Abstract
The formulation of a novel controlled release Parenteral dosage form was the goal of this study. Microbeads of crosslinked casein containing Diethyl-stilboestrol (DEST), as a model drug, have been prepared using emulsion polymerization technique. The effect of different concentrations of Glutaraldehyde, as a cross linking agent, on particle size, particle size distribution, shape of microbeads, drug content as well as the rate of drug release from the microbeads were studied. Spherical microbeads with low particle size distribution and high drug load were obtained as glutaraldehyde concentration increased. Furthermore, the release rate from the microbeads were decreasing with the increase of the concentration of the cross linking agent. The effect of pH of casein solution as well as the amount of added drug on the characteristics of the microbeads were also investigated. The biodegradability of casein microbeads prepared at glutaraldehyde concentration 2.37% were tested in α-chymotrypsin solution. The microbeads showed a distinct signs of biodegradation within few days of incubation. No signs of adverse effect were noticed when drug free casein microbeads were injected intraprotenially in mice. It was concluded that casein microbeads could be considered as a good candidate for the preparation of a dependable parenteral time release dosage form.