The effects of a sulfonic acid dye and a surfactant on the pulmonary absorption of fluorescein isothiocyanate-labelled dextran (FITC-dextran), a model macromolecular compound (MW=150000) which is not absorbed after pulmonary administration, were studied. Bromphenol blue, a sulfonic acid dye, did not show an enhancing effect. However, sodium glycocholate (SGC) considerably enhanced the pulmonary absorption of FITC-dextran. Therefore, SGC may be a useful additive to increase the systemic availability of macromolecular compounds administered as aerosol dosage forms.
