Drug delivery to the posterior segment of the eye II: development and validation of a simple pharmacokinetic model for subconjunctival injection.

The aim of this study was to develop and validate a simple pharmacokinetic model for subconjunctival injection so as to study drug delivery to the posterior segment of the eye using the subconjunctival route. Curve-fitting was performed by ModelMaker 4.0 by applying Tsuji et al.'s in vivo data. It was found that drug elimination from the vitreous chamber was slowed by the existence of a peripheral compartment. The validity of this model was ensured because it gives reasonable predictability at two additional doses. This model is invaluable in studying drug delivery to the back of the eye by subconjunctival injection.