Interference Elimination of Matrix Magnesium Sulfate on the Microbial Limit Test for Urea Cream / 中国药师

ABSTRACT

Objective:To eliminate the interference of matrix in urea cream on the microbial limit test. Methods: A certain a-mount of magnesium sulfate was added to the test solution followed by stirring and placing sometime to make the cream layering, and the water layer was used for the microbial limit detection. Results:After magnesium sulfate was added to urea cream, microbial limit test was not affected by the matrix. The average recovery of Escherichia oli, Staphylococcus aureus, Bacillus subtilis, Candida albicans and Aspergillus niger was 96. 00%, 97. 00%, 100. 00%, 99. 00% and 101. 00%, respectively. The negative and positive results of Psudomonas aeruginosa and Staphylococcus auress were reliable. Conclusion:In the detection of microbial limit for urea cream, mag-nesium sulfate can be used as a good auxiliary agent to make the detection method more convenient and reliable.