Application of interpolymer complexation of polyvinylpyrrolidone/carboxyvinyl polymer to control of drug release.

Abstract

Interpolymer complex formation of polyvinylpyrrolidone (PVP) with carboxyvinyl polymer (CP) was examined by turbidity measurement, a binding isotherm study and Fourier-transform infrared spectroscopy. The interpolymer complex of PVP with CP was found to be formed in the unit molecular ratio of 1 : 1 under ideal conditions, though the ratio of PVP in the solid complex was lower than 1 : 1 under practical conditions. Hydrogen bonding might be the driving force for the complexation, and the degree of hydrogen bonding was calculated to be about 40 to 50%.The slowest dissolution rate of chlorpheniramine maleate from tablets, which consisted of a blend of PVP and CP was observed when the polymer combination ratio was 1 : 1. In the case of indomethacin, the longest lag time for the dissolution was observed at the polymer ratio of 1 : 1. Therefore, the drug dissolution behavior from PVP/CP tablets is dependent on the complex formation of PVP and CP.