What Are The Limitations Of Delivering Vaccines?

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What are the limitations of delivering vaccines nasally? Abstract Intranasal vaccinations are a developing area of research that can provide a promising alternative to the current strategy of intramuscular injections 1. In this review, the reasons for growing interest in intranasal administration are discussed, with those relating specifically to vaccinations being considered in more detail. In addition, the main limitations to nasal vaccines are reviewed, taking into account issues with the nasal mucosa and the vaccine formulation itself. Finally, nasal vaccinations that are currently available are discussed as well as the potential future developments in the field. Introduction Vaccinations are the cornerstone of preventing and…show more content…
Since then, research in this area has been driven to overcome the issues with nasal vaccines and broaden their use as viable immunological tools. Interest in Intranasal Administration The nasal route has been extensively used for topical treatments in the past, for example, in the treatment of rhinitis with antihistamines. However, due to the appealing drug absorption potential of the nasal mucosa, intranasal administration for the systemic delivery of drugs has grown in popularity, allowing it to be considered as an alternative parenteral route of administration 11. The nasal mucosa consists of pseudostratified columnar epithelium that lies on top of a highly vascularised basement membrane. The columnar cell surface possesses microvilli which extensively aid systemic absorption through a greatly increased surface area 5. The highly vascularised mucosa plays a significant role in systemic absorption as blood flow, and subsequently the concentration gradient across the membrane, has a major influence in the absorption of drugs into the systemic circulation 1. These anatomical aspects, coupled with the nasal cavity’s thin and porous endothelial membrane provide an attractive option for a range of therapeutic applications 5. An example of such an application is the administration of fentanyl. Nasal delivery of fentanyl exhibits a rapid onset of action due to the advantageous nasal anatomy and provides a Tmax of approximately 7 minutes, a
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