RAPID ANALYSIS OF MELATONIN IN PHARMACEUTICAL TABLETS BY CAPILLARY ELECTROPHORESIS WITH UV DETECTION

Melatonin content in pharmaceutical products was quantitatively determined by capillary electrophoresis within 4 min. Sample preparation required the simple dissolution in water and filtration.An internal standard was used, a linear relationship between malatonine concentr. and R(melatonin corrected peak area/I.S. corrected area was obtained. Separations were carried out in a coated capillaries in borate running buffer. The method showed an high precision with a RSD for migration time of 0.3% for intra-day and 1.4%for inter-day measures (n=48). For the R parameter RSD was 2.9% and refers to seven consecutive runs of the same sample on the same day. Two commercially available pharmaceutical products containing melatonin were analysed. The method offers an easy and accurate routin option.