Michael tears down an iontophoresis patch to see what’s inside. He writes:
I don’t mean to brag, but I have a really great mom. Sadly though, last week she twisted her ankle quite badly. According to her physical therapist, the injury caused damage to one of the nerves in her leg. So, in addition to the more traditional PT remedies (cold and hot packs, stretching exercises, etc), he prescribed a disposable iontophoresis patch, pictured here, for the administration of the anti-inflammatory drug dexamethasone. And the day after she was done with it, my mother, knowing of my fascination with electronics, mailed it to me for disassembly.
So just what is iontophoresis? (And why isn’t it spelled ionophoresis? That letter “t” really feels out of place to me…) Well, it is a method for drug delivery which utilizes direct electrical current to “push” charged ions through a patient’s skin – no needle required. It works based on the simple principle that like charges repel and opposite charges attract. So, if we have a drug which can be ionized – either positively or negatively charged – we can apply a like charge to the delivery electrode, and an opposing charge to the skin itself. This difference in electrical potential (aka voltage) will cause the charged drug ions to flow into the skin. Cool, right?
Check out the whole write-up here. Some pretty clever stuff and great analysis by Michael!