1. Academic Validation
  2. Feasibility of poly(ethylene glycol) derivatives as diagnostic drug carriers for tumor imaging

Feasibility of poly(ethylene glycol) derivatives as diagnostic drug carriers for tumor imaging

  • J Control Release. 2016 Mar 28;226:115-23. doi: 10.1016/j.jconrel.2016.02.017.
Kengo Kanazaki 1 Kohei Sano 2 Akira Makino 3 Fumio Yamauchi 4 Atsushi Takahashi 4 Tsutomu Homma 4 Masahiro Ono 5 Hideo Saji 6
Affiliations

Affiliations

  • 1 Department of Patho-Functional Bioanalysis Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto, 606-8501, Japan; Medical Imaging Project, Corporate R&D Headquarters, Canon Inc., 3-30-2 Shimomaruko, Ohta-ku, Tokyo, 146-8501, Japan.
  • 2 Department of Patho-Functional Bioanalysis Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto, 606-8501, Japan; Kyoto University Hospital, 54 Kawaharacho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan.
  • 3 Department of Patho-Functional Bioanalysis Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto, 606-8501, Japan; Biomedical Imaging Research Center, University of Fukui, 23-3 Matsuokashimoaizuki, Eiheiji-cho, Yoshida-gun, Fukui, 910-1193, Japan.
  • 4 Medical Imaging Project, Corporate R&D Headquarters, Canon Inc., 3-30-2 Shimomaruko, Ohta-ku, Tokyo, 146-8501, Japan.
  • 5 Department of Patho-Functional Bioanalysis Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto, 606-8501, Japan.
  • 6 Department of Patho-Functional Bioanalysis Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto, 606-8501, Japan. Electronic address: hsaji@pharm.kyoto-u.ac.jp.
Abstract

Poly(ethylene glycol) (PEG) is an artificial but biocompatible hydrophilic polymer that has been widely used in clinical products. To evaluate the feasibility of using PEG derivative itself as a tumor imaging carrier via an enhanced permeability and retention (EPR) effect, we prepared indium-111-labeled PEG ((111)In-DTPA-PEG) and indocyanine green (ICG)-labeled PEG (ICG-PEG) with PEG molecular weights of 5-40kDa and investigated their in vivo biodistribution in colon26 tumor-bearing mice. Thereafter, single-photon emission computed tomography (SPECT) and photoacoustic (PA) imaging studies were performed. The in vivo biodistribution studies demonstrated increased tumor uptake and a prolongation of circulation half-life as the molecular weight of PEG increased. Although the observed differences in in vivo biodistribution were dependent on the labeling method ((111)In or ICG), the tumor-to-normal tissue ratios were comparable. Because PEG-based probes with a molecular weight of 20kDa (PEG20) showed a preferable biodistribution (highest accumulation among tissues excised and relatively high tumor-to-blood ratios), an imaging study using (111)In-DTPA-PEG20 and ICG-PEG20 was performed. Colon26 tumors inoculated in the right shoulder were clearly visualized by SPECT 24h after administration. Furthermore, PA imaging using ICG-PEG20 also detected tumor regions, and the detected PA signals increased in proportion with the injected dose. These results suggest that PEG derivatives (20kDa) serve as robust diagnostic drug carriers for tumor imaging.

Keywords

Cancer diagnosis; Indocyanine green; Photoacoustic imaging; Poly(ethylene glycol); Single-photon emission computed tomography.

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