Two novel nanoscale preparations of micelle and thermosensitive hydrogel for docetaxel to treat malignant tumor

Understanding and Regulating Cell-Matrix Interactions Using Hydrogels of Designable Mechanical Properties

Similar to natural tissues, hydrogels contain abundant water, so they are considered as promising biomaterials for studying the influence of the mechanical properties of extracellular matrices (ECM) on various cell functions. In recent years, the growing research on cellular mechanical response has revealed that many cell functions, including cell spreading, migration, tumorigenesis and differentiation, are related to the mechanical properties of ECM. Therefore, how cells sense and respond to the extracellular mechanical environment has gained considerable attention. In these studies, hydrogels are widely used as the in vitro model system. Hydrogels of tunable stiffness, viscoelasticity, degradability, plasticity, and dynamical properties have been engineered to reveal how cells respond to specific mechanical features. In this review, we summarize recent process in this research direction and specifically focus on the influence of the mechanical properties of the ECM on cell functions, how cells sense and respond to the extracellular mechanical environment, and approaches to adjusting the stiffness of hydrogels.

Injectable Hydrogels Coencapsulating Granulocyte-Macrophage Colony-Stimulating Factor and Ovalbumin Nanoparticles to Enhance Antigen Uptake Efficiency

The combination of an antigen and adjuvant has synergistic effects on an immune response. Coadministration of an antigen and a granulocyte-macrophage colony-stimulating factor (GM-CSF) hydrogel delivery system will afford a novel strategy for enhancement of an immune response because of the dual role of the hydrogel as a vaccine carrier with a sustained release and a platform for recruiting dendritic cells (DCs). Herein, an injectable poly(caprolactone)-poly(ethylene glycol)-poly(caprolactone) thermosensitive hydrogel coencapsulating GM-CSF and ovalbumin nanoparticles was developed to enhance antigen uptake efficiency. The GM-CSF released from the hydrogel ensured accumulation of DCs; this effect improved the antigen uptake efficiency with the targeted delivery to antigen-presenting cells. Furthermore, the dual delivery system induced a stronger immune effect, including higher CD8⁺ T proportion, interferon γ secretion, and a greater cytotoxic T lymphocyte response, which may benefit from the recruitment of DCs, increasing antigen residence time, and the controllable antigen release owing to the combined effect of the hydrogel and nanoparticles. Meanwhile, the real-time antigen delivery process in vivo was revealed by a noninvasive fluorescence imaging method. All of the results indicated that the visible dual delivery system may have a greater potential for the efficient and trackable vaccine delivery.

Sustained drug release and cancer treatment by an injectable and biodegradable cyanoacrylate-based local drug delivery system

Sustained drug release at specific sites is clinically favorable for the treatment of many diseases. The discovery of new polymeric materials suitable for prolonging drug release, improving therapeutic efficiency, and decreasing systemic toxicity is always of great interest in local sustained-release drug delivery systems (LSRDDSs). In this study, a new cross-linked cyanoacrylate (CA)-based LSRDDS is developed, in which the drug depot consists of a formulation of methoxyethyl cyanoacrylate (MOE-CA) with the cross-linking agent CA-PEG-CA. The MOE-CA endowed the CA polymer with good degradability. The drug-release profile could be affected by the structure and composition ratio of the MOE-CA/CA-PEG-CA monomer. The liquid CA monomer could dissolve the drug without using other solvents, and could polymerize into a solid glue just in a few seconds after injection. An optimal formulation loaded with 5-fluorouracil (J-Fu-1.25) showed excellent anticancer activity both in vitro and in vivo, with 50% survival of the mice and no significant systemic toxicity detected during the experiment. The CA depot might affect the blood flow in microvessels of tumors, thus contributing to the synergetic anticancer effect of 5-fluorouracil. We believe that this work provides a practical, biodegradable, and biocompatible LSRDDS for chemotherapeutic drug delivery that can also be applied universally with various drugs for certain therapeutic aims.

Combination antitumor therapy with targeted dual-nanomedicines

Combination therapy is one of the important treatment strategies for cancer at present. However, the outcome of current combination therapy based on the co-administration of conventional dosage forms is suboptimal, due to the short half-lives of chemodrugs, their deficient tumor selectivity and so forth. Nanotechnology-based targeted delivery systems show great promise in addressing the associated problems and providing superior therapeutic benefits. In this review, we focus on the combination of therapeutic strategies between different nanomedicines or drug-loaded nanocarriers, rather than the co-delivery of different drugs via a single nanocarrier. We introduce the general concept of various targeting strategies of nanomedicines, present the principles of combination antitumor therapy with dual-nanomedicines, analyze their advantages and limitations compared with co-delivery strategies, and overview the recent advances of combination therapy based on targeted nanomedicines. Finally, we reviewed the challenges and future perspectives regarding the selection of therapeutic agents, targeting efficiency and the gap between the preclinical and clinical outcome.

Injectable thermosensitive gelling delivery system for the sustained release of lidocaine

BACKGROUND

Patients undergoing arthroplasty require appropriate postsurgical pain relief. Analgesia is typically achieved through bolus doses of short-acting local anesthetics and with oral analgesics such as opiates, which are associated with systemic side effects. By formulating an injectable thermosensitive gelling system containing lidocaine, sustained and local delivery can be achieved following a single administration.

RESULTS

Poloxamer-based thermosensitive gelling formulations were prepared. Altering the weight ratios of poloxamers affected the sol-to-gel transition temperature, mechanical and rheological properties and in vitro drug release. Desirable formulations gelled between 28 and 33°C providing sustained release of lidocaine over 48 h.

CONCLUSION

Thermosensitive gelling systems are promising for sustained drug release following patient administration and may be beneficial in addressing postoperative pain.

PEG-derivatized octacosanol as micellar carrier for paclitaxel delivery

In this study, PEG-derivatized octacosanol copolymer was successfully developed to improve the anti-tumor activity and eliminate toxicity of the commercial formulation of paclitaxel (PTX). MPEG2K-C28, the conjugation of monomethoxy Poly(ethylene glycol) 2000 and octacosanol, was readily soluble in aqueous solution and self-assembled to form micelles with small sizes (< 20 nm) that are efficient in encapsulating PTX with a drug loading of 9.38 ± 0.18% and an encapsulation efficiency of 93.90 ± 2.12%. Meanwhile, octacosanol is very safe for humans and amazingly exhibits antitumor activity through inhibition activity of matrix metalloproteinases (MMPs) and translocation of the transcription factor (nuclear factor-kappa B, NF-κB) to the nucleus, which may be able to promote synergistic effects with PTX. A sustained and slower in vitro release behavior was observed in the (PTX micelles) than that of Taxol. PTX micelles exhibited more potent cytotoxicity than Taxol in the 4T1 breast cancer cell line. More interestingly, MPEG2K-C28 selectively inhibited the growth of 4T1 cells rather than the normal cells (HEK293 and L929 cell lines), indicating the antitumor activity of octacosanol remained after conjugation with MPEG. Acute toxicity evaluations indicated that MPEG2K-C28 was a safe drug carrier. Pharmacokinetic study revealed that PTX micelles improved the T1/2 and AUC of PTX (compared with Taxol) from 1.910 ± 0.139 h and 13.999 ± 1.109 mg/l × h to 2.876 ± 0.532 h and 76.462 ± 8.619 mg/l × h in vivo, respectively. The maximal tolerated dose (MTD) for PTX micelles (ca. 120 mg PTX/kg) in mice was significantly higher than that for Taxol (ca. 20mg PTX/kg). PTX micelles exhibited slightly better antitumor activity than Taxol but safer in 4T1 breast cancer model in vivo. The cell apoptosis in the immunofluorescent studies and the cell proliferation in the immunohistochemical studies also proved the results. In conclusion, MPEG2K-C28 is a simple, safe and effective drug delivery carrier for PTX, and has some therapeutic effects in 4T1 cells in vitro. PTX micelles showed significant antitumor activity in vivo with low systemic toxicity in 4T1 breast cancer. MPEG2K-C28 micelles entrapping PTX deserve more studies in the future.

Self-assembled Micelle Loading Cabazitaxel for therapy of Lung Cancer

Lung cancer is a leading cause of cancer deaths worldwide, chemotherapy has improved overall survival but remains limited at <12 months median overall survival. Cabazitaxel is hopeful to do the same in advanced lung cancer as well as in metastatic prostate cancer. However, its clinical application was restricted due to its high hydrophobicity and severe side effects. To overcome these problems, we developed self-assembled micelle loading cabazitaxel (CBZ-PM) for therapy of lung cancer. The CBZ-PM has high drug loading (10.52%) and encapsulation efficiency (99.30%) with particle size of 28.77 ± 0.52 nm and polydisperse index of 0.114 ± 0.012. The transmission electron microscope image presented its spherical and homogeneous appearance. In vitro release profile showed CBZ-PM has a sustained-release behavior. Furthermore, the result of cell proliferation assays proved that CBZ-PM could induce the Lewis lung carcinoma (LLC) cells death through G2/M arrest more effectively than free CBZ. In vivo anti-tumor activity of CBZ-PM was further studied in mice model of LLC. The tumor inhibitory rate of CBZ-PM was more than 50% and the survival time of LLC bearing mice was efficiently prolonged following administration of CBZ-PM. In addition, the immunohistochemical study showed that more apoptosis cells were detected in the tumor tissue of CBZ-PM group than that of the positive control group. All these indicated that CBZ-PM served as a potential anti-lung cancer agent.

Well-defined labile diselenide-centered poly(ε-caprolactone)-based micelles for activated intracellular drug release

Diselenide groups were introduced into aliphatic polyesters to develop a novel well-defined reduction-labile biodegradable diselenide-containing polymeric drug delivery system (mPEG–PCL–Se)₂.

Polymeric complex micelles based on the double-hydrazone linkage and dual drug-loading strategy for pH-sensitive docetaxel delivery

Complex micelles, which integrated double-hydrazone linkage and dual drug-loading patterns, were constructed for the first time.

An efficient injectable formulation with block copolymer micelles for hydrophobic antitumor candidate-pyridazinone derivatives

Aim: To make delivery improvements via delivery systems for 6-(4-morpholino-3-(trifluoromethyl)phenyl)pyridazin-3(2H)-one (DZO) – a model compound of hydrophobic antitumor candidate pyridazinone derivatives. Materials & methods: Methoxy poly(ethylene glycol)-poly(d,l-lactide) (MPEG-PDLLA) micelle was employed as a vector, and DZO was encapsulated in. The DZO-loaded micelles were characterized in detail and its cytotoxicity, maximum tolerated dose (MTD) and pharmacokinetic experiments were done. In vivo anticancer activity was studied through a subcutaneous 4T1 tumor model. Results: Compared with free DZO, the DZO-loaded micelles possessed a sustained release property, an improved MTD, better pharmacokinetic parameters and an enhanced antitumor activity for subcutaneous 4T1 model in vivo. Conclusion: An effective injectable delivery system for DZO was developed successfully.

Composition controlled synthesis of PCL-PEG Janus nanoparticles: magnetite nanoparticles prepared from one-pot photo-click reaction

The aim of this study is to investigate the effect of polymer nature on the morphology of synthesized nanoparticles. Super paramagnetic iron oxide nanoparticles (SPIONs) were prepared by co-precipitation method and then reacted with (3-mercaptopropyl) trimethoxysilane to obtain thiol-decorated SPIONs. Acrylated poly(caprolactone) and methoxy poly(ethylene glycol) were prepared, and then "thiol-ene click" reaction was performed under UV irradiation to attach two types of polymers on the surface of magnetite nanoparticles via the "photo-click" reaction method. Computational modelling was used for the prediction of the self-assembly of polymers on the surface of SPIONs, which determines the morphology of polymer coated nanoparticles.

Thermogelling polymer-platinum(IV) conjugates for long-term delivery of cisplatin

In this study, we suggest a novel strategy of constituting an in situ-formed hydrogel composed of polymer-platinum(IV) conjugate to realize a long-term delivery of cisplatin. A unique conjugate was designed and synthesized by covalent linking of Pt(IV) complex to the hydrophobic end of two methoxyl poly(ethylene glycol)-b-poly(d,l-lactide) (mPEG-PLA) copolymer chains, resulting in the formation of Bi(mPEG-PLA)-Pt(IV). The conjugate could self-assemble into micelles in water, and its concentrated solution exhibited a thermoreversible sol-gel transition and formed a semisolid thermogel at body temperature. The incorporation of the cisplatin analogue Pt(IV) prodrug into the conjugate had a significant influence on its thermogelling properties and the conjugate thermogelation was attributed to the micellar aggregation. In vitro release experiments of Pt(IV)-conjugated thermogel showed that the platinum release lasted as long as two months. Furthermore, we demonstrated that the Pt(IV) prodrug was released mainly in the form of micelles and micellar aggregates from the gel depot. Compared with free cisplatin, the formation of conjugate micelles led to the enhanced in vitro cytotoxicity against cancer cells due to the effective accumulation into cells via endocytosis.

Thermosensitive mPEG-b-PA-g-PNIPAM comb block copolymer micelles: effect of hydrophilic chain length and camptothecin release behavior

PURPOSE

Block copolymer micelles are extensively used as drug controlled release carriers, showing promising application prospects. The comb or brush copolymers are especially of great interest, whose densely-grafted side chains may be important for tuning the physicochemical properties and conformation in selective solvents, even in vitro drug release. The purpose of this work was to synthesize novel block copolymer combs via atom transfer radical polymerization, to evaluate its physicochemical features in solution, to improve drug release behavior and to enhance the bioavailablity, and to decrease cytotoxicity.

METHODS

The physicochemical properties of the copolymer micelles were examined by modulating the composition and the molecular weights of the building blocks. A dialysis method was used to load hydrophobic camptothecin (CPT), and the CPT release and stability were detected by UV-vis spectroscopy and high-performance liquid chromatography, and the cytotoxicity was evaluated by MTT assays.

RESULTS

The copolymers could self-assemble into well-defined spherical core-shell micelle aggregates in aqueous solution, and showed thermo-induced micellization behavior, and the critical micelle concentration was 2.96-27.64 mg L(-1). The micelles were narrow-size-distribution, with hydrodynamic diameters about 128-193 nm, depending on the chain length of methoxy polyethylene glycol (mPEG) blocks and poly(N-isopropylacrylamide) (PNIPAM) graft chains or/and compositional ratios of mPEG to PNIPAM. The copolymer micelles could stably and effectively load CPT but avoid toxicity and side-effects, and exhibited thermo-dependent controlled and targeted drug release behavior.

CONCLUSIONS

The copolymer micelles were safe, stable and effective, and could potentially be employed as CPT controlled release carriers.

Liposomes interiorly thickened with thermosensitive nanogels as novel drug delivery systems

The fundamental structure of liposomes suffers from drawbacks of physical instability. To overcome this problem, the hypothesis of this study was to thicken the liposomal interior by incorporating thermosensitive in situ gel. The so called gelliposomes (GLs) were prepared by a thin-film method using poloxamer solutions as interior aqueous phase. Interior thermosensitive gelation was proved by observation of sustained dissolving of the poloxamer gel after destroying the lipid bilayers with Triton X-100; structural transformation as observed under optical microscopy in a heating-cooling circle also proved the fact of interior gelling. The sol-gel transition temperatures of GLs were in good correlation with those of the bulk poloxamer solution counterparts, which could be easily tailored by adjusting the concentration and ratio of poloxamer 407 (P407) to poloxamer 188 (P188). Membrane anisotropy measurement indicated increased membrane rigidity. In vitro release of the model drug cytosine arabinoside from GLs showed sustained release characteristics for at least one week with typical biphasic kinetics. Study on storage stability and protection against the destroying effect by membrane destroyers indicated improved physical stability in comparison with conventional liposomes. In situ evading of phagocytic uptake by macrophages was observed for GLs, which however should be attributed to the effect of exteriorly adsorbed poloxamers. In conclusion, GLs present distinct characteristics to be used as potential drug delivery systems.