This hyperlinked journal article is a review of microneedles for drug and vaccine delivery. I believe we've passed this around before, but I don't think we've featured it on the blog. There are certainly still lessons we can learn from it.
We can channel this primary information into our particular application. It talks about each choice of microneedle geometry, material, and drug delivery type. Some drug delivery devices are better suited for other applications. For example,fully dissolvable poly-saccharide subtrate microneedles are very effective for drug delivery in flu vaccine applications and limits biohazardous waste. However, that application requires a 10 minute set time in which the patch is constantly in contact with the arm. While this is fine for drug delivery, that 10 minutes of patch contact may disrupt the measurable outcome of the scratch test and render the assay useless. Those are the sorts of choices that we can propose and mark of the list. We have spoken in general and sometimes more specific terms about these choices and think we have an idea of what suits our project, but we should give this article rigorous consideration so that we may make the most appropriate choice. Perhaps there are recently developed geometries and subtrates that competitors neglected or weren't priviledge to. We have the advantage that the competitors that have approached this problem had to make final design choices earlier, where current research and manufacturing capacity could now be better suited.
Take a look at the paper! Future posts will have a more comprehensive analysis.
In case you missed the hyperlink: http://drugdelivery.chbe.gatech.edu/Papers/2012/Kim%20Adv%20Drug%20Deliv%20Rev%202012.pdf
Can you remind us again why waiting 10 minutes is unacceptable? How long would you have to wait for the wheal results if you removed the patch vs left it in?
ReplyDeleteLooks like I need to set Blogger to update on comment.
ReplyDeleteIt's not the testing time that's the problem; it's the time the patch has to stay on. For example, hollow microneedles deliver very fast, and there wouldn't need to be a patch left on the skin.
It's just an idea, really. The patch might even be a fairer deal. The idea I had was that a patch left on the skin might irritate the reaction area, especially if you are working with a kid that might want to touch the new thing on their arm. If you have to do this with dissolvable microneedles, then that is an extra design consideration. The 10 minutes is to ensure that the microneedles fully dissolve and all of the allergen is delivered. Otherwise, there might be undissolved, undelivered allergen left in the tips when retracted. I'm not sure how much of a problem this is going to be. Literature won't answer that question directly, but it can tell us about how long a dissolvable microneedle will take to dissolve, leaving the rest of the parameters to us.