Simultaneous determination of multiple constituents of Qi-Lin pill by UPLC-MS/MS: Applications to pharmacokinetics and testicular tissue distribution in rats

Qi-Lin pill (QLP) is an effective traditional Chinese medicine prescription (TCMP) that has been used for the treatment of the oligoasthenozoospermia in China. Recently, some articles described the pharmacological effects of QLP and multiple ingredients in QLP contribute to its effects. However, the pharmacokinetic and target tissue distribution data of QLP are still unknown. In the present study, according to the Bioanalytical Method Vali-dation Guidance of FDA, a sensitive and selective UPLC-MS/MS method was developed and validated for simultaneous determination of multiple constituents in rat plasma and testicular tissue, including morusimic acid A, codonopyrridium B, magnoflorine, emodin, 2,3,5,4 '-tetrahydroxystilbene-2-O-beta-D-glucoside (THSG), eclip-tasaponin A, paeoniflorin, albiflorin, gallic acid, danshensu, salvianolic acid A, catechin, isosinensetin, nobiletin, formononetin, calycosin, icariside II, icariin and epimedin C. For 19 analytes, the LLOQs reached 0.01-4 ng/mL. And all calibration curves showed favorable linearity (r >= 0.9903) in linear ranges. The intra-day and inter-day precision (relative standard deviation) for all analytes was less than 14.92 %, and the accuracies (as relative error) were in the range of -6.44 % to 6.22 %. Extraction recoveries and matrix effects of analytes and IS were acceptable. All analytes were stable during the assay and storage in plasma samples. The method was successfully applied for the pharmacokinetics and testis distribution of multiple chemical constituents in QLP after a single oral dose. As a result, high exposure of danshensu, gallic acid, paeoniflorin and albiflorin were observed in rat plasma and testicular tissue. Among the flavonoids, isosinensetin and nobiletin had high exposure in testicular tissue. Moreover, alleviation of progesterone reduction was evaluated in H2O2-induced R2C leydig cells, and danshensu, gallic acid, paeoniflorin, albiflorin and nobiletin showed potent activity. Therefore, these five components were considered to be the effective components of QLP due to their relatively high exposure in vivo and biological activity. This finding also provided relevant information on action mechanism of QLP in the treatment of oligoasthenozoospermia.