RESUMEN
A liquid chromatographic method was developed for simultaneous separation of a gadolinium complex and corresponding ligand using a reversed-phase anion-exchange column. The effect of mobile phase pH, EDTA and chloride ion concentration, added to the mobile phase as counter-ions, on the elution of a metal complex and ligand were investigated. Decreasing the mobile phase pH from 9.4 to 7.4 decreased the retention time of the free ligand but had little effect on changing the retention time of the complex. Increasing the EDTA concentration of the mobile phase from 0 to 0.5 mM decreased the retention of the free ligand but had little effect on changing the retention time of the metal complex. Both the retention times of the metal complex and free ligand decreased as the chloride ion concentration was increased from 0 to 0.2 M.
Asunto(s)
Cromatografía Liquida , Gadolinio/aislamiento & purificación , Cloruros , Cromatografía por Intercambio Iónico , Ácido Edético , Gadolinio/análisis , Concentración de Iones de Hidrógeno , LigandosRESUMEN
A stability-indicating LC assay was developed for the analysis of 1,2,4-benzotriazin-3-amine 1,4-dioxide and applied to the preformulation characterization of the drug. The dissociation constants of the drug were determined using UV-vis spectrophotometry. The LC method was used to determine the aqueous stability of the drug under a variety of accelerated conditions, its solubility in a variety of pharmaceutical solvents and its octan-1-ol-water partition coefficient. The preformulation data were used to develop three prototype aqueous formulations of the drug at a concentration of 0.5 mg ml-1 in 5% Dextrose Injection USP, phosphate buffer (pH 7.4) and phosphate buffered mannitol. The 3-month stability of those formulations at room temperature was demonstrated.
Asunto(s)
Cromatografía Liquida , Fármacos Sensibilizantes a Radiaciones/química , Triazinas/química , Tampones (Química) , Estabilidad de Medicamentos , Hidrólisis , Reproducibilidad de los Resultados , Solubilidad , Espectrofotometría Ultravioleta , Temperatura , Tirapazamina , AguaRESUMEN
Problems associated with the analysis of peptides and proteins in pharmaceutical products produced by biotechnology are discussed. Analytical techniques for the determination of peptides and proteins in such products are classified into four categories: bioassays, binding assays, enzyme assays and physical/chemical methods.