TY - JOUR T1 - Development of a High-Throughput Brain Slice Method for Studying Drug Distribution in the Central Nervous System JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 1226 LP - 1233 DO - 10.1124/dmd.108.026377 VL - 37 IS - 6 AU - Markus Fridén AU - Frederic Ducrozet AU - Brian Middleton AU - Madeleine Antonsson AU - Ulf Bredberg AU - Margareta Hammarlund-Udenaes Y1 - 2009/06/01 UR - http://dmd.aspetjournals.org/content/37/6/1226.abstract N2 - New, more efficient methods of estimating unbound drug concentrations in the central nervous system (CNS) combine the amount of drug in whole brain tissue samples measured by conventional methods with in vitro estimates of the unbound brain volume of distribution (Vu,brain). Although the brain slice method is the most reliable in vitro method for measuring Vu,brain, it has not previously been adapted for the needs of drug discovery research. The aim of this study was to increase the throughput and optimize the experimental conditions of this method. Equilibrium of drug between the buffer and the brain slice within the 4 to 5 h of incubation is a fundamental requirement. However, it is difficult to meet this requirement for many of the extensively binding, lipophilic compounds in drug discovery programs. In this study, the dimensions of the incubation vessel and mode of stirring influenced the equilibration time, as did the amount of brain tissue per unit of buffer volume. The use of casette experiments for investigating Vu,brain in a linear drug concentration range increased the throughput of the method. The Vu,brain for the model compounds ranged from 4 to 3000 ml · g brain–1, and the sources of variability are discussed. The optimized setup of the brain slice method allows precise, robust estimation of Vu,brain for drugs with diverse properties, including highly lipophilic compounds. This is a critical step forward for the implementation of relevant measurements of CNS exposure in the drug discovery setting. The American Society for Pharmacology and Experimental Therapeutics ER -