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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 Souza1, Antônia de Sousa Leal2, Louise Cristina Freitas Saraiva1Ana Cristina Sousa Gramoza Vilarinho3, Jackson Roberto Guedes da Silva Almeida4Lívio César Cunha Nunes1,*
Postgraduate Program in Pharmaceutical Sciences, Federal University of Piauí (UFPI), Health Sciences Center, University Campus Minister Petrônio Portella, Pharmacy Course, Ininga, CEP 64049-550 – Terezina, PI, Brazil.
Federal University of Maranhão (UFMA), University Campus of Grajaú, Avenida Aurita Maria dos S. B. Sousa, 2010 – Loteamento Frei Alberto Beretta, Bairro Extrema, CEP 65940-000 – Grajaú, MA, Brazil.
Program of Post-Graduation in Therapeutic Innovation, Federal University of Pernambuco (UFPE), Avenida Professor Moraes Rego, 1235 – Cidade Universitária, CEP 50670-901 – Recife, PE, Brazil.
Postgraduate Program in Natural Resources of the Semi-Arid, Federal University of the São Francisco Valley (UNIVASF), Avenida José de Sá Maniçoba, s/n, Centro, CEP 56304205 – Petrolina, PE, 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.