Development, characterisation, and in vitro anti-tumor effect of self-microemulsifying drug delivery system containing polyphyllin I.

Polyphyllin I (PPI), an effective active ingredient in Paris polyphylla, has a diverse set of pharmacological properties. However, due to its poor solubility and oral absorption, its application and development are limited. In the study, we were committed to improving the solubility of PPI by developing a self-microemulsifying drug delivery system of PPI (PPI-SMEDDS), screening the best preparation process, and evaluating the quality and the in vivo pharmacokinetics of PPI, and PPI-SMEDDS following oral administration to rats were also studied. In addition, the pharmacological activities against human lung adenocarcinoma cell A549 in vitro were assessed. The best formulation had 15.89% ethyl oleate, 47.38% Cremophor RH40, and 36.73% 1,2 propylene glycol. The produced PPI-SMEDDS was clear and transparent, with an average particle size of 24.51 nm and a zeta potential of -17.54 ± 0.51 mV. In vitro, the cumulative release rate of PPI-SMEDDS was nearly 80% within 2 h. PPI-SMEDDS had a substantially greater area under the curve than PPI following oral treatment in rats, and the relative bioavailability of PPI in rats was 278.99%. More importantly, the anti-tumor effect of PPI-SMEDDS in vitro was significantly greater than that of PPI. These findings suggested that PPI-SMEDDS has the potential to improve the solubility, oral bioavailability of PPI, and anti-tumor effect, laying the groundwork for future research on the new PPI dosage form.