Quantification Of Related Substances Research Articles

A quality-by-design evaluated liquid chromatography method development and validation for the separation and quantification of nitroxoline and its impurities.

A novel, isocratic, sensitive, stability-indicating high-performance liquid chromatography method was developed for the separation and quantification of related substances in nitroxoline (NTL). The chromatographic separation has been achieved on Inertsil ODS-3V, (250 × 4.6mm, 5μm) at 240nm using ethylenediamine tetraacetic acid buffer and methanol in the ratio of 60:40 v/v as mobile phase. The performance of the method has been checked as per the International Conference on Harmonization guidelines for specificity, linearity, accuracy, precision, and robustness. Regression analysis showed a correlation coefficient value greater than 0.99 for NTL and its three impurities. The detection limit of impurities was in the range of 0.01% (0.05μg/mL)-0.22% (1.1μg/mL) indicating the sensitivity of the newly developed method. The accuracy of the method was established based on the recovery obtained between 94.7% and 104.1% for all the impurities. The percentage relative standard deviation obtained for the repeatability was less than 4.0% at the specification level for all impurities. Forced degradation was performed to establish the stability-indicating nature of the method and to know about the degradation products, the quality of a drug substance changes with time under the influence of stress conditions. Thus, the proposed method was validated and found to be specific, sensitive, linear, accurate, precise, reproducible, and beneficial for routine usage.

Determination and quantification of related substances and degradation products in bictegravir by full factorial design evaluated HPLC and mass spectrometry.

Determining and quantifying novel impurities and degraded impurities of a drug product is always a continuous challenge to enhancing the drug quality for patients' safety. Herein, our work deals with (i) developing a rapid, accurate, and reliable high-performance liquid chromatographic validation method to quantify the bictegravir drug (integrase inhibitors of antiretroviral drugs) and its novel related impurities at low levels, and (ii) the liquid chromatography-mass spectrometry (LC-MS) method to identify degraded impurities. Separation of bictegravir acid (impurity-I) and methyl bictegravir (impurity-II) impurities which are identified by LC-MS in the bictegravir drug was executed by developing a method and the same method performance evaluated by using full factorial design. This developed analytical technique gave a well-separated peak of bictegravir and related analytes such as bictegravir acid (impurity-I) and methyl bictegravir (impurity-II), adequate with the peak properties as per USP guidelines. The method's sensitivity and linearity are demonstrated by its detection and quantification limits at low levels with a correlation coefficient of 0.998. The method's repeatability, specificity, and accuracy suggest that this developed technique is a reliable determination strategy for the bictegravir drug substance and its related impurities (impurity-I and impurity-II) in a simple, feasible, and affordable way.

Development and Validation of Reverse Phase-Ultra Performance Liquid Chromatographic Method for Estimation of Related Substances in Febuxostat Drug Substance

A novel high speed, high resolution Reverse phase-UPLC method was developed for the quantification of related substances in Febuxostat drug substance. The separation of drug from the possible impurities was achieved on a Halo C18 column. The innovative approach of using stationary phase with sub 2 μ particles provides a comprehensive combination of selectivity and speed. 10 mM mono basic potassium phosphate buffer at pH 2.7 and acetonitrile mixture was selected as mobile phase. Flow rate and detection were kept at 0.8 mL/min and 320 nm respectively. The developed UPLC method was subjected to validation parameters. System precision, accuracy, specificity, limit of detection, limit of quantification and linearity were established as per the guidelines recommended by ICH. Stability indicating nature of the method was also performed by exposing the sample under various conditions like acid, base, peroxide and photo stability exposures. Total analysis run time 7.0 minutes indicates the speed and cost saving initiation of the developed method. Using the method one can carry out the quantitative estimation of related substances in Febuxostat drug substance, further the same method can be adopted for determination of drug substance assay also.

UPLC separation and quantification of related substances of varenicline tartrate tablet

Summary A new ultra-performance liquid chromatographic (UPLC) method has been developed and validated for quantification of substances related to varenicline tartrate, process-related and degradation products, in pharmaceutical formulations. Chromatographic separation of six impurities was performed on a reversed phase column. The method was validated for linearity, limits of detection and quantification, accuracy, precision, and selectivity. The calibration plots obtained for the six impurities were linear over the range 0.005–0.30%. The relative standard deviations (sr) of intra and inter-day experiments were less than 1.0%. The detection limits ranged between 0.002 and 0.004%, depending on the impurity. The proposed UPLC method was successfully applied to quantification of varenicline impurities in its pharmaceutical formulation.