Preparation and intestinal absorption mechanism of self-assembled nanoparticles of Herpetospermum caudigerum

Abstract

In this experiment, the micro-precipitation method was used to prepare self-assembled nanoparticles of Herpetospermum caudigerum Wall.(MP-SAN). The process was optimized using average particle size and polydispersity index(PDI)as evaluation indexes. The mean particle size, PDI,zeta potential, and microstructure of MP-SAN were characterized. The intestinal absorption mechanism of dehydrodiconiferyl alcohol(DA)and herpetrione(Her)in MP-SAN was investigated through single-pass intestinal perfusion in rats. The optimized process parameters for producing MP-SAN were a stirring speed of 800 r·min~(-1),stirring time of 5 min, and rotary evaporation temperature of 40℃. The resulting MP-SAN exhibited a spherical-like structure and uniform morphology, with a mean particle size of(267.63±13.27) nm, a PDI of 0.062 0±0.043 9,and a zeta potential of(-46.18±3.66) mV. The absorption rate constant(K_a)and apparent permeability coefficient(P_(app))of DA in the ileal segment were significantly higher than those in the jejunal segment(P<0.05). However, there was no significant difference in the absorption of Her between the ileal and jejunal segments. Intestinal absorption parameters of DA and Her tended to increase with increasing drug concentration. Specifically, the K_a and P_(app) of DA in MP-SAN in the high-concentration group were significantly higher than those in the low-concentration group(P<0.01). The addition of verapamil, a P-glycoprotein inhibitor, did not significantly affect the intestinal absorption of DA and Her. However, the absorption of both DA and Her in MP-SAN was significantly increased by the addition of indomethacin(P<0.05),suggesting that DA and Her may be substrates for multidrug resistance-associated protein 2.