Figure 3.

Serum sequestration of drugs in vitro. Pooled serum samples from indicated weeks were diluted with a buffer that contained 5 nM of indicated drugs and dialyzed against buffer in an equilibrium dialysis plate. Sodium fluoride (3–4 mg/mL) was added to the buffer to impede heroin degradation. Drug concentrations in the sample and buffer chambers were determined after 24 h, and fraction bound was calculated. Serum binding from monovalent immunization: (a) Fentanyl from TT-para-AmFenHap group and (b) 6-AM from TT-6-AmHap group. Serum binding from bivalent immunization: (c) fentanyl, (d) 6-AM, (e) heroin, and (f) morphine. Data shown are mean ± SEM of triplicate determinations.