Isolation and Characterization of Drugs of Abuse in Oral Fluid by a Novel Preconcentration Protocol

ABSTRACT

Oral fluid is an alternative matrix to blood for preliminary screening of drugs of abuse. Dried oral fluid spot may allow simple sampling, storage, transportation, and exclusion of enzymatic and hydrolytic degradation of analytes. The purpose of present study was to optimize drug extraction from oral fluid and dried samples to evaluate the determination of illicit drugs. The efficiency of extraction was assessed using pooled oral fluid spiked with amphetamine, methamphetamine, 3,4-methylenedioxy-methamphetamine, Δ⁹-tetrahydrocannabinol, cocaine, morphine, methadone, and clonazepam. The results indicate that simultaneous extraction of the drugs may be performed by ethyl acetate in the presence of sodium hydroxide. This procedure was used for dried oral fluid with pretreatment using methanol and hydrochloric acid to provide acceptable recovery values exceeding 70%. The applicability of the protocol was confirmed using oral fluid provided by subjects with recent use of illicit drugs. The results showed that drugs of abuse in oral fluid may be determined as the dried material and is a promising alternative to liquid sampling.

KEYWORDS:

• Drugs of abuse
• gas chromatography–mass spectrometry
• high-performance liquid chromatography
• oral fluid