Development and Validation of ELISA and GC-MS Procedures for the Quantification of Dextromethorphan and its Main Metabolite Dextrorphan in Urine and Oral Fluid

Abstract

I AbstractThe development of a highly sensitive enzyme-linked immunosorbent assay and gas chromatography-mass spectrometry confirmation method for the detection of dextromethorphan and its major metabolite dextrorphan in urine and oral fluid is described. For the screening assay, the intraday precision was less than 8% for urine and less than 5% for oral fluid. The interday precision was less than 10% for both drugs in urine and oral fluid. For the confirmatory procedure, both inter-and intraday precision was less than 5% for both matrices. The detection limit for both methods was 1 ng/mL. The quantifying ions chosen from the full scan mass spectra were m/z 271 for dextromethorphan, m/z 329 for dextrorphan, and m/z 332 for tri-deuterated dextrorphan-d3. A high recovery yield (> 93%) from the Quantisal TM oral fluid collection device was achieved, and the drugs were stable in the collection device for at least 10 days at room temperature. The extracted drugs from both matrices were stable for at least 48 h while kept at room temperature. Both screening and confirmatory procedures were applied to authentic urine and oral fluid specimens obtained from volunteers following therapeutic ingestion of dextromethorphan.illicit use, referred to as "robotripping", is becoming popular among teenagers because of the ease of its availability, being a non-controlled substance. The California Poison Control System reported a 10-fold increase in DXM abuse cases from 1999 to 2004, with the median age of abusers being 16 (2). This makes it increasingly important to develop better analytical methods to easily and rapidly test for DXM usage as part of a teenage drug of abuse panel. Although urine analysis has been the preferred method of testing for drugs of abuse, oral fluid is increasingly useful matrix for drug testing because of its ease of observed collection and difficulty of adulteration.Dextromethorphan is metabolized in the liver by cytochrome P450-2D6, into three metabolites: the major metabolite dextrorphan (DXO) and two minor metabolites 3-methoxymorphinan and 3-hydroxymorphinan. In addition, some is excreted as the conjugated glucuronides (Figure 1).Both DXM and DXO act as potent blockers of the N-methyld-aspartate (NMDA) receptor. At high doses, the pharmacology of DXM is similar to that of the controlled substances phencyclidine (PCP) and ketamine. It has been found that approximately 10% of the population (depending on race) are poor metabolizers and hence are susceptible to greater toxicity due

2007 National Roadside Survey of Alcohol and Drug Use by Drivers: Drug Results

“…When consumed in high doses in recreational use, it is a CNS depressant and may have driving impairment effects at those levels. The analytical method has recently been published in Rodrigues et al (2008).…”

Semi-quantitative analysis of drugs of abuse, including tetrahydrocannabinol in hair using aqueous extraction and immunoassay

“…Applications for complex matrices such as blood [7], meconium [8], bone marrow [9] as well as the more usual oral fluid [10,11] and urine [12] have been extensively reported in the scientific literature. Here, the utility of an aqueous extraction has been applied to the analysis of drugs in hair, which includes THC for the first time.…”

Current Technologies and Considerations for Drug Bioanalysis in Oral Fluid

“…For this reason, scientific literature is prolific in analytical techniques aimed at detecting and quantitating a variety of classes of abused drugs, namely opiates [52,[60][61][62][63][64][65], cannabinoids [54,[66][67][68][69][70][71], amphetamines [21,55,[72][73][74][75][76][77], cocaine [78,79] and benzodiazepines [58,[80][81][82][83][84][85][86][87]. Other substances such as ketamine, g�hydroxybutyrate (G�B) [88,89], antibiotics [90], analgesics [91,92], antitus� sives [93], cyanides and other tobacco compounds [94][95][96], and sildenafil [97], have also been ana� have also been ana� lyzed. Oral fluid has additional relevance in the case of opiate testing, since high amounts of 6�monoacetylmorphine can be detected in oral fluid in the case of heroin consumption, as well as detectable amounts of heroin itself, and therefore heroin abuse can be easily detected [12].…”