Zosano Pharma: Intracutaneous Delivery of Vaccines
Zosano Pharma Corporation is clinical stage biopharmaceutical company that has developed a proprietary microneedle system to deliver formulations of drugs and vaccines intracutaneously for the treatment of a variety of indications. Our microneedle system offers rapid onset, consistent drug delivery, improved ease of use and room-temperature stability, benefits that we believe often are unavailable using oral formulations or injections. Our microneedle system has the potential to deliver numerous vaccines for a wide variety of indications in commercially attractive markets.
Our short-wear-time system consists of an array of titanium microneedles that is coated with our proprietary formulation and attached to an adhesive. When the system is applied with our hand-held applicator, the microneedles penetrate the skin to a depth of 200 microns or less, resulting in rapid dissolution and absorption of the drug coating through the capillary bed. We believe our system enables rapid and consistent delivery of the drug, with therapeutic effect typically occurring within 30 minutes or less, and easy, pain-free administration. We focus on developing specific formulations to be administered by our microneedle system, for indications in which rapid onset, ease of use and stability offer significant therapeutic and practical advantages.
Advantages for Vaccine Delivery: The skin represents the first immunological defense barrier to outside injury and has evolved into a major immunocompetent organ. Foreign agents and antigens that penetrate the outermost stratum corneum encounter a dense network of potent antigen-presenting cells, the epidermal Langerhans cells and the dermal dendritic cells. These cells readily take up foreign antigens, migrate to the draining lymph node to present antigen fragments to resting T lymphocytes, and initiate antigen-specific immune responses. The skin, therefore, is an attractive target site for vaccine delivery, allowing the most effective immunization with the least amount of antigen. However, consistent and reproducible intradermal (ID) immunization is technically challenging and only relatively small volumes can be delivered. Therefore, vaccines are traditionally given by intramuscular (IM) or subcutaneous (SC) injection. A robust, practical, cost-effective, convenient, and efficient intracutaneous antigen delivery technology will have broad applications in the field, especially if the delivery can be achieved in a minimally invasive and painless fashion. All needs above led to the development of a novel intracutaneous microneedle delivery system, which is capable of penetrating the superficial skin barrier without pain or inconvenience. Upon application of intracutanteous microneedle delivery system using a handheld applicator, the microneedles penetrate through the superficial skin barrier layer into the epidermal/dermal layers and provide rapid and reproducible intracutaneous administration of the coated antigen, deep enough to target skin immune cells and elicit potent antibody responses.