RESUMO
A rapid and sensitive method using HPLC has been developed for the quantification of nicorandil (SG-75) in human plasma samples for routine bioequivalence studies. The sample preparation needs two liquid-liquid extractions, first with CH3Cl and HClO4 as denaturation reagent and second with addition of ethyl acetate and Na2CO3(aq). Detection wavelength was 256 nm. The obtained correlation coefficient for weighted linear curve in the range from 5.0 to 300 ng/ml was higher than 0.9950. The limit of quantitation (LOQ) was established at 5.0 ng/ml. The HPLC separation was accomplished on Nucleosil Phenyl (5 microm) stainless steel column within 7 min. The mixture of 0.01 M ammonium acetate buffer (pH 6.2) and acetonitrile 10:3 (v/v) was used as the mobile phase. The same separation method was examined on HPLC-MS system. Using this system, the LOQ was established at 1.0 ng/ml and the linearity was obtained in the range from 1.0 to 150 ng/ml.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Espectrometria de Massas/métodos , Nicorandil/sangue , Vasodilatadores/sangue , Acetatos , Acetonitrilas , Soluções Tampão , Estabilidade de Medicamentos , Humanos , Indicadores e Reagentes , Cinética , Nicorandil/farmacocinética , Controle de Qualidade , Sensibilidade e Especificidade , Espectrofotometria Ultravioleta , Vasodilatadores/farmacocinéticaRESUMO
DeproteinatedA. niger biomass contains several covalently bound amino acids. The most abundant are arginine, serine, and proline in molar ratio of 3:2:2. One order of magnitude less is the amount of valine, phenylalanine, leucine and glycine. On deacetylation and separation of chitosan from glucan, the main three amino acids remain bound predominantly to chitosan, whereas the hydrophobic amino acids accompany mainly glucan. The presence of arginine could be the cause of stronger basicity of fungal chitosan compared to polyglucosamine.