New PPARα Agonist A190-Loaded Microemulsion for Chemotherapy-Induced Peripheral Neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is a serious side effect of anticancer agents with limited effective preventive or therapeutic interventions. Although fenofibrate, a peroxisome proliferator-activated receptor-alpha (PPARα) agonist, has demonstrated neuroprotective and analgesic properties, its clinical utility is hindered by low receptor affinity, poor subtype selectivity, and suboptimal bioavailability. A190, a highly selective and potent nonfibrate PPARα agonist, offers a promising alternative but is limited by poor aqueous solubility, resulting in reduced oral bioavailability and therapeutic efficacy. To address these limitations, an optimized oil-in-water (o/w) microemulsion formulation was developed using Box-Behnken design to enhance the solubility and intestinal permeability of A190. The A190 microemulsion exhibited physical stability with a droplet size of approximately 100 nm and a drug loading efficiency of greater than 95%. The effective and apparent permeability of A190 from the microemulsion was significantly higher compared to that of free A190 dispersion, respectively. Additionally, no significant impact on the cell viability was observed, indicating less toxicity and a good biocompatibility of the formulation components. The oral bioavailability of A190 microemulsion was approximately 5-fold higher compared to A190 dispersion, demonstrating the microemulsion's potential to greatly enhance the oral bioavailability of hydrophobic drugs. Furthermore, our findings reveal that orally administered A190 microemulsion effectively reduced CIPN-induced mechanical hypersensitivity, likely mediated through PPARα activation. A190 microemulsion was found to be equally effective at reducing the chronic inflammatory complete Freund's adjuvant-induced pain. These results underscore A190s potential as a nonopioid therapeutic candidate, utilizing a novel microemulsion formulation for the management of chemotherapy-induced neuropathic pain and chronic inflammatory pain.