Microencapsulation of soluble pharmaceuticals

Abstract

A method to microencapsulate water-soluble and liquid-paraffin insoluble drugs into spherical, discrete and free-flowing particles of ±175 μm size with excellent yield has been described taking diethylcarbamazine citrate as a model drug. In this method a gelatin-drug dispersion at 50°C is sprayed, using a simple apparatus designed in our laboratory, into chilled, dry liquid paraffin present in a china dish previously coated with a layer of hard paraffin and maintained at 5°C. After allowing the droplets to gel at 5°C for an hour, water was removed by freeze drying. Later liquid paraffin adhering to freeze-dried microcapsules was removed by washing with chilled, dry acetone. Various factors affecting the yield, size, shape and size distribution of microcapsules were optimized.