Cyclodextrin-Based Polymeric Drug Delivery Systems for Cancer Therapy

Abstract

Cyclodextrins (CDs) are one of the most extensively studied cyclic-oligosaccharides due to their low toxicity, good biodegradability and biocompatibility, facile chemical modification, and unique inclusion capacity. However, problems such as poor pharmacokinetics, plasma membrane disruption, hemolytic effects and a lack of target specificity still exist for their applications as drug carriers. Recently, polymers have been introduced into CDs to combine the advantages of both biomaterials for the superior delivery of anticancer agents in cancer treatment. In this review, we summarize four types of CD-based polymeric carriers for the delivery of chemotherapeutics or gene agents for cancer therapy. These CD-based polymers were classified based on their structural properties. Most of the CD-based polymers were amphiphilic with the introduction of hydrophobic/hydrophilic segments and were able to form nanoassemblies. Anticancer drugs could be included in the cavity of CDs, encapsulated in the nanoparticles or conjugated on the CD-based polymers. In addition, the unique structures of CDs enable the functionalization of targeting agents and stimuli-responsive materials to realize the targeting and precise release of anticancer agents. In summary, CD-based polymers are attractive carriers for anticancer agents.

Keywords: conjugate; copolymer; crosslink; cyclodextrin; polymer; polyrotaxane.

Figure 1

Chemical structure of α-CD, β-CD and γ-CD.

Figure 2

Schematic illustration of polyrotaxane.

Figure 3

Chemical structure of NLG 207 (CRLX 101).

Figure 4

Schematic illustration of star-shaped copolymers (a), polymers with pendant CD (b) and polymers with pendant guest components (c).

Figure 5

Chemical structure of PDMEMA (a) and PDPA (b).

Figure 6

Chemical structure of β-CD-OEI-HA.

Figure 7

Schematic illustration of EPI-crosslinked γ-CD polymer complexed with AdRGD and Dox.