药物临床试验计算机仿真简介

本文综述了药物临床试验计算机仿真的发展、设计及应用。从药代动力学、药效动力学的角度介绍了药物临床试验计算机仿真,进而根据国外药物临床试验的计算机仿真情况分析了仿真设计的基本方法以及模型计算和软件,最后讨论了药物临床试验计算机仿真的研究应用。     

药物与血浆蛋白结合的药理学基础及其研究进展

体内各种因素引起的药物与血浆蛋白结合的改变,可能导致相应的药代动力学参数变化。本文综述了有关药物 血浆蛋白结合的基础理论和研究方法进展,及其与药代动力学和药效相关性的理论阐述,并运用药理学相关基础理论对其临床意义进行了深入的探讨,总结了在常规的药物实践中如何评价药物的游离浓度监测和血浆蛋白结合的药效和临床相关性研究。     

新结构类型环氧化酶-2抑制剂的研究进展

非甾体抗炎药环氧化酶-2(COX-2)选择性抑制剂的应用已超过百年历史,近年来发现部分COX-2选择性抑制剂引起较为严重的心血管不良反应(如卒中、心肌梗死等),限制了其临床应用.因此,寻找更加安全、有效的新结构类型的COX-2选择性抑制剂已成为非甾体抗炎药的研究热点.文中通过文献调研,综述近年来利用人工合成、药效团筛选、天然产物提取分离得到的COX-2选择性抑制剂的研究进展.     

对药远志-天麻中GABA-AT靶点抑制活性物质的虚拟筛选

目的 对对药远志-天麻中潜在作用于GABA转氨酶(GABA aminotransferase, GABA-AT)靶点的抗癫痫活性物质进行研究,阐明其药效物质基础。方法 收集文献中具有抑制GABA-AT活性的化合物信息,建立基于GABA-AT配体的HipHop药效团模型,收集文献中远志与天麻中的成分并建立化合物库,对远志与天麻中的成分与药效团进行匹配,采用柔性对接手段对匹配到的小分子化合物与GABA-AT靶点(PDB ID:1OHW)进行对接并评估其相互作用,采用体外酶活力法初步评价筛选到单体的GABA-AT的抑制活性。结果 通过文献检索共得到远志与天麻中化学成分26种,通过测试集验证选出优选药效团3用于对远志与天麻化合物库的虚拟筛选,匹配后得到10种远志与天麻中潜在的GABA-AT抑制成分。通过分子模拟对接分析了10种化合物对GABA-AT的作用情况,对其中4种单体进行了酶活力抑制能力评估。结论 基于药效团及分子模拟对接手段探讨远志与天麻中GABA-AT抑制成分具有一定的准确性。     

HIV蛋白酶抑制剂帕利那韦在大鼠体内的药代动力学

目前,尚无合适的动物模型用于HIV蛋白酶抑制剂的药效学评价,因而药代动力学参数成为筛选药物的重要依据。帕利那韦(pali-navir)在体外具有抑制HIV-1和HIV-2蛋白酶的活性,是一个有前途的治疗艾滋病候选药,因而对其药代动力学进行了研究。实验用雄性Sprague-Dawley大鼠,给药途径和剂量分别为口服:2,3,5,10和20mg.kg-1;静注:1,2,3和5mg.kg-1;十二指肠内给药:2,3和5mg.kg-1。最后将实验的结果与其他HIV蛋白酶抑制剂的动力学参数进行比较并推测帕利那韦在胃中降解的可能性。实验结果显示,静脉给药的AUC与给药剂量不成比例,平均生物半衰期…     

基于HDAC的双靶点抗肿瘤药物研究进展

多靶点作用的抗肿瘤药物比目前单靶点药物具有更好的药效,且能够降低耐药性和毒副作用。为了探索多靶点药物在肿瘤化疗中的应用前景,以组蛋白去乙酰化酶(HDAC)抑制剂为基础设计多种作用的双靶点抑制剂已经成为了研究热点,其中部分化合物抑制肿瘤细胞增殖活性比现有的上市药物更好。本文综述了基于HDAC的双靶点抑制剂的研究进展,重点介绍了作用机制、设计策略和生物活性。     

计算模拟技术在化合物代谢特征预测中的应用

近年来已经发现,具有良好的药代动力学特征的候选药物方有临床应用价值和前景,因此在新药研发的过程中应尽早引入对药物吸收、分布、代谢和排泄的评价。细胞色素P450（CYP450）是药物体内代谢中一类至关重要的酶系,若能较准确地对化合物的CYP450代谢特征,如其是否为CYP450的底物、抑制剂和诱导剂等进行预测,就有可能提高新药研发的成功率,故以此为例,介绍目前有关计算模拟技术在预测化合物代谢特征方面的应用研究进展。     

环氧酶抑制类药的抗炎抗风湿作用

环氧酶(Cyclooxygenase,COX)又称前列腺素内过氧化物合物是花生四烯酸代谢途径的关键酶之一。在体内环氧酶至少存在两种亚型:COX-1和COX-2。COX-1在大多数组织中稳定表达,而COX-2在受到多种刺激后可在局部组织中诱导表达。已经证明,COX-2与急慢性炎症、关节炎、发热、疼痛、肿瘤以及Alzheimer症等疾病的发生、发展密切相关。临床研究表明COX-2选择性抑制剂可以在有效抑制炎症的同时较少发生胃肠不良反应。在本论文研究中我们首次建立了利用内源性花生四烯酸的基于小鼠腹腔巨噬细胞的COX-1和COX-2体外筛选模型,该模型实现了在同一种细胞上同时获得化合物对COX-1和COX-2的抑制活性,适合于化合物初步体外评价和构效关系分析。A23187可剂量依赖的刺激小鼠腹腔巨噬细胞释放大量6-keto-PGF1α,其水平可反映COX-1活性:LPS能以时间和剂量依赖的方式诱导小鼠腹腔巨噬细胞释放PGE2,COX-2 mRNA的积累与PGE2更多还原。     

第二代COX-2抑制剂

第二代COX-2抑制剂的选择性比第一代高数倍。用于治疗疼痛和炎症可获得显著疗效。本文介绍选择性COX-2抑制剂伐地考昔、帕瑞考昔和etoricoxib及lumiracoxib的药效学、药动学、临床评价和安全性。     

药物代谢动力学在药物研究中的应用与进展(下)

2药代动力学在新药开发阶段中的应用与进展先导化合物经过初步的筛选和结构优化得到候选化合物之后,就进入了药物的开发研究阶段。药物的开发阶段包括系统的临床前研究和临床研究。     

Cyclooxygenase-2 inhibitors: a literature and patent review (2009 - 2010)

INTRODUCTION: COXs catalyze the complex conversion of arachidonic acid to prostaglandins and thromboxanes, which trigger as autacoids with autocrine and paracrine biological effects many physiological and pathophysiological responses. The structural similarities of the COX-1 and -2 enzymes make the search for selective inhibitors for COX-2 versus -1 a formidable challenge. AREAS COVERED: The present review provides a survey of the development of novel COX-2 inhibitors covering literature and patents between 2009 and 2010. The presence of a central, typically 1,2-diaryl substituted, heterocycle or carbocycle as a characteristic structural motif in many selective COX-2 inhibitors represents the basis of their classification in this review. The classification in this review includes COX-2 inhibitors based on five- and six-membered heterocycles, benzoheterocycles (e.g., benzopyrans, benzopyranones, indoles and quinolines), quinones, chalcones, natural products and miscellaneous. When available, COX-2 inhibitors are presented with their related COX-2 inhibitory potency and selectivity. EXPERT OPINION: The availability of detailed information on the crystal structure of the COX-2 enzyme with various substrates, cofactors and inhibitors, and the recently reported increased risk of cardiovascular events associated with selective COX-2 inhibitors will further stimulate development of COX-2 inhibitors with favorable COX-2 inhibition profiles without adverse effects to the cardiovascular system.     

Imrecoxib： a novel and selective cyclooxygenase 2 inhibitor with anti-inflammatory effect

INTRODUCTION Cyclooxygenase (COX) is a rate-limiting enzymefor prostaglandin synthesis. Three isotypes of COXs(COX-1, COX-2, and COX-3) have been identified[1-2],though COX-3 activityinhuman has not beenconfirmed[3].COX-1 isconstitutivelyinvolved in actions suchas plate-let activation, gastrointestinal protection and kidneyfunction. COX-2 is primarilyproduced in response totissue damage andisinvolved in inflammatoryresponses.Traditional non-steroidal anti-inflammatory drugs…     

Comment and reply on: Atorvastatin: safety and tolerability

In a very short time, COX-2 enzyme inhibitors have gone from the darlings to the pariahs of the pharmaceutical industry. These drugs were developed based on the hypothesis whereby selective inhibition of the COX enzyme would lead to reduction in pain and inflammation without associated gastrointestinal and bleeding risks. However, in September 2004, rofecoxib was voluntarily removed from the market for increased cardiovascular risk and in April 2005, valdecoxib was also withdrawn, at least in part, due to excess cardiovascular risk. Celecoxib was the first COX-2 inhibitor introduced and the only remaining one on the US market. There is consequently a justified concern that cardiovascular toxicity is a class effect of all COX-2 inhibitors. This article systematically reviews the evidence surrounding COX-2 inhibitors and cardiovascular risk. Although the evidence suggests a fairly consistent cardiovascular risk with rofecoxib, the evidence for cardiovascular risk with celecoxib is more equivocal. Although isolated studies have suggested some cardiovascular risk for celecoxib, the totality of the evidence suggests that any risk is likely to be small and comparable to traditional NSAIDs. The cardiovascular risks of COX-2 inhibitors appear heterogeneous, influenced not only by the drug class, but also individual drug, dosage and patient characteristics. Specific modifying factors of the cardiovascular risk of COX-2 inhibitors including dose, concomitant drugs, individual cardiac and genetic risk profiles, will require further study.     

Cyclooxygenase-2 inhibitors: a literature and patent review (2009 – 2010)

Introduction: COXs catalyze the complex conversion of arachidonic acid to prostaglandins and thromboxanes, which trigger as autacoids with autocrine and paracrine biological effects many physiological and pathophysiological responses. The structural similarities of the COX-1 and -2 enzymes make the search for selective inhibitors for COX-2 versus -1 a formidable challenge.

Areas covered: The present review provides a survey of the development of novel COX-2 inhibitors covering literature and patents between 2009 and 2010. The presence of a central, typically 1,2-diaryl substituted, heterocycle or carbocycle as a characteristic structural motif in many selective COX-2 inhibitors represents the basis of their classification in this review. The classification in this review includes COX-2 inhibitors based on five- and six-membered heterocycles, benzoheterocycles (e.g., benzopyrans, benzopyranones, indoles and quinolines), quinones, chalcones, natural products and miscellaneous. When available, COX-2 inhibitors are presented with their related COX-2 inhibitory potency and selectivity.

Expert opinion: The availability of detailed information on the crystal structure of the COX-2 enzyme with various substrates, cofactors and inhibitors, and the recently reported increased risk of cardiovascular events associated with selective COX-2 inhibitors will further stimulate development of COX-2 inhibitors with favorable COX-2 inhibition profiles without adverse effects to the cardiovascular system.     

The second generation of COX-2 inhibitors: what advantages do the newest offer?

The discovery of two cyclooxygenase (COX)-isoenzymes, a constitutive COX-1, serving homeostatic prostanoid synthesis, and an inducible COX-2, responsible for proinflammatory prostanoid production, led to the development of new non-steroidal anti-inflammatory drugs (NSAIDs), the selective COX-2 inhibitors, promising minimal NSAID-typical toxicity with full anti-inflammatory efficacy. So far, the strategy of selective COX-2 inhibition has been successful. Selective COX-2 inhibitors have significantly less gastrotoxicity and no effects on platelet aggregation. However, with regard to renal adverse events, selective COX-2 inhibitors do not offer a clinically relevant advantage over non-selective inhibitors. Moreover, concerns over the cardiovascular risk of selective COX-2 inhibitors have recently been raised. The second generation of COX-2 inhibitors with higher COX-2 selectivity was developed with the promise of further reduction of NSAID-typical adverse effects. The leading compounds are valdecoxib, parecoxib, etoricoxib and lumaricoxib. At the present time they have proven efficacy for the treatment of pain and inflammation. Parecoxib as a parenteral, highly selective COX-2 inhibitor has the potential to become the NSAID of choice for treatment of postoperative pain. In clinical trials, valdecoxib, parecoxib, etoricoxib and lumaricoxib have caused no more endoscopic ulcers than placebo. However, to date, no data on the clinically relevant endpoints perforation, symptomatic ulcer and bleeding are available. Furthermore, no definite conclusions on renal and cardiovascular safety are possible. Current evidence points to a marginal, if any, gain of safety compared with the first generation of COX-2 inhibitors. However, trials with the new COX-2 inhibitors offer the chance to address these open questions of highly selective COX-2 inhibition; that is, thrombogenic risk, sodium and water retention, and interference with tissue repair, in particular, healing of mucosal damage.     

Synthesis and biologic evaluation of new 3-phenoxyazetidin-2-one derivatives as selective cyclooxygenase-2 inhibitors

A new series of 3-phenoxyazetidin-2-ones (β-lactams) were designed and synthesized for the evaluation as selective cyclooxygenase-2 (COX-2) inhibitors. In vitro COX-1 and COX-2 inhibition studies showed that all compounds were selective inhibitors of the COX-2 isozyme with IC₅₀ values in the 0.054–0.095 μM range, and COX-2 selectivity indexes in the 228.47–355.6 range. Among the synthesized compounds, 1-(4-methoxyphenyl)-4-(4-(methylsulfonyl)phenyl)-3-phenoxyazetidin-2-one (4j) possessing methoxy group at the para position of N-1 phenyl ring exhibited the highest COX-2 inhibitory selectivity and potency even more potent than the reference drug celecoxib. Molecular modeling studies indicated that the methylsulfonyl pharmacophore group can be inserted into the secondary pocket of COX-2 active site.     

Characterization of eltenac and novel COX-2 selective thiopheneacetic acid analogues in vitro and in vivo

We assessed the effect of novel selective thiopheneacetic acids on cyclooxygenase isoenzymes in vitro and in vivo. Thiopheneacetic acid Eltenac and derivatives were investigated in this study. In human whole blood experiments these derivatives were potent inhibitors of COX-2 (IC(50)=0.02-0.4 microM) with less pronounced effect on COX-1 (IC(50)=0.15-5.6 microM). With COX-1/COX-2 ratios between 7.5- and 16-fold they are in the range of Celecoxib (13-fold). The parent drug Eltenac demonstrated no selectivity for COX-2. In a rat paw edema model, these compounds showed reduction of edema volume in the range of 36-45% at 10 mg/kg (Eltenac 52%, Diclofenac 51%). However, the compounds were superior to Diclofenac and Eltenac with respect to their ulcerogenic and gastrointestinal properties. Introduction of a nitrate-ester moiety to either Eltenac or a derivative did neither improve selectivity or potency in vitro, nor ulcerogenicity in vivo. Molecular modeling of selective thiopheneacetic acid derivatives to the active site of human COX-2 suggested similar binding properties as Lumiracoxib and Diclofenac. In summary, modification of Eltenac generates moderately selective COX-2 drugs in the range of Celecoxib with respect to potency and selectivity. The drugs showed potent anti-inflammatory properties and significant improvement of animal survival in a sub-chronical experimental set up. Thiopheneacetic derivatives are characterized by low pK(a) values, short microsomal half-lives and binding mode to COX-2 similar to Diclofenac and Lumiracoxib. These properties may also have an impact on the transient inhibition of COX-2-dependent prostacyclin, thereby being less associated with vascular complications.     

NSAIDs and cardiovascular disease: transducing human pharmacology results into clinical read-outs in the general population

Traditional (t) non-steroidal anti-inflammatory drugs (NSAIDs) and selective cyclooxygenase (COX)-2 inhibitors (coxibs) are important and efficacious drugs for the management of musculoskeletal symptoms. These drugs have both beneficial and adverse effects due to the inhibition of prostanoids. Although the tNSAID and coxib inhibition of COX-2-dependent prostaglandin (PG)E2 production is effective in ameliorating symptoms of inflammation and pain, a small but consistent increased risk of myocardial infarction has been detected in association with their use. Convincing evidence suggests that cardiovascular toxicity associated with the administration of these compounds occurs through a common mechanism involving inhibition of COX-2-dependent prostacyclin. The development of biomarkers that predict the impact of NSAIDs on COX-1 and COX-2 activities in vitro, ex vivo and in vivo has been essential to read-out the clinical consequences of the varying degrees of inhibition of the two COX-isozymes in humans. Whole blood assays for COX-1 and COX-2 might be candidates as surrogate end-points of toxicity and efficacy of NSAIDs. Using a biomarker strategy, we have shown that the degree of inhibition of COX-2 and the functional selectivity with which it is achieved are relevant to the level of cardiovascular hazard from NSAIDs and relate to drug potency (exposure). We propose that the assessment of COX-2 in whole blood ex vivo, either alone or in combination with urinary levels of 2,3–dmor-6–keto-PGF_1a a biomarker of prostacyclin biosynthesis in vivo, may represent a valid surrogate end-point to predict cardiovascular risk for functionally selective COX-2 inhibitors.     

Design, synthesis and biological evaluation of new 5,5-diarylhydantoin derivatives as selective cyclooxygenase-2 inhibitors

A new group of 5,5-diarylhydantoin derivatives bearing a methylsulfonyl COX-2 pharmacophore at the para position of the C-5 phenyl ring were designed and synthesized as selective COX-2 inhibitors. In vitro COX-1/COX-2 inhibition structure-activity relationships identified 5-[4-(methylsulfonyl)phenyl]-5-phenyl-hydantoin (4) as a highly potent and selective COX-2 inhibitor (COX-2 IC(50) = 0.077 μM; selectivity index > 1298). It was more selective than the reference drug celecoxib (COX-2 IC(50) = 0.060 μM; selectivity index = 405). A molecular modeling study where 4 was docked in the binding site of COX-2 indicated that the p-MeSO(2) COX-2 pharmacophore group on the C-5 phenyl ring is oriented in the vicinity of the COX-2 secondary pocket. The results of this study showed that the type of substituent on the N-3 hydantoin ring substituent is important for COX-2 inhibitory activity.     

Computer simulation of the in vitro and in vivo anti-inflammatory activities of dihydropyrimidines acid derivatives through the inhibition of cyclooxygenase-2

Simulation of virtually designed 20 compounds as COX-2 inhibitors using molecular modelling of protein–ligand interactions to predict drug structure–activity relationship was performed in this study. A synthetic route with a rational chemical approach to (E)-2-oxo-(thio)-4-substituted phenyl-6-styryl-1,2,3,4-tetrahydro-pyrimidine-5-caboxylic acid was designed and demonstrated. A comparative analysis of antimetabolite drug and corresponding metabolites (virtually designed compounds) provided a better understanding of rational drug design. COX-1(pdb entry: 1eqg) and COX-2(pdb entry: 6cox) enzymes docked with novel ligands were evaluated for binding energies. Lead optimization was performed by computational simulation: methoxy-substituted analogues displayed the highest negative ligand–protein-binding energies. These results prompted us to evaluate in vivo anti-inflammatory activity by carrageenan-induced paw oedema test in rats at a dose of 100 mg/kg. Ibuprofen was administered as standard drug. Lead compounds having significant activity were tested for in vitro cyclooxygenase isoenzyme inhibition assay and found to be more selective towards COX-2 as indicated by COX-2 selective index. The objective of our research is to accept the challenge of discovery of new drug. To ensure the desired target specificity and potency, bioavailability and lack of toxicity, our approach stems out lead generation from virtual screening to their synthesis and ends up with biological assays.