Separation and determination of norepinephrine, epinephrine and isoprinaline enantiomers by capillary electrophoresis in pharmaceutical formulation and human serum

A capillary electrophoresis method with ultraviolet (UV) detection was developed and optimized for the enantiomer separation of norepinephrine (NE), epinephrine (EP) and isoprenaline (IP) using dual cyclodextrins (CDs) of 2-hydroxypropyl-β-CD (HP-β-CD) and heptakis (2,6-di-o-methyl)-β-CD (DM-β-CD) as chiral selectors. Optimal separation was obtained using a running buffer of 50 mM phosphate containing 30 mM HP-β-CD and 5 mM DM-β-CD at pH 2.90 and a field strength of 20 kV in 45 cm × 75 μm (40 cm effective length) uncoated capillary. The UV absorbance detection was set at 205 nm. A 0.1% (w/w) polyethylene glycol or 0.1% (v/v) acetonitrile was used to enhance the detection sensitivity. There was a wide and excellent linear calibration graph for each enantiomer in the range 1.0 × 10−3 to 1.0 × 10−6 M and the detection limit (S/N = 3) was found from 8.5 × 10−7 to 9.5 × 10−7 M. The method has been applied for the determination of isoprenaline in isoprenaline hydrochloride aerosol and to the analysis of serum samples. The recoveries of NE and EP in serum and IP in drug were ranged from 90 to 110%. The relative standard deviations of all the analyte peaks were less than 2.8% for migration time and less than 4.8% for peak area.