Micellar carrier based on methoxy poly(ethylene glycol)-block-poly(epsilon-caprolactone) block copolymers bearing ketone groups on the polyester block for doxorubicin delivery

Redox-Responsive Core-Cross-Linked Micelles of Miktoarm Poly(ethylene oxide)-b-poly(furfuryl methacrylate) for Anticancer Drug Delivery

The physiological instability of nanocarriers, premature drug leakage during blood circulation, and associated severe side effects cause compromised therapeutic efficacy, which have significantly hampered the progress of nanomedicines. The cross-linking of nanocarriers while keeping the effectiveness of their degradation at the targeted site to release the drug has emerged as a potent strategy to overcome these flaws. Herein, we have designed novel (poly(ethylene oxide))₂-b-poly(furfuryl methacrylate) ((PEO_2K)₂-b-PFMA_nk) miktoarm amphiphilic block copolymers by coupling alkyne-functionalized PEO (PEO_2K-C≡H) and diazide-functionalized poly(furfuryl methacrylate) ((N₃)₂-PFMA_nk) via click chemistry. (PEO_2K)₂-b-PFMA_nk self-assembled to form nanosized micelles (mikUCL) with hydrodynamic radii in the range of 25∼33 nm. The hydrophobic core of mikUCL was cross-linked by a disulfide-containing cross-linker using the Diels-Alder reaction to avoid unwanted leakage and burst release of a payload. As expected, the resulting core-cross-linked (PEO_2K)₂-b-PFMA_nk micelles (mikCCL) exhibited superior stability under a normal physiological environment and were de-cross-linked to rapidly release doxorubicin (DOX) upon exposure to a reduction environment. The micelles were compatible with HEK-293 normal cells, while DOX-loaded micelles (mikUCL/DOX and mikCCL/DOX) induced high antitumor activity in HeLa and HT-29 cells. mikCCL/DOX preferentially accumulated at the tumor site and was more efficacious than free DOX and mikUCL/DOX for tumor inhibition in HT-29 tumor-bearing nude mice.

Amitriptyline-Based Biodegradable PEG-PLGA Self-Assembled Nanoparticles Accelerate Cutaneous Wound Healing in Diabetic Rats

The aim of this work was to study the healing activity of amitriptyline (Amitrip) in rat diabetic wounds. A nanoformula of the drug was prepared as Amitrip-based biodegradable PEG-PLGA self-assembled nanoparticles (Amitrip-NPs) with a mean particle size of 67.4 nm. An in vivo investigation was conducted to evaluate the wound-healing process of Amitrip-NPs in streptozotocin-induced diabetic rats. Wound contraction was accelerated in rats treated with Amitrip-NPs. Histological examinations confirmed these findings, with expedited remodeling and collagen deposition in the NPs-treated animals. The formula showed anti-inflammatory activities as demonstrated by inhibition of interleukin-6 (IL-6) expression and tumor necrosis factor-α (TNF-α) expression, as well as enhanced expression of interleukin-10 (IL-10). In addition, Amitrip-NPs protected against malondialdehyde (MDA) buildup and superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymatic exhaustion. The pro-collagen activity of Amitrip-NPs was confirmed by the observed enhancement of hydroxyproline wounded skin content, upregulation of Col 1A1 mRNA expression and immune expression of collagen type IV expression. Further, Amitrip-NPs significantly increased expression transforming growth factor-β1 (TGF-β1), vascular endothelial growth factor-A (VEGF-A), platelet-derived growth factor-B (PDGF-B) and cluster of differentiation 31 (CD31). In conclusion, the developed Amitrip-NPs expedited wound healing in diabetic rats. This involves anti-inflammatory, antioxidant, pro-collagen and angiogenic activities of the prepared NPs. This opens the gate for evaluating the usefulness of other structurally related tricyclic antidepressants in diabetic wounds.

A novel polymer micelle as a targeted drug delivery system for 10-hydroxycamptothecin with high drug-loading properties and anti-tumor efficacy

A novel polyethylene glycol-polycaprolactone-poly-l-tyrosine (MPEG-PCL-PTyr) amphiphilic triblock copolymer micelle was synthesized for the first time. 10-hydroxycamptothecin (HCPT) was embedded in MPEG-PCL-PTyr nanomicelles using the emulsion solvent evaporation method. A series of was conducted to confirm the structure of the compound and to evaluate the physical properties of the MPEG-PCL-PTyr nanomicelles. Cellular uptake, cytotoxicity, and apoptosis were assessed using flow cytometry and MTT assays. Confocal microscopy and flow cytometry results demonstrated that the nanocapsules carrying HCPT had significantly increased anti-tumor activity against HepG2 cells and could target HepG2 cell lysosomes with obvious liver targeting. In addition, the drug-loaded nanomicelles could significantly block the S phase of cancer cells and induce apoptosis; thus, they could be potential carriers for future 10-HCPT delivery and cancer treatment.

Multifunctional polymeric micellar nanomedicine in the diagnosis and treatment of cancer

Polymeric micelles are a prevalent topic of research for the past decade, especially concerning their fitting ability to deliver drug and diagnostic agents. This delivery system offers outstanding advantages, such as biocompatibility, high loading efficiency, water-solubility, and good stability in biological fluids, to name a few. The multifunctional polymeric micellar architect offers the added capability to adapt its surface to meet the looked-for clinical needs. This review cross-talks the recent reports, proof-of-concept studies, patents, and clinical trials that utilize polymeric micellar family architectures concerning cancer targeted delivery of anticancer drugs, gene therapeutics, and diagnostic agents. The manuscript also expounds on the underlying opportunities, allied challenges, and ways to resolve their bench-to-bedside translation for allied clinical applications.

pH-responsive nanomicelles of poly(ethylene glycol)-poly(ε-caprolactone)-poly(L-histidine) for targeted drug delivery

Here, a novel pH-responsive block copolymer, poly (ethylene glycol)-poly(ε-caprolactone)-poly(L-histidine) (PEG-PCL-PHis), was synthesized and designed for anti-cancer drug delivery with excellent biocompatible, biodegradable, and strong drug loading efficiency. ¹H-NMR, IF-IR, and GPC were used to characterize the structure of the PEG-PCL-PHis copolymer. In addition, the morphology, particle size, Zeta potential, and critical micelle concentration (CMC) of different degree of polymerization were determined by transmission electron microscopy (TEM), dynamic light scattering granulometer (DLS), and fluorescence spectrometer, respectively. The strong affinity between the core of micelles and hydrophobic drug was manifested with 15.09% drug loading content and 84.65% entrapment efficiency. In vitro release of DOX from the block copolymer micelle demonstrated, the PEG-PCL-PHis copolymer micelle has stable and durable drug releasing ability accompanied with pH-sensitivity. From the mechanism of cellular uptake the micelles, the pathway of drug release was captured by confocal laser scanning microscope. These experiments demonstrated the safe delivery for anticancer medicine through this novel copolymer. In conclusion, the PEG-PCL-PHis copolymer micelle has great potential to become a safe drug carrier for cancer chemotherapy.

Folic acid functionalized long-circulating co-encapsulated docetaxel and curcumin solid lipid nanoparticles: In vitro evaluation, pharmacokinetic and biodistribution in rats

The purpose of this study was to develop folic acid functionalized long-circulating co-encapsulated docetaxel (DTX) and curcumin (CRM) solid lipid nanoparticles (F-DC-SLN) to improve the pharmacokinetic and efficacy of DTX therapy. F-DC-SLN was prepared by hot melt-emulsification method and optimized by face centered-central composite design (FC-CCD). The SLN was characterized in terms of size and size distribution, drug entrapment efficiency and release profile. The cytotoxicity and cell uptake of the SLN formulations were evaluated in MCF-7 and MDA-MB-231 cell lines. The in vivo pharmacokinetic and biodistribution were studied in Wistar rats. F-DC-SLN exhibited 247.5 ± 3.40 nm particle size with 73.88 ± 1.08% entrapment efficiency and zeta potential of 14.53 ± 3.6 mV. Transmission electron microscopy (TEM) revealed spherical morphology of the SLN. Fluorescence microscopy confirmed the targeting efficacy of F-DC-SLN in MCF-7 cells. F-DC-SLN exhibited a significant increase in area under the curve (594.21 ± 64.34 versus 39.05 ± 7.41 μg/mL h) and mean residence time (31.14 ± 19.94 versus 7.24 ± 4.51 h) in comparison to Taxotere®. In addition, decreased DTX accumulation from F-DC-SLN in the heart and kidney in comparison to Taxotere may avoid to toxicity these vital organs. In conclusion, the F-DC-SLN improved the efficacy and pharmacokinetic profile of DTX exhibiting enhanced potential in optimizing breast cancer therapy.

Biodegradable polymeric micelles encapsulated JK184 suppress tumor growth through inhibiting Hedgehog signaling pathway

JK184 can specially inhibit Gli in the Hedgehog (Hh) pathway, which showed great promise for cancer therapeutics. For developing aqueous formulation and improving anti-tumor activity of JK184, we prepared JK184 encapsulated MPEG-PCL micelles by the solid dispersion method without using surfactants or toxic organic solvents. The cytotoxicity and cellular uptake of JK184 micelles were both increased compared with the free drug. JK184 micelles induced more apoptosis and blocked proliferation of Panc-1 and BxPC-3 tumor cells. In addition, JK184 micelles exerted a sustained in vitro release behavior and had a stronger inhibitory effect on proliferation, migration and invasion of HUVECs than free JK184. Furthermore, JK184 micelles had stronger tumor growth inhibiting effects in subcutaneous Panc-1 and BxPC-3 tumor models. Histological analysis showed that JK184 micelles improved anti-tumor activity by inducing more apoptosis, decreasing microvessel density and reducing expression of CD31, Ki67, and VEGF in tumor tissues. JK184 micelles showed a stronger inhibition of Gli expression in Hh signaling, which played an important role in pancreatic carcinoma. Furthermore, circulation time of JK184 in blood was prolonged after entrapment in polymeric micelles. Our results suggested that JK184 micelles are a promising drug candidate for treating pancreatic tumors with a highly inhibitory effect on Hh activity.

Synthesis of functionalized Pluronic-b-poly(ε-caprolactone) and the comparative study of their pendant groups on the cellular internalization behavior

This study focuses on the synthesis of Pluronic-b-poly(ε-caprolactone) bearing benzyl-oxycarbonylmethyl and carboxylic groups and the comparative study to investigate the influence of the different pendant groups on the cellular behavior. The functionalized Pluronic-b-poly(ε-caprolactone) bearing two kinds of pendant groups are synthesized via ring-opening polymerization of ε-caprolactone and 6-(benzyl-oxycarbonyl methyl)-ε-caprolactone and followed by deprotection respectively. The structure of the copolymers is confirmed and the polymeric micelles are formed by an emulsion/solvent evaporation technique. The critical micelle concentrations are improved compared with Pluronic F127, the morphologies of the micelles are spherical with the diameter on nano scale and good colloidal stability. The copolymers have good cytocompatibility and the comparative study reveals that cellular internalization, digesting by lysosome and intracellular distribution are affected by the pendant groups, moreover, the endocytosis pathway is determined by the pendant groups. Therefore, the definite internalization mechanism is beneficial for the design of polymeric micellar carriers to achieve intra- or extracellular modes of drug delivery and provide better access to either cell membrane or intracellular organelles.

PEG-PLGA copolymers: their structure and structure-influenced drug delivery applications

In the paper, we begin by describing polyethylene glycol-poly lactic acid-co-glycolic acid (PEG-PLGA) which was chosen as a typical model copolymer for the construction of nano-sized drug delivery systems and also the types of PEG-PLGA copolymers that were eluted. Following this we examine the structure-influenced drug delivery applications including nanoparticles, micelles and hydrogels. After that, the preparation methods for nano-sized delivery systems are presented. In addition, the drug loading mode of PEG-PLGA micelles is divided into three aspects. Finally, the drug release profiles of PEG-PLGA micelles, both in terms of their in vitro and in vivo characteristics, are represented. PEG-PLGA copolymers are very suitable for the construction of micelles as carriers for insoluble drugs. This article reviews the structure and the different structure-influenced applications of PEG-PLGA copolymers, concentrating on the application of PEG-PLGA micelles.

Comparative studies of poly(ε-caprolactone) and poly(D,L-lactide) as core materials of polymeric micelles

Polymeric micelles have been successfully used to deliver a variety of therapeutic agents. Nonetheless, several limitations and considerations must be clarified and well-studied to achieve the highest therapeutic effect. In this study, a series of methoxy poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-b-PCL) and methoxy poly(ethylene glycol)-block-poly(D,L-lactide) (PEG-b-PLA) with varying molecular weight (MW) of hydrophobic core segment were synthesized. These block copolymers can form micelle with PCL or PLA as core-forming blocks and PEG as a coronal material. The effect of MW on micelle size and critical micelle concentration (CMC) was studied. DOX (DOX) was encapsulated inside the micelle core. Drug-loading content and size of micelles were studied. Drug release studies inside cells were evaluated by confocal laser scanning microscopy. In summary, the PLA core which is less hydrophobic than PCL showed higher CMC, smaller micelle size and faster DOX release inside nucleus.

Self-assembled nanomicelles using PLGA-PEG amphiphilic block copolymer for insulin delivery: a physicochemical investigation and determination of CMC values

Self-assembled nanomicelles can be used as synthetic biomaterials and colloidal carriers for poorly water-soluble drug delivery systems. Some of these micellar systems have been introduced in clinical trials and showed hopeful results relating to their therapeutic index in patients. Biodegradable nanomicelle was prepared from self-assembling amphiphilic block copolymer composed of poly(DL-lactic-co-glycolic acid) (PLGA) as a core and polyethylene glycol (PEG) as a corona. The PLGA-PEG block copolymer was first synthesized and characterized by FTIR, (1)H NMR, GPC and inherent viscosity measurements. The nanomicelle formed by PLGA-PEG block copolymer in the aqueous solution was characterized by dynamic light scattering, zeta potential, scanning electron microscopy (SEM) and fluorescence excitation and emission spectra of pyrene probe. The critical micelle concentration of obtained nanomicelle was about 0.006 mg/mL, with the size of about 160 nm and the zeta potential of -29 mV. Insulin-loaded PLGA-PEG nanomicelles were prepared by modified dialysis method and the physicochemical parameters of the micelles such as drug content, entrapment efficiency and in vitro drug release were characterized. The results showed that insulin was entrapped into PLGA-PEG nanomicelles with drug loading of 3.9 wt% and entrapment efficiency of 55 wt%. The nanomicelles containing insulin exhibited a controlled release profile. These observations suggested that the PLGA-PEG block copolymers nanomicelles have been prepared by a new synthetic route are potent nanocarrier for poorly water-soluble drugs as insulin.

Copolymers: Efficient Carriers for Intelligent Nanoparticulate Drug Targeting and Gene Therapy

Copolymers are among the most promising substances used in the preparation of drug/gene delivery systems. Different categories of copolymers, including block copolymers, graft copolymers, star copolymers and crosslinked copolymers, are of interest in drug delivery. A variety of nanostructures, including polymeric micelles, polymersomes and hydrogels, have been prepared from copolymers and tested successfully for their drug delivery potential. The most recent area of interest in this field is smart nanostructures, which benefit from the stimuli‐responsive properties of copolymeric moieties to achieve novel targeted drug delivery systems. Different copolymer applications in drug/gene delivery using nanotechnology‐based approaches with particular emphasis on smart nanoparticles are reviewed.magnified image

Curcumin-encapsulated MePEG/PCL diblock copolymeric micelles: a novel controlled delivery vehicle for cancer therapy

Aim: To develop a suitable formulation of curcumin-encapsulated methoxy poly(ethylene glycol) (MePEG)/poly-ε-caprolactone (PCL) diblock copolymeric micelle by varying the copolymer ratio, for achieving small sized micelles with high encapsulation of curcumin. To evaluate the micelle’s aqueous solubility and stability, efficiency of cellular uptake, cell cytotoxicity and ability to induce apoptosis on pancreatic cell lines. Method: Amphiphilic diblock copolymers (composed of MePEG and PCL) were used in various ratios for the preparation of curcumin-encapsulated micelles using a modified dialysis method. Physicochemical characterization of the formulation included size and surface charge measurement, transmission electron microscopy characterization, spectroscopic analysis, stability and in vitro release kinetics studies. The anticancer efficacy of the curcumin-encapsulated micelle formulation was compared with unmodified curcumin in terms of cellular uptake, cell cytotoxicity and apoptosis of pancreatic cell lines MIA PaCa-2 and PANC-1. Results: Physiochemical characterization of the formulations revealed that curcumin was efficiently encapsulated in all formulation of MePEG/PCL micelles; however, a 40:60 MePEG:PCL ratio micelle was chosen for experimental studies owing to its high encapsulation (∼60%) with size (∼110 nm) and negative ζ potential (∼-16 mV). Curcumin-encapsulated micelles increased the bioavailability of curcumin due to enhanced uptake (2.95 times more compared with unmodified) with comparative cytotoxic activity (by induction of apoptosis) compared with unmodified curcumin at equimolar concentrations. IC50 values for unmodified curcumin and curcumin micelles were found to be 24.75 µM and 22.8 µM for PANC-1 and 14.96 µM and 13.85 µM for MIA PaCa-2, respectively. Together the results clearly indicate the promise of a micellar system for efficient solubilization, stabilization and controlled delivery of the hydrophobic drug curcumin for cancer therapy.