The enhancement of anti-inflammatory activity of NSAID agents by co-treatment with zinc salts was demonstrated previously [8,14]. Chronic treatment with ZHA induces a more robust enhancement of the anti-inflammatory activity of ketoprofen than single or subchronic ZHA administration [8].
In the present study chronic administration of ZHA, similarly to single or sub-chronic ZHA administration [8] did not exhibit analgesic properties in the applied paradigm. Moreover, the effectcombined ZHA treatment with different doses of ketoprofen is not quite clear. ZHA administration enhances only a higher dose (20 mg/kg) of ketoprofen. The mechanism of such interaction should be examined in future studies.