The results of studies in healthy volunteers indicate that a new iontophoretic transdermal system, designed to deliver sumatriptan (Zelrix; NuPathe Inc.) for migraine, is well tolerated and achieves blood concentrations similar to those reached using other modes of administration, researchers report in the current issue of the journal Headache.

In an iontophoretic system, a substance bearing a low electrical current is propelled forward. In this case, the method was used as a drug delivery system, in which sumatriptan was propelled across the skin barrier.

Dr. Mark Pierce of NuPathe Inc, Conshohocken, Pennsylvania and colleagues point out that sumatriptan, and other drugs of the same class, approved as oral formulations in the US, but this may not be the ideal route of administration for many migraineurs. Sumatriptan is additionally available as a nasal spray and subcutaneous injection (injection just below the skin).

To investigate how the Zelrix transdermal delivery system performs, the researchers conducted an open-label crossover study in 25 male and female volunteers. They received each of five treatments: sumatriptan 100 mg oral tablets, sumatriptan 6 mg subcutaneously, sumatriptan 20 mg nasal spray, Zelrix I or Zelrix II. (The Zelrix patches contained different amounts of gel but each delivered 6 mg of sumatriptan).

Both patches achieved plasma sumatriptan concentrations of 10 nanograms per milliliter in about 30 minutes. Maximum concentrations for Zelrix I and II (24.8 ng/mL and 23.1 ng/mL) were intermediate between those for oral (51.6 ng/mL) and nasal (12.5 ng/mL) formulations. The patches were well tolerated, and skin reactions were mild and most resolved within 72 hours.

In light of these findings, the researchers conclude that “iontophoretic technology may prove beneficial for a large segment of the migraine population based upon fast, consistent delivery of drug and avoidance of common gastrointestinal disturbances associated with migraine.”

SOURCE: Headache, June 2009.