Determination of low ppm levels of dimethyl sulfate in an aqueous soluble API intermediate using liquid–liquid extraction and GC–MS

Degradation Mechanism Study for Secondary Degradants in Rosuvastatin Calcium and Determination of Degradant Acetaldehyde Using Static Headspace Gas Chromatography Coupled with Matrix Precipitation

During the development of headspace gas chromatography (HSGC) method for assessing residual solvents in rosuvastatin calcium (RSV) drug substance, acetaldehyde (AA) was detected in obtained chromatograms, with a calculated concentration of up to 226 ppm. After a series of experiments, it was established that acetaldehyde originates from matrix interference due to direct degradation of Imp-C, which is accompanied by the formation of impurity at relative retention time (RRT) 2.18, without the involvement of impurity at RRT 2.31. The thermal instability of Imp-C also results in the formation of impurity at RRT 2.31 through dehydration and decarboxylation. In addition, cyclization reaction of degradant at RRT 2.18 further resulted in the generation of impurity at RRT 2.22. The structure of these three degradants, were confirmed by liquid chromatography-mass spectrometry (LC-MS), 1D and 2D nuclear magnetic resonance (NMR) measurement. In order to minimize the said matrix interference, a simple precipitation procedure was proposed as a pretreatment to mitigate the impact of Imp-C. Subsequently, an HSGC method was developed for the simultaneous determination of the degradant AA and the other five residual solvents used in RSV synthetic process. The final method was validated concerning precision, limit of detection (LOD) and limit of quantitation (LOQ), linearity, and accuracy.

In silico toxicity assessment and trace level quantification of two genotoxic impurities in silodosin using capillary gas chromatography

A capillary gas chromatographic method using flame ionization detection was developed and validated for the trace quantification of 2-bromoethanol (2-BE) and 2-bromoethylmethanesulfonate (2-BEM) in silodosin, used in the treatment of benign prostatic hyperplasia. Chromatographic separation was performed in spilt mode using nitrogen as carrier gas on a column containing crosslinked polyethylene glycol (30 m × 0.32 mm, 0.25 µm) stationary phase modified with nitroterephthalic acid. A simple matrix precipitation strategy was implemented to eliminate the sample overload and the matrix interference problems. The developed method was linear and accurate in the concentration range of 24–3000 ppm for 2-BE and 24–300 ppm for 2-BEM with r2 ˃ 0.999 and percent recoveries greater than 90% for both the analytes. The developed method was precise for both the analytes with RSD(%) of not more than 4.5%. In silico genotoxicity and carcinogenicity potential of 2-BEM were assessed using ICH M7 principles. The developed method can be applied in the quality control laboratories of pharmaceutical industries for trace level quantification of 2-BE and 2-BEM in silodosin.

Sample Preparation for Bioanalytical and Pharmaceutical Analysis

Biological and pharmaceutical samples represent formidable challenges in sample preparation that hold important consequences for bioanalysis and genotoxic impurity quantification. This Feature will emphasize significant advances toward the development of rapid, sensitive, and selective sample preparation methods.