Preparation of microcapsules from complex coacervation of Gantrez-gelatin. II. In vitro dissolution of nitrofurantoin microcapsules.

Nitrofurantoin crystals were encapsulated in a Gantrez-gelatin complex coacervation system. The encapsulation process was reproducible and inexpensive and the microcapsules were free flowing and directly compressible into tablets. In vitro release of nitrofurantoin from Gantrez-gelatin microcapsules was studied as a function of the core:coat ratio, the molecular weight of Gantrez and the particle size of the microcapsules. The release of the drug was significantly reduced using G149-gelatin microcapsules of core:coat ratio of 1:2. Release data were examined kinetically and were found to follow a diffusion-controlled model. In vitro release of the drug from the microcapsules filled in capsules and compressed into tablets confirmed the efficiency of the encapsulation process for preparing prolonged release formulations.