A cannabis smoking trial was conducted using paid volunteers. Subjective intoxication, measured using a visual analogue scale, was compared with heart rate and with salivary delta-9-tetrahydrocannabinol (THC) levels at various times after smoking a cigarette containing 11 mg THC. Subjective intoxication and heart rate elevation were significantly correlated with the log of salivary THC. Salivary THC levels are a sensitive index of recent cannabis smoking, and appear more closely linked with the effects of intoxication than do either blood or urine cannabinoid levels.
A rapid method for determining paracetamol (acetaminophen) in whole blood and liver tissue samples is described. Blank plus single-point calibration gives reliable quantitation at therapeutic and higher concentrations. Whole blood and liver tissue samples containing a deuterated internal standard were extracted using Bond Elut Certify columns. Butyl derivatives were formed using n-iodobutane and tetramethyl ammonium hydroxide under mild conditions and were extracted into ethyl acetate as a cleanup step. Recovery was better than 90%, and sample preparation time was less than 2 h. Gas chromatograph run time was less than 20 min. SIM of two ion pairs formed by electron impact ionization resulted in intraday coefficients of variation (CV) less than 3.03% (7.48% in liver) and interday CVs less than 8.93% (for midtherapeutic concentrations in whole blood). Linearity was observed from subtherapeutic to high, fatal levels. This method has been applied to forensic cases and has significantly reduced analytical time while improving casework quality. Results of a case study involving paracetamol are given.
A rapid method for simultaneously determining the anticonvulsant drugs carbamazepine, ethosuximide, phenobarbitone, phenytoin, primidone, and valproic acid is described. Blank plus single-point calibration gives reliable quantitation from therapeutic to high fatal concentrations, except for ethosuximide, for which it gives semiquantitative results. Whole blood and liver tissue samples containing deuterated internal standards were extracted using Bond Elut Certify columns. Butyl derivatives were formed using n-iodobutane and TMAH under mild conditions and were extracted into ethyl acetate as a cleanup step. Recoveries were greater than 50%, except for valproic acid (42%). Sample preparation time was less than 2 h, and the GC run time was less than 20 min per injection. At least two ion pairs formed by electron impact ionization were monitored for each drug. Intraday CVs were less than 6.28% (4.20%) and interday CVs less than 14.1% (for midtherapeutic concentrations in blood [liver], except for ethosuximide). Linearity was observed from subtherapeutic to high fatal levels for all drugs. This method has been applied to forensic cases and has significantly reduced analytical time while improving case-work quality. Results of a case study involving anticonvulsant drugs are given.
This report describes sensitive and specific methods for the quantitation of alprazolam and triazolam in hemolysed whole blood and liver tissue. Samples of blood and enzyme-digested liver are extracted without pH adjustment with n-butyl chloride, after addition of deuterated internal standards and urea. The evaporated extracts are reconstituted in acetonitrile for analysis by gas chromatography/mass spectrometry/negative ion chemical ionization (GC/MS/NICI). Fatty extracts may be cleaned up by partitioning between pentane and acetonitrile. Two ion pairs are monitored for each drug. Within-day coefficients of variation in the range 10-50 micrograms/L for blood are approximately 5%. Between-day coefficients of variation are less than 10%. The limit of quantitation (based on analysis of 0.2-mL blood samples) is 0.5 microgram/L for triazolam and 4 micrograms/L for alprazolam.
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