ABSTRACT
Background:Phenol-sulfuric acid assay has been widely used for quantification of sugars in biological fluid and industry. The conventional method originally proposed by Dubois et al, was modified several times for enhancing sensitivity of assay such as substituting phenol with other chromogens, by optimizing assay conditions and by adding phenol after dehydration reaction. Both conventional and modified assays have utilized acid catalysis property of sulphuric acid but effect of adding phosphoric acid has not been studied before. Methods:The present study was conducted in Department of Biochemistry, ANIIMS, Port Blair and IGIMS, Patna. The method being developed in our study consisted of adding orthophosphoricacid to the reaction mixture before addition of sulphuric acid. The method was optimized with different amounts of orthophosphoric acid. Statistical analysis was done using SPSS and Microsoft Excel software.Results:The current study found an enhancingeffect (on sensitivity) of orthophosphoric acid in optimal concentration of 5.16 mmoles. Comparison among standard curves of methods that were compared showed that the curve was steepest for current study and average absorbance was 0.199±0.017 for conventional, 0.253±0.011 for method by Rasouli et al,and 0.290±0.013 for current study. Pooled serum analysis exhibited absorbance of 0.157±0.015 in conventional method while in modified conventional method absorbance was 0.234±0.010 and highest absorbance was observed in current study at 0.281±0.012.Conclusions:Our results suggest that orthophosphoric acid exerts a positively modifying effect on phenol sulphuric acid assay.
ABSTRACT
A rapid and precise RP-HPLC method for determination of Olmesartan medoxomil and Hydrochlorothiazide in bulk and pharmaceutical dosage forms. Olmesartan medoxomil & Hydrochlorothiazide are found to be degraded together under different set of conditions as followed according to ICH guidelines and the degradants so formed along with olmesartan & hydrochlorothiazide are separated by using INERTSIL ODS C18 3V (150 x 4.6, 5μ) using mobile phase 1ml triethanolamine in one litre water and the pH was adjusted to 2.5 with orthophosphoric acid and acetonitrile using a gradient program with a flow rate of 1ml/min, throughout the gradient program with a detection wavelength of 225nm for both the compounds with a injection volume of 10μl. The method was validated for selectivity, linearity, accuracy, robustness, precision and specificity. The results were indicating the method was selective in analysis of both olmesartan medoxomil and hydrochlorothiazide in the presence of degradation products formed under various stress conditions.
ABSTRACT
A rapid and precise RP-HPLC method for determination of Olmesartan medoxomil and Hydrochlorothiazide in bulk and pharmaceutical dosage forms. Olmesartan medoxomil & Hydrochlorothiazide are found to be degraded together under different set of conditions as followed according to ICH guidelines and the degradants so formed along with olmesartan & hydrochlorothiazide are separated by using INERTSIL ODS C18 3V (150 x 4.6, 5μ) using mobile phase 1ml triethanolamine in one litre water and the pH was adjusted to 2.5 with orthophosphoric acid and acetonitrile using a gradient program with a flow rate of 1ml/min, throughout the gradient program with a detection wavelength of 225nm for both the compounds with a injection volume of 10μl. The method was validated for selectivity, linearity, accuracy, robustness, precision and specificity. The results were indicating the method was selective in analysis of both olmesartan medoxomil and hydrochlorothiazide in the presence of degradation products formed under various stress conditions.