Comparative In-vitro Evaluation Of Branded Generics And Innovator Brand Of Carbamazepine Tablets

Abstract

Background: Carbamazepine, a widely used antiepileptic drug is marketed both as branded and generic product. Loss of seizure  control on switching from one brand to another has been reported.
Objective: The objective of this study was to compare the dissolution profiles of the branded generic products with the innovator brand and evaluating their compliance with other official specifications.
Methods: Four brands of 200 mg carbamazepine immediate release tablets (A,B,C and D) were purchased from pharmacies in Lagos and were characterized with respect to shape, uniformity of weight, friability, hardness, moisture content, disintegration and assay of active ingredient. Dissolution studies were also carried out to evaluate percentage drug release and dissolution profiles to assess compl iance with United States Pharmacopoeia (USP) specifications using three media.
Results: Physical parameters: uniformity of weight, assay of active ingredient, moisture content, friability, and hardness, were within specifications for all products. Brand D did not meet the disintegration test specifications. Result of assay was: A 103.5%, B 106.0%, C 106.8% and D 100.5%. The dissolution profiles of all products were similar to that of the innovator except for D which had f values indicating 2 difference in 1% sodium lauryl sulphate (SLS) and phosphate buffer.
Conclusion: Products B and C may be interchanged with innovator brand (Product A) but product D should not because of the f value. In vivo evaluations of 2 products will be required to determine their complete bioequivalence picture to ensure efficacy on product
switch.

Key words: Carbamazepine; dissolution profile; f ; 2 antiepileptic