Effect of particle size on in vitro and in vivo behavior of astilbin nanosuspensions

In this study, the effect of particle size on in vitro and in vivo behavior of astilbin nanosuspensions (AT-NSs) was investigated. AT-NSs with three different particle sizes (215.17 +/- 4.83 nm, 496.51 +/- 12.94 nm, and 803.34 +/- 9.06 nm) were prepared using a simplified wet media milling technique by adjusting milling time. SEM and XRPD results showed that the three AT-NSs had similar appearance and crystalline state. The dissolution of AT-NSs was particle size dependent and in an order of 215.17 nm > 496.51 nm > 803.34 nm, however the AUC(0-infinity) of pharmacokinetics was in an order of 496.51 nm > 803.34 nm > 215.17 nm. AT-NSs with a larger particle size showed a higher accumulation in lung and liver because of reticuloendothelial system (RES). In conclusion, particle size had obvious impact on dissolution, pharmacokinetics and tissue distribution of AT-NSs, and the optimal particle size was 496.51 nm for the oral administration of AT-NSs.