Loaded dose and delivered dose
A patch’s loaded dose and the dose delivered into tissue are different measurements. Material may remain on the device, stay on the skin surface or enter the tissue. A measurement of recovered material does not establish whether it retains biological activity.
Studying delivery in human skin
Excised human skin allows local delivery and tissue response to be studied outside the body. Culture conditions influence how long those observations remain meaningful. A published long-term human skin platform reports extended observation under its tested conditions. Its results concern that platform.
Skin samples also differ by donor, body site and handling. Repeated measurements from one sample do not establish how a result varies across people.
What the tissue can tell us
A tissue experiment can show local entry, release and response under its conditions of observation. It does not reproduce systemic circulation or establish vaccine protection.
These distinctions guide how we read delivery studies: where the material was found, what was measured and which conclusions the experimental system can support.
Research note · 14 October 2026. The diagram explains general dose measurements; it is not an experimental result.