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Research paper thumbnail of Validated method for the simultaneous determination of Δ9-tetrahydrocannabinol (THC), 11-hydroxy-THC and 11-nor-9-carboxy-THC in human plasma using solid phase extraction and gas chromatography–mass spectrometry with positive chemical ionization

Journal of Chromatography B, 2003

A fully validated, highly sensitive and specific method for the extraction and quantification of ... more A fully validated, highly sensitive and specific method for the extraction and quantification of 9 -tetrahydrocannabinol (THC), 11-hydroxy-9 -tetrahydrocannabinol (11-OH-THC) and 11-nor-9-carboxy-9 -tetrahydrocannabinol (THCCOOH) in plasma is presented. This method incorporates Escherichia coli ␤-glucuronidase hydrolysis to cleave glucuronic acid moieties to capture total analyte concentrations, and simultaneous solid phase extraction (SPE) of the three analytes in a single eluant with separation and quantification on a bench-top positive chemical ionization (PCI) gas chromatography-mass spectrometry (GC-MS) in the selected ion monitoring (SIM) mode. Quantitation was achieved by the addition of deuterated analogues for each analyte as internal standards (IS). Limits of quantitation (LOQ) were 0.5, 0.5 and 1.0 for THC, 11-OH-THC and THCCOOH, respectively, with linearity ranging up to 50 ng/ml for THC and 11-OH-THC, and 100 ng/ml for THCCOOH. Absolute recoveries ranged from 67.3 to 83.5% for all three analytes. Intra-assay accuracy and precision ranged from 1.2 to 12.2 and 1.4 to 4.7%, respectively. Inter-assay accuracy and precision ranged from 1.4 to 12.2 and 3.1 to 7.3%, respectively. This method was used to analyze plasma samples collected from individuals participating in a controlled oral THC administration study. Statistically significant (P ≤ 0.05) increases of 40% for 11-OH-THC and 42% for THCCOOH concentrations were found between hydrolyzed and non-hydrolyzed results. This method will be utilized in ongoing controlled cannabinoid administration studies and may be a useful analytical procedure for the fields of forensic toxicology and cannabinoid pharmacology.

Research paper thumbnail of Excretion of Methamphetamine and Amphetamine in Human Sweat Following Controlled Oral Methamphetamine Administration

BACKGROUND: Understanding methamphetamine (MAMP) and amphetamine (AMP) excretion in sweat is impo... more BACKGROUND: Understanding methamphetamine (MAMP) and amphetamine (AMP) excretion in sweat is important for interpreting sweat and hair testing results in judicial, workplace, and drug treatment settings.

Research paper thumbnail of Validated method for the simultaneous determination of Δ9-tetrahydrocannabinol (THC), 11-hydroxy-THC and 11-nor-9-carboxy-THC in human plasma using solid phase extraction and gas chromatography–mass spectrometry with positive chemical ionization

Journal of Chromatography B, 2003

A fully validated, highly sensitive and specific method for the extraction and quantification of ... more A fully validated, highly sensitive and specific method for the extraction and quantification of 9 -tetrahydrocannabinol (THC), 11-hydroxy-9 -tetrahydrocannabinol (11-OH-THC) and 11-nor-9-carboxy-9 -tetrahydrocannabinol (THCCOOH) in plasma is presented. This method incorporates Escherichia coli ␤-glucuronidase hydrolysis to cleave glucuronic acid moieties to capture total analyte concentrations, and simultaneous solid phase extraction (SPE) of the three analytes in a single eluant with separation and quantification on a bench-top positive chemical ionization (PCI) gas chromatography-mass spectrometry (GC-MS) in the selected ion monitoring (SIM) mode. Quantitation was achieved by the addition of deuterated analogues for each analyte as internal standards (IS). Limits of quantitation (LOQ) were 0.5, 0.5 and 1.0 for THC, 11-OH-THC and THCCOOH, respectively, with linearity ranging up to 50 ng/ml for THC and 11-OH-THC, and 100 ng/ml for THCCOOH. Absolute recoveries ranged from 67.3 to 83.5% for all three analytes. Intra-assay accuracy and precision ranged from 1.2 to 12.2 and 1.4 to 4.7%, respectively. Inter-assay accuracy and precision ranged from 1.4 to 12.2 and 3.1 to 7.3%, respectively. This method was used to analyze plasma samples collected from individuals participating in a controlled oral THC administration study. Statistically significant (P ≤ 0.05) increases of 40% for 11-OH-THC and 42% for THCCOOH concentrations were found between hydrolyzed and non-hydrolyzed results. This method will be utilized in ongoing controlled cannabinoid administration studies and may be a useful analytical procedure for the fields of forensic toxicology and cannabinoid pharmacology.

Research paper thumbnail of Excretion of Methamphetamine and Amphetamine in Human Sweat Following Controlled Oral Methamphetamine Administration

BACKGROUND: Understanding methamphetamine (MAMP) and amphetamine (AMP) excretion in sweat is impo... more BACKGROUND: Understanding methamphetamine (MAMP) and amphetamine (AMP) excretion in sweat is important for interpreting sweat and hair testing results in judicial, workplace, and drug treatment settings.

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