LPK-26 is an analog of ICI-199441 and (-)U50,488H (classic kappa agonists). It has extremely high kappa affinity (0.64 nM) and low mu and delta receptor affnities (1170 and 10,000nM). LPK-26 produces an antinocicpetive effect with much higher potency in vivo than morphine or U50488. LPK-26 does not produce physical dependence in mice, but it does suppress naloxone-induced behavioral effects in mice treated with morphine.
