A reduction-degradable polymer prodrug for cisplatin delivery: Preparation, in vitro and in vivo evaluation

Research on preparation and antitumor activity of redox-responsive polymer micelles co-loaded with sorafenib and curcumin

A novel redox-responsive mPEG-SS-PLA (PSP) polymeric micelle was synthesized and prepared for the delivery of sorafenib (SAF) and curcumin (CUR). And a series of validations were conducted to confirm the structure of the synthesized polymer carriers. Using the Chou-Talalay approach, the combination indexes (CI) of SAF and CUR were determined, and explore the inhibitory effects of the two drugs on HepG2R cells at different ratios. SAF/CUR-PSP polymeric micelles were prepared by thin film hydration method, and the physicochemical properties of nanomicelles were evaluated. The biocompatibility, cell uptake, cell migration, and cytotoxicity assays were assessed in HepG2R cells. The expression of the phosphoinositol-3 kinase (PI3K)/serine/threonine kinase (Akt) signaling pathway was detected by Western blot assay. Additionally, the tumor suppressive effect of SAF/CUR-PSP micelles was clearly superior to free drug monotherapy or their physical combination in HepG2 cell-induced tumor xenografts. The current study revealed that mPEG-SS-PLA polymer micelles loaded with SAF and CUR showed the enhanced therapeutic effects against hepatocellular carcinoma in vitro and in vivo models. It has promising applications for cancer therapy.

An Innovative Polymeric Platform for Controlled and Localized Drug Delivery

Precision medicine aims to optimize pharmacological treatments by considering patients' genetic, phenotypic, and environmental factors, enabling dosages personalized to the individual. To address challenges associated with oral and injectable administration approaches, implantable drug delivery systems have been developed. These systems overcome issues like patient adherence, bioavailability, and first-pass metabolism. Utilizing new combinations of biodegradable polymers, the proposed solution, a Polymeric Controlled Release System (PCRS), allows minimally invasive placement and controlled drug administration over several weeks. This study's objective was to show that the PCRS exhibits a linear biphasic controlled release profile, which would indicate potential as an effective treatment vehicle for cervical malignancies. An injection mold technique was developed for batch manufacturing of devices, and in vitro experiments demonstrated that the device's geometry and surface area could be varied to achieve various drug release profiles. This study's results motivate additional development of the PCRS to treat cervical cancer, as well as other malignancies, such as lung, testicular, and ovarian cancers.

Smart nanomaterials for cancer diagnosis and treatment

Innovations in nanomedicine has guided the improved outcomes for cancer diagnosis and therapy. However, frequent use of nanomaterials remains challenging due to specific limitations like non-targeted distribution causing low signal-to-noise ratio for diagnostics, complex fabrication, reduced-biocompatibility, decreased photostability, and systemic toxicity of nanomaterials within the body. Thus, better nanomaterial-systems with controlled physicochemical and biological properties, form the need of the hour. In this context, smart nanomaterials serve as promising solution, as they can be activated under specific exogenous or endogenous stimuli such as pH, temperature, enzymes, or a particular biological molecule. The properties of smart nanomaterials make them ideal candidates for various applications like biosensors, controlled drug release, and treatment of various diseases. Recently, smart nanomaterial-based cancer theranostic approaches have been developed, and they are displaying better selectivity and sensitivity with reduced side-effects in comparison to conventional methods. In cancer therapy, the smart nanomaterials-system only activates in response to tumor microenvironment (TME) and remains in deactivated state in normal cells, which further reduces the side-effects and systemic toxicities. Thus, the present review aims to describe the stimulus-based classification of smart nanomaterials, tumor microenvironment-responsive behaviour, and their up-to-date applications in cancer theranostics. Besides, present review addresses the development of various smart nanomaterials and their advantages for diagnosing and treating cancer. Here, we also discuss about the drug targeting and sustained drug release from nanocarriers, and different types of nanomaterials which have been engineered for this intent. Additionally, the present challenges and prospects of nanomaterials in effective cancer diagnosis and therapeutics have been discussed.

Reduction-Responsive Anticancer Nanodrug Using a Full Poly(ethylene glycol) Carrier

Poly(ethylene glycol) (PEG) is applied extensively in biomedical fields because of its nontoxic, nonimmunogenic, and protein resistance properties. However, the strong hydrophilicity of PEG prevents it from self-assembling into an amphiphilic micelle in water, making it a challenge to fabricate a full-PEG carrier to deliver hydrophobic anticancer drugs. Herein, a paclitaxel (PTX)-loaded nanodrug was readily prepared through self-assembly of PTX and an amphiphilic PEG derivative, which was synthesized via melt polycondensation of two PEG diols (i.e., PEG₂₀₀ and PEG_10k) and mercaptosuccinic acid. The full PEG component endows the nanocarrier with good biocompatibility. Furthermore, because of the core cross-linked structure via the oxidation of mercapto groups, the nanodrug can be selectively disassociated under an intratumor reductive microenvironment through the reduction of disulfide bonds to release the loaded PTX and kill the cancer cells while maintaining high stability under the extratumor physiological condition. Additionally, it was confirmed that the nanodrug not only prolongs the biocirculation time of PTX but also possesses excellent in vivo antitumor efficacy while avoiding side effects of free PTX, for example, liver damage, which is promising for delivering clinical hydrophobic drugs to treat a variety of malignant tumors.

Smart nanomedicine agents for cancer, triggered by pH, glutathione, H2O2, or H2S

Effective tumor diagnosis and therapy have always been a significant but challenging issue. Although nanomedicine has shown great potential for improving the outcomes of tumor diagnosis and therapy, the nonspecial targeted distribution of nanomedicine agents in the whole body causes a low diagnosis signal-to-noise ratio and a potential risk of systemic toxicity. Recently, the development of smart nanomedicine agents with diagnosis and therapy functions that can only be activated by the tumor microenvironment (TME) is regarded as an effective strategy to improve the theranostic sensitivity and selectivity, as well as reduce the potential side effects during treatment. This article will introduce and summarize the latest achievements in the design and fabrication of TME-responsive smart nanomedicine agents, and highlight their prospects for enhancing tumor diagnosis and therapy.

Advances in redox-responsive drug delivery systems of tumor microenvironment

With the improvement of nanotechnology and nanomaterials, redox-responsive delivery systems have been studied extensively in some critical areas, especially in the field of biomedicine. The system constructed by redox-responsive delivery can be much stable when in circulation. In addition, redox-responsive vectors can respond to the high intracellular level of glutathione and release the loaded cargoes rapidly, only if they reach the site of tumor tissue or targeted cells. Moreover, redox-responsive delivery systems are often applied to significantly improve drug concentrations in targeted cells, increase the therapeutic efficiency and reduce side effects or toxicity of primary drugs. In this review, we focused on the structures and types of current redox-responsive delivery systems and provided a comprehensive overview of relevant researches, in which the disulfide bond containing delivery systems are of the utmost discussion.

Preparation of pH/redox dual responsive polymeric micelles with enhanced stability and drug controlled release

Stimuli-responsive polymeric micelles were prepared through self-assembly of amphiphilic copolymers poly(ethylene glycol)-poly(γ-benzyl l-glutamate), followed by a core-crosslinking reaction using cystamine as the crosslinking agent. The crosslinked micelles with spherical morphologies in nanometer size showed enhanced stability against dilution and concentrated salt solutions compared to the micelles before crosslinking. Doxorubicin (DOX) as a model drug was encapsulated into the core of micelles through electrostatic interactions between carboxylic acid and DOX. In vitro drug release under pH and redox conditions was investigated. Furthermore, the cytotoxicity of micelles was evaluated before and after drug loading. The endocytosis of DOX-loaded micelles and the intracellular drug release were studied. DOX-loaded micelles exhibited accelerated drug release behaviors in an acidic and reductive environment, and showed an inhibited premature release behavior as compared to the noncrosslinked micelles. Considering their enhanced stability, pH and redox dual triggered responsive characteristics, the polymeric micelles can serve as potential systems for controlled drug delivery.

New utilization of Polygonum multiflorum polysaccharide as macromolecular carrier of 5-fluorouracil for controlled release and immunoprotection

WPMP-2 is an acid polysaccharide isolated from Polygonum multiflorum, which demonstrated excellent immunomodulatory activity. In order to reduce immunosuppression of 5-fluorouracil (5-Fu), WPMP-2 was utilized as a macromolecular carrier to conjugate the 5-Fu derivatives 5-fluorouracil-1-acetic acid (5-FUAC) through ester bond. The conjugate showed controlled drug release behaviour in vitro at 37°C in phosphate buffer (pH7.4), and only 5-FUAC was detected in the media. The cytotoxicity test in vitro showed that the conjugate exhibited different cytotoxicity to HepG-2 and HT-29 cells. In addition, immunization study in vivo illustrated that the conjugate displayed immunoprotective effect by mitigating inhibition and damage effects of 5-Fu on secretion of cytokines, proliferation of splenocytes, and phagocytosis of peritoneal macrophages. It was indicated that the conjugation of 5-Fu and WPMP-2 could be a potential double effective drug delivery system.