Studies on quantitative determination methods of tacrolimus in the fermentation broth

Tacrolimus is a novel immunosuppressant,and presently the measures to analyzed the fer- mentation titer of tacrolimus are still not many.This article established two methods to detect tacrolimus in the fer- mentation broth.Method:Determination of HPLC:Determined the analysis method that the mobile phase was 0.1% phosphoric acid-acetonitrile(32:68),the velocity of flow was 1 mL·min~(-1),and product peak was detected in the 205 nm and at 50℃.Bioassay (estimation of biological potency):Used Candida albicans as identified bacterium and determined taerolimus with bioassay as antibiotics.Results:The result with HPLC was that the concentration of tacrolimus and peak area appeared excellent linearity over the range of 10-100 μg·mL~(-1),and average recovery was 99.94% (RSD=1.6% ).Also ,we found tacrolimus could inhibit Candida albicans growth strongly,and set out production of tacrolimus in the fermentation broth by bioassay,with the regresstion equation was Y=0.1285X- 1.8936 and coefficient was 0.9982.Conclusion:This bioassay method is simple,rapid,economical,and credible by comparison with HPLC.