Temperature Sensitive Pluronic F127-Based Gels Incorporating Natural Therapeutic Agents

Pluronic F127 copolymer is used as the main component to design injectable gels for therapeutic applications. Xanthan gum is added as an excipient to improve gel properties under physiological conditions. A polyphenol bioactive compound, curcumin, is selected as therapeutic agent with beneficial effects on metabolism and many diseases. The encapsulation efficiency and stability of formulations are investigated in an aqueous environment and in acetic acid solutions. The interactions between the hydrophobic polyphenol and the polymer matrix are investigated through rheology, DLS, and FTIR spectroscopy. The viscoelasticity of gels, correlated with the network structure, is influenced by xanthan gum or acetic acid addition. FTIR analysis of curcumin incorporated into the gel provides the evidence for interaction of the phenyl rings of both keto-enol and di-keto tautomers with the polymeric matrix. The spherical curcumin-encapsulated micelles provided antioxidant properties. The kinetics of curcumin release from the Pluronic F127-based gels suggests anomalous transport phenomena controlled by diffusion through the network and hydrodynamic effects. Both gel and lyophilized form of micellar encapsulated curcumin composites exhibited good stability for long-term storage under ambient conditions.