Prediction of Passive Transport of 10 Natural Products by Liposome-based Fluorescence Technique

A simple and effective screening method for the determination of membrane permeability has been presented and demonstrated by the rapid analysis of ten kinds of traditional Chinese medicine (TCM) components. Fluorescent 1,6-diphenyl-1,3,5- hexatriene (DPH) liposomes were prepared in this study and were used to predict the membrane permeability of ten kinds of natural products. Fluorescence quenching percentages of ten kinds of natural products on the DPH liposomes were thus determined, and their effective intestinal permeability coefficient (Peff) was determined using rat single-pass intestinal perfusion experiments. The data show that a good linearity (r = 0.85) was observed between the fluorescence quenching percentage and Peff. Furthermore, the erythrocyte membrane was labeled using DPH, and then the erythrocyte-membrane fluorescence quenching percentage resulting from ten kinds of natural products was determined. After comparing the liposome and erythrocyte-membrane fluorescence quenching percentages, it was also found that a good linearity (r = 0.93) existed between these two methods. Overall, fluorescent liposomes could be simply and sensitively employed to predict passive transport of natural products and permeability in erythrocyte membrane, and fluorescent liposomes were thus an attractive alternative to current rat intestinal experiments and erythrocyte membrane model. This protocol will be quite promising in predicting passive drug absorption during lead compound selection and drug development.