EFFECTS OF PH AND SOLVENT ON THE FLUORESCENCE PROPERTIES OF BIOMEDICALLY IMPORTANT BENZAMIDES - APPLICATION TO DETERMINATION IN DRUGS AND IN HUMAN URINE

The fluorescence properties of five substituted benzamides, including alizapride, metoclopramide, sulpiride, sultopride and tiapride, were i nvestigated at several pH values and in various solvents (dimethyl sul foxide, ethanol, ethylene glycol, methanol, propan-2-ol, tetrahydrofur an and water), Except for alizapride, the fluorescence intensities wer e found to be higher,at acidic (1-6) than at alkaline (8-12) pH values , Using the. optimum solvent (aqueous solutions) and appropriate pH co nditions, linear spectrofluorimetric calibration curves were establish ed over a concentration range of about two orders of magnitude, with c orrelation coefficients larger than 0.996, Limits of detection were be tween land 13 ng ml(-1), depending on the compound, The method was app lied to the determination of benzamides in pharmaceutical preparations and in human urine, with recoveries ranging from 94 to 108% and from 93 to 104%, respectively.