FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute
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AVIATION MEDICINE REPORTS

Report No: DOT/FAA/AM-96/17

Title and Subtitle: A Comprehensive Drug Screening Procedure for Urine Using HPLC, TLC, and Mass Spectroscopy

Report Date: May 1996

Authors: D. Canfield, V. White, J. Soper , and T. Kupiec

Abstract: One of the missions of the Civil Aerospace Medical Institute (CAMI), Office of Aerospace Medicine (OAM), Federal Aviation Administration (FAA), is to help assess the role of potential medical or drug related pilot impairment in aviation accidents. This requires the ability to identify a wide range of drugs and the medical conditions for which these drugs are prescribed. A single extraction screening procedure was developed to identify as many drugs as possible in urine, with minimal effort and cost. Triamterene, a diuretic, is easily identified using HPLC and TLC, whereas it can not be easily identified using standard GC Mass Spectroscopy.

On the other hand, atenolol is easily identified using HPLC and Mass Spectroscopy, but is not detected using TLC at therapeutic levels. Methadone is difficult to detect using HPLC with a photo diode array and fluorescence detector, but can easily be detected using TLC and confirmed by mass spectroscopy. Urine specimens are hydrolyzed using -glucuronidase, and the specimen is then extracted using commercially purchased TOXI-LAB A extraction tubes. After removing the TOXI-LAB organic phase, the remaining aqueous layer is washed with chloroform. The organic phase and the chloroform wash are combined, evaporated to dryness, and then reconstituted in 50L of a methanol solution. A 10L quantity of the methanol solution is then chromatographed, using HPLC with a photo diode array and fluorescence detector. The methanol solution is next analyzed using either TOXI-LAB or GC Mass Spectroscopy, depending on the compound detected using HPLC. When HPLC is negative, the extract is analyzed using the TOXI-LAB procedure. This method has proven successful in the identification of benzodiazepines (alprazolam, temazepam, diazepam, nordiazepam, and oxazepam), cardiovascular medications, antihistamines, and other drugs that could have been missed using only one of the methods listed above.

The number of positive benzodiazepines identified has increased as a result of using this new method, and the time required to complete cases has been reduced substantially. Using a single aliquot, extraction, and analysis of a urine specimen by several different methods makes it possible to screen for a wide variety of drugs. Screening for these drugs would typically require several different sample aliquots and procedures. The new procedure helps prevent false negative results, that might lead investigators in aviation accidents to the wrong conclusions. The fact that drugs can be uniquely identified by HPLC, and then confirmed using GC mass spectroscopy, reduces the time necessary to complete cases by reducing the number of aliquots needed to specifically identify the drugs present in the body.

Key Words: Screening, Drugs, Urine

No. of Pages: 13