PubMed Health⌕ Search

Biomedical subjects

M A elSohly

Publications and source records attributed to M A elSohly.

At least 19 recordsLinked to original sources
PubMed1998

GC/MS analysis of m-hydroxybenzoylecgonine in urine. Forensic implication in cocaine use.

m-Hydroxybenzoylecgonine (m-OH-BE) and d3-m- hydroxybenzoylecgonine (d3-m-OH-BE) have been synthesized, and a GC/MS procedure with d3-m-OH-BE as internal standard has been developed. Among 24 human urine specimens that were positive for BE, all of them have shown detectable levels of m-OH-BE with 75% of the specimens exceeding the LoQ (5 ng/mL), compared with only 50% of the specimens containing detectable levels of EME. The presence of m-OH-BE in urine suggested that this metabolite may serve as a valuable marker of cocaine use in addition to BE and EME.

Cocaine↗
PubMed1997

A sensitive GC-MS procedure for the analysis of flunitrazepam and its metabolites in urine.

Analysis of urine specimens collected from individuals ingesting 2 and 4 mg flunitrazepam (FN) showed positive results by OnLine and OnTrak immunoassays for up to 60 h. Gas chromatographic-mass spectrometric (GC-MS) analysis of these specimens for FN, 3-OH-FN, 7-amino-FN, 7-amino-3-OH-FN, desmethyl-FN, and 3-OH-desmethyl-FN after glucuronidase treatment showed only low levels of 7-amino-FN with almost none of the other metabolites. These levels were far below the expected results based on the immunoassay data. This study reports on a GC-MS procedure for FN and the previously listed metabolites. The method is based on acid hydrolysis of the urine specimens, which converts FN and all its metabolites described previously to one of four amino-benzophenone derivatives (1-4) with oxazepam-d5 as the internal standard. Under the experimental conditions, the internal standard is converted to 2-amino-5-chloro-benzophenone-d5. The limit of detection for 7-amino-FN and 7-amino-desmethyl-FN and their 3-OH derivatives was less than 1 ng/mL. Analysis of urine specimens collected for 72-h postingestion of 1, 2, or 4 mg FN showed appreciable levels of benzophenone 3 (product of 7-amino-FN and 7-amino-3-OH-FN) and lower levels of benzophenone 4 (product of 7-amino-desmethyl-FN and 7-amino-3-OH-desmethyl-FN) with no detectable levels of benzophenones 1 and 2. The method makes it possible to confirm the presence of FN metabolites in urine at least 72-h postingestion of small doses of the drug.

Anti-Anxiety Agents↗
PubMed1997

Flunitrazepam excretion patterns using the Abuscreen OnTrak and OnLine immunoassays: comparison with GC-MS.

A study was conducted to compare the performance of the OnLine and OnTrak immunoassays for benzodiazepines with gas chromatographic-mass spectrometric (GC-MS) analysis in detecting flunitrazepam (FNP) and its metabolites in human urine. Urine was collected over a 72-h period from six individuals (four male and two female) who had taken a single oral dose of either 1 or 4 mg of FNP. The OnTrak assay was run at a 100-ng/mL cutoff of nordiazepam (NDP), and the OnLine assay was run with a standard curve from zero to 200 ng/mL of NDP with and without beta-glucuronidase treatment. Each sample was analyzed by GC-MS using FNP, 7-amino-FNP, 3-hydroxy-FNP, desmethyl-FNP, 7-amino-3-hydroxy-FNP, and desmethyl-3-hydroxy-FNP as standards with beta-glucuronidase treatment. The specimens from the 1-mg dose did not yield a positive result by immunoassay over the 72-h collection period. Specimens from the 4-mg dose did yield positive results in both immunoassays. The time of the first positive result ranged from 4 to 12 h, and the time to the last positive result ranged from 18 to 60 h. Treatment of the samples with beta-glucuronidase increased the OnLine values between 20 and 60%, but it did not appreciably increase the detection time. GC-MS analysis showed no detectable levels of FNP, 3-hydroxy-FNP, desmethyl-FNP, 7-amino-3-hydroxy-FNP, and desmethyl-3-hydroxy-FNP. However, all samples collected past time zero showed detectable levels of 7-amino-FNP (> 2 ng/mL) with peak concentrations at 12-36 h. The peak levels of 7-amino-FNP by GC-MS paralleled the peak levels of the immunoassay response. The amount of 7-amino-FNP metabolite quantitated by GC-MS, however, accounted for only 15-20% of the total immunoassay crossreactive FNP metabolites.

Administration, Oral↗
PubMed1995

Drug testing in the workplace: could a positive test for one of the mandated drugs be for reasons other than illicit use of the drug?

This manuscript reviews data available in the scientific literature relative to drug testing for the five mandated drug classes and circumstances other than abuse of the drug itself that could result in a positive test. For marijuana, passive inhalation, unknowing oral ingestion, and the use of Marinol are discussed. Data are presented on the concentration of delta9-tetrahydrocannabinol (THC) and its precursors, acid-A and acid-B, in illicit marijuana and the extent of extraction of THC in boiled (tea) or cooked products. For cocaine, passive inhalation and passive exposure issues are reviewed. For opiates, poppy seed ingestion and guidelines for exclusion of poppy seeds as a cause for a positive test are discussed. For amphetamines, issues such as the presence of other phenethylamines, l-methamphetamine (Vicks' inhalers), and other prescription drugs are discussed. Although passive inhalation of methamphetamine and phencyclidine is theoretically possible, no data were available on these issues.

Amphetamines↗
PubMed1995

Single dose parenteral hyposensitization to poison ivy urushiol in guinea pigs.

Studies were carried out in guinea pigs to evaluate the potential for single dose hyposensitization to poison ivy urushiol dermatitis. Sensitization was induced by topical application of 1 mg of poison ivy urushiol to the back of the neck. In the first series of studies, three different analogs of poison ivy urushiol were studied: 1) a mixture of pentadecyl and heptadecyl catechols (PDC/HDC), the saturated side chain analog of the natural urushiol mixture; 2) a mixture of the diacetate esters of PDC and HDC (PDC/HDC Ac), the esterified form of the saturated sidechain analogs; 3) 2-n-pentadecyl hydroquinone diacetate (HQ Ac). Each of these compounds was administered as 5 mg of the free catechol i.m. each week for three weeks. A vehicle group received only corn oil injections. Reactivity to poison ivy urushiol (PIU) challenge was evaluated in skin tests at 1 and 5 weeks post-treatment. PDC/HDC Ac induced a marked reduction in both the incidence and the severity of lesions induced by PIU at both 1 and at 5 weeks post-treatment. Other analogs were ineffective at 5 weeks post-treatment, and were less effective than PDC/HDC Ac at 1 week post-treatment. In a second series of experiments, the efficacy of PDC/HDC Ac was evaluated in both single and multiple dose regiments. One treatment group received 5 mg of PDC/HDC Ac intramuscularly each week for 4 weeks, while another treatment group received a single dose of 20 mg PDC/HDC Ac i.m. Corresponding vehicle control groups were also included. At 1 week post-treatment in the single dose group, the PDC/HDC Ac was only modestly effective, with some reduction of severity of lesions at the higher challenge doses of PIU. However, at 4 and 7 weeks post-treatment, both the incidence and the severity of the lesions at all challenge doses were reduced. In the multiple dose group, the incidence and severity of lesions are reduced at 1 week and 4 weeks post-treatment (4 weeks and 7 weeks after the initial dose) but were not significantly different from the single dose group. These findings indicate that the diacetate ester of PDC/HDC is an effective hyposensitizer to poison ivy urushiol, and that this hyposensitization can be reasonably accomplished in a single dose treatment regimen.

Animals↗
PubMed1994

Taxol content of stored fresh and dried Taxus clippings.

The taxol content of dried Taxus biomass was monitored monthly for 15 months. Intact and finely ground biomass was stored at room temperature (22 degrees-24 degrees) as well as under refrigeration (2 degrees-4 degrees). In addition, intact fresh clippings stored under refrigeration in sealed plastic bags for up to 10 weeks were evaluated for changes in taxol content. Analysis indicates that properly dried Taxus clippings can be stored either intact or powdered at room temperature or under refrigeration with no apparent loss of taxol content. The taxol content in fresh intact clippings was also stable for at least 10 weeks when stored under refrigeration.

Biomass↗
PubMed1991

Coca paste: chemical analysis and smoking experiments.

Several samples of Colombian and a sample of Peruvian coca paste were subjected to chemical analysis to ascertain the complexity of these products. A neutral and acid fraction and a basic fraction were analyzed by gas chromatography/flame ionization detection (GC/FID) and gas chromatography/mass spectrometry (GC/MS). The basic fraction was also analyzed as its trimethylsilyl (TMS) derivative. Several gasoline residue components were identified in the neutral fraction. In addition to cocaine (greater than 60% in all cases), other alkaloids were identified. Lead and manganese analyses were carried out on these samples. While all the samples contained no lead (less than 45 ppm), most of the Colombian samples contained significant amounts of manganese (greater than 5%). Preliminary smoking experiments with a Colombian coca paste sample indicated that it behaves more like free cocaine than like a cocaine sulfate salt.

Alkaloids↗
PubMed1988

Chromatographic and spectroscopic profiles of Cannabis of different origins: Part I.

High-resolution capillary gas chromatography with flame ionization detection and mass spectrometry (GC and GC/MS) and high-performance liquid chromatography (HPLC) were used to establish complex chemical profiles (chemical signatures) of Cannabis samples of known origin. Over 100 compounds could be differentiated, including noncannabinoids (terpenes, alkanes) as well as minor and major cannabinoids and their acids. A characteristic peak pattern was found within a limited number of specimens of identical origin. Correlation studies on the basis of peak area ratios [A(x)/A(i.s.)] showed the feasibility of tracing Cannabis chemically to its country of origin. Several forensic science applications for the chromatographic and spectroscopic profiles of confiscated Cannabis samples are discussed, such as detection of additives (phencyclidine), differentiation of chemotypes, and monitoring of tetrahydrocannabinol (THC) potency.

Cannabis↗
PubMed1988

Gas chromatographic/mass spectrometric analysis of morphine and codeine in human urine of poppy seed eaters.

In this study, poppy seeds were examined for a natural constituent that might serve as a maker for the seeds' ingestion as opposed to opiate abuse. Thebaine was selected as possible marker, since it was found to be a component of all poppy seeds examined and was not a natural component of different heroin samples. During the course of this investigation, a new extraction and cleanup procedure was developed for the gas chromatographic/nitrogen phosphorus detection (GC/NPD) and gas chromatographic/mass spectrometric (GC/MS) analysis of morphine and codeine in urine. A linear response, over a concentration range of 25 to 600 ng/mL, was obtained for codeine and morphine (r = 0.9982 and 0.9947, respectively). The minimum detectable level (LOD) and limit of quantitation (LOQ) for morphine were 10 and 30 ng/mL, respectively; whereas LOD and LOQ for codeine were 2 and 8 ng/mL, respectively. The coefficients of variance (CV, n = 6) for morphine and codeine analyses at the 100-ng/mL level were 13.3 and 4.6%, respectively. This procedure was used for the analysis of urine samples from five poppy seed eaters who each ingested 200 g of poppy seed cake. Results indicated that significant amounts of morphine and codeine are excreted in urine and that in all subjects, at least at one point in time, the apparent morphine concentration as determined by radioimmunoassay (RIA) analysis exceeded the cutoff value (300 ng/mL) established for screening. Thebaine was not detected in urine specimens collected following poppy seeds ingestion and thus could not be used as a marker.

Chromatography, Gas↗
PubMedDate not supplied

GC/MS analysis of phencyclidine acid metabolite in human urine.

Available methods for determining PCP use are based on the presence of the parent drug in urine. PCP, however, is very potent and is extensively metabolized; it is therefore present in urine in only small quantities. This work was undertaken to determine whether an amino acid metabolite of PCP, 5-(N-(1'-phenylcyclohexyl)amino)pentanoic acid, can be used to determine PCP use. A solid phase adsorption technique was developed to extract the amino acid metabolite from urine. Recovery averaged 93%, and subsequent GC/MS analysis was free from interference. Analysis of 67 urine samples demonstrated that the amino acid metabolite exists in human urine in significant quantities.

Gas Chromatography-Mass Spectrometry↗
PubMedDate not supplied

Poppy seed ingestion and opiates urinalysis: a closer look.

Review of scientific literature shows that ingestion of poppy seed containing products can result in a positive urinalysis test for opiates. In many cases the amount of seeds ingested is unrealistically high or is not specified. This study is designed to correlate the amount of seeds ingested with the urinary concentration of total morphine as a function of time. Two males and two females were involved in all four protocols, which were separated by at least one week. Subjects ingested one, two, or three poppy seed rolls, each containing 2 g of Australian seeds (108 micrograms morphine/g seed) in three protocols. In the fourth protocol subjects ingested two rolls per day for four consecutive days. Urine specimens were collected for 48 h after ingestion, analyzed by RIA, EMIT, and TDx, and selected samples were confirmed by GC/MS. The data show that the highest concentrations of total morphine in urine were found 3-8 h after ingestion or in the first-void samples. Of the 264 samples collected, there were only 16 specimens that exceeded 300 ng/mL by any of the methods used for analysis with only three samples exceeding 400 ng/mL by GC/MS (406, 611, and 954 ng/mL). In all cases, the total opiates level was less than 150 ng/mL 24 h after ingestion. Following these studies, one of the subjects ingested a poppy seed cake containing 15 g seed obtained from a bakery which analyzed for 169 micrograms morphine/g seed. Urine specimens were collected over 48 h, and all specimens were analyzed by GC/MS.(ABSTRACT TRUNCATED AT 250 WORDS)

Codeine↗
PubMedDate not supplied

Hexadeutero-11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid: a superior internal standard for the GC/MS analysis of delta 9-THC acid metabolite in biological specimens.

GC/MS analysis of biological specimens is believed to be the most forensically accepted method for confirming the presence of abused drugs. 11-Nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (delta 9-THC-COOH) is the major metabolite of delta 9-tetrahydrocannabinol (delta 9-THC) for which testing (including GC/MS) is directed as an indication of marijuana use. The currently available internal standard for delta 9-THC-COOH is d3-delta 9-THC-COOH, which has the deuterium atoms located on the side chain. In addition to the high cost of this compound, it suffers from a limited dynamic range of analysis, especially when the methyl derivative is used. This is because of a contribution to one of the internal standard ions (m/z 316) from a fragmentation of the natural drug which involves loss of the side chain. The new internal standard, d6-11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (d6-delta 9-THC-COOH), avoids these disadvantages. The six deuterium atoms are located on the two methyl groups of Carbon 6 in the dibenzopyran structure. The dynamic range of analysis with the new internal standard was tested between 6.25 to 1,000 ng/mL with a correlation coefficient of 0.998. Analysis of several urine specimens for delta 9-THC metabolite using both d3- and d6-internal standards showed a correlation coefficient of 0.9987.

Dronabinol↗