The problem is with the transdermal release test. They used a polydimethylsiloxane (PDMS) membrane to simulate human skin for studying how chlorophyll passes through.
But PDMS is a synthetic silicone membrane. It’s very different from real skin, especially ulcerated skin. Real skin has a tough outer layer (stratum corneum), which is the main barrier. An ulcer means this barrier is broken or completely missing. PDMS membrane doesn’t have this complex structure; it’s more like a simple, uniform filter.
So, the release profile they got (which follows the Ritger-Peppas model) probably only shows how chlorophyll moves through their film and the PDMS membrane. It doesn’t really tell us how it would behave on a real wound, where there is no skin barrier and there are body fluids, enzymes, and different pH. The release could be much faster and different in a real situation.
Because of this, their conclusion about the “dual mechanism of erosion and diffusion” for transdermal behavior might not be correct for the actual application on skin ulcers. The model they used is just not a good representative for damaged skin.
This is a major point because the whole purpose of the film is to work on ulcers, but the test doesn’t properly simulate that condition. They should have used a better model, like real animal skin or at least a more advanced skin model that includes the lack of a barrier.