Plasma concentrations of haloperidol and its reduced metabolite (reduced haloperidol) were investigated in cigarette smokers (N = 23) and nonsmokers (N = 27). Steady-state plasma concentrations were obtained 12 h post bedtime dose. Haloperidol and reduced haloperidol concentrations were determined by RIA. Reduced haloperidol was separated by selective succinylation and liquid chromatography. Patients were clinically assessed with the Clinical Global Impression Scale (CGIS). Smokers had significantly lower haloperidol and reduced haloperidol plasma concentrations than nonsmokers (P less than 0.01, P less than 0.05). Clearance of haloperidol was significantly greater in smokers compared to nonsmokers (P = 0.0052). CGIS assessments did not show significant differences between smokers and nonsmokers. Plasma concentrations should be carefully monitored when patients either start or stop smoking.
LITERATURE CITED standard deviation of the Monte Carlo X; may be a crude measure of the uncertainty associated with X,. It approaches the well-understood meaning as the distribution of X,• approaches normality. A reviewer suggests that a simple test should be devised to help an analyst decide if the deviation from normality in X; is sufficient to warrant using the more sophisticated Monte Carlo method over the local linearization method. One possibility is to draw the calibration curve and as in Figure 1 to lay off ordinates Y¿2 and Y¿2 at, say, 2 sy,intervals each from the mean Y¿. Reading from the curve X(Y;), X( Yt l) and X( Y¿2), the analyst has a measure of skewness of the X distribution as the difference between X(Y¿) and 1/2 [X( Y¿2) + ( ,•2)] as is shown in Figure 1. This simple test ignores the effect of the scatter of y¿ on the X distribution and hence should be used with caution when this scatter is large.
The loss of 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) from solution was studied using fluorescence polarization immunoassay (FPIA) technology and x-ray photoelectron spectroscopy (XPS). Several materials (glass, silylated glass, high density polyethylene, polypropylene, polystyrene, polymethylmethacrylate, Teflon, and Kynar) were studied along with three solvents (water, urine, and Abbott cannabinoids diluent). THC-COOH losses ranging from 0 to 9.7 ng/cm2 and concentration reductions to 46% of starting values were measured. XPS indicated the presence of fluorine-labeled THC-COOH at materials surfaces. A half-life of 10 min was calculated for THC-COOH loss from urine stored in high density polyethylene at room temperature. Sample handling losses during pipetting were determined and ranged from 1.1 to 7.9 ng per aliquot. The effects of sample volume and sample handling on the THC-COOH concentrations of controls were also investigated.
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