Investigation of tablettability and drug release properties of ethyl cellulose (original) (raw)
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The Scientific World Journal, 2012
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 AUC 0-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.
Evaluation of ethylcellulose as matrices for controlled release drug delivery
Pakistan journal of pharmaceutical sciences, 2005
As the efficiency of a matrix forming polymer in sustaining drug release is a multiple function of physico-chemical nature of the active ingredient and pH of the surrounding environment, the study was undertaken to evaluate the effect of pH of dissolution media on the release profile of three drug molecules with diversified physico-chemical properties. Matrix tablets of diclofenac sodium, theophylline and diltiazem HCl were prepared using ethylcellulose as the matrix forming agent. The drug dissolution behavior of the matrix tablets were studied over 10 hours in buffer media of pH 1.2, 4.5 and 6.8. Elevation of pH of the dissolution medium increased the rate and extent of diclofenac release. However, for diltiazem HCl, increasing the pH showed the reverse pattern. Theophylline release, on the other hand, seemed to be unaffected by the pH of the dissolution media. This can be correlated with the physico-chemical characteristics of the drugs. Effect of compression force on drug releas...
International Journal of Applied and Basic Medical Research, 2013
Aim: The current paper was an attempt to design a sustained release dosage form using various grades of hydrophilic polymers, Hypromellose (hydroxyl-propyl methylcellulose [HPMC] K15M, HPMC K100M and HPMC K200M) and Polyacrylate polymers, Eudragit RL100 and Eudragit RS100 with or without incorporating ethyl cellulose on a matrix-controlled drug delivery system of Metformin hydrochloride. Materials and Methods: Laboratory scale batches of nine tablet formulations were prepared by wet granulation technique (Low shear). Micromeritic properties of the granules were evaluated prior to compression. Tablets were characterized as crushing strength, friability, weight variation, thickness, drug content or assay and evaluated for in-vitro release pattern for 12 h using Phosphate buffer of pH 6.8 at 37 ± 0.5°C. The in-vitro release mechanism was evaluated by kinetic modeling. Results and Discussion: The results obtained revealed that HPMC K200M at a concentration of 26% in formulation (F6) was able to sustain the drug release for 12 h and followed the Higuchi pattern quasi-Fickian diffusion. With that, combined effect of HPMC K15M as an extragranular section and Eudragit RS100 displayed a significant role in drug release. Dissolution data were compared with innovator for similarity factor (f2), and exhibited an acceptable value of ≥50 Three production validation scale batches were designed based on lab scale best batch and charged for stability testing, parameters were within the limit of acceptance. There was no chemical interaction found between the drug and excipients during Fourier Transform Infrared Spectroscopy (FTIR) and Differential scanning calorimetry study. Conclusion: Hence, combinely HPMC K200M and Eudragit RS100 at a suitable concentration can effectively be used to sustain drug release.
Ethylcellulose matrix controlled release tablets of a water-soluble drug
International Journal of Pharmaceutics, 1995
Pseudoephedrine hydrochloride was used as a model drug to prepare direct compression sustained release tablets with ethylcellulose (EC). Initially, different viscosity grades of EC were studied. An increase in viscosity grade resulted in a marginal to moderate increase in the release rate. However, lower viscosity grades produced harder tablets. The highly compressible 10 cp grade was used to study the effect of drug loading, particle size, compression force, and magnesium stearate concentration on release properties. The rate of drug release decreased with a decrease in the drug concentration in the matrix. Except for tablets prepared with EC having a particle size fraction 250-420 and 177-250/xm, drug release up to 80% exhibited a square root of time dependency and tablets remained intact during dissolution. Tablets prepared with either the EC 250-420 or 177-250 Izm particle size fraction eroded. The square of the release rate is proportional to drug concentration in the matrix, indicating that the release of pseudoephedrine hydrochloride from EC matrices is primarily matrix-controlled.
Dhaka University Journal of Pharmaceutical Sciences, 2012
The objective of the present study was to develop a once-daily sustained release matrix tablet of Aceclofenac using hydroxypropyl methyl cellulose (Methocel K 100M CR) as release controlling factor and to evaluate drug release parameters as per various release kinetic models. The tablets were prepared by direct compression method. The powder blends were evaluated for angle of repose, loose bulk density, tapped bulk density, compressibility index, total porosity and drug content etc. The tablets were subjected to thickness, weight variation test, drug content, hardness, friability and in vitro release studies. The in vitro dissolution study was carried out for 24 hours using United States Pharmacopoeia (USP) 22 paddle-type dissolution apparatus in phosphate buffer (pH 7.4). The powder blends showed satisfactory flow properties, compressibility index and drug content etc. All the tablet formulations showed acceptable pharmacotechnical properties and complied with pharmacopoeial specifications. The results of dissolution studies indicated that the formulation F-3 (40% Methocel K100M CR of total weight of tablet) could extend the drug release up to 24 hours and the total release pattern was very close to the theoretical release profile. By comparing the dissolution profiles with the originator brand of Arrestin SR, the formulation F-3 exhibited drug release profile like originator brand. From this study, a decrease in release kinetics of the drug was observed by increasing the polymer concentration. Kinetic modeling of in vitro dissolution profiles revealed the drug release mechanism ranges from diffusion controlled or Fickian transport to anomalous type or non-Fickian transport, which was only dependent on the type and amount of polymer used. The drug release followed both diffusion and erosion mechanism in all cases. The drug release from the formulation (F-3) was satisfactory after 3 months storage in 40 0 C and 75% RH. Besides, this study explored both of the optimum concentration and effect of polymer(s) on Aceclofenac release pattern from the tablet matrix for 24 hour period. The matrix tablet of Aceclofenac using HPMC with molecular weight of K100M controlled the drug release effectively for 24 hours; hence the formulation can be considered as a once daily sustained release tablet of Aceclofenac in order to improve patient compliance.
Model drug release from matrix tablets composed of HPMC with different substituent heterogeneity
International Journal of Pharmaceutics, 2010
The release of a model drug substance, methylparaben, was studied in matrix tablets composed of hydroxypropyl methylcellulose (HPMC) batches of the USP 2208 grade that had different chemical compositions. It was found that chemically heterogeneous HPMC batches with longer sections of low substituted regions and lower hydroxypropoxy content facilitated the formation of reversible gel structures at a temperature as low as 37 • C. Most importantly, these structures were shown to affect the release of the drug from matrix tablets, where the drug release decreased with increased heterogeneity and a difference in T80 values of 7 h was observed between the compositions. This could be explained by the much lower erosion rate of the heterogeneous HPMC batches, which decreased the drug release rate and also released the drug with a more diffusion based release mechanism compared to the less heterogeneous batches. It can therefore be concluded that the drug release from matrix tablets is very sensitive to variations in the chemical heterogeneity of HPMC.
The specific aim of this study was to prepare sustained release matrix tablets containing indapamide as a low dose and low water solubility model drug. The matrix formers were composed of blends of hydroxypropyl methylcellulose as a swellable polymer and methyl cellulose as an erodible polymer. The matrix tablets were prepared by the direct compression technique and they have shown robust and acceptable physical properties with a content uniformity within the acceptable limits. Lactose and microcrystalline cellulose were investigated as additives to these matrices in order to adjust and modulate the release of the drug from the matrices to achieve a release profile similar to that obtained from the reference commercial product, Natrilix ® . All matrix tablets prepared with these two additives have gave a release profile that is close to zero order kinetics, however, the matrix tablets prepared with lactose gave a release profile with closer resemblance to that of the reference product with a similarity factor (F2) of 86. This is attributed to the rapid water solubility of lactose which enhanced higher erosion of the tablets, and thus, higher dissolution and diffusion of the drug. Microcrystalline cellulose is a swellable polymer where it has resulted in delayed release of the drug with time as compared to the reference product. Investigation of the mechanism of release of the drug from the matrices indicated that erosion is the dominant mechanism of drug release from these matrices.
European Journal of Pharmaceutical Sciences, 1999
In the present work, the drug volume fraction profiles of a colored and very soluble drug, buflomedil pyridoxal phosphate, in the gel layer of initially glassy hydroxypropylmethyl cellulose matrices were studied, using image analysis of pictures of the matrices during swelling and release. The goal was to correlate the drug release kinetics with the dynamic behavior of the drug gradient in the gel layer. An inert (nonswellable) matrix, manufactured by substituting hydroxypropylmethyl cellulose with an inert polymer and containing the same amount of buflomedil pyridoxal phosphate, was prepared as well. The drug color gradient in the partially extracted region and the flux of this matrix were compared to the swellable matrix. The drug gradient in the dissolved drug gel layer of swellable matrices was observed. It was demonstrated that drug release kinetics does not only depend on drug diffusion and matrix erosion, but also on drug dissolution in the gel and on polymer relaxation.