An ocular bioavailability comparison in rabbits of prednisolone acetate after repeated topical applications formulated as a high-viscosity gel and as an aqueous suspension.

Author(s): Johansen S, Rask-Pedersen E, Prause JU

Affiliation(s): Eye Pathology Institute, University of Copenhagen, Denmark.

Publication date & source: 1996-06, Acta Ophthalmol Scand., 74(3):259-64.

Publication type:

To increase contact time between drug and ocular surface and thus improve the ocular bioavailability, we used the high-viscous, water-soluble polymer carbomer Leogel (carbomer 0.5%). We compared the bioavailability of prednisolone acetate 0.5% given in 1) Leogel using fusidic acid 1% with that obtained using 2) aqueous sulfacetamide sodium 10% as vehicle. We applied the drugs to Copenhagen white rabbits as repeated topical applications (gel preparation: twice daily; aqueous preparation: four times daily) for one week. Dosis regimen was chosen according to earlier investigations (Johansen et al. 1995). Prednisolone concentrations in cornea, conjunctiva and aqueous humour were shown to be higher using the Leogel vehicle than using the aqueous suspension. Fusidic acid and sulfacetamide sodium values were compared with values from a single application (Johansen et al. 1995). Fusidic acid reached higher concentration levels in cornea, conjunctiva and aqueous humour after repeated applications than after a single application. Sulfacetamide sodium concentrations did not rise when applied four times daily for one week. Leogel increases the ocular bioavailability of substance(s) in the gel and allows lower drug concentrations and/or application frequencies.