Proof-of-Concept for the Analgesic Effect and Thermoregulatory Safety of Orally Administered Multi-Target Compound SZV 1287 in Mice: A Novel Drug Candidate for Neuropathic Pain

SZV 1287 (3-(4,5-diphenyl-1,3-oxazol-2-yl)propanal oxime) is a novel multi-target candidate under preclinical development for neuropathic pain. It inhibits amine oxidase copper containing 3, transient receptor potential ankyrin 1 and vanilloid 1 (TRPV1) receptors. Mainly under acidic conditions, it is transformed to the cyclooxygenase inhibitor oxaprozin, which is ineffective for neuropathy. Therefore, an enterosolvent capsule is suggested for oral formulation, which we investigated for nociception, basic kinetics, and thermoregulatory safety in mice. The antihyperalgesic effect of SZV 1287 (10, 20, 50, and 200 mg/kg, p.o.) was determined in partial sciatic nerve ligation-induced traumatic neuropathy by aesthesiometry, brain and plasma concentrations by HPLC, and deep body temperature by thermometry. Its effect on proton-induced TRPV1 activation involved in thermoregulation was assessed by microfluorimetry in cultured trigeminal neurons. The three higher SZV 1287 doses significantly, but not dose-dependently, reduced neuropathic hyperalgesia by 50% of its maximal effect. It was quickly absorbed; plasma concentration was stable for 2 h, and it entered into the brain. Although SZV 1287 significantly decreased the proton-induced TRPV1-mediated calcium-influx potentially leading to hyperthermia, it did not alter deep body temperature. Oral SZV 1287 inhibited neuropathic hyperalgesia and, despite TRPV1 antagonistic action and brain penetration, it did not influence thermoregulation, which makes it a promising analgesic candidate.

A review of the emerging profile of the anti-inflammatory drug oxaprozin

Oxaprozin is a nonsteroidal anti-inflammatory drug characterised by a propionic acid-based structure. It is able to diffuse easily into inflamed synovial tissues after oral administration. Although discovered > 20 years ago, it is now under intensive investigation because of its unusual pharmacodynamic properties. Other than being a nonselective cyclooxygenase inhibitor, the drug is capable of inhibiting both anandamide hydrolase in neurons (median inhibitory concentration [IC50] = 85 micromol/l), with consequent potent analgesic activity, and NF-kappaB activation in inflammatory cells (IC50 = 50 micromol/l). Moreover, oxaprozin induces apoptosis of activated monocytes in a dose-dependent manner, with the effect being detectable at a concentration of 5 micromol/l and reaching the maximum activity at 50 micromol/l. As monocyte-macrophages and NF-kappaB pathways are crucial for synthesis of proinflammatory and histotoxic mediators in inflamed joints, oxaprozin appears to be endowed with pharmacodynamic properties exceeding those presently assumed as markers of classical nonsteroidal anti-inflammatory drug.