Polymeric Micelle Soluplus, Mediated Improved Solubilization of <scp>IR780</scp> Dye for Photothermal Therapy

ABSTRACT Poor aqueous solubility remains a significant challenge in the formulation of liquid dosage forms for photothermal dyes. Among various technological strategies explored, the encapsulation of dye molecules within polymeric micelles has emerged as a promising approach in recent years. In this context, particular attention has been given to soluplus, an amphiphilic graft copolymer composed of polyvinyl caprolactam, polyvinyl acetate, and polyethylene glycol, which is capable of forming stable nanomicelles. The objective of the present study was to develop and characterize soluplus‐based nanomicelles to enhance the apparent solubility of the hydrophobic photothermal dye IR‐780 (IRSMs). Dye‐loaded soluplus micelles were successfully prepared using the thin‐film hydration method, resulting in nanoparticles with an average size of approximately 50–55 nm. The formulations were systematically evaluated for their mean particle size, zeta potential, dye encapsulation efficiency, and physical stability under storage and dilution conditions. Upon exposure to 808 nm laser irradiation, the micellar formulations exhibited a pronounced photothermal heating effect, with a significant increase in temperature, confirming their potential as effective photothermal agents for use in photothermal therapy (PTT). Moreover, the IRSMs showed significant stability with respect to long‐term storage and dilution and hence can be an ideal candidate for in vivo PTT application.