Detection of 4a,5-dihydropravastatin as Impurity in the Cholesterol Lowering Drug Pravastatin

Dihydro analogues are known byproducts of the fermentative production of statins and cannot be detected with existing pharmacopoeia analysis methods. We detected dihydropravastatin in most commercial formulations of pravastatin with LC-MS, in some cases in levels requiring identification. In fermentation broth samples of the single step production of pravastatin, we detected and identified for the first time 4a,5-dihydropravastatin, and confirmed that after several recrystallization steps this impurity can be fully removed from the pravastatin powder.

Automated summary

The study found that dihydropravastatin was detected in most commercial formulations of pravastatin with LC-MS, and 4a,5-dihydropravastatin was first detected and identified in fermentation broth samples of single step pravastatin production. This impurity can be fully removed from pravastatin powder through several recrystallization steps.