Development of the cholestosome, a novel delivery system made exclusively from cholesteryl esters

Abstract

AbstractA novel vesicular drug delivery system has been created using only cholesteryl esters. The uncharged nature of the esters requires a formulation process that uses energy, in the form of sonication, to facilitate the cholesteryl esters formation into vesicles. The nature of the material choices renders the vesicles resistant to pH degradation between a pH of 2 and 10. Storage condition at 4°C for 9 months shows a stability of encapsulated materials as well as vesicles. The formulation process is a modified reverse phase method in which the esters are dissolved in an organic solvent, which is then removed and the aqueous component is then added with sonication in a temperature‐controlled water bath. A wide variety of materials can be encapsulated in these vesicles, which are called cholestosomes. Delivery of the cholestosome‐encapsulated materials is a function of the ester component structure and not the encapsulated molecule. Once encapsulated, the vesicles deliver the materials into cells. The potential for oral availability was explored using chylomicrons. Successful delivery of the cholestosome encapsulated into chylomicrons has enhanced the effectiveness of delivery to cells. Analytical methods have been developed to analyze the materials chosen from the cholesteryl esters as well as the encapsulated materials.Practical Applications: The creation of the cholestosome vesicle opens up completely new areas for encapsulating and delivering materials. The cholesteryl ester structure that makes up the vesicles is impervious to pH and bile salts, making cholestosomes ideal for oral delivery of drugs, such as oral insulin. Intracellular delivery of cholestosome vesicles enables multiple applications, from killing latent infections to preventing viral replication (irrespective of the virus) and delivering nucleic acid therapeutics to cure genetic disease. These vesicles pass the blood–brain barrier and could be used for treatments of Alzheimer's and related neurodegenerative disease. Cholestosomes can also be used in cosmetic formulations as the vesicles pass the dermis. They even could be used in food applications as the materials are considered generally regarded as safe.