Heroin and oxycodone abuse occurs over a wide range of drug doses and by various routes of administration characterized by differing rates of drug absorption. The current study addressed the efficacy of a heroin vaccine [morphine hapten conjugated to keyhole limpet hemocyanin (M-KLH)] or oxycodone vaccine [oxycodone hapten conjugated to keyhole limpet hemocyanin (OXY-KLH)] for reducing drug distribution to brain after intravenous heroin or oxycodone, or subcutaneous oxycodone. Rats immunized with M-KLH or keyhole limpet hemocyanin (KLH) control received an intravenous bolus dose of 0.26 or 2.6 mg/kg heroin. Vaccination with M-KLH increased retention of heroin and its active metabolites 6-Acetylmorphine (6-AM) and morphine in plasma compared with KLH controls, and reduced total opioid (heroin 1 6-AM 1 morphine) distribution to brain but only at the lower heroin dose. Immunization also protected against respiratory depression at the lower heroin dose. Rats immunized with OXYKLH or KLH control received 0.22 or 2.2 mg/kg oxycodone intravenously, the molar equivalent of the heroin doses. Immunization with OXY-KLH significantly reduced oxycodone distribution to brain after either oxycodone dose, although the magnitude of effect of immunization at the higher oxycodone dose was small (12%). By contrast, vaccination with OXY-KLH was more effective when oxycodone was administered subcutaneously rather than intravenously, reducing oxycodone distribution to brain by 44% after an oxycodone dose of 2.3 mg/kg. Vaccination also reduced oxycodone-induced antinociception. These data suggest that the efficacy of OXY-KLH and M-KLH opioid vaccines is highly dependent upon opioid dose and route of administration.
|Original language||English (US)|
|Number of pages||8|
|Journal||Journal of Pharmacology and Experimental Therapeutics|
|State||Published - May 2018|
Bibliographical noteFunding Information:
This work was supported by the National Institutes of Health National Institute on Drug Abuse [Grant U01DA038876] (to M.P. and P.R.P.). https://doi.org/10.1124/jpet.117.247049. s This article has supplemental material available at jpet.aspetjournals.org.
© 2018 by The American Society for Pharmacology and Experimental Therapeutics.