Faculty of Medicine, University of Toronto, Toronto, Ont.
Can J Ophthalmol. 2012 Feb;47(1):55-61. doi: 10.1016/j.jcjo.2011.12.004.
To determine whether brand-name glaucoma drops differ from generic equivalents in bottle design, viscosity, surface tension, and volume in North America.
Experimental study.
We studied 5 bottles each of 11 kinds of glaucoma drops.
Density-based calculations of drop volume were assessed using 0.1 mg analytic balance. Viscosity was measured using rotational rheometery. Bottle tip diameter was measured using 0.05 mm Vernier calipers. Surface tension was measured using a Fisher Scientific (Ottawa, ON) tensiometer.
For the American brand-name Timoptic XE, the average drop volume was 38 ± 3.1 μL versus 24 ± 1.5 μL of Timolol GFS (p < 0.0001). For the Canadian brand-name Timoptic XE, the average drop volume was 42 ± 4.0 μL versus 25 ± 2 μL of timolol maleate EX (p < 0.0001). The Canadian brand-name Timoptic drop volume was 28 ± 1.4 μL versus 35 ± 1.9 μL Apo-Timop (p < 0.01). At a 0.1 per second shear rate, the viscosity of Canadian Timoptic XE was 20 times higher than that of its generic equivalent, whereas the viscosity of American Timoptic XE differed from the generic by a factor of 100. The surface tension of Canadian Timoptic XE was 31% higher than that of the generic (p < 0.001), whereas the surface tension of American Timoptic XE was 21% higher than that of the generic (p < 0.001). The bottle tips of the Canadian and American Timoptic XE measured about 3.5 times larger than those of their generics.
American and Canadian Timoptic XE eye drops vary significantly from the generics in drop volume, viscosity, surface tension, and bottle tip. Canadian brand-name Timoptic delivered significantly smaller drop volumes than generic Apo-Timop. Careful consideration should be given to drop viscosity and bottle design when generic ophthalmic products are evaluated for interchangeability and market entry.
确定在北美的瓶身设计、黏性、表面张力和容量方面，名牌青光眼滴眼液是否与仿制药存在差异。
实验研究。
我们研究了 11 种青光眼滴眼液的每种各 5 瓶。
使用 0.1mg 分析天平对滴液体积进行基于密度的计算。使用旋转流变仪测量黏性。使用 0.05 毫米游标卡尺测量瓶嘴直径。使用 Fisher Scientific（渥太华，安大略省）张力计测量表面张力。
对于美国名牌 Timoptic XE，平均滴液量为 38±3.1μL，而 Timolol GFS 为 24±1.5μL（p<0.0001）。对于加拿大名牌 Timoptic XE，平均滴液量为 42±4.0μL，而 timolol maleate EX 为 25±2μL（p<0.0001）。加拿大名牌 Timoptic 的滴液量为 28±1.4μL，而 Apo-Timop 为 35±1.9μL（p<0.01）。在 0.1 秒/秒的剪切速率下，加拿大 Timoptic XE 的黏性是其仿制药的 20 倍，而美国 Timoptic XE 的黏性则是其仿制药的 100 倍。加拿大 Timoptic XE 的表面张力比仿制药高 31%（p<0.001），而美国 Timoptic XE 的表面张力比仿制药高 21%（p<0.001）。加拿大和美国 Timoptic XE 的瓶嘴尺寸比其仿制药大约 3.5 倍。
在滴液量、黏性、表面张力和瓶嘴方面，美国和加拿大的 Timoptic XE 滴眼液与仿制药有明显差异。加拿大名牌 Timoptic 的滴眼剂量明显小于仿制药 Apo-Timop。在评估仿制药的可互换性和市场准入时，应仔细考虑滴眼剂的黏性和瓶身设计。
