Studies Of The Applications Of Facile NMR In Pharmacy

This paper illustrates the use of a non-deuterated reagents, do not lock field shimming direct a new method for detecting compounds-facile NMR spectra. Using a facile NMR, spectroscopy of H, C and F to investigate some of its fluorine relatively simple compounds on qualitative or quantitative analysis applications in the pharmaceutical aspects. The study found that this is not only accurate and reliable means of detection, but also practical. The main contents are as follows:(1) The facile H NMR study on the analysis of HCl concentration, and on the quantitative analysis of CH3CN in the azeotropic composition of CH3CN-H2O.For the study on HCl concentration, certain work have been put to obtain satisfactory signals in the facile H NMR detection, which contained the use of standard locking and shimming values, the use of parameters of standard spectrum of ethylbenzene; and the retrieve of good shim value from known spectrum by inputting "load=’y"’. The experiments indicated that certain relationship between the chemical shift and HCl concentration. The chemical shifts of concentrated HCl (12mol·L-1) was detected to be7.29ppm. Standard curve of HCl was obtained from Origin software by plotting the HCl chemical shifts versus concentrations. Good straight line was obtained with excellent degree of fitting (r=0.9999). Concentrations of unknown HCl solutions were determined conveniently by applying the standard curve. It was detected that the concentration of old HCl was about11mol·L-1, not1mol·L-1as predicted. The evaporation kinetic experiments of HCl in open flask at25℃and50℃showed that it took1month and1week, respectively, to reach7mol·L-1, seemedto be the most stable concentration of HCl.For the azeotropic composition analysis of CH3CN-H2O, the facile H NMR detection proved to be possible and quite convenient by comparing with other techniques. By applying the standard values of shimming and locking, satisfactory proton signals can be obtained. With the help of internal standard of capillary tube of benzene, the standard curve of CH3CH was obtained by plotting the integration versus concentration, which gave straight ling and excellent degree of good fitting (r=0.9995). The azeotropic composition of CH3CN-H2O in simple distillation, Vigreux distillation, stainless steel ring-packing distillation was77.96%,81.21%and83.75%(w/w), respectively. More CH3CN composition in azeotrope was observed with better distillation apparatus. The deuterium containing solutions of CH3CN-D2O, CD3CN-H2O, CD3CN-D2O gave azeotropic composition of74.38%-79.55%,89.03%-98.87%,89.6%-96.32%(simple distillation-Vigreux distillation), respectively. Better distillation apparatus and deuterium content significantly increase the composition of acetonitrile.(2) The facile13C NMR technique:studies on the chemical-physical properties of formaldehyde, acetaldehyde, propylaldehyde and on the analysis of ethanol. The facile C NMR were easily conducted to explore the solutions of aldehydes in aqueous or organic solvents. The spectra were carefully analyzed and useful information come out by analyzing the carbon signals and its relative integration. The studies of aqueous formaldehyde, solid paraformaldehyde, aqueous acetaldehyde, liquid propylaldehyde were performed. The reactions weith various solvents, the reactions in water, alcohol and amine was further investigated. Several unexpected resulted and signifncant information were noted.The studies of the use of facile13C NMR technique on ethanol analysis was achieved by making the standard curve, which was made available by using capillary tube internal standard of benzene. Standard curve was obtained with good straight line and good degree of fitting. The curve was applied nicely to verify the ethanol composition in several wines.(3) The use of F NMR for the qualitative and quantitative analyses of penfluridol:All the signals in H, C and F spectra were assigned in detailed and discussed. It was suggested that spiking technique in F NMR was used to confirm the structure for an unknown compound. Standard curve of penfluridol concentration versus integration was obtained by applying capillary tube internal standard of CF3CO2H. The composition of the pill was detected to be20.05mg of penfluridol, RSD=0.48%, this experiment method is accurate and reliable, and can be used for quantitative analysis of penfluridol. Parameter to obtain better F spectrum of penfluridol was investigated, which involed the parameters of "aig", larger "gain" value, near90degree "pw". The sensitivity was explored and the result showed the Varian-300NMR could detect the F signals of penfluridol dilute solution in chloroform of20ppm in3000scans with good parameters setting.