Rapid determination of ciprofloxacin lactate in drugs by the Rayleigh light scattering technique

A Rayleigh light scattering technique to determine ciprofloxacin lactate (CPFL) in drugs by tetraphenylboron sodium (TPB) was developed. Ciprofloxacin lactate was found to bind B(C6H5)4(-) anion and transformed to CPFL-TPB aggregate which displayed intense Rayleigh scattering light. Effects of factors such as wavelength, acidity, stabilizers and interferents on the RLS of CPFL-TPB were investigated in detail. The RLS intensity of the CPFL-TPB suspension was obtained in acetate buffer (0.50 mol L-1, pH = 4.0). The Rayleigh scattering light intensity at the maximum RLS peak of 408 nm was linear to the concentration of ciprofloxacin lactate in the range of 8.0-20.0 mu g mL(-1) with a detection limit of 6.0 mu g mL(-1). Good results were also obtained with the recovery range of 93.68-104.06%. The method was applied to determine ciprofloxacin lactate in injections, eye drops and tablets, showing high sensitivity and accuracy compared with the high performance liquid chromatography method (HPLC) according to Chinese Pharmacopoeia.