白术黄连微丸结肠靶向胶囊的制备及体外释放研究

目的 将中药"白术黄连方"制备成以胃溶微丸和肠溶微丸为基础的结肠靶向胶囊,优化其处方组成和制备工艺,考察其体外释放特性.方法 采用单因素实验和正交实验法优化微丸的处方组成和工艺参数.用挤出-滚圆技术制备素丸,流化床底喷方式进行包衣,考察隔离衣增重、肠溶衣中聚合物比例、增塑剂用量和包衣增重对肠溶微丸释放行为的影响,并对其...     

肠康宁结肠靶向胶囊体外释放度的评价

目的 对pH依赖型肠康宁结肠靶向胶囊体外释放性能进行评价,探讨制备中药结肠靶向制剂的可行性.方法 以木犀草素为评价指标,采用体外释放度测定法对该制剂的体外释放性能进行评价.结果 体外释放度试验结果表明,木犀草素在人工胃液2h后未见释放,在人工小肠液4h后未见释放,在人工结肠液1h后有一定的释放,2h后释放较高.结论 该制剂能在结肠定位释药.     

Orally delivered polycurcumin responsive to bacterial reduction for targeted therapy of inflammatory bowel disease

Inflammatory bowel disease (IBD) such as Crohn’s disease and ulcerative colitis is a chronic autoimmune disease affecting nearly five million people worldwide. Among all drug delivery system, oral administration is the most preferable route for colon-specific targeting and the treatment of IBD. Herein, an amphiphilic curcumin polymer (PCur) composed of hydrophilic poly(ethylene glycol) (PEG) and hydrophobic curcumin (Cur) linked by disulfide bond was synthesized and characterized. The sufficient solubility, nano-scaled size and close to the neutral surface potential of PCur lead to preferential accumulation of the active drug in the inflamed regions of the gut. Moreover, PCur showed limited drug release and enhanced robustness under the physiological pH of the gastrointestinal tract (GIT), and a significantly elevated release was observed when responding to a bacterial reduction in the colon. Furthermore, cellular studies confirmed PCur had low cytotoxicity and increased transmembrane permeability, resulting in improved oral bioavailability evidenced by in vivo pharmacokinetics of rats. Finally, with DSS-induced murine model of IBD, we demonstrated that orally administered PCur ameliorated the inflammatory progression in the colon and could protect mice from IBD. In conclusion, it is illustrated that the developed PCur conjugate could potentially be employed as a colon-specific candidate for IBD treatment.     

Proof-of-concept study on the suitability of 13C-urea as a marker substance for assessment of in vivo behaviour of oral colon-targeted dosage forms

Background and purpose:

¹³C-urea may be a suitable marker to assess the in vivo fate of colon-targeted dosage forms given by mouth. We postulated that release in the colon (urease-rich segment) of ¹³C-urea from colon-targeted capsules would lead to fermentation of ¹³C-urea by bacterial ureases into ¹³CO₂. Subsequent absorption into the blood and circulation would lead to detectable ¹³C (as ¹³CO₂) in breath. If, however, release of ¹³C-urea occurred in the small intestine (urease-poor segment), we expected detectable ¹³C (as ¹³C-urea) in blood but no breath ¹³C (as ¹³CO₂). The differential kinetics of ¹³C-urea could thus potentially describe both release kinetics and indicate the gastrointestinal segment of release.

Experimental approach:

The in vivo study consisted of three experiments, during which the same group of four volunteers participated.

Key results:

The kinetic model was internally valid. The appearance of ¹³C-in breath CO₂ (F_fermented) and the appearance of ¹³C in blood as ¹³C-urea (F_{not fermented}) show a high inverse correlation (Pearson''s r=−0.981, P= 0.06). The total recovery of ¹³C (F_fermented+F_{not fermented}) averaged 99%, indicating complete recovery of the administered ¹³C via breath and blood. ¹³CO₂ exhalation was observed in all subjects. This indicates that ¹³C-urea was available in urease-rich segments, such as the caecum or colon.

Conclusions and implications:

In this proof-of-concept study, ¹³C-urea was able to provide information on both the release kinetics of a colon-targeted oral dosage form and the gastrointestinal segment where it was released.     

布地奈德结肠定位片的大鼠结肠靶向性评价

 目的比较大鼠口服不同布地奈德制剂后药物在胃肠道各段中的组织浓度,评价布地奈德结肠定位片的结肠定位效果。方法大鼠分别饲服布地奈德定位片、布地奈德普通片和布地奈德混悬液后,定时取样,采用HPLC测定药物在大鼠胃、小肠、大肠等各组织中的浓度分布。结果大鼠口服定位片后,大肠组织中的药物浓度于6 h时达到峰值,c_max=(7.17±2.32)μg·g^-1,明显高于混悬液组(1.37±0.82)μg·g^-1和普通片组(0.47±0.18)μg·g^-1;考察同一时间不同口服制剂对布地奈德在大鼠胃肠道组织分布的影响,发现口服定位片后,除大肠组织外,在胃部和小肠部等其他组织均无药物分布。结论布地奈德结肠定位片具有显著的结肠靶向性。     

4-氨基水杨酸钠结肠靶向胶囊定位研究

目的：考察4-氨基水杨酸钠结肠定位胶囊体内靶向性。方法：利用X-射线跟踪技术验证4-氨基水杨酸钠口服结肠定位胶囊在人体内的靶向性。结果：4-氨基水杨酸钠结肠定位胶囊在结肠黏附性、靶向性较好。结论：该实验为4-氨基水杨酸钠结肠定位胶囊的研究提供了一定实验基础。     

溃结康片的研制

 目的研制用于结肠靶向给药的溃结康片。方法以果胶为载体,采用单因素考察和均匀设计优选溃结康片芯的最佳处方。用Eudragit R-Eudragit S(1∶1)混合膜材包衣,考察包衣增重对骨架片芯释药的影响。以芍药苷和黄芩苷体外释放度为指标,评价释药性能。结果溃结康片的骨架材料组成为:果胶30%,HPMC K4M14%,硬脂酸16%。衣膜增重12%。该包衣骨架片经历0.1 mol·L^-1HCl 2 h,PBS6.8 2 h基本不释药,变换介质为PBS7.5中释放1 h后,芍药苷和黄芩苷的累积释放度均小于20%,再置PBS 6.0果胶酶溶液中4 h,9 h累积释药80%以上。而转入不含酶的PBS 6.0者,9 h两成分的累积释放度均小于50%。结论研制的溃结康片具有结肠酶解释药特点。     

大黄泻下的大肠靶向给药之我见

目的 :从药剂学的角度出发阐明大黄作为泻下剂应大肠靶向给药的观点。方法 :根据近 6 0年国内外药理学、药剂学及临床实验研究 ,论述了结合蒽醌、特别是游离蒽醌对大肠蠕动和转运时间的影响和它们的吸收特点 ,以及大黄提取、浓缩、干燥过程中成分的损失情况。结果及结论 :大黄提取物中的游离蒽醌应视为有效泻下成分 ;不仅应注意大黄提取、浓缩、干燥过程中游离蒽醌的损失 ,更应注意游离蒽醌在上消化道转运过程中的损失 ;大肠靶向给药可阻止游离蒽醌在上消化道的吸收 ,将有利于提高疗效和降低用量。     

口服结肠靶向制剂中辅料的应用

目的:介绍辅料在口服结肠靶向制剂中的应用,为更深入的研究提供参考。方法:通过查阅国内外大量相关文献,对常用于口服结肠靶向制剂的几种辅料及其相应的释药系统进行分析概述。结果:辅料是药物制剂的基础材料和重要组成部分,在口服结肠靶向制剂的发展和生产中起关键作用。结论:辅料的选择对制剂的结肠定位起至关重要的作用。     

Development and in vitro/in vivo evaluation of Zn-pectinate microparticles reinforced with chitosan for the colonic delivery of progesterone

The colon is a promising target for drug delivery owing to its long transit time of up to 78?h, which is likely to increase the time available for drug absorption. Progesterone has a short elimination half-life and undergoes extensive first-pass metabolism, which results in very low oral bioavailability (～25%). To overcome these shortcomings, we developed an oral multiparticulate system for the colonic delivery of progesterone. Zn-pectinate/chitosan microparticles were prepared by ionotropic gelation and characterized for their size, shape, weight, drug entrapment efficiency, mucoadhesion and swelling behavior. The effect of cross-linking pH, cross-linking time and chitosan concentration on progesterone release were also studied. Spherical microparticles having a diameter of 580–720?µm were obtained. Drug entrapment efficiency of ～75–100% was obtained depending on the microparticle composition. Microparticle mucoadhesive properties were dependent on the pectin concentration, as well as the cross-linking pH. Progesterone release in simulated gastric fluids was minimal (3–9%), followed by burst release at pH 6.8 and a sustained phase at pH 7.4. The in vivo study revealed that the microparticles significantly increased progesterone residence time in the plasma and increased its relative bioavailability to ～168%, compared to the drug alone. This study confirms the potential of Zn-pectinate/chitosan microparticles as a colon-specific drug delivery system able to enhance the oral bioavailability of progesterone or similar drugs.