چکیده (انگلیسی):

A rapid and sensitive liquid chromatography tandem mass spectrometry method was established
and validated for determination of melatonin in dog plasma using desvenlafaxine
as an internal standard (IS). Plasma samples were pretreated by liquid–liquid extraction with
ethyl acetate. Chromatographic separation was carried out on a C18 column at a flow rate
of 0.2 ml/min by an isocratic mobile phase of methanol : 5 mMammonium acetate : formic
acid (40:60:0.1, v/v/v). Positive ion mode detection was performed using multiple reaction
monitoring (MRM) at m/z 233.2→174.2 for melatonin and m/z 264.2→58.2 for desvenlafaxine.
The method was linear in the concentration range of 0.020–10 ng/ml with a correlation coefficient
≥0.996.The intra- and inter-assay precision (%RSD) values were within 12.6% (LLOQ
15.2%), and accuracy (%RE) ranged from −1.8% to 5.0% (LLOQ ±16.5%).The total analysis time
was 3.0 min. The method was fully validated and successfully applied to a pharmacokinetic
study of melatonin prolonged-release tablet in Beagle dogs. The values of half-life and
Tmax were similar to the corresponding data reported before.