Encapsulation of Liposomes within pH Responsive Microspheres for Oral Colonic Drug Delivery

Abstract

A novel liposome-in-microsphere (LIM) formulation has been created comprising drug-loaded liposomes within pH responsive Eudragit S100 microspheres. The liposomes contained the model drug 5-ASA and were coated with chitosan in order to protect them during encapsulation within the microspheres and to improve site-specific release characteristics. In vitro drug release studies showed that LIMs prevented drug release within simulated stomach and small intestine conditions with subsequent drug release occurring in large intestine conditions. The formulation therefore has potential for oral colonic drug delivery.

Neutralization of cholera toxin with nanoparticle decoys for treatment of cholera

“…For example, nanoparticles can be administered directly, as shown for formulations such as poly (lactic-co-glycolic acid) nanoparticles and polyacrylic acid nanoparticles to treat colitis or hypercalcemia [ 40 , 41 ]. Alternatively, nanoparticles could be loaded into capsules [ 42 , 43 ] or a pH-responsive polymer matrix for targeting to specific sections of the intestinal tract [ 44 ].…”

Stimuli‐responsive liposomes for drug delivery

“…Incorporation of CHO‐PDMAEMA into the bacterial lipid mixture produced stabilized liposomes with a pH‐sensitive functionality for stimuli‐responsive drug delivery. A liposome‐in‐microsphere (LIM) system, wherein liposomes were surrounded by a shell of Eudragit S100, a methacrylic acid copolymer, showed a pH‐dependent content release profile for potential oral colonic drug delivery . In vivo studies showed that conditions present within the large intestine (> pH 7.0) promoted the degradation of the Eudragit S100 films, thus triggering the collapse of the microspheres and release of over 85% of the encapsulated agents (5‐ASAs that are coated with chitosan), compared with <10% release from simulated stomach and small intestine conditions (pH 6.3).…”

Advances in oral nano-delivery systems for colon targeted drug delivery in inflammatory bowel disease: Selective targeting to diseased versus healthy tissue

“…demonstrated that liposomes coated with Eudragit® have superior mucoadhesion characteristics in freshly extracted pig intestinal tissue, compared to other commonly investigated polymer coatings such as chitosan and carbopol(106). The results suggest that Eudragit® coatings may enable pH-dependent release and possibly reduce formulation clearance to enhance colon targeted drug delivery.Eudragit®-coated nano-delivery systems have demonstrated favourable pH-dependent release characteristics in vitro(107,108). For example,Barea et al (2010) reported a significant reduction in drug release from Eudragit®-coated liposomes in solutions designed to simulate the pH conditions of the stomach and small intestine(109).…”