Nanoencapsulation of Nimodipine in Novel Biocompatible Poly(propylene-co-butylene succinate) Aliphatic Copolyesters for Sustained Release

Biocompatible poly(propylene-co-butylene succinate) (PPBSu) copolyesters, containing up to 50 mol% butylene succinate units, were synthesized by the two-stage melt polycondensation method (esterification and polycondensation). The copolymers were fully characterized and biocompatibility studies were also performed. They were proved to be biocompatible and they were used as polymer matrices for the preparation of drug loaded nanoparticles. Nimodipine was selected as a model hydrophobic poorly water soluble drug. From the results obtained by dynamic light scattering (DLS) and scanning electron microscopy (SEM), drug loaded copolymer nanoparticles were found to exhibit a spherical shape and their mean diameter appeared in the range of 180–200 nm. Fourier Transformation-Infrared Spectroscopy (FTIR) spectra indicated that no chemical interaction between the drug and the matrix could be justified, while Wide-Angle X-Ray Diffraction (WAXD) patterns proved a low degree of crystallinity of Nimodipine in the nanoparticles. The release behavior of the model drug from nanoparticles was also investigated in order to identify modifications and find out any possible correlation between the chemical composition of the polymer matrix and the drug release rates.