Formulação e análise da estabilidade físico-química e microbiológica de um fitocosmético de uso tópico à base de cúrcuma (Curcuma longa L.).

Abstract

The richness of Brazilian biodiversity has encouraged consumers to give preference to products of natural origin as an alternative to the application of synthetic products. Thus, Curcuma longa L. is a herbaceous, perennial, tuberous herb, native to South and Southwest Asia, which develops in countries with tropical and subtropical climates. The presence, mainly, of polyphenolic groups qualifies this plant for studies to prove its pharmacological properties, in addition to having curcumin as its main bioactive compound, from which the development of topical gels proves to be a promising pharmaceutical form. The main challenge in employing this bioactive in topical formulations, however, lies in the proof of its stability, given the loss of its antioxidant activity. The proposed study aimed to evaluate the physicochemical and microbiological stability of a topical formulation containing Curcuma longa L. In view of this, a 2% gel was prepared and separated into protected and unprotected aliquots from light that were subjected to preliminary stability, with centrifugation and freeze-thaw cycle, and accelerated stability tests at 37 ± 2 ºC. Tests for the evaluation of organoleptic characteristics, pH, microbiological analysis and dosage of curcuminoids by UV-VIS spectrophotometry technique at 429 nm were included. A homogeneous gel was obtained, consistent in appearance, shiny, non-sticky and with an orange color. In the preliminary stability tests, it was observed that the formulation remained stable in centrifugation and in the freeze-thaw cycle, and its physical characteristics, during and after the conduct of the tests, showed no changes. The pH compared to that of the control sample and the pH of the samples subjected to thermal stress in accelerated stability showed statistically significant variations. In the microbiological analysis, the evaluation remained within the criteria established by the Brazilian Pharmacopoeia. In the dosage test, the prepared curve showed good linearity, however, the concentrations obtained in the samples subjected to accelerated stability were not satisfactory, presenting an increase in the curcuminoid content with respect to the control sample. This study showed that it is feasible to prepare a gel with 2% turmeric, however its quantitative evaluation requires more studies to establish a robust methodology. This issue creates opportunities for the development of future works that can test methodologies with different extraction solvents capable of generating satisfactory data about the stability of the formulation.