Pharmacodynamic equivalence study of two preparations of eye drops, containing dorzolamide in healthy volunteers

Abstract

Introduction: Dorzolamide 20mg/ml eye drops (dorzolamide hydrochloride (CAS: 120279-96-1)) is a topical carbonic anhydrase inhibitor indicated for the reduction of elevated intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension. The aim: The aim of the present study was to assess the pharmacodynamic equivalence of two preparations of eye drops containing 20 mg dorzolamide (CAS: 120279­96-1). Method: The study was conducted as a monocentric, observer-blinded, randomized, single dose, single period study in thirty-six healthy volunteers. Each volunteer received in a random way after measurement of IOP intraocular pressure a single dose of 1 drop of the test product in the conjunctival sac of one eye and 1 drop of the reference drug in the conjunctival sac of the other eye. Measurement of intraocular pressure (IOP) of both eyes was performed on day 1 of each study period pre-dose and 2 h post dosing by means of Goldmann applanation tonometry. The two-sided 95% confidence interval was calculated for the difference of the primary target parameter (absolute decrease in intraocular pressure 2 h post dose). Results: The statistical evaluation demonstrated a decrease in the IOP of 3.10 mmHg for the eye treated with the test formulation (dorzolamide 20mg/ml eye drops) and 3.23 mmHg for the eye treated with the reference formulation. The mean difference was -0.13 mmHg. The 95% confidence interval was between -0.65 and 0.40 mmHg and thus entirely within the pre-defined equivalence range (±1.5 mmHg). Conclusion: Both formulations showed comparable results obtained at a time probably equal to the maximum effect concerning the primary target parameter lowering of intraocular pressure 2h post dose. The safety profile of both preparations showed no difference.

Keywords

• dorzolamide
• eye drops
• intraocular pressure