Buccal Delivery of Curcumin to Address Its Poor Gastrointestinal Stability

Abstract

Curcumin has numerous health benefits but has low bioavailability in the digestive system due to its low aqueous solubility, high metabolism rate caused by bile (from the liver), and degradation of curcumin under the basic conditions of the small intestine. The alternative way of delivering curcumin into the systemic circulation is through the buccal mucosa, but curcumin has to be delivered quickly before it undergoes degradation under the neutral conditions of the mouth. Oral disintegrating films (ODFs) are investigated as a pathway to release nanoparticles across the buccal mucosa to improve bioavailability. Chitosan, a mucoadhesive polymer, is used to coat nanoparticles. Pregelatinized starch (PGS), granular hydroxypropyl starch (GHS), hydroxypropylmethylcellulose (HPMC) and polyvinyl alcohol (PVA) are mucoadhesive polymers used in films, and propylene glycol (PG) as plasticizer. Mass, thickness, percentage recovery, surface pH, disintegration time and dissolution are assessed for each film. All films have a surface pH of around 6.7, making them non-irritant. Films with formulation of GHS and HPMC has highest maximum percentage dissolution, and has high percentage recovery, giving high drug load. It has released more curcumin than other films in the same time frame, allowing for curcumin to be released quickly. The average disintegration time for it is 53 minutes, which is long for ODFs. More drug can be released across the buccal mucosa over a longer timeframe. Films with PVA may be the thinnest and lightest, but break upon handling, making them hard to apply onto the buccal mucosa and unsuitable as an oral film.