The ocular activity of a single dose of brimonidine o.2 % in solution and liposomal formulations was evaluated in 28 adult patients with recently diagnosed primary open angle glaucoma. Multilamellar liposomes were prepared from dipalmitoyl phosphatidcholine and cholesterol. Stearylamine and dicetyl phosphate were used to modify the net surface charge of liposomes. The evaluation of the performance of various formulations of the drug was assessed on the basis of the influence of the drug on the intraocular pressure. Results demonstrated that the intra-ocular activity of the drug using various liposomal formulations was greater than that of solution form. Moreover, concerning the liposomal surface charge, the drug activity was greatest for positively charged liposomes, less for neutral liposomes and least for negatively charged liposomes. This could be attributed to electrostatic attraction between the negatively charged surface of the corneal epithelial and positively charged liposomal surface.
In conclusion, it was clearly observed that liposomal ophthalmic drug delivery system seems to be a promising approach for the selective targeting of the drug.