Pearson S D, Ash K O, Urry F M
Department of Pathology, University of Utah School of Medicine, Salt Lake City 84132.
Clin Chem. 1989 Apr;35(4):636-8.
To drug-free urine specimens, we added the following drugs of abuse to give concentrations twice the cutoff value for positive test results: 11-nor-9-carboxy-delta-9-tetrahydrocannabinol (9-carboxy-THC), oxazepam, secobarbital, morphine, benzoylecgonine, amphetamine, or phencyclidine (PCP). Visine was then added. Although measured concentrations of several drugs were decreased in the presence of Visine, false-negative results were obtained only for 9-carboxy-THC for the EMIT-d.a.u. and TDx urine cannabinoid assays. Visine also decreased 9-carboxy-THC as measured by the Abuscreen assay. At low concentrations of Visine, false-negative cannabinoid results were attributable to the benzalkonium chloride ingredient of Visine. The added Visine was not detectable by routine urine analysis and had no effect on the activity of the glucose-6-phosphate dehydrogenase-drug conjugate used in the EMIT-d.a.u. assays. Moreover, analysis by gas chromatography/mass spectrometry showed no chemical modification or loss of 9-carboxy-THC in the Visine-adulterated urine specimens. However, Visine did increase the adhesion of 9-carboxy-THC to the borosilicate glass specimen containers. Results of ultrafiltration studies with Visine suggest that 9-carboxy-THC partitions between the aqueous solvent and the hydrophobic interior of benzalkonium chloride micelles, thereby reducing the availability of 9-carboxy-THC in antibody-based assays.
对于不含药物的尿液标本，我们添加了以下滥用药物，使其浓度达到阳性检测结果临界值的两倍：11-去甲-9-羧基-Δ⁹-四氢大麻酚（9-羧基-THC）、奥沙西泮、司可巴比妥、吗啡、苯甲酰爱康宁、苯丙胺或苯环己哌啶（PCP）。然后添加了Visine眼药水。尽管在存在Visine的情况下几种药物的测量浓度有所降低，但仅在EMIT-d.a.u.和TDx尿液大麻素检测中，9-羧基-THC出现了假阴性结果。Visine也降低了Abuscreen检测所测得的9-羧基-THC浓度。在低浓度的Visine情况下，大麻素假阴性结果归因于Visine中的苯扎氯铵成分。添加的Visine通过常规尿液分析无法检测到，并且对EMIT-d.a.u.检测中使用的葡萄糖-6-磷酸脱氢酶-药物缀合物的活性没有影响。此外，气相色谱/质谱分析表明，在掺有Visine的尿液标本中，9-羧基-THC没有化学修饰或损失。然而，Visine确实增加了9-羧基-THC与硼硅酸盐玻璃标本容器的粘附性。用Visine进行的超滤研究结果表明，9-羧基-THC在水溶剂和苯扎氯铵胶束的疏水内部之间分配，从而降低了基于抗体的检测中9-羧基-THC的可用性。
