添加剂对干粉涂料熔体黏度、表面张力和成膜性能的影响。
Influence of additives on melt viscosity, surface tension, and film formation of dry powder coatings.
机构信息
Drug Dynamics Institute, College of Pharmacy, The University of Texas at Austin, Austin, TX 78712, USA.
出版信息
Drug Dev Ind Pharm. 2009 Jun;35(6):646-54. doi: 10.1080/03639040802516483.
BACKGROUND
Limited information on thermally cured dry-powder coatings used for solid dosage forms has been available in the literature.
AIM
The aim of this study was to characterize the film formation process of Eudragit L 100-55 dry-powder coatings and to investigate the influence of film additives on melt viscosity and surface tension.
METHODS
The coating process employed no liquids and the plasticizer was combined with the polymer using hot melt extrusion. Thermoanalytical methods including differential scanning calorimetry and thermogravimetric analysis (TGA) were used to investigate the thermal properties of the dry-coating formulations. The rheological behavior of the coating formulations were characterized with the extrusion torque, and the surface energy parameters were determined from contact angle measurements. The influence of the level of triethyl citrate (TEC) as plasticizer and polyethylene glycol (PEG) 3350 in the polymer film on film formation was investigated using a digital force tester.
RESULTS
TGA confirmed thermal stability of all coating excipients at the investigated curing conditions. Increasing TEC levels and the addition of PEG 3350 as a low melting excipient in the coating reduced the viscosity of the polymer. Plasticization of the polymer with TEC increased the surface free energy, whereas the admixture of 10% PEG 3350 did not affect the surface free energy of Eudragit L 100-55. The spreading coefficient of the polymers over two sample tablet formulations was reduced with increasing surface free energy. During the curing process, puncture strength, and elongation of powder-cast films increased. The effect of curing time on the mechanical properties was dependent on the plasticizer content.
CONCLUSIONS
The incorporation of TEC and PEG 3350 into the Eudragit L 100-55 powder coating formulation improved film formation. Mechanical testing of powder-cast films showed an increase of both elongation and puncture strength over the curing process as criterion for polymer particle fusion, where film formation progressed faster at high plasticizer levels.
背景
关于用于固体制剂的热固化干粉涂料的信息在文献中有限。
目的
本研究的目的是表征 Eudragit L 100-55 干粉涂料的成膜过程，并研究薄膜添加剂对熔体粘度和表面张力的影响。
方法
该涂层工艺不使用任何液体，增塑剂与聚合物一起使用热熔挤出。使用差示扫描量热法和热重分析（TGA）等热分析方法研究了干涂层配方的热性能。通过挤出扭矩来描述涂层配方的流变行为，并通过接触角测量来确定表面能参数。使用数字力测试仪研究了增塑剂三乙基柠檬酸（TEC）的水平和聚合物薄膜中聚乙二醇（PEG）3350 的水平对薄膜形成的影响。
结果
TGA 证实了所有涂层赋形剂在研究固化条件下的热稳定性。增加 TEC 水平和在涂层中添加低熔点赋形剂 PEG 3350 降低了聚合物的粘度。TEC 对聚合物的增塑作用增加了聚合物的表面自由能，而 10%PEG 3350 的混合物对 Eudragit L 100-55 的表面自由能没有影响。聚合物在两种样品片制剂上的铺展系数随着表面自由能的增加而降低。在固化过程中，粉末铸造膜的穿刺强度和伸长率增加。固化时间对机械性能的影响取决于增塑剂的含量。
结论
将 TEC 和 PEG 3350 掺入 Eudragit L 100-55 粉末涂料配方中改善了成膜性能。粉末铸造膜的力学性能测试表明，随着聚合颗粒融合的标准，即固化过程中伸长率和穿刺强度均增加，在高增塑剂水平下，成膜过程更快。
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