title: High-throughput HPLC-MS/MS method to determine ibandronate in human plasma for pharmacokinetic applications.
abstract: A sensitive high-throughput liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the quantification of ibandronate in human plasma. In a previous study, we have analyzed alendronate in urine samples of subjects treated at therapeutic dosages, using a derivatization approach; a similar derivatization was adapted and improved to determine ibandronate in plasma. The bisphosphonate was isolated from the biological matrix by liquid-liquid extraction, and derivatized with trimethylsilyldiazomethane prior to separation on a reversed-phase column (Supelco Discovery HSC18) and detection on a quadrupole-linear ion trap mass spectrometer (API 4000 QTrap). Various parameters of extraction and derivatization were optimized in order to get adequate recovery, high derivatization yield and minimal ion suppression; a deuterated analogue, d3-ibandronate, was used as internal standard. The transitions 376.1-->114.2 and 379.1-->61.0 were acquired to monitor ibandronate and d3-ibandronate derivatives, respectively. A multiplexing LC system made possible the overlapping of two chromatographic runs, thus the interval between injections being reduced to only 2min, a very short analysis time for compounds of this class. The method was fully validated over the quantification range 0.2-175.0ng/ml, allowing an appropriate evaluation of the plasma concentrations of ibandronate, expected at therapeutic dosage, as proved by application to a pharmacokinetic study. A good linearity over the selected range (r>0.99), accuracy and precision within +/-15% of the target values and a recovery over 50% were obtained.
authors.affiliation: Pharma Serv Int'l SRL, 52 Sabinelor Str., 5th District, 050853 Bucharest, Romania.
authors.forename: Isabela
authors.initials: I
authors.lastname: Tarcomnicu
authors.forename: Mihaela Cristina
authors.initials: MC
authors.lastname: Gheorghe
authors.forename: Luigi
authors.initials: L
authors.lastname: Silvestro
authors.forename: Simona Rizea
authors.initials: SR
authors.lastname: Savu
authors.forename: Irina
authors.initials: I
authors.lastname: Boaru
authors.forename: Ariana
authors.initials: A
authors.lastname: Tudoroniu
mesh_terms: D050071:Bone Density Conservation Agents / Q000097:blood / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004164:Diphosphonates / Q000097:blood* / Q000493:pharmacokinetics; D004355:Drug Stability; D006801:Humans; D000077557:Ibandronic Acid; D016014:Linear Models; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates; D000077557:Ibandronic Acid