Sustained release of sodium tetradecyl sulfate from injectable degradable poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) copolymers

Abstract We developed a degradable pluronic F-127 (PF-127)–based drug delivery system-poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol)–to localize STS and control its release directly at the target vein. The characteristics of the STS-loaded depot were assessed, and in vitro release profiles were quantified by high-performance liquid chromatography (HPLC). The in vivo elution behavior of STS from PF-127 was further evaluated in a rabbit vein model by administering equal doses of STS either as free drug or formulated within PF-127. This novel sustained-delivery approach provided continuous STS release for more than 14 days in vitro and achieved prolonged, high local STS levels in the rabbit ear vein for up to 28 days, while keeping systemic concentrations low. In addition, the PF-127-based drug delivery system significantly attenuated the initial burst release observed with free STS, indicating a more controlled pharmacokinetic profile. Collectively, these quantitative findings show that the PF-127-based system adds clear value over free STS by extending local exposure, reducing peak-driven losses and off-target exposure, and potentially improving therapeutic durability for the treatment of varicose veins.