Drug product development and pharmacological evaluation of a sparingly soluble novel camptothecin analog for peroral administration

摘要

This work focused on the developmental aspects, pharmacokinetic evaluation, and pharmacological assessment of a drug inclusion complex for a novel camptothecin analog (CA) and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD). Camptothecins analog belong to topoisomerase-I inhibitor class of compounds with proven anti-tumor activity but exhibit poor solubility. To enhance solubility a drug inclusion complex with cyclodextrin was developed using a spray-drying process. The powder complex characterized using DSC, XRPD, FT-IR, and 1H NMR techniques confirmed interaction of cyclodextrin with the CA indicating formation of a true complex wherein the drug is encapsulated in the cyclodextrin cavity. The saturation solubility and dissolution kinetics of drug complex evaluated in a discriminating medium showed significantly higher solubility and faster dissolution as compared to a physical mixture or powder blend comprising of drug and cyclodextrin. Pharmacokinetic (PK) studies in Wistar rats indicated a significant increase in the rate and extent of absorption for the drug complex as compared to a nanoparticulate dispersion that was used as the positive control. Pharmacological activity following peroral administration of drug complex in athymic nude mice with implanted tumors revealed that the tumor inhibition activity was equivalent to commercially available intravenous (IV) formulation with comparable safety profile. These studies demonstrated for the first instance feasibility of developing a safe and efficacious peroral formulation for a sparingly soluble camptothecin analog that may provide another viable, patient compliant, and cost effective option for the treatment of solid tumors.