UNCORRECTED PROOF IJP 8239 1–10 International Journal of Pharmaceutics xxx (2005) xxx–xxx Pharmacokinetics and biodistribution of RGD-targeted doxorubicin-loaded nanoparticles in tumor-bearing mice 3 4 David C. Bibby a, ∗ , James E. Talmadge b , Milind K. Dalal a , Scott G. Kurz b , Kevin M. Chytil b , Stephen E. Barry a , David G. Shand a , Matthias Steiert a 5 6 a Alnis BioSciences Inc., 5764 Shellmound St., Emeryville, CA 94608, USA 7 b University of Nebraska Medical Center, Omaha, NE 68198, USA 8 Received 21 September 2004; received in revised form 22 December 2004; accepted 22 December 2004 9 Abstract 10 We report the biodistribution and pharmacokinetics (PK) of a cyclic RGD-doxorubicin-nanoparticle (NP) formulation in tumor-bearing mice. The NP core was composed of inulin multi-methacrylate with a targeting peptide, cyclic RGD, covalently attached to the NPs via PEG-400. Seventy-two percent of the doxorubicin was attached to the NP matrix via an amide bond; 28% of doxorubicin was entrapped as unconjugated drug. The PK of total, unconjugated and metabolized doxorubicin was examined for 5 days following intravenous (i.v.) administration of the NP formulation (250 g doxorubicin equiv.), revealing a bi-exponential fix with a terminal half-life of 5.99 h. In addition, the biodistribution studies revealed decreasing drug concentrations over time in the heart, lung, kidney and plasma and accumulating drug concentrations in the liver, spleen and tumor. The drug concentration in these latter tissues peaked between 24 and 48 h with the liver, spleen and tumor containing 56, 3.5 and 1.8% of the administered dose at t = 48 h, respectively. In contrast to all of the organs studied, the tumors contained high levels of a doxorubicin metabolite. 11 12 13 14 15 16 17 18 19 © 2005 Published by Elsevier B.V. 20 Keywords: Pharmacokinetics; Biodistribution; Nanoparticles; Doxorubicin; Mice 21 22 Abbreviations: CiBA, cystine bisacrylamide; Cl-66, mam- mary tumor clone-66; IMMA, inulin multi-methacrylate; I.S., in- ternal standard; LOD, limit of detection; NaA, sodium acrylate; NP, nanoparticles; PEG 400 DBA, poly(ethylene glycol) 400- dibromoacetate. ∗ Corresponding author. Tel.: +1 510 420 3760; fax: +1 510 420 3761. E-mail address: alnis@alnis.com (D.C. Bibby). 1. Introduction 1 Doxorubicin is an anthracycline, widely used in the 2 treatment of breast and ovarian cancer (Devita et al., 3 1989; Martindale, 1996; Vermorken, 2003). However, 4 dose-limiting toxicities occur with doxorubicin ther- 5 apy and include myelosuppression and cardiotoxicity. 6 Congestive heart failure is of particular concern, and is 7 dosage cumulative such that no more than 550 mg/m 2 8 is recommended as a lifetime total dose (Von Hoff et al., 9 1 0378-5173/$ – see front matter © 2005 Published by Elsevier B.V. 2 doi:10.1016/j.ijpharm.2004.12.021