Development of bacterial endotoxin standard for insoluble samples / 中国药理学通报

ABSTRACT

Aim To establish a batch of endotoxin standard for baeterial endotoxin detection of insoluble samples.Methods Candidate A and candidate B were prepared by freeze -drying bacterial endotoxin without excipient.The two batches of candidates were calibrated by three methods, including 13 laboratories for gel method, 9 laboratories for kinetic-turbidimetric assay and 5 laboratories for kinetic chromogenic assay.Results After statistical analysis, the geometric mean values of gel method, kinetic-turbidimetric assay and kinetic chromogenic assay calibration of candidate A were 680.1 EU, 827.0 EU and 800.8 EU, with RSD of 22.4%, 16.2% and 16.7%, respectively.The P value of variance analysis of calibration results of the three methods was 0.067, showing no significant difference.The weighted mean of potency was 774.0 EU (95% confidence interval 721.0 - 831.0, FL% 7.10).The geometric mean values of the calibration of candidate B by gel method, kinetic-turbidimetric assay and kinetic chromogenic assay method were 1 640.6 EU, 1 828.6 EU and 3 224.8 EU, with RSD of 33.9% , 47.0% and 54.4% , respectively.The P val¬ue of variance analysis of the calibration results of the three methods was 0.030, showing significant differ¬ence.Chi-square test was used to correct the weight of each method , and weighted average of the results of the three methods was used to obtain a corrected weighted average efficiency value of 1 822.7 EU (95% confi¬dence interval 1 548.7 -2 145.2, FL% 16.4).Can¬didate B was eliminated based on the results.Conclu¬sion Candidate A has become the first batch of na¬tional standard bacterial endotoxin (for insoluble sam¬ples only) approved by National Standard Substance Committee of China, and the potency is 700 EU.