RESUMEN
During the process development of phenazopyridine HCl bulk drug, a potential impurity was detected in the routine impurity profiles by HPLC. Using MS-MS and multidimensional NMR techniques, the trace level impurity was unambiguously identified to be 3-phenyl-5-phenylazo-pyridine-2,6-diamine after its isolation from phenazopyridine HCl by semi-preparative HPLC. The formation of the impurity was discussed. To our knowledge, it is a novel impurity not reported elsewhere.
Asunto(s)
Anestésicos Locales/química , Cromatografía Líquida de Alta Presión/métodos , Contaminación de Medicamentos , Espectroscopía de Resonancia Magnética/métodos , Fenazopiridina/química , Espectrometría de Masas en Tándem/métodos , Guías como Asunto , Modelos Químicos , Espectrometría de Masa por Ionización de Electrospray/métodos , Espectroscopía Infrarroja por Transformada de Fourier/métodosRESUMEN
A simple and rapid reversed-phase high-performance liquid chromatographic method has been developed for the separation and simultaneous determination of related substances of mirtazapine in bulk drugs and pharmaceutical formulations. Six impurities, including one degradation product of mirtazapine, have been separated on a BDS Hypersil (4.6 x 250 mm; particle size 5 microm) column with a mobile phase consisting of 0.3% triethylamine (pH 3.0)-acetonitrile (78:22 v/v) eluted in an isocratic mode and monitored with a photo diode array detector at 215 nm. The chromatographic behavior of all the analytes was studied under variable compositions of different solvent systems, temperatures, buffer concentrations, and pH values. The method was validated in terms of accuracy, precision, and linearity. The inter- and intra-day assay precision was found to be < 0.98% [relative standard deviation; (RSD)] and the recoveries were in the range 95.54-102.22% with RSD < 2.21%. The correlation coefficients for calibration curves for mirtazapine as well as impurities were in the range of 0.9941-0.9999. The method was successfully applied to the analysis of commercial formulations and the recoveries of mirtazapine were in the range of 99.38-100.73% with < 0.52% RSD. The method is useful not only for rapid evaluation of the purity of mirtazapine, but also for the simultaneous determination of related substances in bulk drugs and pharmaceutical formulations.
Asunto(s)
Antidepresivos Tricíclicos , Cromatografía Líquida de Alta Presión/métodos , Contaminación de Medicamentos , Mianserina/análogos & derivados , Preparaciones Farmacéuticas/química , Acetonitrilos , Tampones (Química) , Contaminación de Medicamentos/prevención & control , Etilaminas , Concentración de Iones de Hidrógeno , Mianserina/análisis , Mianserina/aislamiento & purificación , Mirtazapina , Sensibilidad y Especificidad , TemperaturaRESUMEN
A micellar electrokinetic chromatographic (MEKC) method was developed for the quantification of lovastatin and simvastatin, cholesterol lowering agents in pharmaceutical dosage forms. Lovastatin and simvastatin were separated using an electrolyte system consisting of 12% acetonitrile (v/v) in 25 mM sodium borate buffer pH 9.3 containing 25 mM sodium dodecyl sulphate (SDS) with an extended light path capillary (48.5 cm x 50 microm i.d, 40 cm to detector). The method has been validated and proven to be rugged. Calibration curves were linear over the studied ranges with correlation coefficients greater than 0.996. A limit of detection of 3.2 microg/ml and a limit of quantitation of 10.6 microg/ml were estimated for both the drugs. The proposed method was found to be suitable and accurate for the determination of these drugs in commercial formulations.