The effect of synthesized 5-R-1H-benzo[d]imidazole-2-thiol derivatives on intraocular pressure in normal and pathological conditions

and do not have a resorptive effect is a topical task for the treatment of glaucoma. Eighteen derivatives of 5-R-1H-benzo[d]imidazole-2-thiols were synthesized and studied for ophthalmic hypotensive activity in animals with normal intraocular pressure and in animals with dexamethasone-induced ophthalmic hypertension. Materials and Methods: Ophthalmohypotensive activity was studied by tonometry with the TonoVet veterinary tonometer in 90 intact and experimental sexually mature mongrel rats weighing 250-350g before and after instillation of solutions of the studied compounds. Local irritant effects were determined by performing a conjunctival test using 25 guinea pigs. Results: The most active compound among the 5-R-1H-benzo[d]imidazole-2-thiol derivatives was compound 1a, which reduced the ophthalmotonus in normotensive animals by 31.37%, exceeding the effect of the reference drugs timolol (-26.84%) and melatonin (-30.95%), and in rats with dexamethasone-induced glaucoma – by 23.74%, similar to melatonin (-23.72%), but inferior to timolol (-29.75%). It was found that substance 1a has no local irritant effect. It was revealed that at the screening concentration (4 mg/mL), compound 1a has a systemic effect, at lower concentrations, the ophthalmohypotensive effect decreases, the latent period increases, and the severity of the resorptive effect decreases. Conclusion: The most active compound, 1a, was found to have demonstrated in vivo IOP-lowering activity when administered as a single instillation at a concentration of 0.4% (4 mg/mL) in ophthalmonormotensive animals and animals with steroid-induced glaucoma. Compound 1a was shown to have no local irritant effect.