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1

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

PubMed Central

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

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

2011-01-01

2

Polymers derived from Xanthomonas campesteris and Cyamopsis tetragonolobus used as retardant materials for the formulation of sustained release floating matrix tablet of atenolol.  

PubMed

The objective of the present study was to develop, optimize, in vitro, and in vivo evaluation of floating matrix tablet of atenolol using polymer blend derived from Xanthomonas campesteris and Cyamopsis tetragonolobus that are characterized by release requirements of sustained-release product and to improve the oral bioavailability of the drug. A 3(2) full factorial design was employed to optimize the tablets, where content of polymer blend (X1) and ratio of xanthan gum-to-guar gum (X2) were considered as independent variables. The effects of independent variables on dependent variables, i.e. floating time, diffusion exponent, and time to release 50% of atenolol were evaluated. The in vivo pharmacokinetic parameters of the optimized formulation were compared with the marketed sustained release formulation of atenolol (Aten(®)). The optimized formulation containing 20% (w/w) of polymer blend and 50:50 ratio of xanthan gum-to-guar gum was able to float more than 12h and showed the desired sustained drug release from the tablets. In vivo retention studies in rabbit stomach showed the gastric residence of tablet up to 6h. The in vivo study of optimized tablets illustrated significant improvement in the oral bioavailability of atenolol in rabbits. It can be concluded that floating matrix tablet of atenolol prepared by using xanthan gum and guar gum has potential for sustained release of the drug as well as improved oral bioavailability through enhanced gastric residence time of formulation in stomach. PMID:24472506

Dey, Sanjay; Mazumder, Bhaskar; Chattopadhyay, Sankha; Das, Malay Kanti; Sinha, Samarendu; Ganguly, Shantanu; De, Kakali; Mishra, Mridula

2014-04-01

3

Preparation and pharmacokinetics study on gastro-floating sustained-release tablets of troxipide.  

PubMed

Abstract The purpose of this research aimed at preparing gastro-floating sustained-release tablets of troxipide and a further study on in vitro release and in vivo bioavailability. Under the circumstances of direct powder compression, the floating tablets were successfully prepared with HPMC as main matrix material, Carbopol as assistant matrix material, octadecanol as floating agent and sodium bicarbonate as foaming agent to float by gas-forming. The floating time and accumulative release amount as evaluation indexes were utilized to perform pre-experiment screening and single-factor test, respectively, while central composite design response surface method was applied for formulation optimization, followed by in vivo pharmacokinetic study in beagles after oral administration for floating tablets and commercial tablets used as the control. The results indicated that the floating sustained-release tablets held a better capability for floating and drug release and more satisfactory pharmacokinetic parameters, such as a lower Cmax, a prolonged Tmax, but an equivalent bioavailability calculated by AUC0-24 compared to commercial tablets. So a conclusion was finally drawn that the floating sustained-release tablets possessing a good release property could be suitable for demands of design. PMID:25190152

Gao, Yunyun; Gao, Yang; Yin, Fei; Wang, Mi; Wang, Zhenhong; Ye, Tiantian; Yang, Yonggang; Pan, W S; Yang, Xinggang

2014-09-01

4

Gastro-floating tablets of cephalexin: preparation and in vitro/in vivo evaluation.  

PubMed

Gastro-floating tablets of cephalexin were developed to prolong the residence time in major absorption sites. Gastro-floating tablets were prepared and optimized using hydroxypropyl methylcellulose (HPMC K100M) as matrix and sodium bicarbonate as a gas-forming agent. The properties of the tablets in terms of floating lag time, floating time and in vitro release were evaluated. Furthermore, in vivo pharmacokinetic study in fed and fasted beagle dogs was performed. The gastro-floating tablets had short floating lag time and exhibited a satisfactory sustained-release profile in vitro. Compared with conventional capsules, the gastro-floating tablets presented a sustained-release behavior with a relative bioavailability of 99.4%, while the reference sustained-release tablets gave a relative bioavailability of only 39.3%. Meanwhile, the food had significant effect on the pharmacokinetics of sustained-release tablets. It was concluded that the gastro-floating tablets had a sustained-release effect in vitro and in vivo, as well as desired pharmacokinetic properties in both fed and fasted conditions. PMID:23680730

Yin, Lifang; Qin, Chao; Chen, Kaisheng; Zhu, Chunli; Cao, Hui; Zhou, Jianping; He, Wei; Zhang, Qiang

2013-08-16

5

Formulation and evaluation of non-effervescent floating tablets of losartan potassium.  

PubMed

The aim of the work is to modify the solubility and bioavailability of Losartan potassium, by employing noneffervescent floating drug delivery (tablet dosage forms). Non-effervescent systems are a type of floating drug delivery systems, that have been used to boost the gastric residence and the floatation time in the gastro intestinal tract. The study included formulation of floating tablets using polymers like Chitosan and Karaya gum as matrix forming agents. Accurel(®) MP 1000 was used as floating agent. The tablets were prepared by direct compression technique. FTIR, DSC studies conformed that there was no incompatibility between the polymer and the drug. Tablet preformulation parameters were within the Pharmacopoeial limit. Tablet showed zero lag time, contisnuance of buoyancy for >12 h. The tablet showed good in vitro release. Drug release was through swelling and abided by the gellation mechanism. In vivo X-ray studies depicted that tablets continued to float in the GIT for 12 h. Accelerated stability showed that, tablets were stable for over 6 month. Thus the prepared non-effervescent floating tablet of Losartan potassium can be used for the treatment of hypertension for more than 12 h with single dose administration. PMID:23286884

Getyala, Anil; Gangadharappa, H V; Prasad, M Sarat Chandra; Reddy, M Praveen Kumar; Kumar, T M Pramod

2013-10-01

6

Effect of formulation parameters on the drug release and floating properties of gastric floating two-layer tablets with acetylsalicylic acid.  

PubMed

Floating dosage forms of acetylsalicylic acid, used for its antithrombotic effect, were developed to prolong gastric residence time and increase bioavailability. In the two-layer tablet formulation, hydroxypropyl methylcellulose (HPMC) of high viscosity and an effervescent mixture of citric acid and sodium bicarbonate formed the floating layer. The release layer contained the drug, direct tableting agent and different types of matrix-forming polymers such as HPMC of low viscosity, sodium carboxymethylcellulose and chitosan. Tablets were prepared using a direct compression technique. The effect of formulation variables on physicochemical and floating properties and the drug release from tablets were investigated. Floating ability was dependent on the amount of effervescent agent and gel-forming polymer of the floating layer. Drug release was prolonged to 8 hours by changing the type and viscosity of the matrix-forming polymer in the drug-loading layer and all formulations showed a diffusion release mechanisms. PMID:21945909

Hasçiçek, Canan; Yüksel-Tilkan, Günseli; Türkmen, Berna; Ozdemir, Nurten

2011-09-01

7

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

PubMed Central

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

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

2014-01-01

8

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

PubMed

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

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

2014-12-01

9

Formulation and evaluation of floating tablets of liquorice extract  

PubMed Central

Background: Floating tablets prolong the gastric residence time of drugs, improve bioavailability, and facilitate local drug delivery to the stomach. With this objective, floating tablets containing aqueous extract of liquorice as drug was prepared for the treatment of Helicobacter pylori and gastric ulcers. Methods: The aqueous extract of liquorice was standardized by HPTLC. Tablets containing HPMC K100M (hydrophilic polymer), liquorice extract, sodium bicarbonate (gas generating agent), talc, and magnesium stearate were prepared using direct compression method. The formulations were evaluated for physical parameters like diameter, thickness, hardness, friability, uniformity of weight, drug content, buoyancy time, dissolution, and drug release mechanism. The formulations were optimized on the basis of buoyancy time and in vitro drug release. Results: The diameter of all formulations was in the range 11.166–11.933 mm; thickness was in the range 4.02–4.086 mm. The hardness ranged from 3.1 to 3.5 kg/cm2. All formulations passed the USP requirements for friability and uniformity of weight. The buoyancy time of all tablet formulations was less than 5 min and tablet remained in floating condition throughout the study. All the tablet formulations followed zero-order kinetics and Korsemeyer-Peppas model in drug release. Conclusion: The optimized formulation was found to be F6 which released 98.3% of drug in 8 h in vitro, while the buoyancy time was 3.5 min. Formulations containing psyllium husk, sodium bicarbonate and HPMC K100M in combination can be a promising for gastroretentive drug delivery systems. PMID:21589757

Ram, H. N. Aswatha; Lachake, Prachiti; Kaushik, Ujjwal; Shreedhara, C. S.

2010-01-01

10

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

PubMed

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

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

2015-01-01

11

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

PubMed Central

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.

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

2015-01-01

12

Preparation and evaluation of dual-mode floating gastroretentive tablets containing itraconazole.  

PubMed

The aims of the present study were to prepare new dual-mode floating gastroretentive tablets (DF-GRT) containing itraconazole (ITR) and to evaluate influence of the dosage forms on pharmacokinetic parameters of ITR. The solubility of ITR was enhanced around 200 times (from 1.54 to 248.38?µg/mL) by preparing solid dispersion (SD) with hydroxypropylmethyl cellulose. Buoyancy of DF-GRT containing ITR-SD was established by both camphor sublimation and gas generation. Camphor sublimation decreased density of DF-GRT by making pores in tablet matrix, which led to elimination of lag time for floating. Carbon dioxide generated by sodium bicarbonate and citric acid helped to maintain buoyancy of DF-GRT. Therefore DF-GRT floated on the medium without lag time until disintegrated entirely during in vitro release study. They released 89.11% of the drug at 2?h. Residual camphor was <0.5?wt% after sublimation. The pharmacokinetics of DF-GRT was evaluated in six miniature pigs and compared to immediate release tablets (IRT). Mean AUC ratio of GRT/IRT was 1.36 but there was no statistical difference between AUC values. However delayed tmax, increased MRT and equivalent Cmax of DF-GRT supposed it could be a promising tool for gastroretentive drug delivery system containing ITR. PMID:24245857

Kim, Ju-Young; Rhee, Yun-Seok; Park, Chun-Woong; Ha, Jung-Myung; Park, Eun-Seok

2014-11-01

13

[Modern polymers in matrix tablets technology].  

PubMed

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

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

2014-01-01

14

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

PubMed

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

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

2014-09-22

15

Release Mechanisms Behind Polysaccharides-Based Famotidine Controlled Release Matrix Tablets  

Microsoft Academic Search

Polysaccharides, which have been explored to possess gelling properties and a wide margin of safety, were used to formulate\\u000a single-unit floating matrix tablets by a direct compression technique. This work has the aim to allow continuous slow release\\u000a of famotidine above its site of absorption. The floating approach was achieved by the use of the low density polypropylene\\u000a foam powder.

Enas M. Elmowafy; Gehanne A. S. Awad; Samar Mansour; Abd El-Hamid A. El-Shamy

2008-01-01

16

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

PubMed

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

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

2012-12-01

17

Development and evaluation of gastroretentive floating tablets of an antihypertensive drug using hydrogenated cottonseed oil.  

PubMed

The aim of the present work was to develop a gastroretentive floating tablet of Atenolol and investigate the effects of both hydrophilic and hydrophobic retardant on in vitro release. Atenolol is an antihypertensive drug with an oral bioavailability of only 50% because of its poor absorption from lower gastrointestinal tract. The floating tablets of Atenolol were prepared to increase the gastric retention, to extend the drug release, and to improve the bioavailability of the drug. The floating tablets were formulated using hydrophilic polymers as Hydroxy propyl methyl cellulose (HPMC K4M and HPMC K15M), hydrophobic retardant as a hydrogenated cottonseed oil (HCSO), and sodium bicarbonate as a gas generating agent to reduce floating lag time. The formulated tablets were evaluated for the quality control tests such as weight variation, hardness, friability, swelling index, floating lag time, and total floating time. The in vitro release study of the tablets was performed in 0.1?N HCl as a dissolution media. The results of the present study clearly indicates the promising potential of Atenolol floating system as an alternative to the conventional dosage and other sustained release formulations. The study also revealed the effectiveness of HCSO as retardant in combination with HPMC. PMID:24455312

Pawar, Harshal Ashok; Gharat, Pooja Ramchandra; Dhavale, Rachana Vivek; Joshi, Pooja Rasiklal; Rakshit, Pushpita Pankajkumar

2013-12-18

18

Floating-Point Matrix Multiplication in a Polymorphic Processor  

E-print Network

Floating-Point Matrix Multiplication in a Polymorphic Processor Georgi Kuzmanov, Member, IEEE and Wouter M. van Oijen Abstract--We consider 64-bit floating-point matrix multi- plication in the context for large problem sizes. Index Terms--Floating-point arithmetic, Matrix multipli- cation, Polymorphic

Kuzmanov, Georgi

19

Formulation development, optimization, and evaluation of sustained release tablet of valacyclovir hydrochloride by combined approach of floating and swelling for better gastric retention.  

PubMed

The present study is intended to enhance gastric retention of sustained release tablet of valacyclovir hydrochloride by combined approach of floating and swelling. The tablets are prepared by direct compression method. Polyethylene oxide (Polyox WSR 303) is selected as the swelling matrix agent. Sodium starch glycolate (SSG) is used as swelling enhancer, and sodium bicarbonate is used as an effervescent agent for floating. A 3(2) full factorial design is applied to systematically optimize the formulation. The concentration of Polyox WSR 303 (X 1) and concentration of SSG (X 2) are selected as independent variables. The percentage drug release at 12 h, floating lag time, and maximum percentage swelling are selected as dependent variables. Formulations are evaluated for hardness, friability, floating lag time, total floating time, percentage swelling, in vitro drug release, and in vivo floating study. The results indicated that X 1 and X 2 significantly affected the drug release properties, floating lag times, and maximum percentage swelling. Release rate decreases as the concentration of Polyox increased. Regression analysis and numerical optimization are performed to identify the best formulation. Formulation F5 prepared with Polyox WSR 303 (15 %) and SSG (10 %) is found to be the best formulation. F5 followed zero-order release mechanism. Swelling and floating gastroretentive tablets of valacyclovir HCl are successfully formulated with controlled delivery to stomach with an aim of increasing the mean residence time in the upper part of GIT where the drug has its absorption window. PMID:25787207

Upadhyay, Pratik; Nayak, Kunal; Patel, Kaushika; Patel, Jaymin; Shah, Shreeraj; Deshpande, Jayant

2014-12-01

20

Physiological relevant in vitro evaluation of polymer coats for gastroretentive floating tablets.  

PubMed

Gastroretentive drug delivery systems are retained in the stomach for a sufficient time interval, releasing the drug in a controlled manner. According to literature, the floating principle is the most frequently used formulation approach for gastric retention. However, many publications lack information of the floating forces, the impact of different pH-values and almost no information exist concerning the resistance of the floating performance against physiological relevant stress. Therefore, we evaluated the performance of CO2-generating floating bilayer (drug and floating layer) tablets with respect to robustness, drug release profile, pH dependence and floating behaviour. Bilayer tablets were coated with a flexible and water permeable, but CO2-retaining polymer film of either polyvinyl acetate or ammonio-methacrylate copolymer type A. Metformin-HCl was used as a relevant model drug due to its dose-dependent and saturable absorption from the proximal part of the small intestine. To mimic physiological relevant mechanical stress conditions, recently developed dissolution stress tests with pulsed pressures were applied in addition to release studies according to the pharmacopeia. Bilayer tablets coated with polyvinyl acetate showed short floating lag times, reasonable floating strength values, floating durations of more than 24h in simulated gastric fluid and a robust and pH independent release of Metformin-HCl. Tablets coated with ammonio-methacrylate copolymer type A showed a higher permeability for the active ingredient combined with a decreased robustness of the inflated tablets. Both polymers can be used for balloon-like floating devices. The appropriate polymer has to be chosen dependent from the properties of the active ingredient and requested application of the delivery device. Furthermore, the dissolution stress test analysis is able to indicate possible safety issues of gastroretentive formulations as well as to characterise the robustness of formulation principles towards mechanical stresses of bio-relevant intensity. PMID:25086221

Eisenächer, Friederike; Garbacz, Grzegorz; Mäder, Karsten

2014-11-01

21

Floating Point Architecture Extensions for Optimized Matrix Factorization  

E-print Network

Floating Point Architecture Extensions for Optimized Matrix Factorization Ardavan Pedram, Andreas of redesigning floating point units and their surrounding data- paths to support these complicated operations. We even in the complex inner kernels of these operations. I. INTRODUCTION Modern computers use floating

Gerstlauer, Andreas

22

Impact of anti-tacking agents on properties of gas-entrapped membrane and effervescent floating tablets.  

PubMed

Tackiness caused by the gas-entrapped membrane (Eudragit(®)RL 30D) was usually observed during storage of the effervescent floating tablets, leading to failure in floatation and sustained release. In this work, common anti-tacking agents (glyceryl monostearate (GMS) and talc) were used to solve this tackiness problem. The impact of anti-tacking agent on the properties of free films and corresponding floating tablets was investigated. GMS was more effective than talc in reducing tackiness of the film. Addition and increasing amount of anti-tacking agents lowered the film mechanical strength, but the coating films were still strong and flexible enough to resist the generated gas pressure inside the floating tablet. Wettability and water vapor permeability of the film decreased with increasing level of anti-tacking agents as a result of their hydrophobicity. No interaction between anti-tacking agents and polymer was observed as confirmed by Fourier transform infrared spectroscopy, powder X-ray diffractometry, and differential scanning calorimetry studies. Increasing amount of anti-tacking agents decreased time to float and tended to retard drug release of the floating tablets. Floating properties and drug release were also influenced by type of anti-tacking agents. The obtained floating tablets still possessed good floating properties and controlled drug release even though anti-tacking agent had some effects. The results demonstrated that the tackiness problem of the floating tablets could be solved by incorporating anti-tacking agent into the gas-entrapped membrane. PMID:24927669

Kriangkrai, Worawut; Puttipipatkhachorn, Satit; Sriamornsak, Pornsak; Pongjanyakul, Thaned; Sungthongjeen, Srisagul

2014-12-01

23

Evaluating Energy Efficiency of Floating Point Matrix Multiplication on FPGAs  

E-print Network

Evaluating Energy Efficiency of Floating Point Matrix Multiplication on FPGAs Kiran Kumar Matam, prasanna}@usc.edu Abstract--Energy efficiency has emerged as one of the key performance metrics in scientific computing. In this work, we evaluate the energy efficiency of floating point matrix multipli

Prasanna, Viktor K.

24

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

E-print Network

containing Eudragit® RS PO and/or Eudragit® E PO. Acetohydroxamic acid and chlorpheniramine maleate were used. The HME tablets prepared from the powder blend containing both Eudragit® RS PO and sodium bicarbonate was controlled by both the incorporation of Eudragit® E PO into the matrix tablet and the diameter of the die

Peppas, Nicholas A.

25

Floating-point sparse matrix-vector multiply for FPGAs  

Microsoft Academic Search

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

Michael deLorimier; André DeHon

2005-01-01

26

Gastro-floating bilayer tablets for the sustained release of metformin and immediate release of pioglitazone: Preparation and in vitro/in vivo evaluation.  

PubMed

Owing to the complementary mechanisms of action of metformin hydrochloride (MH) and pioglitazone hydrochloride (PG), combination therapy for type 2 diabetes mellitus using the two drugs is highly desired; on the other hand, MH is not well absorbed in lower gastrointestinal tract and has a short half-life, therefore compromising the therapeutic effects. Herein, the present study was to develop gastro-floating bilayer matrix tablets in which the two drugs were incorporated into two separate layers, aiming at sustaining MH release with enhanced absorption and achieving immediate release of PG. The tablets of the optimized formulation floated on the test medium for more than 24h with 5min of floating lag time, and sustained MH release for 12h via a diffusion-dependent manner; and complete release of PG within 5min were achieved. Moreover, a steady plasma concentration of MH with a 1.5-fold increase in bioavailability, decreased Cmax and reduced Tmax was obtained, and the in vivo behavior of PG was similar to the marked product. Summarily, sustained MH release with improved absorption and immediate release of PG were obtained simultaneously using the gastro-floating bilayer tablet, allowing strengthened combination therapy for diabetes mellitus. PMID:25283698

He, Wei; Li, Yongji; Zhang, Rao; Wu, Zhannan; Yin, Lifang

2014-12-10

27

Liquid boundary movements in cylindrical and convex hydrophobic matrix tablets: Effects on tablet cracking and drug release.  

PubMed

The aim of this study was to investigate liquid penetration into both cylindrical and convex hydrophobic matrix tablets and to relate the changes in tablet structure to drug release. Starch acetate with degree of substitution of 2.7 was used as a hydrophobic matrix former and anhydrous caffeine as a freely soluble model drug. Phenolred was used as a colouring agent to enhance the visual detection of the liquid boundary movements, which were examined in axial and radial directions for both types of tablets. The tablets started to expand during the dissolution, resulting in cracking as the liquid boundary penetrated into tablet. The cracking influences drug release by shortening the diffusion path and decreasing the tortuosity. The liquid boundaries proceed differently in cylindrical and convex tablets, this being attributable to differences in pore structure and density distribution. Cylindrical tablets are quite homogeneous in terms of density, but convex tablets have more porous areas at the domes of the tablet. PMID:16846722

Pajander, Jari; van Veen, Bert; Korhonen, Ossi; Lappalainen, Reijo; Ketolainen, Jarkko

2006-10-01

28

Formulation and Evaluation of Swellable and Floating Gastroretentive Ciprofloxacin Hydrochloride Tablets  

Microsoft Academic Search

Drugs that have narrow absorption window in the gastrointestinal tract (GIT) will have poor absorption. For these drugs, gastroretentive\\u000a drug delivery systems offer the advantage in prolonging the gastric emptying time. Swellable, floating, and sustained release\\u000a tablets are developed by using a combination of hydrophilic polymer (hydroxypropyl methylcellulose), swelling agents (crospovidone,\\u000a sodium starch glycolate, and croscarmelose sodium) and effervescent substance

Ramji Anil Kumar Arza; Chandra Sekhara Rao Gonugunta; Prabhakar Reddy Veerareddy

2009-01-01

29

Optimization and evaluation of clarithromycin floating tablets using experimental mixture design.  

PubMed

The purpose of the study was to prepare and evaluate clarithromycin (CLA) floating tablets using experimental mixture design for treatment of Helicobacter pylori provided by prolonged gastric residence time and controlled plasma level. Ten different formulations were generated based on different molecular weight of hypromellose (HPMC K100, K4M, K15M) by using simplex lattice design (a sub-class of mixture design) with Minitab 16 software. Sodium bicarbonate and anhydrous citric acid were used as gas generating agents. Tablets were prepared by wet granulation technique. All of the process variables were fixed. Results of cumulative drug release at 8th h (CDR 8th) were statistically analyzed to get optimized formulation (OF). Optimized formulation, which gave floating lag time lower than 15 s and total floating time more than 10 h, was analyzed and compared with target for CDR 8th (80%). A good agreement was shown between predicted and actual values of CDR 8th with a variation lower than 1%. The activity of clarithromycin contained optimizedformula against H. pylori were quantified using well diffusion agar assay. Diameters of inhibition zones vs. log10 clarithromycin concentrations were plotted in order to obtain a standard curve and clarithromycin activity. PMID:25272652

U?urlu, Timucin; Karaçiçek, U?ur; Rayaman, Erkan

2014-01-01

30

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

E-print Network

Research paper Pore shape in the sodium chloride matrix of tablets after the addition of starch xxxx Keywords: Pore shape Porosity Tablet strength Pore structure Binary mixture a b s t r a c in pore shape in the matrix of the primary component, causing a decrease in mechanical strength. Tablets

van Vliet, Lucas J.

31

Optimization of HPMC and carbopol concentrations in non-effervescent floating tablet through factorial design.  

PubMed

This study was to optimize HPMC K4M and carbopol 934 concentration in the development of non-effervescent floating tablets (NEFTs) of glipizide as model drug using 3(2) factorial design. The time required for releasing drug of 50% and 80% and similarity factor were the target responses. HPMC K4M and carbopol 934 concentrations were the variables. The response surface methodology and optimized polynomial equations were used to select the optimal formulation with desired responses. The excipients used in tablets were compatible with glipizide as per the results of isothermal stress testing and DSC study. The drug release of entire NEFTs followed zero order kinetics and non-Fickian diffusion mechanism. Validation of the optimization technique demonstrated the reliability of the model. The optimized formulation containing 124.33 mg HPMC K4M and 25.76 mg carbopol 934 was prepared according to the software determined levels. The stability study of the optimized formulation proved the integrity of the developed formulation. PMID:24507292

Acharya, Sujata; Patra, Sradhanjali; Pani, Nihar Ranjan

2014-02-15

32

Matrix tablets are drug delivery devices that release a water-soluble drug over an extended period of time. Such matrix tablets are formulated from mixtures of drug, polymer, and excipient  

E-print Network

Summary Matrix tablets are drug delivery devices that release a water-soluble drug over an extended period of time. Such matrix tablets are formulated from mixtures of drug, polymer, and excipient powders variation in the drug release profile of the tablet. While fabrication of experimental tablets

Hinow, Peter

33

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

E-print Network

Scalable and Modular Algorithms for Floating-Point Matrix Multiplication on FPGAs Ling Zhuo computations. In this paper, we propose two FPGA-based algorithms for floating-point matrix multiplication. The processing elements(PEs) used in our algorithms are modular so that floating-point units can be easily

Prasanna, Viktor K.

34

Accurate Matrix Multiplication with Multiple Floating-point Numbers Katsuhisa Ozaki  

E-print Network

Accurate Matrix Multiplication with Multiple Floating-point Numbers Katsuhisa Ozaki , Takeshi Ogita computation of matrix multiplication, where components of matrices are represented by summation of floating that the computed result is one of the floating-point neigh- bors of a true result. Moreover, ROO algorithm has

Rump, Siegfried M.

35

New insights on poly(vinyl acetate)-based coated floating tablets: Characterisation of hydration and CO 2 generation by benchtop MRI and its relation to drug release and floating strength  

Microsoft Academic Search

The purpose of this study was to investigate the mechanism of floating and drug release behaviour of poly(vinyl acetate)-based floating tablets with membrane controlled drug delivery. Propranolol HCl containing tablets with Kollidon® SR as an excipient for direct compression and different Kollicoat® SR 30 D\\/Kollicoat® IR coats varying from 10 to 20mg polymer\\/cm2 were investigated regarding drug release in 0.1N

Sandra Strübing; Tâmara Abboud; Renata Vidor Contri; Hendrik Metz; Karsten Mäder

2008-01-01

36

Dissolution parameters for sodium diclofenac-containing hypromellose matrix tablet.  

PubMed

Sodium diclofenac (SD) release from dosage forms has been studied under different conditions. However, no dissolution method that is discriminatory enough to reflect slight changes in formulation or manufacturing process, and which could be effectively correlated with the biological properties of the dosage form, has been reported. This study sought to develop three different formulae of SD-containing matrix tablets and to determine the effect of agitation speed in its dissolution profiles. F1, F2 and F3 formulations were developed using hypromellose (10, 20 and 30%, respectively for F1, F2 and F3) and other conventional excipients. Dissolution tests were carried out in phosphate buffer pH 6.8 at 37 degrees C using apparatus II at 50, 75 or 100 rpm. Dissolution efficiency (DE), T(50) and T(90) were determined and plotted as functions of the variables agitation speed and hypromellose concentration. Regarding DE, F2 showed more sensitivity to variations in agitation speed than F1 and F3. Increasing hypromellose concentration reduced DE values, independent of agitation speed. Analysis of T(50) and T(90) suggests that F1 is less sensitive to variations in agitation speed than F2 and F3. Most discriminatory dissolution conditions were observed at 50 rpm. Results suggest that the comparison of dissolution performance of SD matrix tablets should take into account polymer concentration and agitation conditions. PMID:19941944

Mourão, Samanta C; da Silva, Cristiane; Bresolin, Tania M B; Serra, Cristina H R; Porta, Valentina

2010-02-15

37

Predicting the Drug Release Kinetics of Matrix Tablets  

E-print Network

In this paper we develop two mathematical models to predict the release kinetics of a water soluble drug from a polymer/excipient matrix tablet. The first of our models consists of a random walk on a weighted graph, where the vertices of the graph represent particles of drug, excipient and polymer, respectively. The graph itself is the contact graph of a multidisperse random sphere packing. The second model describes the dissolution and the subsequent diffusion of the active drug out of a porous matrix using a system of partial differential equations. The predictions of both models show good qualitative agreement with experimental release curves. The models will provide tools for designing better controlled release devices.

Baeumer, Boris; Hinow, Peter; Rades, Thomas; Radunskaya, Ami; Tucker, Ian

2008-01-01

38

Floating matrix dosage form for dextromethorphan hydrobromide based on gas forming technique: in vitro and in vivo evaluation in healthy volunteers.  

PubMed

The objective of this study was to develop the dextromethorphan hydrobromide sustained-release (DMB-SR) tablets using floating technique to prolong the gastric residence time and compared their pharmacokinetic behavior with conventional sustained release tablets. DMB-SR floating tablets were prepared employing hydroxypropyl methylcellulose (HPMC) as hydrophilic gel material, sodium bicarbonate as gas-generating agent and hexadecanol as floating assistant agent. An orthogonal experiment design method was used to select the optimized formulation. The floating tablets were evaluated for uniformity of weight, hardness, friability, drug content, floating characteristics, in vitro release and in vivo bioavailability. The optimized tablets were prepared with HPMC K4M 25 mg, sodium bicarbonate 20 mg and hexadecanol 18 mg. The prepared tablets could float within 3 min and maintain for more than 24 h. The data of physical parameters were all lie within the limits. Drug release at 12 h was more than 85%. The comparative pharmacokinetic study was performed by administration of the DMB-SR floating tablets and conventional DMB-SR tablets. The area under curve of plasma concentration-time (AUC) of floating tablets was slightly higher than that of reference tablets, T(max) was prolonged apparently. The results showed the floating tablets are a feasible approach for the sustained-release preparation of drugs, which have limited absorption sites in the stomach. PMID:21050887

Hu, Liandong; Li, Li; Yang, Xun; Liu, Wei; Yang, Jianxue; Jia, Yanhong; Shang, Chuang; Xu, Hongxin

2011-01-18

39

Development and evaluation of hydrophilic colloid matrix of famotidine tablets.  

PubMed

The objective of the present study was to develop a once-daily sustained-release (SR) matrix tablet of famotidine. Nine different formulations (F1-F9) were prepared by direct compression method using Avicel PH101 as filler/binder in the range of 41-27% in F1-F3, 18-22% in F4-F7, and 16-18% in F8-F9 and hydroxypropyl methylcellulose (4,000 cps) as hydrophilic matrix was used in F1-F3 from 19% to 30%, around 40% in F4-F7, and 42-45% in F8-F9. Talc and Aerosil were added in the ratio of 0.7-1.2%. The tablets were subjected to various physical parameters including weight variation test, hardness, thickness, diameter, friability, and in vitro release studies. Assay was also performed according to the USP 30 NF 25 procedure. The results of the physical parameters and assay were found to be within the acceptable range. In vitro dissolution results indicated that formulation F4-F7, having around 40% of rate control polymer, produced a SR pattern throughout 24 h. F1-F3 showed drug release at a faster rate, while F8-F9 released much slower, i.e., <80% in 24 h. Model-dependent and model-independent methods were used for data analysis and the best results were observed for F4 in zero order (r(2) = 0.984) and F6 in Korsmeyer and Higuchi (r(2) = 0.992 and 0.988). The parameter n indicated anomalous diffusion, while beta in Weibull showed a parabolic curve with higher initial slope. The f(2) similarity test was performed taking F4 as a reference formulation. Only the F5-F7 formulations were similar to the reference formulation F4. The mean dissolution time was around 10 h for the successful formulation. PMID:20422332

Shoaib, Muhammad Harris; Al Sabah Siddiqi, Saniah; Yousuf, Rabia Ismail; Zaheer, Kamran; Hanif, Muhammad; Rehana, Saeed; Jabeen, Sabahat

2010-06-01

40

Preparation of Coated Valproic Acid and Sodium Valproate Sustained-release Matrix Tablets  

PubMed Central

The aim of this research was to investigate the technique for preparation of coated valproic acid and sodium valproate sustained-release matrix tablets. Different diluents were tested and selected as the effective absorbent for oily valproic acid. Effect of the amount of absorbent and hydroxypropylmethylcellulose on drug release from valproic acid-sodium valproate matrix tablets prepared with wet granulation technique was evaluated in pH change system. Colloidal silicon dioxide effectively adsorbed liquid valproic acid during wet granulation and granule preparation. The amounts of colloidal silicon dioxide and hydroxypropylmethylcellulose employed in tablet formulations affected drug release from the tablets. The drug release was prominently sustained for over 12 h using hydroxypropylmethylcellulose-based hydrophilic matrix system. The mechanism of drug release through the matrix polymer was a diffusion control. The drug release profile of the developed matrix tablet was similar to Depakine Chrono®, providing the values of similarity factor (f2) and difference factor (f1) of 85.56 and 2.37, respectively. Eudragit® L 30 D-55 was used as effective subcoating material for core matrix tablets before over coating with hydroxypropylmethylcellulose film with organic base solvent. Drug release profile of coated matrix tablet was almost similar to that of Depakine Chrono®. PMID:20838520

Phaechamud, T.; Mueannoom, W.; Tuntarawongsa, S.; Chitrattha, S.

2010-01-01

41

Formulation and in vivo evaluation of diclofenac sodium sustained release matrix tablet: Effect of compression force.  

PubMed

In the present study, Diclofenac Sodium (DS) matrix tablets were prepared by direct compression method under different compression forces (5, 10, 15 and 20 KN), using ethylcellulose as matrix forming material. The produced tablets were characterized on the foundation of satisfactory tablet properties such as hardness, friability, drug content, weight variations and in vitro drug release rate. Differential scanning calorimetry (DSC), Fourier Transform Infrared (FT-IR) spectroscopy and X-ray diffraction have been used to investigate any incompatibilities of the tablet's ingredients. Additionally, in vivo bioavailability has been investigated on beagle dogs. Data obtained revealed that, upon increasing compression force the in vitro drug release was sustained and the Tmax value was four hours (for formulations compressed at 15 and 20 kN) compared to the conventional voltarine® 50 tablets (Tmax value of 2 hours). PMID:25730790

Taha, Ehab Ibrahim; Shazly, Gamal Abdel-Ghany; Harisa, Gamaleldin Ibrahim; Barakat, Nahla Sedik; Al-Enazi, Fouza Kayem; Elbagory, Ibrahim Mostafa

2015-03-01

42

Floating elementary osmotic pump tablet (FEOPT) for controlled delivery of diethylcarbamazine citrate: a water-soluble drug.  

PubMed

The present work investigates the feasibility of the design of a novel floating elementary osmotic pump tablet (FEOPT) to prolong the gastric residence of a highly water-soluble drug. Diethylcarbamazine citrate (DEC) was chosen as a model drug. The FEOPT consisted of an osmotic core (DEC, mannitol, and hydrophilic polymers) coated with a semipermeable layer (cellulose acetate) and a gas-generating gelling layer (sodium bicarbonate, hydrophilic polymers) followed by a polymeric film (Eudragit RL 30D). The effect of formulation variables such as concentration of polymers, types of diluent, and coat thickness of semipermeable membrane was evaluated in terms of physical parameters, floating lag time, duration of floatation, and in vitro drug release. The Fourier transform infrared and X-ray diffraction analysis were carried out to study the physicochemical changes in the drug excipients powder blend. The integrity of the orifice and polymeric film layer was confirmed from scanning electron microscopy image. All the developed FEOPT showed floating lag time of less than 8 min and floating duration of 24 h. A zero-order drug release could be attained for DEC. The formulations were found to be stable up to 3 months of stability testing at 40°C/75% relative humidity. PMID:21969244

Khan, Zulfequar Ahamad; Tripathi, Rahul; Mishra, Brahmeshwar

2011-12-01

43

In vitro aceclofenac release from IPN matrix tablets composed of chitosan-tamarind seed polysaccharide.  

PubMed

This communication describes the formulation and in vitro evaluation of IPN matrix tablets of aceclofenac. IPN microparticles using chitosan and tamarind seed polysaccharide blend was prepared using glutaraldehyde as cross-linker. The drug entrapment efficiency and average particle size of these microparticles was found to be 91.97±1.30% and 498.12±38.67 ?m, respectively. These IPN microparticles were characterized by scanning electron microscopy (SEM) and powder X-ray diffraction (P-XRD) study. These microparticles were compressed with tablet excipients through direct compression technique. These matrix tablets showed sustained aceclofenac release over 8 h. These matrix tablets might be helpful to minimize dosing frequency and reduction of various side effects during prolong period of treatment. PMID:24463265

Jana, Sougata; Sen, Kalyan Kumar; Basu, Sanat Kumar

2014-04-01

44

Albizia procera gum as an excipient for oral controlled release matrix tablet.  

PubMed

The purpose of this research was to develop and evaluate controlled release matrix tablets of paracetamol based on natural gum exudates of Albizia procera. Procera gum was characterized of its properties like compressibility index, angle of repose, viscosity and moisture content. The interaction between the gum and paracetamol was also studied through differential scanning calorimetry (DSC) and FTIR spectroscopy. Matrix tablets were then prepared by wet granulation method with different concentrations of procera gum and hydroxypropyl methylcellulose (HPMC) and evaluated for their physical properties like weight variation, hardness, friability and content uniformity. Dissolution study was conducted to characterize release mechanism from the matrix system and data were fitted to various kinetic models. The mechanism of drug release from both types of matrix tablets was found to be anomalous type. Results from various evaluations suggested that A. procera gum could be used as drug release retardant in controlled release matrix systems. PMID:24751043

Pachuau, Lalduhsanga; Mazumder, Bhaskar

2012-09-01

45

Bilayer matrix tablets for prolonged actions of metformin hydrochloride and repaglinide.  

PubMed

A combination therapy of metformin hydrochloride (MH) and repaglinide (RG) achieves a perfect glycemic control; however, the combination formulation of immediate release must be taken several times a day, compromising the therapeutic benefits and causing inconveniences to the patients. Herein, a bilayer matrix tablet that aimed at continuously releasing both MH and RG over time was developed, in which the two drugs were formulated into two separated layers. The tablets were prepared by wet granulation method, and the optimized formulation was obtained by evaluating the factors that affected the drug release. The bilayer tablets simultaneously released the two drugs over 12 h; and a better in vivo performance with a steady plasma concentration, markedly lower C max, prolonged T max, and perfect absorption was obtained. Summarily, the bilayer matrix tablets sustained both MH and RG release over time, thereby prolonging the actions for diabetic therapy and producing better health outcomes. PMID:25319054

He, Wei; Huang, Shijing; Zhou, Chunyan; Cao, Lin; Yao, Jing; Zhou, Jianping; Wang, Guangji; Yin, Lifang

2015-04-01

46

Effect of processing and sintering on controlled release wax matrix tablets of ketorolac tromethamine.  

PubMed

The objective of present study was to evaluate the effect of processing methods and sintering condition on matrix formation and subsequent drug release from wax matrix tablets for controlled release. Ketorolac tromethamine and compritol were processed with appropriate diluent using either dry blending, spray drying, partial melt granulation or melt granulation.The tablets were then sintered at 80 degrees . The sintered tablets were characterized by their physical parameters and in vitro dissolution tests. The micro-morphology and wettability of the tablets was also investigated. It was evident that different processing methods for identical formulation significant impact the release profile of drug. Sintering further retarded drug release and its effect was related to the manufacturing processes. Scanning electron microscopy showed that heat treatment redistributed the wax and formed a film-like structure covering drug and excipient particle. The contact angle of tablets made by dry blending, spray drying and partial melt granulation methods increased after sintering, while that of tablets made by melt granulation remained constant. Drug release from the wax tablets with or without heat treatment was best described by the Higuchi equation. Different processing methods produced different matrix structures that resulted in different drug release rates. Sintering retarded drug release mainly by decreasing the porosity of the matrix. Contact angle measurement and SEM analysis indicated that heat treatment caused the wax to melt, redistribute, coat the drug and diluents and form a network structure. Differential scanning calorimetry studies ruled out the occurrence of solid solution of the drug during sintering condition. PMID:20502573

Rao, Monica R P; Ranpise, Anuradha A; Thanki, K C; Borate, S G; Parikh, G N

2009-09-01

47

FORMULATION AND IN-VITRO EVALUATION OF DEXTRIN MATRIX TABLET OF IBUPROFEN FOR COLON SPECIFIC DRUG DELIVERY  

Microsoft Academic Search

The objective of the present study is to develop colon targeted drug delivery system by using dextrin (polysaccharide) as a carrier for ibuprofen. Matrix tablets containing various excipients and dextrin were prepared by wet granulation technique using different binder systems. The matrix tablets were evaluated by different IPQC tests, content uniformity and in vitro drug release study. Drug release profile

KISHOR SAHEBRAO SALUNKHE; MOHAN VINAYAK KULKARNI

48

Effect of Kollidon® SR on the release of Albuterol Sulphate from matrix tablets  

PubMed Central

The objective of this study was to evaluate Kollidon SR for the development of extended release Albuterol Sulphate matrix tablets in comparison with other polymers as Hydroxypropylmethylcellulose K15M, Carbopol 71G NF, and Eudragit L100-55. The mechanical properties of the tablets were improved as concentration of Kollidon SR or other polymers increased. It was found that Kollidon SR 30% (w/w) and HPMC 30% (w/w) tablets have f2 similarity factor of 83.5 in their Albuterol Sulphate dissolution profile. The marketed product was found to release 99.7% of drug content within 8 h, while Kollidon SR and HPMC tablets with 30% (w/w) polymer concentration level released 92.7% and 92.9% respectively of drug content within 8 h. Kollidon SR has a unique character of maintaining tablets geometric shape until the end of dissolution test, this is mainly due to the water insoluble content, polyvinyl acetate, forming 80% (w/w) of Kollidon SR, while the remaining content 20% (w/w) is the water soluble, polyvinylpyrrolidone, responsible for pore formation causing a diffusion controlled release. Drug release from all previous formulations is best described to be controlled by more than one kinetic mechanism of release. In conclusion, Kollidon SR and HPMC and Carbopol were found to be potential candidates for the development of extended release of Albuterol Sulphate tablets. PMID:24115901

Sakr, Walid; Alanazi, Fars; Sakr, Adel

2010-01-01

49

Colonic luminal surface retention of meloxicam microsponges delivered by erosion based colon-targeted matrix tablet.  

PubMed

The work was aimed at developing calcium-pectinate matrix tablet for colon-targeted delivery of meloxicam (MLX) microsponges. Modified quassi-emulsion solvent diffusion method was used to formulate microsponges (MS), based on 3(2) full factorial design. The effects of volume of dichloromethane and EudragitRS100 content (independent variables) were determined on the particle size, entrapment efficiency and %cumulative drug release of MS1-MS9. The optimized formulation, MS5 (d(mean)=44.47 ?m, %EE=98.73, %CDR=97.32 and followed zero order release) was developed into colon-targeted matrix tablet using calcium pectinate as the matrix. The optimized colon-targeted tablet (MS5T2) shielded MLX loaded microsponges in gastrointestinal region and selectively delivered them to colon, as vizualized by vivo fluoroscopy in rabbits. The pharmacokinetic evaluation of MS5T2 in rabbits, revealed appearance of drug appeared in plasma after a lag time of 7h; a t(max) of 30 h with Fr=61.047%, thus presenting a formulation suitable for targeted colonic delivery. CLSM studies provided an evidence for colonic luminal retentive ability of microsponges at the end of 8h upon oral administration of MS5T2. Thus calcium pectinate matrix tablet loaded with MLX microsponges was developed as a promising system for the colon-specific delivery that has potential for use as an adjuvant therapy for colorectal cancer. PMID:22306039

Srivastava, Rishabh; Kumar, Deepesh; Pathak, Kamla

2012-05-10

50

Swallowing a cellular automaton pill: predicting drug release from a matrix tablet  

E-print Network

Matrix tablets are drug delivery devices designed to release a drug in a controlled manner over an extended period of time. We develop a cellular automaton (CA) model for the dissolution and release of a water-soluble drug and excipient from a matrix tablet of water-insoluble polymer. Cells of the CA are occupied by drug, excipient, water or polymer and the CA updating rules simulate the dissolution of drug and excipient and the subsequent diffusion of the dissolved substances. In addition we simulate the possible fracture of brittle drug and excipient powders during the tablet compression and the melting of the polymer during a possible thermal curing process. Different stirring mechanisms that facilitate the transport of dissolved drug in the fluid in which the tablet is immersed are modeled in the water cells adjacent to the boundary of the tablet. We find that our simulations can reproduce experimental drug release profiles. Our simulation tool can be used to streamline the formulation and production of s...

Buchla, Ezra; Najera, Aisha; Radunskaya, Ami

2012-01-01

51

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

PubMed Central

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

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

2014-01-01

52

Design of Controlled Release Non-erodible Polymeric Matrix Tablet Using Microwave Oven-assisted Sintering Technique  

PubMed Central

The objective of the present study was to evaluate the effect of sintering condition on matrix formation and subsequent drug release from polymer matrix tablet for controlled release. The present study highlights the use of a microwave oven for the sintering process in order to achieve more uniform heat distribution with reduction in time required for sintering. We could achieve effective sintering within 8 min which is very less compared to conventional hot air oven sintering. The tablets containing the drug (propranolol hydrochloride) and sintering polymer (eudragit S-100) were prepared and kept in a microwave oven at 540 watt, 720 watt and 900 watt power for different time periods for sintering. The sintered tablets were evaluated for various tablet characteristics including dissolution study. Tablets sintered at 900 watt power for 8 min gave better dissolution profile compared to others. We conclude that microwave oven sintering is better than conventional hot air oven sintering process in preparation of controlled release tablets. PMID:21897655

Patel, DM; Patel, BK; Patel, HA; Patel, CN

2011-01-01

53

Matrix-mini-tablets of lornoxicam for targeting early morning peak symptoms of rheumatoid arthritis  

PubMed Central

Objective(s): The aim of present research was to develop matrix-mini-tablets of lornoxicam filled in capsule for targeting early morning peak symptoms of rheumatoid arthritis. Materials and Methods: Matrix-mini-tablets of lornoxicam were prepared by direct compression method using microsomal enzyme dependent and pH-sensitive polymers which were further filled into an empty HPMC capsule. To assess the compatibility, FT-IR and DSC studies for pure drug, polymers and their physical mixture were performed. The formulated batches were subjected to physicochemical studies, estimation of drug content, in vitro drug release, drug release kinetics, and stability studies. Results: When FTIR and DSC studies were performed it was found that there was no interaction between lornoxicam and polymers which used. All the physicochemical properties of prepared matrix-mini-tablets were found to be in normal limits. The percentage of drug content was found to be 99.60±0.07%. Our optimized matrix mini-tablets-filled-capsule formulation F30 released lornoxicam after a lag time of 5.02±0.92 hr, 95.48±0.65 % at the end of 8 hr and 99.90±0.83 % at the end of 12 hr. Stability was also found for this formulation as per the guidelines of International Conference on Harmonisation of Technical Requirements of Pharmaceuticals for Human Use. Conclusion: A novel colon targeted delivery system of lornoxicam was successfully developed by filling matrix-mini-tablets into an empty HPMC capsule shell for targeting early morning peak symptoms of rheumatoid arthritis. PMID:24967065

Mohd, Abdul Hadi; Raghavendra Rao, Nidagurthi Guggilla; Avanapu, Srinivasa Rao

2014-01-01

54

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

PubMed Central

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

Phaechamud, T.; Choncheewa, C.

2015-01-01

55

Solid Dispersion Matrix Tablet Comprising Indomethacin-PEG-HPMC Fabricated with Fusion and Mold Technique  

PubMed Central

The purpose of this study is to fabricate the polyethylene glycol matrix tablet by mold technique. Indomethacin and hydroxypropylmethylcellulose were used as model drug and polymer, respectively, in PEG matrix system. The physical and drug release characteristics of developed matrix tablet were studied. This inert carrier system comprising 7:3 polyethylene glycol 4000: polyethylene glycol 400 could effectively enhance the solubility of indomethacin and an addition of hydroxypropylmethylcellulose could sustain the drug release. Scanning electron microscope photomicrograph indicated the drug diffusion outward through the porous network of this developed matrix tablet into the dissolution fluid. Least square fitting the experimental dissolution data to the mathematical expressions (power law, first-order, Higuchi's and zero-order) indicated the drug release kinetics primarily as Fickian diffusion. Both the enhancement of drug dissolution and the prolongation of the drug release could be achieved for aqueous insoluble drug such as, indomethacin, by using polyethylene glycol-hydroxypropylmethylcellulose matrix system prepared with melting and mold technique. PMID:20502547

Mesnukul, A.; Yodkhum, K.; Phaechamud, T.

2009-01-01

56

EXPANDED STARCH AS A FLOATING DOSAGE MATRIX FOR THE CONTROLLED RELEASE OF MODEL DRUG COMPOUNDS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Starch-based materials were tested using model drug compounds to determine the feasibility of using starch as an oral floating dosage matrix. Oral controlled release systems require increased bio-availability, predictable release rates, and site-specific delivery. Starch and model drugs were compo...

57

Matrix tablets based on a carrageenan with the modified-release of sodium riboflavin 5'-phosphate.  

PubMed

Abstract The focus of this work was to produce modified-release monolithic matrix tablets containing sodium riboflavin 5'-phosphate (vitamin B2) as active pharmaceutical ingredient (API). Riboflavin 5'-phosphate is absorbed from the upper gastrointestinal tract by a specific transport mechanism. The aim of this work was the development of modified-release tablets from which most or the entire API can dissolve within 5?h. The dissolution was started in medium pH 1.2 (gastric juice) and finished in medium pH 4.5. The matrix former was iota-carrageenan combined with microcrystalline cellulose (MCC) and lactose in different ratios. Factorial design was used in this work so as to study the effects of the MCC/lactose ratio on the parameters of the tablets, and especially on the dissolution process. The dissolution data were subjected to statistical analysis, and the release profiles were fitted with different models. It was found that the MCC/lactose ratio influenced the quality of the tablets to a high degree. The Korsmeyer-Peppas model proved to characterize the total dissolution profile best, but fitting of the separate sections was also possible with a linear model. PMID:24758384

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

2014-04-24

58

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

PubMed

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

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

2011-08-01

59

Designing an extended release waxy matrix tablet containing nicardipine–hydroxy propyl ? cyclodextrin complex  

PubMed Central

Aim The current study aimed to prepare a sustained release tablet for a drug which has poor solubility in alkaline medium using complexation with cyclodextrin. Nicardipine hydrochloride (NC) a weak basic drug was chosen as a model drug for this study. Method Firstly the most suitable binary system NC-HP?CD was selected in order to improve drug solubility in the intestinal media and then embedding the complexed drug into a plastic matrix, by fusion method, consists of glycerol monostearate (GMS) as an inert waxy substance and polyethylene glycol 4000 (PEG4000) as a channeling agent, after that the final solid dispersion [(NC:HP?CD):GMS:PEG4000] which was prepared at different ratios was mixed with other excipients, avicel PH101, lactose, and talc, to get a tablet owning dissolution profile complying with the FDA and USP requirements for the extended release solid dosage forms. Results Infrared spectroscopy (IR), differential scanning colorimetry (DSC), polarized microscopy and X-ray diffractometry proved that the coevaporation technique was effective in preparing amorphous cyclodextrin complexes with NC and trapping of NC within the HP?CD cavity by dissolving both in ethanol and evaporate the solvent using a rotavapor at 65 °C. Dissolution profile of NC enhanced significantly in pH 6.8 from NC:HP?CD inclusion complex prepared by the rotavapor (t-test Student p < 0.05). The release of NC from tablet containing [(NC:HP?CD):GMS:PEG4000] [(1):0.75:0.5] (w/w/w) solid dispersion (F8) was complying with the FDA dissolution requirements for extended release dosage forms, and studying the kinetics of the release showed that the diffusional contribution is the major factor controlling the drug release from that formula. Conclusion The prepared waxy matrix tablet containing NC complexes with CD shows promising results as extended release tablets. PMID:23960765

Al-Zein, Hind; Sakeer, Khalil; Alanazi, Fars K.

2011-01-01

60

Design and evaluation of microporous membrane coated matrix tablets for a highly water soluble drug.  

PubMed

Microporous coated matrix tablet consists of a microporous membrane which is produced directly from a nonporous polymer coating during transit in the gastro-intestinal tract. In the present study, efforts have been made to develop and evaluate the in-vitro performance of a matrix embedded microporous controlled release system to deliver a drug with high aqueous solubility (> or =3 g/ml), high pK(a) (> or =9.0) and low molecular weight (<500 Da). The matrix embedded core tablets were prepared and coated using film former (2% w/w) and different pore formers (1-20% w/w of film former) such as plasticizer (PEG 4000), surfactant (Tween 80) and polysaccharide (Dextran) in a conventional coating pan. The tablets were evaluated for various physical parameters, coat tensile strength and in-vitro drug release characteristics. The ethyl cellulose films suppressed the initial burst effect in drug release more than cellulose acetate and polymethacrylates films. PEG 4000 was found to be most effective plasticizer and pore former in controlling drug release, followed by Tween 80 and dextran. The prepared formulations provided prolonged and zero-order drug release. PMID:20606356

Mishra, Madhusmita; Mishra, Brahmeshwar

2010-07-01

61

Formulation and evaluation of polyelectrolyte complex-based matrix tablet of Isosorbide Mononitrate  

PubMed Central

Introduction: The polyelectrolyte Complexes (PECs) are based on ionic cross-linking. They have been employed to prepare a sustained release matrix tablets. These systems are based upon the fact that their structure can entrap the drug within them. Isosorbide Mononitrate (ISMN) is an anti-anginal organic nitrate vasodilator used in the treatment of various cardiovascular disorders and prophylaxis of angina Pectoris, which is poorly absorbed from the upper GIT, hence CR formulation is desirable. Materials and Methods: Chitosan (CH)/Sodium alginate (SA), Guar gum (GG), and Xanthan gum (XG) were used as PECs, and were prepared using different proportions i.e., in 1:1 and 1:2 ratio. The optimum ratio of CH: SA, CH: GG and CH: XG was in the ratio was 1:2; these are formed due to electrostatic interaction between oppositely charged poly ions. These normally employ a hydrophilic matrix system. Matrix tablet of ISMN was formulated by using PECs as matrix forming agent by wet granulation technique. Results: The tablets were evaluated for hardness, wt variation, drug content, and in-vitro dissolution studies and found to be within limits. Release kinetics data indicated that ISMN released from the PECs-based matrix tablets of CH-SA, CH-GG and CH-XG CP in 1:1 and 1:2 ratio, followed Fickian and non-Fickian diffusion mechanism respectively. Thus, the drug release rate was extended for over a period of more than 12 h stability studies. There is no significant difference in the mean % drug released from formulation CH-X2 after storing for 3 months at 40°C/75% RH. The FT-IR spectra revealed that there was no interaction between polymers and drug, Statistical analysis showed a significant differences (P < 0.05) for the amount of ISMN released from the formulations (MXG) and formulations (CH-X2). Conclusion: Formulation CH-XG2 (1:2) showed better sustained release of highly water-soluble ISMN with the desired release rate. Thus, the formulated PECs-based matrix tablets seems to be a potential candidate for sustained drug delivery of highly soluble drug ISMN in the symptomatic therapy of angina pectoris. PMID:24678461

Syed, Iizhar Ahmed; Niveditha, P.; Ahmad, Ismail

2014-01-01

62

Preparation and in vitro evaluation of controlled release hydrophilic matrix tablets of ketorolac tromethamine using factorial design.  

PubMed

Controlled release matrix tablets of ketorolac tromethamine (KT) were prepared by direct compression technique using cellulose derivatives as hydroxypropylmethyl cellulose (HPMC), hydroxyethyl cellulose (HEC), and carboxymethyl cellulose (CMC) in different concentrations (10-20%). The effect of polymer type and concentration was investigated on drug release by 2(3) factorial design. For the quality control of matrix tablets, weight deviation, hardness, friability, diameter-height ratio, content uniformity of KT, and in vitro dissolution technique were performed. UV Spectrophotometric method was used to detection of KT in matrix tablets. This method was validated. Dissolution profiles of the formulations were plotted and evaluated kinetically. An increase in polymer content resulted with a slow release rate of drug as was expected. According to the dissolution results, tablets prepared with HPMC + HEC + CMC (F1 and F8) were found to be the most suitable formulation for KT. About 99.27% KT was released from F8 in 7 h. PMID:18686094

Genç, Lütfi; Jalvand, Esmaeil

2008-08-01

63

Drug release-modulating mechanism of hydrophilic hydroxypropylmethylcellulose matrix tablets: distribution of atoms and carrier and texture analysis.  

PubMed

Although release profiles of drug from hydrophilic matrices have been well recognized, the visual distribution of hydroxypropylmethylcellulose (HPMC) and atoms inside of internal structures of hydrophilic HPMC matrices has not been characterized. In this paper, drug release mechanism from HPMC matrix tablet was investigated based on the release behaviors of HPMC, physical properties of gelled HPMC tablet and atomic distributions of formulation components using diverse instruments. A matrix tablet consisting of hydroxypropyl methylcellulose (HPMC 6, 4,000 and 100,000 mPa·s), chlorpheniramine maleate (CPM) as a model and fumed silicon dioxide (Aerosil(®) 200) was prepared via direct compression. The distribution of atoms and HPMC imaging were characterized using scanning electron microscope (SEM)/ energy-dispersive X-ray spectroscopy (EDX), and near-infrared (NIR) analysis, respectively as a function of time. A texture analyzer was also used to characterize the thickness and maintenance of gel layer of HPMC matrix tablet. The HPMC matrix tablets showed Higuchi release kinetics with no lag time against the square root of time. High viscosity grades of HPMC gave retarded release rate because of the greater swelling and gel thickness as characterized by texture analyzer. According to the NIR imaging, low-viscosity-grade HPMC (6 mPa·s) quickly leached out onto the surface of the tablet, while the high-viscosity-grade HPMC (4000 mPa·s) formed much thicker gel layer around the tablet and maintained longer via slow erosion, resulting in retarded drug release. The atomic distribution of the drug (chlorine, carbon, oxygen), HPMC (carbon, oxygen) and silicon dioxide (silica, oxygen) and NIR imaging of HPMC corresponded with the dissolution behaviors of drug as a function of time. The use of imaging and texture analyses could be applicable to explain the release- modulating mechanism of hydrophilic HPMC matrix tablets. PMID:23855499

Park, Jun-Bom; Lim, Jisung; Kang, Chin-Yang; Lee, Beom-Jin

2013-12-01

64

Xanthan and galactomannan (from M. scabrella) matrix tablets for oral controlled delivery of theophylline.  

PubMed

Directly compressed theophylline tablets, containing commercial xanthan (X) (Keltrol) and a highly hydrophilic galactomannan (G) from the seeds of Mimosa scabrella (a brazilian leguminous tree called bracatinga) as release-controlling agents, were obtained. Gums were used at 4, 8, 12.5 and 25% (w/w), either alone or in mixture (X:G 1:1). During galactomannan extraction process, the biopolymer was dried in a scale up, by vacuum oven (VO) or spray dryer (SD). The in vitro drug release was evaluated at different time intervals during 8 h using apparatus 1 (USP 26) at 100 rpm. The pH of the dissolution medium (1.4) was changed to 4.0 and 6.8 after 2 and 3 h, respectively. Tablets containing G(SD) resulted in more uniform drug release than G(VO) ones, due to their smaller particle size. The drug release decreased with the increase of polymer concentration and all formulations at 25% w/w of gums showed excessive sustained release effect. The matrices made with alone X showed higher drug retention for all concentrations, compared with G matrices that released the drug too fast. The XG matrices were able to produce near zero-order drug release. The XG(SD) 8% tablets provided the required release rate (about 90% at the end of 8 h), with zero-order release kinetics. Tablets containing G(VO) in low concentration showed a complete erosion, while the others demonstrated fast hydration and swelling in contact with the dissolution medium. The release mechanism was a combination of diffusion and relaxation. The relative importance of these two processes varied with matrix composition. The XG(SD) 8% matrix showed higher contribution of polymer relaxation. PMID:15885450

Vendruscolo, C W; Andreazza, I F; Ganter, J L M S; Ferrero, C; Bresolin, T M B

2005-05-30

65

Preparation and in vitro evaluation of guar gum based triple-layer matrix tablet of diclofenac sodium  

PubMed Central

The objective of the present study was to design an oral controlled drug delivery system for sparingly soluble diclofenac sodium (DCL) using guar gum as triple-layer matrix tablets. Matrix tablet granules containing 30% (D1), 40% (D2) or 50% (D3) of guar gum were prepared by the conventional wet granulation technique. Matrix tablets of diclofenac sodium were prepared by compressing three layers one by one. Centre layer of sandwich like structure was incorporated with matrix granules containing DCL which was covered on either side by guar gum granule layers containing either 70, 80 or 87% of guar gum as release retardant layers. The tablets were evaluated for hardness, thickness, drug content, and drug release studies. To ascertain the kinetics of drug release, the dissolution profiles were fitted to various mathematical models. The in vitro drug release from proposed system was best explained by the Hopfenberg model indicating that the release of drug from tablets displayed heterogeneous erosion. D3G3, containing 87% of guar gum in guar gum layers and 50% of guar gum in DCL matrix granule layer was found to provide the release rate for prolonged period of time. The results clearly indicate that guar gum could be a potential hydrophilic carrier in the development of oral controlled drug delivery systems. PMID:23181081

Chavda, H.V.; Patel, M.S.; Patel, C.N.

2012-01-01

66

Formulation and in vitro evaluation of Eudragit S-100 coated naproxen matrix tablets for colon-targeted drug delivery system  

PubMed Central

The purpose of the present investigation was to prepare matrix tablets of naproxen using a hydrophobic polymer, i.e., Eudragit RLPO, RSPO, and combination of both, by wet granulation method. The tablets were further coated with different concentrations of Eudragit S-100, a pH-sensitive polymer, by dip immerse method. In vitro drug release studies of tablets were carried out in different dissolution media, i.e., 0.1 N HCl (pH 1.2), phosphate buffers pH 6.8 and 7.4, with or without rat cecal content. The swelling studies of the optimized formulation were carried out. The physicochemical parameters of all the formulations were found to be in compliance with the pharmacopoeial standards. The effect of dissolution medium on the surface of matrix tablet was determined by using Scanning Electron Microscopy technique. The stability studies of all formulations were performed as per ICH guidelines. The results demonstrated that the tablets coated with Eudragit S-100 (2% w/v) showed a sustained release of 94.67% for 24 h, but drug release increased to about 98.60% for 24 h in the presence of rat cecal content while the uncoated tablets released the drug within 5 h. With regard to release kinetics, the data were best fitted with the Higuchi model with non-Fickian drug release kinetics mechanism. The stability studies of tablets showed less degradation during accelerated and room temperature storage conditions for 6 months. The enteric-coated Eudragit S-100 coated matrix tablets of naproxen showed promising site-specific drug delivery in the colon region. PMID:23662280

Mehta, Rohit; Chawla, Anuj; Sharma, Pooja; Pawar, Pravin

2013-01-01

67

Formulation and in vitro evaluation of Eudragit S-100 coated naproxen matrix tablets for colon-targeted drug delivery system.  

PubMed

The purpose of the present investigation was to prepare matrix tablets of naproxen using a hydrophobic polymer, i.e., Eudragit RLPO, RSPO, and combination of both, by wet granulation method. The tablets were further coated with different concentrations of Eudragit S-100, a pH-sensitive polymer, by dip immerse method. In vitro drug release studies of tablets were carried out in different dissolution media, i.e., 0.1 N HCl (pH 1.2), phosphate buffers pH 6.8 and 7.4, with or without rat cecal content. The swelling studies of the optimized formulation were carried out. The physicochemical parameters of all the formulations were found to be in compliance with the pharmacopoeial standards. The effect of dissolution medium on the surface of matrix tablet was determined by using Scanning Electron Microscopy technique. The stability studies of all formulations were performed as per ICH guidelines. The results demonstrated that the tablets coated with Eudragit S-100 (2% w/v) showed a sustained release of 94.67% for 24 h, but drug release increased to about 98.60% for 24 h in the presence of rat cecal content while the uncoated tablets released the drug within 5 h. With regard to release kinetics, the data were best fitted with the Higuchi model with non-Fickian drug release kinetics mechanism. The stability studies of tablets showed less degradation during accelerated and room temperature storage conditions for 6 months. The enteric-coated Eudragit S-100 coated matrix tablets of naproxen showed promising site-specific drug delivery in the colon region. PMID:23662280

Mehta, Rohit; Chawla, Anuj; Sharma, Pooja; Pawar, Pravin

2013-01-01

68

Pharmaceutical applications of shellac: moisture-protective and taste-masking coatings and extended-release matrix tablets.  

PubMed

Shellac is a natural polymer, which is used as enteric coating material in pharmaceutical applications. The major objective of the present study was to investigate the potential of shellac for other purposes, namely to provide moisture-protective and taste-masking coatings as well as extended-release matrix tablets. The efficiency of shellac to achieve moisture protection and taste masking was compared with that of hydroxypropyl methylcellulose (HPMC), which is most frequently used for these purposes. Shellac-coated tablets showed lower water uptake rates than HPMC-coated systems at the same coating level. The stability of acetylsalicylic acid was higher in tablets coated with shellac compared with HPMC-coated systems, irrespective of the storage humidity. Therefore, lower shellac coating levels were required to achieve the same degree of drug protection. Shellac coatings effectively masked the unpleasant taste of acetaminophen tablets. Compared to HPMC, again lower coating levels were required to achieve similar effects. The resulting drug release in simulated gastric fluid was not significantly altered by the thin shellac coatings, which rapidly ruptured due to the swelling of the coated tablet core. In addition, shellac was found to be a suitable matrix former for extended-release tablets. The latter could be prepared by direct compression or via wet granulation using ethanolic or ammoniated aqueous shellac binder solutions. The resulting drug-release patterns could effectively be altered by varying different formulation and processing parameters. PMID:14570313

Pearnchob, N; Siepmann, J; Bodmeier, R

2003-09-01

69

[On the manufacture and testing of butaperazine matrix tablets with silicone varnish NH 30 as a structural substance (author's transl)].  

PubMed

It is reported of the manufacture and testing of matrix tablets containing butaperazine dihydrogen maleinate as a model substance and silicone varnish NH 30 as a structural constituent. On in vitro testing in artificial gstric juice (pH = 1.2), The drug was fully available when the tablets had been prepared by the method of separate granulation. Furthermore, the release of the drug was studied by means of the half-change method at different pH values, in artificial intestinal juice (pH = 7.5) and under sink conditions. The last-mentioned method is concerned with the drug transferred in vitro. Variations in pressing pressure and varnish concentration permit to prepare tablets of planned release characteristics. The release rates were higher in systems with n-heptane as the lipophil phase than in systems under non-sink conditions. This method is sensitive enough to differentiate among batches of tablets varying in drug release. PMID:6106210

Kala, H; Wendorff, D; Moldenhauer, H

1980-01-01

70

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

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

71

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

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

72

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

PubMed Central

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

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

2014-01-01

73

Formulation and evaluation of a novel matrix-type orally disintegrating Ibuprofen tablet.  

PubMed

Orally disintegrating tablets (ODTs) are capable of turning quickly into a liquid dosage form in contact with the saliva, thus possessing the advantages of both the solid dosage forms particularly stability and liquid dosage forms specially ease of swallowing and pre-gastric absorption of drug. The aim of this study was to prepare a novel matrix-type buccal fast disintegrating ibuprofen tablet formulation using special polymers, water soluble excipients, super-disintegrants and quickly soluble granules. For this purpose different tablet formulations of ibuprofen were prepared. The amount of ibuprofen in each formulation was 100 mg. Eight groups of formulation were prepared (A-H series), accounting for a total number of 45 formulations. Formulations prepared were examined in terms of different physicochemical tests including powder/granule flowability, appearance, thickness, uniformity of weight, hardness, friability and disintegration time. Results of formulation F22a (in series F), was found to be acceptable, making it the chosen formulation for further studies. Then, by adding various flavorants and sweeteners to this formulation, complementary series of formulations, named G and H, were prepared. Following the comparison of their taste with each other through asking 10 volunteers, the most suitable formulation regarding the taste, being formulation F22s, was chosen as the ultimate formulation. This formulation had PVP, ibuprofen and croscarmellose as the intra-granular components and xylitol and saccharin as the extra-granular ingredients. Formulation F22s was found to be acceptable in terms of physicochemical tests conducted, showing quick disintegration within the buccal cavity, appropriate hardness and rather low friability. Hence formulation F22s was selected as the final formulation. PMID:24250378

Tayebi, Hoda; Mortazavi, Seyed Alireza

2011-01-01

74

Formulation Development and Stability Studies of Norfloxacin Extended-Release Matrix Tablets  

PubMed Central

The aim of this research was to develop a new hydrophilic matrix system containing norfloxacin (NFX). Extended-release tablets are usually intended for once-a-day administration with benefits to the patient and lower discontinuation of the therapy. Formulations were developed with hydroxypropylmethylcellulose or poly(ethylene oxide) as hydrophilic polymers, with different molecular weights (MWs) and concentrations (20 and 30%). The tablets were found to be stable (6 months at 40 ± 2°C and 75 ± 5% relative humidity), and the film-coating process is recommended to avoid NFX photodegradation. The dissolution profiles demonstrated an extended-release of NFX for all developed formulations. Dissolution curves analyzed using the Korsmeyer exponential equation showed that drug release was controlled by both drug diffusion and polymer relaxation or erosion mechanisms. A more erosion controlled system was obtained for the formulations containing lower MW and amount of polymer. With the increase in both MW and amount of polymer in the formulation, the gel layer became stronger, and the dissolution was more drug-diffusion dependent. Formulations containing intermediate MW polymers or high concentration (30%) of low MW polymers demonstrated a combination of extended and complete in vitro drug release. This way, these formulations could provide an increased bioavailability in vivo. PMID:24083235

Oliveira, Paulo Renato; Klein, Lilian; Sangoi, Maximiliano da Silva; Bernardi, Larissa Sakis; Silva, Marcos Antônio Segatto

2013-01-01

75

In vitro release of sodium diclofenac from a central core matrix tablet aimed for colonic drug delivery  

Microsoft Academic Search

The present study was aimed at developing a novel sodium diclofenac formulation for colonic release. The proposed delivery system consisted in a polymeric matrix tablet containing a drug central core purposely designed for obtaining a time-controlled release profile characterized by an initial phase of lag-time followed by a controlled release phase, according to zero order kinetics. The spheric central core

Mar??a Luisa González-Rodr??guez; Francesca Maestrelli; Paola Mura; Antonio Mar??a Rabasco

2003-01-01

76

Drug release kinetics and fronts movement studies from methyl methacrylate (MMA) copolymer matrix tablets: effect of copolymer type and matrix porosity  

Microsoft Academic Search

Several methyl methacrylate (MMA) copolymers have recently been proposed as an alternative for the formulation of controlled-release matrix tablets. Copolymers were synthesised by free radical copolymerisation of methyl methacrylate with starch or cellulose derivatives and were alternatively dried by oven or freeze-drying techniques. Both the chemical composition and the drying technique were demonstrated to have a considerable influence on the

C Ferrero; I Bravo; M. R Jiménez-Castellanos

2003-01-01

77

In vitro Release Kinetic Study of Theophylline from Eudragit RS PO and Eudragit RL PO Matrix Tablets  

E-print Network

ABSTRACT: The aim of the present study was to investigate the release kinetics of theophylline from permeable acrylic polymer matrix tablets. Matrix tablets were prepared by direct compression method using Eudragit RS PO and Eudragit RL PO. Two batches of matrix tablets were prepared. Only Eudragit RS PO was used in the first batch, and in the second batch both Eudragit RS PO and Eudragit RL PO were used as the rate retarding polymers in different proportions. The variation of hardness was insignificant in batches. Drug release was investigated by using USP basket method and the results of release rates were analyzed by using correlation coefficient value of Zero order release plot & Higuchi plot and exponent value of Bi-exponential release profile. Theophylline tablets having only Eudragit RS PO showed comparatively slow release but release rate improved significantly as seen in formulations containing Eudragit RL PO and Eudragit RS PO. It was also revealed that, in all cases the release of theophylline followed mixed release kinetics where Zero order release kinetics was predominant.

Apurba Sarker Apu; Atiqul Haque Pathan; Golam Kibria; Reza-ul Jalil

78

Predicting the drug concentration in starch acetate matrix tablets from ATR-FTIR spectra using multi-way methods.  

PubMed

The amounts of drug and excipient were predicted from ATR-FTIR spectra using two multi-way modelling techniques, parallel factor analysis (PARAFAC) and multi-linear partial least squares (N-PLS). Data matrices consisted of dissolved and undissolved parallel samples having different drug content and spectra, which were collected at axially cut surface of the flat-faced matrix tablets. Spectra were recorded comprehensively at different points on the axially cut surface of the tablet. The sample drug concentrations varied between 2 and 16% v/v. The multi-way methods together with ATR-FTIR spectra seemed to represent an applicable method for the determination of drug and excipient distribution in a tablet during the release process. The N-PLS calibration method was more robust for accurate quantification of the amount of components in the sample whereas the PARAFAC model provided approximate relative amounts of components. PMID:17606000

Matero, Sanni; Pajander, Jari; Soikkeli, Anne-Marie; Reinikainen, Satu-Pia; Lahtela-Kakkonen, Maija; Korhonen, Ossi; Ketolainen, Jarkko; Poso, Antti

2007-07-01

79

Insights into the mechanisms of chitosan-anionic polymers-based matrix tablets for extended drug release.  

PubMed

The aim of this study was to investigate drug release mechanisms from physical mixtures of chitosan-anionic polymers-based matrix tablets and to obtain a comprehensive understanding about release characteristics. Six types of anionic polymers (i.e., Eudragit(®) L100, sodium alginate, carrageenan, carboxymethylcellulose sodium, carbomer and xanthan gum) and two model drugs (i.e., theophylline and metoprolol succinate) with varied solubility were chosen. Texture analyzer, differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) were applied to better understand drug release mechanisms. In vitro release experiments were conducted in a pH-changing medium to simulate the physiological condition of the gastrointestinal tract. Interestingly, a common phenomenon was observed in all the CS-anionic polymers-based matrix tablets investigated here, that is, the inner layer of the swollen tablets was coated by CS-anionic polymer polyelectrolyte complexes (PEC)-based film formed by self-assembly. Formation of the in situ self-assembled film was further confirmed by texture analysis, DSC, and FTIR. It was further identified that properties of the film were influenced by the characteristics of anionic polymers and the physiological conditions of the gastrointestinal tract. Moreover, this novel structure could alter swelling and erosion-based release mechanisms of the tablets. In addition, drug release characteristics from CS-anionic polymer systems depended on the properties of anionic polymers and the drug solubility. In conclusion, our studies may broaden current views on cationic polymer-anionic polymer-based oral matrix tablets for extended release. PMID:25290814

Li, Liang; Wang, Linlin; Li, Jinfeng; Jiang, Shan; Wang, Yitong; Zhang, Xin; Ding, Jiaojiao; Yu, Tongya; Mao, Shirui

2014-12-10

80

Ultrasound transmission technique as a potential tool for physical evaluation of monolithic matrix tablets.  

PubMed

The aim of this study was to investigate the effects of tablet porosity and particle size fraction of compacted Starch acetate powders, with and without model drug caffeine, on acoustic properties of tablets. The ultrasound velocity was determined from the transmission measurements. Tablets of starch acetate (SA DS 2.7) powder with two particle size fractions of 0-53 and 0-710 microm were compressed with a compaction simulator. Porosities of tablets varied in the range from 12% to 43% for both particle size fractions. Strong associations were found between the ultrasound velocity and physical properties of the tablets such as porosity and particle size fraction. Interestingly, ultrasound velocity was practically insensitive to inclusion of the model drug caffeine with the concentrations used. Based on this study ultrasound transmission method is a potential non-destructive tool for studying structural changes of tablets and other solid dosage forms. PMID:18446491

Hakulinen, M A; Pajander, J; Leskinen, J; Ketolainen, J; van Veen, B; Niinimäki, K; Pirskanen, K; Poso, A; Lappalainen, R

2008-01-01

81

The application of generalized regression neural network in the modeling and optimization of aspirin extended release tablets with Eudragit ® RS PO as matrix substance  

Microsoft Academic Search

The objective of this work is to use a generalized regression neural network (GRNN) in the design of extended-release aspirin tablets. As model formulations, 10 kinds of aspirin matrix tablets were prepared. Eudragit® RS PO was used as matrix substance. The amount of Eudragit® RS PO and compression pressure were selected as causal factors. In-vitro dissolution–time profiles at four different

Svetlana Ibri?; Milica Jovanovi?; Zorica Djuri?; Jelena Paroj?i?; Ljiljana Solomun

2002-01-01

82

Conceptuation, formulation and evaluation of sustained release floating tablets of captopril compression coated with gastric dispersible hydrochlorothiazide using 23 factorial design  

PubMed Central

Ambulatory blood pressure monitoring is regarded as the gold standard for hypertensive therapy in non-dipping hypertension patients. A novel compression coated formulation of captopril and hydrochlorothiazide (HCTZ) was developed in order to improve the efficacy of antihypertensive therapy considering the half-life of both drugs. The synergistic action using combination therapy can be effectively achieved by sustained release captopril (t1/2= 2.5 h) and fast releasing HCTZ (average t1/2= 9.5 h). The sustained release floating tablets of captopril were prepared by using 23 factorial design by employing three polymers i.e., ethyl cellulose (EC), carbopol and xanthan gum at two levels. The formulations (CF1-CF8) were optimized using analysis of variance for two response variables, buoyancy and T50%. Among the three polymers employed, the coefficients and P values for the response variable buoyancy and T50% using EC were found to be 3.824, 0.028 and 0.0196, 0.046 respectively. From the coefficients and P values for the two response variables, formulation CF2 was optimized, which contains EC polymer alone at a high level. The CF2 formulation was further compression coated with optimized gastric dispersible HCTZ layer (HF9). The compression coated tablet was further evaluated using drug release kinetics. The Q value of HCTZ layer is achieved within 20 min following first order release whereas the Q value of captopril was obtained at 6.5 h following Higuchi model, from which it is proved that rapid release HCTZ and slow release of captopril is achieved. The mechanism of drug release was analyzed using Peppas equation, which showed an n >0.90 confirming case II transportation mechanism for drug release. PMID:25006552

Sirisha, Pathuri Lakshmi; Babu, Govada Kishore; Babu, Puttagunta Srinivasa

2014-01-01

83

Conceptuation, formulation and evaluation of sustained release floating tablets of captopril compression coated with gastric dispersible hydrochlorothiazide using 2(3) factorial design.  

PubMed

Ambulatory blood pressure monitoring is regarded as the gold standard for hypertensive therapy in non-dipping hypertension patients. A novel compression coated formulation of captopril and hydrochlorothiazide (HCTZ) was developed in order to improve the efficacy of antihypertensive therapy considering the half-life of both drugs. The synergistic action using combination therapy can be effectively achieved by sustained release captopril (t1/2= 2.5 h) and fast releasing HCTZ (average t1/2= 9.5 h). The sustained release floating tablets of captopril were prepared by using 2(3) factorial design by employing three polymers i.e., ethyl cellulose (EC), carbopol and xanthan gum at two levels. The formulations (CF1-CF8) were optimized using analysis of variance for two response variables, buoyancy and T50%. Among the three polymers employed, the coefficients and P values for the response variable buoyancy and T50% using EC were found to be 3.824, 0.028 and 0.0196, 0.046 respectively. From the coefficients and P values for the two response variables, formulation CF2 was optimized, which contains EC polymer alone at a high level. The CF2 formulation was further compression coated with optimized gastric dispersible HCTZ layer (HF9). The compression coated tablet was further evaluated using drug release kinetics. The Q value of HCTZ layer is achieved within 20 min following first order release whereas the Q value of captopril was obtained at 6.5 h following Higuchi model, from which it is proved that rapid release HCTZ and slow release of captopril is achieved. The mechanism of drug release was analyzed using Peppas equation, which showed an n >0.90 confirming case II transportation mechanism for drug release. PMID:25006552

Sirisha, Pathuri Lakshmi; Babu, Govada Kishore; Babu, Puttagunta Srinivasa

2014-04-01

84

Sustained Release of a Water-Soluble Drug from Alginate Matrix Tablets Prepared by Wet Granulation Method  

Microsoft Academic Search

Alginate matrix tablet of diltiazem hydrochloride (DTZ), a water-soluble drug, was prepared using sodium alginate (SAL) and\\u000a calcium gluconate (CG) by the conventional wet granulation method for sustained release of the drug. The effect of formulation\\u000a variables like SAL\\/CG ratio, drug load, microenvironmental pH modulator, and processing variable like compression force on\\u000a the extent of drug release was examined. The

Sanchita Mandal; Sanat Kumar Basu; Biswanath Sa

2009-01-01

85

Effect of Quaternary Ammonium Carboxymethylchitosan on Release Rate In-vitro of Aspirin Sustained-release Matrix Tablets.  

PubMed

The aim of this study was to develop a derivative of chitosan as pharmaceutical excipient used in sustained-release matrix tablets of poorly soluble drugs. A water-soluble quaternary ammonium carboxymethylchitosan was synthesized by a two-step reaction with carboxymethylchitosan (CMCTS), decylalkyl dimethyl ammonium and epichlorohydrin. The elemental analysis showed that the target product with 10.27% of the maximum grafting degree was obtained. To assess the preliminary safety of this biopolymer, cell toxicity assay was employed. In order to further investigate quaternary ammonium carboxymethylchitosan application as pharmaceutical excipient, aspirin was chosen as model drug. The effect of quaternary ammonium CMCTS on aspirin release rate from sustained-release matrix tablets was examined by in-vitro dissolution experiments. The results showed that this biopolymer had a great potential in increasing the dissolution of poorly soluble drug. With the addition of CMCTS-CEDA, the final cumulative release rate of drug rose up to 90%. After 12 h, at the grade of 10, 20 and 50 cps, the drug release rate increased from 58.1 to 90.7%, from 64.1 to 93.9%, from 69.3 to 96.1%, respectively. At the same time, aspirin release rate from sustainedrelease model was found to be related to the amount of quaternary ammonium CMCTS employed. With the increase of CMCTS-CEDA content, the accumulated release rate increased from 69.1% to 86.7%. The mechanism of aspirin release from sustained-release matrix tablets was also preliminary studied to be Fick diffusion. These data demonstrated that the chitosan derivative has positive effect on drug release from sustained-release matrix tablets. PMID:24250627

Meng, Lingbin; Teng, Zhongqiu; Zheng, Nannan; Meng, Weiwei; Dai, Rongji; Deng, Yulin

2013-01-01

86

Preparation and in vitro/in vivo evaluation of dextran matrix tablets of budesonide in experimental ulcerative colitis in rats.  

PubMed

Budesonide is an anti-inflammatory drug of choice for treatment of ulcerative colitis which affects the rectum and a part of or the entire colon. Delivery of budesonide specifically to the colon would increase the efficacy of the drug and reduce the side-effects. The aim of this study was to develop an oral matrix system formulation for budesonide to deliver the major part of the drug to the colon for treatment of ulcerative colitis that has not been reported before. Directly compressed matrix tablets were prepared using different molecular weights of dextran and three ratios of drug-to-polymer. The physical properties of the tablets including weight variation, hardness, content uniformity, and release profile in HCl 0.1 N, phosphate buffer pH 7.4 and 6.8 containing 4% rat caecal and colonic contents were studied. The efficacy of the desired formulation was also evaluated against acetic acid-induced colitis in rats. Physical properties of the tablets were in the ranges recommended by official references. More than 10% of the drug was released in HCl 0.1 N and pH 7.4, while a very drastic increase was observed after exposure to pH 6.8 containing rat caecal contents. The efficacy of the selected formulation against rat-induced colitis was also increased in comparison to the non-targeted formulation of budesonide. In conclusion, matrix tablets with a 1:10 drug-to-dextran ratio with high molecular weight could deliver the drug specifically to the colon and are promising for treatment of ulcerative colitis. PMID:20954795

Ahmadi, Fatemeh; Varshosaz, Jaleh; Emami, Jaber; Tavakoli, Naser; Minaiyan, Mohsen; Mahzouni, Parvin; Dorkoosh, Farid

2011-02-01

87

An investigation into the drug release from ibuprofen matrix tablets with ethylcellulose and some poly-acrylate polymers.  

PubMed

This study was performed to achieve sustained-release Ibuprofen matrix tablets with a zero-order release kinetic while most of the previous formulations have shown Higuchi release kinetic. Considering the results from previous studies, ethyl cellulose, Carbopol 934P, Carbopol 974P, and Pemulen TR-1 were used at different amounts for preparation of the tablets by direct compression. The release profiles were studied in a two-stage release test using non-linear regression analysis. Carbopols 934P and 974P could not sustain the release adequately while Pemulen TR-1 had too strong sustaining effect. Therefore, combination formulations were considered and studied. The release profiles of ethyl cellulose formulation and the combination formulation consisting Carbopol 934P and Pemulen TR-1 best fitted in Higuchi model, although the zero-order model was not completely rejected. However, the kinetic model of release from the combination formulation consisting Carbopol 974P and Pemulen TR-1 changed to zero-order indicating the most constant release rate among formulations. This was speculated to be due to some erosion of the gel, as well as some interaction of the hydrophobic chain of Pemulen TR-1 with Ibuprofen. Therefore, this formulation is suggested for directly compressed sustained-release matrix tablets of Ibuprofen with a more constant release rate. PMID:24811808

Tabandeh, Hosseinali; Mortazavi, Seyed Alireza

2014-05-01

88

Influence of the components of Kollicoat SR film on mechanical properties of floating pellets from the point of view of tableting.  

PubMed

The influence of pellet core ingredients on pellet behaviour, e.g. during compression, is well known. In this study the influence of components of a Kollicoat SR polymer film on mechanical properties was investigated. The aim of this study was to evaluate the influence of polymer film components on the mechanical properties of the pellet as a whole, from the point of view of tableting. Tablets should disintegrate into undeformed pellets floating in this environment for 5-6 h, releasing the model drug--verapamil hydrochloride--if possible in a controlled way. The usefulness of texture analysis and work of compression measurement was also evaluated. Kollicoat SR in the form of a 30D aqueous dispersion was chosen as the main component of the polymer film. Polyvinyl pyrrolidone K-30 as a pore former, and propylene glycol, triethyl citrate and dibutyl sebacate plasticisers were selected as typical additives. The influence of different thickness of polymer film on behaviour during stress was also evaluated. After coating the cores with a 20 microm Kollicoat SR dispersion film, an increase in mechanical strength, in comparison to the pellet core, was observed (2.74 to 3.34 mJ). Addition of porophor increased the work of compression by 50% to 5.1 mJ. The investigation of the influence of plasticiser on film properties proved that the kind of plasticiser used in the polymer film had no effect on the mechanical properties of the film or pellets. Only in the case of the film with triethyl citrate was no distinct of the pellet core found. Pellets coated both with films with triethyl citrate and with dibutyl sebacate, in contrast to pellets with a film coating with propylene glycol, showed a significant decrease of the dissolution rate of verapamil hydrochloride (20, 10 and 40% at 6 hours, respectively). It is possible to compress pellets with a 50 microm polymer film without affecting the dissolution rate, as was confirmed during release studies. When using Kollicoat SR the most appropriate plasticizer seems to be triethyl citrate, and in this case a change of behavior during compression analysis by texture analyzer was observed. But so relationship was found between the type of plasticizer and the work needed to obtain a given deformation. PMID:18972835

Lunio, R; Sawicki, W

2008-10-01

89

Roller compaction of hydrophilic extended release tablets-combined effects of processing variables and drug/matrix former particle size.  

PubMed

The present study shows that roller compaction (RC) can successfully be used as a granulation method to prepare hydroxypropyl methylcellulose (HPMC)-based extended release matrix tablets containing a high drug load, both for materials deforming mainly by fragmentation (paracetamol) as for those having mainly plastic deformation (ibuprofen). The combined effect of RC process variables and composition on the manufacturability of HPMC tablets was investigated. Standard wet granulation grade HPMC was compared with a larger particle size direct compressible HPMC grade. Higher roll pressure was found to result in larger paracetamol granules and narrower granule particle size distributions, especially for formulations containing smaller size HPMC. However, for ibuprofen, no clear effect of roll pressure was observed. High roll pressure also resulted in denser ribbon and less bypass fines during RC. Loss of compactibility was observed for granules compared to powder blends, which was found to be related to differences in granule porosity and morphology. Using the large-sized HPMC grade did in some cases result in lower tensile strength tablets but had the advantage to improve the powder flow into the roller compactor. This work also indicates that when the HPMC level lies near the percolation threshold, significant changes can occur in the drug release rate due to changes in other factors (raw material characteristics and processing). PMID:25273028

Heiman, Johanna; Tajarobi, Farhad; Gururajan, Bindhumadhavan; Juppo, Anne; Abrahmsén-Alami, Susanna

2015-04-01

90

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

PubMed Central

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

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

2012-01-01

91

Quality by Design approach to understand the physicochemical phenomena involved in controlled release of captopril SR matrix tablets.  

PubMed

The aim of this study is to obtain swelling controlled release matrix tablets of captopril using the Quality by Design methodology (ICH Q8) and to know the transport mechanisms involved in captopril release. To obtain the area of knowledge, the design of experiments studying the effect of two components (HPMC K15M and ethylcellulose) at different levels has been applied, with the captopril dissolution profile as the product's most important critical quality attribute (CQA). Different dissolution profiles have been obtained with the design of experiments performed, which is a key factor in the development of controlled release matrix tablets. Kinetic analysis according to the equations of Higuchi and Korsmeyer-Peppas demonstrates that the release mechanism is a mechanism of erosion when the whole percentage of the polymer is ethylcellulose, and a diffusion mechanism when the whole percentage of the polymer is HPMC K15M. The physico-chemical characteristics of the gel layer determine the release rate of captopril. The thickness of the gel layer, the porosity which is formed in the matrix upon contact with water, pore size, the swelling rate, the erosion rate of the matrix, and the physico-chemical characteristics of captopril, are factors related to the kinetic equations described and that allow us to predict the release mechanism of captopril. A new relationship of the kinetic equations governing the in vitro behavior with the physical characteristics of the gel layer of the different formulations has been established. This study shows that the size of water-filled pores and the degree of crosslinking between the chains of HPMC K15M of the matrix are related to the exponent n of the Korsmeyer-Peppas equation and the type of transport of the captopril from within the matrix to the dissolution medium, that is, if the transport is only through water-filled pores, or if a combination of diffusion occurs through water-filled pores with a transport through continuous polymeric networks. PMID:25445523

Saurí, J; Millán, D; Suñé-Negre, J M; Colom, H; Ticó, J R; Miñarro, M; Pérez-Lozano, P; García-Montoya, E

2014-12-30

92

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

Abstract 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

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

2014-05-01

93

Magnetic Resonance Imaging and Image Analysis for Assessment of HPMC Matrix Tablets Structural Evolution in USP Apparatus 4  

Microsoft Academic Search

Purpose  The purpose of the study was to present a methodology for the processing of Magnetic Resonance Imaging (MRI) data for the\\u000a quantification of the dosage form matrix evolution during drug dissolution. The results of the study were verified by comparison\\u000a with other approaches presented in literature.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  A commercially available, HPMC-based quetiapine fumarate tablet was studied with a 4.7T MR system.

Piotr Kulinowski; Przemys?aw Doro?y?ski; Anna M?ynarczyk; W?adys?aw P. W?glarz

2011-01-01

94

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

PubMed

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

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

2014-01-01

95

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

PubMed Central

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

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

2014-01-01

96

Design and Evaluation of Ethyl Cellulose Based Matrix Tablets of Ibuprofen with pH Modulated Release Kinetics  

PubMed Central

Controlled release preparations have been reported to reduce the gastro irritant and ulcerogenic effects of non steroidal antiinflammatory drugs. In the present study, an attempt was made to develop matrix tablet-based controlled release formulations of ibuprofen, using ethyl cellulose as the rate-controlling polymer. In order to prevent initial release of the drug in the acidic environment of the stomach, cellulose acetate phthalate was incorporated in the matrix in varying amounts. It was found that with increasing the proportion of ethyl cellulose in the matrix, the drug release was extended for 14-16 h. Incorporation of cellulose acetate phthalate in ethyl cellulose matrix provided very low initial release of the drug in the first 2-3 h followed by enhanced release rate in alkaline medium owing to the high solubility of cellulose acetate phthalate at basic pH which led to creation of a porous matrix. It was concluded that combination of cellulose acetate phthalate with ethyl cellulose in the matrix base can be an effective means of developing a controlled release formulation of ibuprofen with very low initial release followed with controlled release up to 14-16 h. PMID:21394255

Chandran, S.; Asghar, Laila F. A.; Mantha, Neelima

2008-01-01

97

Study on sustained-release metformin hydrochloride from matrix tablet: Influence of hydrophilic polymers and in vitro evaluation  

PubMed Central

The overall objective of the present work was to develop an oral sustained-release (SR) metformin tablet prepared by the direct compression method, using hydrophilic hydroxylpropylmethylcellulose (HPMC) and Guar gum polymer alone and in combination at different concentrations. Metformin hydrochloride (HCl), a biguanide, has a relatively short plasma half-life and low absolute bioavailability. All the batches were evaluated for thickness, weight variation, hardness and drug content uniformity and in vitro drug release. Mean dissolution time is used to characterize the drug release rate from a dosage form, and indicates the drug release-retarding efficiency of the polymer. The hydrophilic matrix of HPMC alone could not control the Metformin release effectively for 12 h whereas when combined with Guar gum, it could slow down the release of drug and, thus, can be successfully employed for formulating SR matrix tablets. Fitting the data to the Korsmeyer equation indicated that diffusion along with erosion could be the mechanism of drug release. Similarity factor ƒ2 values suggest that the test and reference profiles are identical. PMID:23071938

Wadher, Kamlesh J; Kakde, Rajendra B; Umekar, Milind J

2011-01-01

98

Synthesis, characterization and evaluation of methacrylamide grafted gellan as sustained release tablet matrix.  

PubMed

In the present study, the microwave induced synthesis of polymethacrylamide-grafted-gellan gum (PMaa-g-GG) was carried out by free radical initiation using cerric (IV) ammonium nitrate (CAN) as redox initiator. Concentrations of methacrylamide (Maa), CAN and microwave irradiation time were taken as variable synthetic parameters. The modified polysaccharide obtained from different synthetic conditions was then characterized by FTIR, CHN analysis, DSC and powder X-ray diffraction. The yield and extent of grafting were assessed by determining percentage grafting, percentage grafting efficiency, percentage conversion and these were correlated with elemental analysis. The acute oral toxicity study of modified polysaccharide was performed as per OECD guideline. Histological comparison of different organs between control and test animal showed no significant difference. Sustained release tablets of diclofenac sodium (DS) were prepared with modified gellan. In vitro dissolution study showed the tablets were capable of releasing the drug over a period of 8 h. PMID:25316428

Nandi, Gouranga; Patra, Poushali; Priyadarshini, Rosy; Kaity, Santanu; Ghosh, Lakshmi Kanta

2015-01-01

99

Quantifying the release of lactose from polymer matrix tablets with an amperometric biosensor utilizing cellobiose dehydrogenase.  

PubMed

The release of lactose (hydrophilic) from polymer tablets made with hydrophobically modified poly(acrylic acid) (HMPAA) have been studied and compared to the release of ibuprofen, a hydrophobic active substance. Lactose is one of the most used excipients for tablets, but lactose release has not been widely studied. One reason could be a lack of good analytical tools. A novel biosensor with cellobiose dehydrogenase (CDH) was used to detect the lactose release, which has a polydiallyldimethylammonium chloride (PDADMAC) layer that increases the response. A sample treatment using polyethylenimine (PEI) was developed to eliminate possible denaturants. The developed methodology provided a good approach to detect and quantify the released lactose. The release was studied with or without the presence of a model amphiphilic substance, sodium dodecyl sulphate (SDS), in the release medium. Ibuprofen showed very different release rates in the different media, which was attributed to hydrophobic interactions between the drug, the HMPAA and the SDS in the release medium. The release of hydrophilic lactose, which did not associate to any of the other components, was rapid and showed only minor differences. The new methodology provides a useful tool to further evaluate tablet formulations by a relatively simple set of experiments. PMID:24726632

Knöös, Patrik; Schulz, Christopher; Piculell, Lennart; Ludwig, Roland; Gorton, Lo; Wahlgren, Marie

2014-07-01

100

Effect of relative humidity during tabletting on matrix formation of hydrocolloids: densification behavior of cellulose ethers.  

PubMed

The aim of this research was to investigate the elastic-plastic deformation behavior of the cellulose ethers hydroxypropylmethylcellulose (HPMC), hydroxyethylmethylcellulose (HEMC), and sodium carboxymethylcellulose (NaCMC) at relative humidities (RH) of 38, 57, and 75% and assess how the release of drugs embedded in such matrices is affected by the inner structure of the tablets formed during tabletting. Sorption and desorption isotherms and glass transition temperature were determined between 32 and 75% RH. The materials were equilibrated at 38, 57, and 75% RH and tabletted to a range of graded maximum relative densities. Pressure-time and displacement-time curves were analyzed by use of the Heckel function and a modified Weibull function (pressure-time only). After equilibration at the different RHs, all materials were in the glassy state. The respective degrees of polymerization had negligible effect on the absolute content of water, the sorption isotherms, and finally the densification behavior. At 38% RH, NaCMC contains the same amount of water as HPMC and HEMC, but deforms less plastically than the latter. This is attributed to tight binding of the water of hydration in the former. With increasing RH, NaCMC becomes only a little more plastic than both HPMC and HEMC, although it contains more than twice the amount of water. The binding strength of water and its molecular mobility, not the amount, seems to determine the readiness for volume reduction under load. PMID:9532598

Picker, K M; Mielck, J B

1998-02-01

101

Formulation development and evaluation of Diltiazem HCl sustained release matrix tablets using HPMC K4M and K100M.  

PubMed

The aim of this study was to develop a sustained release hydrophilic matrix tablet of Diltiazem HCl and evaluates the effect of formulation variables (e.g. lubricant, binder, polymer content and viscosity grades of HPMC) on drug release. Twelve different formulations (F1-F12) were prepared by direct compression. The results of the physical parameters and assay were found to be within the acceptable range. Rate of drug release was found to be slow as the fraction of the polymer was increased from 20-50%. The drug release rate from tablets containing K4M was effectively controlled by increasing the talc concentration, whereas the burst effect was reduced by increasing binder content. The drug release was higher with K4M as compare to K100M. Model-dependent and independent methods were used for data analysis and the best results were observed for K4M in Higuchi (R(2)=0.9903-0.9962) and K100M in Baker and Lonsdale (R(2)=0.9779-0.9941). The release mechanism of all formulations was non-Fickian. F7 (50% K4M, 2% talc, 10% Avicel PH101) and F11 (40% K100M) were very close to targeted release profile. F12 (50% K100M) exhibited highest degree of swelling and lowest erosion. The f1 and f2 test were performed taking F11 as a reference formulation. PMID:23811439

Qazi, Faaiza; Shoaib, Muhammad Harris; Yousuf, Rabia Ismail; Qazi, Tanveer Mustafa; Mehmood, Zafar Alam; Hasan, S M Farid

2013-07-01

102

The effect of polymer properties on direct compression and drug release from water-insoluble controlled release matrix tablets.  

PubMed

The objective of this study was to identify and evaluate key polymer properties affecting direct compression and drug release from water-insoluble matrices. Commonly used polymers, such as Kollidon(®) SR, Eudragit(®) RS and ethyl cellulose, were characterized, formulated into tablets and compared with regard to their properties in dry and wet state. A similar site percolation threshold of 65% v/v was found for all polymers in dry state. Key parameters influencing polymer compactibility were the surface properties and the glass transition temperature (T(g)), affecting polymer elasticity and particle size-dependent binding. The important properties observed in dry state also governed matrix characteristics and therefore drug release in wet state. A low T(g) (Kollidon(®) SRmatrix integrity (Eudragit(®) RSmatrix systems. PMID:24746409

Grund, Julia; Koerber, Martin; Walther, Mathias; Bodmeier, Roland

2014-07-20

103

Effect of formulation parameters and drug-polymer interactions on drug release from starch acetate matrix tablets.  

PubMed

The aim of this study was to determine, whether interactions between a drug and hydrophobic polymer matrix are present, and if so, how they affect the drug release. In addition, the most important formulation parameters, for example porosity or structure of the tablet, which have the greatest impact on drug release, were defined. Six different drug compounds, that is allopurinol, acyclovir, metronidazole, paracetamol, salicylamide and theophylline, were used in different formulations with hydrophobic starch acetate (DS 2.7) as a matrix forming polymer. Results indicate that the formulation parameters describing directly or indirectly the structure of the matrix, such as porosity, compaction force and the particle size fraction of the filler-binder, have the strongest impact on drug release. The contribution of drug property based variables is not as high as formulation parameters, but they cannot be overlooked. The contribution of water solubility and dissolution rate of the compound are obvious, but there are other significant parameters, which describe the hydrophobic and hydrophilic regions of the molecule, that also affect the drug release. This can be seen especially with the salicylamide: compound which appears to have a strong and sufficiently high hydrophobic region that interacts with starch acetate and impairs the drug release. PMID:19177516

Pajander, Jari; Korhonen, Ossi; Laamanen, Maria; Ryynänen, Eeva-Leena; Grimsey, Ian; van Veen, Bert; Ketolainen, Jarkko

2009-10-01

104

Regulating Drug Release Behavior and Kinetics from Matrix Tablets Based on Fine Particle-Sized Ethyl Cellulose Ether Derivatives: An In Vitro and In Vivo Evaluation  

PubMed Central

The design and fabrication of sustained/controlled release dosage forms, employing new excipients capable of extending/controlling the release of drugs from the dosage forms over prolonged periods, has worked well in achieving optimally enhanced therapeutic levels of the drugs. In this sense, the objective of this study was to investigate the suitability of selected cellulose ether derivatives for use in direct compression (DC) and as efficient drug release controlling agents. Controlled release matrix tablets of ciprofloxacin were prepared at different drug-to-polymer (D?:?P) ratios by direct compression using a fine particle sized ethylcellulose ether derivative (ETHOCEL Standard Premium 7FP) as rate controlling polymer. The tablets obtained were evaluated for various physico-chemical characteristics and in-vitro drug release studies were conducted in phosphate buffer (pH 7.4) using PharmaTest dissolution apparatus at constant temperature of 37°C ± 0.1. Similarity factor f2 was employed to the release profiles of test formulations and were compared with marketed ciprofloxacin conventional tablets. Drug release mechanism and the kinetics involved were investigated by fitting the release profile data to various kinetic models. It was found that with increasing the proportion of ethylcellulose ether derivative in the matrix, the drug release was significantly extended up to 24 hours. The tablets exhibited zero order or nearly zero order drug transport mechanism. In vivo drug release performance of the developed controlled release tablets and reference conventional tablets containing ciprofloxacin were determined in rabbit serum according to randomized two-way crossover study design using High Performance Liquid Chromatography. Several bioavailability parameters of both the test tablets and conventional tablets including Cmax?, Tmax? and AUC0-t were compared which showed an optimized Cmax? and Tmax? (P < 0.05). A good correlation was obtained between in vitro drug release and in vivo drug absorption with correlation value (R2 = 0.934). Relative bioavailability was found to be 93%. Reproducibility of manufacturing process and accelerated stability of the developed tablets were performed in stability chamber at 40 ± 2°C and 75 ± 5% relative humidity for a period of 6 months and were found to be stable throughout the stability period. PMID:22649325

Shah, Kifayat Ullah; Khan, Gul Majid

2012-01-01

105

Invivo absorption behaviour of theophylline from starch-methyl methacrylate matrix tablets in beagle dogs.  

PubMed

This study evaluates in vivo the drug absorption profiles from potato starch-methyl methacrylate matrices(*) using theophylline as a model drug. Healthy beagle dogs under fasting conditions were used for in vivo studies and plasma samples were analyzed by a fluorescence polarization immunoassay analysis (FPIA method). Non-compartmental and compartmental (population approach) analysis was performed to determine the pharmacokinetic parameters. The principle of superposition was applied to predict multiple dose plasma concentrations from experimental single dose data. An in vitro-in vivo correlation (IVIVC) was also assessed. The sustained absorption kinetics of theophylline from these formulations was demonstrated by comparison with two commercially available oral sustained-release theophylline products (Theo-Dur(®) and Theolair(®)). A one-compartment model with first order kinetics without lag-time best describes the absorption/disposition of theophylline from the formulations. Results revealed a theophylline absorption rate in the order FD-HSMMA?Theo-Dur(®)?OD-CSMMA>Theolair(®)?FD-CSMMA. On the basis of simulated plasma theophylline levels, a twice daily dosage (every 12h) with the FD-CSMMA tablets should be recommended. A Level C IVIVC was found between the in vitrot50% and the in vivo AUC/D, although further optimization of the in vitro dissolution test would be needed to adequately correlate with in vivo data. PMID:25476254

Fernández-Campos, F; Ferrero, C; Colom, H; Jiménez-Castellanos, M R

2015-01-30

106

[Study on application of bioassay method in drug-release evaluation in vitro of Salvia miltiorrhiza hydrophilic gel matrix tablets].  

PubMed

To investigate the feasible application of the bioassay method in the evaluation of traditional Chinese medicine sustained-release preparations, develop a rapid drug-release evaluation method in vitro for multi-component preparations, and replace the biological activity determination method characterizing the overall behavior with the existing drug-release evaluation method for single component, in order to give better instruction for sustained-release preparations. HPLC was adopted to determine dissolution media, drug releasing rates, and accumulative releasing of active ingredients (salvianolic acid B, protocatechuic aldehyde and rosmarinic acid) of Salvia Miltiorrhiza hydrophilic gel matrix tablets. The ultraviolet spectroscopy was adopted to determine the antioxidant activity of release media, and evaluate the correlation between the drug-time curve of various drug components and the drug-time curve of the total antioxidant activity. The correlation coefficient between the drug-release curve of various components and the drug-time curve of the total antioxidant activity was higher than the critical value r 0.898 (P < 0.001). This indicated that the drug-release curve of the three phenolic acids and the drug-time curve of the total antioxidant activity had a good correlation in different conditions, such as dissolution media, release rates and component ratios. The bioassay method for determination was feasible, simple and convenient for preparation quality evaluation and prescription design in the place of in vitro dissolution. PMID:24558869

Li, Dong-Ying; Liu, Xiao-Qian; Feng, Wei-Hong; Wang, Zhi-Min; Yi, Hong; Meng, Qing-Ju

2013-11-01

107

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

PubMed

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

Qiu, Shi; Li, Mingzhong

2015-02-01

108

Role of cyclodextrin complexation in felodipine-sustained release matrix tablets intended for oral transmucosal delivery: in vitro and ex vivo characterization.  

PubMed

The objective of the present research was two-fold: To characterize the produced inclusion complex of felodipine (FDP)-hydroxypropyl-?-cyclodextrin (HP?CD) utilizing lyophilization, and to develop and characterize a complexed sustained-release polymeric matrix tablets intended for buccal delivery. The phase-solubility diagram suggested an A(L) type system with 1:1 stoichiometry. Solid complexes prepared by physical mixing and lyophilization were characterized by thermal and non-thermal analytical techniques to corroborate the fact of complex formation. The sustained-release FDP tablets were produced by direct compression, and these drug or complex-loaded hydrophilic matrices were assessed for in vitro bioadhesion and release modulation, ex vivo permeation, and in vivo residence time. The in vitro drug release and ex vivo permeation across the porcine buccal membrane demonstrated that the matrix tablets containing FDP-HP?CD (FH5) solid complex exhibited a complete and sustained drug release pattern, and a significantly higher drug permeation (p?

Palem, Chinna Reddy; Kumar Battu, Sunil; Gannu, Ramesh; Yamsani, Vamshi Vishnu; Repka, Michael A; Yamsani, Madhusudan Rao

2012-01-01

109

Release behaviour of propranolol HCl from hydrophilic matrix tablets containing psyllium powder in combination with hydrophilic polymers.  

PubMed

The objective of this study was to investigate the release behaviour of propranolol hydrochloride from psyllium matrices in the presence hydrophilic polymers. The dissolution test was carried out at pH 1.2 and pH 6.8. Binary mixtures of psyllium and hydroxypropyl methylcellulose (HPMC) used showed that an increase in the percentage of HPMC in the binary mixtures caused a significant decrease in the release rate of propranolol. Psyllium-alginate matrices produced lower drug release as compared to when the alginate was the matrix former alone. When sodium carboxy methyl cellulose (NaCMC) was incorporated into the psyllium, the results showed that matrices containing the ratio of psyllium-NaCMC in the 1:1 ratio are able to slow down the drug release significantly as compared to matrices made from only psyllium or NaCMC as retardant agent suggesting that there could be a synergistic effect between psyllium and NaCMC. The double-layered tablets showed that the psyllium and HPMC in the outer shell of an inner formulation of psyllium alone had the greatest effect of protecting the inner core and thus producing the lowest drug release (DE?=?38%, MDT?=?93 min). A significant decrease in the value of n in Q?=?kt(n) from 0.70 to 0.51 as the psyllium content was increased from 50 to 150 mg suggests that the presence of psyllium in HPMC matrices affected the release mechanism. Psyllium powder had the ability in the combination with other hydrophilic polymers to produce controlled release profiles. Care and consideration should as such be taken when formulating hydrophilic matrices in different combinations. PMID:21918920

Siahi-Shadbad, Mohammad R; Asare-Addo, Kofi; Azizian, Kakali; Hassanzadeh, Davoud; Nokhodchi, Ali

2011-12-01

110

Development of Controlled-Release Matrix Tablet of Risperidone: Influence of Methocel®- and Ethocel®Based Novel Polymeric Blend on In Vitro Drug Release and Bioavailability  

Microsoft Academic Search

Controlled-release (CR) matrix tablet of 4 mg risperidone was developed using flow bound dry granulation–slugging method to\\u000a improve its safety profile and compliance. Model formulations F1, F2, and F3, consisting of distinct blends of Methocel® K100\\u000a LV-CR and Ethocel® standard 7FP premium, were slugged. Each batch of granules (250–1,000 ?m), obtained by crushing the slugs,\\u000a was divided into three portions after lubrication

Amir Badshah; Fazal Subhan; Khalid Rauf; Nadeem Irfan Bukhari; Kifayatullah Shah; Samiullah Khan; Zia Ahmed; Ihsanullah Khan

2011-01-01

111

Some variables affecting the characteristics of Eudragit E-sodium alginate polyelectrolyte complex as a tablet matrix for diltiazem hydrochloride.  

PubMed

Eudragit E (EE)-sodium alginate (SA) polyelectrolyte complexes (PECs) were prepared at pH 4 and 5.8 using sodium alginate of high (SAH) and low viscosity (SAL). The optimum EE-SA complexation mass ratio was determined using viscosity measurements. Interactions between EE and SA in PECs were characterized by Fourier transform infra-red spectroscopy (FT-IR) and differential scanning calorimetry (DSC). Diltiazem hydrochloride (DTZ HCl) tablets were prepared using the prepared EE-SA PECs and their physical mixtures at different ratios as matrices. Tablets were evaluated for swelling characteristics and in vitro drug release. Tablets containing EE-SAH physical mixtures of ratios (1.5:1 and 1:3) as matrices were effective in achieving sustained release of DTZ HCl, where the percent drug released was significantly (p < 0.05) decreased compared to that from tablets either containing the same ratios of EE-SAL physical mixtures or the preformed EE- -SAH and EE-SAL PECs. PMID:24670354

Yusif, Rehab Mohammad; Abu Hashim, Irhan Ibrahim; El-Dahan, Marwa Salah

2014-03-01

112

Study the effect of formulation variables on drug release from hydrophilic matrix tablets of milnacipran and prediction of in-vivo plasma profile.  

PubMed

The objective of this study was to design oral controlled release (CR) matrix tablets of Milnacipran using hydroxypropyl methylcellulose (HPMC) as the retardant polymer and to study the effect of various formulation factors such as polymer proportion, polymer viscosity, compression force and also the pH of dissolution medium on the in-vitro release of drug. Two viscosity grade of HPMC (15?K and 100?K) were used in the proportion of 50, 100, 150 and 200?mg per CR tablet. In-vitro release rate was characterized using various model dependent approaches and model independent dissolution parameters [T50% and T80% dissolution time, mean dissolution time (MDT), mean residence time (MRT), dissolution efficiency (DE)]. The statistical analysis was performed on all the model independent approaches using student t test and ANOVA. Results were found that as polymer concentration (50?mg to 200?mg) and viscosity (15?K to 100?K) increases, the MDT, MRT, T50% and T80% extended significantly. Drug release rate was found to be significantly different at different hardness. In-vivo human plasma concentration--time profile was predicted from in-vitro release data using convolution method. Predicted human pharmacokinetic parameters shows that the design CR formulation has capability to sustained the plasma drug level of milnacipran. PMID:23931031

Singhvi, Gautam; Shah, Abhishek; Yadav, Nilesh; Saha, Ranendra N

2014-09-01

113

Increased bioavailability of primaquine using poly(ethylene oxide) matrix extended-release tablets administered to beagle dogs  

PubMed Central

Primaquine (PQ) is used for the radical cure of Plasmodium vivax malaria and can cause serious side effects in some individuals. The development of an extended-release dosage with poly(ethylene oxide) as a hydrophilic polymer has been investigated to improve drug efficacy and tolerability. The aim of this study was to evaluate in vivo a new extended-release formulation of PQ (60 mg). The formulation was administered to beagle dogs and plasma PQ concentrations were compared to a conventional immediate-release formulation of PQ (60 mg). The evaluation was carried out using a validated high-performance liquid chromatography method using solid-phase extraction. Total PQ exposure in beagle dogs was 2.2 times higher (area under curve of 12?193 versus 5678 ng h/ml) and the elimination half-life of PQ was a 19-fold greater (12.95 hours versus 0.68 hours) with the extended-release tablets compared with the immediate-release tablets. These findings suggest that the extended-release formulation of PQ merits further evaluation for the treatment of P. vivax malaria and/or chemoprophylaxis. PMID:22185941

Bertol, C D; Oliveira, P R; Kuminek, G; Rauber, G S; Stulzer, H K; Silva, M A S

2011-01-01

114

Preparation and in vitro characterization of a non-effervescent floating drug delivery system for poorly soluble drug, glipizide.  

PubMed

The aim of the present study was to formulate a non-effervescent floating drug delivery system of glipizide, a poorly water soluble drug. The solubility of glipizide was initially enhanced using a solid dispersion (SD) strategy with the help of hydrophilic carriers such as poloxamer, cyclodextrin, and povidone. The optimized core material/SD was further formulated into non-effervescent floating tablets (NEFT) by using matrix ballooning inducers, such as crospovidone and release retarding agents including HPMC and PEO. Poloxamer-based solid dispersions prepared by a solvent evaporation technique showed the highest dissolution rate (1 : 10 drug to carrier ratio) compared with all other dispersions. NEFT were evaluated for all physico-chemical properties including in vitro buoyancy, dissolution, and release rate. All of the tablets were found to be within pharmacopoeial limits and all of the formulations exhibited good floating behavior. The formulations (F2 and F3) were optimized based on their 12 h drug retardation with continuous buoyancy. The optimized formulations were characterized using FTIR and DSC and no drug and excipient interaction was found. In-vitro buoyancy and dissolution studies showed that non-effervescent floating drug delivery systems provide a promising method of achieving prolonged gastric retention time and improved bioavailability of glipizide. PMID:25850215

Meka, Venkata Srikanth; Pillai, Shreeni; Dharmalingham, Senthil Rajan; Sheshala, Ravi; Gorajana, Adinarayana

2015-01-01

115

Artificial neural networks in the modeling and optimization of aspirin extended release tablets with eudragit L 100 as matrix substance  

Microsoft Academic Search

The purpose of the present study was to model the effects of the concentration of Eudragit L 100 and compression pressure\\u000a as the most important process and formulation variables on the in vitro release profile of aspirin from matrix tables formulated\\u000a with Eudragit L 100 as matrix substance and to optimize the formulation by artificial neural network. As model formulations,

Svetlana Ibri?; Milica Jovanovi?; Zorica Djuri?; Jelena Paroj?i?; Slobodan D. Petrovi?; Ljiljana Solomun; Biljana Stupar

2003-01-01

116

Design and Optimization of Floating Drug Delivery System of Acyclovir  

PubMed Central

The purpose of the present work was to design and optimize floating drug delivery systems of acyclovir using psyllium husk and hydroxypropylmethylcellulose K4M as the polymers and sodium bicarbonate as a gas generating agent. The tablets were prepared by wet granulation method. A 32 full factorial design was used for optimization of drug release profile. The amount of psyllium husk (X1) and hydroxypropylmethylcellulose K4M (X2) were selected as independent variables. The times required for 50% (t50%) and 70% (t70%) drug dissolution were selected as dependent variables. All the designed nine batches of formulations were evaluated for hardness, friability, weight variation, drug content uniformity, swelling index, in vitro buoyancy, and in vitro drug release profile. All formulations had floating lag time below 3 min and constantly floated on dissolution medium for more than 24 h. Validity of the developed polynomial equation was verified by designing two check point formulations (C1 and C2). The closeness of predicted and observed values for t50% and t70% indicates validity of derived equations for the dependent variables. These studies indicated that the proper balance between psyllium husk and hydroxypropylmethylcellulose K4M can produce a drug dissolution profile similar to the predicted dissolution profile. The optimized formulations followed Higuchi's kinetics while the drug release mechanism was found to be anomalous type, controlled by diffusion through the swollen matrix. PMID:21694992

Kharia, A. A.; Hiremath, S. N.; Singhai, A. K.; Omray, L. K.; Jain, S. K.

2010-01-01

117

Tablet Weaving  

ERIC Educational Resources Information Center

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)

Kren, Margo

1976-01-01

118

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

PubMed

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

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

2014-12-01

119

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

PubMed

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

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

2009-04-01

120

Pharmacokinetics and analgesic effect of ketorolac floating delivery system.  

PubMed

Abstract Objectives: The efficacy of ketorolac tromethamine (KT) floating alginate beads as a drug delivery system for better control of KT release was investigated. The formulation with the highest drug loading, entrapment efficiency, swelling, buoyancy, and in vitro release would be selected for further in vivo analgesic effect in the mice and pharmacokinetics study in rats compared to the tablet dosage form. Methods: KT floating alginate beads were prepared by extrusion congealing technique. KT in plasma samples was analyzed using a UPLC MS/MS assay. Results: The percentage yield, drug loading and encapsulation efficiency were increased proportionally with the hydroxypropylmethyl cellulose (HPMC) polymer amount in the KT floating beads. A reverse relationship was observed between HPMC amount in the beads and the KT in vitro release rate. F3-floating beads were selected, due to its better in vitro results (continued floating for >8?h) than others. A longer analgesic effect was observed for F3 in fed mice as compared to the tablets. After F3 administration to rats, the Cmax (2.2?±?0.3?µg/ml) was achieved at ?2?h and the decline in KT concentration was slower. F3 showed a significant increase in the AUC (1.89 fold) in rats as compared to the tablets. Conclusion: KT was successfully formulated as floating beads with prolonged in vitro release extended to a better in vivo characteristic with higher bioavailability in rats. KT in floating beads shows a superior analgesic effect over tablets, especially in fed mice. PMID:24512312

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

2014-02-10

121

Floating numerals and floating quantifiers  

Microsoft Academic Search

This paper investigates the basic licensing conditions of the floating quantifier, e.g. all in The boys all took a card. It proposes a new analysis in which the quantificational operation of the floating quantifier is distinct from that of the quantifier local to a DP, e.g. all in All boys took a card, in the sense that the former takes

Mana Kobuchi-Philip

2007-01-01

122

Overview o floating point  

E-print Network

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

Biagioni, Edoardo S.

123

Floating Butterfly  

NSDL National Science Digital Library

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.

2014-09-12

124

Ice Floats  

NSDL National Science Digital Library

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.

125

Floating Boats  

ERIC Educational Resources Information Center

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

Waugh, Michael

2007-01-01

126

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

PubMed Central

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

Dey, Sanjay; Chattopadhyay, Sankha; Mazumder, Bhaskar

2014-01-01

127

On floats and float tests  

NASA Technical Reports Server (NTRS)

The principal source of information on float resistance is the model test. In view of the insuperable difficulties opposing any attempt at theoretical treatment of the resistance problem, particularly at attitudes which tend toward satisfactory take-off, such as the transitory stage to planing, the towing test is and will remain the primary method for some time.

Seewald, Friedrich

1931-01-01

128

FloatingPoint FloatingPoint  

E-print Network

Floating­Point for CS 267 February 8, 1996 11:50 am Slide 1 What can you learn about Floating for CS 267, ( Profs. J.W . Demmel of UCB & A. Edelman of MIT ) 8 Feb. 1996 #12; Floating­Point for CS 267 ... ) Integers Fixed­Point Floating­Point #12; Floating­Point for CS 267 February 8, 1996 11:50 am Slide 3

California at Berkeley, University of

129

Floating layer recovery apparatus  

Microsoft Academic Search

This patent describes an apparatus for recovery of a layer of a first underground liquid floating on a second underground liquid in a well. It comprises: first float means disposed in the well in the first liquid, the float means having an effective buoyancy such that it floats in the first liquid; second float means disposed in the well in

K. Newcomer; S. Richter

1991-01-01

130

Floating point o questions  

E-print Network

Floating point o questions o co-processor o SPARC instructions o example o double-floats o quad-floats o Intel floating point 1 #12; Floating Point Questions o why use sign/magnitude instead of 2's complement

Biagioni, Edoardo S.

131

Floating Boats  

NSDL National Science Digital Library

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.

Michael Waugh

2007-07-01

132

Direct analysis of 18 flavonol glycosides, aglycones and terpene trilactones in Ginkgo biloba tablets by matrix solid phase dispersion coupled with ultra-high performance liquid chromatography tandem triple quadrupole mass spectrometry.  

PubMed

Analysis and quality control of Ginkgo biloba have been comprehensively studied. However, little attention has been devoted to the simultaneous extraction and analysis of flavonols and terpene trilactones, especially for direct quantification of flavonol glycosides. This work described a rapid strategy for one-step extraction and quantification of the components. A matrix solid phase dispersion (MSPD) method was designed for the extraction of ginkgo ingredients and compared with the heat-reflux and ultrasonic extraction methods. An ultra-high performance liquid chromatography (UHPLC)-tandem-triple-quadrupole-mass spectrometry (QQQ-MS) method was developed for detection of the 18 components, including 10 original flavonol glycosides, 3 aglycones, and 5 lactones. Subsequently, the proposed strategy was used for the analysis of 12 G. biloba tablets. Results showed that MSPD produced comparable extraction efficiency but consumed less time and required lower solvent volumes compared with conventional methods. Without hydrolysis, the concentration detected was much closer to the original in the sample. The total flavonol glycoside contents in ginkgo tablets ranged from 3.59 to 125.21?gmg(-1), and the terpene trilactone varied from 3.45 to 57.8?gmg(-1) among different manufacturers. In conclusion, the proposed MSPD and UHPLC-QQQ-MS is rapid and sensitive in providing comprehensive profile of chemical constituents especially the genuine flavonol glycosides for improved quality control of ginkgo products. PMID:24876067

Liu, Xin-Guang; Yang, Hua; Cheng, Xiao-Lan; Liu, Lei; Qin, Yong; Wang, Qi; Qi, Lian-Wen; Li, Ping

2014-08-01

133

Floating apparatus for recovery of floating oil  

Microsoft Academic Search

The invention describes a device for recovering oil floating on the surface of water. The device is a floating vessel which is maneuverable at will in order effectively to recover all of an oil slick floating on the surface of the water. The device includes paddle wheel means to skim the oil from the surface of the water. The oil

G. Mascarin; S. P. Mellina

1981-01-01

134

Terahertz technology: a boon to tablet analysis.  

PubMed

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

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

2009-05-01

135

Floating layer recovery apparatus  

SciTech Connect

This patent describes an apparatus for recovery of a layer of a first underground liquid floating on a second underground liquid in a well. It comprises: first float means disposed in the well in the first liquid, the float means having an effective buoyancy such that it floats in the first liquid; second float means disposed in the well in the first liquid, the float means having an effective buoyancy such that it floats near the bottom of the first liquid, the second float means having top, side and bottom surfaces; an inlet means disposed on the second float surface for permitting entry of the first liquid; conduit means coupled to the inlet means and extending below the second float means; third float means disposed in the second liquid and having an effective buoyancy such that the third float means will remain submerged in the second liquid, the conduit means being coupled to the third float; the guide means for slidably connecting the second float between the first and third float means.

Newcomer, K.; Richter, S.

1991-03-12

136

Preparation and Characterization of a Gastric Floating Dosage Form of Capecitabine  

PubMed Central

Gastrointestinal disturbances, such as nausea and vomiting, are considered amongst the main adverse effects associated with oral anticancer drugs due to their fast release in the gastrointestinal tract (GIT). Sustained release formulations with proper release profiles can overcome some side effects of conventional formulations. The current study was designed to prepare sustained release tablets of Capecitabine, which is approved by the Food and Drug Administration (FDA) for the treatment of advanced breast cancer, using hydroxypropyl methylcellulose (HPMC), carbomer934P, sodium alginate, and sodium bicarbonate. Tablets were prepared using the wet granulation method and characterized such that floating lag time, total floating time, hardness, friability, drug content, weight uniformity, and in vitro drug release were investigated. The sustained release tablets showed good hardness and passed the friability test. The tablets' floating lag time was determined to be 30–200 seconds, and it floated more than 24 hours and released the drug for 24 hours. Then, the stability test was done and compared with the initial samples. In conclusion, by adjusting the right ratios of the excipients including release-retarding gel-forming polymers like HPMC K4M, Na alginate, carbomer934P, and sodium bicarbonate, sustained release Capecitabine floating tablet was formulated. PMID:24288681

Taghizadeh Davoudi, Ehsan; Ibrahim Noordin, Mohamed; Kadivar, Ali; Kamalidehghan, Behnam; Farjam, Abdoreza Soleimani; Akbari Javar, Hamid

2013-01-01

137

Design of Sustained Release Tablet Containing Fucoidan.  

PubMed

The study introduced a new therapeutic agent,fucoidan, which can offer potential medical treatments including anti-inflammatory and anti-coagulant activities, as well as anti-proliferative effects on cancer cells. Fucoidan was included in sustained release formulations expected for aneffective plasma drug concentration for approximately 24 h. The matrices based on the two polymers hydroxypropylmethycellulose (HPMC) and polyethylene oxide (PEO) were prepared with various ratios between the polymers and fucoidan. The dissolution profiles of various matrix tablets performed in enzyme-free simulated intestinal fluid (pH 6.8) for 24 h indicated a higher potential of PEO-based matrix tablets in sustaining release of fucoidan. The swelling and erosion of the tablets were also characterized to elucidate the difference among those dissolution profiles. PMID:25382179

Tran, Thao Truong-Dinh; Ngo, Dai Kieu-Phuong; Vo, Toi Van; Tran, Phuong Ha-Lien

2014-11-01

138

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

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

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

2015-04-01

139

Automatic Identification of Float Flowmeter's Float  

Microsoft Academic Search

According to the automatic verification of float flowmeter problems, we put forward a device, and it can acquire float height. An MVC - II - 1MM camera is used to capture flowmeter images, and saves them in computer in the form of BMP files. By some functions, such as the edge detection, filtering, binary, expansion, refined, etc, and other algorithms

Xiao-xuan Cao; Yu-ming Shen

2010-01-01

140

The Design of Floats  

NASA Technical Reports Server (NTRS)

Following a summary of the multiplicity of domestic and foreign floats and a brief enumeration of the requirements of floats, the essential form parameters and their effect on the qualities of floats are detailed. On this basis a standard float design is developed which in model families with varying length/beam ratio and angle of dead rise is analyzed by an experimental method which permits its best utilization on any airplane.

Sottorf, W

1938-01-01

141

Floating-Point (Applications  

E-print Network

Number Theory and Floating-Point Numbers (Applications de la th#19; eorie des nombres aux An Interview with the Old Man of Floating-Point, interview from William Kahan (Turing Award 1989) by Charles on Floating-Point Invertible Numbers, 2001, to appear in Theoretical Computer Science. Theorem 1. For r = 0; 1

Zimmermann, Paul

142

SOFAR floats for POLYMODE  

Microsoft Academic Search

The design of a neutrally buoyant float and associated tracking and support equipment developed for the POLYMODE experiment is described. Floats with a signaling range of 1500 Km and an endurance of 2-1\\/2 years signal via the deep sound channel to both land based receiving stations and moored, portable receivers. Recordings of float signals are collected and centrally processed, providing

Douglas C. Webb

1977-01-01

143

An understanding of modified release matrix tablets behavior during drug dissolution as the key for prediction of pharmaceutical product performance - case study of multimodal characterization of quetiapine fumarate tablets.  

PubMed

Motivation for the study was the lack of dedicated and effective research and development (R&D) in vitro methods for oral, generic, modified release formulations. The purpose of the research was to assess multimodal in vitro methodology for further bioequivalence study risk minimization. Principal results of the study are as follows: (i) Pharmaceutically equivalent quetiapine fumarate extended release dosage form of Seroquel XR was developed using a quality by design/design of experiment (QbD/DoE) paradigm. (ii) The developed formulation was then compared with originator using X-ray microtomography, magnetic resonance imaging and texture analysis. Despite similarity in terms of compendial dissolution test, developed and original dosage forms differed in micro/meso structure and consequently in mechanical properties. (iii) These differences were found to be the key factors of failure of biorelevant dissolution test using the stress dissolution apparatus. Major conclusions are as follows: (i) Imaging methods allow to assess internal features of the hydrating extended release matrix and together with the stress dissolution test allow to rationalize the design of generic formulations at the in vitro level. (ii) Technological impact on formulation properties e.g., on pore formation in hydrating matrices cannot be overlooked when designing modified release dosage forms. PMID:25701626

Kulinowski, Piotr; Woyna-Orlewicz, Krzysztof; Rappen, Gerd-Martin; Haznar-Garbacz, Dorota; W?glarz, W?adys?aw P; Doro?y?ski, Przemys?aw P

2015-04-30

144

Teaching with Tablet PC's  

Microsoft Academic Search

Tablet PC's are traditional notebook computers with the ability to process digital ink by writing with a stylus. They have recently attracted attention as a potential tool for educational use. This paper describes the author's experience using the Tablet PC to conduct a CS1 course and a software engineering (SWE) course. The SWE course consisted primarily of PowerPoint lectures while

Kenrick Mock

2004-01-01

145

Molecular dynamic simulations of ocular tablet dissolution.  

PubMed

Small tablets for implantation into the subconjunctival space in the eye are being developed to inhibit scarring after glaucoma filtration surgery (GFS). There is a need to evaluate drug dissolution at the molecular level to determine how the chemical structure of the active may correlate with dissolution in the nonsink conditions of the conjunctival space. We conducted molecular dynamics simulations to study the dissolution process of tablets derived from two drugs that can inhibit fibrosis after GFS, 5-fluorouracil (5-FU) and the matrix metalloprotease inhibitor (MMPi), ilomastat. The dissolution was simulated in the presence of simple point charge (SPC) water molecules, and the liquid turnover of the aqueous humor in the subconjunctival space was simulated by removal of the dissolved drug molecules at regular intervals and replacement by new water molecules. At the end of the simulation, the total molecular solvent accessible surface area of 5-FU tablets increased by 60 times more than that of ilomastat as a result of tablet swelling and release of molecules into solution. The tablet dissolution pattern shown in our molecular dynamic simulations tends to correlate with experimental release profiles. This work indicates that a series of molecular dynamic simulations can be used to predict the influence of the molecular properties of a drug on its dissolution profile and could be useful during preformulation where sufficient amounts of the drug are not always available to perform dissolution studies. PMID:24073784

Ru, Qian; Fadda, Hala M; Li, Chung; Paul, Daniel; Khaw, Peng T; Brocchini, Steve; Zloh, Mire

2013-11-25

146

The influence of polyamide 6,10 synthesis variables on the physicochemical characteristics and drug release kinetics from a monolithic tablet matrix.  

PubMed

This study investigated the influence of solute-solvent quotients on the physicochemical properties and release kinetics of two amitryptyline-loaded polyamide 6,10 (PA 6,10) monolithic matrices, Formulations A and B (FA and FB). The molecular mass, crystallinity, structural elucidation and thermo-transitions were assessed using mass spectrophotometry, X-ray diffraction, FTIR and DSC. Surface morphologies of the matrices and physicomechanical strength were captured using SEM and textural analysis. Drug release, distension and matrix erosion were evaluated using mathematical modeling. FA and FB displayed overall drug release fractions of 0.58 and 0.92 with 55% and 30% of matrix remaining over 24 hours, respectively. The indentation diameters (FA?=?1.51?mm; FB?=?2.39?mm), deformation energies (FA?=?0.02 J; FB?=?0.03 J) and Brinell Hardness Numbers (FA?=?17.88 N/mm²; FB?=?14.45 N/mm²) were divergent. SEM revealed irregular matrix surfaces with varying pore distributions. Minimal shifts in the structural backbone of PA 6,10 and semi-crystallinity was noted. Multiple reversible and irreversible thermal transitions with molar masses of FA?=?345.2?g/mol and FB?=?307.2?g/mol were obtained. Drug release supported by in vivo studies provided sustained plasma levels of amitryptyline (T(max)?=?24?±?0.5?h and 12?±?0.5?h; C(max)?=?0.024?±?0.003??g/mL and 0.036?±?0.002??g/mL for FA and FB, respectively) compared to a conventional formulation, Trepiline® (T(max)?=?4?±?0.5?h and C(max)?=?0.05?±?0.002??g/mL). The physicochemical properties of both formulations were reversibly influenced by differences in the PA 6,10 solute-solvent quotient employed during development. PMID:19922163

Kolawole, Oluwatoyin A; Pillay, Viness; Choonara, Yahya E; du Toit, Lisa C; Ndesendo, Valence M K

2010-12-01

147

Moving-load-induced vibrations of a moored floating bridge  

Microsoft Academic Search

The natural frequencies and mode shapes, and the coupled rigid-body (rolling) motion and elastic (flexural and torsional) vibration of a partial-catenary-moored floating bridge (in still water) subjected to a moving load are investigated. The mathematical model is obtained by simplifying one of the floating bridges in Lake Washington at Seattle, U.S.A. To derive the element mass matrix and stiffness matrix,

Jong-Shyong Wu; Po-Yun Shih

1998-01-01

148

Floating portable pump  

SciTech Connect

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 in an arrangement such that the engine causes rotation of the pump impeller to cause the pump to draw water from the well through its suction inlet and discharge water from the pump discharge.

Eberhardt, H. A.

1985-11-19

149

Calcification prevention tablets  

NASA Technical Reports Server (NTRS)

Citric acid tablets, which slowly release citric acid when flushed with water, are under development by the Navy for calcification prevention. The citric acid dissolves calcium carbonate deposits and chelates the calcium. For use in urinals, a dispenser is not required because the tablets are non-toxic and safe to handle. The tablets are placed in the bottom of the urinal, and are consumed in several hundred flushes (the release rate can be tailored by adjusting the formulation). All of the ingredients are environmentally biodegradable. Mass production of the tablets on commercial tableting machines was demonstrated. The tablets are inexpensive (about 75 cents apiece). Incidences of clogged pipes and urinals were greatly decreased in long term shipboard tests. The corrosion rate of sewage collection pipe (90/10 Cu/Ni) in citric acid solution in the laboratory is several mils per year at conditions typically found in traps under the urinals. The only shipboard corrosion seen to date is of the yellow brass urinal tail pieces. While this is acceptable, the search for a nontoxic corrosion inhibitor is underway. The shelf life of the tablets is at least one year if stored at 50 percent relative humidity, and longer if stored in sealed plastic buckets.

Lindsay, Geoffrey A.; Hasting, Michael A.; Gustavson, Michael A.

1991-01-01

150

Float Zone Workshop  

NASA Technical Reports Server (NTRS)

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.

Naumann, R. J.

1980-01-01

151

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

NASA Technical Reports Server (NTRS)

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!

2002-01-01

152

The influence of hydroxypropyl methylcellulose (HPMC) molecular weight, concentration and effect of food on in vivo erosion behavior of HPMC matrix tablets.  

PubMed

Four different hydrophilic matrix formulations based on hydroxypropyl methylcellulose (HPMC) were investigated for erosion properties in vivo. Three formulations contained a fixed amount of HPMC (40%) with varying proportions of two HPMC grades with different molecular weights (Methocel K100LV and K4M), and a fourth formulation contained a lower amount of the HPMC of lower molecular weight (20%). The effect of food on the in vivo erosion behavior was investigated on two formulations containing different contents of the same HPMC grade. The in vivo erosion behavior and gastrointestinal transit were investigated using magnetic marker monitoring (MMM). The in vitro and in vivo erosion-time profiles show that the erosion was strongly dependent on the composition of the formulation. The formulations containing a larger proportion of high molecular weight HPMC or higher content of HPMC exhibit relatively slower erosion rate and vice versa. In vivo erosion rates were significantly higher under postprandial administration as compared to fasted state administration. No rapid disintegration of any of the formulations (i.e. formulation failure that can potentially cause dose dumping) was observed. PMID:24818771

Jain, Arun Kumar; Söderlind, Erik; Viridén, Anna; Schug, Barbara; Abrahamsson, Bertil; Knopke, Christian; Tajarobi, Farhad; Blume, Henning; Anschütz, Maria; Welinder, Anette; Richardson, Sara; Nagel, Stefan; Abrahmsén-Alami, Susanna; Weitschies, Werner

2014-08-10

153

Microstructural investigation of tablet compaction and tablet pharmacological properties  

E-print Network

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. ...

Mao, Kangyi

2010-01-01

154

3D simulation of internal tablet strength during tableting.  

PubMed

This study presents a new approach to model powder compression during tableting. The purpose of this study is to introduce a new discrete element simulation model for particle-particle bond formation during tablet compression. This model served as the basis for calculating tablet strength distribution during a compression cycle. Simulated results were compared with real tablets compressed from microcrystalline cellulose/theophylline pellets with various compression forces. Simulated and experimental compression forces increased similarly. Tablet-breaking forces increased with the calculated strengths obtained from the simulations. The calculated bond strength distribution inside the tablets showed features similar to those of the density and pressure distributions in the literature. However, the bond strength distributions at the center of the tablets varied considerably between individual tablets. PMID:21541828

Siiriä, Simo Matti; Antikainen, Osmo; Heinämäki, Jyrki; Yliruusi, Jouko

2011-06-01

155

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

PubMed Central

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

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

2014-01-01

156

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

PubMed

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

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

2014-06-01

157

Effect of ionic crosslink on the release of metronidazole from partially carboxymethylated guar gum tablet.  

PubMed

Partially carboxymethylated guar gum (PCMGG) was crosslinked in situ by Ca(2+) ions during wet massing step of tablet preparation. The resulting tablets were evaluated for the effect of the extent of crosslinking on drug release and matrix swelling. Increase in the concentration of Ca(2+) ions increased the viscosity of gel layer and reduced the water penetration velocity into the matrix with subsequent decrease in swelling of the tablets and drug release. Beyond a certain concentration of Ca(2+) ions, the viscosity of the gel layer decreased and the drug release rate increased primarily due to erosion of the matrix. The mechanism of drug release appeared to be non-Fickian or anomalous transport. The release data also best fitted in zero order equation. The model drug, metronidazole, was compatible with the matrix materials as evident from instrumental analyses. Such formulation may provide flexibility in achieving the desired drug release rate from crosslinked matrix tablets. PMID:24721097

Singh, Rakesh; Maity, Siddhartha; Sa, Biswanath

2014-06-15

158

Desktop 3D printing of controlled release pharmaceutical bilayer tablets.  

PubMed

Three dimensional (3D) printing was used as a novel medicine formulation technique for production of viable tablets capable of satisfying regulatory tests and matching the release of standard commercial tablets. Hydroxypropyl methylcellulose (HPMC 2208) (Methocel™ K100M Premium) and poly(acrylic acid) (PAA) (Carbopol(®) 974P NF) were used as a hydrophilic matrix for a sustained release (SR) layer. Hypromellose(®) (HPMC 2910) was used as a binder while microcrystalline cellulose (MCC) (Pharmacel(®) 102) and sodium starch glycolate (SSG) (Primojel(®)) were used as disintegrants for an immediate release (IR) layer. Commercial guaifenesin bi-layer tablets (GBT) were used as a model drug (Mucinex(®)) for this study. There was a favourable comparison of release of the active guaifenesin from the printed hydrophilic matrix compared with the commercially available GBT. The printed formulations were also evaluated for physical and mechanical properties such as weight variation, friability, hardness and thickness as a comparison to the commercial tablet and were within acceptable range as defined by the international standards stated in the United States Pharmacopoeia (USP). All formulations (standard tablets and 3D printed tablets) showed Korsmeyer-Peppas n values between 0.27 and 0.44 which indicates Fickian diffusion drug release through a hydrated HPMC gel layer. PMID:24280018

Khaled, Shaban A; Burley, Jonathan C; Alexander, Morgan R; Roberts, Clive J

2014-01-30

159

Floating emitter solar cell  

NASA Technical Reports Server (NTRS)

A front surface contact floating emitter solar cell transistor is provided in a semiconductor body (n-type), in which floating emitter sections (p-type) are diffused or implanted in the front surface. Between the emitter sections, a further section is diffused or implanted in the front surface, but isolated from the floating emitter sections, for use either as a base contact to the n-type semiconductor body, in which case the section is doped n+, or as a collector for the adjacent emitter sections.

Chih, Sah (inventor); Cheng, Li-Jen (inventor)

1987-01-01

160

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.

161

Micromechanisms with floating pivot  

SciTech Connect

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.

Garcia, Ernest J. (Albuquerque, NM)

2001-03-06

162

The Floating Reference Librarian  

ERIC Educational Resources Information Center

The floating librarian'' is one who interprets and adjusts the formal library structure to meet legitimate needs. This is one of the ways the academic reference librarian can gain greater acceptance with students and faculty. (9 references) (Author/NH)

Hernon, Peter; Pastine, Maureen

1972-01-01

163

Concrete production floating platforms  

SciTech Connect

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.

Letourneur, O.; Falcimaigne, J.

1981-01-01

164

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.

165

Fabrication and Evaluation of Bi-layer Tablet Containing Conventional Paracetamol and Modified Release Diclofenac Sodium  

PubMed Central

The objectives of present investigation were to achieve immediate release of paracetamol and tailored release of diclofenac sodium from bi-layer tablets. A 23 full factorial design was adopted using the amount of polyethylene glycol, microcrystalline cellulose and crospovidone as independent variables for fabricating paracetamol tablets. Diclofenac sodium tablets were prepared using hydroxypropyl methylcellulose as a matrixing agent. The results of analysis of variance showed that the friability of paracetamol was distinctly influenced by the formulation variables. The in vitro drug release behaviour of diclofenac tablets was compared with a marketed formulation. The optimized formulations of paracetamol and diclofenac sodium were used for manufacturing of bi-layer tablets. The bi-layer tablets showed immediate release of paracetamol and modified release of diclofenac. PMID:20838522

Gohel, M. C.; Parikh, R. K.; Nagori, S. A.; Jethwa, B. A.

2010-01-01

166

[Tablets and tablet production - with special reference to Icelandic conditions].  

PubMed

Modern tablet compression was instituted in England in 1844 by William Brockedon (1787-1854). The first tablets made according to Brockedon´s procedures contained watersoluble salts and were most likely compressed without expedients. In USA a watershed occurred around 1887 when starch (amylum maydis) was introduced to disperse tablets in aqueous milieu in order to corroborate bioavailability of drugs in the almentary canal. About the same time great advances in tablet production were introduced by the British firm Burroughs Wellcome and Co. In Denmark on the other hand tablet production remained on low scale until after 1920. As Icelandic pharmacies and drug firms modelled themselves mostly upon Danish firms tablet production was first instituted in Iceland around 1930. The first tablet machines in Iceland were hand-driven. More efficent machines came after 1945. Around 1960 three sizeable tablet producers were in Iceland; now there is only one. Numbers of individual tablet species (generic and proprietary) on the market rose from less than 10 in 1913 to 500 in 1965, with wide variations in numbers in between. Tablets have not wiped out other medicinal forms for peroral use but most new peroral drugs have been marketed in the form of tablets during the last decades. PMID:23695970

Skaftason, Jóhannes F; Jóhannesson, Thorkell

2013-04-01

167

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

PubMed Central

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

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

2013-01-01

168

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

PubMed

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

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

2014-09-01

169

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.

170

Development and In Vivo Floating Behavior of Verapamil HCl Intragastric Floating Tablets  

Microsoft Academic Search

A novel gastro retentive controlled release drug delivery system of verapamil HCl was formulated in an effort to increase\\u000a the gastric retention time of the dosage form and to control drug release. Hydroxypropylmethylcellulose (HPMC), carbopol,\\u000a and xanthan gum were incorporated for gel-forming properties. Buoyancy was achieved by adding an effervescent mixture of sodium\\u000a bicarbonate and anhydrous citric acid. In vitro

Anand Patel; Moin Modasiya; Dushyant Shah; Vishnu Patel

2009-01-01

171

CES 2011: Tablet Crazy  

ERIC Educational Resources Information Center

Ereaders are so last year. Tablets were the watchword at this year's annual Consumer Electronics Show (CES) in Las Vegas, January 6-9. This year, the show set new records, with some 2700 companies from around the world exhibiting at the multiple exhibition halls and 30,000 attendees gawking at the products. What did they see? There were still some…

Rapp, David

2011-01-01

172

What Floats Your Boat?  

NSDL National Science Digital Library

Students use modeling clay, a material that is denser than water and thus ordinarily sinks in water, to discover the principle of buoyancy. They begin by designing and building boats out of clay that will float in water, and then refine their designs so that their boats will carry as great a load (metal washers) as possible. Building a clay boat to hold as much weight as possible is an engineering design problem. Next, they compare amount of water displaced by a lump of clay that sinks to the amount of water displaced by the same lump of clay when it is shaped so as to float. Determining the masses of the displaced water allows them to arrive at Archimedes' principle, whereby the mass of the displaced water equals the mass of the floating clay boat.

2014-09-18

173

Floating platform with monolithically formed float members and platform  

Microsoft Academic Search

Floating platforms for various offshore facilities are formed of float members monolithically connected to a superposed platform. The float members are spherically shaped and are formed of reinforced or prestressed concrete. The platform can be a hollow planar member or it can be curved in one or two directions, and the platforms are formed of prestressed concrete. Cylindrical shafts can

Finsterwalder

1981-01-01

174

Gauge well float for floating root storage tanks  

Microsoft Academic Search

A gauge well float includes a sealed cylinder having rounded ends. A tube is disposed along the vertical axis of the cylinder and held in place by the rounded ends. A weighted cable suspended within the gauge well passes through the tube and keeps the float centered within the gauge well. It also provides a means for removing the float

J. A. Sayles; W. J. Norwood

1984-01-01

175

Modifying drug release and tablet properties of starch acetate tablets by dry powder agglomeration.  

PubMed

In this study three model drugs (N-acetyl-D-glucosamine (NAG), anhydrous caffeine, and propranolol hydrochloride) were agglomerated with starch acetate (SA) by mixing the binary powders on a stainless steel (SS) plate. Agglomeration was induced by triboelectrification of the particles during mixing, and it was evaluated as a method to achieve controlled drug release rate. These agglomerates, mixed with different amounts of a disintegrant, were compressed into tablets whose dissolution characteristics were determined. Triboelectric measurements showed that when the drugs were in contact with SS, charges of the opposite polarity were generated to SA (+) and caffeine and NAG (-) promoting adhesion. Instead, propranolol HCl was charged with the same polarity as SA. SEM micrographs showed that smaller caffeine particles, in spite of their larger negative charge, agglomerated less efficiently with SA than larger NAG particles. This emphasizes the importance of particle size in the agglomeration process. Propranolol HCl did not form agglomerates with SA since their particle sizes and charges were identical. As a result, agglomeration of powders prior to tablet compression allows for modification and control of the release rate of the drugs from the SA matrix tablets as well as the tensile strength of the tablets. PMID:17075868

Mäki, Riikka; Suihko, Eero; Rost, Susanne; Heiskanen, Minna; Murtomaa, Matti; Lehto, Vesa-Pekka; Ketolainen, Jarkko

2007-02-01

176

Floating Versus Sinking  

NASA Astrophysics Data System (ADS)

Small objects that are more dense than water may still float at the air-water interface because of surface tension. Whether this is possible depends not only on the density and size of the object, but also on its shape and surface properties, whether other objects are nearby, and how gently the object is placed at the interface. This review surveys recent work to quantify when objects can float and when they must sink. Much interest in this area has been driven by studies of the adaptations of water-walking insects to life at interfaces. I therefore discuss these results in the context of this and other applications.

Vella, Dominic

2015-01-01

177

Gastroretentive Pulsatile Release Tablets of Lercanidipine HCl: Development, Statistical Optimization, and In Vitro and In Vivo Evaluation  

PubMed Central

The present study was aimed at the development of gastroretentive floating pulsatile release tablets (FPRTs) of lercanidipine HCl to enhance the bioavailability and treat early morning surge in blood pressure. Immediate release core tablets containing lercanidipine HCl were prepared and optimized core tablets were compression-coated using buoyant layer containing polyethylene oxide (PEO) WSR coagulant, sodium bicarbonate, and directly compressible lactose. FPRTs were evaluated for various in vitro physicochemical parameters, drug-excipient compatibility, buoyancy, swelling, and release studies. The optimized FPRTs were tested in vivo in New Zealand white rabbits for buoyancy and pharmacokinetics. DoE optimization of data revealed FPRTs containing PEO (20%?w/w) with coat weight 480?mg were promising systems exhibiting good floating behavior and lag time in drug release. Abdominal X-ray imaging of rabbits after oral administration of the tablets, confirmed the floating behavior and lag time. A quadratic model was suggested for release at 7th and 12th?h and a linear model was suggested for release lag time. The FPRT formulation improved pharmacokinetic parameters compared to immediate release tablet formulation in terms of extent of absorption in rabbits. As the formulation showed delay in drug release both in vitro and in vivo, nighttime administration could be beneficial to reduce the cardiovascular complications due to early morning surge in blood pressure. PMID:25525619

Reddy, Gagganapalli Santhoshi; Nayak, Usha Yogendra; Deshpande, Praful Balavant; Mutalik, Srinivas

2014-01-01

178

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

PubMed

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

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

2013-01-01

179

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

PubMed Central

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.

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

2013-01-01

180

21 CFR 520.312 - Carnidazole tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Carnidazole tablets. 520.312 Section 520.312 Food and...NEW ANIMAL DRUGS § 520.312 Carnidazole tablets. (a) Specifications. Each tablet contains 10 milligrams of carnidazole....

2014-04-01

181

21 CFR 520.1380 - Methocarbamol tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 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...

2013-04-01

182

21 CFR 520.1900 - Primidone tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 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...

2014-04-01

183

21 CFR 520.455 - Clomipramine tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 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...

2013-04-01

184

21 CFR 520.1451 - Moxidectin tablets.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Moxidectin tablets. 520.1451 Section 520.1451 Food and...NEW ANIMAL DRUGS § 520.1451 Moxidectin tablets. (a) Specifications . Each tablet contains 30, 68, or 136 micrograms of...

2011-04-01

185

21 CFR 520.928 - Firocoxib tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Firocoxib tablets. 520.928 Section 520.928 Food...NEW ANIMAL DRUGS § 520.928 Firocoxib tablets. (a) Specifications . Each chewable tablet contains 57 or 227 milligrams (mg)...

2012-04-01

186

21 CFR 520.1900 - Primidone tablets.  

Code of Federal Regulations, 2010 CFR

...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...

2010-04-01

187

21 CFR 520.928 - Firocoxib tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Firocoxib tablets. 520.928 Section 520.928 Food...NEW ANIMAL DRUGS § 520.928 Firocoxib tablets. (a) Specifications . Each chewable tablet contains 57 or 227 milligrams (mg)...

2013-04-01

188

21 CFR 520.581 - Dichlorophene tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Dichlorophene tablets. 520.581 Section 520.581 Food and...NEW ANIMAL DRUGS § 520.581 Dichlorophene tablets. (a) Specifications. Each tablet contains 1 gram of dichlorophene. (b)...

2012-04-01

189

21 CFR 520.1380 - Methocarbamol tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 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...

2014-04-01

190

21 CFR 520.2088 - Roxarsone tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 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...

2013-04-01

191

21 CFR 520.1900 - Primidone tablets.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

192

21 CFR 520.1451 - Moxidectin tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Moxidectin tablets. 520.1451 Section 520.1451 Food and...NEW ANIMAL DRUGS § 520.1451 Moxidectin tablets. (a) Specifications . Each tablet contains 30, 68, or 136 micrograms of...

2013-04-01

193

21 CFR 520.1380 - Methocarbamol tablets.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

194

21 CFR 520.1870 - Praziquantel tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Praziquantel tablets. 520.1870 Section 520.1870 Food and...NEW ANIMAL DRUGS § 520.1870 Praziquantel tablets. (a) Specifications . Each tablet contains: (1) 34 milligrams (mg)...

2012-04-01

195

21 CFR 520.312 - Carnidazole tablets.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Carnidazole tablets. 520.312 Section 520.312 Food and...NEW ANIMAL DRUGS § 520.312 Carnidazole tablets. (a) Specifications. Each tablet contains 10 milligrams of carnidazole....

2010-04-01

196

21 CFR 520.1451 - Moxidectin tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Moxidectin tablets. 520.1451 Section 520.1451 Food and...NEW ANIMAL DRUGS § 520.1451 Moxidectin tablets. (a) Specifications. Each tablet contains 30, 68, or 136 micrograms of...

2014-04-01

197

21 CFR 520.312 - Carnidazole tablets.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Carnidazole tablets. 520.312 Section 520.312 Food and...NEW ANIMAL DRUGS § 520.312 Carnidazole tablets. (a) Specifications. Each tablet contains 10 milligrams of carnidazole....

2011-04-01

198

21 CFR 520.1451 - Moxidectin tablets.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Moxidectin tablets. 520.1451 Section 520.1451 Food and...NEW ANIMAL DRUGS § 520.1451 Moxidectin tablets. (a) Specifications . Each tablet contains 30, 68, or 136 micrograms of...

2010-04-01

199

21 CFR 520.1870 - Praziquantel tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Praziquantel tablets. 520.1870 Section 520.1870 Food and...NEW ANIMAL DRUGS § 520.1870 Praziquantel tablets. (a) Specifications . Each tablet contains: (1) 34 milligrams (mg)...

2013-04-01

200

21 CFR 520.1870 - Praziquantel tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Praziquantel tablets. 520.1870 Section 520.1870 Food and...NEW ANIMAL DRUGS § 520.1870 Praziquantel tablets. (a) Specifications. Each tablet contains: (1) 34 milligrams (mg)...

2014-04-01

201

21 CFR 520.1900 - Primidone tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 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...

2013-04-01

202

21 CFR 520.1310 - Marbofloxacin tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Marbofloxacin tablets. 520.1310 Section 520.1310 Food and...ANIMAL DRUGS § 520.1310 Marbofloxacin tablets. (a) Specifications . Each tablet contains 25, 50, 100, or 200...

2012-04-01

203

21 CFR 520.1870 - Praziquantel tablets.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Praziquantel tablets. 520.1870 Section 520.1870 Food and...NEW ANIMAL DRUGS § 520.1870 Praziquantel tablets. (a) Specifications . Each tablet contains: (1) 34 milligrams (mg)...

2011-04-01

204

21 CFR 520.581 - Dichlorophene tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Dichlorophene tablets. 520.581 Section 520.581 Food and...NEW ANIMAL DRUGS § 520.581 Dichlorophene tablets. (a) Specifications. Each tablet contains 1 gram of dichlorophene. (b)...

2014-04-01

205

21 CFR 520.581 - Dichlorophene tablets.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Dichlorophene tablets. 520.581 Section 520.581 Food and...NEW ANIMAL DRUGS § 520.581 Dichlorophene tablets. (a) Specifications. Each tablet contains 1 gram of dichlorophene. (b)...

2011-04-01

206

21 CFR 520.1451 - Moxidectin tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Moxidectin tablets. 520.1451 Section 520.1451 Food and...NEW ANIMAL DRUGS § 520.1451 Moxidectin tablets. (a) Specifications . Each tablet contains 30, 68, or 136 micrograms of...

2012-04-01

207

21 CFR 520.312 - Carnidazole tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Carnidazole tablets. 520.312 Section 520.312 Food and...NEW ANIMAL DRUGS § 520.312 Carnidazole tablets. (a) Specifications. Each tablet contains 10 milligrams of carnidazole....

2012-04-01

208

21 CFR 520.455 - Clomipramine tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 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...

2014-04-01

209

21 CFR 520.928 - Firocoxib tablets.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Firocoxib tablets. 520.928 Section 520.928 Food...NEW ANIMAL DRUGS § 520.928 Firocoxib tablets. (a) Specifications . Each chewable tablet contains 57 or 227 milligrams (mg)...

2010-04-01

210

21 CFR 520.1310 - Marbofloxacin tablets.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Marbofloxacin tablets. 520.1310 Section 520.1310 Food and...ANIMAL DRUGS § 520.1310 Marbofloxacin tablets. (a) Specifications . Each tablet contains 25, 50, 100, or 200...

2010-04-01

211

21 CFR 520.1900 - Primidone tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 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...

2012-04-01

212

21 CFR 520.455 - Clomipramine tablets.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

213

21 CFR 520.581 - Dichlorophene tablets.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Dichlorophene tablets. 520.581 Section 520.581 Food and...NEW ANIMAL DRUGS § 520.581 Dichlorophene tablets. (a) Specifications. Each tablet contains 1 gram of dichlorophene. (b)...

2010-04-01

214

21 CFR 520.1310 - Marbofloxacin tablets.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Marbofloxacin tablets. 520.1310 Section 520.1310 Food and...ANIMAL DRUGS § 520.1310 Marbofloxacin tablets. (a) Specifications . Each tablet contains 25, 50, 100, or 200...

2011-04-01

215

21 CFR 520.928 - Firocoxib tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Firocoxib tablets. 520.928 Section 520.928 Food...NEW ANIMAL DRUGS § 520.928 Firocoxib tablets. (a) Specifications. Each chewable tablet contains 57 or 227 milligrams (mg)...

2014-04-01

216

21 CFR 520.312 - Carnidazole tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Carnidazole tablets. 520.312 Section 520.312 Food and...NEW ANIMAL DRUGS § 520.312 Carnidazole tablets. (a) Specifications. Each tablet contains 10 milligrams of carnidazole....

2013-04-01

217

21 CFR 520.1380 - Methocarbamol tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 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...

2012-04-01

218

21 CFR 520.455 - Clomipramine tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 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...

2012-04-01

219

21 CFR 520.928 - Firocoxib tablets.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Firocoxib tablets. 520.928 Section 520.928 Food...NEW ANIMAL DRUGS § 520.928 Firocoxib tablets. (a) Specifications . Each chewable tablet contains 57 or 227 milligrams (mg)...

2011-04-01

220

21 CFR 520.1310 - Marbofloxacin tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Marbofloxacin tablets. 520.1310 Section 520.1310 Food and...ANIMAL DRUGS § 520.1310 Marbofloxacin tablets. (a) Specifications. Each tablet contains 25, 50, 100, or 200...

2014-04-01

221

21 CFR 520.1870 - Praziquantel tablets.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Praziquantel tablets. 520.1870 Section 520.1870 Food and...NEW ANIMAL DRUGS § 520.1870 Praziquantel tablets. (a) Specifications . Each tablet contains: (1) 34 milligrams (mg)...

2010-04-01

222

21 CFR 520.581 - Dichlorophene tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Dichlorophene tablets. 520.581 Section 520.581 Food and...NEW ANIMAL DRUGS § 520.581 Dichlorophene tablets. (a) Specifications. Each tablet contains 1 gram of dichlorophene. (b)...

2013-04-01

223

Preparation and in vitro characterization of non-effervescent floating drug delivery system of poorly soluble drug, carvedilol phosphate.  

PubMed

The objective of the study was to enhance the solubility of carvedilol phosphate and to formulate it into non-effervescent floating tablets using swellable polymers. Solid dispersions (SD) of carvedilol were prepared with hydrophilic carriers such as polyvinylpyrrolidone and poloxamer to enhance solubility. Non-effervescent floating tablets were prepared with a combination of optimized solid dispersions and release retarding polymers/swellable polymers such as xanthan gum and polyethylene oxide. Tablets were evaluated for physicochemical properties such as hardness, thickness and buoyancy. SD prepared with the drug to poloxamer ratio of 1:4 by melt granulation showed a higher dissolution rate than all other dispersions. Formulations containing 40 mg of polyethylene oxide (C-P40) and 50 mg xanthan gum (C-X50) were found to be best, with the drug retardation up to 12 hours. Optimized formulations were characterized using FTIR and DSC and no drug and excipient interactions were detected. PMID:25531788

Srikanth Meka, Venkata; Wee Liang, Vanitha A P Hong; Dharmalingham, Senthil Rajan; Sheshala, Ravi; Gorajana, Adinarayana

2014-12-01

224

Compound floating pivot micromechanisms  

DOEpatents

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.

Garcia, Ernest J. (Albuquerque, NM)

2001-04-24

225

Corona from floating electrodes  

Microsoft Academic Search

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

Francisco Roman; Vernon Cooray; Viktor Scuka

1996-01-01

226

Floating Paper Clip  

NSDL National Science Digital Library

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.

WGBH Boston

2002-01-01

227

Root Beer Float  

NSDL National Science Digital Library

In this quick activity/demonstration about density, learners examine what happens when two cans of root beer--one diet and one regular--are placed in a large container of water. Do they sink or float? Use this activity to introduce learners to the importance of density as well as the nutritional content of soft drinks.

Colorado State University

2009-01-01

228

Float My Boat  

NSDL National Science Digital Library

In this activity, learners use tinfoil to build and test their own boats - which designs will float, and which will sink? Learners must adjust many variables in their boat design to maximize stability and flotation, in order for the boat to support a heavy load of pennies. This activity is great used with lessons on engineering or design.

2013-12-05

229

Floating Vegetation in Pantanal  

USGS Multimedia Gallery

Mass of floating vegetation (embalsado) on Rio Negro river along the border between Paraguay and Bolivia. Located near RAMSAR site and Rio Negro National Park in the Pantanal ecoregion. This region, situated in the extreme northeastern corner of western Paraguay and extending south along the Paragua...

230

Floating Vegetation in Pantanal  

USGS Multimedia Gallery

Mass of floating vegetation (embalsado)on Rio Negro river on the border between Paraguay and Bolivia. Located near RAMSAR site and Rio Negro National Park in the Pantanal ecoregion. This region, situated in the extreme northeastern corner of western Paraguay and extending south along the Paraguay ri...

231

Floating Head Cup  

NSDL National Science Digital Library

In this activity, learners watch a figure "magically" float up through the air. Learners use 2 straws, a cup, rubber band, pipe cleaner, and piece of buoyant material to make a simple model of novel Chinese art pieces, which are typically made out of ceramics. Use this activity to demonstrate the relationship between density and buoyancy.

Watsonville Environmental Science Workshop

2011-01-01

232

Development and evaluation of orally disintegrating tablets (ODTs) containing Ibuprofen granules prepared by hot melt extrusion.  

PubMed

In the current study Ibuprofen was embedded in a methacrylate copolymer (Eudragit® EPO) matrix to produce solid dispersions by hot-melt extrusion (HME) processing. The obtained granules were incorporated in orally disintegrating tablets (ODTs). The tablets were developed by varying the ratio of superdisintegrants such as sodium croscarmellose and crosslinked polyvinylpyrrolidone grades while a direct compression process was used to compress the ODTs under various compaction forces to optimize tablet robustness. The properties of the compressed tablets which included porosity, hardness, friability and dissolution profiles were further evaluated and compared with Nurofen® Meltlet ODTs. The taste and sensory evaluation in human volunteers demonstrated excellence in masking the bitter active and improved tablet palatability. PMID:21592751

Gryczke, Andreas; Schminke, Silke; Maniruzzaman, Mohammed; Beck, Julien; Douroumis, Dennis

2011-09-01

233

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

PubMed

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

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

2014-01-01

234

Tablet PCs: The Write Approach  

ERIC Educational Resources Information Center

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…

Milner, Jacob

2006-01-01

235

Hidden force floating ice  

E-print Network

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.

Chang Q. Sun

2015-01-17

236

Float or Sink?  

NSDL National Science Digital Library

In this water activity, learners test which objects float and which sink. Learners discover that objects behave differently in water. Learners are also introduced to the idea of "predicting" and record their predictions and observations on a chart. This activity is part of the curriculum Explore Water, related to Peep and the Big Wide World, a preschool science series on public television. The activity starts on page 41 of the PDF.

WGBH Educational Foundation

2005-01-01

237

Float valve control  

SciTech Connect

This patent describes a liquid level control device for monitoring the level of water in a steam generating tank between predetermined upper, intermediate and lower levels, the tank equipped with a valve for introducing water into the tank and valve means for introducing heat energy to the water to generate steam. The device consists of: (a) a glass gauge tube adapted to be vertically mounted exteriorally of the tank; (b) a top and bottom cover covering the ends of the glass gauge tube, the bottom cover including an opening for communicating with the liquid in the tank and the top cover including an opening for communicating with the steam generated in the tank; (c) upper and lower magnetic float means mounted co-axially within the glass guage tube; (d) the upper magnetic float means including means to activate the water valve when the water is in the region of the predetermined intermediate level so as to introduce water into the tank until the water is in the region of the predetermined upper level, and to deactivate the water valve and stop the introduction of water into the tank when the water is in the region of the predetermined upper level; (e) the lower magnetic float means is adapted to continuously maintain the application of heat energy during the introduction of water at the intermediate level, and the lower magnetic float means is adapted to activate the heat energy valve means to stop the application of heat energy in the steam generating tank when the water is in the region of the predetermined lower level.

Tchitdjian, J.K.

1986-08-12

238

Tablet PC and Computing Curriculum Initiative Evaluation of Tablet PC Supported Pedagogy  

E-print Network

Tablet PC and Computing Curriculum Initiative 2006 Evaluation of Tablet PC Supported Pedagogy http://www.cs.washington.edu/education/dl/presenter/ University of Washington Richard Anderson 2. Students write answers on slides on their tablets and send them to show on public display for discussion Classroom Interaction with Tablet PCs Classroom Presenter Tablet

Anderson, Richard

239

WindFloat: A floating foundation for offshore wind turbines  

Microsoft Academic Search

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

Dominique Roddier; Christian Cermelli; Alexia Aubault; Alla Weinstein

2010-01-01

240

Novel Floating General Element Simulators Using CBTA  

Microsoft Academic Search

In this study, a novel floating frequency depen- dent negative resistor (FDNR), floating inductor, floating ca- pacitor and floating resistor simulator circuit employing two CBTAs and three passive components is proposed. The pre- sented circuit can realize floating FDNR, inductor, capacitor or resistor depending on the passive component selection. Since the passive elements are all grounded, this circuit is suitable

Umut Engin AYTEN; Mehmet SAGBAS; Norbert HERENCSAR; Jaroslav KOTON

2012-01-01

241

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

PubMed

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

Ma, Lulu; Deng, Li; Chen, Jianming

2014-07-01

242

21 CFR 520.1199 - Ivermectin, pyrantel, and praziquantel tablets.  

Code of Federal Regulations, 2012 CFR

... Ivermectin, pyrantel, and praziquantel tablets. 520.1199 Section 520.1199 Food... Ivermectin, pyrantel, and praziquantel tablets. (a) Specifications . Each chewable tablet contains: (1) 34 micrograms...

2012-04-01

243

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

Code of Federal Regulations, 2013 CFR

...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...

2013-04-01

244

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

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

245

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

Code of Federal Regulations, 2014 CFR

...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...

2014-04-01

246

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

Code of Federal Regulations, 2012 CFR

...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...

2012-04-01

247

21 CFR 520.1199 - Ivermectin, pyrantel, and praziquantel tablets.  

Code of Federal Regulations, 2013 CFR

... Ivermectin, pyrantel, and praziquantel tablets. 520.1199 Section 520.1199 Food... Ivermectin, pyrantel, and praziquantel tablets. (a) Specifications . Each chewable tablet contains: (1) 34 micrograms...

2013-04-01

248

21 CFR 520.1199 - Ivermectin, pyrantel, and praziquantel tablets.  

Code of Federal Regulations, 2014 CFR

... Ivermectin, pyrantel, and praziquantel tablets. 520.1199 Section 520.1199 Food... Ivermectin, pyrantel, and praziquantel tablets. (a) Specifications. Each chewable tablet contains: (1) 34 micrograms...

2014-04-01

249

21 CFR 520.1199 - Ivermectin, pyrantel, and praziquantel tablets.  

Code of Federal Regulations, 2011 CFR

... Ivermectin, pyrantel, and praziquantel tablets. 520.1199 Section 520.1199 Food... Ivermectin, pyrantel, and praziquantel tablets. (a) Specifications . Each chewable tablet contains: (1) 34 micrograms...

2011-04-01

250

Bioadhesive Mini-Tablets for Vaginal Drug Delivery  

PubMed Central

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

Hiorth, Marianne; Nilsen, Susanne; Tho, Ingunn

2014-01-01

251

Formulation and evaluation of floating oral in situ gelling system of amoxicillin.  

PubMed

Purpose. Effective Helicobacter pylori eradication requires delivery of the antibiotic locally in the stomach. High dose of amoxicillin (750 to 1000?mg) is difficult to incorporate in floating tablets but can easily be given in liquid dosage form. Keeping the above facts in mind, we made an attempt to develop a new floating in situ gelling system of amoxicillin with increased residence time using sodium alginate as gelling polymer to eradicate H. pylori. Methods. Floating in situ gelling formulations were prepared using sodium alginate, calcium chloride, sodium citrate, hydroxypropyl methyl cellulose K100, and sodium bicarbonate. The prepared formulations were evaluated for solution viscosity, floating lag time, total floating time, and in vitro drug release. The formulation was optimized using a 3(2) full factorial design. Dissolution data were fitted to various models to ascertain kinetic of drug release. Regression analysis and analysis of variance were performed for dependent variables. Results. All formulations (F(1)-F(9)) showed floating within 30?s and had total floating time of more than 24?h. All the formulations showed good pourability. It was observed that concentration of sodium alginate and HPMC K100 had significant influence on floating lag time, cumulative percentage drug release in 6?h and 10?h. The batch F(8) was considered optimum since it showed more similarity in drug release (f(2) = 74.38) to the theoretical release profile. Conclusion. Floating in situ gelling system of amoxicillin can be formulated using sodium alginate as a gelling polymer to sustain the drug release for 10 to 12?h with zero-order release kinetics. PMID:22389849

Patel, Dasharath M; Patel, Divyesh K; Patel, Chhagan N

2011-01-01

252

Application of design of experiment for floating drug delivery of tapentadol hydrochloride.  

PubMed

The aim of the present study was to apply design of experiment (DOE) to optimize floating drug delivery of tapentadol hydrochloride. Tapentadol hydrochloride is a synthetic opioid used as a centrally acting analgesic and effective in both experimental and clinical pain. The half-life of the drug is about 4 hours and oral dose is 50 to 250?mg twice a day. For optimization 3(2) full factorial design was employed for formulation of tapentadol hydrochloride tablets. Sodium bicarbonate was incorporated as a gas-generating agent. Combination of polymers Xanthan gum and Locust bean gum was used to achieve controlled release effect. The concentration of polymers was considered as the independent variables and dependent variables were floating lag time and swelling index of the tablets. From the factorial batches, it was observed that formulation containing combination of 20% sodium bicarbonate and 10% citric acid shows optimum floating ability whereas the formulation containing 20% Xanthan gum and 28% Locust bean gum shows optimum sustained drug release pattern with adequate floating. PMID:23878616

Jagdale, Swati C; Patil, Somnath; Kuchekar, Bhanudas S

2013-01-01

253

Floating JMaRT  

E-print Network

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.

Guillaume Bossard; Stefanos Katmadas

2014-12-16

254

Floating JMaRT  

E-print Network

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.

Bossard, Guillaume

2014-01-01

255

Will It Float?  

NSDL National Science Digital Library

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.

Jeff Major

2006-01-01

256

LOW POWER PROBABILISTIC FLOATING POINT MULTIPLIER  

E-print Network

LOW POWER PROBABILISTIC FLOATING POINT MULTIPLIER DESIGN Aman Gupta,,*, Satyam Mandavalli, Vincent Power Probabilistic Design Probabilistic Floating Point Multiplier Low Power Techniques C simulator Floating Point Multiplier Low Power Techniques C simulator · Ray Tracing Application · Simulations

Mooney, Vincent

257

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 ...

258

Well pipe float valve  

SciTech Connect

This patent describes a drill pipe float assembly comprising an elongated cylindrical cage having upper and lower rings joined by diametrically opposite vertical wall members. The upper ring has a downwardly facing valve seat on its inner perimeter. The assembly includes a valve stem guide member supported by the lower ring including a central vertical bearing sleeve slidable guiding the depending end portion of a valve stem. The valve stem has a valve on its upper end including an elastomer seal seating and unseating on the valve seat in response to the direction of fluid flow through the ring members, cylindrical spring retainer on the valve stem in contact with the valve seal, and a helical spring surrounding the valve stem and biasing the valve toward its seat, the improvement comprising: means secured to the respective confronting end surfaces of the spring retainer and the valve stem guide sleeve for interdigitated engagement in response to fluid flow in one direction through the float assembly.

Taylor, J.S.

1986-11-18

259

Does It Sink or Float?  

ERIC Educational Resources Information Center

This activity is designed to teach prekindergarten to second grade students about the concept of sink or float through an inquiry activity. Students will use familiar objects to predict and test the properties of sink and float. Background information is offered to teachers to assist them with this activity. This lesson begins with an engaging…

McDonald, Judith Richards

2012-01-01

260

Tablet Splitting: A Risky Practice  

MedlinePLUS

... the medicine slowly. Splitting these tablets destroys the coating, which means you might absorb the medicine too ... Continuing Education Inspections/Compliance State & Local Officials Consumers Industry Health Professionals FDA Archive Links on this page:

261

21 CFR 520.82a - Aminopropazine fumarate tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 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...

2012-04-01

262

21 CFR 520.1284 - Sodium liothyronine tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 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...

2014-04-01

263

21 CFR 520.82a - Aminopropazine fumarate tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 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...

2013-04-01

264

21 CFR 520.1284 - Sodium liothyronine tablets.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

265

21 CFR 520.1284 - Sodium liothyronine tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 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...

2013-04-01

266

21 CFR 520.82a - Aminopropazine fumarate tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 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...

2014-04-01

267

21 CFR 520.82a - Aminopropazine fumarate tablets.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

268

21 CFR 520.1284 - Sodium liothyronine tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 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...

2012-04-01

269

Very Large Floating Structures: Applications, Research and Development  

Microsoft Academic Search

Very large floating structures (VLFS) have attracted the attention of architects, city planners, and engineers because they provide an exciting and environmentally friendly solution for land creation from the sea as opposed to the traditional land reclamation method. The applications of VLFS as floating piers, floating hotels, floating fuel storage facilities, floating stadia, floating bridges, floating airports, and even floating

C. M. Wang; Z. Y. Tay

2011-01-01

270

Floating Silicon Method  

SciTech Connect

The Floating Silicon Method (FSM) project at Applied Materials (formerly Varian Semiconductor Equipment Associates), has been funded, in part, by the DOE under a “Photovoltaic Supply Chain and Cross Cutting Technologies” grant (number DE-EE0000595) for the past four years. The original intent of the project was to develop the FSM process from concept to a commercially viable tool. This new manufacturing equipment would support the photovoltaic industry in following ways: eliminate kerf losses and the consumable costs associated with wafer sawing, allow optimal photovoltaic efficiency by producing high-quality silicon sheets, reduce the cost of assembling photovoltaic modules by creating large-area silicon cells which are free of micro-cracks, and would be a drop-in replacement in existing high efficiency cell production process thereby allowing rapid fan-out into the industry.

Kellerman, Peter

2013-12-21

271

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

PubMed

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

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

2014-03-01

272

Floating into Deep Space  

NASA Astrophysics Data System (ADS)

Is it possible for spaceflight to become more sustainable? Artist and architect Tomas Saraceno proposes a long-term artscience research project based on his initial work with solar balloons to join with the efforts of engineers such as John Powell, working on the Airship to Orbit experiments, which describe a three stage process of using airships to fly to a large suborbital "Dark Sky Station' then literally floating into orbit with additional electrical and chemical propulsion. (See: http://www.jpaerospace.com) In his artworks Tomás Saraceno proposes cell-like flying cities as possible architectonic living spaces in direct reference to Buckminster Fuller's Cloud Nine (circa 1960). The fantastic architectural utopia Cloud Nine consists of a freely floating sphere measuring one mile in diameter that offers living space to several autonomous communities encompassing thousands of inhabitants each. The notion of the cloud is essential to the artist's work. The cloud as metaphor stands for artistic intention, for the meaning of territory and border in today's (urban) society, and for exploring possibilities for the sustainable development of the human living environment. In Saraceno's work this environment is not limited to the earth, but is explicitly conceived to reach into outer space. (Biomimetic Constructions- On the works of Tomás Saraceno By Katharina Schlüter) Saraceno is also interested in human factors experiments using his existing constructions as analogue environments for living on Mars and is proposing carry out a series of workshops, experiments and solar balloon launces in White Sands desert in early 2016 in collaboration with the curator Dr Rob La Frenais, the Rubin Center at The University of Texas at El Paso and various scientific partners.

La Frenais, R.; Saraceno, T.; Powell, J.

2014-04-01

273

2557 (1 2556) 1 1182 ACARBOSE 50 MG COMPRESSED TAB. FOIL ACARBOSE TABLET TABLET 3.32  

E-print Network

TABLET TABLET 3.32 2 735 ACETAR 1000 ML ACETATED RINGERS INJECTION 1000 ML 44.00 3 2338 ACETAZOLAMIDE 250 MG COMPRESSED TAB. ACETAZOLAMIDE TABLET TABLET 1.75 4 1553 ACETYLCYSTEINE 100 MG GRANULE VIAL 214.00 12 962 ACYCLOVIR 200 MG COMPRESSED TAB. FOIL ACYCLOVIR TABLET TABLET 1.80 13 108 ACYCLOVIR

Laksanacharoen, Sathaporn

274

DEM simulation of continuous tablet coating: Effects of tablet shape and fill level on inter-tablet coating variability  

Microsoft Academic Search

Tablet coating is a common pharmaceutical technique of applying a thin polymer-based film to a tablet or a granule containing active pharmaceutical ingredients (APIs). Inter- and intra-tablet variability of film coating is a critical issue in the production of solid oral dosage forms. In fact, inhomogeneity in the coating thickness can lead to significant variations in the delivery rate of

Daniele Suzzi; Gregor Toschkoff; Stefan Radl; Daniel Machold; Simon D. Fraser; Benjamin J. Glasser; Johannes G. Khinast

275

E-Books and the Tablet PC.  

ERIC Educational Resources Information Center

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)

Goodwin-Jones, Bob

2003-01-01

276

Profiling floating point value ranges for reconfigurable  

E-print Network

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

Kelly, Paul H. J.

277

Interval Computations Rounding of Floating Point Intervals  

E-print Network

Interval Computations No 4, 1994 Rounding of Floating Point Intervals Marc Daumas and David W. Matula Correct rounding of the infinitely precise arithmetic as prescribed for the float- ing point #12;Rounding of Floating Point Intervals 29 1 Introduction The IEEE floating point standard has been

Kearfott, R. Baker

278

A floating multiparticulate system for ofloxacin based on a multilayer structure: In vitro and in vivo evaluation.  

PubMed

The purpose of this research was to develop a novel gastroretentive multiparticulate system with floating ability. This system was designed to provide drug-loaded pellets coated with three successive coatings-the retarding film (ethyl cellulose), the effervescent layer (sodium bicarbonate) and the gas-entrapped polymeric membrane (Eudragit RL 30D). The floating pellets were evaluated for SEM, floating characteristic parameters, in vitro release and bioavailability in New Zealand rabbits. The zero-order release theory model is designed to interpret the release processes. Due to the swelling property, high flexibility and high water permeability, Eudragit RL 30D was used as a gas-entrapped polymeric membrane. The obtained pellets exhibit excellent floating ability and release characteristics. Analysis of the release mechanism showed a zero-order release for the first 8h because of the osmotic pressure of the saturated solution inside of the membrane, which was in accordance with that predicted. Abdominal X-ray images showed that the gastroretention period of the floating barium sulfate-labeled pellets was no less than 6h. The relative bioavailability of the floating pellets compared with reference tablets was 113.06 ± 23.83%. All these results showed that the floating pellets are a feasible approach for the gastroretentive drug delivery system. PMID:22525085

Zhang, Chungang; Xu, Ming; Tao, Xiaoguang; Tang, Jingya; Liu, Zitong; Zhang, Yu; Lin, Xia; He, Haibing; Tang, Xing

2012-07-01

279

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

E-print Network

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

California at Davis, University of

280

L11 Floating Point 1Comp 411 Floating-Point Arithmetic  

E-print Network

L11 ­ Floating Point 1Comp 411 Floating-Point Arithmetic if ((A + A) - A == A) { SelfDestruct() } #12;L11 ­ Floating Point 2Comp 411 What is the problem? Many numeric applications require numbers over *COULD* use bigger integers Floating point is a better answer for most applications. #12;L11 ­ Floating

Bishop, Gary

281

Unleashed: Web tablet integration into the home  

Microsoft Academic Search

To understand how web access from a portable tablet appliance changes the way people use the Internet, MediaOne gave families pen-based tablet computers with a wireless connection to our high-speed data network. We used ethnographic and usability methods to understand how tablets would be integrated into household activities and to define user requirements for such devices. Participants viewed the tablet

Anne P. McClard; Patricia Somers

2000-01-01

282

Galileo's Telescopy and Jupiter's Tablet  

NASA Astrophysics Data System (ADS)

A previous paper (BAAS 33:4, 1363, 2001) reported on the dramatic scene in Shakespeare's Cymbeline that features the descent of the deity Jupiter. The paper suggested that the four ghosts circling the sleeping Posthumus denote the four Galilean moons of Jupiter. The god Jupiter commands the ghosts to lay a tablet upon the prone Posthumus, but says that its value should not be overestimated. When Posthumus wakens he notices the tablet, which he calls a "book." Not only has the deity's "tablet" become the earthling's "book," but it appears that the book has covers which Posthumus evidently recognizes because without even opening the book he ascribes two further properties to it: rarity, and the very property that Jupiter had earlier attributed, viz. that one must not read too much into it. The mystery deepens when the Jovian gift undergoes a second metamorphosis, to "label." With the help of the OED, the potentially disparate terms "tablet," "book," and "label," may be explained by terms appropriate either to supernatural or worldly beings. "Tablet" may recognize the Mosaic artifact, whereas "book" and "label" are probably mundane references to Galileo's Sidereus Nuncius which appeared shortly before Cymbeline. The message of the Olympian god indicates therefore that the book is unique even as its contents have limited value. The first property celebrates the fact that Galileo's book is the first of its kind, and the second advises that all results except the discovery of Jupiter's moons have been reported earlier, in Hamlet.

Usher, P. D.

2003-12-01

283

NULL Convention Floating Point Multiplier  

PubMed Central

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

Ramachandran, Seshasayanan

2015-01-01

284

Floating orbital molecular dynamics simulations.  

PubMed

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

Perlt, Eva; Brüssel, Marc; Kirchner, Barbara

2014-04-21

285

Control development for floating wind  

NASA Astrophysics Data System (ADS)

Control of a floating wind turbine has proven to be challenging, but essential for lowering the cost of floating wind energy. Topic of a recent joint R&D project by GustoMSC, MARIN and ECN, is the concept design and verification with coupled simulations and model tests of the GustoMSC Tri-Floater. Only using an integral design approach, including mooring and control design, a cost effective system can be obtained. In this project, ECN developed a general floating wind turbine control strategy and applied this in a case study to the GustoMSC Tri-Floater and the OC3Hywind spar, both equipped with the NREL 5MW RWT. The designed controller ensures stable operation, while maintaining proper speed and power regulation. The motions of the floating support are reduced and substantial load reduction has been achieved.

Savenije, Feike; Peeringa, Johan

2014-06-01

286

Organic molecular floating gate memories  

E-print Network

Flash memory devices dominate the non-volatile memory market, with device structures that utilize charge storage in polysilicon floating gates imbedded in insulating silicon oxide films'. As demands for high storage density, ...

Paydavosi, Sarah

2011-01-01

287

21 CFR 520.531 - Cythioate tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 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 §...

2014-04-01

288

21 CFR 520.1510 - Nitenpyram tablets.  

Code of Federal Regulations, 2011 CFR

...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)...

2011-04-01

289

Touch Screen Tablets and Emergent Literacy  

ERIC Educational Resources Information Center

The use of touch screen tablets by young children is increasing in the home and in early childhood settings. The simple tactile interface and finger-based operating features of tablets may facilitate preschoolers' use of tablet application software and support their educational development in domains such as literacy. This article reviews…

Neumann, Michelle M.; Neumann, David L.

2014-01-01

290

21 CFR 520.816 - Epsiprantel tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Epsiprantel tablets. 520.816 Section 520.816 Food and...NEW ANIMAL DRUGS § 520.816 Epsiprantel tablets. (a) Specifications . Each tablet contains either 12.5, 25, 50, or 100...

2013-04-01

291

21 CFR 520.816 - Epsiprantel tablets.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Epsiprantel tablets. 520.816 Section 520.816 Food and...NEW ANIMAL DRUGS § 520.816 Epsiprantel tablets. (a) Specifications . Each tablet contains either 12.5, 25, 50, or 100...

2010-04-01

292

21 CFR 520.531 - Cythioate tablets.  

Code of Federal Regulations, 2010 CFR

...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 §...

2010-04-01

293

21 CFR 520.531 - Cythioate tablets.  

Code of Federal Regulations, 2011 CFR

...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 §...

2011-04-01

294

21 CFR 520.1510 - Nitenpyram tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 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)...

2012-04-01

295

21 CFR 520.816 - Epsiprantel tablets.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Epsiprantel tablets. 520.816 Section 520.816 Food and...NEW ANIMAL DRUGS § 520.816 Epsiprantel tablets. (a) Specifications . Each tablet contains either 12.5, 25, 50, or 100...

2011-04-01

296

Tablet PC Enhanced Curricula University of Washington  

E-print Network

Tablet PC Enhanced Curricula University of Washington Richard Anderson http://www.cs.washington.edu/education/dl/presenter/ 2. Students write answers on slides on their tablets and send them back to the instructor Classroom · Tablet PC based classroom interaction system · Supports inking on slides to integrate slide based content

Anderson, Richard

297

21 CFR 520.531 - Cythioate tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 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 §...

2013-04-01

298

21 CFR 520.1510 - Nitenpyram tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 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)...

2014-04-01

299

21 CFR 520.1510 - Nitenpyram tablets.  

Code of Federal Regulations, 2010 CFR

...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)...

2010-04-01

300

21 CFR 520.812 - Enrofloxacin tablets.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

301

21 CFR 520.812 - Enrofloxacin tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 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...

2012-04-01

302

Mathematics Instruction and the Tablet PC  

ERIC Educational Resources Information Center

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…

Fister, K. Renee; McCarthy, Maeve L.

2008-01-01

303

21 CFR 520.816 - Epsiprantel tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Epsiprantel tablets. 520.816 Section 520.816 Food and...NEW ANIMAL DRUGS § 520.816 Epsiprantel tablets. (a) Specifications . Each tablet contains either 12.5, 25, 50, or 100...

2012-04-01

304

21 CFR 520.1510 - Nitenpyram tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 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)...

2013-04-01

305

21 CFR 520.812 - Enrofloxacin tablets.  

Code of Federal Regulations, 2010 CFR

...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...

2010-04-01

306

Scaffolding Equals Success in Teaching Tablet PCs  

ERIC Educational Resources Information Center

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…

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

2009-01-01

307

21 CFR 520.812 - Enrofloxacin tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 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...

2013-04-01

308

21 CFR 520.816 - Epsiprantel tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Epsiprantel tablets. 520.816 Section 520.816 Food and...NEW ANIMAL DRUGS § 520.816 Epsiprantel tablets. (a) Specifications. Each tablet contains either 12.5, 25, 50, or 100...

2014-04-01

309

21 CFR 520.1616 - Orbifloxacin tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 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...

2014-04-01

310

21 CFR 520.531 - Cythioate tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 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 §...

2012-04-01

311

21 CFR 520.1616 - Orbifloxacin tablets.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

312

Fast Dissolving Tablets of Aloe Vera Gel  

Microsoft Academic Search

Purpose : The objective of this work was to prepare and evaluate fast dissolving tablets of the nutraceutical, freeze dried Aloe vera gel. Methods: Fast dissolving tablets of the nutraceutical, freeze-dried Aloe vera gel, were prepared by dry granulation method. The tablets were evaluated for crushing strength, disintegration time, wetting time, friability, drug content and drug release. A 3 2

Jyotsana Madan; AK Sharma; Ramnik Singh

313

Tablet - next generation sequence assembly visualization  

Microsoft Academic Search

Summary: Tablet is a lightweight, high-performance graphical viewer for next generation sequence assemblies and alignments. Supporting a range of input assembly formats, Tablet provides high- quality visualizations showing data in packed or stacked views, al- lowing instant access and navigation to any region of interest, and whole contig overviews and data summaries. Tablet is both multi- core aware and memory-efficient,

Iain Milne; Micha Bayer; Linda Cardle; Paul Shaw; Gordon Stephen; Frank Wright; David Marshall

2010-01-01

314

Electrically floating, near vertical incidence, skywave antenna  

DOEpatents

An Electrically Floating, Near Vertical Incidence, Skywave (NVIS) Antenna comprising an antenna element, a floating ground element, and a grounding element. At least part of said floating ground element is positioned between said antenna element and said grounding element. The antenna is separated from the floating ground element and the grounding element by one or more electrical insulators. The floating ground element is separated from said antenna and said grounding element by one or more electrical insulators.

Anderson, Allen A.; Kaser, Timothy G.; Tremblay, Paul A.; Mays, Belva L.

2014-07-08

315

Use of supercritical fluid extraction for sample preparation of sustained-release felodipine tablets.  

PubMed

Supercritical fluid extraction (SFE) was shown to be an accurate and precise alternative to liquid extraction for sample preparation of sustained-release felodipine tablets (5 mg potency) while realizing an 80% reduction in solvent consumption. Extractions of felodipine spiked on an inert support were used to evaluate the solubility of felodipine in CO2 as well as analyte trapping after SFE. Even though the pure drug was found to be soluble in pure CO2, extractions of felodipine from the tablet matrix required moderate modifier concentrations [8.7% (v/v) methanol in CO2] in order to overcome strong matrix-drug interactions. Sequential static/dynamic extraction steps were also required to quantitatively recover the drug from the tablet matrix, indicating that the drug extraction was diffusion-limited. Average recoveries (n = 5) for the optimized SFE method were determined to be 4.93 mg felodipine tablet (98.6% claim) with an RSD of 1.2% versus those for the liquid extraction procedure (n = 5, 4.98 mg/tablet, 99.6% claim, 2.4% RSD). Similar levels of drug degradation (0.12% expressed as felodipine) were also obtained with both the traditional liquid extraction and with the SFE method. PMID:7891270

Howard, A L; Shah, M C; Ip, D P; Brooks, M A; Strode, J T; Taylor, L T

1994-11-01

316

Tests find hammering, fluid cutting, erosion cause float shoe failures  

Microsoft Academic Search

The results of a systematic test program to evaluate float equipment performance are presented. The testing has destroyed, over an eightmonth period, 160 float valves, float shoes and float collars. A new float valve design with greater resistance to failure has been developed as a result of the testing. New float collars and float shoes are expected to provide the

Stringfellow

1985-01-01

317

Floating wind turbine system  

NASA Technical Reports Server (NTRS)

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.

Viterna, Larry A. (Inventor)

2009-01-01

318

Skylab floating ice experiment  

NASA Technical Reports Server (NTRS)

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.

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

1975-01-01

319

Design and evaluation of hydrophobic coated buoyant core as floating drug delivery system for sustained release of cisapride  

PubMed Central

An inert hydrophobic buoyant coated–core was developed as floating drug delivery system (FDDS) for sustained release of cisapride using direct compression technology. Core contained low density, porous ethyl cellulose, which was coated with an impermeable, insoluble hydrophobic coating polymer such as rosin. It was further seal coated with low viscosity hydroxypropyl methyl cellulose (HPMC E15) to minimize moisture permeation and better adhesion with an outer drug layer. It was found that stable buoyant core was sufficient to float the tablet more than 8 h without the aid of sodium bicarbonate and citric acid. Sustained release of cisapride was achieved with HPMC K4M in the outer drug layer. The floating lag time required for these novel FDDS was found to be zero, however it is likely that the porosity or density of the core is critical for floatability of these tablets. The in vitro release pattern of these tablets in simulated gastric fluid showed the constant and controlled release for prolonged time. It can be concluded that the hydrophobic coated buoyant core could be used as FDDS for gastroretentive delivery system of cisapride or other suitable drugs. PMID:24825997

Jacob, Shery; Nair, Anroop B; Patil, Pandurang N

2010-01-01

320

Optimization studies on compression coated floating-pulsatile drug delivery of bisoprolol.  

PubMed

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

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

2013-01-01

321

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

PubMed Central

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

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

2013-01-01

322

Fresh look at floating shock fitting  

NASA Technical Reports Server (NTRS)

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.

Hartwich, PETER-M.

1990-01-01

323

Galileo's Telescopy and Jupiter's Tablet  

Microsoft Academic Search

A previous paper (BAAS 33:4, 1363, 2001) reported on the dramatic scene in Shakespeare's Cymbeline that features the descent of the deity Jupiter. The paper suggested that the four ghosts circling the sleeping Posthumus denote the four Galilean moons of Jupiter. The god Jupiter commands the ghosts to lay a tablet upon the prone Posthumus, but says that its value

P. D. Usher

2003-01-01

324

The manufacture and characterisation of hot-melt extruded enteric tablets.  

PubMed

The aim of this highly novel study was to use hot-melt extrusion technology as an alternative process to enteric coating. In so doing, oral dosage forms displaying enteric properties may be produced in a continuous, rapid process, providing significant advantages over traditional pharmaceutical coating technology. Eudragit L100-55, an enteric polymer, was pre-plasticized with triethyl citrate (TEC) and citric acid and subsequently dry-mixed with 5-aminosalicylic acid, a model active pharmaceutical ingredient (API), and an optional gelling agent (PVP K30 or Carbopol 971P). Powder blends were hot-melt extruded as cylinders, cut into tablets and characterised using powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC) and dissolution testing conducted in both pH 1.2 and pH 6.8 buffers. Increasing the concentration of TEC significantly lowered the glass transition temperature (Tg) of Eudragit L100-55 and reduced temperatures necessary for extrusion as well as the die pressure. Moreover, citric acid (17% w/w) was shown to act as a solid-state plasticizer. HME tablets showed excellent gastro-resistance, whereas milled extrudates compressed into tablets released more than 10% w/w of the API in acidic media. Drug release from HME tablets was dependent upon the concentration of TEC, the presence of citric acid, PVP K30, and Carbopol 971P in the matrix, and pH of the dissolution media. The inclusion of an optional gelling agent significantly reduced the erosion of the matrix and drug release rate at pH 6.8; however, the enteric properties of the matrix were lost due to the formation of channels within the tablet. Consequently this work is both timely and highly innovative and identifies for the first time a method of producing an enteric matrix tablet using a continuous hot-melt extrusion process. PMID:18164604

Andrews, Gavin P; Jones, David S; Diak, Osama Abu; McCoy, Colin P; Watts, Alan B; McGinity, James W

2008-05-01

325

Properties of hot-melt extruded tablet formulations for the colonic delivery of 5-aminosalicylic acid.  

PubMed

Hot-melt extruded tablets were prepared using Eudragit S 100 as the polymeric carrier to target delivery of 5-aminosalicylic acid (5-ASA) to the colon. Scanning electron microscopy, modulated differential scanning calorimetry and X-ray diffraction analysis of the hot-melt tablet extrudates demonstrated that 5-ASA remained crystalline and was homogeneously dispersed throughout the polymer matrix. A pre-plasticization step was necessary when incorporating triethyl citrate (TEC) into the formulation in order to achieve uniform mixing of the polymer and plasticizer, effectively reduce the polymer glass transition temperature (T(g)), and to lower the processing temperatures. The concentration of TEC in the extrudates not only influenced the processing temperature, but also influenced the drug release rates from the extruded tablets due to leaching of the TEC during dissolution testing. Citric acid monohydrate was found to plasticize Eudragit S 100, and when combined with TEC in the powder blend, the temperatures required for processing were reduced. Tablets containing citric acid released drug at a slower rate as a result of the suppression of polymer ionization due to a decrease in the micro-environmental pH of the tablet. The drug release profiles of the extruded tablets were found to fit both diffusion and surface erosion models. PMID:15567305

Bruce, L Diane; Shah, Navnit H; Malick, A Waseem; Infeld, Martin H; McGinity, James W

2005-01-01

326

Seletos 1 COMPARING NATIVE AND CROSS-PLATFORM DEVELOPMENT TABLET  

E-print Network

Seletos 1 COMPARING NATIVE AND CROSS-PLATFORM DEVELOPMENT TABLET ENVIRONMENTS BASED Term 2012 #12;Seletos 2 ABSTRACT Software development on tablet devices is very important. The leading tablet devices on the market are Google's Android tablet and Apple's iPad tablet. We

Miles, Will

327

Silicone adhesive matrix of verapamil hydrochloride to provide pH-independent sustained release.  

PubMed

Providing pH-independent oral release of weakly basic drugs with conventional matrix tablets can be challenging because of the pH-dependent solubility characteristics of the drugs and the changing pH environment along the gastrointestinal tract. The aim of the present study was to use a hydrophobic polymer to overcome the issue of pH-dependent release of weakly basic model drug verapamil hydrochloride from matrix tablets without the use of organic buffers in the matrix formulations. Silicone pressure-sensitive adhesive (PSA) polymer was evaluated because of its unique properties of low surface energy, hydrophobicity, low glass transition temperature, high electrical resistance, and barrier to hydrogen ion diffusion. Drug release, hydrogen ion diffusion, tablet contact angle, and internal tablet microenvironment pH with matrix tablets prepared using PSA were compared with those using water-insoluble ethyl cellulose (EC). Silicone PSA films showed higher resistance to hydrogen ion diffusion compared with EC films. Verapamil hydrochloride tablets prepared using silicone PSA showed higher hydrophobicity and lower water uptake than EC tablets. Silicone PSA tablets also showed pH-independent release of verapamil and decreased in dimensions during drug dissolution. By contrast, verapamil hydrochloride tablets prepared using EC did not achieve pH-independent release. PMID:24022347

Tolia, Gaurav; Li, S Kevin

2014-02-01

328

Floating units cut production costs  

SciTech Connect

Nine operating semisubmersible and tanker production platform facilities are currently supplying the technology and experiential data necessary for development of floating production systems for depth applications of 1000 to 10,000 ft. Sedco-Hamilton Production Services has developed a 4-well deepwater system consisting of a floating tanker or semi moored on short lines to 4 permanent catenary moored springbuoys. The platform is linked to a seabed tree array through the hull centerline via a flexible, retrievable production riser bundle. Costs associated with floating production platforms normally are lower than those of fixed platforms. A major factor is the decision to convert an existing drilling rig into the production mode or alternatively opt for a new build.

Homer, A.

1983-05-01

329

Profiling of Ecstasy Tablets Seized in Iran  

PubMed Central

In this study 50 samples of ecstasy tablets seized in Iran during the period of 2007 through 2008 were examined and their physical characteristics (appearance, marking, scored/not scored, color, weight, diameter, thickness) were determined. In order to determine the chemical characteristics of these tablets, color tests (Marquis test, Simon’s test, Chen’s test and Gallic acid test), Thin Layer Chromatography (TLC), anion test, residual solvents, Gas Chromatography-Mass Spectrometry (GC-MS) and Liquid Chromatography-Mass Spectrometry (LC-MS) were carried out on the tablets. The range of tablets weight was 96–308 mg and the range of 3,4-methylenedioxymethamphetamine (MDMA) hydrochloride content in these tablets was 60–180 mg. No good correlation was found between the tablets weight and their MDMA contents. All of the tablets containing MDMA had this compound in hydrochloride form. Ketamine, phenmetrazine and ephedrine (or pseudoephedrine) were found in some of the tablets along with MDMA. No MDMA was found in 20% of the tablets. Some of these tablets contained compounds such as caffeine or tramadol as their active ingredient. PMID:24250345

Khajeamiri, Ali Reza; Kobarfard, Farzad; Ahmadkhaniha, Reza; Mostashari, Gelareh

2011-01-01

330

14 CFR 29.521 - Float landing conditions.  

Code of Federal Regulations, 2013 CFR

...Requirements Water Loads § 29.521 Float landing conditions. If certification for float operation (including float amphibian operation) is requested, the rotorcraft, with floats, must be designed to withstand the following loading...

2013-01-01

331

14 CFR 29.521 - Float landing conditions.  

Code of Federal Regulations, 2012 CFR

...Requirements Water Loads § 29.521 Float landing conditions. If certification for float operation (including float amphibian operation) is requested, the rotorcraft, with floats, must be designed to withstand the following loading...

2012-01-01

332

14 CFR 29.521 - Float landing conditions.  

Code of Federal Regulations, 2010 CFR

...Requirements Water Loads § 29.521 Float landing conditions. If certification for float operation (including float amphibian operation) is requested, the rotorcraft, with floats, must be designed to withstand the following loading...

2010-01-01

333

14 CFR 29.521 - Float landing conditions.  

Code of Federal Regulations, 2014 CFR

...Requirements Water Loads § 29.521 Float landing conditions. If certification for float operation (including float amphibian operation) is requested, the rotorcraft, with floats, must be designed to withstand the following loading...

2014-01-01

334

14 CFR 29.521 - Float landing conditions.  

Code of Federal Regulations, 2011 CFR

...Requirements Water Loads § 29.521 Float landing conditions. If certification for float operation (including float amphibian operation) is requested, the rotorcraft, with floats, must be designed to withstand the following loading...

2011-01-01

335

Inverse differential casing cementing float valve  

SciTech Connect

This patent describes an inverse differential fill-up casing cementing float valve having an inlet thereto and outlet therefrom characterized in that the float valve permits fluid flow therethrough in a first direction upon a predetermined fluid pressure level thereacross and continuously prevents fluid flow therethrough in a second direction. The float valve includes: an annular float valve housing; a back pressure valve assembly contained within the annular float valve housing; a first differential pressure check valve assembly connected to the back pressure valve assembly and contained within the annular float valve housing; a second differential pressure check valve assembly connected to the first differential pressure check valve assembly and contained within the annular float valve housing; and cementitious filter material retaining and securing the back pressure valve assembly, the first differential pressure check valve assembly and the second differential pressure check valve assembly within the annular float valve housing.

Kuhlman, R.D. Jr.

1986-10-07

336

Floats, Integers, and Single Source Shortest Paths  

Microsoft Academic Search

Floats are ugly, but to everyone but theoretical computer scientists, they are the real thing. A linear time algorithm is presented for the undirected single-source shortest paths problem with nonnegative floating point weights.

Mikkel Thorup

2000-01-01

337

Tapered Floating Point: A New Floating-Point Representation  

Microsoft Academic Search

It is well known that there is a possible tradeoff in the binary representation of floating-point numbers in which one bit of accuracy can be gained at the cost of halving the exponent range, and vice versa. A way in which the exponent range can be greatly increased while preserving full accuracy for most computations is suggested.

ROBERT MORRIS

1971-01-01

338

Why do countries float the way they float?  

Microsoft Academic Search

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

Ricardo Hausmann; Ugo Panizza; Ernesto Stein

2001-01-01

339

Why Do Countries Float the Way They Float?  

Microsoft Academic Search

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

Ricardo Hausmann; Ugo G. Panizza; Ernesto Hugo Stein

2000-01-01

340

Implementation of float-float operators on graphics hardware  

Microsoft Academic Search

The Graphic Processing Unit (GPU) has evolved into a powerful and flexible processor. The latest graphic processors provide fully programmable vertex and pixel processing units that support vector operations up to single floating-point precision. This computational power is now being used for general-purpose computations. However, some applications require higher precision than single precision. This paper describes the emulation of a

Guillaume Da Graça; David Defour

2006-01-01

341

Attenuation of flexural vibration for floating floor and floating box induced by ground vibration  

Microsoft Academic Search

This paper investigates the vibration isolation performance of floating floor and floating box structures to control rail vibration transmission. Simple theoretical and experimental methods are developed to analyze the effects of stiffener beam, mass and arrangement of isolator on the fundamental natural frequency of the flexural vibration of floating floor and box structure.The vibration reduction performances of floating floor and

C. K. Hui; C. F. Ng

2009-01-01

342

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 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...

2014-07-01

343

Study on Influence of the Floating Ring in Floating Ring Bearing System under Turbulence State  

Microsoft Academic Search

The mechanism of a floating ring in the floating ring bearing system is investigated. Based on Hirs' bulk flow theory, Moody's frication factor equation and generalized incompressible Reynolds Equation, considering the elastic deformation and the whirling motion of the floating ring, the model and the governing equation of the floating ring bearing under the turbulence state were set up. The

Zhaohui Kang; Xingmin Ren; Zhi Wang; Shangwen He

2010-01-01

344

FloatOmeter: User-Friendly Input of Floating-Point Numbers in Virtual Environments  

E-print Network

FloatOmeter: User-Friendly Input of Floating-Point Numbers in Virtual Environments Matthias Kreiser, RI 02912 USA {kreiser,schulze,asf}@cs.brown.edu Specifying floating-point numbers in immersive. The most commonly used way to input floating-point numbers is by sliders. Sliders are widgets with a button

Schulze, Jürgen P.

345

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

E-print Network

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

California at Irvine, University of

346

21 CFR 520.2123a - Spectinomycin tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Spectinomycin tablets. 520.2123a Section 520.2123a Food...ANIMAL DRUGS § 520.2123a Spectinomycin tablets. (a) Specifications . Each tablet contains spectinomycin dihydrochloride...

2013-04-01

347

21 CFR 520.784 - Doxylamine succinate tablets.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

348

21 CFR 520.1720a - Phenylbutazone tablets and boluses.  

Code of Federal Regulations, 2011 CFR

... 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...

2011-04-01

349

21 CFR 520.623 - Diethylcarbamazine citrate, oxibendazole chewable tablets.  

Code of Federal Regulations, 2013 CFR

...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...

2013-04-01

350

21 CFR 520.1193 - Ivermectin tablets and chewables.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Ivermectin tablets and chewables. 520.1193 Section...ANIMAL DRUGS § 520.1193 Ivermectin tablets and chewables. (a) Specifications . (1) Each tablet or chewable contains 68, 136, or...

2011-04-01

351

21 CFR 520.2582 - Triflupromazine hydrochloride tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 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...

2012-04-01

352

21 CFR 520.622c - Diethylcarbamazine citrate chewable tablets.  

Code of Federal Regulations, 2012 CFR

...false Diethylcarbamazine citrate chewable tablets. 520.622c Section 520.622c Food...622c Diethylcarbamazine citrate chewable tablets. (a) Specifications. Each chewable tablet contains 30, 45, 60, 120, 150, or...

2012-04-01

353

21 CFR 520.2041 - Pyrantel pamoate chewable tablets.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

354

21 CFR 520.246 - Butorphanol tartrate tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 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...

2013-04-01

355

21 CFR 520.1720a - Phenylbutazone tablets and boluses.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 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...

2013-04-01

356

21 CFR 520.2123a - Spectinomycin tablets.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

357

21 CFR 520.434 - Chlorphenesin carbamate tablets.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Chlorphenesin carbamate tablets. 520.434 Section 520.434 Food and...DRUGS § 520.434 Chlorphenesin carbamate tablets. (a) Specifications. Each tablet contains 400 milligrams of chlorphenesin...

2011-04-01

358

21 CFR 520.1193 - Ivermectin tablets and chewables.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Ivermectin tablets and chewables. 520.1193 Section...ANIMAL DRUGS § 520.1193 Ivermectin tablets and chewables. (a) Specifications . (1) Each tablet or chewable contains 68, 136, or...

2013-04-01

359

21 CFR 520.2604 - Trimeprazine tartrate and prednisolone tablets.  

Code of Federal Regulations, 2012 CFR

...false Trimeprazine tartrate and prednisolone tablets. 520.2604 Section 520.2604 Food and...2604 Trimeprazine tartrate and prednisolone tablets. (a) Specifications. Each tablet contains: trimeprazine tartrate, 5...

2012-04-01

360

21 CFR 520.1242e - Levamisole hydrochloride effervescent tablets.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

361

21 CFR 520.246 - Butorphanol tartrate tablets.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

362

21 CFR 520.2123a - Spectinomycin tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Spectinomycin tablets. 520.2123a Section 520.2123a Food...ANIMAL DRUGS § 520.2123a Spectinomycin tablets. (a) Specifications. Each tablet contains spectinomycin dihydrochloride...

2014-04-01

363

21 CFR 520.863 - Ethylisobutrazine hydrochloride tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 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...

2013-04-01

364

21 CFR 520.2041 - Pyrantel pamoate chewable tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 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...

2013-04-01

365

21 CFR 520.784 - Doxylamine succinate tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 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...

2013-04-01

366

21 CFR 520.863 - Ethylisobutrazine hydrochloride tablets.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

367

21 CFR 520.1720a - Phenylbutazone tablets and boluses.  

Code of Federal Regulations, 2014 CFR

... 2014-04-01 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...

2014-04-01

368

21 CFR 520.2041 - Pyrantel pamoate chewable tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 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...

2012-04-01

369

21 CFR 520.1193 - Ivermectin tablets and chewables.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Ivermectin tablets and chewables. 520.1193 Section...ANIMAL DRUGS § 520.1193 Ivermectin tablets and chewables. (a) Specifications. (1) Each tablet or chewable contains 68, 136, or...

2014-04-01

370

21 CFR 520.1157 - Iodinated casein tablets.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Iodinated casein tablets. 520.1157 Section 520.1157 Food...ANIMAL DRUGS § 520.1157 Iodinated casein tablets. (a) Specifications. Each 1-gram tablet contains 25 milligrams of iodinated...

2011-04-01

371

21 CFR 520.2123a - Spectinomycin tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Spectinomycin tablets. 520.2123a Section 520.2123a Food...ANIMAL DRUGS § 520.2123a Spectinomycin tablets. (a) Specifications . Each tablet contains spectinomycin dihydrochloride...

2012-04-01

372

21 CFR 520.623 - Diethylcarbamazine citrate, oxibendazole chewable tablets.  

Code of Federal Regulations, 2012 CFR

...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...

2012-04-01

373

21 CFR 520.1157 - Iodinated casein tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Iodinated casein tablets. 520.1157 Section 520.1157 Food...ANIMAL DRUGS § 520.1157 Iodinated casein tablets. (a) Specifications. Each 1-gram tablet contains 25 milligrams of iodinated...

2013-04-01

374

21 CFR 520.622c - Diethylcarbamazine citrate chewable tablets.  

Code of Federal Regulations, 2014 CFR

...false Diethylcarbamazine citrate chewable tablets. 520.622c Section 520.622c Food...622c Diethylcarbamazine citrate chewable tablets. (a) Specifications. Each chewable tablet contains 30, 45, 60, 120, 150, or...

2014-04-01

375

21 CFR 520.623 - Diethylcarbamazine citrate, oxibendazole chewable tablets.  

Code of Federal Regulations, 2014 CFR

...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...

2014-04-01

376

21 CFR 520.863 - Ethylisobutrazine hydrochloride tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 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...

2014-04-01

377

21 CFR 520.434 - Chlorphenesin carbamate tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 false Chlorphenesin carbamate tablets. 520.434 Section 520.434 Food and...DRUGS § 520.434 Chlorphenesin carbamate tablets. (a) Specifications. Each tablet contains 400 milligrams of chlorphenesin...

2014-04-01

378

21 CFR 520.2098 - Selegiline hydrochloride tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 false Selegiline hydrochloride tablets. 520.2098 Section 520.2098 Food and...DRUGS § 520.2098 Selegiline hydrochloride tablets. (a) Specifications. Each tablet contains either 2, 5, 10, 15, or 30...

2014-04-01

379

21 CFR 520.784 - Doxylamine succinate tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 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...

2012-04-01

380

21 CFR 520.623 - Diethylcarbamazine citrate, oxibendazole chewable tablets.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

381

21 CFR 520.2610 - Trimethoprim and sulfadiazine tablets.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Trimethoprim and sulfadiazine tablets. 520.2610 Section 520.2610 Food and...520.2610 Trimethoprim and sulfadiazine tablets. (a) Specifications. Each tablet contains 30 milligrams (5...

2011-04-01

382

21 CFR 520.2610 - Trimethoprim and sulfadiazine tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Trimethoprim and sulfadiazine tablets. 520.2610 Section 520.2610 Food and...520.2610 Trimethoprim and sulfadiazine tablets. (a) Specifications. Each tablet contains 30 milligrams (5...

2012-04-01

383

21 CFR 520.2123a - Spectinomycin tablets.  

Code of Federal Regulations, 2010 CFR

...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...

2010-04-01

384

21 CFR 520.2582 - Triflupromazine hydrochloride tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 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...

2013-04-01

385

21 CFR 520.1157 - Iodinated casein tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 false Iodinated casein tablets. 520.1157 Section 520.1157 Food...ANIMAL DRUGS § 520.1157 Iodinated casein tablets. (a) Specifications. Each 1-gram tablet contains 25 milligrams of iodinated...

2014-04-01

386

21 CFR 529.400 - Chlorhexidine tablets and suspension.  

Code of Federal Regulations, 2011 CFR

... 2011-04-01 false Chlorhexidine tablets and suspension. 529.400 Section 529...ANIMAL DRUGS § 529.400 Chlorhexidine tablets and suspension. (a) Specification. Each tablet and each 28-milliliter syringe of...

2011-04-01

387

21 CFR 520.246 - Butorphanol tartrate tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 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...

2012-04-01

388

21 CFR 520.2610 - Trimethoprim and sulfadiazine tablets.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Trimethoprim and sulfadiazine tablets. 520.2610 Section 520.2610 Food and...520.2610 Trimethoprim and sulfadiazine tablets. (a) Specifications. Each tablet contains 30 milligrams (5...

2010-04-01

389

EXPERIENCE WITH TABLET PC VIDEO BASED HYBRID COURSEWORK IN  

E-print Network

EXPERIENCE WITH TABLET PC VIDEO BASED HYBRID COURSEWORK IN COMPUTER SCIENCE Jaspal Subhlok, Olin Keywords: Hybrid Learning, Online Learning, Video Lectures, Tablet PC Abstract Online learning, defined classroom interaction is detrimental to learning. Employing Tablet PCs with slide presentation

Subhlok, Jaspal

390

21 CFR 520.863 - Ethylisobutrazine hydrochloride tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 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...

2012-04-01

391

21 CFR 520.2041 - Pyrantel pamoate chewable tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 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...

2014-04-01

392

21 CFR 520.784 - Doxylamine succinate tablets.  

Code of Federal Regulations, 2010 CFR

...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...

2010-04-01

393

21 CFR 520.784 - Doxylamine succinate tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 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...

2014-04-01

394

21 CFR 520.2604 - Trimeprazine tartrate and prednisolone tablets.  

Code of Federal Regulations, 2013 CFR

...false Trimeprazine tartrate and prednisolone tablets. 520.2604 Section 520.2604 Food and...2604 Trimeprazine tartrate and prednisolone tablets. (a) Specifications. Each tablet contains: trimeprazine tartrate, 5...

2013-04-01

395

21 CFR 520.2604 - Trimeprazine tartrate and prednisolone tablets.  

Code of Federal Regulations, 2014 CFR

...false Trimeprazine tartrate and prednisolone tablets. 520.2604 Section 520.2604 Food and...2604 Trimeprazine tartrate and prednisolone tablets. (a) Specifications. Each tablet contains: trimeprazine tartrate, 5...

2014-04-01

396

21 CFR 520.434 - Chlorphenesin carbamate tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Chlorphenesin carbamate tablets. 520.434 Section 520.434 Food and...DRUGS § 520.434 Chlorphenesin carbamate tablets. (a) Specifications. Each tablet contains 400 milligrams of chlorphenesin...

2013-04-01

397

21 CFR 520.1446 - Milbemcyin oxime and lufenuron tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 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)...

2012-04-01

398

21 CFR 520.1157 - Iodinated casein tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Iodinated casein tablets. 520.1157 Section 520.1157 Food...ANIMAL DRUGS § 520.1157 Iodinated casein tablets. (a) Specifications. Each 1-gram tablet contains 25 milligrams of iodinated...

2012-04-01

399

21 CFR 520.434 - Chlorphenesin carbamate tablets.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Chlorphenesin carbamate tablets. 520.434 Section 520.434 Food and...DRUGS § 520.434 Chlorphenesin carbamate tablets. (a) Specifications. Each tablet contains 400 milligrams of chlorphenesin...

2010-04-01

400

21 CFR 520.1242e - Levamisole hydrochloride effervescent tablets.  

Code of Federal Regulations, 2014 CFR

...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...

2014-04-01

401

21 CFR 520.863 - Ethylisobutrazine hydrochloride tablets.  

Code of Federal Regulations, 2010 CFR

...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...

2010-04-01

402

21 CFR 520.246 - Butorphanol tartrate tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 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...

2014-04-01

403

21 CFR 520.622c - Diethylcarbamazine citrate chewable tablets.  

Code of Federal Regulations, 2013 CFR

...false Diethylcarbamazine citrate chewable tablets. 520.622c Section 520.622c Food...622c Diethylcarbamazine citrate chewable tablets. (a) Specifications. Each chewable tablet contains 30, 45, 60, 120, 150, or...

2013-04-01

404

21 CFR 529.400 - Chlorhexidine tablets and suspension.  

Code of Federal Regulations, 2012 CFR

... 2012-04-01 false Chlorhexidine tablets and suspension. 529.400 Section 529...ANIMAL DRUGS § 529.400 Chlorhexidine tablets and suspension. (a) Specification. Each tablet and each 28-milliliter syringe of...

2012-04-01

405

21 CFR 520.2582 - Triflupromazine hydrochloride tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 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...

2014-04-01

406

21 CFR 529.400 - Chlorhexidine tablets and suspension.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 false Chlorhexidine tablets and suspension. 529.400 Section 529...ANIMAL DRUGS § 529.400 Chlorhexidine tablets and suspension. (a) Specification. Each tablet and each 28-milliliter syringe of...

2010-04-01

407

21 CFR 520.1720a - Phenylbutazone tablets and boluses.  

Code of Federal Regulations, 2010 CFR

... 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...

2010-04-01

408

Prototyping Hybrid Musical Interactions on Tablet Devices Henri Palleis  

E-print Network

Prototyping Hybrid Musical Interactions on Tablet Devices Henri Palleis Ludwig interactions on tablet devices that combine tangible, touch and gestural input. Existing low the rapid exploration of hybrid musical interaction concepts on tablet devices with capacitive touchscreens

409

21 CFR 520.1193 - Ivermectin tablets and chewables.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Ivermectin tablets and chewables. 520.1193 Section...ANIMAL DRUGS § 520.1193 Ivermectin tablets and chewables. (a) Specifications . (1) Each tablet or chewable contains 68, 136, or...

2010-04-01

410

21 CFR 529.400 - Chlorhexidine tablets and suspension.  

Code of Federal Regulations, 2014 CFR

... 2014-04-01 false Chlorhexidine tablets and suspension. 529.400 Section 529...ANIMAL DRUGS § 529.400 Chlorhexidine tablets and suspension. (a) Specification. Each tablet and each 28-milliliter syringe of...

2014-04-01

411

21 CFR 520.2610 - Trimethoprim and sulfadiazine tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 false Trimethoprim and sulfadiazine tablets. 520.2610 Section 520.2610 Food and...520.2610 Trimethoprim and sulfadiazine tablets. (a) Specifications. Each tablet contains 30 milligrams (5...

2014-04-01

412

21 CFR 520.434 - Chlorphenesin carbamate tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Chlorphenesin carbamate tablets. 520.434 Section 520.434 Food and...DRUGS § 520.434 Chlorphenesin carbamate tablets. (a) Specifications. Each tablet contains 400 milligrams of chlorphenesin...

2012-04-01

413

21 CFR 520.1720a - Phenylbutazone tablets and boluses.  

Code of Federal Regulations, 2012 CFR

... 2012-04-01 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...

2012-04-01

414

21 CFR 520.1193 - Ivermectin tablets and chewables.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Ivermectin tablets and chewables. 520.1193 Section...ANIMAL DRUGS § 520.1193 Ivermectin tablets and chewables. (a) Specifications . (1) Each tablet or chewable contains 68, 136, or...

2012-04-01

415

21 CFR 520.2582 - Triflupromazine hydrochloride tablets.  

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

416

21 CFR 529.400 - Chlorhexidine tablets and suspension.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 false Chlorhexidine tablets and suspension. 529.400 Section 529...ANIMAL DRUGS § 529.400 Chlorhexidine tablets and suspension. (a) Specification. Each tablet and each 28-milliliter syringe of...

2013-04-01

417

21 CFR 520.1446 - Milbemcyin oxime and lufenuron tablets.  

Code of Federal Regulations, 2011 CFR

...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)...

2011-04-01

418

21 CFR 520.1696d - Penicillin V potassium tablets.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Penicillin V potassium tablets. 520.1696d...ANIMAL DRUGS § 520.1696d Penicillin V potassium tablets. (a) Specifications. Each tablet contains penicillin V potassium equivalent to...

2012-04-01

419

21 CFR 520.1696d - Penicillin V tablets.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Penicillin V tablets. 520.1696d Section...NEW ANIMAL DRUGS § 520.1696d Penicillin V tablets. (a) Specifications. Each tablet contains penicillin V potassium equivalent to 125...

2014-04-01

420

21 CFR 520.1696d - Penicillin V potassium tablets.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Penicillin V potassium tablets. 520.1696d...ANIMAL DRUGS § 520.1696d Penicillin V potassium tablets. (a) Specifications. Each tablet contains penicillin V potassium equivalent to...

2010-04-01

421

21 CFR 520.1696d - Penicillin V potassium tablets.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Penicillin V potassium tablets. 520.1696d...ANIMAL DRUGS § 520.1696d Penicillin V potassium tablets. (a) Specifications. Each tablet contains penicillin V potassium equivalent to...

2011-04-01

422

21 CFR 520.1696d - Penicillin V tablets.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Penicillin V tablets. 520.1696d Section...NEW ANIMAL DRUGS § 520.1696d Penicillin V tablets. (a) Specifications. Each tablet contains penicillin V potassium equivalent to 125...

2013-04-01

423

Wave attenuation characteristics of a tethered float system  

Microsoft Academic Search

Wave attenuation characteristics of a tethered float system have been investigated for various wave heights, wave periods, water depths, depths of submergence of floats and float sizes. As the floats are similar in size and shape, only a single tethered spherical float is considered for the theoretical analysis. Float motion is determined through the dynamical equation of motion, developed for

P. Vethamony

1995-01-01

424

32 CFR 935.165 - Floating objects.  

Code of Federal Regulations, 2014 CFR

...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...

2014-07-01

425

Floating Content: Information Sharing in Urban Areas  

E-print Network

Floating Content: Information Sharing in Urban Areas J¨org Ott, Esa Hyyti¨a, Pasi Lassila Aalto. The net result is a best effort service for floating content in which: 1) information dissemination for floating content, which, at the same time also validate the analytical results obtained for a more abstract

Ott, Jörg

426

Multiplications of floating point expansions Marc Daumas  

E-print Network

Multiplications of floating point expansions Marc Daumas CNRS - Lab LIP - UMR 8512 - ENS de Lyon computers, the floating point unit is the part of the processor delivering the highest computing power will be dramatically enhanced by adequate use of floating point expansions. We present in this work three

California at Davis, University of

427

Optimistic Parallelization of Floating-Point Accumulation  

E-print Network

Optimistic Parallelization of Floating-Point Accumulation Nachiket Kapre Computer Science and Systems Engineering University of Pennsylvania Philadelphia, PA 19104 andre@acm.org Abstract-- Floating intermediate values be rounded to fit in the available precision. The resulting cyclic dependency in floating

California at Davis, University of

428

Compensated algorithms in floating point arithmetic  

E-print Network

Compensated algorithms in floating point arithmetic: accuracy, validation, performances. Nicolas ´Equipe DALI N. Louvet (Universit´e de Perpignan) Nicolas Louvet ­ Compensated algorithms in floating of errors when computing the solution of a scientific problem in floating point arithmetic: mathematical

Louvet, Nicolas

429

Floating-Point Arithmetic Precision and Accuracy  

E-print Network

Floating-Point Arithmetic Precision and Accuracy With Mathematica Alkis Akritas University is to approximate the real numbers using the finite set of floating-point numbers. Mathematica has two kinds of floating-point numbers: machine- precision numbers and arbitrary-precision numbers. (The precision

Akritas, Alkiviadis G.

430

Floating Content: Information Availability in Urban Environments  

E-print Network

Floating Content: Information Availability in Urban Environments Jussi Kangasharju University networking. The net result is a best effort service for floating content in which: 1) information be added, but not deleted. We present the general model for floating content and results from our on

Ott, Jörg

431

Accurate floating point summation James Demmel  

E-print Network

Accurate floating point summation James Demmel Yozo Hida May 8, 2002 Abstract We present and analyze several simple algorithms for accurately summing n floating point numbers S = n i=1 si precision only (F 2f). We apply this result to the floating point formats in the (proposed revision of the

California at Berkeley, University of

432

Initial stages of float glass corrosion  

Microsoft Academic Search

The differences between the corrosion process of the bath and the top side of float glass and the dependence on the corrosion process on the thickness of the glass could be demonstrated by ellipsometric measurements of defined corroded float glasses. The effectiveness of different cleaning procedures on corroded float glass surfaces is discussed. Ellipsometry can help determine suitable separating agent

M. Feldmann; R. Wei?mann

1997-01-01

433

Floating Point Numbers Review of Numbers  

E-print Network

Floating Point Numbers #12;2 Review of Numbers Computers are made to deal with numbers What can we notation #12;3 Scientific Notation: Review 6.02 x 1023 radix (base)decimal point mantissa exponent Declare such variable in C as float #12;5 Floating Point (FP) Representation (1/2) Normal format: +1

Delgado-Frias, José G.

434

The fluid mechanics of floating and sinking  

E-print Network

objects can float at an interface between two fluids. We obtain the conditions on density and size for various objects to float and show that being ‘super-hydrophobic’ does not generally help small, dense objects to float. Super-hydrophobicity does...

Vella, Dominic Joseph Robert

2007-10-02

435

Have Floating Rates Been a Success?  

ERIC Educational Resources Information Center

Floating exchange rates have not lived up to all expectations, but neither have they performed as badly as some critics have suggested. Examined are the impact of floating rates on balance of payments adjustment, domestic economic policy, and inflation and the claim that floating rates have displayed excessive fluctuations. (Author/RM)

Higham, David

1983-01-01

436

Floats, Integers, and Single Source Shortest Paths  

Microsoft Academic Search

Floats are ugly, but to everyone but theoretical computer scientists, they are thereal thing. A linear time algorithm is presented for the undirected single source shortestpaths problem with positive floating point weights.1 IntroductionThe technical goal of this paper is to present a linear time solution to the undirected singlesource shortest paths problem (USSSP) where the weights are positive floating points,

Mikkel Thorup

1998-01-01

437

Preformulation studies of mucoadhesive tablets for carbamazepine sublingual administration.  

PubMed

The purpose of this research work was the realization of a bi-layered mucoadhesive dosage form intended for carbamazepine sublingual administration and planned in order to obtain a unidirectional drug release and diffusion only across buccal mucosa avoiding the liberation in the buccal environment. Bi-layered tablets were constituted by an impermeable ethyl cellulose backing layer and a mucoadhesive layer. The latter was composed by a blend of a semisynthetic polymer, as hydroxyethyl cellulose or hydroxypropyl methylcellulose, and a synthetic polymer as, Carbopol(®), physically mixed in different ratios. The active ingredient carbamazepine was homogeneously dispersed in the mucoadhesive layer. The prepared formulations were carefully characterized by thickness, friability, swelling index, matrix erosion, ex vivo and in vivo mucoadhesive force and time, moreover patient acceptability was evaluated as well. Tablets constituted by Carbopol(®):hydroxypropyl methylcellulose (25%:75%) and Carbopol(®):hydroxyethyl cellulose (75%:25%) showed the best properties and for this reason were submitted to in vitro release studies. Both tablet groups gave good results in terms of ex vivo and in vivo bioadhesive force and time giving a sustained release. PMID:23124021

Perioli, Luana; Pagano, Cinzia

2013-02-01

438

Suminagashi: Floating Ink Paper Marbling  

NSDL National Science Digital Library

In this activity, learners try to float ink on the surface of water to create a pattern and then capture it with absorbent paper. This technique, called Suminagashi, is an ancient Japanese style of decorating paper with inks and believed to be the oldest form of marbling. This art activity can introduce learners to fluid mechanics, viscosity, and surface tension.

2012-06-26

439

Airship-floated wind turbine  

Microsoft Academic Search

A wind turbine, by use of a tethered airship for support, may be designed for the economical recovery of power at heights of 2,000 feet or more above ground, at which height power density in the wind is typically three times the power density available to a conventionally supported wind turbine. Means can be added to such an airship-floated wind

1985-01-01

440

Tablet Content Analysis Using Terahertz Transmission Spectroscopy  

Microsoft Academic Search

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

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

2007-01-01

441

Evaluation of quick disintegrating calcium carbonate tablets  

Microsoft Academic Search

The purpose of this investigation was to develop a rapidly disintegrating calcium carbonate (CC) tablet by direct compression\\u000a and compare it with commercially available calcium tablets. CC tablets were formulated on a Carver press using 3 different\\u000a forms of CC direct compressed granules (Cal-Carb 4450®, Cal-Carb 4457®, and Cal-Carb 4462®). The breaking strength was measured using a Stokes-Monsanto hardness tester.

Hector Fausett; Charles Gayser Jr; Alekha K. Dash

2000-01-01

442

The Venus Tablet and Refraction  

E-print Network

It is shown that the refraction near the horizon is introducing an additional bias into the Venus Tablet of Ammisaduqa, which is able to influence the interpretation of the data. We then discuss the attempts to link certain solar eclipses to the birth of Shamshi-Adad and conclude that a record of a single solar eclipse without description of details and/or unambiguous historical links, can hardly act as a reliable anchor.

Gurzadyan, V G

2003-01-01

443

Mucoadhesive tablets for controlled release of acyclovir.  

PubMed

Mucoadhesive chitosan (CS) and/or hydroxypropyl-methylcellulose (HPMC) tablets for gastric drug delivery of acyclovir (ACV) have been developed in order to improve the ACV oral bioavailability. Swelling, bioadhesive and dissolution studies were carried out in two acidic media (pH 1.5 and 4) in order to determine the tablets behaviour in both fed and fasted states. All the designed tablets showed good mucoadhesive properties on gastric mucosa due to the presence of CS and/or HPMC. In vitro dissolution of ACV from tablets was influenced by the swelling behaviour of each polymer. All data release of the studied tablets fitted to Hopfenberg model, which describes drug release from tablets displaying heterogeneous erosion. HPMC and CS/HPMC tablets revealed a sustained release for 24 h, but a complete dissolution of the tablets was not produced at this time. On the contrary, tablets which contained only CS as polymer were able to release the total amount of ACV for 4 h, due to the CS imbibition and erosion processes in pH 1.5 medium. These results allowed us to conclude that CS is the excipient to be chosen to obtain gastroretentive formulations, due to its demonstrated gastric compatibility. PMID:22863800

Ruiz-Caro, Roberto; Gago-Guillan, Manuel; Otero-Espinar, Francisco Javier; Veiga, María Dolores

2012-01-01

444

Balloons and Other Things That Sometimes Float  

NSDL National Science Digital Library

Hot air balloons float--sometimes. Regular old balloons that you get at a party float--sometimes. Boats float--sometimes. What makes them float and what makes them sink? How can a boat made of steel float but a solid chunk of steel sink to the bottom of the ocean? Part of the answer has to do with something called density, which will be discussed in this chapter. And yes, the concepts addressed in this chapter do have a lot to do with weather.

2005-01-01

445

TO FLOAT OR NOT TO FLOAT? CURRENCY REGIMES AND GROWTH  

Microsoft Academic Search

One recent line of research on exchange rates is the effect of fixed or floating currencies on long-term growth. One difficulty with such studies is that emerging market countries with certain imbalances and potentially hard-to-observe policy distortions are more likely to choose a fixed exchange rate regime, and thus estimates of the effect of exchange rates on growth are likely

William Miles

2006-01-01

446

Tablet PCs: A Physical Educator's New Clipboard  

ERIC Educational Resources Information Center

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…

Nye, Susan B.

2010-01-01

447

Enhancing Student Performance Using Tablet Computers  

ERIC Educational Resources Information Center

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…

Enriquez, Amelito G.

2010-01-01

448

Time to stop counting the tablets?  

Microsoft Academic Search

We attempted to assess compliance using both a pharmacologic indicator (low-dose phenobarbital) and a return tablet count in 225 patients who were taking part in three separate studies. There were 216 patients (96%) who kept a follow-up appointment after 28 days; 161 patients appeared to have good compliance (90% to 109%) by return tablet count. Of these 161 patients, 51

Thomas Pullar; Shubha Kumar; Hilary Tindall; Morgan Feely

1989-01-01

449

Putting Tablet PCs to the Test  

ERIC Educational Resources Information Center

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…

Amirian, Susan

2004-01-01

450

Float zone experiments in space  

NASA Technical Reports Server (NTRS)

The molten zone/freezing crystal interface system and all the mechanisms were examined. If Marangoni convection produces oscillatory flows in the float zone of semiconductor materials, such as silicon, then it is unlikely that superior quality crystals can be grown in space using this process. The major goals were: (1) to determine the conditions for the onset of Marangoni flows in molten tin, a model system for low Prandtl number molten semiconductor materials; (2) to determine whether the flows can be suppressed by a thin oxide layer; and (3) based on experimental and mathematical analysis, to predict whether oscillatory flows will occur in the float zone silicon geometry in space, and if so, could it be suppressed by thin oxide or nitride films. Techniques were developed to analyze molten tin surfaces in a UHV system in a disk float zone geometry to minimize buoyancy flows. The critical Marangoni number for onset of oscillatory flows was determined to be greater than 4300 on atomically clean molten tin surfaces.

Verhoeven, J. D.; Noack, M. A.; Gill, W. N.; Hau, C. C.

1984-01-01

451

Gastric emptying of enteric-coated tablets  

SciTech Connect

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.

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

1984-03-01

452

Smartphones and tablets: Reshaping radiation oncologists’ lives  

PubMed Central

Background Smartphones and tablets are new handheld devices always connected to an information source and capable of providing instant updates, they allow doctors to access the most updated information and provide decision support at the point of care. Aim The practice of radiation oncology has always been a discipline that relies on advanced technology. Smartphones provide substantial processing power, incorporating innovative user interfaces and applications. Materials and methods The most popular smartphone and tablet app stores were searched for “radiation oncology” and “oncology” related apps. A web search was also performed searching for smartphones, tablets, oncology, radiology and radiation oncology. Results Smartphones and tablets allow rapid access to information in the form of podcasts, apps, protocols, reference texts, recent research and more. Conclusion With the rapidly changing advances in radiation oncology, the trend toward accessing resources via smartphones and tablets will only increase, future will show if this technology will improve clinical care. PMID:24669308

Gomez-Iturriaga, Alfonso; Bilbao, Pedro; Casquero, Francisco; Cacicedo, Jon; Crook, Juanita

2012-01-01

453

Application of Design of Experiment for Polyox and Xanthan Gum Coated Floating Pulsatile Delivery of Sumatriptan Succinate in Migraine Treatment  

PubMed Central

Migraine follows circadian rhythm in which headache is more painful at the awakening time. This needs administration of dosage form at night time to release drug after lag period when pain gets worse. Sumatriptan succinate is a drug of choice for migraine. Sumatriptan succinate has bitter taste, low oral bioavailability, and shorter half-life. Present work deals with application of design of experiment for polyox and xanthan gum in development of press coated floating pulsatile tablet. Floating pulsatile concept was applied to increase gastric residence of the dosage form. Burst release was achieved through immediate release tablet using crospovidone as superdisintegrant (10%). Pulse lag time was achieved using swellable polymer polyox WSR 205 and xanthan gum. 32 experimental design was applied. Optimized formulation was evaluated for physical characteristics and in-vitro and in-vivo study. From results, it can be concluded that optimized batch F8 containing polyox WSR205 (72.72%) and xanthan gum (27.27%) of total weight of polymer has shown floating lag time of 55 ± 2?sec, drug content of 100.35 ± 0.4%, hardness of 6 ± 0.1?Kg/cm2, and 98.69 ± 2% drug release in pulse manner with lag time of 7 ± 0.1?h. Optimized batch showed prolong gastric residence which was confirmed by in-vivo X-ray study. PMID:25530963

Jagdale, Swati C.; Pawar, Chandrakala R.

2014-01-01

454

The feature rich tablet designed to keep you constantly connected  

E-print Network

VenueTM 8 The feature rich tablet designed to keep you constantly connected A tablet for everyone Whatever you are looking for in a tablet, we definitely have your type. The Dell VenueTM 8 is both flexible Dell tablets are designed for easy integration with an array of accessories. With the new Dell Venue

Fiebig, Peter

455

The effect of HPMC particle size on the drug release rate and the percolation threshold in extended-release mini-tablets.  

PubMed

The particle size of HPMC is a critical factor that can influence drug release rate from hydrophilic matrix systems. Percolation theory is a statistical tool which is used to study the disorder of particles in a lattice of a sample. The percolation threshold is the point at which a component is dominant in a cluster resulting in significant changes in drug release rates. Mini-tablets are compact dosage forms of 1.5-4?mm diameter, which have potential benefits in the delivery of drug to some patient groups such as pediatrics. In this study, the effect of HPMC particle size on hydrocortisone release and its associated percolation threshold for mini-tablets and tablets was assessed. For both mini-tablets and tablets, large polymer particles reduced tensile strength, but increased the drug release rate and the percolation threshold. Upon hydration, compacts with 45-125??m HPMC particles formed a strong gel layer with low porosity, reducing hydrocortisone release rates. In comparison, faster drug release rates were obtained when 125-355?µm HPMC particles were used, due to the greater pore sizes that resulted in the formation of a weaker gel. Using 125-355?µm HPMC particles increased the percolation threshold for tablets and to a greater extent for mini-tablets. This work has demonstrated the importance of HPMC particle size in ER matrices, the effects of which are even more obvious for mini-tablets. PMID:24134563

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

2015-01-01

456

Phase transformation in thiamine hydrochloride tablets: Influence on tablet microstructure, physical properties, and performance.  

PubMed

The objective of this article was to monitor phase transformation in thiamine hydrochloride, from a nonstoichiometric hydrate (NSH) to a hemihydrate (HH), in stored tablets, prepared both by direct compression and wet granulation, and to relate the storage-induced phase transformation with changes in tablet microstructure, physical properties, and performance. Raman spectroscopy revealed complete NSH ? HH transformation in tablets, within 30 h of storage at 40°C/75% relative humidity. When the tablets were prepared by wet granulation of NSH alone, there was a marked increase in both tablet volume and hardness on storage. However, when microcrystalline cellulose (MCC) was included in granulation, the resulting stored tablets also exhibited a pronounced increase in disintegration time. In contrast, tablets prepared by dry processing via compression of a NSH-MCC physical mixture did not exhibit any changes in properties, despite the in situ solid form conversion. Scanning electron microscopy revealed growth of needle-like HH crystals in all stored tablets and mercury porosimetry revealed considerable changes in the pore size distribution during storage. Longer storage led to crystal growth (Ostwald ripening), causing further gradual but less dramatic changes in properties. The phase transformation and the complex interparticulate associations in the tablet influenced the changes in tablet microstructure, compact physical properties, and product behavior. PMID:22213350

Chakravarty, Paroma; Suryanarayanan, Raj; Govindarajan, Ramprakash

2012-04-01

457

Condition and Error Estimates in Numerical Matrix Computations  

SciTech Connect

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.

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

458

The impact of floating migration on fertility in China: are floating migrants "childbearing guerillas"?  

E-print Network

The increasing number of floating migrants in the big cities of China is the result of the household registration (hukou) system and the fast growing market-economy in China. The mass media have portrayed floating migrants as "childbearing...

You, Xiuhong

2002-01-01

459

Relational Abstract Domains for the Detection of Floating-Point  

E-print Network

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

Miné, Antoine

460

Intel I/O, Floating point o DOS System Calls  

E-print Network

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

Biagioni, Edoardo S.

461

Novel floating FDNR, inductor and capacitor simulator using CBTA  

Microsoft Academic Search

In this study novel floating frequency dependent negative resistor (FDNR), floating inductor (FI), floating capacitor and floating resistor simulator circuit employing two CBTAs and three passive components is proposed. The presented circuit can realize floating FDNR, inductor, capacitor or resistor depending on the passive component selection. Since the passive elements are all grounded, this circuit is suitable for fully integrated

Umut Engin Ayten; Mehmet Sagbas; Norbert Herencsar; Jaroslav Koton

2011-01-01

462

The impact on seaplane floats during landing  

NASA Technical Reports Server (NTRS)

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.

Von Karman, TH

1929-01-01

463

Tank Tests of Twin Seaplane Floats  

NASA Technical Reports Server (NTRS)

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.

Herrman, H; Kempf, G; Kloess, H

1928-01-01

464

Design and optimization of sustained-release divalproex sodium tablets with response surface methodology.  

PubMed

Response surface methodology is defined as a collection of mathematical and statistical methods that are used to develop, improve, or optimize a product or process. In the present study, a statistical design (Mixture Design) was employed for formulation and optimization of a sustained-release hydrophilic divalproex sodium matrix tablet. Different excipients were used to improve the drug's poor flowability. The hardness of the prepared tablets and also their release pattern were tested. The formulation design was carried out employing mixture design using four excipients in three levels. The Carr's index of formulations and tensile strength were determined and analyzed using Minitab software. The suitable formulations regarding flowability and tablet tensile strength were selected by this software for subsequent drug release studies. The dissolution tests were carried out in acidic and basic phases which were previously proved to be biomimetic. Samples were analyzed using HPLC, and release data were compared to Depakine® (sustained-release divalproex from Sanofi). Release kinetics was also determined for selected formulations. Selected formulations were subjected to dissolution test and showed similar dissolution profiles with Depakine® based on difference and similarity factor calculations. The software selected an optimized formulation which had a slightly different release pattern in vitro compared to innovator but of nearly zero-order kinetics. It can be concluded that application of Mixture Design is a shortcut method to design suitable formulations of sustained-release divalproex sodium containing hydrophilic matrix tablets by direct compression method. PMID:23269542

Monajjemzadeh, Farnaz; Hamishehkar, Hamed; Zakeri-Milani, Parvin; Farjami, Afsaneh; Valizadeh, Hadi

2013-03-01

465

Modeling International Space Station (ISS) Floating Potentials  

NASA Technical Reports Server (NTRS)

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.

Ferguson, Dale C.; Gardner, Barbara

2002-01-01

466

Floating Ice-Algal Aggregates below Melting Arctic Sea Ice  

PubMed Central

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

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

467

Floating ice-algal aggregates below melting arctic sea ice.  

PubMed

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

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

468

Barotropic ocean velocity observations from an electric field float, a modified RAFOS float  

Microsoft Academic Search

A seldom observed characteristic of ocean motion is depth-averaged velocity, or transport per unit width. One approach to observing this quantity is to measure the ambient horizontal electric field of the ocean with electric field sensors added to a RAFOS float. The Electric Field Float (EFF) is a RAFOS float modified by the addition of a compass, electrode arms, amplifiers,

Thomas B. Sanford; R. G. Drever; J. H. Dunlap

1995-01-01

469

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 false External floating roof converted into an internal...RULE Storage Vessels § 65.45 External floating roof converted into an internal...regulated material emissions by using an external floating roof converted into an...

2010-07-01

470

Floating patella associated with lymphoedema.  

PubMed

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

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

2015-01-01

471

Algorithms for Arbitrary Precision Floating Point Arithmetic \\Lambda  

E-print Network

Algorithms for Arbitrary Precision Floating Point Arithmetic \\Lambda Douglas M. Priest Department to perform computations of very high accuracy using only straightforward floating point arithmetic operations satisfied by most implementations of floating point arithmetic. To illustrate the application

Shewchuk, Jonathan

472

Monte Carlo Arithmetic: exploiting randomness in floating-point arithmetic  

E-print Network

Monte Carlo Arithmetic: exploiting randomness in floating Abstract Monte Carlo Arithmetic (MCA) is an extension of standard floating-point * *arithmetic that exploits randomness in basic floating-point operations. MCA includes rando* *m rounding _ which

Parker, D. Stott

473

Floating point verification in HOL Light: the exponential function  

E-print Network

Floating point verification in HOL Light: the exponential function, operations for computing the common transcendental functions in floating point arithmetic seem good floating point arithmetic. We confirm (indeed strengthen) the main result of a previously published

Haddadi, Hamed

474

33 CFR 143.120 - Floating OCS facilities.  

Code of Federal Regulations, 2014 CFR

...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...

2014-07-01

475

Smooth Planning for Free-floating Space Robots Using Polynomials *  

E-print Network

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

Papadopoulos, Evangelos

476

Resistant starch as a carrier for oral colon-targeting drug matrix system  

Microsoft Academic Search

In this study, a novel tablet of protein drug matrix for colon targeting was developed using resistant starch as a carrier\\u000a prepared by pre-gelatinization and cross-linking of starch. The effects of pre-gelatinization and cross-linking on the swelling\\u000a and enzymatic degradation of maize starch as well as the release rate of drug from the matrix tablets were examined. Cross-linked\\u000a pre-gelatinized maize

Ling Chen; Xiaoxi Li; Yansheng Pang; Lin Li; Ximei Zhang; Long Yu

2007-01-01

477

High performance reconfigurable floating-point arithmetic modules  

Microsoft Academic Search

This paper presents the design, optimization and implementation of floating- point arithmetic modules on FPGA to be used in DSP appkications. These modules are floating-point multiplier, floating-point adderhbtractor, floating-point complex multiplier, floating-point complex adder\\/subtractor and floating-point multiplier-accumulator (MAC). The simulation and the Synthesis results for these modules are provided. All the modules presented in this paper support creation of custom

Ghd A. Aty; I. S. Ashour; M. Mones

2005-01-01

478

Comparative evaluation of drug release from aged prolonged polyethylene oxide tablet matrices: effect of excipient and drug type.  

PubMed

Abstract Polyethylene oxide (PEO) undergoes structural adjustments caused by elevated temperatures, which results in loss of its stability within direct compression tablets. The aim of this study was to evaluate the influence of filler solubility on the drug delivery process of matrix tablets containing drugs with different water-solubility properties and stored at elevated temperature. The results demonstrated that in the case of propranolol HCl (highly water-soluble) tablet matrices, soluble lactose promoted drug release, whereas, a stable release of drug was observed with insoluble DCP. A drug release pattern similar to the propranolol HCl formulation containing DCP was obtained for hydrophilic matrix tablets containing either lactose or DCP for the less water-soluble drug, zonisamide. In the case of the partially water-soluble drug, theophylline, formulated with lower molecular weight PEO 750, drug release increased considerably in the presence of both fillers with increasing storage time, however a stable release rate (similar to fresh samples) was observed in the case of higher molecular weight PEO 303 tablet matrices containing theophylline with either lactose or DCP. The hydration properties (e.g. solubility) of the diluents had a considerable effect on drug release behavior from various model matrices; this effect was dependent on both molecular weight of PEO and solubility of drug. PMID:25410967

Shojaee, Saeed; Kaialy, Waseem; Cumming, Kenneth Iain; Nokhodchi, Ali

2014-11-20

479

Preparation and evaluation of once-daily sustained-release coated tablets of tolterodine-L-tartrate.  

PubMed

In this study, once-daily, sustained-release matrix tablets of tolterodine l-tartrate (TOL) for treatment of overactive bladder (OAB) were prepared by direct compression using various amounts of hydrophilic polymers such as HPMC 2910 and HPMC 2208 along with other tablet excipients; the tablets were then coated. In vitro dissolution studies were carried out under different pH conditions. The dissolution data were fitted into zero-order, first-order, Higuchi and Korsemeyer-Peppas models to identify the pharmacokinetics and mechanism of drug release. Among the four formulations (F1-F4), the dissolution profiles of formulation F2 were most similar to the marketed product with similarity and difference factors of 70.25 and 1.59 respectively. Furthermore, pharmacokinetic studies were carried out in healthy human volunteers after oral administration of the prepared TOL sustained-release matrix-coated tablet and the marketed product. The results revealed that the pharmacokinetic parameters of AUC, Cmax, Tmax, t1/2, Kel, and MRT of TOL for the developed formulation (F2) were not significantly different from that for the marketed product, suggesting that they were bioequivalent. Therefore, the developed sustained-release tablet formulation of TOL could be an alternative dosage form to the SR capsule for treatment of OAB. PMID:24184032

Pradhan, Roshan; Kim, Yong-Il; Chang, Sun Woo; Kim, Jong Oh

2014-01-01

480

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

NASA Astrophysics Data System (ADS)

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.

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

2011-10-01

481

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

PubMed

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

Javadzadeh, Yousef; Musaalrezaei, Leila; Nokhodchi, Ali

2008-10-01

482

Hydroelastic analysis of a large floating structure  

Microsoft Academic Search

An analytical approach to predict the bending vibration of a very large floating structure of thin and elongated rectangular plate configuration, floating on water of shallow depth and under the action of a monochromatic head wave, is presented. The horizontal size of the plate is huge compared with the wavelength of the incident waves, yet the wavelength is much larger

M. Ohkusu; Y. Namba

2004-01-01

483

Future float zone development in industry  

NASA Technical Reports Server (NTRS)

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.

Sandfort, R. M.

1980-01-01

484

Oxygen and silver diffusion into float glass  

Microsoft Academic Search

In the float glass process, molten glass is floated on a molten metallic tin bath, such that tin penetrates the glass surface. Consequently, the glass has distinctly two different faces; the tin-penetrated face (bottom face) and the opposite face (top face). In this paper, the effects of tin on oxygen and silver diffusion into the top and bottom faces of

Satoshi Takeda

2006-01-01

485

Floating plant dominance as a stable state  

Microsoft Academic Search

Invasion by mats of free-floating plants is among the most important threats to the functioning and biodiversity of freshwater ecosystems ranging from temperate ponds and ditches to tropical lakes. Dark, anoxic conditions under thick floating-plant cover leave little opportunity for animal or plant life, and they can have large negative impacts on fisheries and navigation in tropical lakes. Here, we

Marten Scheffer; Sándor Szabó; Alessandra Gragnani; Egbert H. van Nes; Sergio Rinaldi; Nils Kautsky; Jon Norberg; Rudi M. M. Roijackers; Rob J. M. Franken

2003-01-01

486

IEEE Standard unifies arithmetic model Floating points  

E-print Network

years use IEEE floating-point arithmetic. This doesn't mean that they all get exactly the same resultsIEEE Standard unifies arithmetic model Floating points by Cleve Moler C l e v e ' s C o r n e r I f you look carefully at the definition of fundamental arithmetic operations like addition

Beron-Vera, Francisco Javier

487

Vertical pump with free floating check valve  

DOEpatents

A vertical pump with a bottom discharge having a free floating check valve isposed in the outlet plenum thereof. The free floating check valve comprises a spherical member with a hemispherical cage-like member attached thereto which is capable of allowing forward or reverse flow under appropriate conditions while preventing reverse flow under inappropriate conditions.

Lindsay, Malcolm (O'Hara Township, Allegheny County, PA)

1980-01-01

488

Pharmaceutical tablet compaction : product and process design  

E-print Network

This thesis explores how tablet performance is affected by microstructure, and how microstructure can be controlled by selection of excipients and compaction parameters. A systematic strategy for formulation and process ...

Pore, Mridula

2009-01-01

489

Tablets for Timely Design Documentation  

NSDL National Science Digital Library

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.

Brown, Cordelia

490

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

Code of Federal Regulations, 2014 CFR

...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...

2014-04-01

491

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

Code of Federal Regulations, 2012 CFR

...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:...

2012-04-01

492

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

Code of Federal Regulations, 2011 CFR

...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:...

2011-04-01

493

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

Code of Federal Regulations, 2013 CFR

...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...

2013-04-01

494

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

Code of Federal Regulations, 2011 CFR

...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...

2011-04-01

495

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

Code of Federal Regulations, 2010 CFR

...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...

2010-04-01

496

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

Code of Federal Regulations, 2013 CFR

...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:...

2013-04-01

497

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

Code of Federal Regulations, 2014 CFR

...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:...

2014-04-01

498

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

Code of Federal Regulations, 2012 CFR

...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...

2012-04-01

499

Three-dimensional data input by tablet  

Microsoft Academic Search

A large-area multiple-pen tablet system for three-dimensional data input is described. The large tablet area provides space for simultaneous use of several views of the three-dimensional object being digitized. The multiple pens enable the user to indicate a single point simultaneously in two such views, thus defining the three-dimensional position of the point. Five significant techniques are outlined. First, the

IVAN E. SUTHERLAND

1974-01-01

500

Mucoadhesive bilayer tablets of propranolol hydrochloride  

Microsoft Academic Search

The purpose of this research was to study mucoadhesive bilayer buccal tablets of propranolol hydrochloride using the bioadhesive\\u000a polymers sodium alginate (Na-alginate) and Carbopol 934P (CP) along with ethyl cellulose as an impermeable backing layer.\\u000a The tablets were evaluated for weight variation, thickness, hardness, friability, surface pH, mucoadhesive strength, swelling\\u000a index, in vitro drug release, ex vivo drug permeation, ex

Vishnu M. Patel; Bhupendra G. Prajapati; Harsha V. Patel; Karshanbhi M. Patel

2007-01-01