Absorption Studies Using Inverted Intestine Segment: A Tool for Estimation of Dissolution-Absorption Correlation of a Controlled Release Formulation

Abstract:

The objectives of the study was to design a laboratory in vitro approach to investigate the dissolution-absorption relation of the selected drug Atenolol, formulated as delayed release tablet dosage form. The proposed in vitro continuous dissolution-absorption system consisted of dissolution apparatus with tissue holding assembly placed at the side. The study was performed for 4 h. Quantitative match for the drug dissolution and absorption through the intestinal wall was not observed. To predict a dissolution-absorption relationship for Atenolol, fraction absorbed (F ) in receptor compartment was plotted against fraction dissolved (F_a ) in donor compartment. This plot indicates that absorption is a d permeation-rate limited. The ratio of permeation rate constant to dissolution rate constant denoted by á was found to be 0.668 which indicates the permeation-rate-limited absorption of Atenolol and is in agreement with the biopharmaceutical classification of the Atenolol. The proposed model also can be used as a tool for biopharmaceutical classification of drugs, and for characterization of the prototype formulations.

KEYWORDS: Inverted intestinal segment, Permeation, Continuous dissolution- absorption, Permeation-absorption.