论文部分内容阅读
The most undesirable property of dihydropyridines, from pharmaceutical point of view, is high photochemical sensitivity, which can induce molecular changes leading to decrease of therapeutic effect and even some toxic effects after i.p.administration.The photo-induced changes of nisoldipine involves the oxidation of the dihydropyridine ring to a pyridine ring and the reduction of the aromatic nitro group to nitroso group, especially in the solutions.Within the general analysis of the light (radiation) influence to the pharmacological activity of nisoldipine, the study of the structure of molecule in the crystalline state has been proceeded by recording the powder XRD spectra and by modeling the structure of degradation products by molecular-mechanical calculations.Also, the photodegradation rate constants of disappearance of nisoldipine upon illumination has been determined for raw materials and pharmaceutical dosage forms.Optimal design of pharmaceutical ingredients in a formulation, as well as a safe handling of active ingredient can minimize the risk ofphotodegradation.