Absorption, drug buccal cavity

Orally administered drugs are mainly absorbed in the small intestine (duodenum, jejunum, and ileum) and in the large intestine (colon) however, other regions, such as buccal cavity, stomach, and rectum, also can be considered potential sites for drug absorption. The various anatomical and physiological characteristics of each segment are briefly described in Table 1. 

One of the most common in vivo methods used to assess the permeability of the buccal mucosa is the buccal absorption test of Beckett and Triggs [13]. In this test, a known volume of a drug solution is introduced into the oral cavity of a subject, who swirls it around for a specified period of time and then expels it. The subject then rinses his or her mouth with an aliquot of distilled water or buffer solution, and the expelled drug solution and rinse are combined and analyzed for drug content. The difference between the initial and final drug concentration in the solution is assumed to be the amount of drug taken up into the oral mucosa. 

Currently, most strategies for buccal delivery of peptide drugs have focused on the application of excipients that would shorten the time of absorption and adhere drugs to a local site on the mucosa, thus decreasing exposure to proteolytic degradation and possible release of drug back into the mouth cavity. This strategy has been utilized in the buccal delivery of insulin, enkephalin, and testosterone [37, 70]. 

Mouthwashes, toothpastes and other preparations are introduced into the oral cavity for local prophylactic and therapeutic reasons. It is not known to what extent components of these formulations are absorbed and give rise to systemic effects. The absorption of drugs through the oral mucosa, however, provides a route for systemic administration which avoids exposure to the gastrointestinal system. Dmgs absorbed in this way bypass the liver and have direct access to the systemic circulation. The sublingual, buccal and gingival... 

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