The preparation and investigation of spinosin–phospholipid complex self‐microemulsifying drug delivery system based on the absorption characteristics of spinosin

Objectives The aim of this research was to investigate the intestinal absorption characteristics and mechanisms of spinosin ( SPI ), and a new dosage form was prepared to increase the intestinal absorption of SPI . Methods In this study, the intestinal absorption characteristics and mechanisms of SPI were first investigated using in situ absorption model and Caco‐2 monolayer model. Subsequently, the phospholipid complex ( PLC ) loaded with SPI was prepared followed by a self‐microemulsifying drug delivery system ( SMEDDS ) technique for developing a more efficient formulation. Key findings The results showed that the absorption rate constant (0.02 h −1 ) and absorption percentage (10%) of SPI were small. Paracellular and active transport pathways mainly mediated the intestinal absorption of SPI . Moreover, SPI ‐ PLC ‐ SMEDDS showed a nanoscale particle size and excellent dispersibility in vitro . The cellular uptake and transportation properties of SPI ‐ PLC ‐ SMEDDS in the Caco‐2 cell model were improved significantly. Besides, a statistically dramatically higher oral bioavailability (almost fivefold) was observed following the oral administration of SPI ‐ PLC ‐ SMEDDS than free SPI on the basis of pharmacokinetic experiment results. Furthermore, the SPI ‐ PLC ‐ SMEDDS exhibited certain immunization. Conclusions SPI ‐ PLC ‐ SMEDDS could be a promising oral drug delivery system to improve the absorption of SPI .