Ram H N Aswatha, Lachake Prachiti, Kaushik Ujjwal, Shreedhara C S
Department of Pharmacognosy, Manipal College of Pharmaceutical Sciences, Manipal University, Manipal - 576 104, Karnataka, India.
Pharmacognosy Res. 2010 Sep;2(5):304-8. doi: 10.4103/0974-8490.72329.
Floating tablets prolong the gastric residence time of drugs, improve bioavailability, and facilitate local drug delivery to the stomach. With this objective, floating tablets containing aqueous extract of liquorice as drug was prepared for the treatment of Helicobacter pylori and gastric ulcers.
The aqueous extract of liquorice was standardized by HPTLC. Tablets containing HPMC K100M (hydrophilic polymer), liquorice extract, sodium bicarbonate (gas generating agent), talc, and magnesium stearate were prepared using direct compression method. The formulations were evaluated for physical parameters like diameter, thickness, hardness, friability, uniformity of weight, drug content, buoyancy time, dissolution, and drug release mechanism. The formulations were optimized on the basis of buoyancy time and in vitro drug release.
The diameter of all formulations was in the range 11.166-11.933 mm; thickness was in the range 4.02-4.086 mm. The hardness ranged from 3.1 to 3.5 kg/cm(2). All formulations passed the USP requirements for friability and uniformity of weight. The buoyancy time of all tablet formulations was less than 5 min and tablet remained in floating condition throughout the study. All the tablet formulations followed zero-order kinetics and Korsemeyer-Peppas model in drug release.
The optimized formulation was found to be F6 which released 98.3% of drug in 8 h in vitro, while the buoyancy time was 3.5 min. Formulations containing psyllium husk, sodium bicarbonate and HPMC K100M in combination can be a promising for gastroretentive drug delivery systems.
漂浮片可延长药物在胃内的停留时间，提高生物利用度，并便于药物在胃部局部给药。基于此目的，制备了含甘草水提取物的漂浮片用于治疗幽门螺杆菌和胃溃疡。
采用高效薄层色谱法对甘草水提取物进行标准化。使用直接压片法制备含有羟丙基甲基纤维素K100M（亲水性聚合物）、甘草提取物、碳酸氢钠（产气剂）、滑石粉和硬脂酸镁的片剂。对制剂的物理参数进行评估，如直径、厚度、硬度、脆碎度、重量均匀度、药物含量、漂浮时间、溶出度和药物释放机制。基于漂浮时间和体外药物释放对制剂进行优化。
所有制剂的直径在11.166 - 11.933毫米范围内；厚度在4.02 - 4.086毫米范围内。硬度范围为3.1至3.5千克/平方厘米。所有制剂均符合美国药典对脆碎度和重量均匀度的要求。所有片剂制剂的漂浮时间均小于5分钟，且在整个研究过程中片剂保持漂浮状态。所有片剂制剂在药物释放方面均遵循零级动力学和 Korsemeyer - Peppas模型。
发现优化后的制剂为F6，其在体外8小时内释放了98.3%的药物，而漂浮时间为3.5分钟。含有车前子壳、碳酸氢钠和羟丙基甲基纤维素K100M的组合制剂对于胃滞留药物递送系统可能具有前景。
