[Synthesis and physico-chemical properties of lonazolac-Ca, a new antiphlogistic/antirheumatic agent].

Calcium-[3-(p-chlorophenyl)-1-phenylpyrazole-4]-acetate (Lonazolac-Ca, active principle of Irritren) is a new antiinflammatory/antirheumatic agent whose synthesis and physico-chemical properties are described. The physical parameters measured (pKa, partition coefficient P, saturation concentration Cs, surface activity, protein binding) are held against the corresponding values of indomethacin, diclofenac, and phenylbutazone. The size of the permeability coefficient PM of the passive transport through artificial phospholipid collodion membranes as well as the invasion curves calculated from PM indicate a good absorption of lonazolac in man.