Study On The Interactions Of Nicotinamide With Several Drugs

Intermolecular interactions play an important role in biology, chemistry, medicine and other fields. Therefore, many reports were found to devote the various studies on this interaction. In recent years, due to the advances in medical science and chemical analysis methods, a number of researchers focus on the interactions between drugs. It's known that the drugs may interact with each other after oral administration in our body. The type and site of the interactions can provide theory support for the drug selection and the disease treatment on clinic.As a vitamin B, nicotinamide also is a drug, which widely used on medicine, such as the cure of p ellagra and glossitis, etc. There are often need use different drugs during the treatment of the disease. There fore, much more attentions have been attracted on the study of the interactions between nicotinamide and ot her drugs. However, the results usually being confined to the study from the clinical medicine point, and no reports were found to focus the interactions from a chemical molecular view. Moreover, the selected drug t ypes, which have been reported, are less relatively. So it is necessary to choose different drug types to inves tigate the interactions from the microscopic view using chemical analysis methods, which would provide a theoretical basis for clinical medicine.In this thesis, choosing nicotinamide as the research object, based on the detailed study of nicotinamide and water system, we studied the interactions of nicotinamide with three drugs(dopamine hydrochloride, acetaminophen, and ascorbic acid) in aqueous solution by ultraviolet- visible spectrophotometry(UV-Vis), electrochemical cyclic voltammetry(CV), nuclear magnetic resonance spectroscopy(NMR) or quantum chemistry calculation methods, which. The results are summarized as follows:1.The interactions between nicotinamide and water were studied using UV-Vis, CV, NMR methods. According to the changes of the ultraviolet absorption curve, the oxidation and reduction potential and current of cyclic voltammetry curve, and the 1H NMR spectra of NA at different NA concentrations in aqueous solution and PBS buffer solution(pH = 7.40), it was found that hydrogen bonds formed between nicotinamide and water molecules. Quantum chemistry calculations and AIM analysis further confirms the existence of hydrogen bonds between the amide group and the nitrogen atom on the pyridine rings of NA and H2 O. In addition, the NMR results also demonstrated that when nicotinamide concentration reached a certain value, the ?-? stacking interactions between nicotinamide pyridine rings would be formed. In the thesis, all the systems we studied are in aqueous solution, so the research of this part could provide a basis for the following studies, which the interactions of nicotinamide with drugs.2.The interactions between NA and dopamine hydrochloride(DH) were studied using CV, NMR and quantum chemistry calculations in aqueous solution or PBS buffer solution. According to the changes of the cyclic voltammetry curve and the 1H NMR spectra of DH in the mixed system, it was found that there exist hydrogen bonds and ?-? stacking interactions between DH and NA. Finally, the structures of the hydrogen bond complexes formed by DH and NA were optimized by the quantum chemistry calculation.3.The interactions between NA and paracetamol(PCT) were studied using CV and NMR methods in aqueous solution and PBS buffer solution. The changes of the cyclic voltammetry curve, and the 1H NMR spectra of PCT in the mixed system demonstrated that the formation of hydrogen bonds and ?-? stacking interactions between PCT and NA. Finally, the interactions of NA and ascorbic acid(AA) were studied using the same method, and found that hydrogen bonds formed between AA and NA.