XAD-2 Resin Drug Extraction Methods for Biologic Samples

Abstract

The XAD-2 resin extraction procedure is rapidly becoming an important tool for both the clinical and forensic toxicology laboratory, and is used as a mass screening technique for drugs of abuse. Although different investigators use different elution solvents and techniques, the basic procedure is to adsorb drugs onto the XAD-2 resin and then elute these drugs with an appropriate organic solvent. A number of parameters are involved in obtaining good results. These include pH of sample, flow rate, type and volume of eluting solvent. These parameters can be adjusted so that maximum overall drug recoveries are obtained. Since XAD-2 extraction of human urine was introduced, the procedure was extended to all types of biologic specimens. Various elution techniques were reported, i.e., the differential elution of drugs from the resin into acid and neutral, and basic drug fractions. The techniques vary from rapid simple procedures for drugs of abuse in urine to more elaborate methods of extraction of autopsy material. The extraction procedure itself is flexible enough so as to suit the needs of almost any toxicology laboratory.