COX-2抑制剂戊地昔布的合成

目的:合成COX-2抑制剂戊地昔布.方法:以苯乙酸为起始原料,经酰氯化、傅克酰化生成二苯乙酮后,与盐酸羟胺反应生成肟,再环合,磺化,氨化得戊地昔布.结果:得到的产品经IR,1H-NMR,MS和元素分析,证明是戊地昔布.结论:本合成路线简化了操作步骤,缩短反应时间,提高了收率.     

The effect of mild and moderate hepatic impairment on the pharmacokinetics of valdecoxib, a selective COX-2 inhibitor

Purpose This study evaluated the effects of varying degrees of hepatic impairment on the pharmacokinetics and safety of valdecoxib following single and multiple dosing.Methods This was an open-label, randomised, parallel group study in 12 subjects with mild hepatic impairment (Child-Pugh Class A) and in 13 with moderate hepatic impairment (Child-Pugh Class B) matched for age, weight, sex, and smoking status; there were two control groups of 12 healthy volunteers, one for each study group. All subjects received a single dose of valdecoxib 20 mg on day 1 and valdecoxib 20 mg twice daily on days 4–7, followed by a single morning dose on day 8. Plasma concentrations of free (unbound) and total valdecoxib and its active hydroxylated metabolite (SC-66905) were measured following single and multiple dosing (day 1 and day 8). Additionally, all subjects received a single intravenous dose of lidocaine 60 mg during the pretreatment period to determine plasma concentrations of monoethylglycinexylidide (MEGX) as a marker of hepatic CYP3A4 activity.Results The mean apparent oral clearance of free valdecoxib in plasma at steady state decreased by 22–25% in those with mild to moderate impairment (corresponding to a 28–33% increase in the AUC of free valdecoxib and a 19–23% decrease in the AUC of total SC-66905). The mean free fraction of valdecoxib in plasma increased by 9–38%, resulting in a mean decrease in apparent oral clearance of total valdecoxib in plasma of 0–15% (corresponding to a 0–17% increase in the AUC of total valdecoxib). Individual AUCs for free valdecoxib and total SC-66905 did not correlate well with AUCs for MEGX, indicating that decreases in intrinsic clearance of valdecoxib in those with hepatic impairment could not solely be explained by decreased CYP3A4 expression in hepatic impairment.Conclusions In our small study sample, mild and moderate hepatic impairment appeared to have only a modest effect on valdecoxib and SC-66905 pharmacokinetics. The adjustment of valdecoxib dose or dosing regimen does not appear mandatory in subjects with mild or moderate hepatic impairment, although caution is necessary during treatment of these patients with valdecoxib.     

Pharmacokinetics and metabolism of a COX-2 inhibitor, valdecoxib, in mice.

The pharmacokinetics and metabolism of valdecoxib, a potent cyclooxygenase-2 selective inhibitor, were investigated in mice. Valdecoxib was extensively metabolized after a single 5 mg/kg oral administration of [(14)C]valdecoxib and elimination of unchanged drug was minor (less than 1%) in male and female mice. The total mean percentage of administered radioactive dose recovered was 99.8% in the male mice and 94.7% in the female mice. Sixteen metabolites were identified in mouse plasma, red blood cells, urine, and feces. The main phase I metabolic pathway of valdecoxib in mice involved the oxidation of the 5-methyl group to form the active hydroxymethyl metabolite M1. M1 was further oxidized to the carboxylic acid metabolite M4, which underwent opening of the isoxazole ring to form M6 and M13. Phase II metabolism included glucuronide, glucoside, and methyl sulfone conjugations. M1 was also conjugated with glucuronic acid and glucose to yield M-G and M1-glucose, respectively. Three novel methylsulfone conjugates M20, M21, and M21-G were detected in blood or urine. Valdecoxib and M1 were the major radioactive components in plasma and red blood cells. The plasma area under the curve from zero to infinity (AUC(0-infinity)) values for valdecoxib and M1 were 3.58 and 0.850 microg. h/ml in males and 2.08 and 1.63 microg. h/ml in females, respectively. The RBC AUC(0-infinity) values for valdecoxib and M1 were 12.1 and 22.6 microg. h/g in males and 6.42 and 35.2 microg. h/g in females, respectively.     

Nonsteroidal anti-inflammatory drugs versus selective COX-2 inhibitors in the upper gastrointestinal tract

There are enough basic data supporting the use of coxibs with regard to the upper GI tract in patients with the need for continuous treatment of joint pain. The clinical studies available clearly show that coxibs induce fewer lesions and complications in volunteers and in patients when compared with NSAIDs. However, in Helicobacter pylori- positive patients the advantage seems less clear. The combination of NSAID plus PPI is not worse with regard to duodenal ulcers and recurrent clinical complications and is more cost effective than the use of coxibs. Similarly, with the concomitant use of aspirin even in low doses no major advantage of coxibs has been demonstrated. The combination of coxibs and PPI in high-risk patients needs to be studied. It is unclear at the moment how important are the changes in the lower GI tract. Considering the current controversy regarding cardiovascular events, there is no major reason to prefer coxibs to conventional NSAID plus PPI in patients needing long-term treatment.     

The COX-2 selective inhibitor,valdecoxib, does not impair platelet function in the elderly: results of a randomized controlled trial

The effects of the new cyclooxygenase (COX)-2 selective inhibitor, valdecoxib (40 mg bid; n = 17), on platelet function were evaluated, along with ibuprofen (800 mg tid; n = 15) and placebo (n = 15), in healthy elderly subjects (65-85 years) in this 7.5-day, randomized, single-center, double-blind study. Platelet aggregation (to sodium arachidonate, collagen, and adenosine diphosphate), bleeding time, and serum thromboxane B2 (TxB2) concentrations were measured up to 8 hours postdose on Days 1 and 8. Valdecoxib had no platelet effects, while ibuprofen significantly decreased platelet aggregation, significantly increased bleeding time (2-4 h postdose on each day), and significantly decreased TxB2 levels at all time points. In conclusion, unlike ibuprofen, valdecoxib 40 mg bid spares platelet COX-1 function in healthy elderly subjects. Valdecoxib's lack of effect on platelet aggregation and bleeding time suggests that it will have an improved clinical profile over nonselective NSAIDs, particularly in patients for whom bleeding complications are a concern.     

Rofecoxib: a selective COX-2 inhibitor

Drugs & Therapy Perspectives -     

Clinical pharmacology of celecoxib, a COX-2 selective inhibitor

NSAIDs are extensively used worldwide; nonetheless, they are associated with adverse gastrointestinal (GI) effects. COX-2 inhibitors (coxibs) have been developed to reduce pain and inflammation without associated GI and bleeding risks. Celecoxib was the first COX-2 inhibitor introduced on the market, and it still remains so, whereas rofecoxib and valdecoxib were withdrawn due to excess cardiovascular (CV) risk. There is consequently a concern that CV toxicity reflects a class effect of all COX-2 inhibitors. Celecoxib possesses anti-inflammatory and analgesic properties, and the evidence for CV risk is rather small and comparable to that of other traditional NSAIDs in short-term treatments (of < 4 weeks). It could be suggested that the use of low doses of celecoxib (100 mg b.i.d.) in short-treatment, especially in patients with previous experience of GI events and the recommendation of avoiding use of celecoxib in patients with CV history or risk, contribute in the decision-making process of prescribing COX-2 or NSAIDs.     

Characterization of etoricoxib,a novel,selective COX-2 inhibitor

Etoricoxib is a potent selective COX-2 inhibitor in man. Ex vivo whole-blood assays assessed COX-2 inhibition after oral administration of etoricoxib in single (5-500 mg) and multiple (25-150 mg) once-daily doses to healthy human subjects. A separate study examined ex vivo gastric mucosal PGE2 synthesis after etoricoxib (120 mg qd), naproxen (500 mg bid), or placebo for 5 days. The effect of etoricoxib 120 mg qd on the COX-1-mediated antiplatelet effects of low-dose aspirin (ASA) was also assessed. The mean (time)-weighted average inhibition (WAI) of lipopolysaccharide (LPS)-stimulated PGE2 (COX-2 assay) vcrsus placebo was dose related after single (range: 3.1%-99.1%) and multiple doses (range: 52.5%-96.7%). PGE2 remained significantly inhibited 24 hours postdose at steady state. Inhibition of LPS-stimulated PGE2 showed a strong relationship with etoricoxib plasma concentrations; ex vivo, IC50 was almost identical to in vitro. Multiple dosing of etoricoxib (up to 150 mg qd) showed no important effects on serum TXB2, bleeding time, or platelet aggregation (COX-1-mediated effects). The nonselective nonsteroidal anti-inflammatory (NSAID) naproxen significantly inhibited (approximately 78%) ex vivo prostaglandin synthesis in gastric mucosa; etoricoxib had no effect. Etoricoxib did not interfere with the antiplatelet effects of low-dose ASA, as assessed by serum TXB2 and platelet aggregation. Etoricoxib was generally well tolerated, even at doses above the clinical dose range. Based on these results, etoricoxib is a potent selective inhibitor of COX-2 after single and multiple dosing regimens and does not inhibit prostaglandin synthesis in the gastric mucosa, even at doses above the clinical dose range of 60 to 120 mg.     

Helicobacter pylori attenuates the delay in ulcer healing induced by aspirin and selective COX-2 inhibitor

Helicobacter pylori (H. pylori) and NSAIDs are recognized as major pathogenic factors in peptic ulcer disease. However, whether these two factors exert synergistic or antagonistic effects on ulcer healing has not yet been fully explained. In this study, the effects of aspirin (ASA) alone and rofecoxib, a specific prostaglandin cyclooxygenase (COX)-2 inhibitor, were compared with that of ASA and rofecoxib applied in combination with H. pylori on gastric acid secretion and healing of acetic acid ulcers in rats. The H. pylori colonization of gastric mucosa was determined by viable bacterial culture and histology. The area of ulcers was determined by planimetry, the gastric blood flow (GBF) was measured using the H₂-gas clearance method and the gastric mucosal generation of PGE₂ and plasma gastrin levels were assessed by radioimmunoassay. ASA or rofecoxib applied alone delayed significantly the healing of chronic gastric ulcers and this effect was accompanied by a marked decrease in the GBF at the ulcer margin and gastric mucosal PGE₂ generation without significant influence of gastric acid output. H. pylori that produced moderate gastric inflammation at the ulcer margin as confirmed by bacterial culture, prolonged significantly the healing of these ulcers and decreased the GBF at the ulcer margin and gastric acid output while elevating significantly the gastric mucosal PGE₂ generation and plasma gastrin levels. H. pylori attenuated significantly the ASA- and rofecoxib-induced inhibition of ulcer healing and accompanying fall in the GBF at the ulcer margin and reversed, in part, the ASA- and rofecoxib-induced alterations in PGE₂ generation. We conclude that H. pylori attenuates the delay in ulcer healing induced by ASA and rofecoxib due to enhancement in the generation of endogenous PGE₂ and gastrin release, as well as suppression of acid secretion which may limit deleterious influence of NSAID on ulcer healing.     

选择性COX-2抑制剂NS-398的制备

目的制备选择性COX-2抑制剂NS-398。方法以2-氟硝基苯为起始原料,经4步反应化合成化合物NS-398。结果与结论用该方法可以在温和条件下合成出该药,最终产品纯度大于99%。     

Cyclooxygenase (COX)-2 selective inhibitors: aspirin, a dual COX-1/COX-2 inhibitor, to COX-2 selective inhibitors

Aspirin was developed as a non-steroidal anti-inflammatory drug (NSAID) in 1899. During the century after that, aspirin has been found to show its anti-inflammatory, analgesic and anti-pyretic activities by reducing prostaglandins biosynthesis through inhibition of cyclooxygenase (COX); and then COX was found to be constituted of two isoforms, constitutive COX-1 and inducible COX-2. Currently, novel NSAIDs, acting through selective inhibition of COX-2, that have efficacy as excellent as aspirin with significantly lower incidence of gastrointestinal adverse effects are available in America and some other countries, but not in Japan. Physiological and pathophysiological roles of COX-1 and COX-2 have been explained from studies in experimental animals, but there are many differences in species and diseases between animals and humans. Thus, physiological and pathophysiological roles of COX-2 were considered from the standpoint of clinical effects of the two latest COX-2 selective inhibitors, celecoxib and rofecoxib, on inflammation, pain, fever and colorectal cancer together with their adverse effects on gastrointestinal, renal and platelet functions; and the usefulness and limits of COX-2-selective inhibitors were discussed with the trends of new NSAIDs development.     

Utility and sensitivity of the sore throat pain model: results of a randomized controlled trial on the COX-2 selective inhibitor valdecoxib

The sore throat pain model was employed in this randomized, placebo-controlled trial to examine the sensitivity of the model in testing the efficacy of valdecoxib as an acute analgesic drug. Changes were made to the study design by employing a different diagnostic index for tonsillo-pharyngitis, a different rating scale (derived from Lasagna's pain thermometer), and alternative analyses, individual responder rates. Under double-blind conditions, 197 patients with painful pharyngitis were randomly allocated to valdecoxib 20 mg bid (n = 65), valdecoxib 40 mg qd (n = 66), or placebo (n = 66) for 24 hours. The expanded Tonsillo-Pharyngitis Assessment and the Lasagna Pain Scale were validated as sensitive study instruments. Both dosage regimens provided significantly greater pain relief compared with placebo on standard efficacy measures over the 24-hour study (all P < .05). Tests for individual response (eg, percentage of patients with at least moderate relief) confirmed these results, and other response rates identified the high sensitivity of the model itself (eg, only 5% of placebo-treated patients achieved >or=50% of maximum total pain relief over 6 hours). These findings indicate that sore throat is a sensitive model to assess analgesic efficacy.     

Meta-analysis: upper gastrointestinal tolerability of valdecoxib, a cyclooxygenase-2-specific inhibitor, compared with nonspecific nonsteroidal anti-inflammatory drugs among patients with osteoarthritis and rheumatoid arthritis

AIM: To compare the incidence of abdominal pain, dyspepsia and/or nausea associated with valdecoxib, nonspecific nonsteroidal anti-inflammatory drugs and placebo in patients with rheumatoid arthritis and osteoarthritis. METHODS: Data from five randomized, double-blind 12-week trials were pooled. Independent risk factors for abdominal pain, dyspepsia and/or nausea were also determined. RESULTS: The final analysis consisted of 4394 patients. Nonspecific nonsteroidal anti-inflammatory drug users (n = 1185) received naproxen 1000 mg/day (n = 766), ibuprofen 2400 mg/day (n = 207) or diclofenac sodium 150 mg/day (n = 212). Valdecoxib users received 10 mg/day (n = 955), 20 mg/day (n = 851) or 40 mg/day (n = 430). A total of 973 patients received placebo. The nonspecific nonsteroidal anti-inflammatory drug group was most likely to report abdominal pain or dyspepsia, while the placebo group reported the highest incidence of nausea. The most important risk factors for abdominal pain, dyspepsia and/or nausea were nonspecific nonsteroidal anti-inflammatory drug use, gastrointestinal history of nonspecific nonsteroidal anti-inflammatory drug-related intolerance or gastroduodenal ulcers, osteoarthritis diagnosis, female gender and age <65 years. CONCLUSION: This pooled analysis demonstrates a clear decrease in dyspepsia and an improvement in upper gastrointestinal tolerability for patients with osteoarthritis and rheumatoid arthritis taking valdecoxib, even at supratherapeutic doses, compared with those taking nonspecific nonsteroidal anti-inflammatory drugs over 12 weeks.     

COX-2 inhibition, H. pylori infection and the risk of gastrointestinal complications

Current data on the gastric safety of cyclooxygenase-2 (COX-2) inhibitors in the presence of H. pylori infection are largely derived from animal experiments and indirect clinical evidence. In animal models of H. pylori gastritis, COX-2 inhibitors suppressed prostaglandin synthesis and aggravated mucosal damage. In the human stomach, COX-1 appears to be the predominant source of prostaglandins despite the fact that COX-2 is upregulated in H. pylori gastritis. There are conflicting data on whether H. pylori alters the risk of ulcer in patients receiving COX-2 inhibitors. Among patients with H. pylori infection, rofecoxib reduced the risk of complicated gastric but not duodenal ulcers as compared to naproxen. The advantage of rofecoxib over naproxen also disappeared in patients with H. pylori infection and prior upper gastrointestinal events. In contrast, pooled data suggested that H. pylori increases the risk of ulcer in patients receiving nonselective nonsteroidal anti-inflammatory drugs but not in patients receiving celecoxib. In rodent gastric ulcers, COX-2 was upregulated in the granulation tissue and ulcer margin. Inhibition of COX-2 delayed healing of experimental gastric ulcer. Limited data showed that COX-2 expression was also increased in human gastric ulcer regardless of the H. pylori status. The functional significance of COX-2 in human gastric ulcer is unknown.     

Etodolac: An overview of a selective COX-2 inhibitor

Etodolac is a non-steroidal anti-inflammatory drug (NSAID) which has been shown to be effective in the treatment of rheumatoid arthritis and osteoarthritis and a selective COX-2 inhibitor in a wide range of clinically relevant assays in direct comparisons with other NSAIDs. Studies have shown etodolac to have no overall suppression of gastric or duodenal prostaglandins and endoscopic analysis with etodolac showed placebo level scores in comparison with ibuprofen, which showed inducement of gastro-intestinal (GI) side effects. This high degree of gastric tolerability was further demonstrated by microbleeding studies. The favourable GI tolerability profile of etodolac has been shown in long-term and large-scale trials and by routine clinical observation. In summary, etodolac is a well established selective COX-2 inhibitor that has been shown not to suppress gastric or duodenal prostaglandins, to have minimal hepatic or renal effects and to have favourable GI tolerability in comparison with ibuprofen.     

Sweet's syndrome associated with the intake of a selective cyclooxygenase-2 (COX-2) inhibitor

Sweet's syndrome (SS; acute febrile neutrophilic dermatosis) is a skin disorder characterized by acute tender erythematous plaques or nodules that may blister and ulcerate. The disease presents in several clinical settings including: classical (idiopathic) SS, malignancy-associated SS and drug-induced SS. Several drugs have been implicated in the etiopathogenesis of the disease with the most frequent being the granulocyte-colony stimulating factor. We report and discuss a case of SS associated with the intake of a selective cyclooxygenase-2 inhibitor, which has been rarely reported.     

Meloxicam: a selective COX-2 inhibitor non-steroidal anti-inflammatory drug

Meloxicam is a new non-steroidal anti-inflammatory drug (NSAID) that selectively inhibits the inducible isoform of the cyclo-oxygenase (COX)-2 enzyme. This enzyme has a major role in mediating the inflammatory response, while synthesis of prostaglandins required for normal physiological functioning of the stomach and kidneys is under the control of the constitutive isoform, COX-1. Other NSAIDs in clinical use show varying degrees of selectivity towards COX-1. Only meloxicam and (albeit to a lesser extent) nimesulide could be described as selective for COX-2. In comparative trials of patients with osteo- and rheumatoid arthritis, meloxicam has been found to be at least as effective as other NSAIDs, but with a greatly reduced incidence of gastrointestinal side-effects. There is no evidence that meloxicam causes any deterioration in renal function in patients with moderate degrees of renal failure, and no evidence of drug accumulation with continued use. Meloxicam's half-life of 20 h makes it ideal for once daily administration, and it is 99% converted to inactive metabolites prior to excretion. No clinically significant drug interactions have been detected, making it suitable for use in patients with co-existing pathology. Meloxicam's safety and tolerability make it a significant advance in the treatment of rheumatic disease.