LEVEL A IN VITRO-IN-IVO CORRELATION DEVELOPMENT AND VALIDA- TION FOR TRAMADOL HYDROCHLORIDE FORMULATIONS

The objective of this article is to develop and validate the level A in vitro-in vivo correlation (IVIVC) for three different formulations of tramadol hydrochloride. The formulations included were Tramazac® (Ml, conventional tablet) and TRD CONTIN® (M2, sustained release tablet), and a new controlled release tablet prepared on the basis of osmotic technology (formulation IVB). To develop level A IVIVC, in vivo data were deconvoluted into absorption data by using Wagner-Nelson equation. The absorption data (percent drug absorbed) was plotted against percent drug dissolved keeping the former along x-axis and the later along y-axis. The highest determination coefficient (R² = 0.9278) of the level A IVIVC was observed for formulation MI, and then for M2 (R² = 0.9046) and IVB (R² = 0.8796). Additionally, plasma drug levels were approximated from in vitio dissolution data using convolution approach to calculate the prediction error (%), which was found to be < 10%.