Sample records for ethocel
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Khan, Kamran Ahmad; Khan, Gul Majid; Zeeshan Danish, Muhammad; Akhlaq; Khan, Haroon; Rehman, Fazal; Mehsud, Saifullah
2015-12-30
Current study was aimed to develop 200mg controlled release matrix tablets of Losartan Potassium using Ethocel 100 Premium and Ethocel 100 FP Premium as rate controlling polymer. In-vitro studies were performed according to USP Method-I in phosphate buffer (PH 6.8) using pharma test dissolution apparatus. The temperature of the dissolution medium was kept constant at 37±0.5°C at 100rpm. Flow properties, physical quality control tests, effect of polymer size and drug-to-polymers ratios were studied using different kinetics models such as 1st-order, zero-order, Hixon Crowell model, Highuchi model and Power law. Difference factor f1 and similarity factor f2 were applied for dissolution profiles against Cardaktin® tablets used as a reference formulation. The matrices with polymer ethocel 100 FP Premiums have prolonged the drug release rate as compared to polymer ethocel 100 Premiums. The n values matrices with polymer ethocel grade 100 ranged from 0.603 to 0.857 indicating that the drug release occurred by anomalous non fickian diffusion kinetics while then value of reference Cardaktin® tablet was measured as 0.125 indicating that these tablets do not follow power law. The dissolution profiles of test formulations were different than that of reference Cardaktin®. This suggests the polymer Ethocel grade 100 can be proficiently incorporated in fabrication and development of once a day controlled release matrix tablets. Copyright © 2015. Published by Elsevier B.V.
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Characterization of ethyl cellulose polymer.
Mahnaj, Tazin; Ahmed, Salah U; Plakogiannis, Fotios M
2013-01-01
Ethyl cellulose (EC) polymer was characterized for its property before considering the interactions with the plasicizer. Ethocel Std.10 FP Premium from Dow chemical company USA was tested for its solubility, morphology and thermal properties. Seven percentage of EC solution in ethanol was found to be the right viscosity used to prepare the film. The EC polymer and EC film without any plasticizers showed almost identical thermal behavior, but in X-ray diffraction showed different arrangements of crystallites and amorphous region. Dynamic mechanical analysis of film showed that without a plasticizer, EC film was not flexible and had very low elongation with high applied force. The aim of the work was to avoid using the commercially available EC dispersions Surelease® and Aquacoat®; both already have additives on it. Instead, Ethocel EC polymer (powder) was characterized in our laboratory in order to find out the properties of polymer before considering the interactions of the polymer with various plasticizers.
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Mehta, R; Teckoe, J; Schoener, C; Workentine, S; Ferrizzi, D; Rajabi-Siahboomi, A
2016-12-01
Ethylcellulose is one of the most commonly used polymers to develop reservoir type extended release multiparticulate dosage forms. For multiparticulate extended release dosage forms, the drug release is typically governed by the properties of the barrier membrane coating. The ICH Pharmaceutical Development Guideline (ICH Q8) requires an understanding of the influence of critical material attributes and critical process parameters on the drug release of a pharmaceutical product. Using this understanding, it is possible to develop robust formulations with consistent drug release characteristics. Critical material attributes for ethylcellulose were evaluated, and polymer molecular weight variation (viscosity) was considered to be the most critical attribute that can impact drug release. To investigate the effect of viscosity variation within the manufacturer's specifications of ethylcellulose, extended release multiparticulate formulations of two model drugs, metoprolol tartrate and acetaminophen, were developed using ETHOCEL™ as the rate controlling polymer. Quality by Design (QbD) samples of ETHOCEL Std. 10, 20, and 100 Premium grades representing the low, medium, and high molecular weight (viscosity) material were organically coated onto drug layered multiparticulates to a 15% weight gain (WG). The drug release was found to be similar (f 2 > 50) for both metoprolol tartrate and acetaminophen multiparticulates at different coating weight gains of ethylcellulose, highlighting consistent and robust drug release performance. The use of ETHOCEL QbD samples also serves as a means to develop multiparticulate dosage formulations according to regulatory guidelines.
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Akhlaq, Muhammad; Khan, Gul Majid; Jan, Syed Umer; Wahab, Abdul; Hussain, Abid; Nawaz, Asif; Abdelkader, Hamdy
2014-11-01
Diclofenac sodium (DCL-Na) conventional oral tablets exhibit serious side effects when given for a longer period leading to noncompliance. Controlled release matrix tablets of diclofenac sodium were formulated using simple blending (F-1), solvent evaporation (F-2) and co-precipitation techniques (F-3). Ethocel® Standard 7 FP Premium Polymer (15%) was used as a release controlling agent. Drug release study was conducted in 7.4 pH phosphate buffer solutions as dissolution medium in vitro. Pharmacokinetic parameters were evaluated using albino rabbits. Solvent evaporation technique was found to be the best release controlling technique thereby prolonging the release rate up to 24 hours. Accelerated stability studies of the optimized test formulation (F-2) did not show any significant change (p<0.05) in the physicochemical characteristics and release rate when stored for six months. A simple and rapid method was developed for DCL-Na active moiety using HPLC-UV at 276nm. The optimized test tablets (F-2) significantly (p<0.05) exhibited peaks plasma concentration (cmax=237.66±1.98) and extended the peak time (tmax=4.63±0.24). Good in-vitro in vivo correlation was found (R(2)=0.9883) against drug absorption and drug release. The study showed that once-daily controlled release matrix tablets of DCL-Na were successfully developed using Ethocel® Standard 7 FP Premium.
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Dielectric Constant and Loss Data. Part 4
1980-12-01
Fluorinated ethers, Organic Chemicals Dept., P.R.-194Dow Chemical "Dowtherm" A, P.R.-194 T ORg C a p - Dew Corning Corp., IV-26, 27, 41, 42, "HVITON...Esso "Teresso" oil, V-78; P.R.-195 and MFl16, V-15 "Estawax", IV-57 "Eccosorb" MFll7, V-15, 242 Ethers, fluorinated , P.R.-194 Eggwhite. P.R.-202 "Ethocel...PPG, 8-20 Flourglas laminate, 9-33 "Gafite" cast polymer, IV-34 Fluorinated ethers, P.R.-194 Gasoline, aviation, 100 and 91 octane, Fluorcarbon
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Shah, Kifayat Ullah; Khan, Gul Majid
2012-01-01
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 f 2 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 C max, T max and AUC0-t were compared which showed an optimized C max and T max (P < 0.05). A good correlation was obtained between in vitro drug release and in vivo drug absorption with correlation value (R 2 = 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
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A Science-Based Understanding of Cermet Processing
DOE Office of Scientific and Technical Information (OSTI.GOV)
Cesarano, III, Joseph; Roach, Robert Allen; Kilgo, Alice C.
2006-04-01
This report is a summary of the work completed in FY01 for science-based characterization of the processes used to fabricate 1) cermet vias in source feedthrus using slurry and paste-filling techniques and 2) cermet powder for dry pressing. Common defects found in cermet vias were characterized based on the ability of subsequent processing techniques (isopressing and firing) to remove the defects. Non-aqueous spray drying and mist granulation techniques were explored as alternative methods of creating CND50, the powder commonly used for dry pressed parts. Compaction and flow characteristics of these techniques were analyzed and compared to standard dry-ball-milled CND50. Duemore » to processing changes, changes in microstructure can occur. A microstructure characterization technique was developed to numerically describe cermet microstructure. Machining and electrical properties of dry pressed parts were also analyzed and related to microstructure using this analytical technique.3 Executive SummaryThis report outlines accomplishments in the science-based understanding of cermet processing up to fiscal year 2002 for Sandia National Laboratories. The three main areas of work are centered on 1) increasing production yields of slurry-filled cermets, 2) evaluating the viability of high-solids-loading pastes for the same cermet components, and 3) optimizing cermet powder used in pressing processes (CND50). An additional development that was created as a result of the effort to fully understand the impacts of alternative processing techniques is the use of analytical methods to relate microstructure to physical properties. Recommendations are suggested at the end of this report. Summaries of these four efforts are as follows:1.Increase Production Yields of Slurry-Filled Cermet Vias Finalized slurry filling criteria were determined based on three designs of experiments where the following factors were analyzed: vacuum time, solids loading, pressure drop across the filter paper, slurry injection rate, via prewetting, slurry injection angle, filter paper prewetting, and slurry mixing time. Many of these factors did not have an influence on defect formation. In order of decreasing importance, critical factors for defect formation by slurry filling are vacuum time (20 sec. optimal), slurry solids loading (20.0 g of cermet with 13.00 g of DGBEA solvent (21.2 vol%)), filling with the pipette in a vertical position, and faster injection rates (%7E765 l/s) as preferable to slower. No further recommendations for improvement to this process can be suggested. All findings of the slurry filling process have been transferred to CeramTec, the supplier. Paste filling methods appear to show more promise of increasing production yields. The types of flaws commonly found in slurry-filled vias were identified and followed throughout the entire source feedthru process. In general, all sizes of cracks healed during isopressing and firing steps. Additionally, small to medium sized voids (less than 1/3 the via diameter) can be healed. Porosity will usually lead to via necking, which may cause the part to be out of specification. Large voids (greater 4 than 1/3 of the diameter) and partial fills are not healed or produce significant necking. 2.Viability of High-Solids-Loading-Cermet Paste for Filling Source Feedthru ViaThe paste-filling process is easy to implement and easier to use. The high solids loading (>40 vol %) reduces the incidence of drying defects, which are seen in slurry filled (%7E23 vol %) vias. Additionally, the way in which the vias are filled (the paste is pushed from entrance to exit, displacing air as the paste front progresses), reduces the chance of entrapped voids, which are common in the slurry filling process. From the fair number of samples already filled, the likelihood of this process being a viable and reliable process is very good. Issues of concern for the paste process, as with any new process, are any problems that may arise in subsequent manufacturing stages of the neutron tube that may be affected by subtle changes in microstructure. Both MC4277 and MC4300-type source feedthrus were paste-filled by hand. X-ray analysis showed a much lower existence of voids in the green parts as compared to slurry-filled parts. The paste shows improvements in shelf life (weeks) as compared to slurry (minutes). This method of introducing the cermet to the via also lends itself very well to an automated filling process where a machine can either drill vias or, with the aid of a vision system, find pre-drilled vias and fill them with paste. The pastes used in this work prove the concept of this automated filling process as MC4277 sources have been filled using such a prototype machine, however, better performing pastes can be developed which are less hazardous (aqueous systems). The paste process was also used to successfully fill MC4300 "dogleg" type sources.3.Optimize CND50 Two methods of creating granulated cermet powder for comparison with dry-ball milled CND50 were explored. The first method, non-aqueous spray drying, was performed at Niro Inc. used a 40/60 (wt %) ethanol/toluene solvent and three binder systems; polyvinyl butyral (B79), ethylcellulose (Ethocel), and hydroxypropylcellulose (Klucel). Due to the nature of small spray-dry systems, an excess amount of fines was present in the granulated powder, which may have contributed to the low angles of repose (68 to 78). This is a moderate increase in 5 flowability as standard dry-ball milled powder possesses an angle of repose of 79-89. Mist granulated powders were produced with a tert-butanol solvent and polyvinyl butyral binder system. The angles of repose were more promising (28). More investigation into the mist granulation method is required. Also, aqueous spray drying may be possible with cermet and should be explored. Compaction of all granulated powders is much closer to a proven pressing powder (Sandi94 - angle of repose 29) which should allow cermet to be pressed to near net shape where die filling is difficult for non-flowing powders.4.Microstructure Characterization An analytical technique was developed to numerically characterize microstructures in terms of molybdenum dispersion, homogeneity, and percolation indices. This technique was applied to dry-ball-milled samples of various ball-milling times (0.5 to 20 hours). Significant change in the microstructure could be seen with milling time. Increased milling time caused agglomeration of molybdenum particles, increasing the percolation index, whereas short milling times promoted higher dispersion indices. This phenomenon is contrary to conventional understanding of mixing. However, conventional ball milling does not usually incorporate granules with binder and separate particles. This discrepancy may explain the odd mixing behavior. It is important to note that the high percolation index possessed by long ball mill times showed lower electrical resistance than low-percolation-index microstructures. However, machinability of high percolation, low-dispersion-index microstructures were poor as compared to microstructures with high dispersion indices and moderate percolation indices. This trade-off between dispersion and percolation (at constant molybdenum levels) suggests that microstructures can be achieved that posses good mechanical and electrical properties. Coincidentally, microstructures that satisfy this condition are produced by the standard dry-ball-milled CND50 (4 hour ball mill time). The performance and sensitivity of the microstructure characterization technique should be evaluated, specifically for electrical conductivity. Processing techniques to decrease the percolation index (lowering molybdenum content, excess ball milling, 6 larger molybdenum particles, etc.) should be employed to determine the point where cermet is not conductive or falls below electrical conduction specifications.7« less