Abstract
A high-frequency heating extraction method was developed for drug analysis of human nails. A nail sample was placed in a glass tube with an extraction solvent and the glass tube was sealed. A ferromagnetic alloy was spirally placed around the glass tube. By applying high-frequency for 3 min, the temperature around the glass tube rose immediately to the Curie temperature of ferromagnetic alloy. After filtration, the extraction solvent was determined by liquid chromatography/mass spectrometry. Amlodipine and caffeine were detected from a nail of a hypertension patient by using this method. The extraction amounts of amlodipine and caffeine were 3 times higher than a conventional ultrasonic irradiation extraction method (30 min). This extraction method was successfully applied and detected probucol and cilostazol from the finger nails of volunteers. These results showed applicability of this method for drug screening of nail samples. It was thought that the drugs incorporated not only on the surface, but also on the center of nails, were effectively extracted by this extraction method. The characterization of drug pharmacokinetics of nails was carried out by comparing the results from two extraction methods, because drugs on the surface layer of nails can be extracted by the ultrasonic irradiation method. Some considerations about the pathways have also been described in this paper.
