In our times drug delivery systems becomes more and more interesting. Because of this more and more groups analyze the behavior of so called polymersomes, which are vesicles from amphiphilic block copolymers as drug delivery systems. One of the most important characteristics of these systems is the permeability of the membranes, especially for a given encapsulated compound. To analyze the exchange through such membranes we use the combination of nuclear magnetic resonance echo experiments with pulsed field gradients (PFG-NMR). We synthesize vesicles from four different amphiphilic blockcopolymers and observe their suitability as drug delivery systems. Therefore we analyzed which membrane represents the largest barrier for water. Additionally we examine the effect of the bilayer thickness on the permeability as well as the effect of the temperature and the pH-value. At last the effect of the used tracer was analyzed and the exchange behavior of three models for drugs was measured.