Determination of apomorphine in human plasma by alumina extraction and high-performance liquid chromatography with electrochemical detection

Andrea Bolner, Luca Barbato, Franco Tagliaro, Alessandra Monge, Fabrizio Stocchi, Giampietro Nordera

Research output: Contribution to journalArticlepeer-review


Apomorphine is a powerful agonist of dopaminergic receptors which several years ago was introduced into the therapy of Parkinson's Disease. The pharmacological activity of apomorphine already appears significant at low doses. Unfortunately, the difficulty in determining the drug in plasma at low concentrations hampers the completion of accurate pharmacokinetic studies in humans. Considering the analogy of apomorphine with the molecular structure of catecholamines, the extraction of the drug from plasma was optimized by using adsorption on alumina, a technique widely used for noradrenaline and adrenaline analysis in clinical chemistry laboratories. This method proved particularly efficient and selective in apomorphine extraction from plasma prior to high-performance liquid chromatographic analysis. After pretreatment of 200 μl of plasma sample with 40 mg of alumina and 10 μl of tris buffer (pH 8.6), the drug was eluted with 200 μl of an acidic-organic solution. One volume of the supernatant was mixed with two volumes of phosphate buffer (pH 3.6), and 100 μl of the obtained mixture were injected into the HPLC system. The chromatograph was equipped with a C18 reversed-phase column and with an electrochemical coulometric detector fitted with a high-sensitivity cell (first electrode 0.00 volts, second electrode +0.35 volts). Sensitivity (20 pg of injected drug), precision (CV within assay and between assays of 3.7% and 5.6%, respectively) and accuracy were comparable to more complex analytical procedures. The miniaturisation of the entire sample pretreatment proved very advantageous for pharmacokinetics studies and, in principle, for therapeutic drug monitoring and toxicological investigations.

Original languageEnglish
Pages (from-to)81-91
Number of pages11
JournalForensic Science International
Issue number1-2
Publication statusPublished - Sep 19 1997


  • Alumina
  • Apomorphine
  • Dopamine agonises
  • Parkinson's disease

ASJC Scopus subject areas

  • Genetics
  • Analytical Chemistry
  • Pathology and Forensic Medicine
  • Psychiatry and Mental health


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