Approaches to Drug Sample Differentiation. I: A Conceptual Review

Abstract

Differentiation of drug samples can be based on at least three different approaches. Conventional methods use qualitative and quantitative determinations of impurities or minor components. Samples may also be differentiated by variations in a naturally occurring isotope such as carbon-13, whose content varies because of differences of carbon fixation conditions for cultivated plant drugs or from differences in reaction conditions for synthesized drugs. A third approach involves the determination of various diastereoisomeric or enantiomeric compositions or both. This last approach also serves an essential purpose in cases where one isomer is under regulation while other(s) may not be. Representative works are reviewed.

Synthesis and liquid chromatographic evaluation of some chiral derivatizing agents for resolution of amine enantiomers

“…This importance is illustrated in cases where one enantiomer is under regulatory control while the other is not. In addition, the enantiomeric makeup of a sample may give an indication as to its origin (14). Hufsey and Cooper (15) report that certain drugs derived from a natural source usually exist in one enantiomeric form while the synthesized counterpart is usually a mixture of enantiomers.…”

Gas chromatographic/mass spectrometric determination of carbon isotope composition in unpurified samples: Methamphetamine example

“…It is interesting to note that the deviation is of a systematic nature, which will not diminish the accuracy attainable in comparing the levels of enrichment among samples. 13 …”