In Vitro Evaluation of the Mucolytic Action of Urea

Urea has a mucolytic action on purulent or mucoid sputum when added in extremely large amounts (more than 0.2 gm urea per milliliter of sputum). No practical means for utilizing this action for aerosol therapy in lung disorders is foreseen since effective amounts of urea cannot be delivered into the lungs by any currently available method. The action of urea was shown to be irreversible and to be accompanied by the release of acid-soluble tyrosine in the sputum. Urea crystals may be useful for liquefying pus in decubitus ulcers or other sites of infection, or for liquefying sputum in preparation for bacteriologic studies.