Abstract: This paper describes an effective method for determining ciprofloxacin lactate. An excess of sodium tetraphenylboron was added to precipitate ciprofloxacin lactate in HAc-NaAc buffer solution (pH = 4.0). After filtering off the precipitate, the excessive sodium tetraphenylboron in the filtrate was titrated with cetyltrimethylammonium bromide standard solution, with bromophenol blue as indicator. The method is simple and rapid, it has been applied to the determination of ciprofloxacin lactate raw material with satisfactory results. The recovery was between 99.66% and 100.2%, the relative error was less than ±0.40%. Experiments showed that the method gave the same results as the approach using nonaqueous titration (ChP).

Key words: Ciprofloxacin lactate, Ciprofloxacin lactate, Sodium tetraphenylboron, Sodium tetraphenylboron, Bromophenol blue, Bromophenol blue, Cetyltrimethylammonium bromide, Cetyltrimethylammonium bromide