QUANTITATIVE DETERMINATION OF RESIDUAL MONOMETHYLAMINE CONTENT IN NEBIVOLOL HYDROCHLORIDE BY HPIC WITH SUPPRESSED CONDUCTIVITY DETECTION.

The aim of this paper was to develop a simple analytical method which could be used to determine a synthesis-derived amount of monomethylamine (MMA) residue present in nebivolol hydrochloride. High-performance ion chromatography (HPIC) method with suppressed conductivity detection was used for this purpose. The HPIC analysis was performed with IonPac CS 14 column (250 x 4 mm) containing a macroporous weak cation-exchange stationary phase eluted with 10 mM methanesulfonic acid (MSA). Validation of the method confirmed its selectivity by achieving a satisfactory separation of alkyl- and alkanolamines and metal cations. The method also showed a sufficient precision (RSD < 5.0%) and accuracy (recovery 90-103%). The calibration plot was linear in the range 0.03-2.4 μg/mL of MMA (r² = 0.9997). The calculated limit of quan- tification LOQ was 0.03 μg/mL. Amount of the MMA contained in nebivolol hydrochloride was determined by direct reading from the calibration curve and by the multiple standard additions method. Both methods showed satisfactory precision (RSD < 10.0%) and they can be used to determine the monomethylamine content in the studied active substance.