N. Uemura

Delayed disposition of cocaine in sweat patches and in skin blister: cocaine may migrate from plasma to sweat patches via interstitial fluid

Sweat patch analysis is extensively used for drug abuse monitoring. The present study investigates how cocaine migrates to sweat patches. In the cumulative collection model, the drug absorption rate in patches should be proportional to the drug concentration in the preceding disposition compartment if drug back‐transfer is negligible. Therefore, we measured the slopes of cocaine concentration curves in patches as a marker for absorption rate (into patches) after a single dose of cocaine‐d5 (1mg/kg over 60 min) in healthy cocaine users (n=5). Patches were placed on the back of subjects prior to drug administration and removed at 0–72 hr postdose. Blood and interstitial fluid (skin blister fluid) were collected up to 72 hr. Patch cocaine levels showed semi‐cumulative collection with peaks between 8 and 48 hr. Cocaine levels in plasma and interstitial fluid peaked at 1.0±0 and 5.3±0.6 hours postdose, respectively, suggesting a delayed cocaine disposition in the interstitial fluid. Similarly, patch cocaine absorption was delayed with rate peaks at 4.3±2.9 hr postdose. Tmax for plasma benzoylecgonine (BE) was 5.0±2.4 hr. BE also showed a delayed peak in the interstitial fluid at 11.3±11.0 hr post, and the highest BE absorption in patches was observed in a similar time range of 12.4±4.9 hr. Cocaine and its metabolite migrate into patches in a time period that coincides with Tmax in interstitial fluid. Cocaine seems to travel from plasma to sweat patches via interstitial fluid.

Pharmacokinetics of intravenous d- and l-methamphetamine in healthy volunteers

Methamphetamine has a chiral structure. The aim of the present study was to assess the pharmacokinetics of methamphetamine enantiomers in humans.

Three Day 12-Hour Cocaine Infusion Produces Tolerance in Cardiovascular and Subjective Effects, But Does Not Alter Cocaine Self-Administration Behavior in Humans

Clinical Pharmacology & Therapeutics (2003) 73, P91–P91; doi:

The Cardiovascular Effects of D- and L-Methamphetamine

Clinical Pharmacology & Therapeutics (2003) 73, P36–P36; doi:

Sustained 3-Day Intravenous Cocaine Exposure Decreases Appetite and Hunger But Does Not Alter Food Intake Patterns in Cocaine-Dependent Volunteers

Clinical Pharmacology & Therapeutics (2003) 73, P35–P35; doi: