RECENT APPROACHES OF SOLID DISPERSION: A NEW CONCEPT TOWARD ORAL BIOAVAILABILITY .

 Solid dispersion (SD) has been a major advanced technology in overcoming dissolution and bioavailability problem of poorly soluble compounds. Formulation of SD in water-soluble carrier has becoming more researched over the past four decades for solubility and relative bioavailability enhancement. By reduction of the size of the drug particle to the minimum level which will enhance drug wettability and ultimately bioavailability will be definitely improved. This review article elaborates recent advanced technology and characterization of SDs and also discusses the problems and their solution for the development of better formulations

PREPARATION, CHARACTERIZATION AND STABILITY STUDIES OF SOLID SELF EMULSIFYING DRUG DELIVERY SYSTEM OF NIFEDIPINE

Objective: The objective of this work was to improve the solubility and dissolution rate of Nifedipine by preparing a solid-self micro emulsifying drug delivery system (Solid-smedds). Methods: Liquid-self-emulsifying drug delivery system formulations were prepared by using linseed oil as oil, tween 80 as a surfactant and PEG 400 as cosurfactant. Components were selected by solubility screening studies and the self-emulsifying region was identified by the pseudo-ternary phase diagram. Thermodynamic stability study was performed for the determination of stable liquid-smedds formulation. These formulations were evaluated for self-emulsification time, drug content analysis, robustness to dilution test, particle size analysis, in vitro diffusion study, and Stability study. Solid self-micro emulsifying formulations were prepared by using aerosil-200 at a different ratio. Lf9S (0.65:1) was selected due to its highest drug entrapment efficiency and a decrease in particle size. It was selected for further studies into DSC, SEM, FTIR, and XRD analysis. Results: DSC and XRD result shows that the drug within the formulation was in the amorphous state. From the SEM study, it was observed that the drug has been uniformly distributed and having a smooth surface. From the in vitro dissolution study, it improved the dissolution rate of nifedipine which was 98.70% of drug release where pure drug release only 6.72%. Conclusion: In conclusion, a solid self-micro emulsifying drug delivery system is improved the solubility and drug release rate but also improved the stability of the formulation

APPLICATION OF CENTRAL COMPOSITE DESIGN FOR OPTIMIZATION OF EFFERVESCENT FLOATING TABLETS USING HYDROPHILIC POLYMERS

The aim of the present study was to optimize effervescent floating tablets of Cefixime Trihydrate as model drug by optimization of polymers concentration using central composite design. Mean dissolution time (MDT), time required to release 50% of drug (t50%), drug release at 2 h (R2h) and dissolution efficiency in 2 h (DE2h) were taken as target responses, where as the quantity of different polymers such as Carbopol 934P (viscoelastic agent), Sod.CMC (swelling agent) were considered as independent variables. A second-order polynomial equation was determined by the multiple regression analysis of the experimental data. The best fitting model was selected based on the comparisons of the coefficient of determination (r2), adjusted coefficient of determination (adj. r2). In addition, analysis of variance (ANOVA) was used to evaluate the statistical significance of the quadratic polynomial model. The optimum values for the critical components were obtained as 13.151% Carbopol 934P and 4.08% of Sod.CMC with predicted value of 4.926 h MDT, 5.257 h t50%, 27.6316% R2h and 16.5951% DE2h from desirability and overlay plot. Further the reliability of the model was checked by validating the observed responses from optimized formula. The drug release from characteristics of all formulations followed Higuchi model with a non-Fickian diffusion mechanism. Further the data of FTIR study showed there was no interaction of drug and excipients used for the preparation of floating tablets.                                      Key words: Central composite design, Cefixime Trihydrate, Mean dissolution time, Fickian diffusion, dissolution efficienc