Nanostructured DPA- MPC- DPA triblock copolymer gel for controlled drug release of ketoprofen and spironolactone.

Objective Uncontrolled rapid release of drugs can reduce their therapeutic efficacy and cause undesirable toxicity; however, controlled release from reservoir materials helps overcome this issue. The aims of this study were to determine the release profiles of ketoprofen and spironolactone from a pH-responsive self-assembling DPA- MPC- DPA triblock copolymer gel and elucidate underlying physiochemical properties. Methods Drug release profiles from DPA₅₀- MPC₂₅₀- DPA₅₀ gel ( pH 7.5), over 32 h (37 °C), were determined using UV-Vis spectroscopy. Nanoparticle size was measured by dynamic light scattering ( DLS) and critical micelle concentration ( CMC) by pyrene fluorescence. Polymer gel viscosity was examined via rheology, nanoparticle morphology investigated using scanning transmission electron microscopy ( STEM) and the gel matrix observed using cryo-scanning electron microscopy (Cryo- SEM). Key Findings DPA₅₀- MPC₂₅₀- DPA₅₀ copolymer (15% w/v) formed a free-standing gel ( pH 7.5) that controlled drug release relative to free drugs. The copolymer possessed a low CMC, nanoparticle size increased with copolymer concentration, and DLS data were consistent with STEM. The gel displayed thermostable viscosity at physiological temperatures, and the gel matrix was a nanostructured aggregation of smaller nanoparticles. Conclusions The DPA₅₀- MPC₂₅₀- DPA₅₀ copolymer gel could be used as a drug delivery system to provide the controlled drug release of ketoprofen and spironolactone. [ABSTRACT FROM AUTHOR]