Selective solid-phase extraction of mexiletine from human serum prior to its GLC analysis

A rapid and sensitive method for the GLC determination of mexiletine in human serum is described. The liquid-liquid extraction was replaced by the solid-phase extraction procedure for sample preparation using Separcol SI C 18 cartridges. The two-step elution of the cartridges after serum application was used-first with 50% acetonitrile in water for eluting endogenous compounds from serum, then with methanol to displace purified mexiletine. The recovery by this procedure was 83.6%. This selective solid-phase extraction offers an acceptable alternative to liquid extraction, and in combination with GLC-FID analysis is suitable for clinical pharmacokinetic studies of mexiletine.