In vitro Binding of Tetracyclines to Calcium

Abstract

SINCE antibiotics of the tetracycline series were first demonstrated to localize and persist in vivo specifically in newly proliferated bone and in certain areas of calcified cartilage¹, it appears to have been generally accepted that these antibiotics do in fact bind to calcium ions in at least crystal-seeded nucleation sites on collagen fibrils and in other physiologically ‘available’ calcium-impregnated protein matrices. Nevertheless, some little controversy seems to have arisen recently owing both to the presence of diffuse though minimal localization of tetracycline fluorescence in non-growing skeletal areas² and, as cited in the original communications, the apparent, often transient, localization of these drugs in certain grossly non-calcified soft tissues.