Development and Validation of an Assay Method for Magnesium in Soft Capsules By AAS

Dr. Le Thi Huong Hoa¹, MA. Tran Duc Lai² – ¹Hoa Binh University, ²International Institute of Drug Quality Control

Abstract:

A procedure for quantitative analysis of trace element magnesium (Mg) in soft capsules (mainly containing vitamins, trace elements and herbal extracts) using atomic absorption spectroscopy (AAS) has been established.

The sample was treated to convert the Mg compound to Mg+2 ion form in solution by heating the sample on a boiling water bath with 10% hydrochloric acid solution, with the addition of Polysorbate 80. The sample was diluted with 1% hydrochloric acid solution, with the addition of LaCl3 in the final solution for AAS measurement. The standard solutions were prepared by diluting the 1000 µg/ml magnesium stock standard solution with 1% hydrochloric acid solution. Using an atomic absorption spectrometer equipped with a Magnesium hollow cathode lamp and an acetyleneair flame, measure the atomic absorption of the standard and test solutions at the maximum spectral line of Magnesium at 285.2 nm. Calculate the results using the standard curve method.

The method validation results showed that the method has high specificity, linear range from 0.1 µg/ml to 0.5 µg/ml with correlation coefficient R2 = 0.9972, high accuracy (from 99.19 -101.39%), good repeatability with small CV% values (0.44 to 0.91%), the method’s determination range is from 0.18 to 0.32 µg/ml.

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Keywords: Soft capsules, Magnesium quantification in soft capsules, Mg quantification, AAS-Mg.