Zur Bedeutung von Arzneistofftransportern für die Therapie pulmonaler Infektionen mit Makrolidantibiotika und Rifampicin bei Fohlen Rifampicin Makrolidantibiotikum Clarithromycin Rhodococcus equi Tuberkelbakterium Pharmakokinetik Genexpression Induktion Inhibition intrazellulär Alveolarmakrophage bronchoalveoläre Lavage The clinical outcome of o drug therapy is mainly influenced by the pharmacokinetic characteristics of the drug. Besides absorption metabolism and elimination transport processes are of major interest as well. While the impact of intestinal efflux transporters has already been investigated only little knowledge exists concerning intestinal uptake carriers or carriers responsible for the distribution of the drug into target compartments. One example are pulmonary infections. There is some evidence that drug transporters might play a role for the accumulation of drugs such as macrolides within the lung. Therefore the aim of this thesis was to investigate the expression profile of pulmonary drug transporters in the lung and in addition to that to elaborate their impact on the distribution of drugs within the different compartments of the lung namely the epithelial lining fluid and broncho alveolar lavage cells . Clinically used combination therapy of Rhodococcus equi in foals resembles a useful tool for these questions. Firstly we describe the development and validation of a LC MS MS method for the simultaneous determination of clarithromycin rifampicin and their main metabolites in horse plasma ...