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The success of oral drug delivery has been challenged by poor drug solubility and/or absorption,first-pass metabolism,and food effects which lead to variable/improper bioavailability of drugs.Lipid based drug delivery systems (viz.,proliposomes) found to be very promising in enhancing the oral bioavailability through improved gastrointestinal solubility and absorption.Further,PEGlyated (polyethylene glycol coated) liposomes reported to be resistant to their digestion by bile salts,provide improved gastrointestinal (GI) stability and absorption and,enhance the cell membrane permeability by inhibiting P-gp (P-glycoprotein) efflux.Thus,there is a tremendous scope for developing PEGylated oral proliposomal drug delivery systems.Proliposomes were developed for a candidate anti-cancer drug,exemestane (a poorly soluble drug with improper/variable bioavailability) and PEGylation was carried out using different mole% of DSPE-PEG 2000.Proliposomes were evaluated for dissolution and,permeability characteristics using rat intestine,parallel artificial membrane permeability assay (PAMPA) and Caco-2 models.PEG coating found to have a significant influence on the dissolution and permeability characteristics of exemestane from proliposomal formulations.Surprisingly,PEGylated proliposomes were successful in enhancing the permeability in different models studied irrespective of the differences in the permeation mechanisms operating in these models.PEGylated proliposomes found to be promising drug delivery systems for improved oral delivery.