title: Pharmacokinetic and biodistribution studies of a bone-targeting drug delivery system based on N-(2-hydroxypropyl)methacrylamide copolymers.
abstract: Osteotropicity of novel bone-targeted HPMA copolymer conjugates has been demonstrated previously with bone histomorphometric analysis. The pharmacokinetics and biodistribution of this delivery system were investigated in the current study with healthy young BALB/c mice. The 125I-labeled bone-targeted and control (nontargeted) HPMA copolymers were administered intravenously to mice, and their distribution to different organs and tissues was followed using gamma counter and single photon emission computed tomography (SPECT). Both the invasive and noninvasive data further confirmed that the incorporation of D-aspartic acid octapeptide (D-Asp8) as bone-targeting moiety could favorably deposit the HPMA copolymers to the entire skeleton, especially to the high bone turnover sites. To evaluate the influence of molecular weight, three fractions (Mw of 24, 46, and 96 kDa) of HPMA copolymer-D-Asp8 conjugate were prepared and evaluated. Higher molecular weight of the conjugate enhanced the deposition to bone due to the prolonged half-life in circulation, but it weakened the bone selectivity. A higher content of bone-targeting moiety (D-Asp8) in the conjugate is desirable to achieve superior hard tissue selectivity. Further validation of the bone-targeting efficacy of the conjugates in animal models of osteoporosis and other skeletal diseases is needed in the future.
authors.affiliation: Department of Pharmaceutics and Pharmaceutical Chemistry/CCCD, University of Utah, Salt Lake City, Utah 84112, USA.
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.forename: Monika
authors.initials: M
authors.lastname: Sima
authors.forename: R Lee
authors.initials: RL
authors.lastname: Mosley
authors.forename: Jasmine P
authors.initials: JP
authors.lastname: Davda
authors.forename: Nicole
authors.initials: N
authors.lastname: Tietze
authors.forename: Scott C
authors.initials: SC
authors.lastname: Miller
authors.forename: Peter R
authors.initials: PR
authors.lastname: Gwilt
authors.forename: Pavla
authors.initials: P
authors.lastname: Kopecková
authors.forename: Jindrich
authors.initials: J
authors.lastname: Kopecek
mesh_terms: D000818:Animals; D001224:Aspartic Acid / Q000737:chemistry; D001682:Biological Availability; D050071:Bone Density Conservation Agents / Q000008:administration & dosage* / Q000138:chemical synthesis / Q000493:pharmacokinetics*; D001842:Bone and Bones / Q000187:drug effects*; D016503:Drug Delivery Systems / Q000379:methods*; D051379:Mice; D008807:Mice, Inbred BALB C; D008954:Models, Biological; D011108:Polymers / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000493:pharmacokinetics*; D014018:Tissue Distribution; D014443:Tyrosine / Q000737:chemistry
chemical_list: D050071:Bone Density Conservation Agents; D011108:Polymers; D011109:Polymethacrylic Acids; D001224:Aspartic Acid; C011533:Duxon; D014443:Tyrosine