The microencapsules of glipizide were made by coacervation-phase separation. The suspension consisting of sodium alginate as coating material, glipizide as core material and Aerosil were prepared by constant agitation with a magnetic mixer at 400-600 rpm for 1.0 hours. The resulting suspension was injected into 10.0 percent calcium chloride solution by peristaltic pump system, via a nozzle needle of size 25. The prepared microcapsules were cured in the calcium chloride solution for 60 minutes, then dried at room temperature for 12 hours, followed by drying at 50°C for 3-4 hours. The resulted microcapsules were spherical with a smooth surface, and the drug release was up to 7 hours.