Animal corneas as tools for the testing of antiviral compounds

As a number of viruses can be titrated on corneas of various animals, the corneal method was used to detect antiviral activity of some derivatives of thiazolidine and related compounds with a low toxicity. In herpetic infections of rabbit cornea, 2-(1-isopropylidene)azino-3-(beta-D-ribofuranosyl)-methoxycarbonylmethylenethiazolidine-4-one showed for a mean of 2.1 greater activity than IDU. In piglet corneas, lesions produced by adenovirus type 8 were inhibited by a mean of 3.4 log CID50 by 5-(2,3,5-tribenzoyl-beta-D-ribofuranosyl)-(2H)-tetrazol and by a mean value of 3 log CID50 by 4-(2,3,5-tri-o-benzoyl-beta-D-ribofuranosyl) thiosemicarbazide. The multiple microinoculation technique of calculating corneal infectivity allows many of the advantages of sensitivity and statistical validity usually associated only with cell culture methods to be obtained from an in vivo system. Furthermore it allows observations concerning toxicity of the drug tested on the eye. We believe that this method should form a part of the "biography" of any compound seriously considered for the ocular treatment of virus diseases. This test goes a long way in bridging the gap between in vitro tests and trials in humans.