Matrix polymeric excipients: comparing a novel interpolyelectrolyte complex with hydroxypropylmethylcellulose.

The in vitro dissolution, swelling, and erosion behavior of monolithic matrix systems containing the well-known hydrophilic polymer, hydroxypropylmethylcellulose, and a combination of chitosan and polycarbophil in the form of an interpolyelectrolyte complex were compared in this study. The two different types of matrix systems showed both a combination of swelling and erosion as the drug release mechanism. Kinetic analysis of the in vitro release profiles of water-soluble drugs from the matrix tablets illustrated that those containing the chitosan-polycarbophil complex exhibited higher mean dissolution time values and therefore slower drug release compared with the other matrix systems. The analysis also indicated that zero-order release kinetics were approached for some of the formulations containing the chitosan-polycarbophil complex, while this could not be achieved for those containing hydroxypropylmethylcellulose.