In vivo testing of the anti-inflammatory action of topical formulations containing cobalt complexes with oxicams.

INTRODUCTION: The aim of this study was to assess the anti-inflammatory action of semisolid gel emulsions containing cobalt complexes with ligands of oxicams class, i.e. piroxicam and meloxicam, in vivo, on the inhibition of hind paw edema induced in rats, using a carrageenan solution as a positive control and a digital plethysmometer. METHODS: The two substances (salts of the oxicam, i.e. meloxicam or piroxicam, with cobalt), alone or in combination, have been embedded in a hydrophilic matrix in the form of aqueous dispersions, co-solvent system including ethanol and at least one promoter of absorption. Two reference topical products were used to establish the anti-inflammatory action. RESULTS: After 60 minutes of inducing the edema, the MxCo 0.05% (ISO) and MxCo 0.56% (ISO) formulations displayed the most pronounced anti-inflammatory effect, 88% and 84% respectively. At 120 minutes, the effect was between 68-74%, whereas for samples with PxCo 0.05% (ISO), PxCo 0.05% (IPM) and MxCo 0.1% (IPM) the effects were at the lower limits of 29.95%, 20.68% and 23.4%, respectively. After 180 minutes, the most pronounced anti-inflammatory effect was assigned to MxCo 0.56% (ISO) at 78%, followed by MxCo 0.05% (ISO) with 75%, and MxCo 0.1% (IPM) at 31.17%. At 24 hours after administration of the phlogistic agent, both samples, PxCo 0.05% and MxCo 0.1% (IPM), retained their anti-inflammatory effect, but at a lower level, while MxCo 0.05% (ISO) and 0.56% (ISO) had a greater anti-inflammatory effect (>60%). CONCLUSIONS: Several tested topical formulations showed a higher anti-inflammatory effect compared to the used reference products, as depicted by the inhibition of edema induced to the hind paw of rats with a phlogistic agent, a carrageenan solution. [ABSTRACT FROM AUTHOR]