Shover Chelsea L, Koncsol Adam J, Godvin Morgan E, Goodman-Meza David, Pardo Bryce, Poimboeuf Michelle, Molina Caitlin A, Romero Ruby, Feng Jasmine, Friedman Joseph R
Department of General Internal Medicine and Health Services Research, University of California, Los Angeles, United States.
Kirby Institute, UNSW Sydney, Australia.
medRxiv. 2025 Jun 28:2025.06.27.25330446. doi: 10.1101/2025.06.27.25330446.
The variation in purity of illicitly manufactured fentanyl has been theorized to be a key driver of overdose. However, data on the purity of illicitly manufactured fentanyl in the United States typically comes from law enforcement seizures and is rarely available at the consumer-level, which is most relevant to overdose risk.
Samples were analyzed from a community-based drug checking program operating at four geographic sites in Los Angeles County, California 2023 Q1 to 2025 Q2. Participants answered an anonymous survey about sample characteristics. Qualitative and quantitative analyses were conducted leveraging directly-observed mass spectrometry (DART-MS) and Liquid chromatography mass spectrometry (LC/MS) respectively. LC/MS quantified a panel of compounds including fentanyl and fluorofentanyl. Composite fentanyl purity was estimated by adding the percent mass of fentanyl and fluorofentanyl.
A total of 353 samples had either fentanyl, fluorofentanyl, or both, quantified. Average purity was 10.0%, SD 11.1%, range 0.1%-64.9%. Samples expected to be fentanyl (n=308) had higher average purity (10.9%) compared to those expected to be heroin (n=24, average purity=2.7%) or other drugs. Powder samples (n=318) had higher average concentration (10.8%) compared to pills (n=11, 1.4%) or tar (n=22, 3.2%). Of expected-fentanyl samples, 42.5% (n=117) had a fentanyl purity of less than 5%, while 17.5% (n=51) had purity over 20%.
We found high variation in fentanyl purity among consumer-level samples sold as fentanyl, which may explain overdose among people with opioid tolerance. Fentanyl concentration was lower among samples sold as heroin, other drugs, or in pill form, and was particularly low among expected non-opioid drugs.
据推测，非法制造的芬太尼纯度差异是过量用药的关键驱动因素。然而，美国非法制造的芬太尼纯度数据通常来自执法部门的缴获，在消费者层面很少能获取到，而这与过量用药风险最为相关。
对2023年第一季度至2025年第二季度在加利福尼亚州洛杉矶县四个地理位置开展的一项基于社区的药物检测项目中的样本进行分析。参与者就样本特征回答了一份匿名调查问卷。分别利用直接实时质谱法（DART-MS）和液相色谱质谱法（LC/MS）进行定性和定量分析。LC/MS对包括芬太尼和氟芬太尼在内的一组化合物进行了定量。通过将芬太尼和氟芬太尼的质量百分比相加来估算复合芬太尼纯度。
总共对353个含有芬太尼、氟芬太尼或两者皆有的样本进行了定量分析。平均纯度为10.0%，标准差为11.1%，范围为0.1%至64.9%。预计为芬太尼的样本（n = 308）的平均纯度（10.9%）高于预计为海洛因的样本（n = 24，平均纯度 = 2.7%）或其他药物的样本。粉末样本（n = 318）的平均浓度（10.8%）高于药丸样本（n = 11，1.4%）或焦油样本（n = 22，3.2%）。在预计为芬太尼的样本中，42.5%（n = 117）的芬太尼纯度低于5%，而17.5%（n = 51）的纯度超过20%。
我们发现，作为芬太尼出售的消费者层面样本中芬太尼纯度存在很大差异，这可能解释了对阿片类药物有耐受性的人群中的过量用药情况。在作为海洛因、其他药物或药丸形式出售的样本中芬太尼浓度较低，在预计为非阿片类药物的样本中尤其低。
