High-performance thin-layer chromatography method for the quantification of quetiapine fumarate and its related genotoxic impurities using green solvents

A novel high-performance thin-layer chromatographic (HPTLC) analytical method has been developed and optimized for the quantification of quetiapine fumarate (QF) and its two genotoxic impurities in drug substance and drug product. The desired separation was achieved on 60F₂₅₄ pre-coated HPTLC plates using combination of green solvents, ethyl acetate‒ethanol‒n-heptane (5:1:4, V/V) as developing solvents. The detection wavelength used for quantification was 229 nm. QF and its two related genotoxic impurities, namely, 2-chloroaniline and 2-aminodiphenylsulfide, were well resolved from one another with retention factor values of 0.13 ± 0.02, 0.57 ± 0.02 and 0.76 ± 0.02, respectively. The optimized method was validated according to the guidelines laid down by the International Council for Harmonisation. The linearity was determined in the range of 100–600 ng/spot for QF and 10‒60 ng/spot for its two related genotoxic impurities; R² ≥ 0.993. The method exhibited precision along with good accuracy, where 0.51, 0.86 and 1.86. The percentage recoveries obtained for 2-chloroaniline and 2-aminodiphenylsulfide were 99.04‒101.04%. The developed method can be successfully used for the analysis of drug samples.

     

Development and Validation of an Analytical Method for the Identification of 2-Nitrophenyl(phenyl)sulfane as Potential Genotoxic Impurity of Quetiapine Fumarate at Trace Levels by High-Performance Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - Genotoxic impurities can be described as impurities that can induce genetic mutations and chromosomal breaks, or that damage the...     

High-performance thin-layer chromatography-based method development for the analysis of 4-methoxy-2-nitroaniline as potential genotoxic impurity

JPC – Journal of Planar Chromatography – Modern TLC - Omeprazole contains benzimidazole substitute, and it acts as a proton-pump inhibitor used for gastroduodenal ulcers....     

Fractal fluctuations in cardiac time series

Human heart rate, controlled by complex feedback mechanisms, is a vital index of systematic circulation. However, it has been shown that beat-to-beat values of heart rate fluctuate continually over a wide range of time scales. Herein we use the relative dispersion, the ratio of the standard deviation to the mean, to show, by systematically aggregating the data, that the correlation in the beat-to-beat cardiac time series is a modulated inverse power law. This scaling property indicates the existence of long-time memory in the underlying cardiac control process and supports the conclusion that heart rate variability is a temporal fractal. We argue that the cardiac control system has allometric properties that enable it to respond to a dynamical environment through scaling.