Claffey D J, Stout P R, Ruth J A
University of Colorado Health Sciences Center, Molecular Toxicology and Environmental Health Sciences, Denver 80262, USA.
J Anal Toxicol. 2001 Oct;25(7):607-11. doi: 10.1093/jat/25.7.607.
To explore drug-melanin interactions, we examined the in vitro tyrosinase-mediated formation of melanin from tyrosine in the presence of the 3H-cocaine (3H-COC), 3H-flunitrazepam (3H-FLU), and 3H-nicotine (3H-NIC) at 10-100,000 ng/mL. Polymerization in the presence of 10 or 100 ng/mL of each drug resulted in almost complete drug incorporation into the melanin pellet. Only 12% (3H-NIC) to 28% (3H-FLU) of the pellet-associated radioactivity could be released upon treatment with 6 M HCl. At 1000-100,000 ng/mL, between 20 and 50% of label became melanin-associated. In each case a significant percentage of melanin-associated radioactivity was resistant to treatment with 6 M HCl. Nicotine-associated radioactivity in the polymer was subject to much greater quenching than was 3H-COC or 3H-FLU, suggesting a much tighter association with the melanin. The subsequent demonstration of a covalent adduct of a melanin intermediate and nicotine has demonstrated the utility of this polymerization system as a model for further chemical characterization of drug-melanin interactions.
为了探究药物与黑色素的相互作用，我们检测了在10 - 100,000 ng/mL的3H-可卡因（3H-COC）、3H-氟硝西泮（3H-FLU）和3H-尼古丁（3H-NIC）存在下，酪氨酸经体外酪氨酸酶介导形成黑色素的过程。在每种药物浓度为10或100 ng/mL的情况下进行聚合反应，结果几乎所有药物都掺入到黑色素沉淀中。用6 M盐酸处理后，沉淀相关放射性中只有12%（3H-NIC）至28%（3H-FLU）能够被释放出来。在1000 - 100,000 ng/mL时，20%至50%的标记物与黑色素结合。在每种情况下，相当一部分与黑色素结合的放射性对6 M盐酸处理具有抗性。聚合物中与尼古丁相关的放射性比3H-COC或3H-FLU受到的淬灭作用大得多，这表明其与黑色素的结合更为紧密。随后黑色素中间体与尼古丁共价加合物的证明，证实了这种聚合系统作为进一步化学表征药物与黑色素相互作用模型的实用性。
