Comparative pharmacokinetic profiles of five poorly soluble pulchinenosides in different formulations from Pulsatilla chinensis saponins extracts for enhanced bioavailability

Pulsatilla chinensis, a traditional Chinese medicine (TCM), has been used for treating amoebic diseases, vaginal trichomoniasis and bacterial infections over a long history. Now growing attention has been attracted to its antitumor activities. The purpose of this work was to compare the pharmacokinetic profiles of pulchinenosides in different formulations and to improve their oral bioavailability. Extracts of P. chinensis saponins were prepared for PRS-Na (salt forming), PRS-HPβCD (hydroxypropyl-β-cyclodextrin inclusion complex), PRS-O/W (oil-in-water emulsion) and PRS-silica (micronization), respectively. A simpler and more durable LC-MS/MS method was developed in this study for quantitative analysis of pulsatilla sapoin D, B7, B10, B11 and sapoin PD simultaneously. The four formulations enhanced saponins oral bioavailability to varying degrees, as PRS-HPβCD > PRS-silica > PRS-O/W > PRS-Na, which indicated that water-soluble preparations can obviously improve the solubility of saponins, and are helpful to increase bioavailability. In particular, hydroxypropyl-β-cyclodextrin inclusion complex was the most effective way to promote absorption of saponins, raising the F values (bioavailability) >20 times. Therefore, P. chinensis saponin molecules can be slowly released by emulsion and micronization, which can avoid the enormous Cmax appearing in HPβCD, considering the pharmacokinetics profiles. However, appropriate pharmacokinetic parameters were observed in PRS-Na, although the F value was minimum among the four preparations.