KA-104, a new multitargeted anticonvulsant with potent antinociceptive activity in preclinical models.

OBJECTIVE: The main objective of the present work was to assess the utility of KA-104 as potential therapy for drug-resistant seizures and neuropathic pain, and to characterize its druglike properties in a series of absorption, distribution, metabolism, excretion and toxicity (ADME-Tox) studies. We also aimed to establish its mechanism of action in electrophysiological studies. METHODS: The activity of KA-104 against drug-resistant seizures was tested in the mouse 6-Hz (44-mA) model, whereas the antinociceptive activity was assessed with the capsaicin- and oxaliplatin-induced pain models in mice. The patch-clamp technique was used to study the influence of KA-104 on fast voltage-gated sodium currents in rat prefrontal cortex pyramidal neurons. The pharmacokinetic profile was determined after intraperitoneal (ip) injection in mice. The in vitro ADME-Tox properties were studied by applying routine testing procedures. RESULTS: KA-104 was effective in the 6-Hz (44-mA) model (median effective dose [ED50 ] = 73.2 mg/kg) and revealed high efficacy in capsaicin-induced neurogenic pain as well as in oxaliplatin-induced neuropathic pain in mice. Patch-clamp technique showed that KA-104 reversibly inhibits voltage-gated sodium currents. KA-104 was rapidly absorbed after the ip injection and showed relatively good penetration through the blood-brain barrier. This molecule was also characterized by high passive permeability, moderate influence on CYP2C9, and negligible hepatotoxicity on HepG2 cells. SIGNIFICANCE: The results reported herein indicate that KA-104 is a new wide-spectrum multitargeted anticonvulsant with favorable in vitro ADME-Tox properties. Importantly, this compound may also prove to become an interesting and hopefully more effective therapeutic option for treatment of neuropathic pain.