Quantitative analysis of phencyclidine and metabolites by capillary column gas chromatography

A sensitive capillary gas chromatography (GC) procedure was developed for the analysis of phencyclidine (PCP), two of its monohydroxy-metabolites, and a recently identified pentanoic acid metabolite. Two separate, but sequential, integrated extraction techniques were necessary to isolate all of the compounds from a 1.0-mL biological sample. Two GC techniques were necessary to analyze all the compounds; both methods used a capillary column and a nitrogen phosphorus detector (NPD). The first procedure permitted isolation and quantitation of PCP and two monohydroxy-metabolites. A second extraction of the biological samples permitted measurement of the pentanoic acid metabolite. The analytical methods illustrate good reproducibility based on within-day and day-to-day variation. Serum and urine samples were analyzed from a dog administered PCP to illustrate the utility of this procedure.

Phencyclidine blood protein binding: influence of protein, pH and species

We studied the influence of protein, pH and species on phencyclidine (PCP) protein binding. PCP binding to dog serum was unaffected by high concentrations of PCP and metabolites. The percentage of unbound PCP in pooled human serum and plasma specimens and pooled dog serum specimens was (mean +/- S.D.): 48.3 +/- 2.5; 42.5 +/- 1.8; and 43.3 +/- 1.9%, respectively. The percentage of unbound PCP in human serum albumin (HSA), 81.2 +/- 2.0%, was constant over the physiological HSA concentration range (3.5-5.5 g/dl). The binding of PCP to alpha 1-acid glycoprotein (alpha 1-AGP) increased with increasing alpha 1-AGP concentration (50-200 mg/dl). The binding to HSA or alpha 1-AGP separately did not account for the binding found in whole serum or plasma specimens. However, when a constant concentration of HSA (4.5 g/dl) was added to varying concentrations of alpha 1-AGP, the PCP binding increased dramatically and was similar to the binding found in human serum specimens. The association constant in the presence of both proteins (7.72 X 10(4) M-1) was 4.4 times greater than the association constant for alpha 1-AGP alone (1.74 X 10(4) M-1). This suggested an interaction between the proteins which resulted in enhanced PCP binding. The percentage of unbound PCP increased with decreasing pH in both dog serum and human serum specimens. This change could have possible effects on PCP distribution and elimination. The PCP blood to plasma ratio was 0.94 in pooled human heparinized blood and 1.25 in pooled dog heparinized blood. Neither species showed PCP concentration-dependent partitioning.

Kinetic study of smoking marijuana

Six subjects each smoked a 1% marijuana cigarette and 2 hr later smoked a second one. Plasma levels of delta-9-tetrahydrocannabinol were measured for 9 hr with a radioimmunoassay. Heart rate and self-reported "high" were measured for 2 hr after each cigarette. All three measures showed a rapid increase after the start of smoking with Cmax occurring before the end of smoking. There was a strong correlation between decrease in heart rate and plasma levels from 10 min after smoking until 120 min. All pharmacodynamic response measures returned to baseline values within approximately 2 hr.

Cytopathology and the management of early invasive cancer of the uterine cervix

This study was designed to review the effectiveness of cytopathology as it entered into the evaluation of patients with possible microinvasive or early occult carcinoma of the uterine cervix. During the 7-year period of 1971 to 1977, 39 consecutive patients were found for whom either a cytopathologic diagnosis of early invasive carcinoma had been made or suggested, or a histopathologic diagnosis of early invasive carcinoma had been made. After review, 35 patients had an ample number of cytopathologic and histopathologic materials and clinical records to be included in the study. The results of these studies have shown that when cytopathology on review predicted a lesion more severe than carcinoma in situ, it was confirmed by histopathology in more than 78% of patients (22 of 28 cases). In those patients shown by histopathology to have microinvasive or occult invasive carcinoma, the cytopathology reflected it in 87% of patients (27 of 31 cases). In the cases of histologically proved microinvasive carcinoma, the corresponding genital smears either diagnosed or suggested invasive carcinoma in 81% of cases and carcinoma in situ in 19%. From these studies it has been concluded that diagnostic cytopathology is potentially a highly reliable tool when used in conjunction with other modern diagnostic modalities to aid the decision-making in cases of probable early cancer of the uterine cervix.

Radioimmunoassay for phencyclidine (PCP) in serum

This accurate, sensitive radioimmunoassay for determining phencyclidine concentrations in serum specimens involves the use of anti-phencyclidine sera, 0.1 mL of serum specimen, an iodinated tracer, and a solid-phase separation. Phencyclidine metabolites do not show significant cross reactivity, but several phencyclidine analogs do cross react. Within-run coefficients of variation for human and dog serum ranged from 2.5 to 13% for concentrations from 2.0 to 500 micrograms/L. Day-to-day coefficients of variation for human and dog serum ranged from 4.3 to 16.7% for concentrations ranging from 2.0 to 90.0 micrograms/L. The sensitivity of the radioimmunoassay is less than 0.5 micrograms/L. Thirty serum specimens from two dogs given 1 mg of phencyclidine per kilogram body weight were analyzed by radioimmunoassay and a gas-chromatographic method. Nonparametric statistical comparison and linear regression showed that results from the two procedures correlate well (r2 = 0.952). Concentration-time data from the two dogs are presented to illustrate the utility of the radioimmunoassay for examining phencyclidine disposition.

The clinical pharmacology and dynamics of marihuana cigarette smoking

We have studied the dynamics of marihuana smoking, the plasma concentration of delta 9-tetrahydrocannabinol (THC), and the pharmacologic effects produced by the sequential smoking of two 1% marihuana cigarettes at a 2-hour interval. Three males and three females, experienced marihuana smokers, participated in the study. The results indicate that each subject smoked his or her two cigarettes at a similar rate. The THC plasma concentrations produced by the smoking of the second cigarette were slightly lower than those produced by the first cigarette. The levels of the psychologic "high" caused by the two cigarettes were similar. However, the first cigarette accelerated the heart twice as much as the second cigarette. Between males and females there were marked differences in the rate at which the cigarettes were smoked. In particular, males took more puffs, took them more often, and consumed the cigarettes more rapidly than females. The plasma concentrations of THC, the self-reported psychologic effects, and the heart rate acceleration produced by the smoking of the two cigarettes were identical between the sexes.

125I radioimmunoassay of delta-9-tetrahydrocannabinol in blood and plasma with a solid-phase second-antibody separation method

In this sensitive and specific radioimmunoassay for delta-9-tetrahydrocannabinol, an iodinated tracer with high specific activity and a solid-phase separation are used. Within-run coefficients of variation for 5.0 and 30.0 microgram/L concentrations were 7.8 and 4.2% for plasma and 14 and 10.6% for hemolyzed blood specimens, respectively. Day-to-day coefficients of variations ranged from 7.3 to 13.6% (for 7.6 to 33.0 microgram/L concentrations) for plasma and 13.4 to 18.1% (3.0 to 52.1 microgram/L) for hemolyzed blood specimens. Data for time after start of smoking of a standard THC-containing cigarette vs the concentration of delta-9-tetrahydrocannabinol in the plasma were similar to those obtained by others. Positive plasma specimens from the smoking study were analyzed by gas chromatography-mass spectrometry and by our radioimmunoassay. Nonparametric statistical comparison and linear regression (r2 = 0.972) showed that results by the two methods of analysis correlate well. The sensitivity of the assay was at least 0.3 microgram/L for plasma, 1.1 microgram/L for hemolyzed blood.

125I radioimmunoassay of delta-9-tetrahydrocannabinol in blood and plasma with a solid-phase second-antibody separation method

In this sensitive and specific radioimmunoassay for delta-9-tetrahydrocannabinol, an iodinated tracer with high specific activity and a solid-phase separation are used. Within-run coefficients of variation for 5.0 and 30.0 microgram/L concentrations were 7.8 and 4.2% for plasma and 14 and 10.6% for hemolyzed blood specimens, respectively. Day-to-day coefficients of variations ranged from 7.3 to 13.6% (for 7.6 to 33.0 microgram/L concentrations) for plasma and 13.4 to 18.1% (3.0 to 52.1 microgram/L) for hemolyzed blood specimens. Data for time after start of smoking of a standard THC-containing cigarette vs the concentration of delta-9-tetrahydrocannabinol in the plasma were similar to those obtained by others. Positive plasma specimens from the smoking study were analyzed by gas chromatography-mass spectrometry and by our radioimmunoassay. Nonparametric statistical comparison and linear regression (r2 = 0.972) showed that results by the two methods of analysis correlate well. The sensitivity of the assay was at least 0.3 microgram/L for plasma, 1.1 microgram/L for hemolyzed blood.

Relationship between plasma delta-9-tetrahydrocannabinol concentration and pharmacologic effects in man

The relationship between each of two pharmacologic effects (tachycardia and psychological "high") of delta-9-tetrahydrocannabinol (THC) and plasma THC concentration was investigated in three male and three female experienced marihuana smokers. Each subject smoked 1% THC cigarette on two occasions separated by 2 h. Heart rate and subjective psychological self-rating were determined frequently throughout the 4 h study period. Data were analyzed by calculating the area under the parameter versus time curves, constructing hysteresis plots, and calculating the decay rate constants from pharmacologic effect versus time plots. In both males and females, dose inhaled and psychological response were apparently equivalent for the first and second cigarettes. While all subjects exhibited marked tachycardia in response to the first cigarette, heart rate in both male and female subjects was not increased as markedly during the second cigarette. Interestingly, female subjects had less tachycardiac response than males during the second cigarette. Hysteresis plots revealed that both heart rate and subjective psychological effect were elicited in an effect compartment which was "deep" relative to the reference plasma compartment. The time courses of tachycardiac and psychological responses lagged behind the plasma THC concentration-time profile. Zero-order decay rate constants for subjective psychological rating did not change substantially from the first to second cigarette. This study suggest that plasma THC concentration is a poor predictor of simultaneously occurring physiological and psychological pharmacologic effects.