A compound of formula: wherein: R 1 represents an immobility promoting unit selected from an organic moiety with a molecular weight lower than 1000 g/mol comprising one or more nitrogen containing moieties each with a pK a of between 4 and 7.6 at 37 °C; and R 1 is substituted or unubstituted phenylamino, imidazolyl, isoquinolinyl, quinolinyl, benzimidazolyl, acridinyl according to the following structures: wherein R 3 is straight or branched C 1-8 alkyl, or alkoxyalkyl, R 4 and R 5 are each and independent of each other hydrogen, straight or branched C 1-8 alkyl, alkoxyalkyl, or phenyl; and R 3, which is situated between the IPU: core and the NSAID, may be attached at any point on the IPU core, either on a ring carbonor nitrogen atom; -O-(C=O)- R 2 represents a acyloxy residue of a carboxylic acid group contained within a non-steroidal anti-inflammatory agent (NSAID) selected from the list consisting of: ketorolac, ketoprofen, fenoprofen, oxaprofen, diclofenac, tolmetin, tolfenamic acid, mefenamic acid, sulindac, indomethacin, acetylsalicylic acid, deflunisal, loxoprofen, indoprofen, priprofen, clidanac, fenclorac, meclofenamate, benoxaprofen, carprofen, isofezolac, aceclofenac, fenbufen, etodolic acid, fleclozic acid, amfenac, mefenamic adic, bromfenac, flenclofenac, alcofenac, orpanoxin, zomopirac, flufenamic acid, niflumic acid, pranoprofen, zaltoprofen, and suprofen, x is an integer selected from 1, 2, 3 or 4; wherein R 1 contains a group R 3 -OH, which together with the carboxylic function of the NSAID forms the ester bond, and wherein R 3 is different from -CH 2 -OH when R 3 is linked to the nitrogen of R 1; and salts, solvates and hydrates thereof. R 1 represents an immobility promoting unit selected from an organic moiety with a molecular weight lower than 1000 g/mol comprising one or more nitrogen containing moieties each with a pK a of between 4 and 7.6 at 37 °C; and R 1 is substituted or unubstituted phenylamino, imidazolyl, isoquinolinyl, quinolinyl, benzimidazolyl, acridinyl according to the following structures: wherein R 3 is straight or branched C 1-8 alkyl, or alkoxyalkyl, R 4 and R 5 are each and independent of each other hydrogen, straight or branched C 1-8 alkyl, alkoxyalkyl, or phenyl; and R 3, which is situated between the IPU: core and the NSAID, may be attached at any point on the IPU core, either on a ring carbonor nitrogen atom; -O-(C=O)- R 2 represents a acyloxy residue of a carboxylic acid group contained within a non-steroidal anti-inflammatory agent (NSAID) selected from the list consisting of: ketorolac, ketoprofen, fenoprofen, oxaprofen, diclofenac, tolmetin, tolfenamic acid, mefenamic acid, sulindac, indomethacin, acetylsalicylic acid, deflunisal, loxoprofen, indoprofen, priprofen, clidanac, fenclorac, meclofenamate, benoxaprofen, carprofen, isofezolac, aceclofenac, fenbufen, etodolic acid, fleclozic acid, amfenac, mefenamic adic, bromfenac, flenclofenac, alcofenac, orpanoxin, zomopirac, flufenamic acid, niflumic acid, pranoprofen, zaltoprofen, and suprofen, wherein R 3 is straight or branched C 1-8 alkyl, or alkoxyalkyl, R 4 and R 5 are each and independent of each other hydrogen, straight or branched C 1-8 alkyl, alkoxyalkyl, or phenyl; and R 3, which is situated between the IPU: core and the NSAID, may be attached at any point on the IPU core, either on a ring carbonor nitrogen atom; -O-(C=O)- R 2 represents a acyloxy residue of a carboxylic acid group contained within a non-steroidal anti-inflammatory agent (NSAID) selected from the list consisting of: ketorolac, ketoprofen, fenoprofen, oxaprofen, diclofenac, tolmetin, tolfenamic acid, mefenamic acid, sulindac, indomethacin, acetylsalicylic acid, deflunisal, loxoprofen, indoprofen, priprofen, clidanac, fenclorac, meclofenamate, benoxaprofen, carprofen, isofezolac, aceclofenac, fenbufen, etodolic acid, fleclozic acid, amfenac, mefenamic adic, bromfenac, flenclofenac, alcofenac, orpanoxin, zomopirac, flufenamic acid, niflumic acid, pranoprofen, zaltoprofen, and suprofen, x is an integer selected from 1, 2, 3 or 4; wherein R 1 contains a group R 3 -OH, which together with the carboxylic function of the NSAID forms the ester bond, and wherein R 3 is different from -CH 2 -OH when R 3 is linked to the nitrogen of R 1; and salts, solvates and hydrates thereof.