Improved dissolution rate and oral bioavailability of lovastatin in red yeast rice products.

Lovastatin, categorized as a class II compound according to the Biopharmaceutics Classification System, is mainly responsible for the blood cholesterol lowering effect of red yeast rice (RYR). The aim of this study was to compare the dissolution rate, physical state, and oral bioavailability of lovastatin in three RYR products (LipoCol Forte, Cholestin, or Xuezhikang) to those of two lovastatin tablets (Mevacor or Lovasta). The results showed that the dissolution rate of lovastatin in various dissolution media in the registered RYR products was faster and higher than that of lovastatin in lovastatin tablets. Powder X-ray diffraction and differential scanning calorimetry patterns showed that the crystallinity of lovastatin was reduced in RYR products. In human studies, the AUC and Cmax values for both lovastatin and its active metabolite, lovastatin acid, were significantly higher in volunteers receiving LipoCol Forte capsules or powder than in those receiving lovastatin tablets or powder. In addition, shorter and less variable Tmax values were observed in volunteers taking LipoCol Forte than in those taking lovastatin tablets. These findings suggest that the oral bioavailability of lovastatin is significantly improved in RYR products as a result of a higher dissolution rate and reduced crystallinity.