Effect of trastuzumab on the micellization properties, endocytic pathways and antitumor activities of polyurethane-based drug delivery system

Molecular bottlebrush with pH-responsive cleavable bonds as a unimolecular vehicle for anticancer drug delivery

Drug delivery systems with targeted and smart properties have emerged as an efficient strategy to overcome the challenges of cancer chemotherapy such as toxic side effects and the development of multidrug resistance. In this study, a biocompatible bottlebrush polymer poly((3-(2-bromo-2-methylpropionate)propyldimethylsilyloxy)ethyl methacrylate)-graft-poly(2-methacryloyloxyethyl phosphorylcholine) P(BIBS-EMA)-g-PMPC with pH-responsive silanol cleavable bond was designed and developed for delivery of doxorubicin. A549 cell line of human lung carcinoma was tested. The synthesized bottlebrush polymer was analyzed and characterized via Fourier transform infrared spectroscopy, FTIR, nuclear magnetic resonance spectroscopy, ¹H NMR, gel permeation chromatography, GPC, dynamic laser light scattering, DLS, and static laser light scattering, SLS, techniques. The cleavage process was also precisely studied to confirm the pH-responsiveness of such bottlebrush polymers. In vitro loading and release studies of doxorubicin as a model drug were examined and the results showed a pH-dependent release manner with a twice higher release rate under cancerous tissue conditions compared to standard physiological conditions. MTT cytotoxicity assay was also performed to prove the biocompatibility of the designed polymeric platform on healthy human cells. Due to the presence of bio-inspired poly(2-methacryloyloxyethyl phosphorylcholine) side chains in the prepared bottlebrush polymer, the formed polymer-drug complex could also exhibit effective internalization into tumor cells. These facts further support the potential use of this carrier in drug delivery applications and for further in vivo studies.

Solid Polymeric Nanoparticles of Albendazole: Synthesis, Physico-Chemical Characterization and Biological Activity

Albendazole is a benzimidazole derivative with documented antitumor activity and low toxicity to healthy cells. The major disadvantage in terms of clinical use is its low aqueous solubility which limits its bioavailability. Albendazole was incorporated into stable and homogeneous polyurethane structures with the aim of obtaining an improved drug delivery system model. Spectral and thermal analysis was used to investigate the encapsulation process and confirmed the presence of albendazole inside the nanoparticles. The in vitro anticancer properties of albendazole encapsulated in polyurethane structures versus the un-encapsulated compound were tested on two breast cancer cell lines, MCF-7 and MDA-MB-231, in terms of cellular viability and apoptosis induction. The study showed that the encapsulation process enhanced the antitumor activity of albendazole on the MCF-7 and MDA-MB-23 breast cancer lines. The cytotoxic activity manifested in a concentration-dependent manner and was accompanied by changes in cell morphology and nuclear fragmentation.

Stable, Bioresponsive, and Macrophage-Evading Polyurethane Micelles Containing an Anionic Tripeptide Chain Extender

Polymeric nanocarriers have been extensively used in medicinal applications for drug delivery. However, intravenous nanocarriers circulating in the blood will be rapidly cleared from the mononuclear macrophage system. The surface physicochemical characterizations of nanocarriers are the primary factors to determine their fate in vivo, such as evading the reticuloendothelial system, exhibiting long blood circulation times, and accumulating in the targeted site. In this work, we develop a series of polyurethane micelles containing segments of an anionic tripeptide, hydrophilic mPEG, and disulfide bonds. It is found that the long hydrophilic mPEG can shield the micellar surface and have a synergistic effect with the negatively charged tripeptide to minimize macrophage phagocytosis. Meanwhile, the disulfide bond can rapidly respond to the intracellular reduction environment, leading to the acceleration of drug release and improvement of the therapeutic effect. Our results verify that these anionic polyurethane micelles hold great potential in the development of the stealth immune system and controllable intracellular drug transporters.

Facile Preparation of Reduction-Responsive Micelles Based on Biodegradable Amphiphilic Polyurethane with Disulfide Bonds in the Backbone

In this paper, we synthesized a biodegradable amphiphilic polymer of polyurethane-polyethylene glycol with disulfide bonds in the main chain (PEG-PU(SS)-PEG). DLS and SEM showed that the polymer could self-assemble into micelles in aqueous solution and could be used to load the hydrophobic anticancer drug DOX. Intriguingly, drug release in vitro indicated that DOX-loaded PEG-PU(SS)-PEG micelles had good stability under the extracellular physiological environment, but the disulfide bonds broke rapidly and DOX was released quickly under the intracellular reducing conditions. CCK-8 assays showed that DOX-loaded PEG-PU(SS)-PEG micelles had a high in vitro antitumor activity in C6 cells, whereas blank PEG-PU(SS)-PEG micelles were nontoxic to C6 cells. It was also found that there was strong and persistent accumulation of DOX-loaded PEG-PU(SS)-PEG as compared with PEG-PU-PEG both by the cell internalization tests and the flow cytometry measurements. Hence, PEG-PU(SS)-PEG micelles will have a potential use for clinical treatment of cancer in the future.