Khoh-Reiter Su, Jessen Bart A
Drug Safety Research and Development, Pfizer Inc, San Diego, CA 92121, USA.
BMC Ophthalmol. 2009 Jul 28;9:5. doi: 10.1186/1471-2415-9-5.
Benzalkonium chloride (BAC) is a common preservative used in ophthalmic solutions. The aim of this study was to compare the cytotoxic effects of BAC-containing ophthalmic solutions with a BAC-free ophthalmic solution using an organotypic 3-dimensional (3-D) corneal epithelial model and to determine the effects of latanoprost ophthalmic solution and its BAC-containing vehicle on corneal thickness in a monkey model.
The cytotoxicity of commercially available BAC-containing ophthalmic formulations of latanoprost (0.02% BAC) and olopatadine (0.01% BAC) was compared to that of BAC-free travoprost and saline in a corneal organotypic 3-D model using incubation times of 10 and 25 minutes. To compare the extent of differentiation of 3-D corneal cultures to monolayer transformed human corneal epithelial (HCE-T) cell cultures, expression levels (mRNA and protein) of the corneal markers epidermal growth factor receptor, transglutaminase 1 and involucrin were quantified. Finally, latanoprost ophthalmic solution or its vehicle was administered at suprapharmacologic doses (two 30 microL drops twice daily in 1 eye for 1 year) in monkey eyes, and corneal pachymetry was performed at baseline and at weeks 4, 13, 26 and 52.
In the 3-D corneal epithelial culture assays, there were no significant differences in cytotoxicity between the BAC-containing latanoprost and olopatadine ophthalmic solutions and BAC-free travoprost ophthalmic solution at either the 10- or 25-minute time points. The 3-D cultures expressed higher levels of corneal epithelial markers than the HCE-T monolayers, indicating a greater degree of differentiation. There were no significant differences between the corneal thickness of monkey eyes treated with latanoprost ophthalmic solution or its vehicle (both containing 0.02% BAC) and untreated eyes.
The lack of cytotoxicity demonstrated in 3-D corneal cultures and in monkey studies suggests that the levels of BAC contained in ophthalmic solutions are not likely to cause significant direct toxicity to epithelium of otherwise normal corneas.
苯扎氯铵（BAC）是眼科溶液中常用的防腐剂。本研究的目的是使用器官型三维（3-D）角膜上皮模型比较含BAC的眼科溶液与不含BAC的眼科溶液的细胞毒性作用，并确定拉坦前列素眼科溶液及其含BAC的赋形剂对猴模型角膜厚度的影响。
在角膜器官型3-D模型中，使用10分钟和25分钟的孵育时间，将市售含BAC的拉坦前列素（0.02% BAC）和奥洛他定（0.01% BAC）眼科制剂的细胞毒性与不含BAC的曲伏前列素和生理盐水的细胞毒性进行比较。为了比较3-D角膜培养物与单层转化人角膜上皮（HCE-T）细胞培养物的分化程度，对角膜标志物表皮生长因子受体、转谷氨酰胺酶1和内披蛋白的表达水平（mRNA和蛋白质）进行了定量。最后，以超药理剂量（每天2次，每次30 μL滴眼，单眼给药1年）给猴眼滴注拉坦前列素眼科溶液或其赋形剂，在基线以及第4、13、26和52周进行角膜测厚。
在3-D角膜上皮培养试验中，含BAC的拉坦前列素和奥洛他定眼科溶液与不含BAC的曲伏前列素眼科溶液在10分钟或25分钟时间点的细胞毒性均无显著差异。3-D培养物比HCE-T单层表达更高水平的角膜上皮标志物，表明分化程度更高。用拉坦前列素眼科溶液或其赋形剂（均含0.02% BAC）治疗的猴眼与未治疗眼的角膜厚度无显著差异。
3-D角膜培养和猴研究中均未显示出细胞毒性，这表明眼科溶液中所含BAC的水平不太可能对正常角膜上皮造成显著的直接毒性。
