PharmChem Laboratories has developed a sweat patch for detecting of cocaine and its metabolites. The FDA approved the PharmChek/TM patch for commercial sales in July 1995. All Phase I objectives were met and surpassed. During Phase I, 27 subjects were studied over a 16 day period in East Harlem, New York. Each subject provided 10 urine specimens and 24 patches worn for varied periods and provided self-reports of cocaine use to NDRI (the subcontractor). Specimens were analyzed by EMIT (urines), ELISA (patches), and by GC/MS. ELISA of patch eluate show concordance equivalent to EMIT and had appropriate specificity and sensitivity with GC/MS. The FDA-approved cutoff level (10ng/mL) was the most appropriate. The Phase II research will: 1) document major parameters about patches, 2) conduct patches studies with 125 subjects for detecting cocaine in criminal justice, drug treatment, workplace, and epidemiological markets, and 3) analyze the appropriate degree of precision for interpreting results. Each subject will be interviewed on 7 different days over a 15 day period. Specimens will be analyzed by EMIT (urines), ELISA (patches), and GC/MS (of patch eluate and positive EMIT). Two major data bases will be constructed. Staff will analyze several parameters of patch use and publish several journal articles.
As a commercial product, sweat patches may offer several advantages to urine testing: 1. noninvasive sampling technique, 2. longer periods of detection for monitoring drug use, 3. difficult to adulterate or beat, 4. ease of sample transport, and 5. deterrent effect of continuous monitoring. Patches may eventually replace urine as specimen of choice in the drug treatment, criminal justice, military, and workplace markets.
