title: Stability of morphine, codeine, and 6-acetylmorphine in blood at different sampling and storage conditions.
abstract: The stability of drugs in biological specimens is a major concern during the evaluation of the toxicological results. The stability of morphine, codeine, and 6-acetyl-morphine in blood was studied after different sampling conditions: (i) in glass, polypropylene or polystyrene tubes, (ii) with addition of dipotassium ethylene diamine tetraacetic acid (K2EDTA) or sodium oxalate (Na2C2O4), and (iii) with or without the addition of sodium fluoride (NaF). Spiked blood samples were stored at two different temperatures (4 and -20°C), analyzed after different storage times and after three freeze–thaw cycles. Opiate concentrations were decreased in all conditions, but the most unstable was 6-acetyl-morphine. The addition of NaF as preservative improved the stability of opiates at all conditions studied, whereas the type of anticoagulant did not affect the stability of opiates. It was concluded that blood samples should be stored at -20°C in glass tubes containing oxalate and NaF for maximum stability.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Papoutsis
authors.forename: Panagiota
authors.initials: P
authors.lastname: Nikolaou
authors.forename: Constantinos
authors.initials: C
authors.lastname: Pistos
authors.forename: Artemisia
authors.initials: A
authors.lastname: Dona
authors.forename: Maria
authors.initials: M
authors.lastname: Stefanidou
authors.forename: Chara
authors.initials: C
authors.lastname: Spiliopoulou
authors.forename: Sotirios
authors.initials: S
authors.lastname: Athanaselis
mesh_terms: D000925:Anticoagulants / Q000737:chemistry; D003061:Codeine / Q000097:blood*; D003080:Cold Temperature; D004355:Drug Stability; D004492:Edetic Acid / Q000737:chemistry; D053593:Forensic Toxicology; D008401:Gas Chromatography-Mass Spectrometry; D005898:Glass; D006801:Humans; D009020:Morphine / Q000097:blood*; D009022:Morphine Derivatives / Q000097:blood*; D009294:Narcotics / Q000097:blood*; D019815:Oxalic Acid / Q000737:chemistry; D011126:Polypropylenes; D011137:Polystyrenes; D011310:Preservatives, Pharmaceutical / Q000737:chemistry; D012969:Sodium Fluoride / Q000737:chemistry; D013048:Specimen Handling / Q000295:instrumentation / Q000379:methods*; D013997:Time Factors
chemical_list: D000925:Anticoagulants; D009022:Morphine Derivatives; D009294:Narcotics; D011126:Polypropylenes; D011137:Polystyrenes; D011310:Preservatives, Pharmaceutical; D009020:Morphine; D012969:Sodium Fluoride; D019815:Oxalic Acid; D004492:Edetic Acid; C026979:6-O-monoacetylmorphine; D003061:Codeine