Prodrug derivatives of carboxylic acid drugs

Compounds of the formula I ##STR38## wherein R--COO-- represents the acyloxy residue of a carboxylic acid drug or medicament selected from:

• Indomethacin
• Naproxen
• Ibuprofen
• Flurbiprofen
• 5-Aminosalicylic Acid
• L-Dopa
• Furosemide and
• N-Acetylcysteine
• and R.sub.1 and R.sub.2 are the same or different and are selected from a group consisting of an alkyl group, an alkenyl group, an aryl group, an aralkyl group, a cycloalkyl group, in which the alkyl, alkenyl, aryl, aralkyl or cycloalkyl group is unsubstituted or substituted with one or more substituents selected from:
• a halogen atom,
• a hydroxy group,
• a straight or branched-chain alkoxy group having the formula R.sub.3 --O--, wherein R.sub.3 represents an alkyl group or an aryl group, which groups may be unsubstituted or substituted with one or more of a halogen atom or a hydroxy group,
• a carbamoyl group having the formula ##STR39## wherein R.sub.4 and R.sub.5 are the same or different and are hydrogen, an alkyl group or are selected from a group having the formula --CH.sub.2 NR.sub.7 R.sub.6, wherein R.sub.6 and R.sub.7 are the same or different and are hydrogen, or an alkyl group,
• an amino group having the formula --NR.sub.8 R.sub.9, wherein R.sub.8 and R.sub.9 are the same or different and are hydrogen, or an alkyl group
• an acyloxy group having the formula --COOR.sub.10, wherein R.sub.10 is an alkyl, aryl or aralkyl group,
• an oxyacyl group having the formula R.sub.11 COO-- wherein R.sub.11 is hydrogen, an alkyl group, an aryl group, an aralkyl group, a cycloalkyl group, in which the alkyl, aryl, aralkyl or cycloalkyl group is unsubstituted or substituted with one or more of a halogen atom, a hydroxy group, an alkoxy group of the formula R.sub.3 --O-- as defined above, a carbamoyl group of the formula --CONR.sub.4 R.sub.5 as defined above or an amino group having the formula --NR.sub.8 R.sub.9 as defined above;
• and nontoxic pharmaceutically acceptable acid addition salts thereof.