青蒿琥酯纳米粒的制备及其体外细胞抑制试验

目的:制备青蒿琥酯纳米粒,并对其性质及体外细胞抑制作用进行研究。方法:以聚乳酸-羟基乙酸共聚物(PLGA)为载体,采用自乳化方法制备青蒿琥酯纳米粒。扫描电镜观察纳米粒的形态,激光粒度仪测定纳米粒的粒径及其分布;考察纳米粒的载药量、包封率、体外释放情况;MTT法考察纳米粒对人白血病细胞株K562在不同时间(24、48、72h)的体外细胞抑制率,并与青蒿琥酯(原料药)比较。结果:所制青蒿琥酯纳米粒为圆球形,表面光滑,平均粒径为(144±3.0)nm,Zeta电位是-31.5mV,平均载药量和包封率分别为14%、84%;体外释放试验前期有明显突释现象,前24h累积释放度为46%,其后释放均匀,120h累积释放度达65%,具有缓释作用;其在72h时对细胞抑制率高于青蒿琥酯组(76.4%vs.59.1%),有较强抑制作用(P<0.05)。结论:所制青蒿琥酯纳米粒在体外具有较好的缓释性,对K562细胞有较强的抑制作用。     

瑞舒伐他汀钙肠溶缓释微球的制备及影响因素考察

目的采用O/O型乳化溶剂挥发法制备瑞舒伐他汀钙肠溶缓释微球,评价各因素对微球性质的影响。方法以微球的粒径、收率、包封率和释放度作为微球的质量评价指标,研究Eudragit类型、乙基纤维素黏度、两种囊材的质量比、搅拌速度、理论载药量和乳化剂用量对微球性质的影响。结果 Eudragit L100-55制得的微球在酸中突释严重,Eudragit L100能很好地抑制药物在酸中的释放;乙基纤维素(20 cp)制得的微球能在pH值6.8的磷酸盐缓冲液中持续释药10 h;Eudragit L100和乙基纤维素(20 cp)的质量比为70∶30时能得到理想的释放曲线;搅拌速度为600 r.min-1、理论载药量为10%和乳化剂Span 80的质量占液体石蜡质量的2%时能得到较好的微球。结论联合应用pH敏感型材料Eudragit L100和缓释材料乙基纤维素,应用乳化溶剂挥发法可以制备瑞舒伐他汀钙肠溶缓释微球。     

不同载体对缬沙坦纳米骨架载药系统溶出行为和生物利用度影响的研究

目的 通过调节纳米骨架载药系统（NDDS）中载体类型和比例实现对缬沙坦体外溶出和体内生物利用度的调控。方法 以缬沙坦作为模型药物,分别选取酸性敏感材料Eudragit E100（E100）、碱性敏感材料Eudragit L100-55（L100-55）作为载体材料,介孔二氧化硅Sylysia 350（S350）、Aerosil 200（A200）作为纳米骨架,通过调节载体和骨架材料的类型和比例筛选出具有pH 1.2、6.8敏感释放行为的纳米骨架载体处方,考察缬沙坦在pH 1.2、6.8环境中释放和在大鼠体内的药动学行为特征。结果 筛选的pH 1.2敏感释放缬沙坦NDDS处方缬沙坦、S350、E100比例为1∶3∶1,pH 6.8敏感释放缬沙坦NDDS处方为缬沙坦、A200、L100-55比例为1∶1∶3。pH 6.8敏感释放处方可调控缬沙坦在肠道pH 6.8条件下特异性溶出;pH 1.2敏感释放处方在保持缬沙坦在pH 6.8高溶出特性的同时可特异性地提高胃部酸性条件下的药物释放。pH 1.2、6.8敏感释放缬沙坦NDDS均一定程度上改善了缬沙坦的生物利用度,其中pH 6.8敏感释放缬沙坦NDDS提高生物利用度的幅度更高,血药浓度变化比较平缓。结论 NDDS可以调控缬沙坦的体外溶出和生物利用度,有望应用于pH值敏感性难溶药物的递送。     

高效液相-柱后衍生化法测定青蒿琥酯含量

目的建立测定青蒿琥酯的含量测定方法。方法采用反相高效液相色谱-柱后衍生化法,流动相为乙腈-醋酸盐缓冲液(pH4.0)(60∶40),流速0.8ml/min;衍生试剂为1mol/L氢氧化钾的90%乙醇溶液,流速0.5ml/min;反应温度70℃,柱温30℃,检测波长289nm。结果青蒿琥酯在2～100μg/ml范围内线性关系良好,以峰面积对青蒿琥酯浓度进行线性回归,方程为A=1746.8+8525.4C,r=0.99999;日内、日间精密度RSD均<2%;平均回收率均在98.0%～102.0%。结论该法准确、简便、重现性好,可用于青蒿琥酯的质量控制。     

青蒿琥酯贴剂压敏胶处方的研究

目的 考察压敏胶基质处方对青蒿琥酯体外透皮吸收的影响.方法 以聚丙烯酸酯压敏胶为基质设计不同的处方,考察了各种添加剂对青蒿琥酯在聚丙烯酸酯压敏胶基质中结晶的影响;通过改良的Franz透皮扩散池测定青蒿琥酯贴剂中青蒿琥酯透过SD大鼠腹部皮肤的渗透速率,以研究不同压敏胶和不同添加剂对经皮渗透速率的影响.结果 聚丙烯酸树脂Eudragit EPO和聚乙烯吡咯烷酮(PVP-K30)对青蒿琥酯结晶均有较强的抑制作用,能提高青篙琥酯在压敏胶中的载药量.体外透皮试验结果显示,储存6周后,添加Eudragit EPO、PVP-K30的青篙琥酯贴剂中的青篙琥酯的累计透过量比无添加剂贴剂的高.结论 上述研究结果表明,提高青蒿琥酯在基质中的载药量有利于其开发成临床应用的贴剂.     

吲达帕胺肠溶微球的制备及影响因素考察

目的制备吲达帕胺肠溶微球及影响因素考察。方法以羟丙甲纤维素酞酸酯(HPMCP)为肠溶载体材料,采用乳化溶剂扩散法制备吲达帕胺肠溶微球,对影响微球的成型性、收率、载药量、包封率及其释药性能等因素进行了考察。结果微球形态圆整,架桥剂和乳化剂是其成型主要影响因素;载药量14.85%,包封率76.30%,药物在模拟肠液中累计释放度符合要求,载体材料用量控制药物释放速度。结论本方法适宜制备吲达帕胺肠溶微球,工艺简单,体外肠溶释放性良好。     

SM-1小粒径肠溶微丸的制备及体外评价

目的制备SM-1小粒径肠溶微丸,并优化其处方,以达到肠溶和便于小动物给药的目的。方法采用流化床空白丸芯上药法,在丸芯表面依次包覆含药层、羟丙基甲纤维素（HPMC）隔离层和丙烯酸树脂（EudragitL30D-55）肠溶层。以载药量、耐酸性及释放度为指标,对SM-1肠溶微丸的处方进行优化。结果隔离层增重8%,肠溶层增重15%的肠溶微丸粒径〈450μm（40目筛）,圆整度良好,载药量约为20%;在pH为2.0的盐酸溶液中2 h内肠溶衣层薄层完好,药物释放度〈4%;在pH为6.8的PBS溶液中,45 min内释放度均〉70%。结论采用流化床制备SM-1肠溶微丸工艺可行,重现性好,具有良好的肠溶特性,粒径〈380μm,可用于小动物给药。     

喷雾干燥法制备麦冬皂苷肠溶微球的影响因素

以丙烯酸树脂Ⅱ为囊材、微粉硅胶为抗黏剂、蓖麻油为增塑剂、95%乙醇为溶剂,采用喷雾干燥法制得麦冬皂苷肠溶微球.以外观形态、粒径、包封率、释放度等为指标,对进风温度、雾化速度、增塑剂种类、药物与囊材比例、囊材浓度等因素进行考察.结果表明,按优化条件制得的微球表面光滑,平均粒径(20.6±5.2)μm,包封率(94.8±2.7)%,载药量(54.8±2.1) mg/g.在pH 6.8磷酸盐缓冲液中的释放度较好.     

超临界CO2流体技术制备纳豆激酶肠溶微丸的初探

以异丁烯酸-丙烯酸乙酯共聚物Eudragit L100-55为包衣材料,利用超临界CO2流体技术制备纳豆激酶口服肠溶包衣微丸,考察包衣效果,为纳豆激酶口服制剂的研究和开发提供实验依据.采用正交表考察各种因素对试验结果的影响;并按药典规定考察微丸在不同pH释放介质中的药物活性及释放行为.结果显示最适反应条件为:包衣材料和载药微丸质量比为1:2,反应压力和温度分别为20 MPa、35℃,增塑剂柠檬酸三乙酯及助溶剂乙醇均为10%(V/m),抗粘剂滑石粉虽对包衣反应稍有影响.但能显著改善微丸粘连问题.体外实验结果表明所制备的最佳状态肠溶微丸在人工胃酸(pH1.2)环境中2 h仅释放9.7%,并能保持近90%的活性状态;在pH6.8的模拟肠液释放介质中2 h内快速释放达75%.以超临界CO2流体技术制备的纳豆激酶口服肠溶包衣微丸,在人工胃酸环境中几乎不释药,可避免胃酸环境对纳豆激酶活性的破坏;在pH6.8的类肠液环境中药物释放快速而完全,有利于纳豆激酶在肠道中的吸收.     

右旋酮洛芬-β-环糊精微球的处方优化

采用单因素试验法和均匀设计法,优化了右旋酮洛芬-β-环糊精微球的处方和工艺.所得微球包封率和载药量均在回归方程的预测范围内.原药及3批微球在0.1mol/L盐酸及磷酸盐缓冲液(pH6.8)中的溶出参数m、t50、td均有显著性差异(P＜0.01).     

Electrospun diclofenac sodium loaded Eudragit® L 100-55 nanofibers for colon-targeted drug delivery

Eudragit? L 100-55 nanofibers loaded with diclofenac sodium (DS) were successfully prepared using an electrospinning process, and characterized for structural and pharmacodynamic properties. The influence of solvent and drug content on fiber formation and quality was also investigated. Fiber formation was successful using a solvent mixture 5:1 (v/v) ethanol:DMAc. XRD and DSC analysis of fibers confirm electron microscopic evidence that DS is evenly distributed in the nanofibers in an amorphous state. FTIR analysis indicates hydrogen bonding occurs between the drug and the polymer, which accounts for the molecular integration of the two components. In vitro dissolution tests verified that all the drug-loaded Eudragit? L 100-55 nanofibers had pH-dependent drug release profiles, with limited, less than 3%, release at pH 1.0, but a sustained and complete release at pH 6.8. This profile of properties indicates drug-loaded Eudragit? L 100-55 nanofibers have the potential to be developed as oral colon-targeted drug delivery systems.     

In vitro evaluation of coating polymers for enteric coating and human ileal targeting

Recombinant interleukin-10 producing Lactococcus lactis is an alternative therapy for Crohn's disease. For in vivo interleukin-10 production, thymidine, the essential feed component of these recombinant bacteria should be coadministered. Different coating polymers were evaluated in vitro for enteric properties and targeting suitability to the ileum, the major site of inflammation in Crohn's disease. To guarantee ileal delivery, the polymer must dissolve from pH 6.8 and allow complete release within 40 min. Aqoat AS-HF coated pellets (15%) showed poor enteric properties and thymidine was released below pH 6.8. Eudragit FS30D coated pellets (15%) showed good enteric properties, but no thymidine was released within 40 min at pH 6.8. Eudragit S coated pellets (15%) showed good enteric properties after curing at elevated temperature while no thymidine was released within 40 min at pH 6.8. In another approach to pass the proximal small intestine intact, pellets were coated with 30% Eudragit L30D-55. At pH 6.0, they showed a lag-phase of 20 min. No influence of layer thickness was seen above pH 6.5. Alternatively, pellets were coated with a mixture of Eudragit FS30D/L30D-55 but they showed poor enteric properties and thymidine was released below pH 6.8. In conclusion, none of the tested polymers/mixtures ensured enteric properties and ileal targeting.     

Enteric microsphere formulations of papain for oral delivery

Enteric microspheres formulations of papain were prepared by w/o/w emulsion solvent evaporation using hydroxypropyl methylcellulose phthalate (HPMCP), Eudragit L 100 and Eudragit S 100, to avoid gastric inactivation of papain. Smaller internal and external aqueous phase volume provided maximum encapsulation efficiency (74.49-79.76%), least particle size (52.4-60.2 μm) and 21-26% loss of enzyme activity. Release studies in 0.1 N HCl confirmed the gastro-resistance of formulations. The anionic microspheres, zeta potential between -18.21 and -20.06 mV, aggregated in 0.1 N HCl (i.e., gastric pH 1.2), due to protonation of carboxylic groups of enteric polymer and loss of surface charge with subsequent change in zeta potential. The aggregates being <500 μm size would not impede gastric emptying. However, at pH>5.0 (duodenal pH) the microspheres showed de-aggregation due to restoration of surface charge. HPMCP and Eudragit L 100 microspheres facilitated almost complete release of papain within an hour at pH 6.0 and 6.8, respectively while Eudragit S 100 microspheres released 84.56% papain at pH 7.4, following Higuchi kinetics. FTIR spectroscopy revealed entrapment of enzyme; PXRD & DSC indicated amorphous character and SEM showed spherical shape of microspheres. In simulated gastro-intestinal pH condition, HPMCP, Eudragit L 100 and Eudragit S 100 microspheres showed good digestion of paneer and milk protein. Thus, enteric microspheres formulations could serve as potential carrier for oral enzyme delivery. Stability studies indicated the formulations with around 5% overage would ensure 2 years shelf life at room temperature.     

Influence of an enteric polymer on drug release rates of theophylline from pellets coated with Eudragit RS 30D

The purpose of this research study was to investigate the influence of an enteric polymer on the drug release properties of theophylline pellets coated with Eudragit RS 30D. Theophylline pellets were coated with aqueous colloidal dispersions of Eudragit RS 30D containing various amounts of Eudragit L 100-55. The effect of storage conditions on the release of drug from coated pellets was determined as a function of the pH of the dissolution medium. The results from the dissolution study showed significant changes in the dissolution rate of theophylline from pellets coated with Eudragit RS 30D when cured at 40 degrees C for 4 days. No change in the drug release rate was observed when Eudragit L100-55 was present in the Eudragit RS 30D dispersion. Increasing the ratio of Eudragit L100-55 to Eudragit RS 30D resulted in faster drug release rates from the coated pellets. An increase in the pH of the dissolution medium was found to enhance drug release from the pellets coated with Eudragit RS 30D containing Eudragit L 100-55. Theophylline pellets when coated with Eudragit RS 30D containing the enteric polymer Eudragit L100-55 demonstrated no aging effects when stored at elevated temperatures. The overcoating of the pellets with Eudragit RD 100 did not affect the drug release profiles and prevented the particles from agglomerating during curing and storage.     

Statistical optimization of indomethacin pellets coated with pH-dependent methacrylic polymers for possible colonic drug delivery

The objective of this study was to evaluate the effect of two factors (ratio of Eudragit S100 and Eudragit L100 and the coating level) on indomethacin release from pellets in order to optimize coating formulations for colonic delivery. Coating formulations were designed based on the full factorial design. Two independent variables were the ratio of Eudragit S100:Eudragit L100 (1:4, 1:1 and 1:0) and the level of coating (10%, 15% and 20%, w/w), respectively. The evaluated responses were lag time prior to drug release at pH 6.8 (the time required for drug release up to 2%) and percent of drug release at pH 6.8 in 5h. Polymers were coated onto the pellets containing 20% (w/w) indomethacin, using a fluidized bed coating apparatus. Dissolution test was carried out in media with different pH (1.2, 6.5, 6.8 and 7.2). The dissolution data revealed that the level of coating and the ratio of polymers are very important to achieve optimum formulation. Using responses and resulted statistical equations, optimum formulation consisted of Eudragit S100:L100 in 4:1 ratio and the level of coating (20%) was predicted. Practical results showed that the pellets prepared according to above formulation released no indomethacin at pH 1.2 (simulating stomach pH) and pH 6.5 (simulating proximal part of small intestine pH); drug release was slowly at pH 6.8 (simulating lower part of small intestine pH), but it was fast at pH 7.2 (simulating terminal ileum pH). The results of this study revealed that factorial design is a suitable tool for optimization of coating formulations to achieve colon delivery. It was shown that coating formulation consisted of Eudragit S100:Eudragit L100 in 4:1 ratio at 20% coating level has potential for colonic delivery of indomethacin loaded pellets. The optimized formulation produced dissolution profiles that were close to predicted values.     

氟比洛芬肠溶片的制备及其体外释放度研究

目的:制备氟比洛芬肠溶片并考察其体外释放特性。方法:以乙基纤维素(EC)、甲基丙烯酸共聚物(Eudragit S100)、乳糖为辅料,采用直接压片法制备制剂;考察处方中不同辅料用量对药物释放的影响及其在0.1mol·L-1盐酸溶液(HCl)和pH6.8磷酸盐缓冲液(PBS)中的体外释放特性。结果:以EC0.250g、Eudragit S1000.750g、乳糖3.750g时组成的处方可在HCl中不释放,在PBS中完全释放达94.20%。结论:该制剂处方设计和制备方法可行,其释放行为符合设计要求。     

Effect of anionic polymers on the release of propranolol hydrochloride from matrix tablets.

Anionic polymers, namely Eudragit S, Eudragit L 100-55, and sodium carboxymethylcellulose, were incorporated into hydroxypropylmethylcellulose (HPMC K100M) to modify the drug release from HPMC matrices. The effects of changing the ratio of HPMC to anionic polymers were examined in water and in media with different pH. The dissolution profiles were compared according to release rates. The interaction between propranolol hydrochloride and anionic polymers was confirmed using the UV difference spectra method. The drug release was controlled with the type of anionic polymer and the interaction between propranolol hydrochloride and anionic polymers. The HPMC-anionic polymer ratio also influenced the drug release. The matrix containing HPMC-Eudragit L 100-55 (1:1 ratio) produced pH-independent extended-release tablets in water, 0.1 N HCl, and pH 6.8 phosphate buffer.     

Use of enteric polymers for production of microspheres by extrusion-spheronization

To simplify the manufacture of enteric dosage forms, incorporation of enteric polymers into the matrix of phenylbutazone microspheres produced by extrusion-spheronization was compared to the coating of cores. The effect of different polymers, cellulose acetate phthalate (CAP), hydroxypropylmethyl cellulose phthalate (HPMCP) and Eudragit L100-55 and the amount of granulating liquid were evaluated for the effect of selected physical properties and drug release behavior. Using the enteric polymers in the microsphere cores showed a similar pattern of release to the coated spheres with no notable difference in drug release behavior being observed between the dosage forms. The microspheres with Eudragit L100-55 in the matrix were less friable and disintegration times were much closer to the coated microspheres than formulations including the other polymers. Variation of the amount of Eudragit L100-55 in the cores allowed optimization of disintegration and drug release profiles.