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Simultaneous analysis of metformin and cyanoguanidine by capillary zone electrophoresis and its application in a stability study
Author(s) -
Doomkaew Athiporn,
Prutthiwanasan Brompoj,
Suntornsuk Leena
Publication year - 2014
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201400310
Subject(s) - capillary electrophoresis , chromatography , chemistry , degradation (telecommunications) , capillary action , hydrolysis , forced degradation , detection limit , resolution (logic) , electrophoresis , quantitative analysis (chemistry) , phosphate buffered saline , calibration curve , materials science , biochemistry , telecommunications , artificial intelligence , computer science , composite material
A capillary zone electrophoresis method was established for stability study of metformin ( MET ). MET and cyanoguanidine ( CGN ; a major degradation product) were well separated (with a resolution of 38.9) in 40 mM citrate buffer (pH 6.7) using a fused‐silica capillary with an effective length of 60 cm and an inner diameter of 50 μm, injection at 50 mbar for 5 s at 30°C with an applied voltage of 15 kV and diode array detection at 214 nm. Method validation showed good linearity ( r 2 > 0.99), precision (% RSD s < 1.98%), and accuracy (%recovery between 98.3 and 100.9%). Limits of detection and quantification were <30 and 100 μg/mL, respectively. The method was robust upon alteration of pH and voltage (% RSD s < 1.99%). Stability profiles of metformin from 11 stress conditions and the degradation kinetics could be established, using the simple capillary zone electrophoresis system. A mechanism for the degradation of MET was also proposed. MET was stable in neutral hydrolysis, but degraded under alkaline hydrolysis and oxidation. Under both conditions, CGN was quantified as the degradation product. An assay of MET in raw material and tablets showed that content of the drugs in all samples met the requirements of pharmacopeias and CGN was not detected.