Comparison of clozapine in nail and hair of psychiatric patients determined with LC-MS/MS.

As a keratinized material, nail recently has attracting researchers' attention in the pharmaceuticals analysis. There are comparatively limited studies concerning nail's xenobiotic determination and its mechanism. This article reported the development of a sensitive, specific and reproducible LC-MS/MS method, which could be as a foundation of other studies on drug determination in nail. It can also be regarded as the first report on organic drug in mainland China. Sixteen nail samples from volunteers, who were ingested clozapine for more than nine months, are confirmed positive after being analyzed by the method. It is found that contents of clozapine in the patients' nails are above the nanogram level. Besides, a comparative study of clozapine concentration in nails and hair was made, with a result that there exists a correlation between the two materials in terms of clozapine concentration.