Self-microemulsifying drug delivery system-based gastroretentive in situ raft of pazopanib with enhanced solubility and bioavailability

Pazopanib hydrochloride (PZH) is a Biopharmaceutics Classification System class II drug that faces challenges at the formulation forefront including low aqueous solubility (0.043 mg/mL) and poor oral bioavailability (14-39%). The present investigation aimed to develop a self-microemulsifying drug delivery system (SMEDDS) of PZH using a blend of Capryol® 90, Labrasol®, and propylene glycol to improve its solubility. Furthermore, a sustained-release SMEDDS-based gastroretentive floating system was developed and optimized using the Central Composite Design approach of DoE. The optimized SMEDDS-based in situ gelling raft, R-SM-PZH, exhibited minimal floating lag time (3.09 ± 0.8 s), optimal viscosity (1229.4 ± 20.9 cP) and density (0.327 ± 0.15 g/mL) as compared to other formulations under study. Additionally, R-SM-PZH was evaluated for its in vitro dissolution in FaSSGF and FeSSGF, pharmacokinetic profile, and MTT assay (against NCI-H460 lung cancer cells) compared to pure PZH. A 12 h sustained release, three-fold augmentation in dissolution rate and bioavailability, and 15-fold enhancement in cytotoxicity were observed in comparison to pure PZH. Thus, the SMEDDS-based in situ gelling raft presents a promising approach to advancing the developability potential of PZH.