In 1949, after the Second World War, Erhardt succeeded Bockmühl as the head of the entire pharmaceutical research division of Hoechst AG.
[3] Ehrhart was awarded honorary doctorate degrees by the universities of Graz, Mainz, Frankfurt, Stuttgart, and Gießen.
In the first animal experiments, Ehrhart and Bockmühl found that VA 10820 had a five- to ten-fold stronger analgesic effect than pethidine.
Due to the expropriation of IG Farben's patents and recipes, VA 10820 came to the United States, where it was given the international nonproprietary name methadone in 1949.
In January 1949 Hoechst AG, which had re-formed after the dissolution of IG Farben with Ehrhart as its research director, marketed methadone as a strong painkiller under the brand name Polamidone.