Caracterização de nanopartículas blenda de biopolímeros (PHBV, PCL e PLLA) contendo progesterona

Abstract

The release of progesterone in cattle is performed in order to synchronize estrus. Currently this is done using intravaginal devices, yet the controlled release using biocompatible nanoparticles is an alternative that should be investigated. The use of these nanoparticles would be interesting to facilitate the management regarding the synchronization of estrous in cattle. The polymer controls the release of the drug (in this case, progesterone) and protects it from harmful ultraviolet radiation, humidity and contact with oxygen. Different polymers have been studied for encapsulation of drugs, but major attention can be given to those that present properties of biodegradability and biocompatibility. This study aims to characterize the blend nanoparticles composed by natural polymers poly(L-lactic acid) (PLLA) and poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and the synthetic polymer poly(ε-caprolactone) (PCL) containing progesterone. The nanoparticles were analyzed by Fourier Transform Infrared Spectroscopy (FTIR) and the isoelectric point of nanoparticles suspensions were determined. Based on the results it was observed that all formulations of polymeric nanoparticles presented interactions between the polymers and the drug due to changes in FTIR spectra. The formulation which showed larger changes in the spectra was the blend of PHBV / PCL. Regarding to the isoelectric point analysis of the nanoparticles dispersions, pH 1 leaded to a more pronounced precipitation of nanoparticles, indicating that the isoelectric point was reached. Thus, it can be concluded that oral administration of nanoparticles would not be appropriate due to the pH of the gastric fluid (1.2), which may cause a destabilization and consequent precipitation of nanoparticles.