Articles

Hikal H.O., Nizhenkovska I.V., Glushachenko O.O., Markin R.O., Syrotchuk O.A. Aspects of developing an eco-friendly method for determining azilsartan medoxomil using high-performance liquid chromatography

UDC 543.544.5.068.7;615.074
DOI: 10.15407/zht2024.22-24.017

Hikal H.O., Nizhenkovska I.V., Glushachenko O.O., Markin R.O., Syrotchuk O.A.

Aspects of developing an eco-friendly method for determining azilsartan medoxomil using high-performance liquid chromatography

The article discusses the use of aqueous-ethanol mobile phases for the chromatography of azilsartan medoxomil, with the goal of developing an environmentally friendly method for determining the active ingredient in finished pharmaceutical forms. The research was conducted using the Shimadzu Nexera LC-30 liquid chromatograph with a diode-array detector and a Zorbax SB-Phenyl 250×4.6 (5 µm) chromatographic column. The impact of pH on the UV spectrum was tested, and it was found that, regardless of pH, the optimal wavelength for spectrophotometric detection is about 250 nm. This indicates that the same wavelength can be used for accurate detection of azilsartan medoxomil, even with pH variations in the solution. The effect of pH on the mobile phase in the reversed-phase chromatographic mode was also studied. The retention factors were found to decrease within the selected pH values of 2,0, 4,0, and 7,0, with values of 13,0, 11,9, and 1,7, respectively. This suggests a change in the chemical properties of the molecule depending on the pH, particularly the dissociation of the molecule as pH increases. Additionally, the effect of varying the organic component content in the mobile phase was determined. When the ethanol content in the solution was varied from 50% to 80% by volume, the retention factor decreased from 11,9 to 0,8. Increasing the organic component content reduces the retention time of the compound on the column, which allows for the regulation of the retention time. It was also established that the azilsartan medoxomil molecule undergoes rapid hydrolysis, converting into azilsartan, which could affect the accuracy of measurements if the substance is not stable during the analysis. The stability of azilsartan medoxomil in environmentally friendly solvents was tested at room temperature and during refrigerated storage. The results showed that azilsartan medoxomil has sufficient stability for analysis using freshly prepared solutions when solvents like dimethyl sulfoxide or 96% ethanol are used. It was also found that analytical solutions prepared with 96% ethanol are more stable when stored at 5°C. Moreover, stability was further enhanced when absolute ethanol was used as the solvent, which is a crucial factor for improving the accuracy of the analysis. The obtained results suggest the possibility of developing an environmentally friendly chromatographic method using ethanol as a component of the mobile phase and as a solvent for sample preparation. This opens the potential for creating safer and more eco-friendly methods in pharmaceutical analysis.
Keywords: azilsartan medoxomil, liquid chromatography, ethanol, green analytical chemistry.

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