Microemulsions and its use for preventing airway diseases

A microemulsion not containing any active pharmaceutical agent, said microemulsion 5 comprising 35% by weight of a nonpolar animal or vegetable oil, 10 to 55% by weight of at least one polar solvent selected from the group of water, a buffer , an alcohol and mixtures thereof and at least one surfactant selected from a polysorbate, a poloxamer and a fatty acid polyoxyethylene, characterized in that further comprises 20-50% by weight of a monoacylglyceride.