DIABETES TECHNOLOGY & THERAPEUTICS Volume 6, Number 3, 2004 © Mary Ann Liebert, Inc. The Effect of Preapplication of Corticosteroids on Skin Irritation and Performance of the GlucoWatch G2 ® Biographer JANET A. TAMADA, Ph.D., TARA L. DAVIS, B.S., AMY D. LEPTIEN, B.S., JONATHAN LEE, B.S., BETTY WANG, M.S., MARGARITA LOPATIN, M.S., CHARLES WEI, B.S., DON WILSON, M.S., KATHLEEN COMYNS, M.P.H., and RICHARD C. EASTMAN, M.D. ABSTRACT Skin irritation due to iontophoresis may limit the frequency of use of devices for drug de- livery or transdermal extraction of analytes of clinical interest. This study examined whether preapplication of corticosteroid preparations could reduce skin irritation from iontophoresis used by the GlucoWatch G2 ® Biographer (Cygnus, Inc., Redwood City, CA) in monitoring in- terstitial glucose levels frequently and automatically. Numerous corticosteroid preparations were screened to identify formulations that did not interfere with adhesion of the Biographer to the skin or glucose sensing. Kenalog ® (Westwood-Squibb Pharmaceuticals, Inc., Buffalo, NY) (triamcinolone acetonide) and Cortizone-10 ® Quick Shot ® (Pfizer, Inc., New York, NY) (hydrocortisone) sprays were selected and, in a double-masked, randomized, controlled trial, were applied to the forearms of 66 subjects with diabetes and allowed to dry. Biographers were applied and worn for 15 h, and home blood glucose measurements were taken every 30 min to assess accuracy. Irritation was assessed periodically by trained observers and study subjects. Skin irritation was reduced by both corticosteroid sprays, with the fraction of sub- jects who experienced moderate irritation reduced by 57% and 43% for the Kenalog and Cor- tizone-10 Quick Shot sprays, respectively. The treatment effect persisted at the 1–week as- sessment. Preapplication of these preparations did not affect the clinical utility of interstitial glucose readings. Preapplication of Kenalog or Cortizone-10 Quick Shot sprays significantly reduced skin irritation due to iontophoresis, and did not interfere with glucose measurements. This approach may enable the minority of users who experience moderate to severe skin ir- ritation to use the Biographer more frequently for diabetes management. 357 INTRODUCTION T HE DIABETES COMPLICATIONS AND CONTROL TRIAL 1 and other trials 2,3 demonstrated that intensive management of blood glucose signif- icantly reduced long-term complications of di- abetes. Frequent glucose monitoring is an es- sential component of an intensive control reg- imen, and compliance is limited because of the pain and inconvenience of traditional skin prick blood glucose testing. The GlucoWatch G2 ® Biographer (Cygnus, Inc., Redwood City, Cygnus, Inc., Redwood City, California.