Development and Evaluation Of Liposomes for Posterior Ophthalmic Drug Delivery

Abstract

Diabetic retinopathy and Age related macular degeneration are major causes of blindness nowadays. The standard therapy for these diseases is the monthly or twice in a month intravitreal injection of anti-VEGF agents. But sight threatening complications are observed because of these therapies. Topical eye drops in the form of liposomal dispersion is non-invasive mode of treatment. Liposomes act as a non-toxic and biocompatible vesicular nanocarriers which can be used to encapsulate active pharmaceutical ingredients to deliver sustained and targeted delivery. It is reported that in the comparison of cornea, conjunctiva and sclera has many folds higher paracellular space and provide facility to permeate water soluble molecules. It is hypothesized that anionic lipid will provide more diffusion due to negatively charge of sclera and cationic lipid will retain on the epi-scleral region because of electrostatic interactions. First pre-formulation study done for the gradient identification of salt and based upon that ammonium sulphate salt identified as a gradient for active loading. After that particle size-based study carried out and against hypothesis, particle size achieved from 55 to 120 nm. Based upon that anionic, cationic and neutral charged liposomes were prepared with 0.5,1,1.5 mg/ml loading capacity and characterized for particle size, zeta potential, entrapment efficiency and in-vitro release. Entrapment efficiency of drug in to liposomes varied from 80 to 100%. It was found that as particle size of liposomes decreased, slow drug release was observed in in-vitro study.