Biopharmaceutical characterization of carbamazepine immediate release tablets. In vitro-in vivo comparison.

A growing concern for the biopharmaceutical characterization of pharmaceutical products increased the interest in the evaluation and identification of physicochemical properties of drugs and dosage forms that govern its biological performance. In vitro and in vivo characteristics of two carbamazepine (CAS 298-46-4) immediate release tablets were investigated and compared in order to establish level A in vitro-in vivo correlation. An in vivo study was conducted as a controlled, two-way, complete cross-over, single dose, pharmacokinetic trial in 18 subjects. The in vitro study was performed using various dissolution media in order to evaluate their potential influence on drug release and distinguish the set of experimental conditions relevant to the in vivo behavior of the investigated drug products. Beside significant differences among in vitro release profiles, the in vivo data indicated bioequivalence of the two formulations. Although a high level of correlation between in vivo and in vitro data was observed in some media, there was no single in vitro-in vivo correlation model applicable to both investigated products. The obtained results add to the existing debate on the rationale for the use of surfactants in drug release media and their in vivo relevance, emphasizing the importance of in vitro dissolution testing in addition to in vivo bioequivalence testing.