THE SPECTROFLUORIMETRY METHOD FOR DETERMINATION OF NALIDIXIC ACID IN HUMAN PLASMA

This paper describes a precise and sensitive method for analysis of Nalidixic Acid (NA) in plasma following the oral administration of a therapeutic dose in humans. Most procedures used for quantitation of NA are based on its fluorescence. The spectrofluorimetry is the best choice for a fluorescent drug, regarding its specificity and sensitivity of the method. Also, it is recommended for the fluorescent drug assay in pharmaceutical companies as a cheaper, more routin and time saving right way in comparison with chromatographic methods. For the practical determination, a new formulation of nalidixic acid tablet was used as a modle and compared with a work standard by invitro and invivo evalutions as a crossover study in 12 normal volunteers. The friability, weight variation, assay and dissolution test for both products were almost the same and approved by USP requirements.The plasma samples and pharmacokinetic parameters were determined. Results of the tests and their statistical analysis indicated no significant differences (P<0.05) between the products. Since the extent and rate of absorption of the new and work standard tablets are comparable and the plasma 90% confidence intervals for Cmax and Tmax ratios lie within 80-125% of their respective mean values, therefore the spectrofluorimetry is approved to be the best selection for a fluorescent drug , chemically and pharmaceutically.