DESENVOLVIMENTO E AVALIAÇÃO IN VITRO DE NANOPARTÍCULAS DE PLGA E PLGA-P80 CONTENDO MELATONINA

Abstract

Melatonin is a natural hormone whose primary production occurs in the pineal gland, possessing numerous physiological and pharmacological functions among which stands out for its high antioxidant character with direct and indirect actions on the reduction of free radicals, which may be closely related to its neuroprotective role in diseases such as parkinson's and alzheimer's. However, exogenous melatonin administration has some unfavorable limitations that may impair their effectiveness such as sensitivity to oxidation and extensive first-pass metabolism when administered orally, consequently has a short half-life ranging from 10 to 60 minutes difficulting the production an effective therapeutic dose. Factors such as these make use of nanotechnology interesting for the development of an adequate system of release of melatonin in the search to overcome such limitations and improve its pharmacokinetic and pharmacodynamic characteristics, especially orally, since this pathway is most favorable when compared to other. First, was developed and validated by High Performance Liquid Chromatography analytical method for quantification of melatonin indirectly present inside the nanoparticles. The mobile phase consisted of acetonitrile:water (65:35) flowed at 0.9 mL/min with PDA detector set at 220 nm. This method had a suitable linearity, specificity, precision, accuracy, limits of detection and quantification and robustness according to current guidelines. Obtained two formulations of polymeric nanoparticles containing melatonin technique developed by emulsification and solvent evaporation coated with polysorbate 80 (PLGA-P80) and uncoated (PLGA) with a mean diameter of 212.2 ± 16.4 and 186.6 ± 14,3 nm, polydispersity index of 0.09 ± 0.02 and 0.07 ± 0.03 and encapsulation efficiency and 26.28 ± 11.57 40.95 ± 10.12%, respectively. The release profile presented by nanoparticles PLGA and PLGA-P80 was the second order, featuring an initially rapid release of melatonin denominated "burst effect", followed by a slower release. The total release of melatonin at 120 hours was 35.65 ± 1.65 % from PLGA and 26.7 ± 0.75 % in PLGA-P80. The applicability of the nanoparticles was analyzed by hemolysis in vitro study demonstrated the biocompatibility of nanoparticles and the antioxidant potential of the same under the radical scavenging capacity ABTS•+ (2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt). In all time of radical inhibition occurred in proportion to the concentration of melatonin, where its antioxidant potential after the encapsulation process to keep up with expressive action obtained mainly in PLGA nanoparticles, showing IC50 more effective 0.2 ± 0.02 μg/mL in 72 hours compared to free melatonin and PLGA-P80 of 0.8 ± 0.12 and 0.7 ± 0.01 μg/mL, respectively. These results suggest that these nanoparticles can be used as delivery systems for future treatments with melatonin aiming to neuroprotection against Parkinson and Alzheimer diseases.