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.

This paper describes trivalent cobalt complexes of hydrazinecarbothioamides derived from 4-(propan-2-yl) benzaldehyde and substituted thiosemicarbazides NH2NHC(S)NHR, where R = H (1), Me (2), Et (3) or Ph (4) have been synthesized and characterized. The prepared ligands and complexes were characterized using various physicochemical techniques viz. elemental analysis, molar conductance, magnetic susceptibility measurements, IR, electronic absorption spectral studies and cyclic voltammetry. The electronic spectra in DMSO solvent and magnetic susceptibility data of complexes reveal that the complexes are diamagnetic with low spin octahedral cobalt(III) complexes. The absorption titration studies revealed that each of these complexes is an avid binder to calf thymus-DNA. The apparent binding constants are in the order of 107–108 M-1 . The nucleolytic cleavage activities of the ligands and their complexes were assayed on pUC18 plasmid DNA using gel electrophoresis in the presence and absence of H2O2. The ligands showed increased nuclease activity when administered as cobalt complexes. All the complexes behave as efficient chemical nucleases with hydrogen peroxide activation. These studies revealed that the complexes exhibit both oxidative and hydrolytic chemistry in DNA cleavage.

A simple, sensitive and accurate analytical method for related substances of Voriconazole has been developed and validated by using RP-UPLC technique. The developed analytical procedure was validated as per ICH recommendations. Analysis was performed on a HALO C18 (100 × 2.1 2.7 µ) column. 20 mM ammonium formate adjusted the pH to 4.5 with formic acid was selected as buffer. Acetonitrile was used as organic modifier in the mobile phase composition. A simple gradient was applied in the method. Flow rate of mobile phase was kept at 0.4 ml per min. Column compartment temperature was maintained at 45°C. Injection volume was set at 1 µL with an auto sampler maintained the temperature at 10°C. Detection of all the components was monitored at 254 nm by photodiode array detector. Developed method satisfies the system suitability criteria, peak integrity, and resolution for the parent drug and its related substances. The proposed method was validated for Specificity, precision, accuracy, linearity, limit of detection and quantification. Forced degradation studies were conducted to assess stability indicating nature of the method under acidic, basic, oxidative and photolytic conditions. Run time less than 7.0 minutes indicating that the method is cost effective and productive; it can be successfully applied for testing of related substances in drug substance and assay of drug substance in routine quality control analysis and stability testing.