Bioadhesive polymers, permeation enhancers and types of dosage forms for buccal drug delivery

The buccal delivery is defined as the drug administration through the mucosal membranes lining the cheeks (buccal mucosa). The main impediment to the use of many hydrophilic macromolecular drugs as potential therapeutic agents is their inadequate and erratic oral absorption. Based on our current understanding of biochemical and physiological aspects of absorption and metabolism of many biotechnologically produced drugs, they cannot be delivered effectively through the conventional oral route. Because after oral administration many drugs are subjected to pre-systemic clearance extensive in the liver, which often leads to a lack of significant correlation between membrane permeability, absorption and bioavailability. Difficulties associated with the parenteral delivery and poor oral bioavailability provided the impetus for exploring alternative routes for the delivery of such drugs. This review covers the advantages, disadvantages of buccal delivery, drug and excipient selection especially bioadhesive polymers and permeation enhancers, and further a list of drugs developed as various dosage forms for buccal route of administration. Keywords: Buccal delivery, bioadhesive/mucoadhesive, permeation enhancer, dosage forms.