Micellar solutions of Pluronic F127 for ocular drug delivery

Abstract The goal of this research was to prepare drug‐encapsulated polymeric micelles for delivery to the posterior segment of the eye. Solutions of surface active PF127 at the critical micellar concentration (CMC) were prepared in deionized water (DI water) and phosphate buffer (PBS). The CMC of PF127 solution in DI water and PBS solution were found to 0.21 ± 0.04 and 0.16 ± 0.05% (w/v), respectively. In addition, the micellization of the PF127 was observed around 25 and 21°C in DI water and PBS solution, respectively by DSC analysis. The hydrodynamic diameter of the PF127 micelles were found to range between 3 and 4 nm with polydispersity indices ranging between 0.35 ± 0.22 and 0.96 ± 1.52. Curcumin (CUR), a natural dietary compound having an anti‐VEGF properties, was successfully loaded into PF127 copolymers by the thin‐film hydration method. The CUR‐loaded PF127 micelles were confirmed by several characterization techniques including DLS and HPLC. A detailed study of the effect of experimental conditions on both the particle size and drug encapsulation efficiency (%EE) of the CUR micelles was also carried out. CUR‐loaded PF127 micelles with small particle sizes (around 15 nm, PDI = 0.19 ± 0.13) and %EE around 10% were observed at high centrifugation speed. Also, increasing the copolymer‐to‐drug ratio resulted in higher %EE (>90%). Additionally, the CUR‐loaded PF127 micelles were easy to reconstitute in water by manual shaking after lyophilization. These results suggest that PF127 micelles are a promising carrier for delivery of CUR to the eye. Future work will study in more detail about the physicochemical properties and the ability of these micelles to transport CUR across ocular barriers in ex vivo and in vivo trials.