Natural rubber/gelatin composite capsule shell for controlling drug release

Abstract

The hydrophobicity of natural rubber (NR) film provides it with a potential material for preparation of controlled drug delivery systems. The purpose of this study was to develop the NR/gelatin composite capsule shells for controlled drug release. The NR film and the NR/gelatin composite films, at the NR: gelatin ratio of 3:7, 4:6, 5:5, 6:4 and 7:3, were prepared. It was found that the composite films possessed higher strength and modulus, but lower elongation than the NR film. The smooth NR film absorbed water/aqueous media only to a small extent and hence scarcely eroded. Incorporation of gelatin resulted in the rough films, which were capable of absorbing more water/aqueous media and, therefore, eroding more than the NR film. The capsule shells were subsequently prepared from the NR: gelatin ratio of 6:4 composite film, contributing to its good mechanical properties and minimal erosion. Propranolol HCl was filled into the developed capsule shells. The drug was gradually released and reached the maxima within 8 and 4 h, in pH 1.2 and 6.8 buffer solutions, respectively. Thus, the NR/gelatin composite capsule shells were successfully prepared and able to control the drug release efficiently.