Wyeth-Ayerst Premarin delta 8,9 component should be classified as active ingredient -- amended petition.

Executive Summary

WYETH-AYERST PREMARIN DELTA 8,9-DHES SHOULD BE CONSIDERED ACTIVE INGREDIENT, "the same as estrone sulfate and equilin sulfate," the company says in a recent letter to FDA amending its November 1994 citizen petition. In defining the components of Premarin, a February 1991 Generic Drugs Advisory Committee classified delta 8,9-dehydroestrone sulfate as a signal impurity, subject to a limit test. Wyeth-Ayerst's contention since then has been that delta 8,9-DHES should be reclassified as a required "concomitant component."