Determination of drug reference substance content by 1H-nuclear magnetic resonance spectroscopy

This article discussed the feasibility of determining the content of reference substance by H-1-nuclear magnetic resonance spectroscopy (NMR). 9 reference substances of quinolone antibiotics were chosen as examples, such as ciprofloxacin, antofloxacin, caderofloxacin, gatifloxacin, L-ofloxacin, ofloxacin, norfloxacin, enoxacin, lomefloxacin. D2O, D-6-dimethyl sulfoxide (DMSO), or 0.3 mol/L NaOH in D2O solution was used as solvent. Hydroquinone and maleic acid were selected as internal standard. By measuring the selected proton peak intensity, the quantitative analysis of samples was achieved. The difference between the result of NMR method and labelled content was about 1%. The results came from the internal standard method were same as those of external standard one. This method is specificity, rapid, accurate, simple, and it is suitable for the quantitative determination of the reference substance content.