Quality by Design-Steered Development of Stealth Liposomal Formulation of Everolimus: A Systematic Optimization and...

Everolimus is a drug approved for the treatment of breast cancer with HR+ and advanced breast cancer reoccurring in postmenopausal women. The oral administration of EVE has been observed to have low oral bioavailability and severe epithelial cutaneous events that include rashes and lip ulceration followed by mouth ulceration after oral administration.

The present research aimed to enhance the bioavailability by loading the EVE into a stealth liposomal formulation (S-EVE-LIPO) intended for intravenous administration.

The surface of the liposomes was modified with vitamin E TPGS, which prolongs the systemic circulation of the drug and provides additional benefits like inhibition of the P-gp efflux pump and acting synergistically with EVE.

The formulation was prepared using the thin film hydration method and optimized using a D-optimal mixture design. ANOVA suggested the significance of the proposed mathematic model, and the optimized formulation was generated by design expert software. The optimized formulation (S-EVE-LIPO) was observed with nanometric size (99.5 ± 3.70 nm) with higher encapsulation efficacy (81.5 ± 2.86 %). The S-EVELIPO formulation indicated a sustained release profile as 90.22% drug release was observed in 48 h, whereas the formulation without vitamin E TPGS (EVE-LIPO) released only 74.15 drugs in 24 hours. In vitro cytotoxicity study suggested that the presence of vitamin E TPGS lowers the IC₅₀ value (54.2 ± 1.69), increases the cellular uptake of the formulation, also increases the generation of ROS, and shows better hemocompatibility.

Vitamin E TPGS could be set as a vital additive to improve therapeutic efficacy and reduce offsite toxicity and dosing frequency.