Design, synthesis, biological evaluation, and nitric-oxide release studies of a novel series of celecoxib prodrugs possessing a nitric-oxide donor moiety

A new group of hybrid nitric oxide-releasing anti-inflammatory drugs (NONO-coxibs), in which an O 2-acetoxymethyl-1-(N-ethyl-N-methylamino)diazen-1-ium-1,2-diolate NO-donor moiety is attached directly to the carboxylic acid group of 1-(4-aminosulfonylphenyl)-5-aryl-1H-pyrazol-3-carboxylic acids (6a-c), were synthesized. A low amount of NO was released from the diazen-1-ium-1,2-diolate compounds 6a-c upon incubation with phosphate buffer saline (PBS) at pH 7.4 (range: pH 7.97-8.51), whereas, the percentage of NO released was significantly higher (84.5%-85.05% of the theoretical maximal release of two molecules of NO/molecule of the parent hybrid ester prodrug) when the diazen-1-ium-1,2-diolate ester prodrugs were incubated in the presence of rat serum. These incubation studies demonstrated that both NO and the anti-inflammatory 1-(4-aminosulfonylphenyl)-5-(4-H, 4-F or 4-Me-phenyl)-1H-pyrazol-3-carboxylic acid (4a-c) would be released from the parent NONO-coxib upon in vivo cleavage by non-specific serum esterases. The parent compounds 4a-c displayed good anti-inflammatory effects (ID50=81.4-112.4 mg/kg p.o.) between those exhibited by the reference drugs, aspirin (ID50=114.3 mg/kg p.o.) and celecoxib (ID50=12.6 mg/kg p.o.). Hybrid ester anti-inflammatory/NO-donor prodrugs (NONO-coxibs) offer a potential drug-design concept directed toward the development of anti-inflammatory drugs that are lacking adverse ulcerogenic and/or cardiovascular effects.本研究合成了一类新型杂合型一氧化氮（nitric oxide，NO）释放抗炎药物（NONO-coxibs），其将O₂-乙酰氧基甲基-1-(N-乙基-N-甲基氨基)重氮-1-鎓-1,2-二醇盐型NO供体基团，直接连接至1-(4-氨基磺酰苯基)-5-芳基-1H-吡唑-3-羧酸（6a-c）的羧基基团上。在pH 7.4（波动范围：7.97~8.51）的磷酸盐缓冲液（phosphate buffered saline，PBS）中孵育时，化合物6a-c（重氮-1-鎓-1,2-二醇盐类化合物）仅释放少量一氧化氮；而当将该类重氮-1-鎓-1,2-二醇酯型前药置于大鼠血清中孵育时，一氧化氮释放百分比显著升高，可达理论双分子NO/母核杂合酯前药最大释放量的84.5%~85.05%。上述孵育实验结果表明，在体内经非特异性血清酯酶裂解后，NONO-coxibs类母核药物可同时释放一氧化氮与抗炎活性成分1-(4-氨基磺酰苯基)-5-(4-H、4-F或4-甲基苯基)-1H-吡唑-3-羧酸（4a-c）。母核化合物4a-c展现出良好的抗炎活性（ID₅₀=81.4~112.4 mg/kg 经口给药），其活性介于对照药物阿司匹林（ID₅₀=114.3 mg/kg 经口给药）与塞来昔布（ID₅₀=12.6 mg/kg 经口给药）之间。这类兼具抗炎与NO释放功能的杂合酯型前药（NONO-coxibs）为开发无溃疡性及/或心血管不良反应的抗炎药物提供了极具潜力的药物设计思路。