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International journal of Pharmacy and Pharmaceutical Sciences, 2015
Objective: The attempt of the present study was to improve bioavailability and dissolution rate along with reduction in dosing frequency of Zidovudine from microspheres. Methods: In this study an effort was taken to devise and evaluate Zidovudine sustained release microspheres using different polymers such as Ethyl cellulose (EC), Eudragit RS100, Hydroxypropyl methylcellulose (Methocel K4M and Methocel K15M) by emulsion solvent evaporation method. UV-Spectrophotometric method was applied to calculate the drug content and in vitro dissolution studied according to USP paddle method were carried out in Phosphate Buffer (pH 7.4) for 8 hours. Scanning electron microscopic (SEM) technique was performed to obtain the particle size and morphological changes due to different polymers. Drug polymer compatibility studies were performed by Fourier Transform Infrared (FTIR) spectroscopy, Differential Scanning Calorimetry (DSC) and X-ray Powder Difftactometry (XRD). Results: The maximum and minimum releases of microspheres were observed 93.12% and 75.07% respectively after 8 hours. Drug entrapment efficiency for formulations varied from 56.21% to 94.14%. The release kinetics were studied in different mathematical release models following the zero order, first order, Higuchi, Hixson-Crowel and korsemeyer to find out the linear relationship and release rate of drug. In this experiment, it is difficult to explain the exact mechanism of drug release. The drug might be released by both diffusion and erosion as the correlation coefficient (R 2 Conclusion: In vitro study and different compatibility evaluation of Zidovudine from microspheres was showed that optimum release profiles may be obtained compared to pure drug.) best fitted with Korsemeyer model. No interaction between drug and polymers were observed from FTIR, DSC and XRD studies.
Formulation Development and Evaluation of Sustained Release Matrix Tablet of Zidovudine
American Journal of Advanced Drug Delivery, 2013
The objective of the research was firstly to investigate the behavior of Surelease (release retardant binder) alone and in combination with other hydrophilic polymers on the release of zidovudine from sustained release matrix tablet. Secondly, to compare between the release pattern of polyethylene oxide and Methocel K100M alone and in combination. A randomized surface methodology (RSM) was applied to study the effect of polymers on drug release. The independent variables of the formulation were: the type of polymers (X1), concentration of polymers (X2) in the tablet and dependent variables are the percentage drug release at 2 hours (Y1) and the percentage drug release at 12 hours (Y 2 ). Release kinetics were analyzed using zero-order, first order, higuchi's square root and korsmeyer-peppas empirical equations in terms of r 2 . Results of invitro drug release kinetics study suggests that, all formulations follows zero order kinetics with r 2 value in range of 0.99 and fitting the release data to korsmeyers equation release exponent n ranged from 0.83 to 1.22 and followed non-Fickian diffusion mechanism (anomalous transport) and super case II transport for Surelease formulations. Among all the formulations, F14 matrix tablet containing combination of Surelease and polyoxWSR301 shows 102.37% of drug release at the end of 12 hours.
PREPARATION AND IN-VITRO EVALUATION OF SUSTAINED RELEASE MATRIX TABLETS OF ZIDOVUDINE
Dogo Rangsang Research Journal, 2023
The sustained release matrix tablet used in this study contains eudragit and ethyl cellulose and was created using a direct compression technique. It also contains one grade of eudragit (RS100), three viscosity grades of HPMC (K100M, K15M, and K4M).Each of these manufactured tablets is examined for weight variation, friability, hardness, diameter, drug content, and drug release pattern. The study of drug-excipient interactions using FTIR Spectroscopy and ocular inspection (by keeping drug-excipient mixture for one month at room temperature). Comparative analyses of the dissolution profiles show that Non-Fickian diffusion or unusual drug release patterns are present in all formulations.
International Journal of Pharmacy and Pharmaceutical Sciences
Objective: The attempt of the present study was to improve bioavailability and dissolution rate along with reduction in dosing frequency of Zidovudine from microspheres. Methods: In this study an effort was taken to devise and evaluate Zidovudine sustained release microspheres using different polymers such as Ethyl cellulose (EC), Eudragit RS100, Hydroxypropyl methylcellulose (Methocel K4M and Methocel K15M) by emulsion solvent evaporation method. UV-Spectrophotometric method was applied to calculate the drug content and in vitro dissolution studied according to USP paddle method were carried out in Phosphate Buffer (pH 7.4) for 8 hours. Scanning electron microscopic (SEM) technique was performed to obtain the particle size and morphological changes due to different polymers. Drug polymer compatibility studies were performed by Fourier Transform Infrared (FTIR) spectroscopy, Differential Scanning Calorimetry (DSC) and X-ray Powder Difftactometry (XRD). Results: The maximum and minim...
International Journal of Pharmacy and Pharmaceutical Sciences, 2018
Objective: The current research was an attempt to formulate and design an extend release dosage form of zidovudine hydrochloride using various grades of ethyl cellulose (ethocel) such as ethocel 4CPS, ethocel 7 CPS and aqualon T10 Pharm EC with two grades of hydroxy propyl methyl cellulose (HPMC K4M and HPMC K15M). Methods: Pilot scale batches of nine formulations were prepared using kollidon and adopting wet granulation technique. Physiochemical properties of tablet and granules were examined prior compression to get tablet. Tablets were characterized as drug content, percentage weight variation, thickness, Hardness, percentage friability and in vitro drug release pattern and studied for 12 hour in USP Type-II apparatus using 900 ml Phosphate buffer at 37±0.5 °C. The dissolution release profile of drug in tablet was performed by various drug release kinetic modelling. Results: The result revealed formulation F8 containing ethocel 7CPS and aqualon T10 was able to delay the pure drug release for 12 h and followed Higuchi pattern. Whereas; formulations containing only ethocel 4CPS provided earlier drug release. Dissolution data of promising formulation were analysed with innovator formulation for similarity factor (f2), exhibited an acceptable value more than 50. FT-IR (fourier-transform infrared spectroscopy) and DSC (differential scanning calorimetry) study revealed no such incompatibility found between the pure drug and polymers but slight change in crystalinity were observed in XRD study (X-ray diffraction). SEM (scanning electron microscope) study revealed very rare intragranular pore and cavity. Conclusion: From that, it can be marked as viscosity and selection of ethocel have great importance in delay drug release.
International Journal of Pharmacy and Pharmaceutical Sciences, 2017
Objective: The purpose of this research work was to develop and evaluate microspheres appropriate for controlled release of zidovudine (AZT). Methods: The AZT loaded polylactide-co-glycolide (PLGA) microspheres were prepared by W/O/O double emulsion solvent diffusion method. Compatibility of drug and polymer was studied by Fourier-transform infrared spectroscopy (FTIR). The influence of formulation factors (drug: polymer ratio, stirring speed, the concentration of surfactant) on particle size encapsulation efficiency and in vitro release characteristics of the microspheres was investigated. Release kinetics was studied and stability study was performed as per ICH guidelines. Results: Scanning electron microscopy (SEM) images show good reproducibility of microspheres from different batches. The average particle size was in the range of 216-306 μm. The drug-loaded microspheres showed 74.42±5.08% entrapment efficiency. The cumulative percentage released in phosphate Buffer solution (PBS) buffer was found to be 55.32±5.89 to 74.42±5.08 %. The highest regressions (0.981) were obtained for zero order kinetics followed by Higuchi (0.968) and first order (0.803). Conclusion: Microsphere prepared by double emulsion solvent diffusion method was investigated and the results revealed that 216-306 μm microsphere was successfully encapsulated in a polymer. FT-IR analysis, entrapment efficiency and SEM Studies revealed the good reproducibility from batch to batch. The microspheres were of an appropriate size and suitable for oral administration. Thus the current investigation show promising results of PLGA microspheres as a matrix for drug delivery and merit for In vivo studies for scale up the technology.
Comparitive Studies of Hydrophilic Polymers on Sustained Drug Delivery of Zidovudine
2015
The goal in designing sustained or controlled delivery is to reduce frequency of dosing or to increase the effectiveness of the drug by localization at the site of action, reducing the dose required, providing uniform drug delivery. The terms Sustained release, prolonged release, modified release, extended release or depot formulations are used to identify drug delivery systems that are designed to achieve or extend therapeutic effect by continuously releasing medication over an extended period of time after administration of a single dose. [6] Considering the scope and availability of the natural polymers the present research work was planned with karaya gum, kondagogu gum and synthetic polymer HPMC(K100) as matrixing agents for the sustaining the drug release.
Formulation and Release Characteristics of Zidovudine-Loaded Solidified Lipid Microparticles
Tropical Journal of Pharmaceutical Research, 2014
Purpose: To formulate and determine the release profile of zidovudine (AZT)-loaded solidified lipid microparticles (SLMs). Methods: Different concentrations (0, 1, 2, 3 and 5 %w/w) of zidovudine (AZT) were formulated into microparticles in melt dispersion of Phospholipon ® 90H and goat fat in the ratio 1:1, 2:1, 2:3 and 1:3 followed by lyophilization. They were characterized for particle size, yield, entrapment efficiency (EE) and loading capacity (LC). In vitro release kinetics and mechanism of release were assessed sequentially in simulated gastric fluid (SGF, pH 1.2)and simulated intestinal fluid (SIF, pH 7.2). Results: The ratio 1: 1 formulation was the most stable in terms of physical observation.. Particle size analysis indicated that the particles were irregular in shape with size ranging from 5.10 ± 0.10 to 13.40 ± 2.20 µm. Yield decreased with increase in drug concentrations in the SLMs formulations. EE data showed that the microparticles containing 1 % w/w of AZT had the highest entrapment efficiency of 74.0 ± 0.03 %. LC also decreased with increase in concentration of AZT. AZT tablet released most of its content within 5 min with a sharp decrease in the concentration but the SLMs maintained its release for 8 to 12 h in different batches Conclusion: The results show that drug content has influence on drug release from the SLMs, but not on the mechanism of release. Furthermore, dose dumping was avoided and drug release mechanism was mostly non-Fickian while for the reference (commercial) tablet, it was Fickian.
International Journal of Drug Delivery, 2013
The aim of the research was to study the stability, release profile, pharmacokinetic and biodistribution properties of zidovudine (AZT)-solidified reverse micellar microparticulate. Lipid matrices formulated with Phospholipon ® 90H and goat fat at ratios of 1:1, 2:1, 3:1 and 2:3 were used to prepare AZT-loaded SLM by melt dispersion followed by lyophilization. In vitro release studies of the drug were carried out using a sequential drug release method in both SGF (pH 1.2) and SIF (pH 7.2) while the in vivo drug release studies were carried out using Wistar albino rats. The result of our findings showed that the drug is compatibility with the lipid matrix with the 1:1 showing the most stable microparticle preparation which was then optimized. The formulations showed a concentration dependent increase in their concentration maximum (C max) with values of 116.05 µg/ml, 124.21 µg/ml, 128.95 µg/ml, 138.95 µg/ml and time to reach maximum concentration (T max) values of 5h, 8 h, 8 h, and 5...
Oral Sustained Release Tablets of Zidovudine Using Binary Blends of Natural and Synthetic Polymers
Biological & Pharmaceutical Bulletin, 2010
Oral sustained release matrix tablets of zidovudine (ZDV) were prepared using different types, proportions and blends of carbopol 71G (C71) and a plant gum obtained from Abelmoschus esculentus (AEG). The effect of various formulation factors like polymer proportion, polymer type and pH of the dissolution medium on the in vitro release of the drug was studied, using the half change technique, in 900 ml of dissolution medium, at 100 rpm. Release kinetics were analyzed using Zero-order, Higuchi's square-root and Ritger-Peppas' empirical equations. In vitro release performance as revealed by the time taken for 70% of the drug to be released (t 70%), showed that the release rate decreased with increase in polymer proportion. Matrix tablets containing 10 and 20% AEG were found to exhibit immediate-release characteristics. Matrix tablets containing 30% AEG showed t 70% value of 204 min and extended the release up to 5 h, while matrix tablets containing 30% carbopol showed t 70% value of 234 min and extended the release up to 6 h. Three blends of AEG and C71 at the ratio of 1 : 2, 2 : 1 and 1 : 3 showed t 70% values of 132, 312 and 102 min respectively and extended the release up to 8 h. Mathematical analysis of the release kinetics indicated that the nature of drug release from the matrix tablets followed Fickian and anomalous release. Drug release from matrix tablets of zidovudine containing blends of AEG and C71 demonstrates the advantage of blending a natural and synthetic polymer over single polymer use.