Resveratrol-Loaded Polymeric Nanoparticles: Validation of an HPLC-PDA Method to Determine the Drug Entrapment and Evaluation of Its Antioxidant Activity

Poly(lactic acid) (PLA) and PLA-poly(ethylene glycol) (PLA-PEG) nanoparticles containing resveratrol (RVT) were developed, and their antioxidant activity was evaluated. An analytical method using high performance liquid chromatography (HPLC)/photodiode array (PDA) detection was also developed and validated for RVT determination in nanoparticles. The mobile phase consisted of methanol : water (51 : 49, v/v) flowed at 0.9 mL/min, and the PDA detector was set at wavelength of 306 nm. The mean diameter of the nanoparticles varied between 180 and 220 nm, and the encapsulation efficiency of RVT ranged from 60% to 88%. The nanoparticles containing RVT were evaluated for their ability to scavenge the radical (2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) (ABTS•⁺). The profile obtained from the PLA nanoparticles containing RVT demonstrated that after 24 h, there was almost no increase in antioxidant activity, which was lower than that of the free RVT and RVT-loaded PLA-PEG nanoparticles. For PLA-PEG nanoparticles, the radical-scavenging activity of RVT was shown to increase with time, and after 48 h, it was similar to that observed with free RVT.