Determination of volume of distribution for ethanol in male and female subjects.

Ten nonalcoholic subjects gave written informed consent. Six men (aged 25-43) and four women (aged 25-35) were hydrostatically weighed to determine their percentage of body fat and lean weight. Each subject fasted for at least 10 h and then received an oral dose of alcohol (0.9 g per kilogram of lead body weight) calculated to yield a peak alcohol concentration of 0.100 g/210-L breath. Breath alcohol measurements were conducted at 20-min intervals until each subject's alcohol concentration returned to 0.000 g/210-L breath. All alcohol analyses were conducted on the Intoxilyzer 5000 and reported as g/210-L breath. Female subjects on average reached a lower peak alcohol concentration (mean, 0.086; range, 0.074-0.091 g/210 L) than male subjects (mean, 0.096; range, 0.093-0.101 g/210 L). Females demonstrated a higher average rate of elimination (mean, 0.017; range, 0.014-0.021 g/210 L) than males (mean, 0.015; range, 0.013-0.017 g/210 L). Female subjects on average had a higher percentage of body fat (mean, 26.0; range, 16.7-36.8%) than males (mean, 18.0; range, 10.2-25.3%). The average volume of distribution (Vd), as calculated from percentage of body fat, for the women (mean, 0.63; range, 0.54-0.71) was less than for the men (mean, 0.69; range, 0.63-0.76). The average Vd as calculated from linear regression of the alcohol concentration curve, for the women (mean 0.64, range, 0.56-0.71) was also less than for the men (mean, 0.72; range, 0.67-0.77). The data from this limited study indicate that hydrostatic weighing is an acceptable way of determining Vd for both men and women.

The response of the Intoxilyzer 4011AS-A to a number of possible interfering substances.

Five Intoxilyzer 4011AS-As were tested for their response to eleven chemicals and one mixture of chemicals. The air/water partition ratios were also determined for these eleven chemicals and one mixture. The chemicals tested and their approximate partition ratios were the following: acetaldehyde (190:1), acetone (341:1), acetonitrile (578:1), isoprene (1:1), isopropanol (1671:1), methanol (3229:1), methylene chloride (11:1), methyl ethyl ketone (229:1), toluene (5.5:1), 1,1,1-trichloroethane (14:1), trichloroethylene (20:1), and a 50:50 mixture of 1,1,1-trichloroethane and trichloroethylene (14:1). Of the eleven chemicals and one mixture studied during this experiment, only three, isopropanol, toluene, and methyl ethyl ketone, could reasonably interfere with the test, and then only under unusual circumstances--those circumstances being a slight additive effect to a breath ethanol concentration near the level required for prosecution. Any substantial additive effect from these three substances would illuminate the interference light which invalidates the test. The mean illumination point of the interference light was 0.0286 g/210 L for methyl ethyl ketone, 0.0294 for toluene, and between 0.0116 and 0.0292 for the apparent alcohol concentration for isopropanol, depending on the amount of isopropanol metabolized to acetone. Even with these unusual circumstances considered, the Intoxilyzer 4011AS-A must be viewed as an effective way of determining the ethanol concentration in human breath for evidential purposes.