Sparidans R W, den Hartigh J, Beijnen J H, Vermeij P
Department of Clinical Pharmacy and Toxicology, Leiden University Hospital, The Netherlands.
J Chromatogr B Biomed Sci Appl. 1997 Aug 15;696(1):137-44. doi: 10.1016/s0378-4347(97)00226-0.
A sensitive method for the determination of pamidronate disodium [(3-amino-1-hydroxypropylidene)bisphosphonate, APD] in urine has been developed and validated. The procedure involves a triple co-precipitation with calcium phosphate, solid-phase extraction on a quaternary ammonium column, derivatization with 1-naphthylisothiocyanate and ion-pair liquid-liquid extraction. From the two reaction products, naphthylthiocarbamyl-APD is converted into the other, naphthylcarbamyl-APD, by an oxidative desulphuration with hydrogen-peroxide prior to analysis by ion-pair HPLC and fluorescence detection at 285/390 nm. The method has a coefficient of variation of 7% for the intra-assay precision of 99 ng ml-1 APD and 11% for the inter-assay precision. The lower limit of quantification is 3 ng ml-1 APD in 2.5 ml of human urine.
