Study of the Composition of Polycaprolactone/Poly (Ethylene Glycol)/Polycaprolactone Copolymer and Drug-to-Polymer Ratio on Drug Loading Efficiency of Curcumin to Nanoparticles

Natural products derived from plants play a significant function in healthcare in many cultures, both ancient and modern. curcumin (CUR) is a chemical constituent of turmeric with anticancer activity, but its poor water solubility limits its use clinically.
To improve the bioavailability and water solubility of curcumin, we synthesized five series of poly (caprolactone)-poly (ethylene glycol)- poly (caprolactone) (PCL-PEG-PCL) triblock copolymers. The structure of the copolymers was characterized by HNMR, FT-IR, DSC, and GPC techniques. The nanoparticles (NPs) were prepared using a solvent evaporation method. To achieve the best delivery system, we assigned the effect of the length of the copolymers’ hydrophilic and hydrophobic chains on the encapsulation of hydrophobic CUR, performed entrapment efficiency and drug loading assignments, as well as evaluated the particle distribution and in vitro release using the direct dispersion method.
CUR was encapsulated with 71% and 83% efficiency in biodegradable nanoparticulate formulations, based on NP4 and NP5. Dynamic laser light scattering (DLS) indicated a particle diameter of 112 nm and 110 nm for NP4 and NP5, respectively. FT-IR and DSC analysis of the NPs showed that CUR was encapsulated into the NPs. The in vitro release experiments showed that NP5 controlled the release of CUR more effectively, with only 51% of CUR released after 120 hours.
The results indicate the successful formulation of curcumin-loaded PCL-PEG-PCL nanoparticles and improved water solubility of curcumin, which may have potential application in cancer treatment.