Drug targeting to the vitreous body and its peripheral tissues.

The physicochemical factors (the diffusion and partition coefficients) which control the drug transport in the vitreous body, retina, lens and posterior chamber, were measured in the in vitro experiment using isolated rabbit tissues. The diffusion coefficient in vitreous body decreased with increasing the molecular weight of drugs to the exponent of 0.34. The drugs whose molecular weight is greater than about 600 hardly penetrated across the retina/sclera membrane. The in vivo elimination profile of ganciclovir from the vitreous body following the membrane-moderated intravitreal delivery device agreed with the profiles calculated from the pharmacokinetic model, together with the model parameters determined from the present in vitro experiments.