Quantitative reflectance spot test for the determination of acetylsalicylic acid in pharmaceutical preparations

Abstract

Este trabalho descreve um método para a determinação quantitativa de ácido acetilsalicílico (ASA) utilizando procedimento "spot test" e reflectância difusa. O método é baseado na formação do complexo de cor roxa intensa entre o ácido salicílico, obtido a partir da hidrólise alcalina do ASA, e íons Fe(III). O procedimento proposto permite a análise de medicamentos contendo ASA de forma fácil e simples, uma vez que não é necessário fazer separações. A reflectância da mistura final, colocada sobre um disco de papel de filtro, é medida diretamente. Foram analisados nove medicamentos comerciais contendo ASA cujos resultados apresentaram um desvio padrão relativo médio de 0,9%. O limite para a determinação quantitativa é de 0,6 mg de ASA na solução de trabalho. As análises feitas com o método proposto foram comparadas com outras análises, das mesmas amostras, segundo o procedimento recomendado pela "United States Pharmacopoeia", onde se observou um desvio padrão relativo de 0,6%. Compararam-se os dois métodos utilizando-se o teste t de Student. Para um grau de liberdade ν = 4 (ν = n 1 + n 2 -2) e um limite de confiança α = 0.05, onde t = 2,78, todos os resultados foram concordantes.This paper describes a quantitative reflectance spot test procedure for the determination of acetylsalicylic acid (ASA) in pharmaceutical preparations. The method is based on the reaction of salicylic acid, obtained from the hydrolysis of ASA, with Fe(III) forming a deep blue-violet compound. Medicines containing ASA can be easily analyzed by the proposed method as it is not necessary to do any separation. The final mixture is placed on a sheet of filter paper, and the reflectance is directly measured. Nine commercial medicines containing acetylsalicylic acid were analyzed with the proposed method. The mean RSD was 0.9%. Results were compared with those obtained with the United States Pharmacopoeia recommended procedure (RSD 0.6%). The quantitative detection limit is 0.6 mg ASA in the working solution. For a degree of freedom ν = 4 (ν = n 1 + n 2 -2) and a confidence coefficient α = 0.05 all the results agree under the tabulated t-Student test value (2.78).

Square-wave voltammetric determination of acetylsalicylic acid in pharmaceutical formulations using a boron-doped diamond electrode without the need of previous alkaline hydrolysis step

“…Several other methods for ASA determination in pharmaceuticals formulations, some of them combined with a flow-injection system, were also proposed; for example, the quantitative reflectance spot test, 8 spectrophotometric, [9][10][11] fluorimetric, 12 and chromatographic 13,14 methods. The use of HPLC is preferred over other methods because of the possibility of simultaneous determination of ASA and SA.…”

Quantitative Spot-Test Analysis of Metformin in Pharmaceutical Preparations Using Ultraviolet-Visible Diffuse Reflectance Spectroscopy

“…[21][22][23][24][25] In the last twelve years, some successful quantitative spot-test reflectance procedures have been related, for inorganic and organic analytes, including the development of simple reflectometric equipment. [21][22][23][26][27][28][29][30][31][32][33][34][35][36][37] In the present work, a simple and reliable method based on UV-visible diffuse reflectance was developed for the determination of metformin hydrochloride in pharmaceutical preparations after reaction of this substance with Ni…”

Determination of ambroxol in syrups using diffuse reflectance spectroscopy

“…13,14 However, as far we know, there is no any reflectometric method for the determination of ambroxol related in the literature. Recently were reported reflectometric methods for the determination of acetylsalicylic acid 15 and furosemide 16 in pharmaceutical preparations. Despite the fact that analytical reflectometric methods in the visible region of the spectrum are not very common, some have been recently published.…”