UCL Discovery

Abstract

The possibility of drug targeting to the colon by using a coating comprising amylose in glassy form has been studied. Amylose is a naturally-occurring polysaccharide and possesses the ability to form gels and films. This ability has been used to formulate a coating by spraying it on to drugs in pellet form. However, amylose film strength is poor in water due to swelling and, under simulated gastro-intestinal conditions, allows drug release. With the incorporation of Ethocel® into the coat, drug release in vitro was suppressed over a period of 12 h. Further evaluation of the drug coated pellets was carried out in vitro in a batch culture fermenter containing foecal inoculum, simulating large bowel conditions. The coating was fermented and the drug released. The in vivo performance of coated C glucose pellets in eight healthy human volunteers was evaluated using gamma scintigraphy and CO excretion in breath. Gamma scan photographs showed the mean arrival time of the pellets to be 3.5 h in the coecum (range 2.5 to 4.7 h). Breath CO was detected 3.7 h post-dosing and was not significant (1% recovery) until 6.4 h. Breath CO was not apparent before pellets had reached the coecum, with a delay of 2.9 h between coecum arrival and significant CO release.