Cytotoxicity of five fluoroquinolone and two nonsteroidal anti-inflammatory benzalkonium chloride-free ophthalmic solutions in four corneoconjunctival cell lines

Abstract

Purpose: Epithelial disorders after eye surgery can result in visual deterioration and patient discomfort. Such disorders may be caused by drug toxicity. In the present study, we evaluated the toxicity of ophthalmic solutions, with or without benzalkonium chloride (BAK) as the preservative, used for postoperative care.

Methods: A range of commercially available antibiotic and anti-inflammatory ophthalmic solutions used postoperatively (ie, levofloxacin, moxifloxacin, gatifloxacin, norfloxacin, tosufloxacin, dibekacin, cefmenoxime, diclofenac, bromfenac, pranoprofen, betamethasone, and fluoromethorone) were assessed in three corneal cell lines and one conjunctival cell line. All antibiotic solutions were BAK free. Cell viability was determined with the 3-(4,5-dimethyl-2 thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay after cells had been exposed to the drugs for 48 h. The effects of preservatives on cell viability were also determined. Toxicity was compared using the cell viability score (CVS).

Results: Based on results of the MTT assay and CVS, the order of cell viability after exposure to the antibiotic solutions was cefmenoxime ≥ tosufloxicin ≥ dibekacin ≥ levofloxacin ≥ norfloxacin = gatifloxacin = moxifloxacin. For the anti-inflammatory solutions, the order of cell viability was betamethasone ≥ betamethasone + fradiomycin > preservative-free diclofenac ≥ preservative-free bromfenac >> 0.02% fluoromethorone ≥ 0.1% fluoromethorone = diclofenac + preservative = bromfenac + preservative = pranoprofen. The anti-inflammatory drugs were more toxic than the antibiotics. The toxicity of antibiotic drugs against ocular surface cells was dependent on the pharmaceutical components of the solution, whereas that of the anti-inflammatory drugs was dependent on both the pharmaceutical components and the preservatives.

Conclusion: Postoperative drug-induced epitheliopathy may be caused primarily by anti-inflammatory drugs. CVS is useful in comparing the cytotoxicity of different drugs.

Keywords: cornea; eye; preservative; toxicity.

Figure 1

Effects of antibiotic ophthalmic solutions on the viability of cultured rabbit corneal epithelial cells (RC-1 and SIRC), bovine corneal epithelial cells (BCE), and human conjunctival cells (Chang) after 48 h exposure. Data are the mean ± SD. Cefmenoxime was the least toxic. The cell viability score was determined and the order of cell viability was cefmenoxime ≥ tosufloxicin ≥ dibekacin ≥ levofloxacin ≥ norfloxacin = gatifloxacin = moxifloxacin (Table 1).

Figure 2

Effects of anti-inflammatory ophthalmic solutions on the viability of cultured rabbit corneal epithelial cells (RC-1 and SIRC), bovine corneal epithelial cells (BCE), and human conjunctival cells (Chang) after 48 h exposure. Data are the mean ± SD. Data for benzalkonium chloride (BAK)-free drugs are indicated by the dotted lines. Cell viability was greater in all BAK-free solutions, except for Diclod, compared with solutions containing BAK. The cell viability score was determined and the order of viability was betamethasone ≥ betamethasone + fradiomycin > preservative-free diclofenac ≥ preservative-free bromfenac >> 0.02% fluoromethorone ≥ 0.1% fluoromethorone = diclofenac + preservative (Diclod) = bromfenac + preservative (Bronuck) = pranoprofen.

Figure 3

Effects of preservatives on the viability of cultured rabbit corneal epithelial cells (RC-1 and SIRC), bovine corneal epithelial cells (BCE), and human conjunctival cells (Chang) after 48 h exposure. Data are the mean ± SD. Benzalkonium chloride and polysorbate were shown to have dose-dependent cytotoxic effects.