Screening for Corticosteroids in Topical Pharmaceuticals by HPLC With a Scanning Ultraviolet Detector*

A screening procedure was developed for the detection of 49 corticosteroids in topical pharmaceutical products. These products were analyzed by reversed-phase HPLC using two gradient systems: a linear gradient of 18–82% acetonitrile over 12 min and a linear gradient of 38–88% methanol over 12 min. Although all corticosteroids were not resolved during a single 12-min gradient analysis, a peak retention time from a sample analysis was usually sufficient to limit an unknown to 1–3 probable corticosteroids. Steroids unresolved with the first gradient system were resolved with the second one, with the exception of three steroid pairs. Assignments based on retention times were supported by spectra provided by a rapid scanning ultraviolet detector. Two extraction procedures were developed to isolate corticosteroids from both water-soluble and lipid-soluble sample components. When applied to a variety of topical formulations, the two extraction methods eliminated most of the sample excipients, recovered corticosteroids in high yield, and allowed for detection to a level of 0.001% of the sample.