Abstract: Objective To establish a detection method for bacterial endotoxin in trimethyl-phloroglucinol. Methods According to the General Requirements of the Chinese Pharmacopoeia(2020 Edition),three methods were adopted to establish one for detection of bacterial endotoxin.①The test sample was dissolved in dimethyl sulfoxide(DMSO) to a concentration of 10 mg·mL^-1, diluted 200-fold with BET water, and tested using the gel method with Limulus amebocyte lysate at a sensitivity of 0.03 EU·mL^-1.②The test sample was dissolved in 70% ethanol to a concentration of 5 mg·mL^-1, diluted 30-fold with BET water, and tested using the gel method with Limulus amebocyte lysate at a sensitivity of 0.25 EU·mL^-1. ③The test sample was dissolved in methanol to a concentration of 100 mg·mL^-1. The test solution was diluted to 10 mg·mL^-1 with 20% Tween 80 solution before being diluted 40-fold with BET water and tested using the gel method with Limulus amebocyte lysate at a sensitivity of 0.03 EU·mL^-1. Results After the tested products were dissolved with the three methods, the interference of the solvent and test sample with endotoxin detection was eliminated. The results of the interference test met the requirements. Conclusion Three test methods for bacterial endotoxin in trimethyl-phloroglucinol have been established, which can provide a reference for the establishment of detection methods for bacterial endotoxin in insolvable samples.

Key words: Trimethyl-Phloroglucinol, Pharmaceutical Excipients, Bacterial Endotoxin, Gel Method, Dimethyl Sulfoxide, Insolubility