An in vitro/in vivo correlation for the disintegration and onset of drug release from enteric-coated pellets.

An empirical mass-transfer model for enteric-coating dissolution that uses in vivo dissolution data to characterize the pH-dependent solubility properties of the polymer film and a mass-transfer coefficient determined from in vivo dissolution or disintegration studies is developed. Once the in vivo mass-transfer coefficient has been evaluated, it can be used in conjunction with in vitro dissolution data from other formulations to predict the in vivo time to disintegration and onset of drug release. Results of in vitro dissolution experiments using the USP basket dissolution apparatus and in vivo disintegration experiments using gamma scintigraphy with four enteric-coated pellet formulations are presented. The good agreement among the in vivo mass-transfer coefficients that were determined supports the validity of the model.