ION-EXCHANGE LIQUID-CHROMATOGRAPHY METHOD WITH INDIRECT UV DETECTION FOR THE ASSAY OF CHOLINE IN PHARMACEUTICAL PREPARATIONS

A high-performance liquid chromatography (HPLC) method coupled with in direct UV spectrophotometric detection was developed for the routine c ontrol of pharmaceutical preparations containing choline. Optimization of the HPLC system using silica-based cation exchange columns was foc used on the combination in the mobile phase between a UV transparent c o-ion and a UV active cationic probe. The selected mobile phase consis ted of a mixture of ethanol-ammonium acetate buffer (100 mM, pH 5.0) ( 20:80, v/v) containing 0.3 mM of 3-hydroxytyramine as chromophoric pro be; UV detection was operated at 280 nm. The HPLC system provided full selectivity with regard to the multi-ingredient pharmaceutical matric es tested. Quantitative analysis was validated by testing linearity of the method between 50 and 150% of the theoretical content (coefficien t of correlation greater than 0.99) and repeatability (relative standa rd deviation less than 2.5%; n = 5).