Evaluation of Pharmaceutical and Chemical Equivalence of Selected Brands of Diclofenac Sodium Tablets

Abstract

There is the need to subject different brands of the same drug to physicochemical tests to determine their pharmaceutical and chemical equivalence and the possibility of substituting brands and generics, while achieving the same therapeutic effect. Hence, this work was done to determine the variations in the properties of five brands of enteric coated slow release diclofenac sodium tablets. The brands were subjected to standard physicochemical tests. The results from the generics were compared to those of the innovator brand with reference to official standards. All the brands passed the chemical tests for drug content with a range of 98.1 to 100.76% w/w diclofenac sodium content. The innovator brand passed all the other tests, while the generics passed some tests but failed others. There were significant differences (p < 0.05) in the values obtained for uniformity of weight and friability tests for all the brands. No significant differences were observed for crushing strength and disintegration tests. The results showed that the brands are chemically but not physically equivalent. The generic brands could neither be substituted for each other nor for the innovator brand to achieve the same therapeutic effects.

Keywords: Tablet release properties, pharmaceutical equivalence, diclofenac

East and Central African Journal of Pharmaceutical Sciences Vol. 15 (2012) 3-9