Ocular controlled delivery of brimonidine using liposomes as a particulate carrier

The ocular activity of a single dose of brimonidine 0.2% 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

Retrobulbar vascular dysfunction in different stages of diabetic retinopathy

Colour Doppler imaging [CDI] was used in forty diabetic patients without and with different stages of diabetic retinopathy and in ten normal subjects, to determine blood flow velocities and resistive index of ophthalmic, central retinal arteries and central retinal vein. Diabetic patients had lower blood velocity and higher resistive index than normal subjects in ophthalmic and central retinal arteries. These findings were significant in patients with preproliferative and proliferative diabetic retinopathy, P<0.01 and P<0.001 respectively. In conclusion, Blood flow velocity was decreased and resistive index was increased in diabetic patients