**Author details**

Abitylguanide was applied as 1% eye drops (in saline). In each of the two trials, patients were divided in three groups: group I placebo (patients with symptomatic treatment), group II -abitylguanide 1% + symptomatic treatment, group III—patients treated with abitylguanide 1% only. Curative effect of abitylguanide was almost identical in group II and III in both trials. Moreover, the drug had a preventive effect on infection of the second eye. The abitylguanide treatment exerted a marked curative effect on the severity and duration of the disease: (1) more than twofold decrease in both trials in the number of patients with EKC form associated with keratitis; (2) five- and sixfold decrease in trial 1 an trial 2, respectively, in the incidence of severe keratitis; (3) two- and fivefold decrease in trial 1 and trial 2, respectively, in the number of patients with impaired vision; (4) twofold decrease of the healing time [61–63]. Effectivity toward AdV-induced EKC of the drug applied topically was confirmed in series of placebo controlled trials (not following the double-blind scheme) in three other ophthalmic clinics in the country, carried out in the second half of the 1980s. Pencheva et al. [64] in the Varna Medical Faculty registered marked decrease of the patients number with keratitis, twofold shortening of the healing time in abitylguanide treated patients, affection of the second

In preliminary carried out study abitylguanide manifested a very high local tolerance (1, 2

The pronounced effect of abitylguanide [65] in abovementioned trials on EKC patients served for the development and implementation in pharmaceutical industry of preparative ADENOSTATIN COLLYRIUM® (Pharmachim Ltd., Sofia) which clinical use marked favor-

The clinical use of cardiotonic steroids as anti-AdV agents needs special consideration. As digitoxin has been associated with toxicity, the use of cardiac glycosides as antivirals would be short term, in contrast to the chronic use in patients with heart diseases. Having in mind that anti-AdV agents have to be used for the treatment of severe respiratory and disseminated diseases, these drugs seem more attractive as potential agents for the topical treatment of EKC

There is no doubt that chemotherapy of AdV infections occupies leading position as a tool for anti-etiological treatment. Therefore, the development of effective anti-AdV agents is especially a big task of the scientists and clinicians. The above-presented panorama of antivirals versus AdVs and AdV-caused infections shows that a lot of work is done for the realization of this problem. The author would like to mention the main directions that determined the development of antivirals and their implementation in the clinical practice: (1) discovery of the targets in virus growth cycle for chemotherapeutic attacks—a lot of "wide" places could be pointed in the AdVs; (2) attainment in the organic chemistry—modeling of new effective molecules with anti-AdV effects among anomalous nucleosides, end especially of non-nucleoside compounds ligands of AdV proteins; (3) development of adequate methodology for antiviral testing starting from the initial in vitro screening, and application of purified AdV structural and eventually nonstructural proteins as cell-free systems (approach contributed substantially for the successful development of anti-hepatitis C drugs; as concerns the in vivo testing, in the last years, several very convenient and adequate models were described and successfully used

eye—80% in the placebo group, and 22.6% in abitylguanide treated group.

22 Adenoviruses

and 3% eye drops in saline) tested in 21 volunteers (in rabbits—till 20% eye drop).

able estimation by ophthalmologists in this country (tested in Japan, as well).

and even for the prophylaxis of persons contact to EKC patients [3].

Angel S. Galabov

Address all correspondence to: galabov@microbio.bas.bg

The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, Sofia, Bulgaria
