CLINICAL PHARMACOLOGY
Corticosteroids suppress the inflammatory response to a variety of inciting agents of a mechanical, chemical, or immunological nature. They inhibit edema, cellular infiltration, capillary dilatation, fibroblastic proliferation, deposition of collagen and scar formation associated with inflammation. Placebo-controlled clinical studies demonstrated that VEXOL® 1% Ophthalmic Suspension is efficacious for the treatment of anterior chamber inflammation following cataract surgery.
In two controlled clinical trials, VEXOL® 1% Ophthalmic Suspension demonstrated clinical equivalence to 1% prednisolone acetate in reducing uveitic inflammation. In a controlled 6-week study of steroid responsive subjects, the time to raise intraocular pressure was similar for VEXOL® 1% Ophthalmic Suspension and 0.1% fluorometholone given four times daily.
As with other topically administered ophthalmic drugs, VEXOL® 1% (rimexolone ophthalmic suspension) is absorbed systemically. Studies in normal volunteers dosed bilaterally once every hour during waking hours for one week have demonstrated serum concentrations ranging from less than 80 pg/mL to 470 pg/mL. The mean serum concentrations were approximately 130 pg/mL. Serum concentrations were at or near steady state after 5 to 7 hourly doses. After decreasing the dosing frequency to once every two hours while awake during the second week of administration, mean serum concentrations were approximately 100 pg/mL.
The serum half-life of rimexolone could not be reliably estimated due to the large number of samples below the quantitation limit of the assay (80 pg/mL). However, based on the time required to reach steady-state, the half-life appears to be short (1 - 2 hours).
Based upon in vivo and in vitro preclinical metabolism studies, and on in vitro results with human liver preparations, rimexolone undergoes extensive metabolism. Following IV administration of radio-labeled rimexolone to rats, greater than 80% of the dose is excreted via the feces as rimexolone and metabolites. Metabolites have been shown to be less active than parent drug, or inactive in human glucocorticoid receptor binding assays.
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