Tablets and Other Solid Dosage Forms for Systemic Oral Mucosal Drug Delivery

Abstract

In recent years, interest in oral mucosal drug delivery has been growing rapidly due to the many advantages this route offers such as rapid onset of drug action and ability to bypass first-pass metabolism in the gastrointestinal (GI) tract and liver. With these advantages, however, there are also specific challenges with this route of administration such as reduced contact surface area between the drug solution and oral membrane and the small amount of solvent (saliva) that can be used to dissolve the drug; these challenges can limit the amount of drug absorbed. Despite these difficulties, a number of oral transmucosally delivered products have been developed and marketed that are more effective and sometimes safer than conventional dosage forms. Clinical studies that directly compare conventional dosage forms with oral transmucosally delivered products have shown that patients prefer the latter due to the aforementioned advantages. This chapter focuses on the formulation and performance of solid dosage forms commonly used in oral transmucosal delivery. Basic principles in oral transmucosal drug delivery have been presented and new developments have been discussed in depth. Examples of formulation technologies and clinical performance from successful and widely known oral transmucosally delivered products, such as Fentora®/Effentora®, Actiq®, Zydis ® Selegiline, and Commit® lozenge are presented together with comparisons to conventional dosage forms. Together, this body of data shows that oral transmucosal drug delivery is an attractive route of administration that is safe, effective, and convenient to the patient. In certain situations, for example, when the metabolites have undesirable side effects, oral transmucosal drug delivery can prove to be significantly safer than conventional routes of administration. New formulation strategies such as the use of permeation enhancers, effervescence agents, and dynamic pH variability are available that can favorably manipulate and direct drug delivery across the oral mucosa. Thus, there is large scope in the further development of strategies for oral transmucosal drug delivery; such a scope could be applied to hitherto unexplored molecules.