Polymeric micelles for pH-responsive delivery of cisplatin

Coordinative Double Hydrophilic All-Polyether Micelles for pH-Responsive Delivery of Cisplatin

Despite its widespread use in the treatment of numerous cancers, the use of cisplatin still raises concerns about its high toxicity and limited selectivity. Consequently, the necessity arises for the development of an effective drug delivery system. Here, we present an effective approach that introduces a double hydrophilic block copolyether for the controlled delivery of cisplatin. Specifically, poly(ethylene glycol)-block-poly(glycidoxy acetic acid) (mPEG-b-PGA) was synthesized via anionic ring-opening polymerization using the oxazoline-based epoxide monomer 4,4-dimethyl-2-oxazoline glycidyl ether, followed by subsequent acidic deprotection. The coordinative metal-ligand interaction between cisplatin and the carboxylate group within the PGA block facilitated the formation of micelles from the double hydrophilic mPEG-b-PGA copolyether. Cisplatin-loaded polymeric micelles had a high loading capacity, controlled pH-responsive release kinetics, and high cell viability. Furthermore, in vitro biological assays revealed cellular apoptosis induced by the cisplatin-loaded micelles. This study thus successfully demonstrates the potential use of double hydrophilic block copolyethers as a versatile platform for biomedical applications.

Physiological determinants and plausible '6R' roadmap for clinical success of nanomedicines

Despite the promising features and aggressive research, the success of nanoparticles in clinical trials is minimal. This manuscript discusses the complex biological barriers that impede the journey of nanoparticles to the target site and the approaches used to overcome them. The '6R' framework (right route, right target, right design, right patient, right combination and right technology) is proposed to improve the clinical translation of nanomedicines. Disease-driven approach contrary to the traditional formulation-driven approach is suggested. Data-driven methods can analyze the relationships between various diseases, patient pathophysiology and the physicochemical properties of different nanomedicines, aiding in the precise selection of the most appropriate treatment options. Further research is needed to evaluate and refine these approaches to develop nanomedicines for clinical success.

Stimuli-responsive nanocarrier delivery systems for Pt-based antitumor complexes: a review

Platinum-based anticancer drugs play a crucial role in the clinical treatment of various cancers. However, the application of platinum-based drugs is heavily restricted by their severe toxicity and drug resistance/cross resistance. Various drug delivery systems have been developed to overcome these limitations of platinum-based chemotherapy. Stimuli-responsive nanocarrier drug delivery systems as one of the most promising strategies attract more attention. And huge progress in stimuli-responsive nanocarrier delivery systems of platinum-based drugs has been made. In these systems, a variety of triggers including endogenous and extracorporeal stimuli have been employed. Endogenous stimuli mainly include pH-, thermo-, enzyme- and redox-responsive nanocarriers. Extracorporeal stimuli include light-, magnetic field- and ultrasound responsive nanocarriers. In this review, we present the recent advances in stimuli-responsive drug delivery systems with different nanocarriers for improving the efficacy and reducing the side effects of platinum-based anticancer drugs.

Cisplatin encapsulated nanoparticles from polymer blends for anti-cancer drug delivery

Synthesis of cubic nanostructure for cisplatin encapsulation.

Lipid, polymeric, inorganic-based drug delivery applications for platinum-based anticancer drugs

The three main FDA-approved platinum drugs in chemotherapy such as carboplatin, cisplatin, and oxaliplatin are extensively applied in cancer treatments. Although the clinical applications of platinum-based drugs are extremely effective, their toxicity profile restricts their extensive application. Therefore, recent studies focus on developing new platinum drug formulations, expanding the therapeutic aspect. In this sense, recent advances in the development of novel drug delivery carriers will help with the increase of drug stability and biodisponibility, concomitantly with the reduction of drug efflux and undesirable secondary toxic effects of platinum compounds. The present review describes the state of the art of platinum drugs with their biological effects, pre- and clinical studies, and novel drug delivery nanodevices based on lipids, polymers, and inorganic.

Engineering precision nanoparticles for drug delivery

In recent years, the development of nanoparticles has expanded into a broad range of clinical applications. Nanoparticles have been developed to overcome the limitations of free therapeutics and navigate biological barriers — systemic, microenvironmental and cellular — that are heterogeneous across patient populations and diseases. Overcoming this patient heterogeneity has also been accomplished through precision therapeutics, in which personalized interventions have enhanced therapeutic efficacy. However, nanoparticle development continues to focus on optimizing delivery platforms with a one-size-fits-all solution. As lipid-based, polymeric and inorganic nanoparticles are engineered in increasingly specified ways, they can begin to be optimized for drug delivery in a more personalized manner, entering the era of precision medicine. In this Review, we discuss advanced nanoparticle designs utilized in both non-personalized and precision applications that could be applied to improve precision therapies. We focus on advances in nanoparticle design that overcome heterogeneous barriers to delivery, arguing that intelligent nanoparticle design can improve efficacy in general delivery applications while enabling tailored designs for precision applications, thereby ultimately improving patient outcome overall.

Advances in nanoparticle design could make substantial contributions to personalized and non-personalized medicine. In this Review, Langer, Mitchell, Peppas and colleagues discuss advances in nanoparticle design that overcome heterogeneous barriers to delivery, as well as the challenges in translating these design improvements into personalized medicine approaches.

Double-crosslinked nanocomposite hydrogels for temporal control of drug dosing in combination therapy

Temporal control of drug dosing is indispensable for a successful combination therapy that utilizes cisplatin (CDDP) and irinotecan (IRN), with clinical evidence supporting a higher response rate when CDDP was administered prior to IRN. Herein, a peptide-based nanocomposite hydrogel (CDDP/Pept-AlgNP/IRN) was designed for differential release of CDDP and IRN to maximize synergism of two drugs. First, a double-crosslinking strategy was exploited for structural reinforcement of hydrogel, with integration of coordination interactions between CDDP and hydrogelator (Pept) as well as electrostatic interactions between Pept and alginate nanoparticles (AlgNP/IRN), that afforded nanocomposite hydrogel with 42-fold increase in storage modulus comparing to peptide gel alone. Next, the nanocomposite hydrogel with excellent injectability served as a depot for controlled release of dual drugs, and guaranteed a fast release of CDDP prior to a tunable release of IRN that is dependent on fraction ratios of AlgNP in the composite materials. Comparing to simple mixture of CDDP and IRN solution, CDDP/Pept-AlgNP/IRN hydrogel formulation demonstrated excelling synergism of CDDP and IRN in cell inhibition studies, with efficacious antitumor potency further proved in tumor regression studies in vivo. We believe that the strategy of utilizing co-assembly of multiple pairs of entities (i.e. drug-gelator, nanoparticle-gelator) in composite materials provides a generalized method to design mechanically stable supramolecular hydrogels, and further promises an exact temporal control of drug dosing by packing individual drugs in co-assembled structures/domains to satisfy clinical demands from combination therapy. STATEMENT OF SIGNIFICANCE: This study reports the design of nanocomposite hydrogels with two distinct co-assembling domains for structural reinforcement of hydrogel and differential release of two drugs (CDDP and IRN) in combination therapy. We first investigated the effects of co-assembling processes for the reinforcement of hydrogel. Then we utilized the hydrogel for differential release of CDDP and IRN to achieve better synergistic efficacy of drugs in inhibiting the growth of cancer cell A549 and better anticancer efficacies than single drug formulations or solution mixtures of dual drugs in an A549-xenografted mouse model. We believe that the strategy of packing individual drugs in distinct co-assembling structures promises a paradigm shift for regulating temporal control of drug dosing in combination therapy.

Recent progress in nanotechnology-based novel drug delivery systems in designing of cisplatin for cancer therapy: an overview

Cisplatin cis-(diammine)dichloridoplatinum(II) (CDDP) is the first platinum-based complex approved by the food and drug administration (FDA) of the United States (US). Cisplatin is the first line chemotherapeutic agent used alone or combined with radiations or other anti-cancer agents for a broad range of cancers such as lung, head and neck. Aroplatin™, Lipoplatin™ and SPI-077 are PEGylated liposome-based nano-formulations that are still under clinical trials. They have many limitations, for example, poor aqueous solubility, drug resistance and toxicities, which can be overcome by encapsulating the cisplatin in Nemours nanocarriers. The extensive literature from different electronic databases covers the different nano-delivery systems that are developed for cisplatin. This review critically emphasizes on the recent advancement, development, innovations and updated literature reported for different carrier systems for CDDP.

Preparation and optimization of polymeric micelles as an oral drug delivery system for deferoxamine mesylate: in vitro and ex vivo studies

Deferoxamine mesylate (DFO) is administered as a slow subcutaneous or intravenous infusion due to its poor oral bioavailability and lack of dose proportionality. The aim of the present study was to prepare and optimize polymeric micelles containing DFO, as an oral drug delivery system for increasing permeability and oral bioavailability. Based on a full factorial design with three variables in two levels, eight polymeric micelle formulations were made using film hydration method. Two polymers including 0.1% of carbomer 934 and Poloxamer^®P 407 and two blends of surfactant + co-surfactant including 1 and 2 fold of critical micelle concentration of Labrafil^® + Labrasol^® and Tween 80 + Span 20 were used to prepare polymeric micelles. The effect of variables on particle size (PS), entrapment efficiency (EE), drug release, thermal behavior, in vitro iron bonding and ex vivo rat intestinal permeability were evaluated. The PS of polymeric micelles was less than 83 nm that showed 80% EE with continuous drug release pattern. The change in type of polymer from carbomer to Ploxamer^® significantly increased drug release. All polymeric micelles increased the iron-bonding ability of DFO compared to control. This could be due to surfactants that can play an important role in this ability. Polymeric micelles increased drug permeability through intestine more than 2.5 folds compared to control mainly affected by polymer type. Optimized polymeric micelle consists of Tween 80 and Span 20 with 1.35 folds of critical micelle concentration and Poloxamer^® demonstrated 97.32% iron bonding and a 3-fold increase in permeation through the rat intestine compared with control.

Modulation of Hypoxia-Induced Chemoresistance to Polymeric Micellar Cisplatin: The Effect of Ligand Modification of Micellar Carrier Versus Inhibition of the Mediators of Drug Resistance

Hypoxia can induce chemoresistance, which is a significant clinical obstacle in cancer therapy. Here, we assessed development of hypoxia-induced chemoresistance (HICR) against free versus polymeric cisplatin micelles in a triple negative breast cancer cell line, MDA-MB-231. We then explored two strategies for the modulation of HICR against cisplatin micelles: a) the development of actively targeted micelles; and b) combination therapy with modulators of HICR in MDA-MB-231 cells. Actively targeted cisplatin micelles were prepared through surface modification of acetal-poly(ethylene oxide)-poly(α-carboxyl-ε-caprolactone) (acetal-PEO-PCCL) micelles with epidermal growth factor receptor (EGFR)-targeting peptide, GE11 (YHWYGYTPQNVI). Our results showed that hypoxia induced resistance against free and cisplatin micelles in MDA-MB-231 cells. A significant increase in micellar cisplatin uptake was observed in MDA-MB-231 cells that overexpress EGFR, following surface modification of micelles with GE11. This did not lead to increased cytotoxicity of micellar cisplatin, however. On the other hand, the addition of pharmacological inhibitors of key molecules involved in HICR in MDA-MB-231 cells, i.e., inhibitors of hypoxia inducing factor-1 (HIF-1) and signal transducer and activator of transcription 3 (STAT3), substantially enhanced the cytotoxicity of free and cisplatin micelles. The results indicated the potential benefit of combination therapy with HIF-1 and STAT3 inhibitors in overcoming HICR to free or micellar cisplatin.

Exploiting developments in nanotechnology for the preferential delivery of platinum-based anti-cancer agents to tumours: targeting some of the hallmarks of cancer

Platinum drugs as anti-cancer therapeutics are held in extremely high regard. Despite their success, there are drawbacks associated with their use; their dose-limiting toxicity, their limited activity against an array of common cancers and patient resistance to Pt-based therapeutic regimes. Current investigations in medicinal inorganic chemistry strive to offset these shortcomings through selective targeting of Pt drugs and/or the development of Pt drugs with new or multiple modes of action. A comprehensive overview showcasing how liposomes, nanocapsules, polymers, dendrimers, nanoparticles and nanotubes may be employed as vehicles to selectively deliver cytotoxic Pt payloads to tumour cells is provided.

Extracellular control of intracellular drug release for enhanced safety of anti-cancer chemotherapy

The difficulty of controlling drug release at an intracellular level remains a key challenge for maximising drug safety and efficacy. We demonstrate herein a new, efficient and convenient approach to extracellularly control the intracellular release of doxorubicin (DOX), by designing a delivery system that harnesses the interactions between the system and a particular set of cellular machinery. By simply adding a small-molecule chemical into the cell medium, we could lower the release rate of DOX in the cytosol, and thereby increase its accumulation in the nuclei while decreasing its presence at mitochondria. Delivery of DOX with this system effectively prevented DOX-induced mitochondria damage that is the main mechanism of its toxicity, while exerting the maximum efficacy of this anti-cancer chemotherapeutic agent. The present study sheds light on the design of drug delivery systems for extracellular control of intracellular drug delivery, with immediate therapeutic implications.

PEG based anti-cancer drug conjugated prodrug micelles for the delivery of anti-cancer agents

Development of polymer prodrug conjugates has evolved recently in the nano-medicine field for cancer diagnosis and treatment. This review focuses on the development of different types of PEG based polymer drug conjugates used for the delivery of anti-cancer agents.

Development of Alendronate-conjugated Poly (lactic-co-glycolic acid)-Dextran Nanoparticles for Active Targeting of Cisplatin in Osteosarcoma

In this study, we developed a novel poly (lactic-co-glycolic acid)-dextran (PLD)-based nanodelivery system to enhance the anticancer potential of cisplatin (CDDP) in osteosarcoma cells. A nanosized CDDP-loaded PLGA-DX nanoparticle (PLD/CDDP) controlled the release rate of CDDP up to 48 h. In vitro cytotoxicity assay showed a superior anticancer effect for PLD/CDDP and with an appreciable cellular uptake via endocytosis-mediated pathways. PLD/CDDP exhibited significant apoptosis of MG63 cancer cells compared to that of free CDDP. Approximately ~25% of cells were in early apoptosis phase after PLD/CDDP treatment comparing to ~15% for free CDDP after 48h incubation. Similarly, PLD/CDDP exhibited ~30% of late apoptosis cells comparing to only ~8% for free drug treatment. PLD/CDDP exhibited significantly higher G2/M phase arrest in MG63 cells than compared to free CDDP with a nearly 2-fold higher arrest in case of PLD/CDDP treated group (~60%). Importantly, PLD/CDDP exhibited a most significant anti-tumor activity with maximum tumor growth inhibition. The superior inhibitory effect was further confirmed by a marked reduction in the number of CD31 stained tumor blood vessels and decrease in the Ki67 staining intensity for PLD/CDDP treated animal group. Overall, CDDP formulations could provide a promising and most effective platform in the treatment of osteosarcoma.

Recent developments in micellar drug carriers featuring substituted poly(ε-caprolactone)s

Synthetic modification of caprolactone monomers and polymers provides a route to self-assembling block copolymers for use in drug carrier applications.