The mucolytic activity of amides: a new approach to mucus dispersion.

A method which will reduce significantly the viscosity of epithelial mucus is essential to the physiological mechanisms involved in the mobilization and removal of such secretions. The life expectancy of patients with chronic pulmonary conditions and cystic fibrosis has been considerably increased and consequently the problem of liquefying mucin acquires new importance. In view of these considerations, as well as to facilitate research into the structural relationship of the glycoprotein macromolecule, a systematic investigation of mucolysis was undertaken using gastric mucin. Three amides, carbamide, acetamide and formamide, were found to dissolve gastric gel mucin with minimal degradation, and rapidly disperse the viscous secretions produced in pathological conditions of the tracheobronchial tree. Their effect on secretions from patients with cystic fibrosis and bronchiectasis is dramatic, and within five minutes of adding the reagent the flow time was reduced by at least 95%. Clinical studies were carried out with carbamide (urea in anhydrous, lyophilized, sterile powder form) in 32 patients with a variety of bronchial conditions, including chronic bronchitis, cystic fibrosis, asthma, bronchiectasis and emphysema. With the concentrations used, no irritant, bronchospastic or other reactions were observed.IT IS CONCLUDED THAT AMIDES OF THIS TYPE HAVE AT LEAST TWO ACTIONS ON THE EPITHELIAL MUCOUS SECRETION: (1) breakage of the three-dimensional gel structure and (2) a slower reduction in viscosity followed by solution of the solid material.