A New Tetracycline Derivative with Elective Lung Affinity

¹ Medical Director

The results of research carried out in order to study the lung affinity of a new tetracycline derivative, guamecycline or N₁,N₁-diethyleniminobiguanidomethyl-tetracycline, are reported. First the results of the studies carried out on animals are reported, and then the data relative to the antibiotic levels present in the bronchial secretion of tracheotomized patients treated orally with guamecycline, and equivalent doses of tetracycline HCl (the guamecycline molecule has a content of 68.75 percent tetracycline HCl). Bronchial secretions were drawn off by vacuum through the tracheotomy tube at different intervals after the treatments. In a follow-up study, the antibiotic levels present in lung tissue were measured in patients who underwent lobectomy and who were treated previously with guamecycline by oral route, or with equivalent doses of tetracycline HCl. The results of the two studies, stastically analyzed, have shown that guamecycline concentrates in bronchial secretion and in lung tissue in signicantly higher quantities than tetracycline HCl.