To provide derivatives of N-methyl-N-[(1S)-1-phenyl-2-((3S)-3-hydroxypyrrolidin-1-yl)ethyl]-2,2-diphenylacetamide having a covalently bonded acid.

There are provided the derivatives and salts, solvates, and prodrugs thereof, the use of these derivatives in the production of pharmaceuticals, the use of these derivatives in the production of pharmaceutical compositions, methods for the production of the pharmaceutical compositions, pharmaceutical composition obtained by the methods, and methods for treating diseases comprising administering the pharmaceutical compositions to patients.