Abstract: The invention provides novel compounds that are derivatives of Azithromycin and that have been found by the current inventors to have low antimicrobial activity but significant epithelial barrier enhancement properties. The invention further provides use of the compounds as a medicament, in particular in the treatment or prophylaxis of a disease or condition that is caused by a defect in epithelial cells or tissue, or a disease or condition that benefits from enhancement or restoration of epithelial barrier function, for example diseases of the respiratory tract.