pH responsive liposome-in-microsphere formulations for drug delivery to the colon

A formulation has been developed that incorporates sub micron liposomes in pH responsive polymer microspheres for drug delivery to the ileocaecal junction of the GI tract. Eudragit S100 microspheres were produced using a double emulsion technique and used to encapsulate liposomes. To withstand the solvent used within the microsphere production route, the liposomes were coated with chitosan. The model drug 5-ASA was incorporated into the liposomal formulations with release being explored in simulated GI tract conditions.