159 results match your criteria: "Center for Human Toxicology[Affiliation]"

Long-term stability of abused drugs and antiabuse chemotherapeutical agents stored at -20 degrees C.

J Anal Toxicol

October 1999

Center for Human Toxicology, Department of Pharmacology and Toxicology, University of Utah, Salt Lake City 84112-9457, USA.

Stability is an important consideration in the use of specimens for accurate determination of analyte concentrations. To determine the long-term stability for analytes routinely analyzed by mass spectrometry in this laboratory, quality-control (QC) results were plotted versus time. The time required for the initial concentration to reach a specified level of deviation (i.

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Enantioselective gas chromatography-negative ion chemical ionization mass spectrometry for methylphenidate in human plasma.

J Anal Toxicol

October 1999

Center for Human Toxicology, Department of Pharmacology and Toxicology, University of Utah, Salt Lake City 84112-9457, USA.

Therapeutic doses of Ritalin, a racemic mixture of d- and l-threo-methyphenidate, result in low plasma concentrations of methylphenidate. In order to assess the safety and efficacy of methylphenidate, a sensitive analytical method is needed. A gas chromatography-negative ion chemical ionization mass spectrometry (GC-NCI-MS) assay capable of measuring both d- and l-enantiomers in human plasma was developed and validated to support clinical studies involving administration of d,l-methylphenidate.

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Detection of methadone, LAAM, and their metabolites by methadone immunoassays.

J Anal Toxicol

October 1999

Center for Human Toxicology, Department of Pharmacology and Toxicology, University of Utah, Salt Lake City 84112, USA.

l-Alpha-acetylmethadol (LAAM) was recently approved as a substitute for methadone. LAAM, methadone, and their common metabolite, methadol, are extensively N-demethylated. The structural similarities of LAAM and its metabolites to methadone suggest that they may cross-react in methadone immunoassays.

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A sensitive and specific electrospray ionization high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) method has been developed for the quantitative determination of alprazolam (AL) and alpha-hydroxyalprazolam (OH-AL) in plasma. After the addition of deuterium labeled internal standards of AL and OH-AL, plasma samples were buffered to alkaline pH and extracted with toluene/methylene chloride (7:3). Dried extract residues were reconstituted in HPLC mobile phase and injected onto a reversed-phase C18 HPLC column.

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High-performance liquid chromatography (HPLC) coupled to atmospheric pressure ionization (API) mass spectrometry (MS) has become a useful technique in the direct analysis of low concentrations of conjugated opiate metabolites. Previous methods using HPLC with traditional detection methods do not have the sensitivity to detect low concentrations of most conjugated drug metabolites. Methods using gas chromatography-mass spectrometry (GC-MS) require hydrolysis and derivatization of the sample followed by an indirect quantitation of conjugated metabolites.

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Correlation of saliva codeine concentrations with plasma concentrations after oral codeine administration.

J Anal Toxicol

October 1999

Center for Human Toxicology, University of Utah, Department of Pharmacology and Toxicology, Salt Lake City 84112, USA.

A clinical study was designed to determine if there was a predictable relationship between saliva and plasma codeine concentrations. Drug-free volunteers (n = 17) were administered a 30-mg dose of liquid codeine phosphate. Plasma and saliva specimens were collected at various times for 24 h after administration.

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Detection of nandrolone, testosterone, and their esters in rat and human hair samples.

J Anal Toxicol

October 1999

Center for Human Toxicology, Department of Pharmacology and Toxicology, University of Utah, Salt Lake City 84112, USA.

Nandrolone and testosterone are anabolic androgenic steroids occasionally abused by athletes. A sensitive, specific, and reproducible gas chromatography-mass spectrometry method for the quantitative determination of nandrolone, testosterone, and their esters in hair has been developed. The limits of quantitation of this method, based on 20 mg of hair, were 50 pg/mg for nandrolone and testosterone, 100 pg/mg for testosterone acetate, and 200 pg/mg for nandrolone-decanoate.

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A retrospective study of buprenorphine and norbuprenorphine in human hair after multiple doses.

J Anal Toxicol

October 1999

Center for Human Toxicology, Department of Pharmacology and Toxicology, University of Utah, Salt Lake City 84112, USA.

The analysis of hair has been proposed as a tool for monitoring drug-treatment compliance. This study was performed to determine if buprenorphine (BPR) and norbuprenorphine (NBPR) could be detected in human hair after controlled administration of drug and to determine if segmental analysis of hair was an accurate record of the dosing history. Subjects with dark hair (six males, six females) received 8 mg sublingual BPR for a maximum of 180 days.

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Presented are findings from a multisite laboratory evaluation comparing on-site urinalysis drug-test results to results from Syva EMIT immunoassay and gas chromatography-mass spectrometry (GC-MS). Three laboratories participated in the NHTSA-funded project. Specimens were tested for amphetamines, benzodiazepines, cocaine, cannabinoids, and opiates.

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Quantitation of cocaine in human hair: the effect of centrifugation of hair digests.

J Anal Toxicol

October 1998

Center for Human Toxicology, Department of Pharmacology and Toxicology, University of Utah, Salt Lake City 84112-9457, USA.

Hair pigmentation is a critical factor in the interpretation of the concentration of certain compounds and their metabolites incorporated into hair. Melanin is responsible for the pigmentation. The color and the melanin content of human hair samples differs over a wide range.

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The incorporation of drugs into hair: relationship of hair color and melanin concentration to phencyclidine incorporation.

J Anal Toxicol

October 1998

Center for Human Toxicology, Department of Pharmacology and Toxicology, University of Utah, Salt Lake City 84112-9457, USA.

Rodents with different hair pigmentation patterns were studied to evaluate the role of melanin in the incorporation of phencyclidine (PCP) into hair. There are two types of melanin in hair and other tissues: eumelanin, a brown-black pigment and pheomelanin, a reddish-yellow pigment. Sprague Dawley (SD; nonpigmented), Dark Agouti (DA; brown), Copenhagen (CP; brown hooded), Long Evans (LE; black hooded), and LBNF1 (deep brown) rats and Swiss-Webster (SW; nonpigmented), C57BL6 (black), and C57BL6 Ay/a (yellow) mice were administered PCP at 10 mg/kg/day for 5 days (n = 5 for each strain).

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Incorporation of drugs for the treatment of substance abuse into pigmented and nonpigmented hair.

J Pharm Sci

April 1998

Center for Human Toxicology, Department of Pharmacology and Toxicology, University of Utah, Salt Lake City 84112, USA.

Hair analysis for drugs may be useful for the long-term monitoring of recidivism and treatment compliance. L-alpha-Acetylmethadol, buprenorphine, and methadone are drugs that are used for the treatment of substance abuse. The purpose of this study was to study the relationship between dose, plasma concentration, hair concentration, and hair pigmentation for these compounds and their major metabolites in an animal model.

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This study was designed to compare results obtained from two separate on-site drug testing kits (ONTRAK TESTCUP and Abuscreen ONTRAK) with those obtained from laboratory based immunoassay and GC/MS. Abuscreen ONLINE immunoassay was used to select 250 negative samples and 100 presumptive-positive samples each for cocaine/metabolites, opiates and cannabinoids. Presumptive-positive samples were selected if the immunoassay response was > or = 300 ng/mL for cocaine/metabolites (BZE), > or = 300 ng/mL for opiates or > or = 50 ng/mL for cannabinoids (THC-COOH).

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The involvement of cytochrome P450 3A4 in the N-demethylation of L-alpha-acetylmethadol (LAAM), norLAAM, and methadone.

Drug Metab Dispos

December 1997

Center for Human Toxicology, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, USA.

The N-demethylation of LAAM, norLAAM, and methadone has been investigated in human liver microsomes and microsomes containing cDNA-expressed human P450s. Gas chromatography/mass spectrometry methods allowed detection of norLAAM and dinorLAAM formation from LAAM, dinorLAAM formation from norLAAM, and EDDP and EMDP formation from methadone. The rates of N-demethylation varied 4- to 7-fold in microsomes from four different donors with activities for LAAM and norLAAM consistently greater (5- to 14-fold) than for methadone.

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Buprenorphine is used for the management of pain and has been advocated for the treatment of opioid addiction. Therapeutic doses result in low plasma concentrations of buprenorphine. In order to assess the safety and efficacy of buprenorphine, sensitive analytical methods are needed.

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Testing for Drugs of Abuse in Hair - Experimental Observations and Indications for Future Research.

Forensic Sci Rev

June 1997

Center for Human Toxicology, Department of Pharmacology and Toxicology, University of Utah Health Science Center, Salt Lake City, UT, USA.

The testing of hair for drugs of abuse is gaining popularity primarily due to the possibility that hair concentrations of drugs will reflect drug exposure for a longer period of time than either plasma or urine. Data produced by experimental research, rather than those resulting from anecdotal observations, uncontrolled research, or irrelevant experimental models, will be more likely to prove whether this is true and to determine whether drug concentrations in hair can be accurately interpreted in relation to drug dosage. Experimental observations have established that: (a) parent drug concentrations in hair are generally greater than their metabolites; (b) chemical structure of the drug is important in determining its incorporation into hair; (c) pigmentation of hair plays an important role in determining drug incorporation.

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Dose-related distribution of codeine and its metabolites into rat hair.

Drug Metab Dispos

March 1996

Center for Human Toxicology, Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, USA.

Drugs and endogenous compounds may be incorporated into the matrix of a growing hair shaft. However, the relationship between incorporation and dose or time course of plasma concentrations is poorly defined. The purpose of this study was to compare plasma and hair concentrations of codeine and its metabolites after various doses of codeine.

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To assess the impact of alcohol and other drug use in the trucking industry, the National Transportation Safety Board, in collaboration with The National Institute on Drug Abuse investigated fatal-to-the-driver trucking accidents in eight states over a one year period. Comprehensive drug screens were performed on blood specimens collected from 168 fatally injured drivers. One or more drugs were detected in 67% of the drivers and 33% of the drivers had detectable blood concentrations of psychoactive drugs or alcohol.

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Effect of phenobarbital treatment on carbon tetrachloride-mediated cytochrome P-450 loss and diene conjugate formation.

Toxicol Lett

July 1992

Center for Human Toxicology, Department of Pharmacology and Toxicology, University of Utah College of Pharmacy, Salt Lake City.

The effect of phenobarbital treatment on the linkage between carbon tetrachloride-mediated cytochrome P-450 loss and lipid peroxidation in rat liver microsomes was studied. Male Sprague-Dawley rats, pretreated with 3 daily i.p.

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A procedure for the analysis of naltrexone and 6-beta-naltrexol in plasma and urine samples is described. The method takes advantage of the specificity of negative ion chemical ionization mass spectrometry and the resolving power of capillary column chromatography to achieve a limit of quantitation of 0.1 ng/mL.

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In vitro inhibition of mouse and rat glutathione S-transferases by di(2-ethylhexyl) phthalate, mono(2-ethylhexyl) phthalate, 2-ethylhexanol, 2-ethylhexanoic acid and clofibric acid.

Toxicol In Vitro

October 2012

Center for Human Toxicology, Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah 84112, USA.

The in vitro inhibitory response of mouse and rat liver cytosolic glutathione S-transferase (GST) activities using the substrates 1,2-dichloro-4-nitrobenzene (DCNB) and 1,2-epoxy-3-(p-nitrophenoxy)propane (ENPP) was determined for the peroxisome proliferators di(2-ethylhexyl) phthalate (DEHP), mono(2-ethylhexyl) phthalate (MEHP), 2-ethylhexanol, 2-ethylhexanoic acid and clofibric acid. MEHP was a potent inhibitor of GST activities in both species, with IC(50)s for DCNB and ENPP of 0.34 and 0.

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Urine specimens were analyzed in parallel with a new TLC method, an EMIT assay, and a reference GC/MS method. At a 9-carboxy-THC cutoff of 20 ng/mL, the TLC method correctly identified 92% of the positive urines and 97% of the negative urines. In contrast, only 63% of the urine specimens shown by GC/MS to contain greater than 20 ng/mL of 9-carboxy-THC were identified as positive by the EMIT d.

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