Doxorubicin-Loaded Delta Inulin Conjugates for Controlled and Targeted Drug Delivery: Development, Characterization, and In Vitro Evaluation

Lixin Wang; Yunmei Song; Ankit Parikh; Paul Joyce; Rosa Chung; Liang Liu; Franklin Afinjuomo; John D Hayball; Nikolai Petrovsky; Thomas G Barclay; Sanjay Garg

doi:10.3390/pharmaceutics11110581

Doxorubicin-Loaded Delta Inulin Conjugates for Controlled and Targeted Drug Delivery: Development, Characterization, and In Vitro Evaluation

Pharmaceutics. 2019 Nov 6;11(11):581. doi: 10.3390/pharmaceutics11110581.

Authors

Lixin Wang¹, Yunmei Song¹, Ankit Parikh¹, Paul Joyce², Rosa Chung¹, Liang Liu³, Franklin Afinjuomo¹, John D Hayball^{3

4}, Nikolai Petrovsky^{5

6}, Thomas G Barclay¹, Sanjay Garg¹

Affiliations

¹ Centre for Pharmaceutical Innovation and Development, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide SA 5000, Australia.
² Division of Biological Physics, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
³ Experimental Therapeutics Laboratory, University of South Australia Cancer Research Institute, Adelaide SA 5000, Australia.
⁴ Robinson Research Institute and Adelaide Medical School, University of Adelaide, Adelaide SA 5005, Australia.
⁵ Vaxine Pty Ltd., Bedford Park, Adelaide 5042, Australia.
⁶ Department of Diabetes and Endocrinology, Flinders University, Adelaide 5042, Australia.

Abstract

Delta inulin, also known as microparticulate inulin (MPI), was modified by covalently attaching doxorubicin to its nanostructured surface for use as a targeted drug delivery vehicle. MPI is readily endocytosed by monocytes, macrophages, and dendritic cells and in this study, we sought to utilize this property to develop a system to target anti-cancer drugs to lymphoid organs. We investigated, therefore, whether MPI could be used as a vehicle to deliver doxorubicin selectively, thereby reducing the toxicity of this antibiotic anthracycline drug. Doxorubicin was covalently attached to the surface of MPI using an acid-labile linkage to enable pH-controlled release. The MPI-doxorubicin conjugate was characterized using FTIR and SEM, confirming covalent attachment and indicating doxorubicin coupling had no obvious impact on the physical nanostructure, integrity, and cellular uptake of the MPI particles. To simulate the stability of the MPI-doxorubicin in vivo, it was stored in artificial lysosomal fluid (ALF, pH 4.5). Although the MPI-doxorubicin particles were still visible after 165 days in ALF, 53% of glycosidic bonds in the inulin particles were hydrolyzed within 12 days in ALF, reflected by the release of free glucose into solution. By contrast, the fructosidic bonds were much more stable. Drug release studies of the MPI-doxorubicin in vitro, demonstrated a successful pH-dependent controlled release effect. Confocal laser scanning microscopy studies and flow cytometric analysis confirmed that when incubated with live cells, MPI-doxorubicin was efficiently internalized by immune cells. An assay of cell metabolic activity demonstrated that the MPI carrier alone had no toxic effects on RAW 264.7 murine monocyte/macrophage-like cells, but exhibited anti-cancer effects against HCT116 human colon cancer cells. MPI-doxorubicin had a greater anti-cancer cell effect than free doxorubicin, particularly when at lower concentrations, suggesting a drug-sparing effect. This study establishes that MPI can be successfully modified with doxorubicin for chemotherapeutic drug delivery.

Keywords: advax; anticancer therapy; doxorubicin; intracellular drug release; inulin; pH sensitive; targeted delivery.

Abstract

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