Stability assays of pharmaceutical preparations by quantitative paper chromatography. II. Quantitation by spectrophotofluorometry.

A quantitative paper chromatographic method has been developed which is routinely used as a stability assay for estrogenic hormones in castor oil and tablet formulations. The method involves: (a) A separation of the estrogenic hormone from interfering degradation products. (b) The location of the estrogenic hormone on the chromatogram by the guide strip technique employing a chromogenic agent. (c) The elution of the estrogenic hormone from the chromatogram. (d) A quantitative spectrophotofluorometric analysis of the eluate. Recoveries in excess of 95% are obtained by simultaneously chromatographing replicates of standard and sample solutions on the same chromatogram. A detailed account of the procedure is presented using as examples the assay of estradiol valerate in castor oil formulations and ethinyl estradiol in tablets.