Dissolving Microneedles as Skin Allergy Test Device.

The possibility of using dissolving microneedles (DMs) as a skin allergy test device was studied in rats. Poly-L-arginine was used as a model allergen. Dextran was used to prepare three kinds of DM array chips containing different doses of poly-L-arginine: 17.1 +/- 0.5 mu g (low-dose DM), 42.2 +/- 0.8 mu g (medium-dose DM), and 87.4 +/- 1.1 mu g (high-dose DM); each 1.0 cm(2) chip contained 300 DMs. The mean lengths of the low-, medium-, and high-dose DM were 489 +/- 3, 485 +/- 3, and 492 +/- 1 mu m and mean diameters of the base were 301 +/- 2, 299 +/- 1, and 299 +/- 2 mu m, respectively. Furthermore, for the low-, medium-, and high-dose DM, the administered doses of poly-L-arginine were estimated to be 9.3 +/- 1.9, 31.1 +/- 1.3, and 61.9 +/- 4.7 mu g and the scratching behavior per 30 min was 9.8 +/- 3.4, 60.4 +/- 8.3, and 95.7 +/- 10.6 times, respectively. These results demonstrate the dose dependence of the immunoreactivity of the poly-L-arginine DMs, suggesting that DMs can be used an alternative skin allergy device.