Emerging strategies for enhancing buccal and sublingual administration of nutraceuticals and pharamaceuticals

As a relatively convenient route of administration, oral route of drug delivery can be used for topical and systemic administration. However, conventional oral administration through gastro-intestinal (GI) tract results in excessively reduced drug delivery for some drugs due to the presence of metabolic enzymes and the first-pass effect of the liver, necessitating a search for other routes of drug administration. The oral mucous adhesive administration (also called oral mucosal administration) refers to a drug delivery system in which the carrier made of bio-adhesive materials adheres to the mucosa, and is an alternate route of oral administration. Herein, the loading compounds can release from the carrier continuously and bypass the degradative effect of metabolic enzymes and the first-pass effect suffered during GI absorption. This article introduces the structure of oral mucosa and the basic conditions of mucosal adhesion, and generally reviews the bio-adhesive materials commonly used for oral mucosal administration and summarizes some of the oral mucosal adhesion products that have been released into the market.