The concept of drug delivery through the skin for systemic indications is now widely accepted. However, the number of drugs which may be delivered by the transdermal route is limited by the barrier properties of the skin. Conventional transdermal therapy is limited to small, potent and lipophilic drugs. Iontophoresis is one strategy devised to facilitate transdermal drug delivery. Ionophoresis may be defined as the facilitated movement of ions across a membrane, e.g. the skin. In order to deliver a positively charged drug across the skin, a solution of, for example, a cationic drug is placed at the positive electrode where it is repelled and then attracted towards a negative electrode place elsewhere on the body. Delivery of positively charged compounds is generally easier than negatively charged compounds as the skin itself possesses a net negative charge.

Although drugs may be delivered iontophoretically across the skin to exert a local effect, e.g. anaesthesia, current iontophoresis research is primarily focused on systemic drug delivery. Iontophoresis is a non-invasive drug delivery system with no trauma or risk of infection and is therefore a useful alternative to drug administration by injection.

The major commercial iontophoretic electrode, trans-Q^a, is designed such that charge is delivered to a hydrogel pad loaded with a drug solution. The hydrogel is moistened with a small volume of a previously prepared drug solution, squeezing the pad firmly several times, and allowing 60 seconds for complete hydration to take place. This procedure is obviously prone to error since the medication must be prepared correctly at the point of use and the gel pad must also be fully hydrated. 

Work is ongoing at the BEST Centre in the School of Pharmacy, QUBto develop novel, bioadhesive, drug- containing electrodes for use in iontophoretic drug delivery. The design of the electrode overcomes many of the problems associated with present iontophoretic electrode designes. It is envisaged that this novel electrode may be used as a generic iontophoretic drug delivery system for a wide range of charged drugs.

In parallel with this research, the BEST Centre at QUB is currently designing a system for the detection of bacterial biofilm formation. Bacteria have a natural tendency to adhere to surfaces.

Following adhesion bacteria replicate and than secrete and become encapsulated within exopolymeric materials to from a microbial biofilm. Formation of microbial biofilm on surfaces causes problems in the food and energy industries. In the brewing industry, contamination of ‘python’ tubing can cause fouling of beer, whilst biofilm formation on pipelines reduces heat transfer efficiency. The use of electrodes that will detect biofilm formation on inert surfaces will ensure greater economic efficiency for industrial processes as appropriate cleaning processes may be initiated prior to the establishment of a mature biofilm. For the pharmaceutical industry, in particular, there are benefits associated with the validation of cleaning processes, an important part of pharmaceutical good manufacturing practice.