of the DCP/Avicel PH101 mixture was distinctly non-linear compared with the pure components. Repeated compaction and precompression had no effect on the tensile fracture strength of Avicel PH101 tablets, although small effects on friability and disintegration time were seen. Repeated compaction and precompression reduced the tensile strength and the increased disintegration time of the DCP tablets, but improved the strength and friability of Starch 1500 tablets. Based on the data reported, routine laboratory measurement of tablet work of compaction may have potential as a critical quality attribute of a powder blend for compression. The instrumented press was suitable for student use with minimal supervisor input. PMID:24171692

  11. Tramadol extended-release tablets.

    PubMed

    Hair, Philip I; Curran, Monique P; Keam, Susan J

    2006-01-01

    Tramadol is a synthetic, centrally acting opioid analgesic. An extended-release tablet formulation of tramadol (tramadol ER) allows gradual release of the active drug, permitting once-daily administration. Tramadol ER administered once daily is equivalent in bioavailability to immediate-release tramadol administered four times daily, with prolonged absorption and lower peak plasma concentrations. Tramadol ER was significantly more effective than placebo in the treatment of moderate to moderately severe chronic pain in patients with osteoarthritis of the knee and/or hip in randomised, double-blind, placebo-controlled trials. In a flexible-dose trial in patients with osteoarthritis of the knee, the mean reduction from baseline in pain intensity scores over 12 weeks was significantly greater in recipients of tramadol ER than in placebo recipients. In a fixed-dose trial in patients with osteoarthritis of the knee and/or hip, the mean improvements from baseline in the pain and physical function subscale scores of the Western Ontario and McMaster Universities Osteoarthritis Index over 12 weeks were significantly greater in tramadol ER than placebo recipients. Common adverse events reported in patients with moderate to moderately severe chronic pain treated with tramadol ER 100-300 mg once daily were dizziness (excluding vertigo), nausea, constipation, somnolence and flushing. PMID:17100415

  12. Floating-Point Matrix Multiplication in a Polymorphic Processor

    E-print Network

    Kuzmanov, Georgi

    and of the applications using it. In this paper, we address a reconfigurable coprocessor extension of a General Purpose, proposed in [1], with the major difference that we consider a tightly coupled co-processor architectural multiplier with 9 process- ing elements, organized in a CCU running at 100 MHz on an XC2VP30­6 FPGA. Our

  13. Testing lyoequivalency for three commercially sustained-release tablets containing diltiazem hydrochloride.

    PubMed

    Maswadeh, Hamzah A; Al-Hanbali, Othman A; Kanaan, Reem A; Shakya, Ashok K; Maraqa, Anwar

    2010-01-01

    In vitro release kinetics of three commercially available sustained release tablets (SR) diltiazem hydrochloride were studied at pH 1.1 for 2 h and for another 6 h at pH 6.8 using the USP dissolution apparatus with the paddle assemble. The kinetics of the dissolution process was studied by analyzing the dissolution data using five kinetic equations: the zero-order equation, the first-order equation, the Higuchi square root equation, the Hixson-Crowell cube root law and the Peppas equation. Analyses of the dissolution kinetic data for diltiazem hydrochloride commercial SR tablets showed that both Dilzacard and Dilzem SR tablets released drug by Non-Fickian (Anomalous transport) release with release exponent (n) equal to 0.59 and 0.54, respectively, which indicate the summation of both diffusion and dissolution controlled drug release. Bi-Tildiem SR tablets released drug by super case II (n = 1.29) which indicate zero-order release due to the dissolution of polymeric matrix and relaxation of the polymer chain. This finding was also in agreement with results obtained from application of zero-order and Hixson-Crowell equations. A dissolution profile comparative study was done to test the lyoequivelancy of the three products by using the mean dissolution time (MDT), dissimilarity factor f1 and similarity factor f2. Results showed that the three products are different and not lyoequivalent. PMID:20210085

  14. Encapsulation of floating carbon nanotubes in SiO2

    NASA Astrophysics Data System (ADS)

    Tsetseris, Leonidas; Pantelides, Sokrates

    2007-03-01

    In many applications of carbon nanotubes (CNT), it is desirable to have them embedded in a dielectric such as SiO2, without significantly impacting their electronic properties. Here we study the CNT-SiO2 interface of an embedded CNT using first-principles calculations. Our results suggest that a carbon nanotube can be incorporated inside a SiO2 matrix that nucleates around it through the formation of Si-O-C bridges. The large distortion associated with the formation of these bridges can be alleviated by hydrogenation of the composite. Introduction of hydrogen in the vicinity of the bridges leads to their elimination, whereby the nanotube loses its anchoring to the matrix and it floats. For CNTs of suitable diameter, the final floating structure has electronic properties very close to the structure in vacuum. Overall, our results provide atomic-scale information that is relevant to a broad range of applications using embedded or adsorbed nanotubes, for example, sensors, electronics, actuators, and CNT coatings. This work was supported in part by DOE Grant DEFG0203ER46096.

  15. SANCTUARY : asymmetric interfaces for game-based tablet learning

    E-print Network

    Haas, Jason M. (Jason Matthew)

    2013-01-01

    This thesis describes the production of Sanctuary, a multiplayer learning game to be played on two tablet computers. Sanctuary's principle innovation is the splitting of the user interface onto two tablets, separating ...

  16. 21 CFR 520.2610 - Trimethoprim and sulfadiazine tablets.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 false Trimethoprim and sulfadiazine tablets. 520.2610 Section 520...DRUGS § 520.2610 Trimethoprim and sulfadiazine tablets. (a) Specifications...of trimethoprim and 25 milligrams of sulfadiazine), 120 milligrams (20...

  17. 21 CFR 520.2610 - Trimethoprim and sulfadiazine tablets.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 false Trimethoprim and sulfadiazine tablets. 520.2610 Section 520...DRUGS § 520.2610 Trimethoprim and sulfadiazine tablets. (a) Specifications...of trimethoprim and 25 milligrams of sulfadiazine), 120 milligrams (20...

  18. 21 CFR 520.2610 - Trimethoprim and sulfadiazine tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Trimethoprim and sulfadiazine tablets. 520.2610 Section 520...DRUGS § 520.2610 Trimethoprim and sulfadiazine tablets. (a) Specifications...of trimethoprim and 25 milligrams of sulfadiazine), 120 milligrams (20...

  19. 21 CFR 520.2610 - Trimethoprim and sulfadiazine tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Trimethoprim and sulfadiazine tablets. 520.2610 Section 520...DRUGS § 520.2610 Trimethoprim and sulfadiazine tablets. (a) Specifications...of trimethoprim and 25 milligrams of sulfadiazine), 120 milligrams (20...

  20. 21 CFR 520.2610 - Trimethoprim and sulfadiazine tablets.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 false Trimethoprim and sulfadiazine tablets. 520.2610 Section 520...DRUGS § 520.2610 Trimethoprim and sulfadiazine tablets. (a) Specifications...of trimethoprim and 25 milligrams of sulfadiazine), 120 milligrams (20...

  1. 21 CFR 520.62 - Aminopentamide hydrogen sulphate tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Aminopentamide hydrogen sulphate tablets. 520.62 Section...ANIMAL DRUGS § 520.62 Aminopentamide hydrogen sulphate tablets. (a) Chemical name...Dimethylamino)-2,2-diphenylvaleramide hydrogen sulfate. (b) Specifications....

  2. Design and evaluation of a specific, bi-phase extended release system based on differently coated mini-tablets.

    PubMed

    Aleksovski, Aleksandar; Luštrik, Matevž; Šibanc, Rok; Dreu, Rok

    2015-07-30

    Mini-tablets are gaining great attention as systems capable of being formulated into multiple unit systems providing a specific drug release pattern. Within the presented research a combined, multiple-unit system, based on different coated matrix mini-tablets, has been developed in order to achieve 24-h specific sigmoid extended release of the model drug paliperidone. The mini-tablets were based on different amounts of polyvinyl acetate/polyvinyl pyrolidone mixture as the matrix former, providing extended release, and two different types of pH-dependent, acrylic polymer coatings, providing delay in release onset, and thus achieving the required specific sigmoid release pattern imposed by the original drug on the market. The selected formulation proved to be consistent with pharmacopoeial requirements. It was also in vitro similar (f2) to the original drug and the theoretical linear release profile, as well as robust and reproducible regarding in vitro release in different fasted gastro-intestinal conditions. This is proof of concept that 24-h, specific, and almost linear release profile of drugs with high solubility can be achieved by employing technology of coated matrix mini-tablets. PMID:25845632

  3. 21 CFR 520.2345b - Tetracycline tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Tetracycline tablets. 520.2345b Section 520.2345b Food...ANIMAL DRUGS § 520.2345b Tetracycline tablets. (a) Specifications. Each tablet contains 100, 250, or 500 milligrams of...

  4. 21 CFR 520.2345b - Tetracycline tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Tetracycline tablets. 520.2345b Section 520.2345b Food...ANIMAL DRUGS § 520.2345b Tetracycline tablets. (a) Specifications. Each tablet contains 100, 250, or 500 milligrams of...

  5. Formulation Optimization of Hydrodynamically Balanced Oral Controlled Release Bioadhesive Tablets of Tramadol Hydrochloride

    PubMed Central

    Singh, Bhupinder; Rani, Ashu; Babita; Ahuja, Naveen; Kapil, Rishi

    2010-01-01

    The directly compressible floating-bioadhesive tablets of tramadol were formulated using varying amounts Carbopol 971P (CP) and hydroxy-propylmethyl cellulose (HPMC), along with other requisite excipients. In vitro drug release profile, floatational characteristics and ex vivo bioadhesive strength using texture analyzer were determined, and systematically optimized using a 32 central composite design (CCD). The studies indicated successful formulation of gastroretentive compressed matrices with excellent controlled release, mucoadhesion and hydrodynamic balance. Comparison of the dissolution profiles of the optimized formulation, with optimal composition of CP:HPMC :: 80.0:125.0, with that of the marketed controlled release formulation other indicated analogy of drug release performance with each other. Validation of optimization study using eight confirmatory experimental runs indicated very high degree of prognostic ability of CCD with mean ± SEM of ?0.06% ± 0.37. Further, the study successfully unravels the effect of the polymers on the selected response variables. PMID:21179349

  6. Supergravity Solutions from Floating Branes

    E-print Network

    Iosif Bena; Stefano Giusto; Clement Ruef; Nicholas P. Warner

    2009-10-12

    We solve the equations of motion of five-dimensional ungauged supergravity coupled to three U(1) gauge fields using a floating-brane Ansatz in which the electric potentials are directly related to the gravitational warp factors. We find a new class of non-BPS solutions, that can be obtained linearly starting from an Euclidean four-dimensional Einstein-Maxwell base. This class - the largest known so far - reduces to the BPS and almost-BPS solutions in certain limits. We solve the equations explicitly when the base space is given by the Israel-Wilson metric, and obtain solutions describing non-BPS D6 and anti-D6 branes kept in equilibrium by flux. We also examine the action of spectral flow on solutions with an Israel-Wilson base and show that it relates these solutions to almost-BPS solutions with a Gibbons-Hawking base.

  7. WindWaveFloat Final Report

    SciTech Connect

    Alla Weinstein, Dominique Roddier, Kevin Banister

    2012-03-30

    Principle Power Inc. and National Renewable Energy Lab (NREL) have completed a contract to assess the technical and economic feasibility of integrating wave energy converters into the WindFloat, resulting in a new concept called the WindWaveFloat (WWF). The concentration of several devices on one platform could offer a potential for both economic and operational advantages. Wind and wave energy converters can share the electrical cable and power transfer equipment to transport the electricity to shore. Access to multiple generation devices could be simplified, resulting in cost saving at the operational level. Overall capital costs may also be reduced, provided that the design of the foundation can be adapted to multiple devices with minimum modifications. Finally, the WindWaveFloat confers the ability to increase energy production from individual floating support structures, potentially leading to a reduction in levelized energy costs, an increase in the overall capacity factor, and greater stability of the electrical power delivered to the grid. The research conducted under this grant investigated the integration of several wave energy device types into the WindFloat platform. Several of the resulting system designs demonstrated technical feasibility, but the size and design constraints of the wave energy converters (technical and economic) make the WindWaveFloat concept economically unfeasible at this time. Not enough additional generation could be produced to make the additional expense associated with wave energy conversion integration into the WindFloat worthwhile.

  8. Program Converts VAX Floating-Point Data To UNIX

    NASA Technical Reports Server (NTRS)

    Alves, Marcos; Chapman, Bruce; Chu, Eugene

    1996-01-01

    VAX Floating Point to Host Floating Point Conversion (VAXFC) software converts non-ASCII files to unformatted floating-point representation of UNIX machine. This is done by reading bytes bit by bit, converting them to floating-point numbers, then writing results to another file. Useful when data files created by VAX computer must be used on other machines. Written in C language.

  9. Performance Boundaries of Massive Floating Car Data Offloading

    E-print Network

    Paris-Sud XI, Université de

    Performance Boundaries of Massive Floating Car Data Offloading Silvia Ancona1,3 and Razvan Stanica1Politecnico di Bari, Bari, Italy Floating Car Data (FCD) consist of information generated by moving vehicles networks, floating car data, cellular uplink 1 Introduction The term Floating Car Data (FCD) defines

  10. FLOATING PLANT AND MARINE ACTIVITIES Table Of Contents

    E-print Network

    US Army Corps of Engineers

    EM 385-1-1 XX Sep 13 i Section 19 FLOATING PLANT AND MARINE ACTIVITIES Table Of Contents Section-1 SECTION 19 FLOATING PLANT and MARINE ACTIVITIES 19.A GENERAL 19.A.01 Floating plant inspection and certification. a. All floating plant regulated by the USCG shall have required USCG documentation

  11. FLOATING GATE COMPARATOR WITH AUTOMATIC OFFSET MANIPULATION FUNCTIONALITY

    E-print Network

    Maryland at College Park, University of

    FLOATING GATE COMPARATOR WITH AUTOMATIC OFFSET MANIPULATION FUNCTIONALITY Eric Liu Wong, Pamela A nonvolatile floating gate charge storage for either offset nulling or au- tomatic programming of a desired is a constant value, it is natu- ral to store it using nonvolatile storage on a floating gate. Floating gate

  12. Research on floating wind turbines: a literature survey

    Microsoft Academic Search

    C. M. Wang; T. Utsunomiya; S. C. Wee; Y. S. Choo

    2010-01-01

    This article presents a literature survey of research and development on floating wind turbines. The various, proposed conceptual designs for floating platforms used for floating wind turbines are described and the working principles of these various floater concepts are outlined. This is followed by an overview of the research work that has been undertaken pertaining to floating wind turbine technology

  13. Three-dimensional modeling to determine properties of tableting materials on rotary machines using a rotary tableting machine simulator

    Microsoft Academic Search

    Katharina M Picker

    2000-01-01

    A new three-dimensional modeling technique of tableting data has been used for data measured with a rotary tableting machine simulator. The use of the tableting machine simulator is helpful in this case because a scale up or a change of equipment is easily possible. The model substances used were hydroxypropyl methylcellulose (HPMC 15.000), microcrystalline cellulose (Avicel PH 101), dicalcium phosphate

  14. Potential of carnuba wax in ameliorating brittle fracture during tableting.

    PubMed

    Uhumwangho, M U; Okor, R S; Adogah, J T

    2009-01-01

    Carnuba wax (as binder) forms hard tablets even at low compression load attributable to its high plasticity. The aim of the present study is to investigate its potential in ameliorating brittle fracture (i.e., lamination and capping) a problem often encountered during tableting. Granules of paracetamol (test drug) were made by triturating the drug powder with the melted wax or starch mucilage (20%w/v). Resulting granules were separated into different size fractions which were separately compressed into tablets with and without a centre hole (as in- built defect) using different compression loads. The tablets were evaluated for tensile strength and the data used to calculate the brittle fracture index (BFI), using the expression: BFI = 0.5(T/T(0)-1) where T0 and T are the tensile strength of tablets with and without a centre hole respectively. The BFI values were significantly lower (p<0.05) in tablets made with carnuba wax compared with tablets made with maize starch as binders. Increase in particle size of the granules or lowering of the compression load further ameliorated the brittle fracture tendency of the tablets. Using granules with the larger particle size (850microm) and applying the lowest unit of load (6 arbitrary unit on the load scale of the tableting machine) the BFI values were 0.03 (carnuba wax tablets) and 0.11 (maize starch tablets). When the conditions were reversed (i.e., a highest load, 8 units and the smallest particle size, 212microm) the BFI values now became 0.17 (carnuba wax tablets) and 0.26 (maize starch tablets). The indication is that the use of large granules and low compression loads to form tablets can further enhance the potential of carnuba wax in ameliorating brittle fracture tendency of tablets during their manufacture. PMID:19168422

  15. Water hyacinth: a possible alternative rate retarding natural polymer used in sustained release tablet design.

    PubMed

    Khatun, Sabera; Sutradhar, Kumar B

    2014-01-01

    In recent years natural polymers have been widely used because of their effectiveness and availability over synthetic polymers. In this present investigation matrix tablets of Metformin hydrochloride were formulated using Water hyacinth powder and its rate retardant activity was studied. Tablets were prepared using wet granulation method with 8% starch as granulating agent and 5, 10, 15, 20, 25 and 30% of Water hyacinth powder to the drug. In preformulation study, angle of repose, Carr's Index and Hausner ratio were calculated. Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), and Scanning Electron Microscopy (SEM) studies were performed and no interactions were found between drug and excipients. Weight variation, friability, hardness, thickness, diameter, and in vitro release study were performed with the prepared matrix tablets. Dissolution studies were conducted using USP type II apparatus at a speed of 100 rpm at 37°C ± 0.5 temperature for 8 h. Though all the formulations comply with both BP and USP requirements, formulation F-1 (5% of Water hyacinth) was the best fitted formula. The drug release patterns were explained in different kinetic models such as Zero order, First order, Higuchi, Hixson Crowell, and Korsmeyer-Peppas equations. The current investigation implies that Water hyacinth has the potential to be used as a rate-retarding agent in sustained release drug formulations. PMID:24966835

  16. Pulse release of doxazosin from hydroxyethylcellulose compression coated tablet: mechanistic and in vivo study.

    PubMed

    Biswas, Nikhil; Guha, Arijit; Sahoo, Ranjan Kumar; Kuotsu, Ketousetuo

    2015-01-01

    Chronotherapeutically programmed hydroxyethylcellulose (HEC) based compression coated doxazosin tablets were prepared and the influence of disintegrants croscarmellose sodium, L-hydroxypropylcellulose (L-HPC), gellan gum on drug release and in vivo performance were investigated. Infrared spectroscopy and differential scanning calorimetric studies did not indicate any excipient incompatibility in the tablets. The disintegrants induced a continuous water influx resulting in a rapid expansion of the membrane. The subsequent formation of fractures into the coats leads to a fast drug release after an initial lag time. Release rates indicated that croscarmellose sodium and L-HPC were directly proportional to their concentration in the formulations. In vitro optimized croscarmellose sodium-HEC matrix showed significantly faster (p < 0.05) drug release (t90% = 46 min) after an initial lag of 243 min. Disintegrant-HEC blended matrices were found significantly superior (p < 0.05) in terms of in vitro release and bioavailability in comparison to plain HEC matrices. Drug release kinetics followed modified power law and Weibull model (r > 0.99). The mechanism involved in release was anomalous transport and super case II transport with matrix swelling. The pulsatile tablets showed no changes either in physicochemical appearance, drug content or in dissolution pattern during its accelerated stability studies. PMID:25179280

  17. Formulation and Evaluation of Chondroitin Sulphate Tablets of Aceclofenac for Colon Targeted Drug Delivery

    PubMed Central

    Ramasamy, Thiruganesh; Subbaih Khandasamy, Umadevi; Shanmugam, Suresh; Ruttala, Himabindhu

    2012-01-01

    The aim of the present study was to develop a single unit, site-specific matrix tablets of aceclofenac allowing targeted drug release in the colon with a microbially degradable polymeric carrier, chondroitin suphate (CS) and to coat the optimized batches with a pH dependent polymeric. The tablets were prepared by wet granulation method using starch mucilage as a binding agent and HPMC K-100 as a swellable polymer. Chondroitin Sulphate and drug and physical mixture were characterized by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The tablets were tested for their in-vitro dissolution characteristics in various simulated gastric fluids for their suitability as a colon-specific drug delivery system and also the tablets were evaluated for physicochemical properties, drug content, water percentage swelling and erosion characteristics. The dissolution data demonstrates that the 10% w/w increase in coating level of the pH dependent polymer (Eudragit L-100 and Eudragit S-100 in a ratio of 1 : 4 prevented the drug release in the simulated gastric fluid (pH 1.2-SGF) and the simulated intestinal fluid (pH 7.4-SIF). The dissolution rate of the tablet is dependent upon the concentration of Chondroitin sulphate in the simulated colonic fluid (SCF). The rapid increase in release of aceclofenac in SCF was revealed as due to the degradation of the Chondroitin sulphate membrane by bacterial enzymes. The studies confirmed that, the designed system could be used potentially as a carrier for colon delivery of aceclofenac by regulating drug release in stomach and the small intestine. PMID:24250470

  18. A floating-point technique for extending the available precision

    Microsoft Academic Search

    T. J. Dekker

    1971-01-01

    A technique is described for expressing multilength floating-point arithmetic in terms of singlelength floating point arithmetic, i.e. the arithmetic for an available (say: single or double precision) floating-point number system. The basic algorithms are exact addition and multiplication of two singlelength floating-point numbers, delivering the result as a doublelength floating-point number. A straight-forward application of the technique yields a set

  19. Exploring Floating Concrete and Beam Design.

    ERIC Educational Resources Information Center

    Snell, Billie G.; Snell, Luke M.

    2002-01-01

    Presents two construction activities that address both state and federal science standards and encourage students to consider career options in mathematics and science. Includes floating concrete and paper bridge activities. (YDS)

  20. Verification of floating-point software

    NASA Technical Reports Server (NTRS)

    Hoover, Doug N.

    1990-01-01

    Floating point computation presents a number of problems for formal verification. Should one treat the actual details of floating point operations, or accept them as imprecisely defined, or should one ignore round-off error altogether and behave as if floating point operations are perfectly accurate. There is the further problem that a numerical algorithm usually only approximately computes some mathematical function, and we often do not know just how good the approximation is, even in the absence of round-off error. ORA has developed a theory of asymptotic correctness which allows one to verify floating point software with a minimum entanglement in these problems. This theory and its implementation in the Ariel C verification system are described. The theory is illustrated using a simple program which finds a zero of a given function by bisection. This paper is presented in viewgraph form.

  1. Notes 11. High pressure floating ring seals 

    E-print Network

    San Andres, Luis

    2009-01-01

    Floating ring seals for compressors: leakage and force coefficients, seal lock up and effect on rotor stability, recommendations to reduce seal cross-coupled effects. Long oil seals as pressure barriers in industrial mixers: leakage and force...

  2. Atraumatic floating clavicle and total claviculectomy.

    PubMed

    Attarian, D E

    1999-01-01

    We describe a patient with a floating clavicle of atraumatic origin treated by total claviculectomy. Clavicular function and anatomy are summarized relative to complete excision. Other treatment options for panclavicular instability are also discussed. PMID:12132804

  3. Swelling/Floating Capability and Drug Release Characterizations of Gastroretentive Drug Delivery System Based on a Combination of Hydroxyethyl Cellulose and Sodium Carboxymethyl Cellulose

    PubMed Central

    Chen, Ying-Chen; Ho, Hsiu-O; Liu, Der-Zen; Siow, Wen-Shian; Sheu, Ming-Thau

    2015-01-01

    The aim of this study was to characterize the swelling and floating behaviors of gastroretentive drug delivery system (GRDDS) composed of hydroxyethyl cellulose (HEC) and sodium carboxymethyl cellulose (NaCMC) and to optimize HEC/NaCMC GRDDS to incorporate three model drugs with different solubilities (metformin, ciprofloxacin, and esomeprazole). Various ratios of NaCMC to HEC were formulated, and their swelling and floating behaviors were characterized. Influences of media containing various NaCl concentrations on the swelling and floating behaviors and drug solubility were also characterized. Finally, release profiles of the three model drugs from GRDDS formulation (F1-4) and formulation (F1-1) were examined. Results demonstrated when the GRDDS tablets were tested in simulated gastric solution, the degree of swelling at 6 h was decreased for each formulation that contained NaCMC in comparison to those in de-ionized water (DIW). Of note, floating duration was enhanced when in simulated gastric solution compared to DIW. Further, the hydration of tablets was found to be retarded as the NaCl concentration in the medium increased resulting in smaller gel layers and swelling sizes. Dissolution profiles of the three model drugs in media containing various concentrations of NaCl showed that the addition of NaCl to the media affected the solubility of the drugs, and also their gelling behaviors, resulting in different mechanisms for controlling a drug’s release. The release mechanism of the freely water-soluble drug, metformin, was mainly diffusion-controlled, while those of the water-soluble drug, ciprofloxacin, and the slightly water-soluble drug, esomeprazole, were mainly anomalous diffusion. Overall results showed that the developed GRDDS composed of HEC 250HHX and NaCMC of 450 cps possessed proper swelling extents and desired floating periods with sustained-release characteristics. PMID:25617891

  4. Travel Time Estimation Using Floating Car Data

    E-print Network

    Sevlian, Raffi

    2010-01-01

    This report explores the use of machine learning techniques to accurately predict travel times in city streets and highways using floating car data (location information of user vehicles on a road network). The aim of this report is twofold, first we present a general architecture of solving this problem, then present and evaluate few techniques on real floating car data gathered over a month on a 5 Km highway in New Delhi.

  5. Floating Bodies of Equilibrium. Explicit Solution

    E-print Network

    Franz Wegner

    2006-09-08

    Explicit solutions of the two-dimensional floating body problem (bodies that can float in all positions) for relative density rho different from 1/2 and of the tire track problem (tire tracks of a bicycle, which do not allow to determine, which way the bicycle went) are given, which differ from circles. Starting point is the differential equation given in archive physics/0205059 and Studies in Appl. Math. 111 (2003) 167-183.

  6. Decimal Floating-Point: Algorism for Computers

    Microsoft Academic Search

    Michael F. Cowlishaw; Coventry CV

    2003-01-01

    Decimal arithmetic is the norm in human calculations, and human-centric applications must use a decimal floating-point arithmetic to achieve the same results. Initial benchmarks indicate that some applications spend 50% to 90% of their time in decimal processing, because software decimal arithmetic suffers a 100× to 1000× performance penalty over hardware. The need for decimal floating-point in hardware is urgent.

  7. Motion Projection for Floating Object Detection

    Microsoft Academic Search

    Zhao-Yi Wei; Dah-jye Lee; David Jilk; Robert Schoenberger

    2007-01-01

    Floating mines are a significant threat to the safety of ships in theatres of military or terrorist conflict. Automating mine\\u000a detection is difficult, due to the unpredictable environment and high requirements for robustness and accuracy. In this paper,\\u000a a floating mine detection algorithm using motion analysis methods is proposed. The algorithm aims to locate suspicious regions\\u000a in the scene using

  8. Analysis of floating point operations in microcontrollers

    Microsoft Academic Search

    Aswin Ramakrishnan; James M. Conrad

    2011-01-01

    The purpose of this paper is to identify the advantages of including a floating point hardware \\/ a mathematical co-processor in microcontrollers used for critical floating point operations. Three different microcontrollers are considered: Renesas M16C\\/62P (CISC without FPU), ATMEGA1280 (RISC without MCU) and Renesas RX62N (CISC with FPU). Gauss-Seidel and Jacobi iterations for a system of 2 and 3 variables

  9. Decimal Floating Point for future processors

    Microsoft Academic Search

    Hossam A. H. Fahmy; Tarek ElDeeb; Mahmoud Yousef Hassan; Yasmin Farouk; R. R. Eissa

    2010-01-01

    Many new designs for Decimal Floating Point (DFP) hardware units have been proposed in the last few years. To date, only the IBM POWER6 and POWER7 processors include internal units for decimal floating point processing. We have designed and tested several DFP units including an adder, multiplier, divider, square root, and fused-multiply-add compliant with the IEEE 754-2008 standard. This paper

  10. Probability Analysis for CMOS Floating Gate Faults

    Microsoft Academic Search

    Hua Xue; Chennian Di; Jochen A. G. Jess

    1994-01-01

    The electrical behavior of a floating gate MOS transistor is mask-topology-dependent, i.e. floating on different sites of interconnection may result in different fault behavior. In this paper, we present a net-oriented deterministic approach to compute the probability of different open faults on each net, by taking into account the process defect statistics and mask layout data. The open faults causing

  11. You May Now Open Your Test Tablets...

    ERIC Educational Resources Information Center

    Schaffhauser, Dian

    2012-01-01

    Tony Alpert, chief operating officer for the Smarter Balanced Assessment Consortium (SBAC), ponders whether to allow tablet computers--and particularly iPads--to be used for summative testing online. As Alpert points out, not only would student cheating compromise the validity of the individual student's test event, "worse yet, it could expose…

  12. Orodispersible films and tablets with prednisolone microparticles.

    PubMed

    Brniak, Witold; Ma?lak, Ewelina; Jachowicz, Renata

    2015-07-30

    Orodispersible tablets (ODTs) and orodispersible films (ODFs) are solid oral dosage forms disintegrating or dissolving rapidly when placed in the mouth. One of the main issues related to their preparation is an efficient taste masking of a bitter drug substance. Therefore, the aim of this study was to prepare and evaluate the microparticles intended to mask a bitter taste of the prednisolone and use them in further preparation of two orodispersible dosage forms. Microparticles based on the Eudragit E PO or E 100 as a taste-masking agent were prepared with spray-drying technique. Tablets containing microparticles, co-processed ODT excipient Pharmaburst, and lubricant were directly compressed with single-punch tablet press. Orodispersible films were prepared by casting polymeric solutions of hydroxypropyl methylcellulose containing uniformly dispersed microparticles. Physicochemical properties of microparticles were evaluated, as well as mechanical properties analysis, disintegration time measurements and dissolution tests were performed for prepared dosage forms. Both formulations showed good mechanical resistance while maintaining excellent disintegration properties. The dissolution studies showed good masking properties of microparticles with Eudragit E 100. The amount of prednisolone released during the first minute in phosphate buffer 6.8 was around 0.1%. After incorporation into the orodispersible forms, the amount of released prednisolone increased significantly. It was probably the effect of faster microparticles wetting in orodispersible forms and their partial destruction by compression force during tableting process. PMID:25889975

  13. Using Tablet Technology for University Lectures

    ERIC Educational Resources Information Center

    Chester, Victoria

    2008-01-01

    Tablet PCs provide numerous benefits over traditional electronically projected lectures that use software such as PowerPoint. Flexibility and spontaneity can be achieved by editing or creating notes in real-time. The input pen or stylus is a very useful tool, especially for courses that involve the extensive use of equations or mathematical…

  14. Touch Tablet Surprises: A Preschool Teacher's Story

    ERIC Educational Resources Information Center

    Shifflet, Rena; Toledo, Cheri; Mattoon, Cassandra

    2012-01-01

    A year and a half ago, Rena, Cheri, and Cassandra were introduced to each other by a colleague because they shared an interest in exploring the impact newer technologies have on learning in early childhood classrooms. They meet regularly to share ideas and information on how to incorporate tablets using best practices. Cassandra's preschool…

  15. MEASUREMENT OF BOUNDARIES USING A DIGITIZER TABLET

    EPA Science Inventory

    The perimeter is the most error prone of the primary measurements (length, perimeter and area) made when using a device such as a digitizer tablet to trace profiles on micrographs. o allow for minimization of this error an expression is developed relating the error in the perimet...

  16. 21 CFR 520.531 - Cythioate tablets.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...510.600(c) of this chapter for use of 30-mg tablet. (c) Special considerations. Cythioate is a cholinesterase inhibitor. Do not use this product in animals simultaneously with or within a few days before or after treatment with or...

  17. Graphics Tablet for the BBC Microcomputer.

    ERIC Educational Resources Information Center

    Whale, R.

    1984-01-01

    Describes an inexpensive solution to the problem of transferring pictures onto a television screen using the analog part of the Model "B" BBC Microcomputer. Instruction for building the graphics tablet (which can easily be constructed by secondary students), program listing for required software, and documentation are included. (JN)

  18. Problems of powder flow in tabletting processes

    Microsoft Academic Search

    J. A. Hersey

    1965-01-01

    Summary The flow of non-compacted granules in the tablet machine hopper is discussed with relevance to the unit dose of drug, which is required to be dispensed. The various factors used to describe powder flow such as angle of repose, interparticulate cohesion and friction, flow through apertures, bulk density and die fillability are considered. The effects of humidity and of

  19. Formulation of a extended release tablet containing dexibuprofen.

    PubMed

    Yi, Hong Gi; Chi, Moon Hyuk; Kim, Yong-Il; Woo, Jong Soo; Park, Eun-Seok

    2008-12-01

    Dexibuprofen, or S(+)-ibuprofen, is the pharmacologically effective enantiomer of racemic ibuprofen. Since dexibuprofen has a low melting point, the amorphous form having a high melting point was prepared with the fused solid dispersion method. With the fused solid dispersion of dexibuprofen, immediate release tablets, extended release tablets, and dual release tablets were compressed and their dissolution profiles compared. The dissolution profiles of the extended release and the dual release tablet depended on the amount of used release modulators (PEO 5,000,000). The release profiles of extended release tablets and extended release part of dual release tablets were well fitted to zero-order release model. The correlation coefficient ranged from 0.982 to 0.995. A pharmacokinetic evaluation where healthy volunteers took tablets of DRT-1 (300 mg) once and the reference drug, two tablets of conventional immediate release tablet (Daxfen, 300 mg), with a 6-h interval between them was studied. The 90% confidence interval for the ratio of the logarithmically transformed AUC (0-24 h), Cmax (0-6 h), and Cmax (6-24 h) values of the dual release tablet compared to those of the conventional immediate release tablet were calculated to be between 0.9176 and 1.0007, 0.9240 and 1.1968, and 0.8713 and 1.1414, respectively. When the immediate release tablet was taken two times with a six hour interval between doses it showed a bioequivalent effect to taking the dual release tablet once within 12 h. The Cmax was reached due to the rapid absorption of the immediate release portion of the dual release tablet and the AUC was maintained due to continuous absorption of the extended release portion. PMID:19099235

  20. Stability studies of aspirin-magaldrate double layer tablets.

    PubMed

    al-Gohary, O M; al-Kassas, R S

    2000-04-01

    Accelerated stability testing was performed on aspirin-magaldrate double layer tablets as well as aspirin-maalox marketed double layer tablets (Ascriptin) in order to evaluate the effect of the presence of the alkaline moieties of the antacid (magaldrate and maalox) on the chemical stability of aspirin. The results were compared simultaneously with that obtained from the marketed Aspro plain tablets. The results revealed that the presence of the alkaline moieties in the tested tablets has increased the rate of aspirin decomposition and reduced its shelf-life. This effect was more pronounced for aspirin tablets containing magaldrate antacid. Determination of shelf-lives at 25 degrees C for the prepared and the marketed tablets was carried out using Arrhenius plots and the results showed that they were 35, 34.5 and 13.5 months for Aspro, Ascriptin and aspirin-magaldrate double layer tablets, respectively. The effect of storage for 50 days and at different temperatures, on the crushing strength and the disintegration time of the prepared and the marked tablets showed a slight decrease in the disintegration time and the crushing strength of the tablets as the storage temperature increased. Aspro tablets did not produce the same results. The in vitro release data of the prepared aspirin-magaldrate double layer tablets and the marketed Ascriptin tablets stored for 50 days and at different storage temperatures as well as Aspro tablets stored at 70 degrees C were best fitted to the first-order kinetics model. The release data of Aspro tablets stored at 50 and 60 degrees C for 50 days were best fitted to Higuchi's model. PMID:10812933

  1. Tablets Vision Inspection Approach Using Fourier Descriptors and Support Vector Machines

    Microsoft Academic Search

    Peng Zhao; Shutao Li

    2008-01-01

    In this paper, an efficient approach for tablets vision inspection is proposed, which can detect missing and broken individual tablets in each blister after they are sealed. The images of tablets in blister can be obtained clearly using multi-lights. From these images the regions of tablets are segmented through thresholding method, and the tablets' shape contours are obtained by Canny

  2. Preparation of rapidly disintegrating tablets containing itraconazole solid dispersions.

    PubMed

    Oshima, Takao; Sonoda, Ryoichi; Ohkuma, Moriyuki; Sunada, Hisakazu

    2007-11-01

    The disintegratability of tablets prepared from two types of solid dispersions containing the water-soluble polymer TC-5 and the enteric polymer HP-55 as an excipient were compared. The disintegratability was better in the tablets of solid dispersions containing non-water-soluble HP-55 than those containing TC-5. In consideration of the dissolubility of solid dispersions containing HP-55, the mean diameter of the solid dispersion (coating powder) must be controlled to 120 microm or less, but as this markedly increases the adhesion/aggregation tendency of the particles (angle of repose: 47 degrees ), control of the adhesion/aggregation tendency emerged as another problem. Therefore, surface-modification was performed in a high-speed agitating granulator using 0.1% light anhydrous silicic acid as a surface modifier, and marked improvement in the flowability was observed. This made continuous tableting using a rotary tablet machine possible even with the poorly flowable solid dispersions. Also, in tableting of the solid dispersions, no recrystallization of amorphous itraconazole by the tableting pressure was observed, and the tablets maintained satisfactory dissolubility. Moreover, it was possible to obtain the rapidly disintegrating tablets with very satisfactory properties, i.e., a tablet hardness of 30 N or higher and a disintegration time of 30 s or less, by the addition of croscarmellose as a disintegrant at 2% to the surface-modified solid dispersion and selection of the tableting pressure at 4.5 kN. PMID:17978511

  3. Amoxycillin release from a floating dosage form based on alginates.

    PubMed

    Whitehead, L; Collett, J H; Fell, J T

    2000-12-01

    Floating alginate beads have been prepared from alginate solutions containing either dissolved or suspended amoxycillin. The beads were produced by the dropwise addition of the alginate into calcium chloride solution, followed by removal of the gel beads and freeze drying. Drug release studies showed that beads prepared with the drug in solution provided some sustained release characteristics and that these could be improved by the addition of amylose. In all cases, the drug release was consistent with release of a dissolved solute from a granular or porous matrix. The beads retained their buoyancy when amylose and amoxycillin were incorporated, exhibiting resultant weight values greater than zero after 20 h. Preparation of the beads from alginate solutions containing the drug in suspension allowed higher drug loadings, at the expense of faster release and lower buoyancy. PMID:11163986

  4. Compression-coated tablets of glipizide using hydroxypropylcellulose for zero-order release: in vitro and in vivo evaluation.

    PubMed

    Huang, Haiqin; Wu, Zhenghong; Qi, Xiaole; Zhang, Huiting; Chen, Qin; Xing, Jiayu; Chen, Haiyan; Rui, Yao

    2013-03-25

    Compression coating, which presents some advantages like short manufacturing process and non-solvent residue over liquid coating, has been introduced to the oral administration systems for decades. The purpose of this study was to design a zero-order release of compression-coated tablets using hydroxypropylcellulose (HPC) as the coating layer and glipizide which was solubilized by manufacturing the inclusion complex of ?-cyclodextrin as a model drug. The effects of the weight ratio of drug and the viscosity of HPC on the release profile were investigated by "f2" factor with Glucotrol XL(®). The uptake and erosion study, the correlation coefficient (R) and the exponent (n) were used as indicators to justify drug release mechanism. Bioavailability in vivo was determined by administering the compression-coated tablets to rabbits in contrast with Glucotrol XL(®). It was found that the formulation presented a well zero-order behavior at the weight ratio of drug 11:14 (core:layer) and the combination of HPC-L (8.0 mPa s) and HPC-M (350 mPa s) (8:9), with the "f2" of 66.90. The mechanism for zero-order release of these compression-coated tablets was solvent penetration into the dosage form and drug dissolution from the erosion of the gelled HPC matrix. The parameter AUC0-? of the compression coated tablets and the market tablets were 37,255.93±1474.08 h ng/ml and 43265.40±1015.28 h ng/ml, while the relative bioavailability was 87.66±1.56%. These studies demonstrate that the designed compression-coated tablets may be a promising strategy for peroral controlled release delivery system of water-insoluble drugs. PMID:23370433

  5. Pharmacokinetic comparison of a dextromethorphan-salbutamol combination tablet and a plain dextromethorphan tablet.

    PubMed

    Silvasti, M; Karttunen, P; Happonen, P; Mykkänen, M; Romppanen, T; Tukiainen, H

    1990-06-01

    We compared in this double-blind crossover study the bioavailability of dextromethorphan from a dextromethorphan-salbutamol combination tablet (Redol comp) and from a plain dextromethorphan tablet (Extuson) by determining dextrorphan concentrations after single-dose oral administration in 10 healthy volunteers. The absorption of salbutamol from the combined preparation was also determined. The absorption of dextromethorphan was slightly faster from the plain dextromethorphan preparation. The peak concentration of dextrorphan was achieved at 1.5 h after Extuson and at 2 h after Redol comp (1,053.0 +/- 366.5 ng/ml and 901.5 +/- 210.9 ng/ml, NS). AUC0-12 values of dextrorphan were 4,315.6 +/- 295.0 (ng/ml)h after Extuson and 3,983.8 +/- 205.6 (ng/ml)h after Redol comp (p less than 0.05). Salbutamol was well absorbed from the combined preparation and the peak concentration was achieved at 3 h (6.57 +/- 2.95 ng/ml). Four subjects reported side-effects typical for salbutamol after the combination tablet. No side-effects were reported after the plain dextromethorphan tablet. On the basis of the present study, we conclude that the absorption of dextromethorphan from the preparations tested is almost equal and the dextromethorphan-salbutamol combination can be administered in tablet form for the treatment of cough. PMID:2376428

  6. Floating seal system for rotary devices

    DOEpatents

    Banasiuk, H.A.

    1983-08-23

    This invention relates to a floating seal system for rotary devices to reduce gas leakage around the rotary device in a duct and across the face of the rotary device to an adjacent duct. The peripheral seal bodies are made of resilient material having a generally U-shaped cross section wherein one of the legs is secured to a support member and the other of the legs forms a contacting seal against the rotary device. The legs of the peripheral seal form an extended angle of intersection of about 10[degree] to about 30[degree] in the unloaded condition to provide even sealing forces around the periphery of the rotary device. The peripheral seal extends around the periphery of the support member except where intersected by radial seals which reduce gas leakage across the face of the rotary device and between adjacent duct portions. The radial seal assembly is fabricated from channel bars, the smaller channel bar being secured to the divider of the support member and a larger inverted rigid floating channel bar having its legs freely movable over the legs of the smaller channel bar forming therewith a tubular channel. A resilient flexible tube is positioned within the tubular channel for substantially its full length to reduce gas leakage across the tubular channel. A spacer extends beyond the face of the floating channel near each end of the floating channel a distance to provide desired clearance between the floating channel and the face of the rotary device. 5 figs.

  7. Floating seal system for rotary devices

    DOEpatents

    Banasiuk, Hubert A. (Chicago, IL)

    1983-01-01

    This invention relates to a floating seal system for rotary devices to reduce gas leakage around the rotary device in a duct and across the face of the rotary device to an adjacent duct. The peripheral seal bodies are made of resilient material having a generally U-shaped cross section wherein one of the legs is secured to a support member and the other of the legs forms a contacting seal against the rotary device. The legs of the peripheral seal form an extended angle of intersection of about 10.degree. to about 30.degree. in the unloaded condition to provide even sealing forces around the periphery of the rotary device. The peripheral seal extends around the periphery of the support member except where intersected by radial seals which reduce gas leakage across the face of the rotary device and between adjacent duct portions. The radial seal assembly is fabricated from channel bars, the smaller channel bar being secured to the divider of the support member and a larger inverted rigid floating channel bar having its legs freely movable over the legs of the smaller channel bar forming therewith a tubular channel. A resilient flexible tube is positioned within the tubular channel for substantially its full length to reduce gas leakage across the tubular channel. A spacer extends beyond the face of the floating channel near each end of the floating channel a distance to provide desired clearance between the floating channel and the face of the rotary device.

  8. Biocidal Efficacy of a Flocculating Emergency Water Purification Tablet

    PubMed Central

    Powers, Edmund M.; Hernandez, C.; Boutros, S. N.; Harper, B. G.

    1994-01-01

    Chlor-Floc (CF) emergency water purification tablets were tested for bactericidal, virucidal, and cysticidal efficacy in water at temperatures ranging from 5 to 25°C. The minimal required log reduction was achieved for bacteria, Giardia muris, and rotavirus, but CF did not achieve the required log reduction of poliovirus at any of the temperatures or times investigated. The biocidal properties of the CF tablet were equivalent to if not greater than those of the Globaline iodine tablet, and the CF tablet was a more rapid cysticide under several potential use conditions. Therefore, it is a suitable substitute for iodine tablets for emergency purification of drinking water. Clarification of turbid waters was effective, but filtration through a cloth is necessary to prevent flocculated sediment from entering the canteen. The CF tablets met military requirements for emergency water purification and are safe and acceptable for use by the military. PMID:16349318

  9. 76 FR 53909 - Draft Guidance for Industry on Tablet Scoring: Nomenclature, Labeling, and Data for Evaluation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-30

    ...subdivision for split tablets.\\1...Characteristics of Scored Tablets,'' Pharmacopeial Forum...functional scores on solid oral dosage form products to ensure the...both NDA and ANDA scored tablet products. To...

  10. 75 FR 81617 - Determination That TRANDATE (Labetalol Hydrochloride) Tablets, 300 Milligrams and 400 Milligrams...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-28

    ...That TRANDATE (Labetalol Hydrochloride) Tablets, 300 Milligrams and 400 Milligrams...that TRANDATE (labetalol hydrochloride) tablets, 300 milligrams (mg) and 400 mg, were...TRANDATE (labetalol hydrochloride) tablets, 300 mg and 400 mg, are the...

  11. 21 CFR 520.310 - Caramiphen ethanedisulfonate and ammonium chloride tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Caramiphen ethanedisulfonate and ammonium chloride tablets. 520.310 Section 520.310 Food and...Caramiphen ethanedisulfonate and ammonium chloride tablets. (a) Specifications. Each tablet contains 10 milligrams of 5st caramiphen...

  12. 77 FR 2555 - Determination That PREZISTA (darunavir) Tablets, 300 Milligrams Was Not Withdrawn From Sale for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-18

    ...Determination That PREZISTA (darunavir) Tablets, 300 Milligrams Was Not Withdrawn From...determined that PREZISTA (darunavir) Tablets, 300 milligrams (mg), was not withdrawn...drug applications (ANDAs) for darunavir tablets, 300 mg, if all other legal and...

  13. 21 CFR 520.88g - Amoxicillin trihydrate and clavulanate potassium film-coated tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...trihydrate and clavulanate potassium film-coated tablets. 520.88g Section 520.88g Food and...trihydrate and clavulanate potassium film-coated tablets. (a) Specifications. Each tablet contains amoxicillin trihydrate and...

  14. 21 CFR 520.1805 - Piperazine phosphate with thenium closylate tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...Piperazine phosphate with thenium closylate tablets. 520.1805 Section 520.1805 Food...Piperazine phosphate with thenium closylate tablets. (a) Specifications. Each scored tablet contains the equivalent of 250...

  15. 78 FR 63228 - Determination That PARAFLEX (Chlorzoxazone) Tablets, 250 Milligrams, Was Not Withdrawn From Sale...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-23

    ...Determination That PARAFLEX (Chlorzoxazone) Tablets, 250 Milligrams, Was Not Withdrawn From...determined that PARAFLEX (Chlorzoxazone) Tablets, 250 milligrams (mg), was not withdrawn...ANDAs) for PARAFLEX (Chlorzoxazone) Tablets, 250 mg, if all other legal and...

  16. 77 FR 34063 - Certain Electronic Devices, Including Mobile Phones and Tablet Computers, and Components Thereof...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-08

    ...Devices, Including Mobile Phones and Tablet Computers, and Components Thereof Institution...devices, including mobile phones and tablet computers, and components thereof by...devices, including mobile phones and tablet computers, and components thereof...

  17. 76 FR 19997 - Determination That FENTORA (Fentanyl Citrate) Buccal Tablet, 300 Micrograms, Was Not Withdrawn...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-11

    ...That FENTORA (Fentanyl Citrate) Buccal Tablet, 300 Micrograms, Was Not Withdrawn From...that FENTORA (fentanyl citrate) buccal tablet, 300 micrograms (mcg), was not withdrawn...ANDAs) for fentanyl citrate buccal tablet, 300 mcg, if all other legal and...

  18. 21 CFR 520.310 - Caramiphen ethanedisulfonate and ammonium chloride tablets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...Caramiphen ethanedisulfonate and ammonium chloride tablets. 520.310 Section 520.310 Food and...Caramiphen ethanedisulfonate and ammonium chloride tablets. (a) Specifications. Each tablet contains 10 milligrams of 5st caramiphen...

  19. 76 FR 11488 - Determination That MEGACE (Megestrol Acetate) Tablets and Nine Other Drug Products Were Not...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-02

    ...Determination That MEGACE (Megestrol Acetate) Tablets and Nine Other Drug Products Were Not...amantadine hydrochloride (HCl)) Tablets and ANDA 84-935 for DEXEDRINE (dextroamphetamine sulfate) Tablets in the Federal Register of July...

  20. 75 FR 64310 - Determination That BUSPAR (Buspirone Hydrochloride) Tablets, 10 Milligrams, 15 Milligrams, and 30...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-19

    ...That BUSPAR (Buspirone Hydrochloride) Tablets, 10 Milligrams, 15 Milligrams, and...that BUSPAR (buspirone hydrochloride) Tablets, 10 milligrams (mg), 15 mg, and 30...drug. BUSPAR (buspirone hydrochloride) Tablets, 10 mg, 15 mg, and 30 mg, are...

  1. 77 FR 7583 - Determination That WILPO (phentermine hydrochloride) Tablets, 8 Milligrams, Was Not Withdrawn...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-13

    ...That WILPO (phentermine hydrochloride) Tablets, 8 Milligrams, Was Not Withdrawn From...that WILPO (phentermine hydrochloride) Tablets, 8 Milligrams (mg), was not withdrawn...ANDAs) for phentermine hydrochloride tablets, 8 mg, if all other legal and...

  2. 78 FR 47410 - Certain Wireless Devices, Including Mobile Phones and Tablets Institution of Investigation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-05

    ...Devices, Including Mobile Phones and Tablets Institution of Investigation AGENCY...devices, including mobile phones and tablets by reason of infringement of certain claims...devices, including mobile phones and tablets by reason of infringement of one or...

  3. 78 FR 69856 - Determination That BANZEL (Rufinamide) Tablet, 100 Milligrams, Was Not Withdrawn From Sale for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-21

    ...Determination That BANZEL (Rufinamide) Tablet, 100 Milligrams, Was Not Withdrawn From...determined that BANZEL (rufinamide) tablet, 100 milligrams (mg), was not withdrawn...applications (ANDAs) for rufinamide tablet, 100 mg, if all other legal and...

  4. 21 CFR 520.88g - Amoxicillin trihydrate and clavulanate potassium film-coated tablets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...trihydrate and clavulanate potassium film-coated tablets. 520.88g Section 520.88g Food and...trihydrate and clavulanate potassium film-coated tablets. (a) Specifications. Each tablet contains amoxicillin trihydrate and...

  5. 76 FR 44012 - Determination That NUVIGIL (Armodafinil) Tablets, 100 Milligrams and 200 Milligrams, Were Not...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-22

    ...Determination That NUVIGIL (Armodafinil) Tablets, 100 Milligrams and 200 Milligrams...determined that NUVIGIL (armodafinil) Tablets, 100 milligrams (mg) and 200 mg, were...applications (ANDAs) for armodafinil tablets, 100 mg and 200 mg, if all other...

  6. 75 FR 14444 - Determination That DIDREX (Benzphetamine Hydrochloride) Tablets, 25 Milligrams, Were Not...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-25

    ...DIDREX (Benzphetamine Hydrochloride) Tablets, 25 Milligrams, Were Not Withdrawn From...benzphetamine hydrochloride (HCl)) Tablets, 25 milligrams (mg), were not withdrawn...ANDAs) for benzphetamine HCl 25 mg tablets, if all other legal and regulatory...

  7. 78 FR 40484 - Determination That METADATE ER (Methylphenidate Hydrochloride) Extended-Release Tablet, 10...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-05

    ...Methylphenidate Hydrochloride) Extended-Release Tablet, 10 Milligrams, Was Not Withdrawn From...hydrochloride (HCl)) extended-release tablet, 10 milligrams (mg), was not withdrawn...methylphenidate HCl extended-release tablet, 10 mg, if all other legal and...

  8. 78 FR 40171 - Certain Wireless Devices, Including Mobile Phones and Tablets; Notice Of Receipt of Complaint...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-03

    ...Devices, Including Mobile Phones and Tablets; Notice Of Receipt of Complaint; Solicitation...Devices, Including Mobile Phones and Tablets, DN 2964; the Commission is soliciting...devices, including mobile phones and tablets. The complaint names as respondents...

  9. 77 FR 27078 - Certain Electronic Devices, Including Mobile Phones and Tablet Computers, and Components Thereof...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-08

    ...Devices, Including Mobile Phones and Tablet Computers, and Components Thereof; Notice...Devices, Including Mobile Phones and Tablet Computers, and Components Thereof, DN...devices, including mobile phones and tablet computers, and components thereof....

  10. 77 FR 25720 - Determination That GRIFULVIN V (Griseofulvin Microcrystalline) Tablets, 250 Milligrams, Was Not...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-01

    ...GRIFULVIN V (Griseofulvin Microcrystalline) Tablets, 250 Milligrams, Was Not Withdrawn From...GRIFULVIN V (griseofulvin microcrystalline) tablets, 250 milligrams (mg), was not withdrawn...ANDAs) for griseofulvin microcrystalline tablets, 250 mg, if all other legal and...

  11. 77 FR 12309 - Determination That PHENURONE (Phenacemide) Tablet, 500 Milligrams, Was Not Withdrawn From Sale...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-29

    ...Determination That PHENURONE (Phenacemide) Tablet, 500 Milligrams, Was Not Withdrawn From...determined that PHENURONE (phenacemide) Tablet, 500 milligrams (mg), was not withdrawn...applications (ANDAs) for phenacemide tablet, 500 mg, if all other legal and...

  12. EFFICIENT COMPUTATION OF ENCLOSURES FOR THE EXACT SOLVENTS OF A QUADRATIC MATRIX EQUATION

    Microsoft Academic Search

    BEHNAM HASHEMI; MEHDI DEHGHAN

    2010-01-01

    None of the usual floating point numerical techniques available for solving the quadratic matrix equation AX 2 +BX +C = 0 with square matrices A,B,C and X, can provide an exact solution; they can just obtain approximations to an exact solution. We use interval arithmetic to compute an interval matrix which contains an exact solution to this quadratic matrix equation,

  13. [The liberation of phenylbutazone from tablets].

    PubMed

    Miseta, M; Hoang Hun Manh; Pintye-Hódi, K; Szabó-Révész, P; Selmeczi, B

    1988-10-01

    The liberation of phenylbutazone from tablets prepared by wet granulation was examined. It was found that the solution process can be described by the equation c = cs (l-e-K.t alpha). The influence of the binder concentration and the disintegrant on the liberation rate was also studied. The increase of the Klucel MF concentration accelerated the liberation of the agents. Among the disintegrants Polyplasdone XL and cyclodextrin block polymer turned out to be very good. PMID:3212016

  14. Formulation, characterization and physicochemical evaluation of amoxicillin effervescent tablets

    PubMed Central

    Aslani, Abolfazl; Sharifian, Tahereh

    2014-01-01

    Background: Amoxicillin is a semisynthetic antibiotic, which is used as an antimicrobial drug. This study was designed to formulate amoxicillin effervescent tablets, aimed at improved patient compliance and increased drug stability. Materials and Methods: In this study, nine effervescent tablet formulations were prepared from amoxicillin trihydrate. The effervescent base was comprised of various amounts of citric acid and sodium bicarbonate. Powders and granules were evaluated for their particle size, bulk density, tapped density, compressibility index, Hausner's ratio and angle of repose. The effervescent tablets were then prepared from powders and granules of acceptable quality by direct compression and fusion methods. The tablets were evaluated for weight variation, friability, pH of solution, carbon dioxide (CO2) content, hardness, effervescence time, thickness, assay, content uniformity, water content and equilibrium moisture content. Results: The results indicated better flowability of granules prepared by fusion method as compared with the direct compression. The percent weight variations of tablets were within the acceptable limit of 0.5%. The friability was less than 1% in all formulations. The solution pH of tablets prepared by direct compression and fusion methods ranged from 4.55 to 5.74 and 4.74-5.84, respectively. The CO2 amounts generated by of fusion method tablets were smaller as compared to the direct compression method. The hardness of tablets was 40.66-56 for direct compression method and 60.6-74.6 for fusion method. The tablets produced by the fusion method had a larger thickness and lower water content than tablets produced by direct compression method. Conclusion: Tablets prepared by the fusion method exhibited superior pre- and post-compression characteristics as compared to tablets prepared by direct compression method. PMID:25371866

  15. Comparison of Echinacea alkylamide pharmacokinetics between liquid and tablet preparations

    Microsoft Academic Search

    A. Matthias; R. S. Addison; L. L. Agnew; K. M. Bone; K. Watson; R. P. Lehmann

    2007-01-01

    The relative oral bioavailability of alkylamides from two different Echinacea dosage forms (liquid and tablet) were compared in a small two-way crossover study in humans (n=3). The liquid preparation investigated contained a mixture of Echinacea purpurea root (300mg\\/ml) and Echinacea angustifolia root (200mg\\/ml) extracted in 60% ethanol. The tablet preparation investigated was also a mixture of E. purpurea root (675mg\\/tablet)

  16. Google matrix 1 Google matrix

    E-print Network

    Shepelyansky, Dima

    Google matrix 1 Google matrix A Google matrix is a particular stochastic matrix that is used by Google's PageRank algorithm. The matrix represents a graph with edges representing links between pages. The rank of each page can be generated iteratively from the Google matrix using the power method. However

  17. Google matrix 1 Google matrix

    E-print Network

    Shepelyansky, Dima

    Google matrix 1 Google matrix Fig.1. Google matrix of Wikipedia articles network, written [19]) A Google matrix is a particular stochastic matrix that is used by Google's PageRank algorithm be generated iteratively from the Google matrix using the power method. However, in order for the power method

  18. Chocolate tablet aspects of cytherean Meshkenet Tessera

    NASA Technical Reports Server (NTRS)

    Raitala, J.

    1993-01-01

    Meshkenet Tessera structures were mapped from Magellan data and several resemblances to chocolate tablet boudinage were found. The complex fault sets display polyphase tectonic sequences of a few main deformation phases. Shear and tension have contributed to the areal deformation. Main faults cut the 1600-km long Meshkenet Tessera highland into bar-like blocks which have ridge and groove pattern oriented along or at high angles to the faults. The first approach to the surface block deformation is an assumption of initial parallel shear faulting followed by a chocolate tablet boudinage. Major faults which cut Meshkenet Tessera into rectangular blocks have been active repetitively while two progressive or superposed boudinage set formations have taken place at high angles during the relaxational or flattening type deformation of the area. Chocolate tablet boudinage is caused by a layer-parallel two-dimensional extension resulting in fracturing of the competent layer. Such structures, defined by two sets of boudin neck lines at right angles to each other, have been described by a number of authors. They develop in a flattening type of bulk deformation or during superposed deformation where the rock is elongated in two dimensions parallel to the surface. This is an attempt to describe and understand the formation and development of structures of Meshkenet Tessera which has complicated fault structures.

  19. The Clinical Assessment and Remote Administration Tablet

    PubMed Central

    Turner, Jessica A.; Lane, Susan R.; Bockholt, H. Jeremy; Calhoun, Vince D.

    2011-01-01

    Electronic data capture of case report forms, demographic, neuropsychiatric, or clinical assessments, can vary from scanning hand-written forms into databases to fully electronic systems. Web-based forms can be extremely useful for self-assessment; however, in the case of neuropsychiatric assessments, self-assessment is often not an option. The clinician often must be the person either summarizing or making their best judgment about the subject’s response in order to complete an assessment, and having the clinician turn away to type into a web browser may be disruptive to the flow of the interview. The Mind Research Network has developed a prototype for a software tool for the real-time acquisition and validation of clinical assessments in remote environments. We have developed the clinical assessment and remote administration tablet on a Microsoft Windows PC tablet system, which has been adapted to interact with various data models already in use in several large-scale databases of neuroimaging studies in clinical populations. The tablet has been used successfully to collect and administer clinical assessments in several large-scale studies, so that the correct clinical measures are integrated with the correct imaging and other data. It has proven to be incredibly valuable in confirming that data collection across multiple research groups is performed similarly, quickly, and with accountability for incomplete datasets. We present the overall architecture and an evaluation of its use. PMID:22207845

  20. Floating zone melting of cadmium telluride

    NASA Technical Reports Server (NTRS)

    Chang, Wen-Ming; Regel, L. L.; Wilcox, W. R.

    1992-01-01

    To produce superior crystals of cadmium telluride, floating zone melting in space has been proposed. Techniques required for floating zone melting of cadmium telluride are being developed. We have successfully float-zoned cadmium telluride on earth using square rods. A resistance heater was constructed for forming the molten zone. Evaporation of the molten zone was controlled by adding excess cadmium to the growth ampoule combined with heating of the entire ampoule. An effective method to hold the feed rod was developed. Slow rotation of the growth ampoule was proven experimentally to be necessary to achieve a complete symmetric molten zone. Most of the resultant cylindrical rods were single crystals with twins. Still needed is a suitable automatic method to control the zone length. We tried a fiber optical technique to control the zone length, but experiments showed that application of this technique to automate zone length control is unlikely to be successful.

  1. Deformation of a floating liquid marble.

    PubMed

    Ooi, Chin Hong; Vadivelu, Raja K; St John, James; Dao, Dzung Viet; Nguyen, Nam-Trung

    2015-06-01

    A rigid spherical particle floating on a liquid is a known problem with well-defined solutions. Under the combined effect of gravity and surface tension, the rigid particle deforms the liquid surface. However, in the case of a floating soft particle such as a liquid marble, not only the liquid surface but also the particle itself deforms. In this paper, we investigate the deformation of a floating liquid marble and characterise its height as well as aspect ratio. The experimental results show that theoretical models for a rigid spherical particle suit well for small liquid marbles. Larger marbles require an oblate liquid spheroid model. We will discuss the limitations of the two models and characterise the deformation of these marbles. PMID:25882511

  2. Validated UPLC method for determination of unbound bile acids in colesevelam HCl tablets.

    PubMed

    Vallapragada, Venkata Vivekanand; Inti, Gopichand; Vidiyala, Sudhakar Rao; Jadi, Sreeramulu

    2015-01-01

    A simple, precise and accurate gradient reverse-phase ultra-performance liquid chromatographic method was developed for the quantitative determination of bile acids [glycocholic acid (GCA), glycochenodeoxycholic acid (GCDA) and taurodeoxycholic acid (TDCA)) in in vitro bile acid-binding study of Welchol tablets. The method was developed using Phenomenex Kinetex C18 (50 × 2.10 mm, 1.7 µm) column with mobile phase containing a gradient mixture of solvent A consisting of 0.02 M tetrabutylammonium phosphate (pH 7.5) and solvent B consists acetonitrile. The eluted compounds were monitored at 210 nm and the runtime was within 2 min. The binding parameter constants of Colesevelam HCl tablets 625 mg were determined using the Langmuir approximation at pH 6.8 by UPLC. The method is selective and capable of detecting bile acids in the presence of placebo matrix. The method has been validated with a lower limit of quantitation of 0.01 mM for bile acids. A linear response function was established for the range of concentrations 0.01-30.0 mM (r > 0.99) for GCA, GCDA and TDCA. The intra- and interday precision values for bile acids met the acceptance as per Food and Drug Administrations guidelines. The developed method was applied to in vitro bile acid-binding studies of Colesevelam HCl tablets. PMID:24795077

  3. Capillary electrophoretic assay for the stability of tris(8-quinolinolato)gallium(III) in tablet formulations.

    PubMed

    Foteeva, Lidia S; Stolyarova, Natalya V; Timerbaev, Andrei R; Keppler, Bernhard K

    2008-09-10

    A capillary electrophoresis (CE) method for testing the stability of a novel oral anticancer metallodrug, tris(8-quinolinolato)gallium(III) (KP46), is proposed. As both the intact drug and its eventual impurity or/and decomposition product, 8-quinolinol, are not charged (at most of the pH range), the micellar-mediated CE mode based on using micellar concentrations of sodium dodecyl sulfate was employed. The running electrolyte conditions were optimized in order to resolve the peak of KP46 from the signal of 8-quinolinol, as well as from these of tablet matrix components. The stability of KP46 in different organic and water-organic solvent systems was studied regarding its limited solubility and the following recovering experiments. The method thus developed was applied to the determination of KP46 in tablet formulations, for which sample preparation method, namely powdering and ultrasound-assisted extraction (with 50% aqueous acetone), was tested and optimized in terms of procedure time (10 min). Different in the content of the active substance (10-30%) batches of tablets stored for two years after preparation were validated and recoveries obtained at the level from 97 to 102% confirmed sufficient drug stability. This principal finding was verified by means of an independent method, gas chromatography coupled with mass spectrometry (GC-MS). PMID:18579328

  4. 14 CFR 136.11 - Helicopter floats for over water.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Helicopter floats for over water. 136.11 Section...Air Tour Safety Standards § 136.11 Helicopter floats for over water. (a) A helicopter used in commercial air tours over...

  5. 14 CFR 136.11 - Helicopter floats for over water.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Helicopter floats for over water. 136.11 Section...Air Tour Safety Standards § 136.11 Helicopter floats for over water. (a) A helicopter used in commercial air tours over...

  6. Preparation and evaluation of ketoprofen floating oral delivery system

    Microsoft Academic Search

    A. H. El-Kamel; M. S. Sokar; S. S. Al Gamal; V. F. Naggar

    2001-01-01

    A sustained release system for ketoprofen designed to increase its residence time in the stomach without contact with the mucosa was achieved through the preparation of floating microparticles by the emulsion-solvent diffusion technique. Four different ratios of Eudragit S100 (ES) with Eudragit RL (ERL) were used to form the floating microparticles. The drug retained in the floating microparticles decreased with

  7. Performance Boundaries of Massive Floating Car Data Offloading

    E-print Network

    Fiore, Marco

    Performance Boundaries of Massive Floating Car Data Offloading Silvia Ancona, Razvan Stanica, Marco Bari, Via Edoardo Orabona 4, 70126 Bari, Italy s.ancona@studenti.poliba.it Abstract--Floating Car Data nearly optimal performance under any FCD aggregation model. I. INTRODUCTION The term Floating Car Data

  8. Floating-Point Division and Square Root Implementation using a

    E-print Network

    Draper, Jeff

    Floating-Point Division and Square Root Implementation using a Taylor-Series Expansion Algorithm for floating-point (FP) arithmetic is an essential feature of modern microprocessor design. Although division, they are indispensable and becoming increasingly important in many modern applications. In this paper, a fused floating

  9. Automatic Floating-Point to Fixed-Point Transformations

    E-print Network

    Evans, Brian L.

    Automatic Floating-Point to Fixed-Point Transformations Kyungtae Han, Alex G. Olson, and Brian L processing and communication algorithms are first simulated using floating-point arithmetic and later transformed into fixed-point arithmetic to reduce implementation complexity. For the floating-point to fixed

  10. Control of Free-Floating Humanoid Robots Through Task Prioritization

    E-print Network

    Sentis, Luis

    Control of Free-Floating Humanoid Robots Through Task Prioritization Luis Sentis and Oussama Khatib involving free- floating behaviors. Recently, we presented a prioritized task- oriented control framework's body and environment. We adapt here this framework to the control of free-floating robots. Index Terms

  11. Floating point verification in HOL Light: the exponential function

    E-print Network

    Haddadi, Hamed

    Floating point verification in HOL Light: the exponential function John Harrison \\Lambda University in floating point arithmetic seem good targets for formal verification using a me­ chanical theorem prover. We­checked verification of an algorithm for computing the exponential function in IEEE­754 standard binary floating point

  12. Compact floating-gate true random number generator

    E-print Network

    Maryland at College Park, University of

    Compact floating-gate true random number generator P. Xu, Y.L. Wong, T.K. Horiuchi and P.A. Abshire. Hot-electron injection is used in a floating-gate MOSFET to program the probability. Measurements show compact with less than 20 transistors. We use hot-electron injection in float- ing-gate MOSFETs

  13. NEWTON'S METHOD IN FLOATING POINT ARITHMETIC AND ITERATIVE REFINEMENT OF

    E-print Network

    Tisseur, Francoise

    NEWTON'S METHOD IN FLOATING POINT ARITHMETIC AND ITERATIVE REFINEMENT OF GENERALIZED EIGENVALUE Mathematics Vol. 22, No. 4, pp. 1038­1057 Abstract. We examine the behavior of Newton's method in floating method in floating point arithmetic, allowing for extended precision in computation of the residual

  14. L A T E XParagraphs Floating around Figures Thomas Kneser

    E-print Network

    L A T E X­Paragraphs Floating around Figures Thomas Kneser Gesellschaft f¨ur wissenschaftliche the figures, or -- from another point of view -- figures should `float' in paragraphs. This article presents the L A T E X style option FLOATFIG which can be used to set such Floating Figures as easily as L A T E

  15. A FLOATING BODY APPROACH TO FEFFERMAN'S HYPERSURFACE MEASURE

    E-print Network

    A FLOATING BODY APPROACH TO FEFFERMAN'S HYPERSURFACE MEASURE DAVID E. BARRETT Abstract. The floating body approach to affine surface area is adapted to a holomorphic context providing an alternate hypersurface measure, affine surface area, floating body. 2000 Mathematics Subject Classification: 32T15

  16. Parameterized floating-point logarithm and exponential functions for FPGAs

    E-print Network

    Paris-Sud XI, Université de

    Parameterized floating-point logarithm and exponential functions for FPGAs J´er´emie Detrey Florent, 2005 Abstract As FPGAs are increasingly being used for floating-point computing, the feasi- bility of a library of floating-point elementary functions for FPGAs is discussed. An initial implementation

  17. NEWTON'S METHOD IN FLOATING POINT ARITHMETIC AND ITERATIVE REFINEMENT OF

    E-print Network

    Higham, Nicholas J.

    NEWTON'S METHOD IN FLOATING POINT ARITHMETIC AND ITERATIVE REFINEMENT OF GENERALIZED EIGENVALUE PROBLEMS FRANC¸OISE TISSEUR \\Lambda Abstract. We examine the behaviour of Newton's method in floating point. For added generality we give a detailed analysis of the general Newton method in floating point arithmetic

  18. Floating-Point Division and Square Root Implementation using a

    E-print Network

    Draper, Jeff

    Floating-Point Division and Square Root Implementation using a Taylor-Series Expansion Algorithm Institute Marina del Rey, CA 90292, USA {tjkwon, draper}@ISI.EDU Abstract--Hardware support for floating, they are indispensable and becoming increasingly important in many modern applications. In this paper, a fused floating

  19. Floating Codes for Joint Information Storage in Write Asymmetric Memories

    E-print Network

    Bruck, Jehoshua (Shuki)

    Floating Codes for Joint Information Storage in Write Asymmetric Memories Anxiao (Andrew) Jiang and other non-volatile memories based on floating-gate cells have become a very important family study codes, which we call floating codes, that maximize the total number of times the variables can

  20. External Resource: Why Do Astronauts Float in Space?

    NSDL National Science Digital Library

    1900-01-01

    This NASA video segment explains why objects seem to float in space. Viewers learn that an apple that floats in space is really in a state of freefall. Since the whole space shuttle is also in freefall, the apple seems to float. An animation of a person i

  1. Preparation and in vitro characterization of gellan based floating beads of acetohydroxamic acid for eradication of H. pylori.

    PubMed

    Rajinikanth, Parauvathanahalli Siddalingam; Mishra, Brahmeshwar

    2007-12-01

    Gellan based floating beads of acetohydroxamic acid (AHA) were prepared by the ionotropic gellation method to achieve controlled and sustained drug release for treatment of Helicobacter pylori infection. The prepared beads were evaluated for diameter, surface morphology and encapsulation efficiency. Formulation parameters like concentrations of gellan, chitosan, calcium carbonate and the drug influenced the in vitro drug release characteristics of beads. Drug and polymer interaction studies were carried out using differential scanning calorimetry. Chitosan coating increased encapsulation efficiency of the beads and reduced the initial burst release of the drug from the beads. Kinetic treatment of the drug release data revealed a matrix diffusion mechanism. Prepared floating beads showed good antimicrobial activity (in vitro H. pylori culture) as potent urease inhibitors. In conclusion, an oral dosage form of floating gellan beads containing AHA may form a useful stomach site specific drug delivery system for the treatment of H. pylori infection. PMID:18165186

  2. Quantum Computing with Electrons Floating on Liquid

    E-print Network

    Dykman, Mark

    Quantum Computing with Electrons Floating on Liquid Helium P. M. Platzman1 * and M. I. Dykman2 excited electrons from the surface. There is much interest in constructing analog quantum computers (AQC quantum computation is a more diffi- cult problem because these physical systems must consist

  3. Daphnia (zoomed on floating blood cells)

    NSDL National Science Digital Library

    Katie Hale (CSUF; Biological Sciences)

    2007-07-18

    These pin drops are the clearly defined blood cells of the Daphnia. We are only able to see the cells with use of a microscope. Keep in mind that the cells are not confined in any blood vessel (called an open circulatory system) and freely float throughout the body.

  4. The Accuracy of Floating Point Summation

    Microsoft Academic Search

    Nicholas J. Higham

    1993-01-01

    . The usual recursive summation technique is just one of several ways of computing thesum of n floating point numbers. Five summation methods and their variations are analysed here.The accuracy of the methods is compared using rounding error analysis and numerical experiments.Four of the methods are shown to be special cases of a general class of methods, and an error

  5. Error analysis of floating-point computation

    Microsoft Academic Search

    J. H. Wilkinson

    1960-01-01

    This paper consists of two main sections. In the first the bounds are derived for the rounding errors made in the fundamental floating-point arithmetic operations. In the second, these results are applied in the analysis of a number of computing techniques for the calculation of the eigenvalues of matrices. In each case thecomputed solution is expressed as the exact solution

  6. Robust adaptive floating-point geometric predicates

    Microsoft Academic Search

    Johnathan Richard Shewchuk

    1996-01-01

    Fast C implementations of four geometric predicates, the 2D and 3D orientation and incircle tests, are publicly avail- able. Their inputs are ordinary single or double precision floating-point numbers. They owe their speed to two fea- tures. First, they employ new fast algorithms for arbitrary precision arithmetic that have a strong advantage over other software techniques in computations that manipulate

  7. Adaptive floating search methods in feature selection

    Microsoft Academic Search

    Petr Somol; Pavel Pudil; Jana Novovicová; Pavel Paclík

    1999-01-01

    Abstract A new,suboptimal,search strategy for feature selection is presented. It represents a more,sophisticated version of ‘‘classical’’ floating search algorithms (Pudil et al., 1994), attempts to remove some of their potential deficiencies and facilitates finding a solution even closer to the optimal,one. ” 1999 Elsevier Science B.V. All rights reserved. Keywords: Pattern recognition; Feature selection; Search methods

  8. A New Concept in Floating Production Systems

    Microsoft Academic Search

    M. H. Patel; J. I. Montgomery; M. S. Worley

    1984-01-01

    This paper describes a tandem hull floating production platform which combines the large deck space and high payload carrying advantages of a monohull vessel with some of the low wave induced motion characteristics that are typical of semisubmersible vessels. The basic features of the tandem hull platform are presented and comparisons made with the motion characteristics of various other hull

  9. The salinity of a floating forest

    Microsoft Academic Search

    Wesley Bruce

    2002-01-01

    Joachim Scheven has proposed an interesting theory that the Euro-American coals have not grown in place but formed when a huge forest of floating aquatic plants was swept on shore and buried in the catastrophe of Noah's Flood. Scheven's video 1 and published material 2-5 indicates that the Lepidendron and Sigillaria species of the Carbon- iferous coals were aquatic plants.

  10. End connector for floating oil boom

    Microsoft Academic Search

    Acheson

    1979-01-01

    An end connector for joining with a similar connector to connect two fence sections of a floating oil boom is designed having a central channel and wing so that the wing of one connector is received within the channel of another connector and shoulders to allow for longitudinal movement only, a lock pin movable within a first slot into and

  11. Submerged floating tunnels (SFTs) for Norwegian fjords

    Microsoft Academic Search

    Per Tveit

    2010-01-01

    Submerged floating tunnels (SFTs) weigh roughly the same as the surrounding water. The loads on the tunnel depend on the variation of the forces on the tunnel. The forces come from variation in traffic, current, temperature, waves, weight of water, weight of concrete, growth on the tunnel, wear of asphalt, dust and debris, relaxation of prestress and shrinkage and creep

  12. Floating hydrometer with energy dissipating baffle

    Microsoft Academic Search

    Kownurko

    1987-01-01

    This patent describes a floating hydrometer employable for purposes of obtaining measurements of the presence of suspended solids in a fluid substance contained in a receptacle comprising: a. a probe portion operative as an instrument-bearing housing; b. an elongated tubular element having a hollow interior and at least one open end so as to enable the flow into the hollow

  13. Secure Identification of Free-Floating Planets

    E-print Network

    Cheongho Han

    2006-03-02

    Among the methods proposed to detect extrasolar planets, microlensing is the only technique that can detect free-floating planets. Free-floating planets are detected through the channel of short-duration isolated lensing events. However, if a seemingly isolated planetary event is detected, it is difficult to firmly conclude that the event is caused by a free-floating planet because a wide-separation planet can also produce an isolated event. There were several methods proposed to break the degeneracy between the isolated planetary events produced by the free-floating and wide-separation planets, but they are incomplete. In this paper, we show that free-floating planets can be securely identified by conducting astrometric follow-up observations of isolated events to be detected in future photometric lensing surveys by using high-precision interferometers to be operated contemporarily with the photometric surveys. The method is based on the fact that astrometric lensing effect covers much longer range of the lens-source separation than the photometric effect. We demonstrate that several astrometric follow-up observations of isolated planetary events associated with source stars brighter than $V\\sim 19$ by using the {\\it Space Interferometry Mission} with an exposure time of $\\lesssim 10 {\\rm min}$ for each observation will make it possible to measure the centroid shift induced by primaries with projected separations up to $\\sim 100 {\\rm AU}$. Therefore, the proposed method is far more complete than previously proposed methods that are flawed by the limited applicability only to planets with projected separations $\\lesssim 20 {\\rm AU}$ or planets accompanied by bright primaries.

  14. An efficient multi-tier tablet server storage architecture

    Microsoft Academic Search

    Richard P. Spillane; Pradeep J. Shetty; Erez Zadok; Sagar Dixit; Shrikar Archak

    2011-01-01

    Distributed, structured data stores such as Big Table, HBase, and Cassandra use a cluster of machines, each running a database-like software system called the Tablet Server Storage Layer or TSSL. A TSSL's performance on each node directly impacts the performance of the entire cluster. In this paper we introduce an efficient, scalable, multi-tier storage architecture for tablet servers. Our system

  15. Pore size distribution in tablets measured with a morphological sieve

    Microsoft Academic Search

    Yu San Wu; Lucas J. van Vliet; Henderik W. Frijlink; Kees van der Voort Maarschalk

    2007-01-01

    Porosity and pore structure are important characteristics of tablets, since they influence mechanical strength and many other properties. This paper proposes an alternative method for the characterization of pore structure based on image analysis of SEM micrographs. SEM images were made of sodium chloride tablets made with three different particle sizes. The pore size distribution in these images was determined

  16. The Practice of Splitting Tablets: Cost and Therapeutic Aspects

    Microsoft Academic Search

    John Bachynsky; Cheryl Wiens; Krystal Melnychuk

    2002-01-01

    Background: Tablet splitting is used in pharmacy practice to adjust the dose to be administered. It is also being advocated as a method of reducing prescription drug costs. Methods: The potential for using this practice as a cost-saving method was examined. The top 200 prescription products in Canada were evaluated for their potential for tablet splitting to reduce costs. The

  17. Tableau Economique: Teaching Economics with a Tablet Computer

    ERIC Educational Resources Information Center

    Scott, Robert H., III

    2011-01-01

    The typical method of instruction in economics is chalk and talk. Economics courses often require writing equations and drawing graphs and charts, which are all best done in freehand. Unlike static PowerPoint presentations, tablet computers create dynamic nonlinear presentations. Wireless technology allows professors to write on their tablets and…

  18. Protecting Investments: Third-Party Warranty Coverage for Tablets

    ERIC Educational Resources Information Center

    Sands, Austin

    2012-01-01

    A year ago, only a handful of K-12 schools and universities had integrated tablets into their curricula. Today, not one week passes with out another iPad rollout announcement. The reasons that schools use tablets are as varied as the schools themselves. Hawaii Preparatory Academy uses iPads to encourage budding physicists, linguists, and…

  19. Commentary: Tablet PCs--Lightweights with a Teaching Punch

    ERIC Educational Resources Information Center

    Parslow, Graham R.

    2010-01-01

    Tablet (or slate) computers are a group of small portable computers that have two features in common, a touch screen and wireless connectivity to the web. At the 2010 Consumer Electronics show held in January in Las Vegas, this category of product caused the greatest interest ahead of the release of the Apple iPad (www.cesweb.org). The tablet PC…

  20. The Tablet PC for Faculty: A Pilot Project

    ERIC Educational Resources Information Center

    Weitz, Rob R.; Wachsmuth, Bert; Mirliss, Danielle

    2006-01-01

    This paper describes a pilot project with the purpose of evaluating the usefulness of tablet PCs for university professors. The focus is on the value of tablets primarily with respect to teaching and learning (and not for research or administrative work). Sixty-four professors, distributed across the various schools of a university, were provided…

  1. Tablet PC Technology for the Enhancement of Synchronous Distributed Education

    Microsoft Academic Search

    Elliot Moore II; Tristan T. Utschig; Kevin A. Haas; Benjamin Klein; P. D. Yoder; Ying Zhang; Monson H. Hayes

    2008-01-01

    In this paper, we describe how tablet PCs are being used at Georgia Tech Savannah (GTS) to improve student learning in a distributed classroom environment. The Tablet PC is an attractive technology for use in synchronous distributed learning environments because of its mobility, and its ability to not only serve as an effective note taking device but also as a

  2. Usability Evaluation of Eye Tracking on an Unmodified Common Tablet

    E-print Network

    Oleg, Komogortsev - Department of Computer Science, Texas State University

    devices such as cell phones and tablet PCs are potential candidates for the applica- tionUsability Evaluation of Eye Tracking on an Unmodified Common Tablet Abstract This paper describes the design, implementation, and usability evaluation of a neural network based eye tracking system

  3. Pharmacokinetic comparison of the buprenorphine sublingual liquid and tablet

    Microsoft Academic Search

    Kory J Schuh; Chris-Ellyn Johanson

    1999-01-01

    Buprenorphine is a ? opioid partial agonist being developed as a treatment for opioid dependence. Buprenorphine, usually administered as a sublingual liquid, is now being developed as a sublingual tablet for clinical use. The present study compared participants’ plasma concentrations after daily maintenance on three buprenorphine liquid doses (2, 4 and 8 mg) and one tablet dose (8 mg). Fourteen

  4. Tablet preformulations of indomethacin-loaded mesoporous silicon microparticles.

    PubMed

    Tahvanainen, Maria; Rotko, Tanja; Mäkilä, Ermei; Santos, Hélder A; Neves, Diogo; Laaksonen, Timo; Kallonen, Aki; Hämäläinen, Keijo; Peura, Marko; Serimaa, Ritva; Salonen, Jarno; Hirvonen, Jouni; Peltonen, Leena

    2012-01-17

    In this study, indomethacin-loaded thermally oxidized mesoporous silicon microparticles (TOPSi-IMC) were formulated into tablets with excipients in order to improve the dissolution and permeability properties of the poorly soluble drug. Formulations of TOPSi-IMC particles and excipients were prepared at different TOPSi-IMC particle ratios (25, 30 and 35%). The formulations were compressed by direct compression technique with a single punch tablet machine. For comparison, a formulation containing the bulk IMC (indomethacin) and the same excipients without thermally oxidized mesoporous silicon microparticles particles (TOPSi) was prepared and compressed into tablets. The TOPSi-IMC tablets were characterised according to weight, thickness, crushing strength, disintegration time and dissolution rate. The results of this study show that TOPSi-IMC particles can be compressed to a conventional tablet. The release rate of the drug and its permeation across intestinal cells model (Caco-2) from TOPSi-IMC tablets was improved compared to the bulk IMC tablets. The dissolution rate and permeability of IMC from the tablets decreased with increasing ratio of the TOPSi-IMC particles in the formulation. The phenomenon is, presumably, a result of the loss of unique pore structure of the particles due to deformation of the particles under the compression load. PMID:22063301

  5. POTENTIAL OF CARNUBA WAX IN AMELIORATING BRITTLE FRACTURE DURING TABLETING

    Microsoft Academic Search

    UHUMWANGHO MU; OKOR RS; ADOGAH JT

    Carnuba wax (as binder) forms hard tablets even at low compression load attributable to its high plasticity. The aim of the present study is to investigate its potential in ameliorating brittle fracture (i.e., lamination and capping) a problem often encountered during tableting. Granules of paracetamol (test drug) were made by triturating the drug powder with the melted wax or starch

  6. The Tablet PC classroom: Erasing borders, stimulating activity, enhancing communication

    Microsoft Academic Search

    Judy Sneller

    2007-01-01

    In fall 2006, South Dakota School of Mines & Technology launched a mandatory Tablet PC program for incoming students. As I prepared to teach my first all- tablet class, my reaction was mixed. Although the idea was exciting, facing a sea of computers on each student desk meant leaving my comfort zone and testing new classroom methods. Would this new

  7. Abuse and diversion of buprenorphine sublingual tablets and film.

    PubMed

    Lavonas, Eric J; Severtson, S Geoffrey; Martinez, Erin M; Bucher-Bartelson, Becki; Le Lait, Marie-Claire; Green, Jody L; Murrelle, Lenn E; Cicero, Theodore J; Kurtz, Steven P; Rosenblum, Andrew; Surratt, Hilary L; Dart, Richard C

    2014-07-01

    Buprenorphine abuse is common worldwide. Rates of abuse and diversion of three sublingual buprenorphine formulations (single ingredient tablets; naloxone combination tablets and film) were compared. Data were obtained from the Researched Abuse, Diversion, and Addiction-Related Surveillance (RADARS) System Poison Center, Drug Diversion, Opioid Treatment (OTP), Survey of Key Informants' Patients (SKIP), and College Survey Programs through December 2012. To control for drug availability, event ratios (rates) were calculated quarterly, based on the number of patients filling prescriptions for each formulation ("unique recipients of a dispensed drug," URDD) and averaged and compared using negative binomial regression. Abuse rates in the OTP, SKIP, and College Survey Programs were greatest for single ingredient tablets, and abuse rates in the Poison Center Program and illicit diversion rates were greatest for the combination tablets. Combination film rates were significantly less than rates for either tablet formulation in all programs. No geographic pattern could be discerned. PMID:24680219

  8. Tableting process optimisation with the application of fuzzy models.

    PubMed

    Belic, Ales; Skrjanc, Igor; Bozic, Damjana Zupancic; Vrecer, Franc

    2010-04-15

    A quality-by-design (QbD) principle, including process analytical technology, is becoming the principal idea in drug development and manufacturing. The implementation of QbD into product development and manufacturing requires larger resources, both human and financial, however, large-scale production can be established in a more cost-effective manner and with improved product quality. The objective of the present work was to study the influence of particle size distribution in powder mixture for tableting, and the settings of the compression parameters on the tablet quality described by the capping coefficient, standard deviations of mass and crushing strength of compressed tablets. Fuzzy models were used for modelling of the effects of the particle size distribution and the tableting machine settings on the tablet quality. The results showed that the application of mathematical models, based on the contemporary routinely measured quantities, can significantly improve the trial-and-error procedures. PMID:20096760

  9. Comparison Between Terrestrial Explosion Crater Morphology in Floating Ice and Europan Chaos

    NASA Technical Reports Server (NTRS)

    Billings, S. E.; Kattenhorn, S. A.

    2003-01-01

    Craters created by explosives have been found to serve as valuable analogs to impact craters, within limits. Explosion craters have been created in floating terrestrial ice in experiments related to clearing ice from waterways. Features called chaos occur on the surface of Europa s floating ice shell. Chaos is defined as a region in which the background plains have been disrupted. Common features of chaos include rafted blocks of pre-existing terrain suspended in a matrix of smooth or hummocky material; low surface albedo; and structural control on chaos outline shape by pre-existing lineaments. All published models of chaos formation call on endogenic processes whereby chaos forms through thermal processes. Nonetheless, we note morphological similarities between terrestrial explosion craters and Europan chaos at a range of scales and consider whether some chaos may have formed by impact. We explore these similarities through geologic and morphologic mapping.

  10. Improved stability of OPALMON tablets under humid conditions. III: Application of the rotary vacuum drying method to dry Opalmon tablets.

    PubMed

    Sekiya, Noboru; Abe, Nobutaka; Yamamoto, Masanobu; Takeda, Kazuhisa

    2007-04-01

    In stability studies on moisture-resistant Opalmon tablets in press-through-packages (PTP), which were placed in aluminum bags, we found that the degradation rate of the dextran formulation is faster than that of the lactose formulation. The fast degradation of the dextran formulation is attributed to residual moisture in the package because drying the tablets before packaging suppressed the degradation and there is a good correlation between the stability of the drug and the water-activity of the tablets. Therefore, we developed a new drying method for the tablets, i.e. the rotary vacuum drying method, and investigated the effects of the operating conditions such as heating temperature, rotation speed, and vacuum degree on the drying time, and the appearance of the tablets. Using the rotary vacuum drying method, the tablets were dried over a short time (30 min) on a mass production scale so that the water activity was less than 0.03. Furthermore, the tablets suffered negligible damage such as breaking and chipping during the drying process. These results indicate that the rotary vacuum drying method is useful for drying tablets on mass production scales. PMID:17409545

  11. A Tablet Computer for Young Children? Exploring Its Viability for Early Childhood Education

    ERIC Educational Resources Information Center

    Couse, Leslie J.; Chen, Dora W.

    2010-01-01

    This study explored the viability of tablet computers in early education by investigating preschool children's ease in acclimating to tablet technology and its defectiveness in engaging them to draw. A total of 41 three- to six-year-old children were videotaped while they used the tablets. The study found significant differences in level of tablet…

  12. Inter-tablet coating variability: Residence times in a horizontal pan coater

    Microsoft Academic Search

    Arjun Kalbag; Carl Wassgren; Sai Sumana Penumetcha; José D. Pérez-Ramos

    2008-01-01

    This paper investigates inter-tablet coating variability, specifically, tablet residence times within the spray zone. Discrete element method computer simulations, experiments, and analytical investigations are performed to measure the residence time per pass, the circulation time, and appearance frequency of spherical shaped tablets for a range of pan speeds and tablet loads. In addition, the fractional residence time, defined as the

  13. Mechanical and PhysicoChemical Characterization of Excipients in Order to Define their Applicability for Tableting

    Microsoft Academic Search

    Katharina Maria Picker

    Aim of the process of tablet production always was to formulate tablets which are as robust and stable as possible. Therefore the main excipients, mainly the fillers, are expected to deform plastically. However during the process of tablet production not only the excipients are deformed but the tableted product deforms also. This can lead to the total or partial damage

  14. Development of new shaped punch to predict scale-up issue in tableting process.

    PubMed

    Aoki, Shigeru; Uchiyama, Jumpei; Ito, Manabu

    2014-01-01

    Scale-up issues in the tableting process, such as capping, sticking, or differences in tablet thickness, are often observed at the commercial production scale. A new shaped punch, named the size adjusted for scale-up (SAS) punch, was created to estimate scale-up issues seen between laboratory scale and commercial scale tableting processes. The SAS punch's head shape was designed to replicate the total compression time of a laboratory tableting machine to that of a commercial tableting machine. Three different lubricated blends were compressed into tablets using a laboratory tableting machine equipped with SAS punches, and any differences in tablet thickness or capping phenomenon were observed. It was found that the new shaped punch could be used to replicate scale-up issues observed in the commercial tableting machine. The SAS punch was shown to be a useful tool to estimate scale-up issues in the tableting process. PMID:24218176

  15. Modulation of tramadol release from a hydrophobic matrix: implications of formulations and processing variables.

    PubMed

    Sudha, B S; Sridhar, B K; Srinatha, A

    2010-03-01

    In the present investigation, hydrogenated cottonseed oil (HCSO) was evaluated as a sustained release matrix for a freely soluble drug, tramadol. Hydrophobic matrix tablets of tramadol, was evaluated by compression of physical mixture of drug and wax, dispersion of drug in HCSO by hot fusion or solubilisation techniques. The method of preparation of tablet had a significant effect on drug release with higher release observed from direct compression matrices and slower release from matrix prepared by dispersion (hot-fused matrices). Influence of addition of hydroxypropylmethyl cellulose, sodium carboxymethyl cellulose, polyethylene glycol 4000 and surfactants like sodium lauryl sulphate and polysorbate 20 to HCSO matrix on drug release was investigated. The added excipients exhibited a propensity to enhance drug release from the HCSO matrix. NaCMC was effective at a lower ratio (<10% w/w) and when incorporated at higher level made HCSO matrix to erode and disintegrate in a short period. PMID:20300896

  16. A new concept in floating production systems

    SciTech Connect

    Patel, M.H.; Montgomery, J.I.; Worley, M.S.

    1984-10-01

    This paper describes a tandem hull floating production platform which combines the large deck space and high payload carrying advantages of a monohull vessel with some of the low wave induced motion characteristics that are typical of semisubmersible vessels. The basic features of the tandem hull platform are presented and comparisons made with the motion characteristics of various other hull forms. The model tests and computer simulation programs used in the design of the tandem hull platform are described and the results presented. Assessments are made of the capital and operating costs of a tandem hull production system and comparisons made with those of other floating production systems that are based on alternative hull forms.

  17. Computer-controlled float zone crystal growth

    NASA Technical Reports Server (NTRS)

    Chan, Y. T.; Mailloux, P. A.

    1993-01-01

    A PC-based computer control system to automate a high-temperature float zone growth of titanium carbide is reported. The control strategy of the computer control system relies on the relations derived from a combination of empirical relations and results from detailed mathematical analysis of the physical transports of the entire float zone assembly. A system control computer program was written to establish real-time determination of the size of the molten zone from a thermal image, control parameters from established relationships, and collected processed data to achieve control objectives. We found that the developed computer control allows the growth process to be operated nearer the stability limit. Any slight variations in growth conditions can be corrected in time to avoid any instability growth, which otherwise cannot be adjusted via manual control.

  18. Sparse Matrix-Vector multiplication on FPGAs

    Microsoft Academic Search

    Ling Zhuo; Viktor K. Prasanna

    2005-01-01

    Floating-point Sparse Matrix-Vector Multiplication (SpMXV) is a key computational kernel in scientific and engineering applications. The poor data locality of sparse matrices significantly reduces the performance of SpMXV on general-purpose processors, which rely heavily on the cache hierarchy to achieve high performance. The abundant hardware resources on current FPGAs provide new opportunities to improve the performance of SpMXV. In this

  19. Comparison of Echinacea alkylamide pharmacokinetics between liquid and tablet preparations.

    PubMed

    Matthias, A; Addison, R S; Agnew, L L; Bone, K M; Watson, K; Lehmann, R P

    2007-09-01

    The relative oral bioavailability of alkylamides from two different Echinacea dosage forms (liquid and tablet) were compared in a small two-way crossover study in humans (n=3). The liquid preparation investigated contained a mixture of Echinacea purpurea root (300 mg/ml) and Echinacea angustifolia root (200 mg/ml) extracted in 60% ethanol. The tablet preparation investigated was also a mixture of E. purpurea root (675 mg/tablet) and E. angustifolia root (600 mg/tablet), but was prepared from the dried 60% ethanolic extracts of these two Echinacea species. Alkylamides were found to be rapidly absorbed and measurable in plasma from both preparations. No significant differences in the tetraene alkylamide pharmacokinetic parameters for T(1/2), AUC(t-lin) and C(max) in the two different preparations were found. T(max) increased from 20 min for the liquid to 30 min for the tablet, which is not unexpected as the tablet required time for disintegration before absorption could occur. These results suggested that there was no significant difference in the bioavailability of alkylamides from the liquid and tablet Echinacea formulations. Furthermore, the results also indicated that the absorption site and any alkylamide loss due to digestive processes were similar in both preparations. PMID:17289362

  20. Evaluation of hexagonal boron nitride as a new tablet lubricant.

    PubMed

    Turkoglu, Murat; Sahin, Inan; San, Tangul

    2005-01-01

    In this study, hexagonal boron nitride (HBN) was evaluated as a new lubricant for pharmaceutical tablet manufacturing. The other conventional lubricants such as magnesium stearate (MGST), stearic acid (STAC), and glyceryl behenate (COMP) were also tested along with HBN. Tablets were manufactured on an instrumented single-station tablet press to monitor and quantify the lower punch ejection force (LPEF). The force ratio, tablet crushing strength, disintegration time, and thickness were measured. The lubricant film formation and lubricant distribution in tablets were studied using the scanning electron microscopy (SEM) and electron probe micro analyzer (EPMA). Based on the force ratio, a good lubrication was obtained at 1% for MGST and HBN; in contrast, STAC and COMP did not show a good lubrication. After 1%, all lubricants performed well. MGST was found to be the most effective lubricant based on LPEF-lubricant concentration profile. HBN provided a 50% decrease in LPEF at 2% lubricant concentration and was rated as an effective tablet lubricant. HBN was better than either STAC or COMP. Unlike MGST, HBN had no significant prolongation effect on tablet disintegration times. PMID:16176018

  1. Tablets containing drug-loaded polymeric nanocapsules: an innovative platform.

    PubMed

    Friedrich, R B; Bastos, M O; Fontana, M C; Ourique, A F; Beck, R C R

    2010-09-01

    The aim of the present work was to evaluate the feasibility to convert drug-loaded nanocapsule suspensions in a solid dosage form (tablets). Dexamethasone was used as a model drug due to its low aqueous solubility and fast drug release from conventional tablets. Granules containing dexamethasone-loaded nanocapsules were obtained by a wet granulation process using a dispersion of polyvinylpirrolidone/nanocapsules as a binder system. Granules were compressed in an eccentric compression machine (D-NC-T). A control formulation (tablets without nanocapsules) was also prepared (D-T). Tablets were characterized by means of mean weight, hardness, friability, diameter, thickness, disintegration time, drug content, morphological analysis by scanning electron microscopy (SEM), and in vitro drug release studies. D-NC-T showed adequate physicochemical characteristics according to the pharmacopeial requirements in terms of mean weight, hardness, friability, disintegration time and drug content. Intact nanocapsules in tablets were observed by SEM. In vitro drug release studies showed a slower release of dexamethasone from these tablets (D-NC-T) compared to the control formulation (D-T). Results showed that these tablets represent an interesting platform to the development of oral drug delivery systems containing polymeric nanocapsules. PMID:21133121

  2. Studies on the development of rapidly disintegrating hyoscine butylbromide tablets.

    PubMed

    Khattab, I S; Zaghloul1, A A; Afouna, M I

    2007-08-01

    The objective of this study was to prepare hyoscine butylbromide (a drug with bitter taste) tablets that can rapidly disintegrate in saliva. The granules were prepared by the extrusion method using aminoalkyl methacrylate copolymers (Eudragit E-100). The drugs dissolved rapidly in medium at pH 1.2 in a dissolution test while none of the drugs dissolved from the granules (% of dissolved < 5%) even after 8 h at pH 6.8. Rapidly disintegrating tablets were prepared using prepared taste-masked granules and a mixture of excipients consisting of crystalline cellulose (Avicel PH-102) and low substituted hydroxypropylcellulose (L-HPC, LH-11).The granules and excipients were mixed well (mixingratio by weight, crystalline cellulose: L-HPC, was 8:2) with 1% magnesium stearate as a lubricant and subsequently compressed at 500-1,500 kgf in a single-punch tableting machine. The prepared tablets (compressed at 500 kgf) containing the taste-masked granules have significant strength (crushing strength was 3.5 kg), and a rapid disintegration time (within 30 sec) was observed in the saliva of healthy volunteers. None of the volunteers sensed any bitter taste after the disintegration of the tablet that contained the taste-masked granules. The results confirmed that rapidly disintegrating tablets can be prepared using these taste-masked granules and excipients that are commonly used in tablet preparation. PMID:22504365

  3. Influence of compression pressure and velocity on tablet sticking.

    PubMed

    Kakimi, Kazuyuki; Niwa, Toshiyuki; Danjo, Kazumi

    2010-12-01

    A rotary tablet machine fitted with 8-mm diameter flat-faced punches was used to measure scraper pressure (SCR), a type of shear stress, to evaluate sticking behavior. The shear stress between the surfaces of the tablet and lower punch was determined using an SCR detection system. Mean surface roughness (R(a)) of tablets, measured by a scanning laser-microscope, was used to estimate the magnitude of sticking. Tablet tensile strength tended to increase with compression pressure at either of the tablet production velocities tested, which was consistent with previous reports. SCR decreased with increasing compression pressure for samples at all compression velocities, and showed a tendency to increase with binder concentration. SCR also tended to increase with compression velocity for samples at all compression pressures, suggesting that the frequency of tablet sticking increased as compression velocity increased. R(a) associated with sticking increased with SCR, indicating that the adhesive force between the particles of the tablet surface and the lower punch surface plays an important role in sticking. PMID:21139255

  4. An Autozeroing Floating-Gate Amplifier

    Microsoft Academic Search

    Paul Hasler; Bradley A. Minch; Chris Diorio

    2001-01-01

    We have developed a bandpass floating-gate amplifier that uses tunneling and pFET hot-electron injection to set its dc operating point adaptively. Because the hot-electron injection is an inherent part of the pFET's behavior, we obtain this adaptation with no additional circuitry. Because the gate currents are small, the circuit exhibits a high-pass characteristic with a cutoff frequency less than 1

  5. Free-floating atmospheric pressure ball plasmas

    Microsoft Academic Search

    G. A. Wurden; C. Ticos; Z. Wang; C. J. V. Wurden

    2007-01-01

    A long-lived (0.3 second, 10-20 cm diameter) ball plasma floating in the air above a water surface has been formed and studied in the laboratory. A 0.4 - 1 mF capacitor is charged to 4-5 kV, and subsequently discharged (30-60 Amps, 20-50 msec duration) into central copper cathode held fixed just below the surface of a bucket of water (with

  6. Fast Decimal Floating-Point Division

    Microsoft Academic Search

    Hooman Nikmehr; Braden Phillips; Cheng-chew Lim

    2006-01-01

    Abstract—A new implementation for decimal floating-point (DFP) division is introduced. The algorithm is based on high-radix SRT division, with the recurrence in a new decimal signed-digit format. Quotient digits are selected using comparison multiples, where the magnitude of the quotient digit is calculated by comparing the truncated partial remainder with limited precision multiples of the divisor. The sign is determined

  7. Floating Ice: Grades K-1: Electronic Book

    NSDL National Science Digital Library

    Jessica Fries-Gaither

    This informational text discusses the unique property of ice - that it floats in liquid water. Students focus on real-world examples and how ice is necessary for life in the polar regions. The text is written at a kindergarten through grade one reading level. This is an onscreen version that contains recorded narration allowing students to listen to the text as they read along. Highlighted vocabulary words have individually recorded definitions heard by clicking on the links.

  8. Floating Ice: Grades K-1: Illustrated Book

    NSDL National Science Digital Library

    Jessica Fries-Gaither

    This informational text discusses the unique property of ice - that it floats in liquid water. Students focus on real-world examples and how ice is necessary for life in the polar regions. The text is written at a kindergarten through grade one reading level. This version is a full-color PDF that can be printed, cut and folded to form a book. Each book contains color photographs and illustrations.

  9. Finite Element Analysis of a Floating Microstimulator

    PubMed Central

    Sahin, Mesut; Ur-Rahman, Syed S.

    2011-01-01

    Analytical solutions for voltage fields in a volume conductor are available only for ideal electrodes with radially symmetric contacts and infinitely extending substrates. Practical electrodes for neural stimulation may have asymmetric contacts and finite substrate dimensions and hence deviate from the ideal geometries. For instance, it needs to be determined if the analytical solutions are adequate for simulations of narrow shank electrodes where the substrate width is comparable to the size of the contacts. As an extension to this problem, a “floating” stimulator can be envisioned where the substrate would be finite in all directions. The question then becomes how small this floating stimulator can be made before its stimulation strength is compromised by the decrease in the medium impedance between the contacts as the contacts are approaching each other. We used finite element modeling to solve the voltage and current profiles generated by these radially asymmetric electrode geometries in a volume conductor. The simulation results suggest that both the substrate size and the bipolar contact separation influence the voltage field when these parameters are as small as a few times the contact size. Both of these effects are larger for increasing elevations from the contact surface, and even stronger for floating electrodes (finite substrate in all directions) than the shank-type electrodes. Location of the contacts on the floating electrode also plays a role in determining the voltage field. The voltage field for any device size and current, and any specific resistance of the volume conductor can be predicted from these results so long as the aspect ratios are preserved. PMID:17601192

  10. IEEE Standard unifies arithmetic model Floating points

    E-print Network

    Beron-Vera, Francisco Javier

    -point number system. Some were binary; some were decimal. There was even a Russian computer that used trinary floating-point system with only three bits each for f and e. Between 2e and 2e+1 the numbers are equally between 1 and 2 in our toy system is 2-3 , or 1 /8. In the full IEEE system, this spacing is 2-52 . MATLAB

  11. Float pump offshore wave energy converters

    SciTech Connect

    Nielsen, K. [Danish Wave Power Aps, Virum (Denmark)

    1996-12-31

    This paper will describe the numerical design models developed by DWP and ES-Consult as part of the Off-shore Wave Energy Converter project OWEC-1 supported by the European Union under the JOULE initiative. Offshore Wave Power Plants composed of float pump systems, has been investigated. Modeling techniques required to provide reliable methods for the predicted hydrodynamic behavior of the floats, their performance has been assessed and standardized criteria and techniques for the design has been provided. The systems investigated and the numerical time domain models developed will be described. The DWP/ES-Consult design models include both heave and surge motion of the device motion. The hydrodynamics are based on the long wave approximation of wave exiting forces as well as nonlinear drag and lift-forces, limits for the buoyancy force and variation of added mass with submergence are included in the calculations. The numerical models developed by DWP/ES-Consult are intended as tools for the structural design. The results in medium waves are compared to more exact hydrodynamic models (heave only) developed at Chalmars University and at NTH norwegian Technical University. Results are compared to model tests and real sea measurements. The design of the float geometry`s and power takeoff has not been optimized. The scope has been to compare and provide tools and guidelines for time domain modeling of offshore wave energy converters as a basis for further optimization.

  12. Capillary induced buckling of floating sheets

    NASA Astrophysics Data System (ADS)

    Pineirua, Miguel; Bico, Jose; Roman, Benoit; Menon, Narayanan

    2012-02-01

    When a water droplet is deposited over a thin floating sheet, radial wrinkles appear in the vicinity of the droplet as a result of capillary forces exerted at the contact line [1]. However, determining the stress state at the contact line is still challenging and limits the full description of the wrinkling pattern. In order to avoid this contact line ambiguities, we propose the experimental study of the buckling of a macroscopic annulus floating on the surface of water and submitted to a difference in surface tension between its inner and outer edges. This particular configuration allows to generate radial wrinkles on the membrane with well defined border conditions. The topography of the wrinkled patterns are precisely measured using a synthetic Schlieren technique. Based on the standard buckling theory, we develop scaling laws for the buckling threshold of the annulus as well as for the wave length and radial extension of the wrinkles, which are compared to our experimental results and numerical simulations. [4pt] [1] J. Huang, M. Juszkiewicz, W.H. de Jeu, E. Cerda, T. Emrick, N. Menon, and T.P. Russell. Capillary wrinkling of floating thin polymer films. Science, 317(5838):650-653, 2007.

  13. FPP [Floating Potential Probe] Results, Final Report

    NASA Technical Reports Server (NTRS)

    Ferguson, Dale C.

    2007-01-01

    The Floating Potential Probe (FPP) operated on the International Space Station (ISS) from December 2000 to April 2001. During that time, it took many measurements of the ISS floating potential and the electron density and temperature. Those measurements were used as inputs to the Environments WorkBench (EWB) model of ISS potentials (originally developed by SAIC, but now sometimes called the Boeing model) that is used even today to predict charging levels for ISS. FPP is now completely defunct, having been removed and ejected from ISS. With the advent of the new Floating Potential Monitoring Unit (FPMU) on ISS, and the beginning of ISS operations with two large solar array panels instead of just one, a review of FPP measurements can offer comparisons with the new FPMU data and perhaps improve the accuracy of future ISS charging predictions. In particular, FPP measurements during times of low electron temperature and high electron density (the times of worst ISS charging) will be brought forward for comparison with the newly obtained FPMU data.

  14. Floating boom performance under waves and currents.

    PubMed

    Castro, A; Iglesias, G; Carballo, R; Fraguela, J A

    2010-02-15

    Floating booms constitute a fundamental tool for the protection of marine and coastal ecosystems against accidental oil spills. Their containment performances in exposed areas are often impaired by the action of waves, currents and winds in a manner which is dependent on the boom's response as a floating body, and which is not fully understood at present. In this work the relationship between the design parameters of a floating boom section and its efficiency against the mode of failure by drainage under a variety of wave and current combinations is investigated by means of physical modelling. Seven boom models with different geometries and buoyancy-weight ratios are tested with an experimental setup that allows them to have and rotate freely. The model displacements under waves (both regular and irregular) and currents, as well as those of the free surface adjacent to the model, are measured with a Computer Vision system developed ad hoc. Two efficiency parameters are defined-the significant and minimum effective boom drafts-and applied to the results of an experimental campaign involving 315 laboratory tests. Thus, the manner in which the design parameters influence the boom's efficiency under different wave and current conditions is established. PMID:19800166

  15. Floating debris in the Mediterranean Sea.

    PubMed

    Suaria, Giuseppe; Aliani, Stefano

    2014-09-15

    Results from the first large-scale survey of floating natural (NMD) and anthropogenic (AMD) debris (>2 cm) in the central and western part of the Mediterranean Sea are reported. Floating debris was found throughout the entire study area with densities ranging from 0 to 194.6 items/km(2) and mean abundances of 24.9 AMD items/km(2) and 6.9 NMD items/km(2) across all surveyed locations. On the whole, 78% of all sighted objects were of anthropogenic origin, 95.6% of which were petrochemical derivatives (i.e. plastic and styrofoam). Maximum AMD densities (>52 items/km(2)) were found in the Adriatic Sea and in the Algerian basin, while the lowest densities (<6.3 items/km(2)) were observed in the Central Tyrrhenian and in the Sicilian Sea. All the other areas had mean densities ranging from 10.9 to 30.7 items/km(2). According to our calculations, more than 62 million macro-litter items are currently floating on the surface of the whole Mediterranean basin. PMID:25127501

  16. The 3-D model: Comparison of parameters obtained from and by simulating different tableting machines

    Microsoft Academic Search

    Katharina M. Picker

    2003-01-01

    The aim of this study is to apply 3-D modeling to data obtained from different tableting machines and for different compression\\u000a wheels on a linear rotary tableting machine replicator. A new analysis technique to interpret these data by 3-D parameter\\u000a plots is presented. Tablets were produced on an instrumented eccentric tableting machine and on a linear rotary tableting\\u000a machine replicator.

  17. An insight into the process of tablet formation of microcrystalline cellulose

    Microsoft Academic Search

    Katharina M. Picker-Freyer

    2007-01-01

    The present paper aims to show whether the shrinking of the microcrystalline cellulose (MCC) tablets can be derived from underlying\\u000a processes and whether these processes can be visualized on a nanoscale level. Tableting of MCC was performed on an instrumented\\u000a eccentric tableting machine to a maximum relative density (?rel,max) of 0.90 of the tablets. The apparent density of the tablets

  18. Tablet use in schools: A critical review of the evidence for learning outcomes

    E-print Network

    Haßler, B.; Major, L.; Hennessy, S.

    2015-01-01

    beyond exploration towards systematic and in-depth investigations building on the existing findings documented here. Keywords tablets; schools; systematic review; iPad; Android; learning outcomes Tablet use in schools: A critical review... been sold worldwide (Ozok et al., 2008). With the launch of the first Google Android-based tablets (2009) and the Apple iPad (2010), the popularity of tablets increased (Geyer & Felske, 2011). Sales of tablets have grown greatly since then...

  19. Float processing of high-temperature complex silicate glasses and float baths used for same

    NASA Technical Reports Server (NTRS)

    Cooper, Reid Franklin (Inventor); Cook, Glen Bennett (Inventor)

    2000-01-01

    A float glass process for production of high melting temperature glasses utilizes a binary metal alloy bath having the combined properties of a low melting point, low reactivity with oxygen, low vapor pressure, and minimal reactivity with the silicate glasses being formed. The metal alloy of the float medium is exothermic with a solvent metal that does not readily form an oxide. The vapor pressure of both components in the alloy is low enough to prevent deleterious vapor deposition, and there is minimal chemical and interdiffusive interaction of either component with silicate glasses under the float processing conditions. Alloys having the desired combination of properties include compositions in which gold, silver or copper is the solvent metal and silicon, germanium or tin is the solute, preferably in eutectic or near-eutectic compositions.

  20. Floating Oil-Spill Containment Device

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.

    2012-01-01

    Previous oil containment booms have an open top that allows natural gas to escape, and have significant oil leakage due to wave action. Also, a subsea pyramid oil trap exists, but cannot move relative to moving oil plumes from deepsea oil leaks. The solution is to have large, moveable oil traps. One version floats on the sea surface and has a flexible tarp cover and a lower weighted skirt to completely entrap the floating oil and natural gas. The device must have at least three sides with boats pulling at each apex, and sonar or other system to track the slowly moving oil plume, so that the boats can properly locate the booms. The oil trap device must also have a means for removal of the oil and the natural gas. A second design version has a flexible pyramid cover that is attached by lines to ballast on the ocean floor. This is similar to fixed, metal pyramid oil capture devices in the Santa Barbara Channel off the coast of California. The ballast lines for the improved design, however, would have winches that can move the pyramid to always be located above the oil and gas plume. A third design is a combination of the first two. It uses a submerged pyramid to trap oil, but has no anchor and uses boats to locate the trap. It has ballast weights located along the bottom of the tarp and/or at the corners of the trap. The improved floating oil-spill containment device has a large floating boom and weighted skirt surrounding the oil and gas entrapment area. The device is triangular (or more than three sides) and has a flexible tarp cover with a raised gas vent area. Boats pull on the apex of the triangles to maintain tension and to allow the device to move to optimum locations to trap oil and gas. The gas is retrieved from a higher buoyant part of the tarp, and oil is retrieved from the floating oil layer contained in the device. These devices can be operated in relatively severe weather, since waves will break over the devices without causing oil leaking. Also, natural gas is entrapped and can be retrieved. All designs can use sonar to locate the moving oil plume, and then be relocated by using boats or winches to move the oil trapping devices. These devices can be constructed of treated, non-permeable DuPont Kevlar cloth (or similar material).