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Sulfonate esters, one of the genetic impurities, have gained significant attention in recent years due to their potential to cause genetic mutations and cancer. In this study, we reported a novel on‐line column‐switching liquid chromatography method for the quantitative analysis of three p‐toluene sulfonate alkyl esters in active pharmaceutical ingredients (APIs). The sensitivity was improved by large‐volume injection. A diluting modulation‐based sampling procedure was specifically devised to mitigate the impact of solvent effects and resolve the poor stability of isopropyl p‐toluene sulfonate alkyl ester. The established method was validated in terms of linearity, sensitivity, accuracy, stability, and robustness. The limit of quantitation level was determined to be 1 ng/mL (equivalent to 1 ppm relative to 1 mg/mL API samples). Besides, the method was applied for four APIs Tosuloxacin toluene sulfonate, Lapatinib toluene sulfonate, Nirapalib toluene sulfonate, and Capecitabine. The recoveries of all target analytes in the four‐drug substances were within 89%–110%. The expanded uncertainties of the measurements ranged from 6.8% to 8.4% at a coverage level of k = 2 and a confidence level of approximately 95%. The method described in this paper was compared with other published literature, demonstrating its simplicity and ease of standardization which could be further applied in the quality control and safety assessment of drug substances. [ABSTRACT FROM AUTHOR]

A new technology based on transmission Raman spectroscopy was developed for the determination of diclofenac sodium (DS) in commercially available tablets using chemometric tools such as partial least squares (PLS). Based on multifactor orthogonal design of experiment (DOE), we established an initial model consisting of 150 handmade tablets. By adding only two commercially available tablets spectra to the initial model, it was successfully applied to the determination of the active pharmaceutical ingredient (API) of three commercially available diclofenac sodium tablets. The results showed that the relative error of content measured by TRS for three brands of tablets was less than 4% and the RSD of 20 commercially available tablets under brand of Ouyi was 0.49%. The method can ensure high accuracy and good repeatability in rapid nondestructive quantitative analysis and can be used as a new technology for quality control on production lines to monitor drugs in real time. A method was developed for the determination of diclofenac sodium (DS) in commercially available tablets by TRS with PLS. By adding only two commercially available tablets spectra to the initial model, it was successfully applied to the determination of the API of three commercially available diclofenac sodium tablets. The method can ensure high accuracy and good repeatability in rapid nondestructive quantitative analysis and can be used as a new technology for quality control on production lines to monitor drugs in real time. [ABSTRACT FROM AUTHOR]

In the title compound, C6H16N(+)·C2HCl2O2 (-), the cation exhibits non-crystallographic C 2 symmetry. In the crystal, the components are linked by N-H⋯O and C-H⋯O hydrogen bonds into chains propagating along [010].

In the title compound, C20H19N3O4S, a novel tubulin ligand active against human cancer, the dihedral angle between the pyridine ring and the carbazole ring system is 42.87 (10)°. In the crystal, the mol-ecules are held together by N-H⋯O and C-H⋯O hydrogen bonds into layers, which are assembled into a three-dimensional network via π-π stacking inter-actions between inversion-related pyridine rings, with centroid-centroid distances of 3.5101 (12) Å.

In the title structure, C(25)H(24)FN(3)O(5), a strong intra-molecular O-H⋯O hydrogen bond is present between the carb-oxy group at the 3-position and the carbonyl group at the 4-position. In the crystal, mol-ecules are held together by weak C-H⋯O, C-H⋯F and π-π [centroid-centroid distance 3.6080 (8) Å] inter-actions. The 1,4-dihydro-quinoline ring and cyclo-propyl group are not in the same plane, making an inter-planar angle of 57.52 (8)°.