Determination and pharmacokinetic comparison of rhein in rats after oral dosed with Da‐Cheng‐Qi decoction and Xiao‐Cheng‐Qi decoction

Da‐Cheng‐Qi decoction (DCQD) is composed of dahuang, houpu, zhishi and mangxiao, while Xiao‐Cheng‐Qi decoction (XCQD) just contains dahuang, houpu, and zhishi. A validated high‐performance liquid chromatographic (HPLC) method was developed for the determination and pharmacokinetic comparison of rhein in rats. It was performed on a reversed‐phase C 18 column (150 × 4.6 mm) with a mobile phase of methanol and 0.2% acetic acid (89:11, v/v) and ultraviolet detection at 254 nm. The assay was linear over the range 30–3000 ng/mL ( r 2 = 0.9991), with mean percentage recovery of 101.4%. The RSD of intra‐ and inter‐day precision were less than 3.0%, with accuracy in the range 96.8–102.5% for each of the concentrations tested. Following oral administration, rhein plasma levels revealed curves characterized by peaks at 20.5 and 30.1 min corresponding to dosages of 15 mg/kg (XCQD) and 20 mg/kg (DCQD) at mean concentrations of 1184.67 and 1814.27 ng/mL, respectively. The half‐lives of rhein from XCQD and DCQD were 45.3 and 139.6 min, respectively. AUC (0–12h) of rhein after oral dosage with XCQD and DCQD were 3435.68 and 5382.25 µg/L h, respectively. The pharmacokinetic parameters may be used to guide the clinical prescription compatibility of traditional Chinese prescriptions related to dahuang and mangxiao. Copyright © 2007 John Wiley & Sons, Ltd.