Bioavailability of antiinflammatory drugs

Bioavailability is one of the major factors for therapeutic efficacy. The b ioavailability of antiinflammatory drugs depends on the status of the eye ( degree of inflammation, vitrectomy, aphakia) and on the drug (route of admi nistration, regimen, concentration and presentation). The bioavailability o f steroid drops increases with acetate compounds, frequency of administrati on, concentration and contact time. Peribulbar injections provide a long-de livery system but with a significant systemic diffusion. Intravitreal stero ids have only a local effect due to the very low doses injected. The bioava ilability of non steroidal antiinflammatory drugs is variable, but their ef fects are similar. Antimetabolites such as 5-fluorouracile or mitomycin C h ave short half-lives, but mitomycin C must be rinsed after use due to its t oxicity.