Absorption of intra-bronchial diprophylline-methodology and preliminary results

With the objective of measuring alveolo-capillary permeability, a diprophylline solution (molecular weight 254 D) was instilled as a bolus. Instillation was performed through distallized impacted fiber bronchoscope and 3 normal volunteers and 3 patients with pulmonary fibrosis were evaluated. Blood samples were collected at regular intervals with subsequent pharmacokinetic study, mainly aimed at determining absorption kinetics. This technique enabled us to distinguish the two groups of individuals which had different absorption rates. In controls, kinetics apparently followed a simple, one compartment model for absorption, which was slower and occurred to a lesser extent. Patients with a pulmonary fibrosis had a faster and higher degree of absorption, with a larger plasma Cmax. In the latter group two-compartment kinetics for absorption was found. We conclude that absorption kinetic parameters can disclose data on structural integrity of epithelia and possible lesions of the lung interstitium.