Preparation technology and in-vitro release characteristics of metronidazole-loaded carboxymethyl chitosan sustained-release microspheres

Key words: 
• metronidazole /
• carboxymethyl chitosan /
• microsphere /
• in vitro release

Abstract: Objective: To study the optimum technology for preparing metronidazole-loaded carboxymethyl chitosan（MZ-CMC） microspheres by emulsification and cross-linking process and to investigate the in-vitro release characteristics of MZ-CMC microspheres. Methods: An orthogonal test,based on 4 factors including CMC concentration,MZ/CMC（W/W）,glutaradehyde/CMC（W/W） and agitation speed,was employed to determine the optimum preparetion technology of microspheres.The in vitro release behavior was recorded and evaluated. Results: For this 4 factors,the degree of influence on the quality of microspheres were gradually lower in the sequence of "agitation speed","MZ/CMC（W/W）","glutaradehyde/CMC（W/W）",and "CMC concentration".Prepared with optimized method in this test,the proportion of microspheres with diameter from 50-200 μm was 48.86%.The drug content was 48.19%,and the enveloping rate was 37.46%.The in virto release time was from 6-8 h in 3 types of buffer solution of pH1.2,6.8 and 7.6. Conclusion: The preparing technology for MZ-CMC microspheres used in this test is dependable,and the in vitro release of MZ from the microspheres is sustained.