Buccal absorption dosage form

When dealing with oral dosage forms, it is important to study the various changes occurring within the oral cavity, particularly if a buccal or sublingual formulation is being considered. Table 7 lists the changes within the oral cavity that have thus far been elucidated [124,127,138-144], It is very important to note that there is a decrease in the capillary blood supply to the oral mucosa. This may make it difficult to predict accurately the absorption rates that will occur when... 

Buccal dosage forms can be of the tablet, patch, gel, or ointment type and can be employed for local or systemic delivery. For local deliveiy, conventional dosage forms such as solutions and various types of tablets (immediate release, effervescent, etc.) are more suitable. These forms generally have uncontrolled drug release with subsequent variable absorption and short residence times, and may not provide sufficient bioavailability. Novel dosage forms such as adhesive tablets, patches, gels, and... 

A request for a waiver of in vivo B A/BE studies based on the BCS is not appropriate for dosage forms intended for absorption in the oral cavity (e.g., sublingual or buccal tablets). 

The type of dosage form that is appropriate for oral transmucosal drag delivery is dependent on whether the sublingual or buccal region is to be used as the absorption site. Physiological differences between these two regions means that they are suitable for different applications and thus different types of dosage forms. 

Iga, K. Ogawa, Y. Sustained-Release buccal dosage forms for nitroglycerin and isosorbide dinitrate increased bioavailability and extended time of absorption when administered to dogs. J. Controlled Release 1997, 49, 105-113. 

The size of the delivery system varies with the type of formulation, i.e., a buccal tablet may be approximately 5-8 mm in diameter, whereas a flexible buccal patch may be as large as 10-15 cm in area. Mucoadhesive buccal patches with a surface area of 1-3 cm are most acceptable. It has been estimated that the total amount of drug that can be delivered across the buccal mucosa from a 2-cm system in 1 day is approximately 10-20 mg.f The shape of the delivery system may also vary, although for buccal drug administration, an ellipsoid shape appears to be most acceptable. The thickness of the delivery device is usually restricted to only a few millimeters. The location of the delivery device also needs to be considered. A mucoadhesive retentive system is preferred over a conventional dosage form. A bioadhesive buccal patch would appear to be the most appropriate delivery system because of its flexibility and the area of the buccal mucosa available for its application. The maximal duration of buccal drug retention and absorption is approximately 4-6 h because food and/or liquid intake may require removal of the delivery device. 

The most utilized dosage form of NTG for the majority of this century has been the sublingual (SL) tablet. It is used to abort an imminent or actually occurring attack. Buccal absorption is rapid, offering almost instantaneous relief of sufficient duration (<30 min) for the emergency. 

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