Quality control and methodology on rFC detection of bacterial endotoxins in zoledronic acid
Objective:To standardize the bacterial endotoxin testing criteria for zoledronic acid injection and estab-lish a detection method using recombinant factor C(rFC).Methods:The gel-clot method(BET)was utilized to test 13 batches of zoledronic acid injection from national supervision and random inspection.Interference tests were conducted on zoledronic acid injections from three manufacturers at different concentrations(500,100,50,25 μg·mL-1)using rFC test kits from two manufacturers.Results:Detection was performed for the specification of 100 mL∶5 mg and other specifications according to<0.50 EU per 1 mL and<5.0 EU per 1 mg,respectively,and all results met the criteria.The recovery rate for 25 μg·mL-1 using rFC kits from both manufacturers ranged between 50%and 200%.Validation of rFC.Methods:Eight batches of zoledronic acid injection were validated at 25 µg·mL-1,five batches of zoledronic acid injection(100 mL∶5 mg)were validated at 0.5 EU·mL-1,and all recovery rates were between 50%and 200%.Conclusion:The bacterial endotoxin testing method for zoledronic acid injection can be established as follows:for large volume injection products with 100 mL or more,each 1 mL should contain less than 0.50 EU of endotoxin(following the Chinese Pharmacopoeia 2020,general chapter 1143).For other specifications,each 1 mg of zoledronic acid should contain less than 10.0 EU of endotoxin.The rFC test kit method for bacterial endotoxins involved diluting the sample with water for bacterial endotoxin testing to contain 25 µg of zoledronic acid per 1 mL,or performing 1∶1 dilution for large volume injections(100 mL∶5.0 mg specifi-cation),with recovery rate between 50%and 200%as per the kit instructions.
zoledronic acid injectionbacterial endotoxingel-clot limitrecombinant factor Cstandardizationquality control