STEPWISE BINARY GRADIENT HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC SYSTEM FOR ROUTINE DRUG-MONITORING

Drug therapy is usually optimized by concentration measurement in pati ent serum. High-performance liquid chromatography (HPLC) is one of the most important analytical techniques used for therapeutic drug monito ring (TDM) of drugs for which no immunoassay kits are available. HPLC has been frequently used for screening purposes in toxicology, too. Th e Merck Tox Screening System (MTSS) has been developed for the identif ication of substances by a combination of gradient HPLC with diode-arr ay detection and identification with a database system. For routine TD M an isocratic HPLC system is more suitable because of shorter analysi s time, better reproducibility of retention index and better precision of results. Therefore we defined a set of methods in steps of 10% of the two MTSS eluents. Three examples are shown: Amiodarone, Indometaci ne and Thiopental. New applications to test for other substances can b e transferred to an isocratic system after a complete MTSS gradient ru n.