Transmucosal delivery systems

The purpose of this overview chapter is to provide perspectives in the current status and future prospects of controlled release drug delivery. This is accomplished by examining various delivery systems from a mechanistic point of view, exploring applications of these systems, and discussing relevant biopharmaceutical parameters. A major section of this book is devoted to fundamental issues and applications of transdermal and transmucosal delivery systems (Chapter 6,8,17-23). Other developing systems of future potential... 

Transdermal Delivery Systems. Transdermal delivery of drugs over extended periods of time for systemic therapy has received significant attention. The importance and future prospects of this field are further reflected in the section on Transdermal and Transmucosal Delivery Systems (Chapters 17-23). Intact human skin, once thought to be an impermeable barrier, was realized as a potential portal of entry for systemic drug therapy only recently. 

The market for oral transmucosal delivery systems is still very small, and its growth over the next five years will depend on the dmgs which are approved for delivery by this route and the prevalence of the conditions for which they are intended. 

No.l2, June 2000, p.l 191-6 TRANSMUCOSAL DELIVERY SYSTEMS FOR CALCITONIN REVIEW... 

Torres-Lugo, M. and Peppas,N. A. (2000).Transmucosal delivery systems for calcitonin A review. Biomaterials, 21,1191-1196. 

The nitrates are available in various forms (eg, sublingual, transmucosal, translingual spray, and inhalation). Some adverse reactions are a result of the metiiod of administration. For example, sublingual nitroglycerin may cause a local burning or tingling in the oral cavity. However, die patient must be aware that an absence of this effect does not indicate a decrease in the drug s potency. Contact dermatitis may occur from use of die transdermal delivery system. 

Figure 15 Transmucosal fentanyl drug delivery system Actiq .

Within the last 10, years several new compounds were launched in the field of non-steroidal antiinflammatory drugs (NSAIDs) with a clear focus on cyclooxygenase type 2 selective compounds. In the field of opioids on the other hand no new drugs have passed phase III clinical trials. In this field innovation has been achieved through new pharmaceutical formulations of known drugs such as transdermal systems, e.g. buprenorphine patch, transmucosal systems, e.g. fentanyl lollipop, or rectal delivery systems containing e.g. morphine. These were developed in order to reduce opioid side effects, but also to overcome pharmacokinetical limitations, in particular to prolong compliance and duration of action. 

Iontophoresis techniques (i.e., the use of electric current to facilitate transdermal delivery) have also been advocated as a way to enhance transdermal opioid delivery to the systemic circulation.11 By varying the amount of electric current, iontophoresis may ultimately allow the patient to control the rate of transdermal administration of the opioid.10,76,78 Finally, certain opioids such as fentanyl can be administered systemically via lozenges or a lollipop that dissolves in the mouth (transmucosal delivery), or via nasal spray (intranasal administration).21,54 It will be interesting to see if these newer methods of administration will gain widespread acceptance in the future. 

Ingestion and initial fragmentation of food occurs in the oral cavity. There has recently been considerable interest in this site for the systemic delivery of drag moieties. The possibility of transmucosal delivery via the mucous membranes of the oral cavity is discussed in Chapter 7. 

Recently, adhesive patches have been developed for transmucosal delivery. Such systems are discussed further in Section 7.7. 

However, it is important to note that the system does not actually facilitate oral transmucosal delivery per se, rather it allows rapid release of the drug in the mouth. The drug is then washed down with the saliva for subsequent absorption in the gastrointestinal tract. 

Figure 7.4 Cydot matrix system for the transmucosal delivery of melatonin (Courtesy of 3M Pharmaceuticals)...

Sun J-B, Holmgren J, Czerkinsky C (1994) Cholera toxin B subunit An efficient transmucosal carrier-delivery system for induction of peripheral immunological tolerance. In Proc. Natl. Acad. Sci. USA 91 10795-10799. 

Wide array of pharmaceutical dosage forms such as pellets, granules, sustained/controlled release, oral fast dissolving system, targeted release such as transdermal, transmucosal, and transungual delivery system and implants. 

Madhav, N.V.S. Semwal, R. Semwal, D.K. Semwal, R.B. Recent trends in oral transmucosal drug delivery systems An emphasis on the soft palatal route. Expert Opin. Drug Deliv. 2012, 9 (6), 629-647. 

Ilium, L. and Davis, S. (2005) Chitosan as a delivery system for the transmucosal administration of drugs, in Polysaccharides. Structural Diversity and Functional Versatility, 2nd edn (ed. S. Dumitriu), Marcel Dekker Publ., New York, pp. 643-660. 

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