Analysis of estrogen sulphate mixtures in pharmaceutical formulations by reversed-phase chromatography.

The relative retention times of estrogen sulphates for reversed-phase, ion-pair and argentous chromatography have been determined. Detector wavelengths of 200 nm, 200 nm and 270 nm were used, respectively. Samples are prepared by dissolution of pharmaceutical formulations in the high-performance liquid chromatography (HPLC) eluent.

Validation of liquid chromatographic method for assay of calcitriol and alfacalcidol in capsule formulations.

The validation of a liquid chromatographic procedure suitable for the determination of calcitriol and alfacalcidol in their respective formulations labeled to contain at least 0.25 micrograms drug per unit is described. The capsule content is diluted and chromatographed in 15-20 min on silica columns (5 micron) with a mobile phase of hexane-tetrahydrofuran-methylene dichloride-isopropanol (72 + 12 + 12 + 4, v/v) with detection at 254 nm.