Provided is a drug-conjugate product obtained by reacting the drug with an alpha-amino acid selected from Lys, Leu, He, Gly, Asp, Glu, Met, Ala, Val, His, Nor, Arg, Phe, Trp, Hsr, Car, Ort, Cav, Asn, GIn, Can, Tau, Djk, GABA, Cys, Dcy and Sar, under conditions effective to form a compound having a covalent bond between the drug and the amino acid, wherein the drug is selected from a list of specified drugs (including ibuprofen and aspirin).
