Development of an HPLC-MS/MS Method for the Determination of Silybin in Human Plasma, Urine and Breast Tissue.

Silybin is a flavonolignan extracted from with chemopreventive activity against various cancers, including breast. This study was designed to develop an HPLC-MS/MS method for the determination of silybin in human plasma, urine and breast tissue in early breast cancer patients undergoing Siliphos supplementation, an oral silybin-phosphatidylcholine complex. The determination of silybin was carried out by liquid-liquid extraction with methyl-tert-butyl ether (MTBE); total silybin concentration was determined by treating the samples with β-glucuronidase, while for the determination of free silybin, the hydrolytic step was omitted.