Bioequivalence study of carbamazepine tablets: In vitro in vivo correlation

After the in vitro dissolution profiles of three Mexican carbamazepine products and the innovator product (Tegretol) in four different dissolution media: HCl 0.1 N, simulated gastric fluid, simulated intestinal fluid, and water containing 1% sodium lauryl sulfate (USP method) were assesed, their bioequivalence was evaluated in 12 healthy volunteers in a randomized crossover study. Single oral doses of 400 mg of each product were administered at intervals of 2 weeks. The products tested in this study showed significant differences in the peak concentration and the area under the curve (p < 0.05). A faster dissolution was observed when VSP method was used; however, no correlation was observed between the in vivo parameters and the in vitro dissolution results with this method. A linear relationship was found between the area under the curve and the percent dissolved at 45, 60 and 90 min when simulated intestinal fluid was used. (C) 1997 Elsevier Science B.V.