[Binding capacity of ibuprofen to muscle proteins]

From former studies it is well known, that ibuprofen (CAS 15687-27-1) binds to muscular tissue in a higher degree than to tendons or ligaments. It is not known, however, what constituents of muscle tissue are responsible for this binding. Therefore the binding capacity of ibuprofen to different muscular proteins was studied. Actin, actomyosin, myosin, myoglobin, tropomyosin, lecithin, and native human collagen type I were incubated with 14C-ibuprofen and the specific binding was measured in relation to the total radioactivity. It could be shown that ibuprofen binds most markedly to actin. This binding could be inhibited by pre-incubation of ibuprofen with soluble actin. In comparison to the other proteins studied the specific binding of ibuprofen to actin was 4 to 5 times higher. As actin is a constituent of the cytoskeleton which plays an important role in generating oxygen radicals, its possible inhibition by ibuprofen could additionally explain the antiphlogistic effect of this compound.