Tennent Institute of Ophthalmology, Gartnavel General Hospital, Glasgow, UK.
Eye (Lond). 2012 May;26(5):734-41. doi: 10.1038/eye.2012.25. Epub 2012 Mar 2.
Preservatives in ophthalmic preparations are known to cause ocular surface damage. Excipients can also contribute to oxidative stress in the compromised ocular surface. We evaluated commonly used topical glaucoma medications to ascertain pH levels and the intrinsic presence of free radicals.
Samples of 27 topical glaucoma preparations were analysed for total free radical presence using a Randox Kit for total antioxidant status. Analytical grade indicator paper was used to ascertain pH levels.
Free radical concentrations for these 27 glaucoma preparations ranged from 0 to 4.54 mmol/l, with a median value of 0.66 mmol/l (mean value of 0.662 mmol/l, SD 0.839). Levels of pH ranged from 4.0 to 7.4, with a median value of 6.5 (mean 6.252, SD 0.826). There was no evidence of a direct correlation between these two variables (r=0.232, P=0.275).
This study is the first to document the range of pH and concentrations of free radicals intrinsically present in commonly used glaucoma medications. Long-term exposure to preservatives, free radicals, and pH levels could all contribute to ocular surface damage. The effect of excipients could be responsible for patient intolerance when changing products in the compromised ocular surface.
眼用制剂中的防腐剂已知会引起眼表损伤。赋形剂也会导致受损眼表的氧化应激。我们评估了常用的局部青光眼药物，以确定 pH 值和自由基的固有存在。
使用 Randox 试剂盒评估 27 种局部青光眼制剂中总自由基的存在，以评估总抗氧化状态。使用分析级指示剂试纸确定 pH 值。
这 27 种青光眼制剂中的自由基浓度范围为 0 至 4.54mmol/L，中位数为 0.66mmol/L（平均值为 0.662mmol/L，标准差为 0.839）。pH 值范围为 4.0 至 7.4，中位数为 6.5（平均值为 6.252，标准差为 0.826）。这两个变量之间没有直接的相关性（r=0.232，P=0.275）。
这项研究首次记录了常用青光眼药物中固有存在的 pH 值和自由基浓度范围。长期接触防腐剂、自由基和 pH 值都可能导致眼表损伤。在受损眼表更换产品时，赋形剂的影响可能导致患者不耐受。
