RT Journal Article SR Electronic T1 Dynorphin A (1–8) Analog, E-2078, Is Stable in Human and Rhesus Monkey Blood JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 1147 OP 1151 VO 280 IS 3 A1 Jim Yu A1 Eduardo R. Butelman A1 James H. Woods A1 Brian T. Chait A1 Mary Jeanne Kreek YR 1997 UL http://jpet.aspetjournals.org/content/280/3/1147.abstract AB E-2078 is a dynorphin A (1–8) analog, [N-methyl-Tyr1, N-methyl-Arg7-d-Leu8] Dyn A (1–8) ethylamide. Its biochemical stability against enzymatic degradationin vitro in human and rhesus monkey blood, and in vivo in rhesus monkey blood was studied using matrix-assisted laser desorption/ionization mass spectrometry. In vitrostudies were carried out in freshly drawn human and rhesus monkey blood, incubated at 37°C for various time periods. In vivostudies were conducted by E-2078 i.v. injection to rhesus monkeys, and blood samples were collected at various time points after the injection. It was found that E-2078 was stable against enzymatic degradation in vitro in freshly drawn human and rhesus monkey blood. Minor biotransformation products from E-2078, such as E (1–4), E (1–5) and E (3–6), were detected in vitro in some human and rhesus monkey blood, but they made up less than 5% of the total starting E-2078 peptide. No biotransformation products were detected in the blood samples from in vivo studies. The apparent half-life of elimination of E-2078 in vivo from the rhesus monkey blood was determined to be 44.0 min. The American Society for Pharmacology and Experimental Therapeutics