Goodness of Fit Model Dependent Approaches of Controlled Release Matrix Tablets of Zidovudine

Objectives: The objective of the study was to develop controlled release matrix tablet of zidovudine and to understand the release kinetics of drug by applying several mathematical model dependant and independent approaches. Various equations and models are developed for evaluating the drug release. Comparison of original and predicted release profile was most common way for selection of optimum formulation. Methods: In this study drug release profiles are characterized by using several parameters like percentage of drug released at 1 h and 12 h (R1h , R12h ), dissolution efficiency at 2 h and 12 h (DE2h , DE12h ) and pair wise procedures such as similarity factor (f1 ), difference factor (f2 ) and rescigno indices (ξ1 , ξ2 ) for getting the optimum formulation. Six batches (C1 to C6) of different concentration of carbopol embedded controlled release matrix tablets of Zidovudine were evaluated. Further the criteria for selection of appropriate model was based on goodness of fit (R2, adj-R2), sum square residual (SSR), F value and Akaike Information Criterion (AIC). Results & Conclusion: Formulation C5 showed highest values of DE2h , DE12h (19.45%, 57.63%) with acceptance criteria of f2 (51.63), f1 (9.91), ξ1 (0.063) and ξ2 (0.066). Further, drug release from optimum batch C5 was explained by the Higuchi model, due to highest value of R2 (0.992), adj-R2 (0.991) with lowest value of SSR (62.22), F (5.65) and AIC (53.56) data. Moreover a simple mathematical equation was applied to determine the deviation of area under curve (AUC) between predicted and observed dissolution data. On an average of 13.4% percent deviation of AUC was observed in optimum batch.