Dexamethasone Disodium Phosphate Penetration Into the Human Aqueous Humor After Topical Application

Purpose: To study the amount of steroids that is found in the aqueous humor after topical administration of dexamethasone solution eye-drops and dexamethasone suspension eye-drops. Materials and methods: One hundred seventeen consecutive patients of both genders 18 years or older, candidates for cataract surgery were randomly assigned to one of three groups. Fifty-one patients (group A) received a single instillation of a suspension containing tobramicin 0.3% mg/ml + dexamethasone 0.1% mg/ml; 56 patients (group B) received a single instillation of a solution containing tobramicin 0.3% mg/ml + dexamethasone 0.1% mg/ml; 10 patients (group C), control group, did not receive any drops. Samples were taken immediately before surgery from the anterior chamber and dexamethasone levels were measured using gas chromatography/mass spectrometry. Results: The mean dexamethasone concentrations were 0.56 μM (min 0.00, max 3.25) in group A and 0.15 μM (min 0.00, max 2.93) in group B. Dexamethasone was not detected in samples from group C. Conclusions: Dexamethasone suspension gives concentrations of steroids in the aqueous humor approximately three times higher than with dexamethasone solution drops.