On the Importance of Polyurethane and Polyurea Nanosystems for Future Drug Delivery

BACKGROUND

During the last decade, polyurethanes and polyureas have emerged as promising alternatives to classical polyacrylate-, polyester- and polyaminoacid-based drug delivery nanosystems. They are not only biocompatible and biodegradable, but also facilitate the manufacture of polymeric nanostructured nanoparticles in quantitative yields. The versatile chemistry reduces the amount of organic solvents used and allows the straightforward multifunctionalization of polymer precursors with the desired targeting molecule at each stage of the process.

OBJECTIVES

To highlight the common issues encountered in current drug delivery systems (DDSs) and the state of the art of polyurethane and polyurea polymers that self-assemble in a stratified manner by hydrophobic interactions. Finally, we discuss the importance of taking a holistic view when applying polymer nanotechnologies, in order to enhance their efficiency during preclinical and clinical studies.

CONCLUSIONS

Polyurethane-polyurea nanoparticles (PUUa NPs) emerge as suitable platforms to be manufactured in a cost-effective manner at industrial scale and following environmentally friendly synthetic methods. Furthermore, they allow the controlled delivery of a wide range of drugs and can be rapidly adapted to many clinical requirements by means of FDA-approved precursors. Additionally, the ease with which PUUa nanoparticles are biodegraded ensures control over temporal aspects of drug delivery compared to other nanosystems. These advantages make PUUa NPs attractive drug delivery vehicles as long as adequate safety and ethical guidelines for new NP formulations are developed.

Improved pharmacokinetic profile of lipophilic anti-cancer drugs using ανβ3-targeted polyurethane-polyurea nanoparticles

Glutathione degradable polyurethane-polyurea nanoparticles (PUUa NP) with a disulfide-rich multiwalled structure and a cyclic RGD peptide as a targeting moiety were synthesized, incorporating a very lipophilic chemotherapeutic drug named Plitidepsin. In vitro studies indicated that encapsulated drug maintained and even improved its cytotoxic activity while in vivo toxicity studies revealed that the maximum tolerated dose (MTD) of Plitidepsin could be increased three-fold after encapsulation. We also found that pharmacokinetic parameters such as maximum concentration (Cmax), area under the curve (AUC) and plasma half-life were significantly improved for Plitidepsin loaded in PUUa NP. Moreover, biodistribution assays in mice showed that RGD-decorated PUUa NP accumulate less in spleen and liver than non-targeted conjugates, suggesting that RGD-decorated nanoparticles avoid sequestration by macrophages from the reticuloendothelial system. Overall, our results indicate that polyurethane-polyurea nanoparticles represent a very valuable nanoplatform for the delivery of lipophilic drugs by improving their toxicological, pharmacokinetic and whole-body biodistribution profiles.

Nanoencapsulated budesonide in self-stratified polyurethane-polyurea nanoparticles is highly effective in inducing human tolerogenic dendritic cells

The design of innovative strategies to selectively target cells, such antigen-presenting cells and dendritic cells, in vivo to induce immune tolerance is gaining interest and relevance for the treatment of immune-mediated diseases. A novel loaded-nanosystem strategy to generate tolerogenic dendritic cells (tol-DCs) was evaluated. Hence budesonide (BDS) was encapsulated in multiwalled polyurethane-polyurea nanoparticles (PUUa NPs-BDS) based on self-stratified polymers by hydrophobic interactions at the oil-water interface. DCs treated with encapsulated BDS presented a prominent downregulation of costimulatory molecules (CD80, CD83 and MHCII) and upregulation of inhibitory receptors. Moreover, DCs treated with these PUUa NPs-BDS also secreted large amounts of IL-10, a crucial anti-inflammatory cytokine to induce tolerance, and inhibited T lymphocyte activation in a specific manner compared to those cells generated with free BDS. These results demonstrate that PUUa NPs-BDS are a highly specific and efficient system through which to induce DCs with a tolerogenic profile. Given the capacity of PUUa NPs-BDS, this delivery system has a clear advantage for translation to in vivo studies.

Multisensitive drug-loaded polyurethane/polyurea nanocapsules with pH-synchronized shell cationization and redox-triggered release

A one-pot versatile method for the preparation of sub-30 nm multisensitive polyurethane/polyurea nanocapsules with pH-synchronized shell cationization is presented. The nanocapsules have been loaded with different drugs which are released through a redox-triggered mechanism.

Correction: Multifunctionalized polyurethane-polyurea nanoparticles: hydrophobically driven self-stratification at the o/w interface modulates encapsulation stability

Correction for 'Multifunctionalized polyurethane-polyurea nanoparticles: hydrophobically driven self-stratification at the o/w interface modulates encapsulation stability' by Pau Rocas et al., J. Mater. Chem. B, 2015, DOI: .

Installing multifunctionality on titanium with RGD-decorated polyurethane-polyurea roxithromycin loaded nanoparticles: toward new osseointegrative therapies

A novel class of polyurethane-polyurea nanoparticles (PUUa NPs) to install multifunctionality on biomaterials is presented. Biofunctionalization of titanium with roxithromycin loaded RGD-decorated PUUa NPs results in an outstanding improvement of osteoblast adhesion and strong suppression of bacterial attachment. This strategy represents a powerful approach to enhance the osseointegration of implant materials.

Multifunctionalized polyurethane-polyurea nanoparticles: hydrophobically driven self-stratification at the o/w interface modulates encapsulation stability

Polyurethane-polyurea (PUUa) reactive prepolymers with adjusted hydrophobic and hydrophilic dangling chains to achieve multiwalled sub-30 nm nanoparticles are presented. The combination of an amphiphilic and a hydrophobic prepolymer at the oil-water interface creates a stratified shell by hydrophobic interactions. These novel nanostructures enhance the encapsulation stability of lipophilic compounds compared to monowalled nanostructures and facilitate the selective and ordered functionalization along the multiwalled shell with bioactive motifs. As proof of concept, PUUa nanoparticles have been engineered with disulfide bonds and an α_vβ₃ integrin-selective cyclic RGD peptide (cRGDfK) providing our system with glutathione (GSH) triggered controlled release and cell targeting specificity to U87 tumor cells.

[Acute hepatitis caused by cyclofenil (Ondogyne). Apropos of 2 cases]

We report the cases of two adults suffering from acute hepatitis due to cyclofenil (Ondogyne), a drug proposed for the treatment of dysovulation and scleroderma. Hepatitis developed 30 and 102 days after the beginning of discontinuous administration of the drug. A challenge test was positive in both cases. The course of hepatitis was reversible after withdrawal of the drug. Hepatitis induced by cyclofenil is likely to be due to an hypersensitivity mechanism.