Development and application of analytical method for quantification of zinc pyrithione in shampoos by UV/VIS spectroscopy / Desenvolvimento e aplicação de método analítico para quantificação de piritionato de zinco em xampus por espectroscopia UV/Vis

Abstract

Objective: develop and evaluate an analytical methodology using uv/vis spectroscopy for quantification of industrialized and compounded shampoos, and perform a physicochemical characterization in the products, including the content of zinc pyrithione. Methods: the validation of the analytical method was performed following the parameters of specificity and selectivity, linearity, precision, accuracy, and robustness established by anvisa in rdc nº 166/2017, validation of analytical procedures: text and methodology (complementary guideline on methodology dated 6 november 1996 incorporated in november 2005) and analytical procedures and methods validation for drugs and biologics (fda). The following assays of physical-chemical characterization were performed for both zinc pyrithione shampoo and placebo formulation: organoleptic characterization, ph, conductivity, content, foam index and viscosity. Results: the method was precise, repeatability obtained cv% between 3.71 and 3.91%, complying with the resolution. The study of intermediate precision also was in accordance with the resolution, which value obtained for cv% was between 3.17 and 3.79%. Results did not show statistically significant differences (p<0.005). Accuracy had a slight variation, regarding to 100% of active principle. The method was considered robust. Sample a content presented a concentration of zinc pyrithione inferior to the recommended in the literature. Conclusion: the presented methodology showed to be simple and cheap through uv/vis-spectrophotometry. It is important to characterize the final product in order to provide the desired effect.