EXTRACTION-SPECTROFLUOROMETRIC METHOD FOR THE DETERMINATION OF ERYTHROMYCIN AND ITS ESTERS IN PHARMACEUTICAL FORMULATIONS USING MANUAL AND FLOW-INJECTION PROCEDURES

A sensitive and rapid extraction-spectrofluorimetric method for the de termination of erythromycin, based on the formation of an ion pair wit h Erythrosine B, is described. The calibration graph resulting from th e measurement of the fluorescence of the chloroform extract (10 cm3) a t 560 nm with excitation at 544 nm is linear over the range 10-600 mug of erythromycin per 20 cm3 of total volume of aqueous phase, with a r elative standard deviation (RSD) of 1.5% for 3.7 mug cm-3 erythromycin . The method can be successfully adapted to an unsegmented flow system , the peak height being proportional to erythromycin concentration ove r the range 0.65-5.88 mug of erythromycin per 400 mm3 of sample soluti on injected. Up to 45 samples h-1 can be processed with an RSD of 2.9- 3.8%. Manual and flow-injection methods were satisfactorily applied to the determination of erythromycin in pharmaceutical preparations.