Performance Evaluation of Marketed Brands of Sustained Release Diclofenac Sodium Tablets Using Statistical Approaches

Abstract

Six commercial brands of sustained release diclofenac sodium tablets have been comparatively studied for physical characteristics, hardness, uniformity of weight, assay and in vitro dissolution tests. Cumulative release greater than 85 % was obtained from all products tested within 8-12 h. Model fitting was done on release data using zero order, first order, Higuchi matrix and Peppas-Korsmeyer model. Some model independent parameters such as t25%, t50%, t90%, dissolution efficiency (DE 480 ) and mean dissolution time (MDT) were computed. Statistical tests such as repeated ANOVA, Friedman test, Friedman ANOVA, Kendall's coefficient of concordance and Tukey-Kramer multiple comparison tests were applied on the range of data obtained from different brands. The results indicated non-significant differences in physical parameters and in vitro drug release, but significant differences were found in hardness, weight variation and drug content. Further, only the second brand complied with theoretical release rate of 8.66 mg/h whereas other brands exhibited higher drug release rates. For all the brands, release was completed within 5-8 h. Keywords : performance evaluation, diclofenac sodium, physical and statistical tests, model dependent parameters, model independent parameters Ethiopian Pharmaceutical Journal Vol. 24 (2) 2006: pp. 91-97