title: A general approach for the quantitative analysis of bisphosphonates in human serum and urine by high-performance liquid chromatography/tandem mass spectrometry.
abstract: Bisphosphonates are extremely hydrophilic and structurally similar to many endogenous phosphorylated compounds, making their selective extraction from serum or urine very challenging. Many bisphosphonates lack strong chromophores for sensitive UV or fluorescence detection. We report here the first general approach to enable sensitive and selective quantitation of N-containing bisphosphonates by liquid chromatography/tandem mass spectrometry (LC/MS/MS) following derivatization with diazomethane. The novelty of the strategy lies in performing the derivatization on silica-based anion-exchange sorbents as an integrated step in the sample purification by solid-phase extraction (SPE). The 'on-cartridge' reaction with diazomethane not only led to higher efficiency of derivatization, but also enabled a more discriminatory recovery of the drug's derivatives. The derivatized bisphosphonates demonstrated improved chromatographic separation and increased sensitivity of the detection. The general applicability of the approach was demonstrated by validation of bioanalytical methods for risedronate and alendronate in human serum and urine. Sensitivity was achieved at the pg/mL level with merely 100-200 microL of sample.
authors.affiliation: MDS Pharma Services, 621 Rose Street, Lincoln, NE 68502, USA.
authors.forename: Lee S
authors.initials: LS
authors.lastname: Zhu
authors.forename: Veniamin N
authors.initials: VN
authors.lastname: Lapko
authors.forename: Jean W
authors.initials: JW
authors.lastname: Lee
authors.forename: Yousef J
authors.initials: YJ
authors.lastname: Basir
authors.forename: Chris
authors.initials: C
authors.lastname: Kafonek
authors.forename: Richard
authors.initials: R
authors.lastname: Olsen
authors.forename: Chad
authors.initials: C
authors.lastname: Briscoe
mesh_terms: D019386:Alendronate / Q000032:analysis* / Q000737:chemistry; D050071:Bone Density Conservation Agents / Q000032:analysis* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D003978:Diazomethane / Q000737:chemistry; D012968:Etidronic Acid / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry; D006801:Humans; D000068296:Risedronic Acid; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry
chemical_list: D050071:Bone Density Conservation Agents; D003978:Diazomethane; D000068296:Risedronic Acid; D012968:Etidronic Acid; D019386:Alendronate