[Preparation and antiinflammatory activity of selected aqua-(aryloxyacetate) zinc complexes]

Mononuclear aqua(aryloxyacetato)zinc(II) complexes of the composition [Zn(H2O)2(ROCH2COO)2] (R = phenyl, o-, m-, p-tolyl) were prepared as potential anti-inflammatory agents. The results of elemental analysis and parameters of IR spectra allow to classify the above-mentioned compounds to the group of carboxylatozinc(II) complexes with a distorted octahedral structure. They were assayed in rat paw carrageenan-induced edema and antiedematous effects were compared to those of free acids. Salicylic acid and its zinc(II) and copper(II) salts were used as the standards of comparison. All compounds were administered i.p. in a single dose of 50 mumol/kg body weight (calculated for the carboxylate fragment). In general, the zinc(II) complexes tested were clearly more effective (expressed as a mean edema reduction of 58-70-68-59%), including zinc(II) salicylate dihydrate (64%), than the uncomplexed acids (37-26-50-48%). Copper(II) salicylate tetrahydrate (60%) and salicylic acid (57%) exhibited comparable effects under the same conditions. The observed activities of the complexes are discussed in relation to their structures as well as to the coordination-chemical properties of the acidoligands under study.