Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used because of their anti-inflammatory and analgesic activity. It is commonly recognized that NSAIDs exert their effect by blocking the activity of cyclooxygenase (COX), also known as prostaglandin G/H synthase (PGHS), the enzyme that converts arachidonic acid into prostanoids. Inhibition of the biosynthesis of prostanoids, the mediators of pain, fever, and inflammation, has long been a therapeutic target of anti-inflammatory drug discovery. The therapeutic use of conventional NSAIDs is limited by drug-associated side effects, such as severe gastric ulceration, bleeding and renal toxicity.
Two forms of COX have been identified, a constitutive isoform (COX-1), and an inducible isoform (COX-2), of which expression is upregulated at sites of inflammation (see Vane, J R; Mitchell, J A; Appleton, I; Tomlinson, A et al., Proc. Nat'l. Acad. Sci. USA, 1994, 91, 2046). COX-1 is believed to play a physiological role in gastrointestinal and renal protection, while COX-2 appears to play a predominant pathological role in inflammatory conditions. The NSAIDs currently on the market inhibit both COX-1 and COX-2 isoforms with little variation in selectivity, explaining the beneficial (inhibition of COX-2) and harmful (inhibition of COX-1) effects. The selective inhibition of COX-2 has been a goal of drug developers. It is thought that this will reduce or eliminate the GI irritation caused by COX-1 inhibition.
The differential tissue distribution of COX-1 and COX-2 provides a basis for the development of drugs that are selective COX-2 inhibitors, such that the specificity for the inhibition of COX-2 far exceeds inhibition of COX-1 (see Meade, Smith, and DeWift, J. Biol. Chem. (1993) 268:6610-6614)). Detailed structure-activity relationship studies have been reported for two general structural classes of selective COX-2 inhibitors, including certain acidic sulfonamides and diarylheterocyclics. The in vivo activities of these selective COX-2 inhibitors support the hypothesis that selective COX-2 inhibition is anti-inflammatory and non-ulcerogenic (see Gans, Galbraith, Roman, Haber, Kerr, Schmidt, Smith, Hewes, and Ackerman, “Anti-Inflammatory and Safety Profile of DuP 697, a Novel Orally Effective Prostaglandin Synthesis Inhibitor”, J. Pharmcol Exp. Ther. (1990) Vol. 254, pp. 180-187; Penning, Talley, Bertenshaw, Carter, Collins, Docter, Graneto, Lee, Malecha, Miyashiro, Rogers, Rogier, Yu, Anderson, Burton, Cogburn, Gregory, Koboldt, Perkins, Seibert, Veenhuizen, Zhang, and Isakson, “Synthesis and Biological Evaluation of the 1,5-Diarylpyrazole Class of Cyclooxygenase-2 Inhibitors: Identification of 4-[5-(4-Methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamide (SC-58635, Celecoxib)”, J. Med. Chem. (1997) Vol. 40, pp. 1347-1365; Khanna, Weier, Yu, Xu, Koszyk, Collins, Koboldt, Veenhuizen, Perkins, Casler, Masferrer, Zhang, Gregory, Seibert, and Isakson, “1,2-Diarylimidazoles as Potent Cyclooxygenase-2 Selective, and Orally Active Antiinflammatory Agents”, J. Med. Chem. (1997) Vol. 40, pp. 1634-1647; Khanna, Weier, Yu, Collins, Miyashiro, Koboldt, Veenhuizen, Curie, Siebert, and Isakson, “1,2-Diarylpyrroles as Potent and Selective Inhibitors of Cyclooxygenase-2”, J. Med. Chem. (1997) Vol. 40, pp. 1619-1633; Tsuji, Nakamura, Konishi, Tojo, Ochi, Senoh, and Matsuo, “Synthesis and Pharmacological Properties of 1,5-Diarylyrazoles and Related Derivatives”, Chem. Pharm. Bull. (1997) Vol. 45, pp. 987-995; Riendeau, Percival, Boyce, Brideau, Charleson, Cromlish, Ethier, Evans, Falgueyret, Ford-Hutchinson, Gordon, Greig, Gresser, Guay, Kargman, Leger, Mancini, O'Neill, Quellet, Rodger, Therien, Wang, Webb, Wong, Xu, Young, Zamboni, Prasit, and Chan, “Biochemical and Pharmacological Profile of a Tetrasubstituted Furanone as a Highly Selective COX-2 Inhibitor”, Br. J. Pharmacol. (1997) Vol. 121, pp. 105-117; Roy, Leblanc, Ball, Brideau, Chan, Chauret, Cromlish, Ethier, Gauthier, Gordon, Greig, Guay, Kargman, Lau, O'Neill, Silva, Therien, Van Staden, Wong, Xu, and Prasit, “A New Series of Selective COX-2 Inhibitors: 5,6-Diarylthiazolo[3,2-b][1,2,4]-triazoles”, Bioorg. Med. Chem. Lett. (1997) Vol. 7, pp. 57-62; Therien, Brideau, Chan, Cromlish, Gauthier, Gordon, Greig, Kargman, Lau, Leblanc, Li, O'Neill, Riendeau, Roy, Wang, Xu, and Prasit, “Synthesis and Biological Evaluation of 5,6-Diarylimidazo[2.1-b]thiazoles as Selective COX-2 Inhibitors”, Bioorg. Med. Chem. Lett. (1997) Vol. 7, pp. 47-52; Li, Norton, Reinhard, Anderson, Gregory, Isakson, Koboldt, Masferrer, Perkins, Seibert, Zhang, Zweifel, and Reitz, “Novel Terphenyls as Selective Cyclooxygenase-2 Inhibitors and Orally Active Anti-Inflammatory Agents”, J. Med. Chem. (1996) Vol. 39, pp. 1846-1856; Li, Anderson, Burton, Cogburn, Collins, Garland, Gregory, Huang, Isakson, Koboldt, Logusch, Norton, Perkins, Reinhard, Seibert, Veenhuizen, Zhang, and Reitz, “1,2-Diarylcyclopentenes as Selective Cyclooxygenase-2 Inhibitors and Orally Active Anti-Inflammatory Agents”, J. Med. Chem. (1995) Vol. 38, pp. 4570-4578; Reitz, Li, Norton, Reinhard, Huang, Penick, Collins, and Garland, “Novel 1,2-Diarylcyclopentenes are Selective Potent and Orally Active Cyclooxygenase Inhibitors”, Med. Chem Res. (1995) Vol. 5, pp. 351-363; Futaki, Yoshikawa, Hamasaka, Arai, Higuchi, lizuka, and Otomo, “NS-398, A Novel Nonsteroidal Antiinflammatory Drug with Potent Analgesic and Antipyretic Effects, which Causes Minimal Stomach Lesions”, Gen. Phamacol. (1993) Vol. 24, pp. 105-110; Wiesenberg-Boetcher, Schweizer, Green, Muller, Maerki, and Pfeilschifter, “The Pharmacological Profile of CGP 28238, A Novel Highly Potent Anti-Inflammatory Compound”, Drugs Exptl Clin Res. (1989) Vol. XV, pp. 501-509; Futaki, Takahashi, Yokoyama, Arai, Higuchi, and Otomo, “NS-398, A New Anti-Inflammatory Agent, Selectively Inhibits Prostaglandin G/H Synthase/Cyclooxygenase (COX-2) Activity in vitro”, Prostaglandins (1994) Vol. 47, pp. 55-59; Klein, Nusing, Pfeilschifter, and Ullrich, “Selective Inhibition of Cyclooxygenase-2”, Biochem. Pharmacol. (1994) Vol. 48, pp. 1605-1610; Li, Black, Chan, Ford-Hutchinson, Gauthier, Gordon, Guay, Kargman, Lau, Mancini, Quimet, Roy, Vickers, Wong, Young, Zamboni, and Prasit, “Cyclooxygenase-2 Inhibitors. Synthesis and Pharmacological Activities of 5-Methanesulfonamido-1-indanone Derivatives”, J. Med. Chem. (1995) Vol. 38, pp. 4897-8905; Prasit, Black, Chan, Ford-Hutchinson, Gauthier, Gordon, Guay, Kargman, Lau, Li, Mancini, Quimet, Roy, Tagari, Vickers, Wong, Young, and Zamboni, “L-745,337: A Selective Cyclooxygenase-2 Inhibitor”, Med. Chem. Res. (1995) Vol. 5, pp. 364-374; Tanaka, Shimotori, Makino, Aikawa, Inaba, Yoshida, and Takano, “Pharmacological Studies of the New Antiinflammatory Agent 3-Formylamino-7-methylsulfonylamino-6-phenoxy-4H-1-benzopyran-4-one. 1st Communication: Antiinflammatory, Analgesic and Other Related Properties”, Arzniem.-Forsch./Drug Res. (1992) Vol. 42, pp. 935-944; Nakamura, Tsuji, Konishi, Okumura, and Matsuo, “Studies on Anti-Inflammatory Agents. I. Synthesis and Pharmacological Properties of 2′-(phenylthio)methanesulfonamides and Related Derivatives”, Chem. Pharm. Bull. (1993) Vol. 41, pp. 894-906; Chan, Boyce, Brideau, Ford-Hutchinson, Gordon, Guay, Hill, Li, Mancini, Penneton, Prasit, Rasori, Riendeau, Roy, Tagari, Vickers, Wong, and Rodger, “Pharmacology of a Selective Cyclooxygenase-2 Inhibitor, L-745,337: A Novel Nonsteroidal Anti-Inflammatory Agent with an Ulcerogenic Sparing Effect in Rat and Nonhuman Primate Stomach”, J. Pharmacol. Exp. Ther. (1995) Vol. 274, pp. 1531-1537.
There are only a few reports of attempts to convert NSAIDs that are non-selective COX inhibitors into selective COX-2 inhibitors. (See, Black, Bayly, Belley, Chan, Charleson, Denis, Gauthier, Gordon, Guay, Kargman, Lau, Leblanc, Mancini, Quellet, Percival, Roy, Skorey, Tagari, Vickers, Wong, Xu, and Prasit, “From Indomethacin to a Selective COX-2 Inhibitor: Development of Indolalkanoic Acids as Potent and Selective Cyclooxygenase-2 Inhibitors”, Bioorg. Med. Chem. Lett. (1996) Vol. 6, pp. 725-730; Luong, Miller, Barnett, Chow, Ramesha, and Browner, “Flexibility of the NSAID Binding Site in the Structure of Human Cyclooxygenase-2”, Nature Structural Biol. (1996) Vol. 3, pp. 927-933; and Kalgutkar, Crews, Rowlinson, Garner, Seibert, and Marnett, “Aspirin-Like Molecules that Covalently Inactivate Cyclooxygenase-2”, Science (1998) Vol. 280, pp. 1268-1270).
Efforts in drug development have focused on the biochemical conversion of various NSAIDs. Ashton et al., in U.S. Pat. No. 5,681,964, discloses conversion of indomethacin (an NSAID) into certain ester derivatives with concomitant reduction of GI irritation. U.S. Pat. Nos. 5,607,966 and 5,811,438 disclose conversion of indomethacin into certain ester derivatives and amide derivatives (which are useful as antioxidants and inhibitors of 5-lipoxygenase), but do not address COX-2 selective inhibition. U.S. Pat. Nos. 3,285,908, 3,336,194 describe secondary and tertiary amide derivatives of indomethacin, but fail to address COX inhibition. In addition, COX-2 selective inhibitors 1-aroyl-3-indolyl alkanoic acids and N-benzyl-3-indoleacetic acids are described in U.S. Pat. Nos. 5,436,265 and 5,510,368.
Various compounds have been used as starting points in the design of selective COX-2 inhibitors, including NSAIDs, (1) that are selective COX-1 inhibitors or (2) that have essentially the same inhibitory activity for both COX-1 and COX-2. The conformational analysis of the human COX-2 crystal structure suggests that creating a wide range of analogs of COOH-containing NSAIDs, each with a different functional group replacing the OH of the COOH, could improve water-solubility, bioavailability, or pharmacokinetics. Kolasa et al. and Flynn et al. attempted to replace the carboxylic acid group in NSAIDs with a hydroxamic acid moiety or a hydroxyurea moiety and achieved dual inhibition of COX and 5-lipoxygenase. However, none of the analogs displayed any significant selective COX-2 inhibition, with the hydroxamates undergoing facile hydrolysis (see Kolasa, Brooks, Rodriques, Summers, Dellaria, Hulkower, Bouska, Bell, and Carter, “Nonsteroidal Anti-Inflammatory Drugs as Scaffolds for the Design of 5-Lipoxygenase Inhibitors”, J. Med. Chem. (1997) Vol. 40, pp. 819-824; and Flynn, Capiris, Cetenko, Connor, Dyer, Kostlan, Niese, Schrier, and Sircar, “Nonsteroidal Antiinflammatory Drug Hydroxamic Acids. Dual Inhibitors of Both Cyclooxygenase and 5-Lipoxygenase”, J. Med. Chem. (1990) Vol. 33, pp. 2070-2072.)
The generation of selective COX-2 analogues of indomethacin and meclofenamic acid via amidation or esterification has been described in U.S. Pat. No. 6,399,647. More recently the metabolism of one such indomethacin amide analogue was published and was reported to be rapidly metabolized by human liver microsomes (Remmel R P et al., Drug Metab Dispos 32:113-122, 2004). Thus, new compositions are needed that are selective COX-2 inhibitors and that have improved therapeutic properties, including pharmacokinetics. Simple methods for preparing and using such compositions are also needed.