Miolo Giorgia, Tucci Marianna, Menilli Luca, Stocchero Giulia, Vogliardi Susanna, Scrivano Salvatore, Montisci Massimo, Favretto Donata
Department of Pharmaceutical and Pharmacological Sciences, University of Padova, 35131 Padova, Italy.
Legal Medicine and Toxicology, University Hospital of Padova, 35121 Padova, Italy.
Brain Sci. 2018 May 28;8(6):96. doi: 10.3390/brainsci8060096.
Drugs incorporated into hair are exposed to the environment, and cosmetic and chemical treatments, with possible decreases in their content. Knowledge concerning the effect of sunlight on drug content in hair can be helpful to forensic toxicologists, in particular, when investigating drug concentrations above or below pre-determined cut-offs. Twenty authentic positive hair samples were selected which had previously tested positive for amphetamines and/or ketamine. Washed hair were divided into two identical strands, with the former exposed at 765 W/m² (300⁻800 nm spectrum of irradiance) for 48 h in a solar simulator, and the latter kept in the dark. Hair samples were extracted and analyzed by liquid chromatography high-resolution mass spectrometry detection. The percentage of photodegradation was calculated for each analyte (i.e., amphetamine, methamphetamine, methylendioxyamphetamine, ketamine, and norketamine). In parallel, photodegradation processes of standard molecules dissolved in aqueous and organic solutions were studied. In 20 hair samples positive for the targeted analytes, exposure to artificial sunlight induced an appreciable decrease in drug concentrations. The concentration ranges in the non-irradiated hair samples were 0.01⁻24 ng/mg, and 65% of samples exhibited a decrease in post-irradiation samples, with reduction from 3% to 100%. When more drugs were present in the same hair sample (i.e., MDMA and ketamine) the degradation yields were compound dependent. A degradation product induced by irradiation of ketamine in aqueous and methanol solutions was identified; it was also found to be present in a true positive hair sample after irradiation. Ketamine, amphetamines, and their metabolites incorporated in the hair of drug users undergo degradation when irradiated by artificial sunlight. Only for ketamine was a photoproduct identified in irradiated standard solutions and in true positive irradiated hair. When decisional cut-offs are applied to hair analysis, photodegradation must be taken into account since sunlight may produce false negative results. Moreover, new markers could be investigated as evidence of illicit drug use.
掺入头发中的药物会暴露于环境中，以及接受美容和化学处理，其含量可能会降低。了解阳光对头发中药物含量的影响，对法医毒理学家尤其有帮助，特别是在调查药物浓度高于或低于预定临界值时。选取了20份经鉴定为苯丙胺和/或氯胺酮呈阳性的真实头发样本。将洗净的头发分成两根相同的发束，前者在太阳模拟器中以765 W/m²（300⁻800 nm光谱辐照度）照射48小时，后者保存在黑暗中。头发样本通过液相色谱高分辨率质谱检测进行提取和分析。计算每种分析物（即苯丙胺、甲基苯丙胺、亚甲基二氧基苯丙胺、氯胺酮和去甲氯胺酮）的光降解百分比。同时，研究了溶解在水溶液和有机溶液中的标准分子的光降解过程。在20份目标分析物呈阳性的头发样本中，暴露于人工阳光下会导致药物浓度明显降低。未照射的头发样本中的浓度范围为0.01⁻24 ng/mg，65%的样本在照射后的样本中浓度降低，降低幅度从3%到100%。当同一头发样本中存在更多药物（即摇头丸和氯胺酮）时，降解产率取决于化合物。鉴定出了氯胺酮在水溶液和甲醇溶液中照射产生的降解产物；在照射后的真实阳性头发样本中也发现了该产物。吸毒者头发中掺入的氯胺酮、苯丙胺及其代谢物在人工阳光下照射时会发生降解。仅在氯胺酮的照射标准溶液和真实阳性照射头发中鉴定出了一种光产物。在对头发分析应用判定临界值时，必须考虑光降解，因为阳光可能会产生假阴性结果。此外，可以研究新的标记物作为非法药物使用的证据。
