tailieunhanh - Drugs and Poisons in Humans - A Handbook of Practical Analysis (Part 22)

Introduction: Cocaine is an alkaloid being contained in the leaves of Erythroxylon coca Lam. or Erythroxylon novogranatense (Morris) Hieronymus of Erythroxylaceae plants. The compound is being used as a local anaesthetic. It also shows stimulating action on the central nervous system; when it is used continuously, psychic dependence on its use appears, resulting in its chronic toxicosis [1]. Cocaine is being abused worldwide; its abuse is most serious in the north and south American continents. Fortunately, in Japan, its abuse is not so many; but it cannot be overlooked. In this chapter, the methods of extractiona and GC/MS analysis for. | 2. Cocaine and its metabolites by Kenichi Takekawa Introduction Cocaine is an alkaloid being contained in the leaves of Erythroxylon coca Lam. or Erythroxylon novogranatense Morris Hieronymus of Erythroxylaceae plants. The compound is being used as a local anaesthetic. It also shows stimulating action on the central nervous system when it is used continuously psychic dependence on its use appears resulting in its chronic toxicosis 1 . Cocaine is being abused worldwide its abuse is most serious in the north and south American continents. Fortunately in Japan its abuse is not so many but it cannot be overlooked. In this chapter the methods of extraction and GC MS analysis for cocaine and its main metabolites such as ecgonine methyl ester EME and benzoylecgonine BE in urine and blood are presented a fatal cocaine poisoning case which the author experienced is also demonstrated. Chemical synthesis of the metabolite standards 2 Cocaine hydrochloride Shionogi Co. Ltd. Osaka Japan Takeda Chem. Ind. Ltd. Osaka Japan or Sigma St. Louis MO USA is dissolved in M hydrochloric acid aqueous solution and heated at 90 C with refluxing gentle mixing for 24 h to produce ecgonine. The solution is extracted with ethyl ether to remove benzoic acid. The dried residue of ecgonine hydrochloride is dissolved in 10 hydrochloric acid methanolic solution for its methylation to synthesize EME 2 . Aqueous solution of cocaine hydrochloride is carefully adjusted to pH 7 by repeated addition of M NaOH solution with refluxing for 3 days precipitated BE can be obtained. For more details of procedure see reference 2 . Reagents and their preparation Bond Elut Certify LRC b Varian Harbor City CA USA Extrelut c Merck Darmstadt Germany M Phosphate buffer solution pH 6 g of potassium dihydrogenphosphate is dissolved in 900 mL distilled water and its pH is adjusted to by adding M potassium hydroxide solution the final volume is brought to 1 000 mL by adding distilled .