A quantitative nuclear magnetic resonance spectroscopic method development and validation to determine an absolute amount of levofloxacin hemihydrate in tablet dosage form

Nuclear magnetic resonance spectroscopy is a non-invasive and non-destructive analytical tool to study the structure of organic molecules; by definition itself, nuclear magnetic resonance is a quantitative technique as the peak area is proportional to the number of nuclei. So far, limited literature has been available on qNMR application in pharmaceutical analysis. A simple, precise, universal, accurate, and specific quantitative proton nuclear magnetic resonance (qNMR) spectroscopic methodology was proposed to determine the content of levofloxacin hemihydrate in the pharmaceutical tablet dosage form. In this qNMR methodology, maleic acid was utilized as internal standard (IS) and deuterated dimethyl sulfoxide-DMSO-d6 as diluent. The resonating peak at 8.94 ppm corresponds to analyte—levofloxacin hemihydrate; moreover, the ridge at 6.20 ppm corresponds to an internal standard (IS)—maleic acid. Limit of detection (LOD) and limit of quantitation (LOQ) for levofloxacin hemihydrate were obtained as 0.052 mg/0.6 mL and 0.16 mg/0.6 mL, respectively. The correlation coefficient ( R 2 ) obtained was 1.0000. The optimized experiment was validated employing specificity, limit of detection (LOD), limit of quantitation (LOQ), precision, linearity, accuracy, solution stability, and robustness consistent with International Conference on Harmonization (ICH) guidelines. The validation results conclude that the qNMR method is intended to determine the content of levofloxacin hemihydrate in the pharmaceutical tablet dosage form.