Here is another example of expanding application of inkjet technology. Last week Hewlett Packard announced that it had used its ink-jet printer cartridge technology to create a patch that releases drugs through the skin in a controlled and painless way.

The company said it has entered into a licensing agreement with Crospon, an Irish medical device developer, who will manufacture the invention and make it available to pharmaceutical firms as soon as 2010.

Patches that deliver medication through skin has long been around, for instance smoking patches. However they didn’t work for drugs that can’t be absorbed through the skin, and could only provide continuous flow of just one medication.

The new patch acts very much like a ink cartridge that squirts different colors. It uses micro-hypodermic needles controlled by a microprocessor to deliver particular drugs below the skin several at specified doses and time. This allows for timing sensitive medication delivery, which means it can be used for the treatment of diabetes, cardiac disease or hormonal imbalances.

The price of the patch is expected to be relatively inexpensive because it is based on the same technology that has long been employed in HP ink cartridges.