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Research Article  |  Published: 18 October 2018

Development and Validation of Analytical Method by UV-Vis Spectrophotometry for Quantification of Alpha-Lipoic Acid

Grasielly Rocha Souza, Antônia de Sousa Leal, Louise Cristina Freitas Saraiva, Ana Cristina Sousa Gramoza Vilarinho, Jackson Roberto Guedes da Silva Almeida and Lívio César Cunha Nunes*

Federal University of Piauí (UFPI), Health Sciences Center, University Campus Minister Petrônio Portella, Pharmacy Course, Ininga, CEP 64049-550 – Terezina, PI, Brazil


Alpha-lipoic acid (alpha-L1) is present in prokaryotic and eukaryotic cells, playing a central role in energy metabolism. Many studies have already been carried out to verify the therapeutic potential of this compound since it has an excellent antioxidant activity. However, there is no monograph present in the Brazilian Pharmacopoeia, so this study was carried out with the objective of developing and validating an analytical method by UV-Vis spectrophotometry to quantify alpha-LA. For this, the alpha-LA solubility was evaluated against different solvents, besides performing a spectrophotometric scan to determine the maximum wavelength of absorption. For validation, the parameters required by RDC nº, 166 of 2017 were verified: selectivity, linearity, limits of detection (DL) and quantification (QL), precision, accuracy and robustness. The compound showed high solubility in solvents of intermediate polarities, such as dichloromethane and ethanol, and the maximum absorption wavelength was 334 nm. The method was selective since there was no absorption of the other components of the formulation at the selected wavelength; linear with r2> 0.99; accurate, since it presented values of intermediate precision and statistically significant repeatability; besides being accurate and robust.

Alpha lipoic acid; antioxidant; analytical method; validation; spectrophotometry; thioctic acid.