Kim C J
School of Pharmacy, Temple University, Philadelphia, Pennsylvania 19140, USA.
Pharm Res. 1995 Jul;12(7):1045-8. doi: 10.1023/a:1016218716951.
Simple uncoated compressed tablets with a central hole (donut-shape) are proposed to provide a constant drug release over a long period of time (> 20 hrs). The effect of hole size and drug solubility on the release kinetics is investigated.
The donut-shaped polyethylene oxide (PEO, Mw = 4 x 10(6)) tablets (600 mg and 12 mm diameter) are bored with a drill bit (3/32", 7/64", 1/8", and 5/32").
The release of theophylline from the donut-shaped tablets is zero order (80-90% release) before rapidly decreasing. As the hole size is increased from 7/64" to 5/32", the release rate increases and the release time is shortened. However, the release of theophylline from the donut-shaped tablet with a hole size of 3/32" follows the same anomalous release profile from a tablet without a hole. As drug solubility increases, the duration of linear drug release is shortened to 65-70% release followed by a severe tailing at the later stage of the release.
Donut-shaped PEO tablets with a hole provide zero-order release kinetics because the effect of the releasing surface area on the release kinetics is reduced.
提出带有中心孔（甜甜圈形状）的简单无包衣压制片，以实现长时间（>20小时）的恒定药物释放。研究了孔径和药物溶解度对释放动力学的影响。
用钻头（3/32英寸、7/64英寸、1/8英寸和5/32英寸）在直径为12毫米、重600毫克的甜甜圈形状的聚环氧乙烷（PEO，Mw = 4×10⁶）片剂上钻孔。
茶碱从甜甜圈形状片剂中的释放呈零级（释放80 - 90%），之后迅速下降。随着孔径从7/64英寸增加到5/32英寸，释放速率增加，释放时间缩短。然而，孔径为3/32英寸的甜甜圈形状片剂中茶碱的释放与无孔片剂呈现相同的异常释放曲线。随着药物溶解度增加，药物线性释放的持续时间缩短至释放65 - 70%，随后在释放后期出现严重拖尾。
带孔的甜甜圈形状PEO片剂提供零级释放动力学，因为释放表面积对释放动力学的影响减小。
