Evaluation of cytotoxicity of various ophthalmic drugs, eye drop excipients and cyclodextrins in an immortalized human corneal epithelial cell line.
OBJECTIVE
An immortalized human corneal epithelial cell line (HCE) was tested as a screening tool for prediction of topical ocular irritation/toxicity by pharmaceuticals


METHODS
Effects of various drugs, excipients and cyclodextrins (CDs) on viability of HCE cells were evaluated using two in vitro cytotoxicity tests, 3-(4,5-dimethlthiazol-2-yl)-205-diphenyl tetrazolium bromide (MTT) dye reduction assay and propidium iodide assay.


RESULTS
Mitochondrion-based MTT test was a more sensitive indicator of cytotoxicity than the plasma membrane-based propidium iodide test. The tests revealed following cytotoxic rankings for ophthalmic drugs: dipivefrin > timolol > pilocarpine approximately equal to dexamethasone; for excipients: benzalkonium chloride (BAC) > sodium edetate (NA2 EDTA)>polyvinyl alcohol (PVA) > methylparaben; and for CDs :alpha- CD > dimethyl beta-cyclodextrin (DM-beta-CD) > sulfobutyl ether beta-cyclodextrin ((SBE)7m-beta-CD approximately equal to hydroxypropyl-beta-cyclodextrin (HP-beta-CD) > lambda CD. In consideration of the in vivo clinical situation, the short exposure time (5 min) is more relevant even though toxic effects of some test substances were seen only after longer exposure time (30 and 60 min).


CONCLUSIONS
Immortalized HCE cells are a promising tool for rapid cytotoxicity assays of ocular medications. The cell line is potentially useful in predicting the in vivo coreal toxicity of ocularly applied compounds.
Department of Pharmaceutical Chemistry, University of Kuopio, Finland.
P
P
Saarinen-Savolainen
T
T
Järvinen
K
K
Araki-Sasaki
H
H
Watanabe
A
A
Urtti
D002461:Cell Line, Transformed; D002470:Cell Survival / Q000187:drug effects; D003315:Cornea / Q000166:cytology / Q000187:drug effects*; D003505:Cyclodextrins / Q000633:toxicity*; D004341:Drug Evaluation; D004847:Epithelial Cells / Q000187:drug effects; D005079:Excipients / Q000633:toxicity*; D006801:Humans; D009883:Ophthalmic Solutions / Q000633:toxicity*
D003505:Cyclodextrins; D005079:Excipients; D009883:Ophthalmic Solutions