(1) Background: Inhalant abuse and misuse are still widespread problems. 1,1-Difluoroethane abuse is reported to be potentially fatal and to cause acute and chronic adverse health effects. Lab testing for difluoroethane is seldom done, partly because the maximum detection time (MDT) is unknown. We sought to reliably estimate the MDT of difluoroethane in blood after inhalation abuse; (2) Methods: MDT were estimated for the adult male American population using a physiologically based pharmacokinetic (PBPK) model and abuse patterns detailed by two individuals. Based on sensitivity analyses, variability in huffing pattern and body mass index was introduced in the model by Monte Carlo simulation; (3) Results: With a detection limit of 0.14 mg/L, the median MDT was estimated to be 10.5 h (5th–95th percentile 7.8–12.8 h) after the 2-h abuse scenario and 13.5 h (10.5–15.8 h) after the 6-h scenario. The ranges reflect variability in body mass index and hence amount of body fat; (4) Conclusions: Our simulations suggest that the MDT of difluoroethane in blood after abuse ranges from 7.8 to 15.8 h. Although shorter compared to many other drugs, these MDT are sufficient to allow for testing several hours after suspected intoxication in a patient.

中文翻译：

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Monte Carlo PBPK 建模估计的吸入滥用后血液中 1,1-二氟乙烷的检测时间

(1) 背景：吸入剂滥用和误用仍是普遍存在的问题。据报道，滥用 1,1-二氟乙烷可能致命，并会导致急性和慢性不利健康影响。二氟乙烷的实验室测试很少进行，部分原因是最大检测时间 (MDT) 未知。我们试图可靠地估计吸入滥用后血液中二氟乙烷的 MDT；(2) 方法：使用基于生理学的药代动力学 (PBPK) 模型和由两个人详述的滥用模式估计美国成年男性人群的 MDT。在敏感性分析的基础上，通过蒙特卡罗模拟在模型中引入了呼气模式和体重指数的可变性；(3) 结果：检测限为 0.14 mg/L，中位 MDT 估计为 10.5 h（第 5-95 个百分位数 7.8-12。8 小时）在 2 小时滥用场景之后和 13.5 小时（10.5-15.8 小时）在 6 小时场景之后。这些范围反映了体重指数的变化，因此反映了身体脂肪量的变化；(4) 结论：我们的模拟表明，滥用后血液中二氟乙烷的 MDT 范围为 7.8 至 15.8 小时。尽管与许多其他药物相比时间较短，但这些 MDT 足以在患者​​疑似中毒后数小时进行测试。