Preparation of metronidazole microcapsules by coacervation-phase separation

Abstract

The metronidazole microencapsules were formulated by coacervation-phase separation. Starch and sodium alginate at different concentrations were swelled for 1.0 hour to serve as coating material. A mixture of alginate, starch, and metronidazole were injected without mixing into calcium chloride solutions (2 %, 4 %, 6 % w/t) via a nozzle needle with Ø = 0.7 in size at the flow rate of ca. 2mL/min. The distance between the needle head and the hardening solution was fixed at 6 cm. The prepared microencapsules were stored in the calcium chloride solution for 30 minutes, then cleaned by distilled water. The so forrmed  microencapsules were dried at 45-50^oC for 24 hrs. The resulted microencapsules were spherical with dry smooth surface and the drug release was extended up to 6 hours in the phosphate buffer 7.4.