硝苯地平膜控型控释微丸的制备及体外评价

目的研究硝苯地平(NF)膜控型24 h控释微丸的处方与工艺,并考察其体外释放特性。方法采用液相层积、丸芯上药法制备载药速释微丸,以Eudragit RL100、RS100为包衣材料,流化床悬浮包衣法制备膜控型控释微丸,并对影响微丸释放的处方因素进行了考察。通过与市售渗透泵片拜新同的体外释放度的对比研究,探讨硝苯地平膜控型控释微丸的体外释药特征。结果调整Eudragit RL100、RS100的比例、衣层厚度、致孔剂的用量,可以改变药物的释放速率。当Eudragit RL100、RS100的比例为3∶7,包衣增重为6%时,制备的控释微丸体外释药与市售渗透泵片相似(f2=62.8),具有良好的零级释放特性。结论以丸芯上药法,Eudragit RL100、RS100为控释材料制备的NF膜控型控释微丸,具有良好的零级释放特性,结果可为硝苯地平多单元控释制剂的研究开发提供参考。     

混合水分散体肠溶迟释薄膜性能研究

目的 采用肠溶型水分散体Eudragit?L30D-55和控释型水分散体Kollicoat?SR30D混合制备一种全新的对周围环境pH值具有响应的,同时具有迟释性能的聚合物薄膜。方法 采用铸膜法制备L30D-55∶SR30D混合水分散体游离膜,采用差示扫描量热法(DSC)测定薄膜玻璃化转变温度(glass transition temperature,Tg),万能材料试验机测试薄膜拉伸性能,杯法考察薄膜透湿性能。考察聚合物比例、附加剂种类和用量对薄膜性能的影响,并以制备泮托拉唑钠(PAZ-Na)肠溶迟释微丸考察包衣膜特性。结果 随着SR30D的增加,薄膜的Tg逐渐降低,强度和刚性变弱,韧性变强,透湿性能先不变后增加。随着增塑剂增加,薄膜刚性减弱,渗透性能增强。不溶性成分的加入可不同程度降低薄膜的渗透性。制备的肠溶迟释微丸在0.1 mol·L^-1盐酸中2 h药物损失量<5%,在pH 6.8缓冲液中可延迟10~20 min开始释放,并至90 min释放完全。结论 L30D-55∶SR30D混合水分散体制备的游离膜和包衣膜具有良好的理化性能,可用于肠溶调释制剂的研究和开发。     

硝酸异山梨酯缓释微丸处方及工艺优化

目的制备硝酸异山梨酯缓释微丸,优化处方及制备过程。方法采用粉末层积法和流化床喷雾法制备膜控缓释微丸,用单因素考察实验优化处方及工艺,采用HPLC法测定缓释微丸的累积释放度。结果确定以Eudragit RS30D和Eudragit RL30D混合分散体为包衣材料,Eudragit RS30D与Eudragit RL30D的比例是4∶1,包衣增重为5%,热处理温度、时间为40℃、24小时,抗静电剂、增塑剂分别占包衣聚合物量的0.5%、20%。在体外释放度实验中,微丸累积释放硝酸异山梨酯百分率,0.5小时为10.71%,2小时为45.80%,8小时90.79%,24小时为99.14%。结论体外释放度实验中,Eudragit RS30D与Eudragit RL30D的比例对微丸累积释放度的影响较大,随着包衣量增加,释放度略有降低。本制剂为膜控制剂。     

5-氨基水杨酸结肠定位给药pH与时间同时控释小丸的制备与体外释放

目的:用水分散体包衣技术制备5-氨基水杨酸 (5-ASA) 结肠定位小丸给药系统.方法:以Eudragit(R) RL30D作为时间控释包衣内层,Eudragit(R) S水分散体作为pH控释外层,三乙酸甘油酯为增塑剂,使用流化床包衣设备,制备pH值与时间同时控释的小丸,用释放度测定法研究小丸在不同pH介质中的释放度.结果:小丸在模拟胃酸情况下不释药,在变换pH 7.5条件下9h内释药完全.Eudragit(R) S层保证小丸安全通过胃;而药物释放速度是由丸心、Eudragit(R) RL30D时间控释层来控制.利用小肠相对恒定的转运时间(3～4h)和小肠末端高pH(7～8),及不同Eudragit(R)聚合物的pH性质制备了较可靠的多剂量结肠给药系统.结论:通过调整内外层包衣厚度可制备5-ASA结肠定位释放小丸.     

Eudragit L30D-55和NE30D在软胶囊肠溶包衣中的应用

以Eudragit L30D-55为肠溶衣材料,通过加入Eudragit NE30D调整肠溶衣膜的延展性,以聚乙二醇6000为增塑剂调节最低成膜温度,通过正交试验优化了软胶囊包衣液的处方.3批肠溶软胶囊于(25±2)℃、RH(60±5)%环境放置6个月,均符合中国药典2005年版肠溶制剂的相关标准.     

酒石酸美托洛尔缓释微丸的制备及处方因素考察

目的：选用Eudragit RS 30 D与Eudragil RL30D两种包衣材料，制备日服2次的酒石酸美托洛尔缓释徽丸，并对其处方因素进行考察。方法：采用Glatt流化床底喷溶液上药法制备载药微丸，考察缓释聚合物Eudragit RS 30D与Eudragit RL 30D的不同质量配比（2：3，7：3和9：1）、聚合物包衣增重（10％，20％和30％）以及增塑利嗣量（10％，20％和40％）和放置时间对药物释放的影响。结果：当Eudragit RS 30D与Eudragit RL 30D的质量比为9：1，聚合物包衣增重为20％，增塑剂用量为20％时，药物的释放行为符合中国药典对缓释制剂释放度的相关规定。结论：通过调整Eudragit RS 30D与Eudragit RL 30D之间的比例，或提高聚合物包衣增重等手段，能使酒石酸美托洛尔载药徽丸具备较理想的缓释效果。     

不同方法制备的控释膜力学与药物渗透性能研究

分别采用平面铸膜法和喷雾法制备游离的Eudragit RS100控释包衣膜，通过张力仪测定了膜力学性能，并以盐酸氨溴索为模型药物测定了膜的渗透性能，以考察两种方法制备的控释膜性能的重现性，试验结果显示两法制备的膜力学性能差异显著，但重现性均符合要求，喷雾法制备的控释膜盐酸氨溴索的渗透速率重现性差而平面铸膜法制备的膜重现性则较好，此外平面铸膜法制备的膜其盐酸氨溴索的渗透速率仅由膜本身控释能力决定，不受搅拌速率，供给池药物浓度变化等因素影响，即实验因素影响小，较适用于薄膜试验。     

帕利哌酮缓释微丸的处方优化

该研究采用挤出滚圆法制备了帕利哌酮丸芯，再用甲基丙烯酸共聚物(Eudragit)包衣制备缓释微丸，并采用正交设计分别优化了载药丸芯和缓释微丸的处方包衣工艺参数。结果表明，采用Eudragit RS30D与Eudragit RL30D作为包衣材料，且Eudragit RS30D占包衣材料总量65%时得到的优化缓释微丸在不同pH介质中的体外释放行为符合一级动力学方程。     

盐酸伪麻黄碱脉冲小片包衣液处方优化

目的制备盐酸伪麻黄碱脉冲控释小片,并对其体外释药情况进行研究。方法制备盐酸伪麻黄碱含药片芯,采用丙烯酸树脂水分散体(Eudragit(RS 30D)制备盐酸伪麻黄碱脉冲控释小片。通过单因素实验考察药物释放的影响因素,确立处方组成,采用正交设计对包衣液处方进行优化。结果当隔离层增质量分数为2%、控释层增质量分数为5%、CMS-Na用量质量分数为25%,脉冲控释小片的时滞为6 h,体外具有脉冲释药特性。结论成功地制备了盐酸伪麻黄碱脉冲控释小片,体外释药符合脉冲释药的要求。     

平痛新控释微丸的包衣液处方筛选

目的筛选平痛新控释微丸包衣液处方。方法用单因素实验方法考察了包衣液中溶媒系统的组成、膜材的浓度、致孔剂和增塑剂对药物释放的影响。结果膜材浓度增加、水比例增大释药速度加快;加入PVPK30,加快释药,这些与包衣厚度共同决定衣膜的控释能力。结论包衣液处方合理、实用。     

The Effect of Plasticizers on Compatibility,Mechanical Properties,and Adhesion Strength of Drug-Free Eudragit E Films

The use of plasticizers to affect the properties of drug-free, self-adhesive Eudragit E-100 films with higher transparency was tested for possible transdermal drug delivery. Triacetin was found to be an effective first plasticizer for Eudragit E-100 polymer. In order to improve the flexibility and adhesiveness of Eudragit E-100 film plasticized with triacetin, a more flexible and adhesive, secondary plasticizer was added. Plasticizer–polymer compatibility was evaluated by measuring transparency, surface topography, and solubility. Secondary plasticizers with a low molecular weight and a solubility parameter similar to that of Eudragit E-100 polymer and triacetin were compatible. Further, a lower molecular weight or higher concentration of the secondary plasticizers might lead to greater plasticizing action, reduce tensile strength, and increase film elongation, independent of the hydrophilicity of the plasticizer. The adhesive strength of Eudragit E-100 film under a 180° peel test was also affected by the molecular weight and solubility parameter of the secondary plasticizers used. The results indicate that PEG 200, propylene glycol, diethyl phthalate, and oleic acid can serve as a secondary plasticizer to improve the transparency, flexibility, and adhesion of Eudragit E-100 film.     

Transdermal delivery of salbutamol sulphate: Formulation and evaluation

Salbutamol patches were prepared and evaluated. The effect of different Eudragits and various plasticizers on the properties of the patches were studied. Patches were prepared by casting method employing different plasticizers. These patches were evaluated for weight, thickness uniformity, swelling index, tensile strength, elongation percent and moisture absorption capacity. Release was studied. Tensile strength of the patches using Eudragit RS 100 as well as RS100 + L100 and triacetin was the lowest. Formulae containing 10% oleic acid and 5% dimethyl formamide, respectively, showed the highest permeability. These two formulae were studied clinically, the first formula only showed a significant improvement.     

The use of dynamic mechanical analysis (DMA) to evaluate plasticization of acrylic polymer films under simulated gastrointestinal conditions

PurposeGlass transition temperature (T_g) measurements of polymers are conventionally conducted in the dry state with little attention to the environment they are designed to work in. Our aim was to develop the novel use of dynamic mechanical analysis (DMA) to measure the T_g of enteric polymethacrylic acid methylmethacrylate (Eudragit L and S) polymer films formulated with a range of plasticizers in the dry and wet (while immersed in simulated gastric media) states.MethodsPolymer films were fabricated with and without different plasticizers (triacetin, acetyl triethyl citrate, triethyl citrate, polyethylene glycol, propylene glycol, dibutyl phthalate, dibutyl sebacate). T_g was measured by a dynamic oscillating force with simultaneous heating at 1 °C/min. This was conducted on films in the dry state and while immersed in 0.1 M HCl to simulate the pH environment in the stomach.ResultsThe T_g of unplasticized Eudragit L and S films in the dry state was measured to be 150 and 120 °C, respectively. These values were drastically reduced in the wet state to 20 and 71 °C for Eudragit L and S films, respectively. The plasticized films showed similar falls in T_g in the wet state. The fall in T_g of Eudragit L films to below body temperature will have far-reaching implications on polymer functionality and drug release.ConclusionsImmersion DMA provides a robust method for measuring T_g of polymer films in the wet state. This allows better prediction of polymer behaviour in vivo.     

Mechanical Properties of Dry and Wet Cellulosic and Acrylic Films Prepared from Aqueous Colloidal Polymer Dispersions Used in the Coating of Solid Dosage Forms

The mechanical properties of dry and wet polymeric films prepared from various aqueous polymeric dispersions were evaluated by a puncture test. They were studied with respect to type of polymer dispersion [cellulosic: Aquacoat and Surelease; acrylic: Eudragit NE, L, RS, and RL 30 D], plasticizer type (water-soluble or water-insoluble), drying or curing conditions, method of film preparation (pseudolatex- vs solvent casting) and ratio of Eudragit RS/RL 30 D in mixed Eudragit RS/RL films. Dry and wet mechanical strengths of the polymeric films depended primarily on the types of the colloidal polymer dispersion and the plasticizer. Films prepared from ethylcellulose dispersions resulted in very weak and brittle films when compared to the acrylic films. Pseudolatex-cast ethylcellulose films showed lower puncture strength and elongation values when compared to those of the solvent-cast films. Curing of the pseudolatex-cast ethylcellulose films had minimal effects on their mechanical properties. Eudragit L 30D, an enteric polymer dispersion, resulted in brittle films in the dry state, but in very flexible films in the wet state because of the plasticization effect of water. Wet Eudragit RS 30 D polymer films plasticized with water-insoluble plasticizers were significantly more flexible than the corresponding wet films plasticized with water-soluble plasticizers. The water-soluble plasticizers leached from the films during exposure to the aqueous medium, while the water-insoluble plasticizers were almost completely retained within the wet films. The low permeability of a water-soluble drug, chlorpheniramine maleate, and the weak mechanical properties of Aquacoat films could suggest osmotic driven/rupturing effects as the release mechanisms from Aquacoat-coated dosage forms.     

Ocular inserts for controlled delivery of pefloxacin mesylate: preparation and evaluation

Pefloxacin mesylate is a flouroquinolone antibacterial drug effective in the treatment of bacterial conjunctivitis. The objective of the present work was to develop ocular inserts of pefloxacin mesylate and evaluate their potential for sustained ocular delivery. Reservoir-type ocular inserts were prepared by the film casting technique in teflon coated Petri dishes and characterized in vitro by drug release studies using a flow-through apparatus that simulated the eye conditions. Six formulations were developed, which differed in the ratio of polymers Eudragit RS 100 and Eudragit RL 100 used for the preparation of the rate controlling membrane. All formulations carried 0.72 mg pefloxacin mesylate, 2.69 mg polyvinyl pyrrolidone (PVP) K-30, plasticizers, propylene glycol (10% m/m) and dibutyl phthalate (15%, m/m). The optimized formulation was subjected to microbiological studies, in vivo studies, interaction studies, and stability studies to assess the effectiveness of the formulation. Cumulative drug released from the formulation ranged from 90-98% within 48 to 120 hours. On the basis of in vitro drug release studies, the formulation with Eudragit RS 100/Eudragit RL 100 (4:1) was found to be better than the other formulations and it was selected as an optimized formulation. On the basis of in vitro, microbiological, in vivo drug release, interaction and stability studies, it can be concluded that this ocular insert formulation provided the desired drug release in vitro for 5 days and remained stable and intact at ambient conditions.     

Tackiness of acrylic and cellulosic polymer films used in the coating of solid dosage forms.

The objective was to determine the tackiness of acrylic and cellulosic polymer films in order to make predictions on the tackiness (agglomeration) of coated dosage forms during coating and curing. Force-displacement curves of the detachment process of two polymeric films were used as a measure of tackiness. Various polymers (cellulosic (Aquacoat and acrylics (Eudragit RS 30D, L 30D, NE 30D)), plasticizers (triacetin, triethyl citrate, tributyl citrate, acetyltributyl citrate) and anti-tacking agents (talc and glyceryl monostearate) were investigated. The order of tackiness for films prepared from the different aqueous polymer dispersions was in order of Eudragit NE 30D > RS 30D > RL 30D > Aquacoat. The tackiness increased with increasing plasticizer concentration due to the softening of the polymer. A correlation between the minimum film formation temperature and the tackiness was observed, however, no correlation between the tackiness and the lipophilicity of the plasticizer was seen. Talc and glyceryl monostearate (GMS) reduced the tackiness of the films significantly, with GMS being effective at much lower concentrations. Curing of Eudragit RS 30D-coated theophylline beads at temperatures higher than 40 degrees C in an irreversible agglomeration of the beads and damage of the coating upon separation of the beads. This resulted in a faster release than with uncured beads. Blending the beads with talc just prior to the curing step eliminated the agglomeration and therefore film damage, even at a curing temperature of 60 degrees C.     

Dry polymer powder coating and comparison with conventional liquid-based coatings for Eudragit) RS, ethylcellulose and shellac.

Drug-layered pellets were coated with micronized polymer powders (Eudragit) RS, ethylcellulose, and shellac) by a dry powder coating technique as an alternative to organic- and aqueous-based coatings (Eudragit) RS 30D, Aquacoat) ECD) were investigated. High plasticizer concentrations (40%) and a thermal after-treatment (curing) were necessary for the coalescence of the polymer particles and good film formation. Ethylcellulose required a higher curing temperature and time than Eudragit) RS because of its higher glass transition temperature (133 versus 58 degrees C). A smaller polymer particle size also promoted film formation. In general, pellets coated with polymer powders required higher coating levels to obtain similar drug release patterns as pellets coated with organic polymer solutions and aqueous polymer dispersions.     

Combination of time-dependent and pH-dependent polymethacrylates as a single coating formulation for colonic delivery of indomethacin pellets

The objective of this study was to evaluate the combination of pH-dependent and time-dependent polymers as a single coating for design of colon delivery system of indomethacin pellets. Eudragit S100 and Eudragit L100 were used as pH-dependent polymers and Eudragit RS was used as a time-dependent polymer. A statistical full factorial design was used in order to optimize formulations. Factors studied in design were percent of Eudragit RS in combination with Eudragit S and L and coating level. Dissolution studies of pellets in the media with different pH (1.2, 6.5, 6.8 and 7.2) showed that drug release in colon could be controlled by addition of Eudragit RS to the pH-dependent polymers. The lag time prior to drug release was highly affected by coating level. With combination of two factors, i.e. the percent of Eudragit RS and coating level, the optimum formulation was found to be the one containing 20% Eudragit RS, 64% Eudragit S and 16% Eudragit L, and a coating level of 10%. This formulation was reproduced and tested in continuous condition of dissolution, and also separately at pH 7.5. The results of in vitro experiments indicate that the proposed combined time-dependent and pH-dependent polymethacrylate polymer coating may provide a colonic delivery system for indomethacin.     

An evaluation of the plasticizing efficiency of the dialkyl phthalates in ethyl cellulose films using the torsional braid pendulum

The plasticizing efficiency of the dialkyl phthalates when added to ethyl cellulose has been evaluated by measuring the glass transition temperatures of formulations using the torsional braid pendulum—a dynamic mechanical technique originally invented for following the rigidity changes accompanying the curing of polymers. The plasticizing efficiency of the four phthalates used was found to be diethyl > dimethyl > dibutyl > dioctyl. In the case of dioctyl phthalate phase separation was so pronounced that there was little effect on the glass transition temperature of the ethyl cellulose. Measured values for the glass transition temperatures were compared with predicted values using a suitable mixture-rule model. Agreement was limited to the case of diethyl phthalate at plasticizer concentrations below 20% w/w.     

Non-traditional plasticization of polymeric films

The objective of this study was to investigate the influence of methylparaben, ibuprofen, chlorpheniramine maleate and theophylline on the thermal and mechanical properties of polymeric films of Eudragit RS 30 D. The effects of methylparaben and ibuprofen in the film coating on the rate of drug release from Eudragit RS 30 D coated beads were also studied. The physical and mechanical properties of the cast films and coated beads were investigated using thermal analysis, tensile testing, X-ray diffraction analysis and dissolution testing. The results demonstrated that the glass transition temperature of the Eudragit RS 30 D decreased with increasing levels of methylparaben, ibuprofen and chlorpheniramine maleate in the film. Theophylline exerted no influence on the thermal properties of the polymer. The higher levels of the ibuprofen and methylparaben incorporated into the film resulted in a decrease in the tensile strength of the film. The decrease in Young's modulus of Eudragit RS 30 D coated beads was attributed to an increase in the flexibility of the polymeric films when the level of methylparaben or ibuprofen in the polymeric dispersion was increased. The dissolution data demonstrated that the rate of release of the ibuprofen from coated beads was decreased by increasing the amount of ibuprofen and methylparaben in the polymeric film coating.