ocular dorzolamide nanoliposomes for prolonged iop reduction: in-vitro and in-vivo evaluation in rabbits

dorzolamide ophthalmic drop is one of the most common glaucoma medications but it has a short residence time in the eye. the aim of this study is to develop ocular dorzolamide hcl nanoliposomes (drz – nanoliposomes) and to evaluate their potential use for the treatment of ocular hypertension. nanoliposomes were prepared using reverse-phase evaporation vesicle (rev) and thin layer hydration (tlh) method with 7:3 and 7:4 molar ratios of phosphatidylcholine:cholesterol. the physicochemical properties of the formulations were investigated. formulations with 7:4 lipid ratio were evaluated in terms of drug release, physical stability and ex vivo permeation through the excised albino rabbit cornea. the rabbits in groups of 6 were treated with selected drz – nanoliposomes or dorzolamide solution or marketed dorzolamid preparation (biosopt®) and intraocular pressure (iop) was monitored. formulations with 7:4 molar ratio entrapped greater amount of drug compared to those with 7:3 lipid components ratio. drz – nanoliposomes with 7:4 lipid ratio showed more transcorneal permeation than dorzolamide solution (p<0.05); and the formulation prepared by tlh method exhibited higher permeability than that prepared by rev method (p<0.05). the selected drz – nanoliposomes showed greater iop lowering activity and a more prolonged effect compared to dorzolamide solution and biosopt®. drz – nanoliposomes prepared by tlh method with 7:4 ratio showed promising results as a candidate for the treatment of ocular hypertension.