title: Measurement of neosaxitoxin in human plasma using liquid-chromatography tandem mass spectrometry: Proof of concept for a pharmacokinetic application.
abstract: Neosaxitoxin, a member of the saxitoxin family of paralytic shellfish poisoning toxins, has shown potential as an effective, long-acting, anesthetic. We describe the development and validation of a highly sensitive method for measurement of neosaxitoxin in human plasma using liquid chromatography tandem mass spectrometry (LC-MS/MS) and provide evidence for its use in a human pharmacokinetic study. Samples were prepared using cation exchange solid phase extraction followed by hydrophilic interaction liquid chromatography and MS/MS detection in positive electrospray ionization mode. Multiple reaction monitoring was used to monitor neosaxitoxin (m/z 316.17>220.07) and the internal standard analogue decarbamoylneosaxitoxin (m/z 273.12>180.00). The method was validated for lower limit of quantification, precision, accuracy, linearity and matrix effect. The stability of neosaxitoxin in plasma matrix at various storage conditions was also investigated. Standard curves for calibration were linear (r>0.995) across the assay calibration range, 10 to 1000pg/mL. The analytical measurable range of the assay was 10-10,000pg/mL in plasma matrix. This method has demonstrated excellent sensitivity demonstrating a lower limit of quantification in human plasma of 10pg/mL. The mean, inter-batch variation was <5.2% across the concentration range 30 to 800pg/mL. This method was successfully used in a phase 1 trial to investigate the pharmacokinetic profile of neosaxitoxin in humans following the intravenous administration of the drug at a range of doses up to 40μg. We conclude that our high-sensitivity method for measurement of neosaxitoxin in human plasma is capable of supporting future clinical trials.
authors.affiliation: Department of Laboratory Medicine, Perioperative and Pain Medicine, Boston Children's Hospital, 300 Longwood Ave., Boston, MA, United States. Electronic address: roy.peake@childrens.harvard.edu.
authors.forename: Roy W A
authors.initials: RW
authors.lastname: Peake
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, 601 Elmwood Avenue, Box 608, Rochester, NY 14642, United States.
authors.forename: Victoria Y
authors.initials: VY
authors.lastname: Zhang
authors.affiliation: Department of Laboratory Medicine, Perioperative and Pain Medicine, Boston Children's Hospital, 300 Longwood Ave., Boston, MA, United States.
authors.forename: Nina
authors.initials: N
authors.lastname: Azcue
authors.affiliation: Department of Laboratory Medicine, Perioperative and Pain Medicine, Boston Children's Hospital, 300 Longwood Ave., Boston, MA, United States.
authors.forename: Christina E
authors.initials: CE
authors.lastname: Hartigan
authors.affiliation: Department of Laboratory Medicine, Perioperative and Pain Medicine, Boston Children's Hospital, 300 Longwood Ave., Boston, MA, United States.
authors.forename: Aida
authors.initials: A
authors.lastname: Shkreta
authors.affiliation: Department of Laboratory Medicine, Perioperative and Pain Medicine, Boston Children's Hospital, 300 Longwood Ave., Boston, MA, United States.
authors.forename: Jasmina
authors.initials: J
authors.lastname: Prabhakara
authors.affiliation: Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, 300 Longwood Ave., Boston, MA, United States.
authors.forename: Charles B
authors.initials: CB
authors.lastname: Berde
authors.affiliation: Department of Laboratory Medicine, Perioperative and Pain Medicine, Boston Children's Hospital, 300 Longwood Ave., Boston, MA, United States.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Kellogg
mesh_terms: D000293:Adolescent; D000328:Adult; D000777:Anesthetics / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D057230:Limit of Detection; D008297:Male; D009466:Neuromuscular Blocking Agents / Q000097:blood*; D012530:Saxitoxin / Q000031:analogs & derivatives* / Q000097:blood; D052616:Solid Phase Extraction / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods*; D055815:Young Adult
chemical_list: D000777:Anesthetics; D009466:Neuromuscular Blocking Agents; D012530:Saxitoxin; C034902:neosaxitoxin
keywords: LC–MS/MS; Neosaxitoxin; Pharmacokinetcs