DIPHENCYPRONE IS NOT DETECTABLE IN SERUM OR URINE FOLLOWING TOPICAL APPLICATION

Diphencyprone is a potent contact sensitizer in widespread use for tre atment of alopecia areata. It is currently not known whether this comp ound is absorbed following topical application. This is important, sin ce little is known regarding potential toxicity. We therefore analysed serum and urine samples following application of at least 0.5 ml of a 1% solution of diphencyprone to the scalp of patients under treatment for alopecia areata. Serum samples were obtained over 8 h following t reatment and 24-h urine collections were performed. The threshold for detection was 2 ng, and the assay gave an accurate linear response for samples of serum and urine containing known concentrations of diphenc yprone. Blood and/or urine samples were obtained from a total of 18 su bjects. Diphencyprone was not detected in any sample of serum or urine from the subjects. These data suggest that diphencyprone is not absor bed following application to the skin.