Response Surface Methodology for the Optimization of Celecoxib Self-microemulsifying Drug delivery System

The aim of the present study was to prepare, evaluate and optimize, self micro emulsifying drug delivery system of celecoxib. A 3 factor, 3 level factorial design was used for the optimization procedure with different amounts of Labrafil 2609 WL, Labrasol, and Cremophor EL as the independent variables. The response variable was selected on particle size (nm) of the droplets after dilution in 0.1N HCl. Particle size of the self micro-emulsifying drug delivery system depends on the quantity of above three independent variables. Three different levels of each independent variable were selected for the optimization. Mathematical equation and response surface plots were used to relate the dependent and independent variables. The regression equation generated for the particle size after dilution was, Particle size (Y)= +27.83+76.07×A-23.62×B-43.83×C+52.72×A(2)+9.82×B(2)+27.20×C(2)-14.52×A×B-32.38×A×C+12.1×B×C, where, A=Labrafil 2609 WL, B= Labrasol, C= Cremophor EL, Y= particle size. The optimized model predicted a particle size of 28.33 nm with 0.16ml of labrafil 2609 WL, 0.17ml Labrasol and 0.22ml of Cremophor EL. The observed response were in close agreement with the predicted values of the optimized formulation. This demonstrates the reliability of the optimization procedure in predicting particle size of self microemulsifying delivery system for celecoxib.     

Celecoxib decreases expression of the adhesion molecules ICAM-1 and VCAM-1 in a colon cancer cell line (HT29)

BACKGROUND AND PURPOSE: We investigated the ability of celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, to modulate expression of ICAM-1 and VCAM-1 in the colon cancer cell line HT29. EXPERIMENTAL APPROACH: We analysed the effect of celecoxib on ICAM-1 and VCAM-1 protein and mRNA expression in HT29 cells. Experiments were performed in the presence of mitogen-activated protein kinases (MAPK) inhibitors to evaluate the involvement of these kinases in this phenomenon. We evaluated adhesion of HT29 cells to FCS-coated plastic wells in the presence of celecoxib or MAPK inhibitors. Furthermore, we studied the effect of celecoxib on apoptosis. KEY RESULTS: Celecoxib down-regulated ICAM-1 and VCAM-1 expression in HT29 cells in a time- and dose-dependent way. Celecoxib reduced activation of p38 and p55 c-Jun terminal NH(2) kinase (JNK) MAPKs, but did not affect p46 JNK or p42/44 MAPK phosphorylation. Pretreatment with SB202190 or SP600125, specific inhibitors of p38 and JNK MAPKs, respectively, reduced ICAM-1 and VCAM-1 expression in HT29 cells dose-dependently. Adhesion of HT29 cells to FCS-coated plastic wells was inhibited dose-dependently by celecoxib, and also by SB202190 and SP600125. Celecoxib showed a pro-apoptotic effect, inducing Bax and BID but down-regulating Bcl-2. CONCLUSIONS AND IMPLICATIONS: Our findings show that celecoxib caused down-regulation of ICAM-1 and VCAM-1, affecting the adhesive properties of HT29 cells in a COX-2 independent way, inhibiting p38 and p55 MAPKs and activating a pro-apoptotic pathway.     

Celecoxib modulates adhesion of HT29 colon cancer cells to vascular endothelial cells by inhibiting ICAM-1 and VCAM-1 expression

BACKGROUND AND PURPOSE: Cyclooxygenase-2 (COX-2) is highly expressed during inflammation and can promote the progression of colorectal cancer. Interactions between cancer cells and vascular endothelial cells are key events in this process. Recently, the selective COX-2 inhibitor, celecoxib, was shown to inhibit expression of the adhesion molecules, ICAM-1 and VCAM-1, in the human colon cancer cell line HT29 and to inhibit adhesion of HT29 cells to FCS-coated plastic wells. Here, we evaluated the effects of celecoxib on adhesion of HT29 cells to human umbilical vein endothelial cells (HUVEC), mediated by ICAM-1 and VCAM-1, to assess further the potential protective effects of celecoxib on cancer development. EXPERIMENTAL APPROACH: Celecoxib was incubated for 4 h with HT29 cells and HUVEC and adhesion was quantified by a computerized micro-imaging system. Expression analysis of ICAM-1 and VCAM-1 cell adhesion molecules was performed by western blot. KEY RESULTS: Celecoxib (1 nM-10 microM) inhibited, with the same potency, adhesion of HT29 cells to resting HUVEC or to HUVEC stimulated by tumour necrosis factor-alpha (TNF-alpha), mimicking inflammatory conditions. Analysis of ICAM-1 and VCAM-1 expression showed that celecoxib inhibited expression of both molecules in TNF-alpha-stimulated HUVEC, but not in resting HUVEC; inhibition was concentration-dependent and maximal (about 50%) at 10 microM celecoxib. CONCLUSIONS AND IMPLICATIONS: In conclusion, our data show that celecoxib inhibits HT29 cell adhesion to HUVEC and expression of ICAM-1 and VCAM-1, in stimulated endothelial cells. These effects may contribute to the chemopreventive activity of celecoxib in the development of colorectal cancer.     

塞来昔布对大肠癌细胞株HT-29增殖和凋亡的影响

目的：体外观察塞来昔布对大肠癌细胞株HT-29细胞增殖和凋亡的影响,并探讨其可能的作用机制。方法 采用噻唑蓝（MTT）比色法,流式细胞仪（FCM）、吖啶橙/溴化乙啶染色结合荧光显微镜、Western印迹法等技术,研究塞来昔布对HT-29细胞增殖抑制的影响。结果：体外塞来昔布抑制HT-29细胞生长,呈浓度和时间依赖性。DNA直方图示典型的亚二倍体“凋亡峰”,凋亡率在（7.31±2.37）%～（48.30±2.86）%;塞来昔布使G0/G1期细胞比例升高,S期和G2/M期比例下降,呈一定剂量效应关系。典型的凋亡形态学改变：细胞体积缩小、细胞核固缩、凋亡小体形成等。凋亡比例呈剂量和时间依赖。塞来昔布下调细胞周期素依赖蛋白激酶CDK2,CDK4蛋白表达、上调细胞周期素依赖蛋白激酶抑制因子P21WAF1/CIP1蛋白表达。结论：塞来昔布抑制HT-29细胞增殖、诱导凋亡可能与阻止细胞周期进展有关。     

微创全髋关节置换后辅助镇痛下的早期康复训练

背景：施行微创全髋关节置换后患者获得更好的关节功能不仅仅取决于手术,而与置换前关节的活动度、置换后康复锻炼等因素密切相关。 目的：观察辅助镇痛在微创全髋关节置换后早期康复锻炼中的意义。 方法：选择施行微创全髋关节置换的患者42例,随机分为2组,镇痛组在置换后口服塞来昔布下进行早期功能锻炼,对照组不予以止痛药处理。观察镇痛组与对照组目测类比疼痛评分,髋关节功能Harris评分和对手术的整体满意度的差异。 结果与结论：镇痛组置换后7 d内的目测类比疼痛评分明显优于对照组(P < 0.05);镇痛组在置换后6个月内的Harris髋关节功能评分和对手术的整体满意度均明显优于对照组(P < 0.05)。结果表明辅助镇痛能有效减少置换后患者运动时的疼痛,有效地保证了置换后康复计划的顺利进行,短期内提高了髋关节功能。     

塞来昔布对糖尿病大鼠视网膜缝隙连接蛋白Cx43的作用

目的：观察COX-2(cyclooxygenase,COX-2)抑制剂(塞来昔布)对糖尿病大鼠视网膜缝隙连接蛋白Cx43(connexin43, Cx43)表达的影响。

方法：选取SD(Sprague-Dawley)大鼠45只,随机分为3组：对照组、糖尿病组、用药组,每组各15只,采用STZ腹腔注射造模的方式进行造模,快速血糖仪监测各组大鼠空腹血糖,正常对照组、糖尿病模型组、用药组分别用生理盐水、生理盐水、塞来昔布溶液进行灌胃,3mo后采用过量麻醉法处死大鼠,制备视网膜标本,采用免疫组化法观察Cx43蛋白,实时定量PCR技术检测大鼠视网膜Cx43 mRNA的相对表达量,采用SPSS13.0统计软件进行统计分析,对各组检测结果进行比较。

结果：免疫组织化学染色缝隙连接蛋白Cx43在视网膜大鼠的神经节细胞层、神经纤维层、内丛状层、色素上皮层、内皮细胞层可见表达不同程度点状、片状表达,计算机图像灰度分析发现塞来昔布对糖尿病大鼠视网膜Cx43表达有促进作用,正常对照组、糖尿病组、用药组灰度值分别是0.233±0.025、0.124±0.014、0.197±0.021,两两比较差异均有统计学意义(P<0.05); 实时定量PCR检测发现塞来昔布促进糖尿病大鼠Cx43 mRNA表达量增加,正常对照组、糖尿病组、用药组相对表达量分别是0.635±0.084、0.110±0.061、0.367±0.074,两两比较差异有统计学意义(P<0.05)。

结论：缝隙连接蛋白Cx43在糖尿病大鼠视网膜中表达减少,塞来昔布可以减缓糖尿病大鼠视网膜缝隙连接蛋白Cx43表达的减少。     

塞来昔布对Lewis肺癌的抑制作用

目的:观察选择性COX-2抑制剂塞来昔布对Lewis肺癌细胞增殖和Lewis肺癌移植瘤生长的抑制作用,探讨其作用机制.方法:应用不同浓度塞来昔布与Lewis肺癌细胞共培养,以MTT比色法检测细胞增殖,ELISA法检测细胞上清液VEGF浓度,流式细胞术检测细胞凋亡情况.20只C57BL/6小鼠进行Lewis肺癌移植瘤实验,随机分为加药组(每天给以含塞来昔布1 mg/g的食物)和对照组(普通食物),电镜观察药物作用24 h后Lewis肺癌移植瘤细胞的超微结构改变;免疫组化检测移植瘤VEGF和COX-2的表达.结果:塞来昔布对Lewis肺癌细胞增殖有抑制作用,效应呈剂量(120、50、12.5、3.1、0 μmol/L)和时间(24、48、72 h)依赖性.50 μmol/L塞来昔布组细胞凋亡率为(14.93±0.79)%,明显高于对照组的(4.73±0.83)%(P<0.001).药物组移植瘤质量为(1.37±1.04) g,明显低于对照组的(3.49±1.75) g (P<0.01),抑瘤率为60.1%.电镜观察Lewis肺癌组织,药物组出现较多有凋亡特征的细胞.免疫组化结果显示塞来昔布对肿瘤组织的VEGF表达有明显抑制作用.结论:塞来昔布可在体内及体外抑制Lewis肺癌细胞增殖,诱导肿瘤细胞凋亡和抑制肿瘤血管生成是其可能的作用机制.     

Characteristics and molecular basis of celecoxib modulation on K(v)7 potassium channels

BACKGROUND AND PURPOSE

Celecoxib is a selective cyclooxygenase-2 (COX-2) inhibitor used for the treatment of pain and inflammation. Emerging and accumulating evidence suggests that celecoxib can affect cellular targets other than COX, such as ion channels. In this study, we characterized the effects of celecoxib on K_v7 K⁺ channels and compared its effects with the well-established K_v7 channel opener retigabine.

EXPERIMENTAL APPROACH

A perforated whole-cell patch technique was used to record K_v7currents expressed in HEK 293 cells and M-type currents from rat superior cervical ganglion neurons.

KEY RESULTS

Celecoxib enhanced K_v7.2–7.4, K_v7.2/7.3 and K_v7.3/7.5 currents but inhibited K_v7.1 and K_v7.1/KCNE1 currents and these effects were concentration dependent. The IC₅₀ value for inhibition of K_v7.1 channels was approximately 4 µM and the EC₅₀ values for activation of K_v7.2–7.4, K_v7.2/K_v7.3 and K_v7.3/K_v7.5 channels were approximately 2–5 µM. The effects of celecoxib were manifested by increasing current amplitudes, shifting the voltage-dependent activation curve in a more negative direction and slowing the deactivation of K_v7 currents. 2,5-Dimethyl-celecoxib, a celecoxib analogue devoid of COX inhibition activity, has similar but greater effects on K_v7currents. K_v7.2(A235T) and K_v7.2(W236L) mutant channels, which have greatly attenuated responses to retigabine, showed a reversed response to celecoxib, from activation to inhibition.

CONCLUSIONS AND IMPLICATIONS

These results suggest that K_v7 channels are targets of celecoxib action and provide new mechanistic evidence for understanding the effects of celecoxib. They also provide a new approach to developing K_v7 modulators and for studying the structure–function relationship of K_v7 channels.