Nanoparticles And Liposomes In Ophthalmic Drug Delivery

The drainage and ocular distribution of nanoparticles and liposomes was investigated ysing the labelling of the nanoparticle polymer with 14C and the binding of a tracer, 111In-oxine, on to the particles and to the liposomes. The longest precorneal half-life was observed with positively charged liposomes yielding an about 3-fold increase in comparison to a simple solution. The half-life in the inner canthus was prolonged from 5 min to about 20 min. In the inner canthus, nanoparticles had the longest half-life. About 1 % of the initial nanoparticle dose adhered to the corneal and conjunctival surfaces for over 6 hours. While a lower ophthalmic absorption of the lipophilic drug progesterone was observed, a 1.4-fold higher efficacy of the more hydrophilic drug pilocarpine was obtained after binding to nanoparticles as determined by miosis measurements.