IMPROVED DETERMINATION OF THE BISPHOSPHONATE PAMIDRONATE DISODIUM IN PLASMA AND URINE BY PRECOLUMN DERIVATIZATION WITH FLUORESCAMINE, HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY AND FLUORESCENCE DETECTION

An improved method for the determination of 1-hydroxy-3-aminopropylidene-1,1-bisphosphonate (pamidronate) in human urine and plasma is described. The procedure is based on a co-precipitation of the bisphosphonates (pamidronate and 6-amino-1-hydroxypentilidene-bisphosphonate, used as internal standard) with calcium phosphate. After centrifugation the precipitate is redissolved in hydrochloric acid, followed by a second precipitation. Then the bisphosphonates are dissolved in ethylenediaminetetraacetic acid, derivatized with fluorescamine, and separated by high-performance liquid chromatography. Using fluorescence detection, the limit of quantitation for pamidronate was 0.8-mu-mol/l in plasma and 0.7-mu-mol/l in urine.