Abstract: Objective：To establish the microbial limit test method for pharmaceutical excipients such as ferric black oxide， magnesium stearate and dextrin， and to carry out the applicability test of the method. Methods：The results were determined according to general rules 1105 and 1106 of the Chinese Pharmacopoeia(2020 edition).The total number of aerobic bacteria， molds and yeasts was checked by conventional plate method， and the control bacteria was checked by conventional method， 100mL tryptic soy peptone liquid medium. The recovery rate test was conducted for each experimental bacteria， and the applicability test was conducted for the control bacteria. Results：The total number of aerobic bacteria， fungi and yeasts of black ferric oxide， magnesium stearate and dextrin were all collected by conventional method， and the microbial recovery ratio was between 0.5 and 2.0. Escherichia coli was examined by conventional method， and the volume of pancreatic soy meal liquid medium was 100 mL. Conclusion：The established method can be used to detect the microbial limit of black ferric oxide， magnesium stearate and dextrin.

Key words: font-size:medium, ">Blackferric oxide；Magnesium stearate；Dextrin；Pharmaceutical excipient；Microbiological limit test