Poly(caprolactone)- b-poly(ethylene glycol)-Based Polymeric Micelles as Drug Carriers for Efficient Breast Cancer Therapy: A Systematic Review

Abstract

Recently, drug delivery systems based on nanoparticles for cancer treatment have become the centre of attention for researchers to design and fabricate drug carriers for anti-cancer drugs due to the lack of tumour-targeting activity in conventional pharmaceuticals. Poly(caprolactone)-b-poly(ethylene glycol) (PCL-PEG)-based micelles have attracted significant attention as a potential drug carrier intended for human use. Since their first discovery, the Food and Drug Administration (FDA)-approved polymers have been studied extensively for various biomedical applications, specifically cancer therapy. The application of PCL-PEG micelles in different cancer therapies has been recorded in countless research studies for their efficacy as drug cargos. However, systematic studies on the effectiveness of PCL-PEG micelles of specific cancers for pharmaceutical applications are still lacking. As breast cancer is reported as the most prevalent cancer worldwide, we aim to systematically review all available literature that has published research findings on the PCL-PEG-based micelles as drug cargo for therapy. We further discussed the preparation method and the anti-tumour efficacy of the micelles. Using a prearranged search string, Scopus and Science Direct were selected as the databases for the systematic searching strategy. Only eight of the 314 articles met the inclusion requirements and were used for data synthesis. From the review, all studies reported the efficiency of PCL-PEG-based micelles, which act as drug cargo for breast cancer therapy.

Keywords: PCL-PEG; breast cancer; drug cargo; drug delivery; polymer micelle.

Figure 1

The flow diagram of the systematic literature review (adapted from Mohamed Shaffril et al. [31]).

Figure 2

Schematic route for the preparation of PCL-PEG copolymers.

Figure 3

Preparation of (A) FA-L-PEG-OH and (B) FA-L-PEG-PCL. Reprinted/adapted with permission from Elsevier [40].

Figure 4

DSC thermogram of (a) CUR (b) mPEG-PCL, and (c) CUR/mPEG-PCL micelles. Reprinted/adapted with permission from Elsevier [35].

Figure 5

The formulation strategy of (a) Blank micelles, (b) PTX/CL-PEG, and (c) PTX/PCL-PEG-Herceptin. Reprinted/adapted with permission from Elsevier [42].

Figure 6

DSC curves of copolymers and drug-loaded copolymers. Reprinted/adapted with permission from Elsevier [40].

Figure 7

The release profile of CUR from CUR/MPEG-PCL micelles in different release media. Reprinted/adapted with permission from Elsevier [35].

Figure 8

In vitro cell cytotoxicity of free CBZ and CBZ-loaded block copolymer micelles against MCF-7 and MDA-MB 231 after a 72 h incubation. Reprinted/adapted with permission from Elsevier [38].