Preparation of metronidazole microcapsules for sustained delivery

ABSTRACT

Metronidazole is widely used in the treatment of both intestinal and extra-intestinal amebiasis. However, conventional administration usually shows unpleasant taste, nausea, epigastric distress and stomatitis. To avoid these unwanted side effects, a multiple-emulsification technique was used in the preparation of metronidazole microsphere using a mixture of ethyl cellulose [EC] and methyl cellulose [MC] as a matrix. Methyl cellulose was added to enhance drugs release from ethyl cellulose matrix, because the drug has a relatively long t 1/2 [about 16 to 12 hours]. Particles size analysis results showed that the extent of size distribution was reduced with enhancing the stirring rate and the microcapsule size was reduced as the emulsifier concentration was increased up to 2% w/w. This was the optimum concentration of the emulsifiers required for the multiple emulsification. The results, also, showed no correlation between the HLB of the used emulsifiers and the microcapsule size. The in vitro drug release was studied and prolonged release were obtained where 80-90% of metronidazole was released within 6-8 hours depending on drug polymer ratio. Further, an increase in the amount of water-soluble MC increased the drug released rate