摘要:
Macromolecular prodrugs of three non-steroidal anti-inflammatory drugs (NSAIDs), ibuprofen, ketoprofen, and naproxen, were prepared by the covalent attachment of the drugs onto chondroitin sulfate (ChS) using PEG 1000 as a spacer. Drug-PEG adducts were synthesized using 1,1'-carbonyl diimidazole as a coupling agent in dimethyl sulfoxide, followed by the reaction with ChS in highly dilute aqueous solution at pH 6.8 via N-(3-dimethylaminopropyl)N'-ethylcarbodiimide hydrochloride (EDAC) as a conjugation agent. The drug-ChS con confirmed by FTIR, H-1 NMR and C-13 NMR and the molar percent of drug substitution onto ChS was characterized by H-1 NMR using the peak areas of the three protons of -phi CHCH3 on the drugs to those of -NHCOCH3 on ChS. All drug-ChS conjugates are water-soluble. The release amounts of the free drugs from their corresponding drug-ChS conjugates were evaluated in the presence or absence of either esterase or chondroitinase, and the both enzymes in pH 7.4 Tris-buffer solutions at 37 degrees C by high performance liquid chromatography (HPLC). Keto-ChS conjugates. released similar to 100% ketoprofen within 12h in the presence of esterase, but the combination with chondroitinase did not accelerate the release rate. The degradation of Keto-ChS conjugates by chondroitinase was confirmed by gel permeation chromatography (GPC). The Keto-ChS conjugates still retained the enzymatic recognition even at the substitution of ketoprofen as high as 56 mol%. The inhibition percent of carrageenan-induced edema of Keto-ChS-56 was comparable to that of a simple blend of ChS and ketoprofen, suggesting that biologically active ChS and ketoprofen could be liberated from the conjugate. (c) 2006 Elsevier B.V.All rights reserved.