Adequacy of methodologies for analysis of sodium and potassium by atomic absorption spectroscopy in oral rehydration salts

Abstract

This article discusses the suitability of two methods of analysis by atomic absorption spectroscopy for the quantification of sodium and potassium in oral rehydration salts, based on USP and AOAC methodologies for a pharmaceutical laboratory in Costa Rica. First we inquired into official methods applicable to the determination of sodium and potassium. From these, tests were proposed that allowed to adjust the range of concentrations of work for atomic absorption spectroscopy; It was obtained that for the sodium the range is suitable between 0.5 and 1.0 μg / ml and for potassium between 0.5 - 1.5 μg / ml. In a second stage the preparation of the sample was considered considering two forms, reconstituting the total content of the presentation of the drug and by the dilution of a known sample mass, to determine which procedure was most effective; Reconstitution was the most appropriate. In addition, the validation of both methods was completed considering the parameters: interval, linearity, accuracy, repeatability and intermediate accuracy, and satisfactory results were obtained according to the guidelines of the Ministry of Health. Finally, three batches of the product in question with the validated methods were subjected to sodium and potassium analysis, and very favorable results were obtained within the USP specification (90-110%).