Nanoemulsões à base de curcuminoides e ácido oleico para uso tópico no tratamento de lesões cutâneas

Abstract

Curcuminoids have attracted the interest of scientists because they exhibit various pharmacological activities, including antioxidants, anticancer, anti-inflammatory, antimutagenic, anticoagulant, anti-infectious and antibacterial. However, for these active ingredients to be used in pharmaceuticals, it is necessary to associate them with excipients that potentiate their action, increasing their solubility and bioavailability. The objective of this study is to encapsulate the curcuminoids in nanoemulsions, containing oleic acid as oily phase and Pluronic® F127 as stabilizer, in order to use this formulation in the treatment of Pressure Injury. Compatibility and preliminary stability studies were performed to verify the feasibility of the proposed formulation. The results obtained in the compatibility study, using the techniques of FTIR, TG (DTG) and HPLC, are comparable and conclusive as to absence of physical or chemical interaction in the mixture (1:1:1) of the active principles and their excipients. The stability study characterized the nanoemulsions as stable, with acidic pH and indicative of the expiration date of 12 months. Through the factorial planning performed, having the hydrodynamic diameter (Dh) and zeta potential as response variables, the most stable nanoemulsions were selected, E3, E6 and E9. Their Dh values are in the range of 198-265 nm and zeta potential between -30.4 and -34.8 mV. The polydispersity index data (0.150-0.226) characterized the nanoemulsions with moderately polydisperse particle size distribution. The most stable nanoemulsions indicated in the rheological analyzes that they do not behave as a gel and are characterized as non-Newtonian fluids and classified as Bingham plastics. The Emulsions E3, E6 and E9 obtained Encapsulation Efficiency (EE) above the 99% and in the in vitro release study showed up to 13.7% release of the curcuminoids within 24 hours, with a controlled release profile. The selected nanoemulsions presented values of IC50 (≈0.3 mg/mL), in the antioxidant assay by DPPH free radical capture, very close to the standard used, BHT (0.29 mg/mL), indicating that the proposed nanoemulsions presented results satisfactory and should act on pressure lesions as continuous sources of antioxidant and anti-inflammatory.