A significant improvement in the safety of modern vaccines has been the development of subunit vaccines, as these are composed of very well-defined and highly pure components, often recombinant proteins. However, since protein-based antigens in general are weakly immunogenic by themselves, co-administration of adjuvants is required to induce potent and persistent specific immune responses. In recent years, there has been substantial progress in the discovery of new efficient adjuvants for subunit vaccines that are often classified into delivery systems and immunopotentiating compounds that constitute pathogen-associated molecular patterns, such as the toll-like receptor ligands. The combination of delivery systems and immunopotentiators has appeared to represent extraordinarily good adjuvants due to concomitant enhanced antigen delivery and potent stimulation of innate immunity. Many of these adjuvants are of a particulate nature and mimic the structure and/or composition of microbes in a reductionist fashion. Examples are liposomes, polymeric nanoparticles, emulsions and virus-like particles. However, there are a substantial number of pharmaceutical challenges associated with the subunit vaccine development process due to the complex nature of the antigen-adjuvant combinations. These challenges will be presented and discussed in this book. The objective of the book is to compile the concepts essential for the understanding of the pharmaceutical science and technology associated with the delivery of subunit vaccines. The books goal is to provide a comprehensive overview of the scientific and regulatory challenges facing scientists who research and develop subunit vaccines. The scope of the book is wide. It is written in a manner that will enlighten newcomers to the field (e.g., PhD students or experienced scientist switching fields) yet provide an in-depth knowledge that would benefit a skilled worker in the field. "

This comprehensive volume compiles the concepts essential for the understanding of the pharmaceutical science and technology associated with the delivery of subunit vaccines. Twenty-one chapters are divided into four main parts: (I) Background; (2) Delivery Systems for Subunit Vaccines; (3) Delivery Routes, Devices and Dosage Forms; and (4) Pharmaceutical Analysis and Quality Control of Vaccines. Part one provide a basic background with respect to immunology and general vaccine classification. In part two, it presents representative types of vaccine delivery systems individually with focus on the physicochemical properties of the systems and their significance for the immune response they stimulate. These delivery systems include aluminum adjuvants, emulsions, liposomes, bilosomes, cubosomes/hexosomes, ISCOMs, virus-like particles, polymeric nano- and microparticles, gels, implants and cell-based delivery systems. Following these chapters, part three addresses the challenges associated with vaccine delivery via specific routes of administration-in particular subcutaneous, intramuscular, oral, nasal, pulmonary, transdermal and vaginal administration. Furthermore, the specific administration routes are discussed in combination with device technologies relevant for the respective routes as well as dosage forms appropriate for the device technology. Finally, the fourth part concerns pharmaceutical analysis and quality control of subunit vaccines.