title: Biodistribution and metabolism studies of lipid nanoparticle-formulated internally [3H]-labeled siRNA in mice.
abstract: Absorption, distribution, metabolism, and excretion properties of a small interfering RNA (siRNA) formulated in a lipid nanoparticle (LNP) vehicle were determined in male CD-1 mice following a single intravenous administration of LNP-formulated [(3)H]-SSB siRNA, at a target dose of 2.5 mg/kg. Tissue distribution of the [(3)H]-SSB siRNA was determined using quantitative whole-body autoradiography, and the biostability was determined by both liquid chromatography mass spectrometry (LC-MS) with radiodetection and reverse-transcriptase polymerase chain reaction techniques. Furthermore, the pharmacokinetics and distribution of the cationic lipid (one of the main excipients of the LNP vehicle) were investigated by LC-MS and matrix-assisted laser desorption ionization mass spectrometry imaging techniques, respectively. Following i.v. administration of [(3)H]-SSB siRNA in the LNP vehicle, the concentration of parent guide strand could be determined up to 168 hours p.d. (post dose), which was ascribed to the use of the vehicle. This was significantly longer than what was observed after i.v. administration of the unformulated [(3)H]-SSB siRNA, where no intact parent guide strand could be observed 5 minutes post dosing. The disposition of the siRNA was determined by the pharmacokinetics of the formulated LNP vehicle itself. In this study, the radioactivity was widely distributed throughout the body, and the total radioactivity concentration was determined in selected tissues. The highest concentrations of radioactivity were found in the spleen, liver, esophagus, stomach, adrenal, and seminal vesicle wall. In conclusion, the LNP vehicle was found to drive the kinetics and biodistribution of the SSB siRNA. The renal clearance was significantly reduced and its exposure in plasma significantly increased compared with the unformulated [(3)H]-SSB siRNA.
authors.affiliation: Drug Metabolism and Pharmacokinetics (J.C., K.L., T.F., E.v.d.K., O.H., J.K., P.S.), Analytical Sciences (M.S.), and Biologics Center (F.N., J.H., J.Bo., I.B.), Novartis Pharma AG, Novartis Institutes for Biomedical Research, Basel, Switzerland; and Biologics Center, Novartis Pharma AG, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts (K.B., J.B., M.B., C.V.).
authors.forename: Jesper
authors.initials: J
authors.lastname: Christensen
authors.forename: Karine
authors.initials: K
authors.lastname: Litherland
authors.forename: Thomas
authors.initials: T
authors.lastname: Faller
authors.forename: Esther
authors.initials: E
authors.lastname: van de Kerkhof
authors.forename: François
authors.initials: F
authors.lastname: Natt
authors.forename: Jürg
authors.initials: J
authors.lastname: Hunziker
authors.forename: Julien
authors.initials: J
authors.lastname: Boos
authors.forename: Iwan
authors.initials: I
authors.lastname: Beuvink
authors.forename: Keith
authors.initials: K
authors.lastname: Bowman
authors.forename: Jeremy
authors.initials: J
authors.lastname: Baryza
authors.forename: Mike
authors.initials: M
authors.lastname: Beverly
authors.forename: Chandra
authors.initials: C
authors.lastname: Vargeese
authors.forename: Olivier
authors.initials: O
authors.lastname: Heudi
authors.forename: Markus
authors.initials: M
authors.lastname: Stoeckli
authors.forename: Joel
authors.initials: J
authors.lastname: Krauser
authors.forename: Piet
authors.initials: P
authors.lastname: Swart
mesh_terms: D000818:Animals; D001345:Autoradiography; D002851:Chromatography, High Pressure Liquid; D004337:Drug Carriers / Q000737:chemistry / Q000378:metabolism* / Q000493:pharmacokinetics; D004355:Drug Stability; D007275:Injections, Intravenous; D008055:Lipids / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D053758:Nanoparticles / Q000737:chemistry / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000097:blood / Q000737:chemistry / Q000378:metabolism* / Q000493:pharmacokinetics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014018:Tissue Distribution; D014316:Tritium; D014915:Whole-Body Counting
chemical_list: D004337:Drug Carriers; D008055:Lipids; D034741:RNA, Small Interfering; D014316:Tritium