Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USA.
Clin Chem. 2013 Mar;59(3):519-26. doi: 10.1373/clinchem.2012.195503.
Cannabis is the illicit drug most frequently reported with impaired driving and motor vehicle accidents. Some "per se" laws make it illegal to drive with any amount of drug in the body, while others establish blood, saliva, or urine concentrations above which it is illegal to drive. The persistence of Δ(9)-tetrahydrocannabinol (THC) in chronic daily cannabis smokers' blood is unknown.
Thirty male chronic daily cannabis smokers resided on a secure research unit for up to 33 days, with daily blood collection. Samples were processed in an ice bath during sample preparation to minimize cannabinoid adsorption onto precipitant material. We quantified THC by 2-dimensional GC-MS.
Of the 30 participants, 27 were THC-positive on admission, with a median (range) concentration of 1.4 μg/L (0.3-6.3). THC decreased gradually; only 1 of 11 participants was negative at 26 days, 2 of 5 remained THC-positive (0.3 μg/L) for 30 days, and 5.0% of participants had THC ≥ 1.0 μg/L for 12 days. Median 11-hydroxy-THC concentrations were 1.1 μg/L on admission, with no results ≥ 1.0 μg/L 24 h later. 11-Nor-9-carboxy-THC (THCCOOH) detection rates were 96.7% on admission, decreasing slowly to 95.7% and 85.7% on days 8 and 22, respectively; 4 of 5 participants remained THCCOOH positive (0.6-2.7 μg/L) after 30 days, and 1 remained positive on discharge at 33 days.
Cannabinoids can be detected in blood of chronic daily cannabis smokers during a month of sustained abstinence. This is consistent with the time course of persisting neurocognitive impairment reported in recent studies.
大麻是与驾驶障碍和机动车事故相关的最常见的非法药物。一些“绝对”法律规定，体内有任何毒品就不能驾驶，而另一些法律则规定血液、唾液或尿液中的毒品浓度超过一定水平就不能驾驶。慢性每日吸食大麻者血液中 Δ(9)-四氢大麻酚（THC）的持续存在情况尚不清楚。
30 名男性慢性每日吸食大麻者在一个安全的研究单位居住，时间长达 33 天，每天采集血液样本。在样本制备过程中，将样本置于冰浴中以尽量减少大麻素吸附到沉淀材料上。我们通过二维 GC-MS 定量检测 THC。
30 名参与者中，有 27 名在入院时 THC 检测呈阳性，中位数（范围）浓度为 1.4 μg/L（0.3-6.3）。THC 逐渐下降；在 26 天时，只有 11 名参与者中 1 名呈阴性，5 名中有 2 名仍呈 THC 阳性（0.3μg/L），30 天时 5.0%的参与者有 12 天 THC≥1.0μg/L。入院时 11-羟基-THC 的中位数浓度为 1.1μg/L，24 小时后没有结果≥1.0μg/L。入院时 THCCOOH 的检测率为 96.7%，分别缓慢下降至第 8 天的 95.7%和第 22 天的 85.7%；5 名参与者中有 4 名在 30 天后仍呈 THCCOOH 阳性（0.6-2.7μg/L），1 名在 33 天出院时仍呈阳性。
在持续戒断一个月期间，可以在慢性每日吸食大麻者的血液中检测到大麻素。这与最近研究中报道的持续神经认知障碍的时间过程一致。
