Isolation Of Degradation Products Research Articles

Forced Degradation Products of Olmesartan Medoxomil and their In Vitro Genotoxicity Assessment by Comet Assay using HEK Cells

AbstractThis study designed to characterize major forced degradation products of Olmesartan Medoxomil (OM) and to perform genotoxicity profiling using acid, base, and hydrogen peroxide‐induced stress degradation studies. The isolation of degradation products was conducted on flash chromatography using FlashPure ECOFLEX C18 4 g column with gradient elution and diode array detection‐based fraction collection, and characterized by mass spectrometry. Three impurities (impurity‐1, 2, and 3) were identified with respective m/z values of 447.213, 461.229, and 463.208. The genotoxic potential of impurities was assessed by in silico prediction, and in vitro comet assay using HEK cells. The extent of DNA damage was analyzed using Comet Assay IV imaging software. For impurity‐1, head and tail lengths and their respective total intensities were significantly (p<0.001) larger than those of dimethyl sulfoxide (solvent) control and comparable to positive control. Other parameters such as mean grey level and total area of comet were statistically significant as compared with the solvent and positive controls. Overall, impurity‐1 was a possible genotoxic impurity and a known major degradation product in OM tablet dosage form. In silico prediction also revealed impurity‐1 as toxicity class 3, whilst impurities 2 and 3 were of toxicity class 4.

Stress Degradation Studies of Anagliptin, Development of Validated Stability Indicating Method, Degradation Kinetics Study, Identification and Isolation of Degradation Products

A gradient-specific stability indicating HPLC method was developed and validated for the determination of the antidiabetic agent anagliptin in laboratory mixtures. Reversed-phase chromatography was performed using a Shimadzu LC-20 AD pump (binary), Shimadzu PDA M-20A diode array detector, and Waters Symmetry C-18 column (150 × 4.6 mm, 3.5 µm) maintained at a column oven temperature of 40 °C with UV detection at 247 nm. A gradient program was run at flow rate of 1 mL min−1. Mobile phase A consisted of a mixture of acetate buffer(10 mm) pH 5/methanol/acetonitrile in the ratio of 90:5:5. Mobile phase B consisted of a mixture of acetate buffer (10 mm) pH 5/methanol/acetonitrile in the ratio of 50:25:25. The method was validated according International Conference of Harmonization (ICH) guidelines. Linearity was observed in the concentration range of 10–120 µg/mL with regression coefficient r2(0.999). The LOD was found to be 7.8 µg/mL and LOQ was found to be 22.68 µg/mL. Anagliptin was subjected to stresses such as acidic, alkali, oxidation, photolysis, and thermal conditions. The proposed method was validated as per ICH guidelines and was found to be accurate, precise, and specific. The drug showed significant degradation in alkaline and oxidative conditions. Alkaline and oxidative degradation followed first-order kinetics. Degradation rate constant and half-lives were determined. Degradation products in alkaline and oxidative conditions were identified by LC–MS. One major degradation product was isolated from each condition by preparative HPLC. These degradation products were characterized by 1H NMR, 13C NMR, DEPT, D2O exchange, MS/MS, HRMS, and IR techniques. From the spectral data the alkaline degradation product was characterized as 1-{2-[1-(2-methylpyrazolo[1,5-a]pyrimidine-6-carboxamido)-methyl-propan-2-yl-amino]acetyl}pyrrolidine-2-carboxamide. The oxidative degradation product was characterized as N-[2-({2-[(2S)-2-cyanopyrrolidin-1-yl]-2-oxoethyl}amino)-2-methylpropyl]-2-methylpyrazolo-[1,5-a]pyrimidine-N-oxido-6-carboxamide.

Alkaline degradation of model compounds related to beech xylan

Abstract To address the chemical behavior of beech xylan (O-acetyl-4-O-methyl-glucuronoxylan) under alkaline conditions, three model compounds, 2-O-methylxylobiose (1), aldobiouronic acid (4-O-methyl-α-D-glucopyranosyluronic acid-(1→2)-xylose, 2), and aldotriouronic acid (4-Omethyl-α-D-glucopyranosyluronic acid-(1→2)-β-D-xylopyranosyl-(1→4)-D-xylose, 3), were subjected to strong alkaline conditions equal to those used for the industrial production of viscose (18% NaOH, 43°C). Kinetics of the degradation of the model compounds were monitored by capillary electrophoresis in combination with pre-column derivatization. It was demonstrated that substitution at O-2 of the reducing xylose unit strongly retarded the alkaline degradation reactions (1 and 2). By isotopic labeling experiments and isolation of degradation products it was shown that under the pertinent conditions deprotonation at C-2 occurs, followed by epimerization to the respective lyxo derivative. Aldotriouronic acid 3 was degraded to 2 as an intermediate according to classical peeling pathways. Genuine degradation reactions and epimerization processes were distinguished.

A convenient enzymatic‐chemical method for degradation of microamounts of glucose

AbstractA convenient method for degradation of 1 micromole of glucose is described. The hexose is split enzymatically to triose phosphate. In one half of this solution glyceraldehyde‐3‐phosphate is converted enzymatically to alkali stable 3‐phosphoglycerate, in the other half, dehydroxyacetone phosphate to alkali stable glycerol‐3‐phosphate. In each sample the enzymatically unconverted triose phosphate is hydrolized by alkali to lactic acid which is oxidized by ceriumIV to acetaldehyde and carbon dioxide. Acetaldehyde is degraded further to iodo form and formic acid. The latter is oxidized to carbon dioxide.The omitting laborious chromatographic separation procedurs as well as the isolation of degradation products by two step microdiffusion in a single vessel and their trapping by reagents directly applicable for photometric quantification and measurement of radioactivity makes the procedure time saving and easily performable. These advantages compensate for the loss of 50% of glucose carbon.