Fluorescence determination of azithromycin in pharmaceutical formulations by using the synchronous scanning approach after its acid derivatization.

In this present work, a fluorescence method for azithromycin (9-deoxo-9a-aza-9a-methyl-9a-homoerythromycin) determination in pharmaceutical formulations is proposed. The method is based on the synchronous fluorescence (Δλ = 30 nm, 482 nm) produced when azithromycin is derivatized in strong acidic medium (9.0 mol L(-1) HCl). The influence of the derivatization conditions (acid concentration, reaction time and temperature) was studied. Also, the possible reaction mechanism was discussed. In the optimized conditions, the method presented a limit of detection of 0.23 mg L(-1) and a limit of quantification of 0.76 mg L(-1). The developed procedure was successfully applied in the determination of azithromycin in pharmaceutical formulations.