Using amphetamine isomer ratios to determine the compliance of amphetamine abusers prescribed dexedrine

The amphetamine isomer ratios (l-amphetamine/d-amphetamine) in 373 urine specimens submitted for analysis over a two-year period have been determined using a chiral derivatizing agent in conjunction with a gas chromatograph fitted with a nitrogen-specific detector. All of the specimens were collected from known or suspected amphetamine abusers, some of which were prescribed dexedrine for maintenance and detoxification. The mean (+/- 1 standard deviation [SD]) l/d-amphetamine isomer ratio for 147 specimens from compliant subjects prescribed dexedrine was 15.0% (+/- 4.9%). The mean (+/- 1 SD) l/d-amphetamine isomer ratio from 165 subjects abusing illicit amphetamine was 98.5 (+/- 27.5%). The calculation of l/d-amphetamine isomer ratios in urine has been found to be a rapid method for determining the compliance of subjects prescribed dexedrine and is therefore a useful technique for the continued management of amphetamine abusers. In addition, 17 specimens of illicit amphetamine powder (assumed to be a racemic mixture) were submitted to the laboratory for analysis. Using a combination of gas chromatography with and without chiral derivatization, the powders were found to have a mean l/d-amphetamine isomer ratio of 89.2% (range 72.2% to 98.3%) and mean purity (w/w) of 21.5% (range 3.4% to 71.0%) relative to pure dl-amphetamine substance.