Nanoparticles and Liposomes in Ophthalmic Drug Delivery

Abstract

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.