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BACKGROUNDZinc oxide (ZnO) nanoparticles are manufactured worldwide in large quantities for use in wide range of applications including pigments and cosmetic manufacturing. Although ZnO is chemically inert, ZnO nanoparticles can cause negative health effects. However, the mechanism involved in ZnO induced genotoxicity and carcinogenicity has not been clearly defined and are poorly studied in vivo.

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Cefixime trihydrate (CT) is a third-generation cephalosporin antibiotic and is used in the management of various infections caused by Gram +ve as well as Gram – ve bacteria. It has a plasma half-life of 3-4 h. It has poor oral bioavailability due to hepatic first pass metabolism. Hence, an attempt was made to develop CT mucoadhesive tablets for buccal delivery to avoid first-pass metabolism and improved oral delivery. CT mucoadhesive tablets developed using HPMC K4M, Na-CMC, guar gum and chitosan as rate controlling polymers and mucoadhesive agent, respectively and compressed by direct compression method. The prepared CT mucoadhesive tablets were evaluated for hardness, weight variation, thickness, friability, drug content uniformity, assay, mucoadhesive strength and in vitro release. From the results, all the evaluated parameters were within the pharmacopoeial limits. The in-vitro dissolution studies indicated that the CTmucoadhesive tablets formulation (F2) showed 99.7±1.4 % of drug release after 8 h and chose as the optimized formulation. The kinetic models suggest that the drug release follows Higuchi’s kinetics and tablets drug release was controlled by a diffusion mechanism.

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.