Oxycodone-6-carboxymethyloxime hapten (Oxy4) (Oxy4)

Oxy4 is a synthetic hapten derived from oxycodone, specifically the 6-carboxymethyloxime derivative, designed for use in the development of active vaccines against opioid use disorder (OUD) (Pravetoni et al., 2012). Because oxycodone is a small molecule and not naturally immunogenic, it is chemically modified into the Oxy4 hapten and conjugated to a large immunogenic carrier protein, such as Keyhole Limpet Hemocyanin (KLH) or Cross-Reacting Material 197 (CRM197), to elicit a robust immune response (Pravetoni et al., 2014). Upon administration, the Oxy4-conjugate vaccine stimulates the production of high-affinity polyclonal antibodies that specifically recognize and bind to oxycodone and its active metabolite, oxymorphone, in the systemic circulation. This binding creates a large drug-antibody complex that is unable to cross the blood-brain barrier, effectively sequestering the opioid in the periphery and preventing it from reaching its targets in the central nervous system (Raleigh et al., 2017). This mechanism, known as immunological sequestration, aims to reduce the reinforcing effects of the drug, decrease the risk of relapse, and provide protection against lethal respiratory depression in the event of an overdose.

Other names

Oxy4Oxycodone-6-carboxymethyloximeOxycodone hapten 4Oxy4-KLHOxy4-CRM197

Active immunization leading to the production of drug-specific antibodies that sequester the drug in the systemic circulation, preventing its entry into the central nervous system.