Determination of Levamisole in Urine by Gas Chromatography-Mass Spectrometry

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Journal of analytical toxicology (Impact Factor: 2.86). 10/2011; 35(8):545-50. DOI: 10.1093/anatox/35.8.545
Source: PubMed


The United States Public Health Service Substance Abuse and Mental Health Services Administration is alerting medical professionals that a substantial percentage of cocaine imported into the United States is adulterated with levamisole, a veterinary pharmaceutical that can cause blood cell disorders such as severe neutropenia and agranulocytosis. Levamisole HCl is the active ingredient in a number of veterinary drugs approved to treat worm infestations in animals. Levamisole HCl was also the active ingredient in a human drug for oral administration approved on June 18, 1990, as adjuvant treatment in combination with fluorouracil after surgical resection in patients with Duke's stage C colon cancer. This drug was withdrawn from the U.S. market around 2000, and it has not been marketed in the U.S. since then. The objective of this study was to develop a method to determine the amount of levamisole in urine samples. The procedure will be provided to state health laboratories as needed to be used in the evaluation of patients that have developed neutropenia or agranulocytosis in the setting of recent cocaine use. A gas chromatography-mass spectrometry method was validated and tested at two different laboratories, and the method limit of detection for levamisole is 1 ng/mL in urine when using a 5-mL sample. Confirmation of the stereoisomer of levamisole was done by high-performance liquid chromatography using a chiral column.

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  • Case Reports 11/2012; 2012. DOI:10.1136/bcr-2012-007319
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    ABSTRACT: Study objective: To characterize the demographic, clinical, and epidemiologic features of levamisole-associated neutropenia in cocaine or heroin users. Methods: State health departments were recruited for participation when the Centers for Disease Control and Prevention (CDC) was notified of potential cases by a clinician, a health department official, or a poison center between October 15, 2009, and May 31, 2010. A case was defined as a person with an absolute neutrophil count less than 1,000 cells/μL (or a WBC count <2,000 cells/μL) and a self-reported history or laboratory confirmation of cocaine or heroin use. Health department officials abstracted data from medical charts, attempted a patient interview, and submitted data to CDC for descriptive analysis. Results: Of the 46 potential cases reported from 6 states, half met eligibility criteria and had medical chart abstractions completed (n=23; 50%). Of these, close to half of the patients were interviewed (n=10; 43%). The average age was 44.4 years; just over half were men (n=12; 52%). The majority of patients presented to emergency departments (n=19; 83%). More than half presented with infectious illnesses (n=12; 52%), and nearly half reported active skin lesions (n=10; 44%). The majority of interview respondents used cocaine greater than 2 to 3 times a week (n=9; 90%), used cocaine more than 2 years (n=6; 60%), and preferred crack cocaine (n=6; 60%). All were unaware of exposure to levamisole through cocaine and of levamisole's inherent toxicity (n=10; 100%). Conclusion: Physicians should suspect levamisole exposure in patients using illicit drugs, cocaine in particular, who present with unexplained neutropenia. Most patients reported chronic cocaine use and were unaware of levamisole exposure. Cocaine use is more prevalent among men; however, our results identified a higher-than-expected proportion of female users with neutropenia, suggesting women may be at higher risk. Emergency physicians and practitioners are uniquely positioned to recognize these patients early during their hospital course, elucidate a history of cocaine or other drug exposure, and optimize the likelihood of confirming exposure by arranging for appropriate drug testing.
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    ABSTRACT: The antihelminthic drug Levamisole can enhance cocaine effects by conversion into the amphetamine-like drug aminorex. We describe an LC-MS method for the determination of levamisole and its metabolite aminorex in human urine. Selectivity is given, calibration curves were linear within the calibration range 2.5-250 ng/mL; limits of the method were LoD 0.51 ng/mL, LoQ 1.02 ng/mL for levamisole and LoD 0.65 ng/mL, LoQ 0.76 ng/mL for aminorex. Precision data was in accordance with the guidelines (intraday precision for aminorex ranged between 5.75 and 11.0 % for levamisole between 8.36 and 10.9 %; interday precision for levamisole 10.9-16.9 % and for aminorex 7.64-12.7 %; accuracy data for levamisole -1.96 to -14.3 % and for aminorex-11.9 to-18.5 %). The validated method was successfully applied to study the urinary excretion of levamisole after the administration of 100 mg of levamisole orally. Levamisole and aminorex could be detected in post-administration urine samples. Levamisole could be detected up to 39 h after ingestion, while aminorex was detectable up to 54 h. Maximum aminorex concentrations were 45 ng/mL urine. Further metabolites of levamisole after oral ingestion by means of liquid chromatography hybrid quadrupole time-of-flight high-resolution mass spectrometry (LC-QTOF-HRMS) were identified. Only 0.5 % of the ingested drug was quantified as unchanged levamisole in urine. Besides aminorex, five isomers of aminorex and 4 hydroxy-metabolites of aminorex or its isomers were found. Furthermore, levamisole is also hydroxylated and eliminated free or conjugated with sulfate or glucuronide into urine.
    Analytical and Bioanalytical Chemistry 02/2013; 405(12). DOI:10.1007/s00216-013-6829-x · 3.44 Impact Factor
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