Abstract
Delivering vaccines into skin offers an appealing alternative to needle-based administration for immunization. Besides the benefit of directly delivering vaccines into immunologically competent skin, cutaneous immunization provides the benefits of patient compliance and dose sparing. Vaccine delivery into skin, however, is limited by the barrier of stratum corneum, the outermost layer of skin. A variety of technologies have been developed to permeabilize the stratum corneum to enhance vaccine entry into skin. This review provides a summary of some of these technologies that are based on mechanical disruption of stratum corneum. These include liquid jet injectors, powder injectors, ultrasound, microneedles, abrasive devices, thermal ablation and lasers. An overview of the principles of these technologies, their ability to deliver vaccines and experience in clinical applications is discussed.
