The present invention relates to novel morphine-6-glucuronide derivatives, topharmaceutical compositions containing them and to uses thereof. Said derivatives havethe following structures, where the group Pcntite (A), except substituents X,is called M6G-NR1 R2-S-, R1 = saturated or unsaturated, straight- orbranched-chain C-Calkyl, the alkyl chain being optionally interruptedby one or more heteroatoms selected from O, S and N, R2 = H, saturated or unsaturated,straight- or branched-chain C-Calkyl, or an aryl, heteroarylor (C-C) alkylaryl group, R3 = Y(C=Z)R or YR, Y and Z independently= O or S, R = saturated or unsaturated, straight- or branched-chain C-Calkyl with the proviso that R3 is not -O-CHX = H, an -S-R4-W group,or a MR,6G-NR I R2-S- group, with R4 = saturated or unsaturated, straight- or branched-chainC -Calkyl which can include amide, ester or ether bondsand W is either a δ-receptor antagonist, or a K-receptor antagonist anda pharmaceutically acceptable salt thereof.
