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CLINICAL TOXICOLOGY AUGUST 2012 CHIRAL SEPARATION A SUPPLEMENTARY TEST SERVICE TO IDENTIFY THE SOURCE OF METHAMPHETAMINE USE Positive test result for methamphetamine in urinary samples always raises a red flag for illicit methamphetamine use in patients. A common question ensued is, "What is the source of methamphetamine?" (e.g., from street drugs or prescription drugs), since several prescription drugs and one over-the-counter inhaler can either contain or be converted to methamphetamine. Methamphetamine is naturally chiral. Two isomers of methamphetamine, l and d-methamphetamine, exhibit similar pharmacokinetic, but totally different, pharmacological properties; with dmethamphetamine having psychoactive property and abuse liability and l-methamphetamine having minimal psychostimulatvie effect. With known information for chiral composition in different settings, a d/l isomer ratio would greatly facilitate physicians’ judgment on the source of methamphetamine. American Clinical Solutions, in collaboration with NMS Labs, is excited to present a novel methamphetamine chiral resolution service based on a GC/MS method. As a supplementary test service to UPLC/MS quantitation, chiral separation is capable of separating l-methamphetamine from its d-isomer and generating a report for the ratio of d versus l-isomer. Therefore, after UPLC/MS quantitation of methamphetamine (both l and disomers) in a sample, a positive sample can be further tested by GC/MS to determine the d/l isomer ratio. If a d/l ratio is equal to or less than 13%, it would suggest that methamphetamine is predominantly l isomer and therefore, it most likely comes from a Vicks inhaler and Selegiline. A d/l ratio greater than 13% would highly suggest the use of schedule II psychostimulants. Next, a review of the patient’s prescription history would further reveal whether dmethamphetamine is converted from legal prescription drugs or from illicit drug abuse. So far, prescription drugs having been reported as a precursor to d-methamphetamine are benzphetamine, and dimethylamphetamine, famprofazone, fencamine, and fufenorex. For a patient without prescription history for these drugs, it would highly suggest an illicit use of methamphetamine. Methamphetamine positive (≥ 100 ng/ml) Chiral separation for d/l ratio* d/l ratio 13% d/l ratio 13% Vicks inhaler, With prescription: Without prescription: Selegiline benzphetamine Highly suggest from dimethylamphetamine illicit source famprofazone fencamine fufenorex Urine and Oral Fluid Confirmatory Drug Testing Laboratory - Support pain management - Monitor compliance - Identify undisclosed medications Cheng Fang, MD., PH D., DABT | [email protected] 721 Cortaro Dr, Sun City Center, FL 33573 | T 866-762-8379 | F 813-634-4538