Abstract
Abstract Methotrexate (MTX) anticancer drug was successfully loaded and released in a controlled manner from polymer micelles made of a diblock copolymer of poly(monomethoxy ethylene glycol)-b-poly(ε-caprolactone) (mPEG-PCL). The empty and MTX-loaded micelles (MTX/mPEG-PCL) were characterized by electron microscopy. The drug release dependence upon pH 5.4, 6.5, and 7.4 for 30 days was proven and characterized by UV-Vis spectroscopy. The cytotoxic effect of MTX/mPEG-PCL micelles on MCF-7 breast cancer cells was evaluated through an MTT assay. The morphological analysis indicated the successful formation of micelles of 76 and 131 nm for empty and MTX-loaded micelles, respectively. An encapsulation efficiency of 70.2% and a loading capacity of 8.8% were obtained. The in vitro release of MTX showed a gradual and sustained profile over 22 days, with a clear trend to much higher release at acidic pH (80 and 90% for pH 6.7 and 5.5, respectively). The MTX/mPEG-PCL micelles showed an IC50 of MCF-7 cells at 30 µg mL−1. The results suggested that MTX/mPEG-PCL could be a promising drug delivery system for cancer treatment.
Highlights
Methotrexate (MTX) anticancer drug was successfully loaded and released in a controlled manner from polymer micelles made of a diblock copolymer of poly(monomethoxy ethylene glycol)-b-poly(ε-caprolactone)
To determine the influence of a simulated pH for tumor microenvironments or lysosomes on the behavior of MTX/poly(ethylene glycol)-b-poly(ε-caprolactone) (PEG-PCL) micelles, MTX release experiments were achieved in phosphate-buffered saline (PBS) solutions at pH 6.7 and 5.5. pH 7.4 was assayed to determine the behavior under normal physiological conditions (Figure 8)
The maximum MTX release at pH 7.4 was around 10% in 30 days, whereas at pH 6.7 a release of 15% was recorded within the first 2 days, followed by a gradual increase, achieving a maximum of 80% of drug release hydrophilicity and, improves water solubility [52]. This high solubility of PEG has been observed in most organic and inorganic solvents [53]. Taking these observations into consideration, it can be suggested that the release pattern presented by the mPEG-PCL micelles is caused by the hydrophilic moiety of the copolymer, which is solubilized in an acidic environment, causing a gradual drug release as it is dissolved
Summary
Abstract: Methotrexate (MTX) anticancer drug was successfully loaded and released in a controlled manner from polymer micelles made of a diblock copolymer of poly(monomethoxy ethylene glycol)-b-poly(ε-caprolactone) (mPEG-PCL). Diblock copolymer micelles of poly(ethylene glycol)-b-poly(ε-caprolactone) (PEG-PCL) (Figure 1a) have received attention for loading therapeutic drugs [3,4]. Because of their amphiphilic character, diblock copolymers form micellar systems that can interact with hydrophilic or hydrophobic compounds such as anti-cancer drugs. This work is licensed under the Creative Commons pH-responsive copolymer micelles for MTX delivery 625 poly(monomethoxy ethylene glycol)-b-poly(ε-caprolactone) (mPEG-PCL) micelles, with an average diameter of 72 nm, the release of MTX was reported as dependent on the pH, with higher release at acidic pH than in the neutral environment. The characterization of empty micelles and loaded micelles with MTX is presented, as well as their cytotoxic effect toward MCF-7 breast cancer cells compared to free MTX to assess their potential as a treatment against breast cancer
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