High-performance liquid chromatography determination of three hydroxyvitamins D3 in pharmaceutical formulations

Both partition chromatography on octadecyl bonded phase and adsorption chromatography on silica gel have been used to study (i) the separation of 1a-hydroxyvitamin D3, 25-hydroxyvitamin D3 and 1a,25-dihydroxyvitamin D3, (ii) the separation of these hydroxyvitamins D3 from their corresponding prehydroxyvitamins D3, and (iii) the separation and the quantitative determination of hydroxyvitamins D3 and prehydroxyvitamins D3 in pharmaceutical formulations.