It has been suggested that oral absorption of low-permeable P-glycoprotein (P-gp) substrates can be increased through saturation of P-gp. For BCS class IV drug substances, saturating P-gp is challenging due to low aqueous solubility. The present study investigated if the BCS IV drug substance etoposide could be solubilized to a concentration saturating P-gp after oral administration. A formulation consisting of 10% (w/v) of pluronic® F-127 and polyvinylpyrrolidone/vinyl acetate (PVP/VA), and 57% (v/v) ethanol enhanced etoposide's solubility approximately 100 times (16 mg mL−1) compared to its aqueous solubility. In vitro, this formulation was stable upon dilution in simulated intestinal fluid. In male Sprague-Dawley rats, oral administration of increasing solubilized etoposide doses using the formulation matrix increased the AUC0-∞ of etoposide dose-proportionally but resulted in a lower absolute oral bioavailability (F) and rate of absorption as compared to control. At the highest investigated dose (100 mg kg−1), AUC0-∞ and Cmax were significantly increased by 2.9- and 1.4-fold, respectively, compared to control dosed at 20 mg kg−1. A single oral dose of 20 mg kg−1 zosuquidar followed by 20 mg kg−1 oral etoposide increased F 8.6-fold. In conclusion, a stable formulation with improved etoposide solubility was developed, yet the formulation did not result in increased oral bioavailability of etoposide.
Bibliografisk noteFunding Information:
We thank the staff at the animal facility at Janssen Pharmaceutica NV for help with performing the animal study. Greet Janssen at the animal facility is thanked for assisting with the in vivo study and preparing the samples for bioanalysis. We thank the staff at the Drug Product Development, Developability, at Janssen Pharmaceutica NV. Special thanks go to Marc Du Jardin and Kris Van Dijck for their help in the lab and logistic support.
© 2020 Elsevier B.V.