Objective:To explore the feasibility of gel-clot method for bacterial endotoxin test of denosumab injec-tion.Methods:Referring to general chapter 1143 in ChP 2020.Vol Ⅲ and Technical Report No.82 on Low Endotoxin Recovery published by PDA,bacterial endotoxin was detected by turbidimetric kinetic method and the endotoxin recovery of denosumab injection with different dilutions was calculated.Then based on the recovery,it was judged whether there was a LER issue and it was predicted how well the samples interfered the reaction between TAL reagent and bacterial endotoxin.Pre-experiment of gel-clot interference test was performed with TAL reagents of different sensitivity.The gel-clot interference test was performed for three batches of samples and the bacterial endotoxin was tested with TAL reagents from different manufacturers separately.Results:Denosumab injection had no LER issue,and whose high concentration had the interference on the reaction between TAL reagent and bacterial endotoxin.The interference of gel-clot TAL reagent having a sensitivity of not less than 0.25 EU·mL-1,was elim-inated by diluting the samples to 6 mg·mL-1 with BET water.Conclusion:The gel-clot method for the detection of bacterial endotoxin in denosumab injection is feasible and can be used as a routine quality control method.

Objective:To explore the feasibility of gel-clot method for bacterial endotoxin test of denosumab injec-tion.Methods:Referring to general chapter 1143 in ChP 2020.Vol Ⅲ and Technical Report No.82 on Low Endotoxin Recovery published by PDA,bacterial endotoxin was detected by turbidimetric kinetic method and the endotoxin recovery of denosumab injection with different dilutions was calculated.Then based on the recovery,it was judged whether there was a LER issue and it was predicted how well the samples interfered the reaction between TAL reagent and bacterial endotoxin.Pre-experiment of gel-clot interference test was performed with TAL reagents of different sensitivity.The gel-clot interference test was performed for three batches of samples and the bacterial endotoxin was tested with TAL reagents from different manufacturers separately.Results:Denosumab injection had no LER issue,and whose high concentration had the interference on the reaction between TAL reagent and bacterial endotoxin.The interference of gel-clot TAL reagent having a sensitivity of not less than 0.25 EU·mL-1,was elim-inated by diluting the samples to 6 mg·mL-1 with BET water.Conclusion:The gel-clot method for the detection of bacterial endotoxin in denosumab injection is feasible and can be used as a routine quality control method.

Objective:To establish a method for the determination of erythromycin in erythromycin enteric capsules. Methods:UV spectrophotometry was performed. Sodium hydroxide reacted with erythromycin to obtain a unsaturated ketone having maximum absor-bance at 235 nm. The content of erythromycin in erythromycin enteric capsules was determined by the UV absorbance of the unsaturat-ed ketone. Results: The linear range of erythromycin was 51. 18-307. 08 μg · ml-1 ( r =0. 999 9 ) and the average recovery was 99. 9%(RSD=1. 2%,n=6). Conclusion:The method is simple,accurate,sensitive and reproducible, which can be used for the de-termination of erythromycin in erythromycin enteric capsules.