Polymeric micelles: authoritative aspects for drug delivery

Oligoelectrolyte-mediated, pH-triggered release of hydrophobic drugs from non-responsive micelles: Influence of oligo(2-vinyl pyridine)-loading on drug-loading, release and cytotoxicity

pH-responsive polymeric micelles have been extensively studied for nanomedicine and take advantage of pH differentials in tissues for the delivery of large doses of cytotoxic drugs at specific target sites. Despite significant advances in this area, there is a lack of versatile and adaptable strategies to render micelles pH-responsive that could be widely applied to different payloads and applications. To address this deficiency, we introduce the concept of oligoelectrolyte-mediated, pH-triggered release of hydrophobic drugs from non-responsive polymeric micelles as a highly effective approach with broad scope. Herein, we investigate the influence of the oligoelectrolyte, oligo(2-vinyl pyridine) (OVP), loading and polymer molecular weight on the pH-sensitivity, drug loading/release and cytotoxicity of poly(ethylene glycol-b-ε-caprolactone) (PEG-b-PCL) micelles using copolymers with either short or long hydrophobic blocks (PEG4PCL4 and PEG10PCL10, respectively). The micelles were characterized as a function of pH (7.4 to 3.5). Dynamic light scattering (DLS) revealed narrow particle size distributions (PSDs) for both the blank and OVP-loaded micelles at pH 7.4. While OVP encapsulation resulted in an increase in the hydrodynamic diameter (Dh) (cf. blank micelles), a decrease in the pH below 6.5 led to a decrease in the Dh consistent with the ionization and release of OVP and core collapse, which were further supported by proton nuclear magnetic resonance (1H NMR) spectroscopy and UV-visible (UV-vis) spectrophotometry. The change in zeta potential (ζ) with pH for the OVP-loaded PEG4PCL4 and PEG10PCL10 micelles was different, suggesting that the location/distribution of OVP in the micelles is influenced by the polymer molecular weight. In general, co-encapsulation of drugs (doxorubicin (DOX), gossypol (GP), paclitaxel (PX) or 7-ethyl-10-hydroxycamptothecin (SN38)) and OVP in the micelles proceeded efficiently with high encapsulation efficiency percentages (EE%). In vitro release studies revealed the rapid, pH-triggered release of drugs from OVP-loaded PEG10PCL10 micelles within hours, with higher OVP loadings providing faster and more complete release. In comparison, no triggered release was observed for the OVP-loaded PEG4PCL4 micelles, implying a strong molecular weight dependency. In metabolic assays the drug- and OVP-loaded PEG10PCL10 micelles were found to result in significant enhancement of the cytotoxicity compared to drug-loaded micelles (no OVP) or other controls. Importantly, micelles with low OVP loadings were found to be nearly as effective as those with high OVP loadings. These results provide key insights into the tunability of the oligoelectrolyte-mediated approach for the effective formulation of pH-responsive micelles and pH-triggered drug release.

Lipase and pH-responsive diblock copolymers featuring fluorocarbon and carboxyl betaine for methicillin-resistant staphylococcus aureus infections

The emergence of multidrug-resistant bacteria along with their resilient biofilms necessitates the development of creative antimicrobial remedies. We designed versatile fluorinated polymer micelles with surface-charge-switchable properties, demonstrating enhanced efficacy against Methicillin-Resistant Staphylococcus Aureus (MRSA) in planktonic and biofilm states. Polymethacrylate diblock copolymers with pendant fluorocarbon chains and carboxyl betaine groups were prepared using reversible addition-fragmentation chain transfer polymerization. Amphiphilic fluorinated copolymers self-assembled into micelles, encapsulating ciprofloxacin in their cores (CIP@FCBMs) for antibacterial and antibiofilm applications. As a control, fluorine-free copolymer micelles loaded with ciprofloxacin (CIP@BCBMs) were prepared. Although both CIP@FCBMs and CIP@BCBMs exhibited pH-responsive surface charges and lipase-triggered drug release, CIP@FCBMs exhibited powerful antimicrobial and antibiofilm activities in vitro and in vivo, attributed to superior serum stability, higher drug loading, enhanced fluorination-facilitated cellular uptake, and lipase-triggered drug release. Collectively, reversing surface charge, on-demand antibiotic release, and fluorination-mediated nanoparticles hold promise for treating bacterial infections and biofilms.

Preparation of novel shell-ionotropically crosslinked micelles based on hexadecylamine and tripolyphosphate for cancer drug delivery

AIMS

Micellar systems have the advantage of being easily prepared, cheap, and readily loadable with bioactive molecular cargo. However, their fundamental pitfall is poor stability, particularly under dilution conditions. We propose to use simple quaternary ammonium surfactants, namely, hexadecylamine (HDA) and hexadecylpyridinium (HDAP), together with tripolyphosphate (TPP) anion, to generate ionotropically stabilized micelles capable of drug delivery into cancer cells.

METHODS

optimized mixed HDA/HDAP micelles were prepared and stabilized with TPP. Curcumin was used as a loaded model drug. The prepared nanoparticles were characterized by dynamic light scattering, infrared spectroscopy, transmission electron microscopy, and differential scanning calorimetry. Moreover, their cellular uptake was assessed using flow cytometry and confocal fluorescence microscopy.

RESULTS

The prepared nanoparticles were found to be stable under dilution and at high temperatures and to have a size range from 139 nm to 580 nm, depending on pH (4.6-7.4), dilution (up to 100 times), and temperature (25 - 80 °C). They were effective at delivering their load into cancer cells. Additionally, flow cytometry indicated the resulting stabilized micellar nanoparticles to be non-cytotoxic.

CONCLUSIONS

The described novel stabilized micelles are simple to prepare and viable for cancer delivery.

Ionic Liquid-Based Polymer Matrices for Single and Dual Drug Delivery: Impact of Structural Topology on Characteristics and In Vitro Delivery Efficiency

Previously reported amphiphilic linear and graft copolymers, derived from the ionic liquid [2-(methacryloyloxy)ethyl]trimethylammonium chloride (TMAMA_Cl‾), along with their conjugates obtained through modification either before or after polymerization with p-aminosalicylate anions (TMAMA_PAS‾), were employed as matrices in drug delivery systems (DDSs). Based on the counterion type in TMAMA units, they were categorized into single drug systems, manifesting as ionic polymers with chloride counterions and loaded isoniazid (ISO), and dual drug systems, featuring ISO loaded in self-assembled PAS conjugates. The amphiphilic nature of these copolymers was substantiated through the determination of the critical micelle concentration (CMC), revealing an increase in values post-ion exchange (from 0.011-0.063 mg/mL to 0.027-0.181 mg/mL). The self-assembling properties were favorable for ISO encapsulation, with drug loading content (DLC) ranging between 15 and 85% in both single and dual systems. In vitro studies indicated ISO release percentages between 16 and 61% and PAS release percentages between 20 and 98%. Basic cytotoxicity assessments using the 2,5-diphenyl-2H-tetrazolium bromide (MTT) test affirmed the non-toxicity of the studied systems toward human non-tumorigenic lung epithelial cell line (BEAS-2B) cell lines, particularly in the case of dual systems bearing both ISO and PAS simultaneously. These results confirmed the effectiveness of polymeric carriers in drug delivery, demonstrating their potential for co-delivery in combination therapy.

Nanocarrier Mediated Intranasal Drug Delivery Systems for the Management of Parkinsonism: A Review

The transport of drugs to the brain becomes a key concern when treating disorders of the central nervous system. Parkinsonism is one of the major concerns across the world populations, which causes difficulty in coordination and balance. However, the blood-brain barrier is a significant barrier to achieving optimal brain concentration through oral, transdermal, and intravenous routes of administration. The intranasal route with nanocarrier-based formulations has shown potential for managing Parkinsonism disorder (PD). Direct delivery to the brain through the intranasal route is possible via the olfactory and trigeminal pathways using drug-loaded nanotechnology-based drug delivery systems. The critical analysis of reported works demonstrates dose reduction, brain targeting, safety, effectiveness, and stability for drug-loaded nanocarriers. The important aspects of intranasal drug delivery, PD details, and nanocarrier-based intranasal formulations in PD management with a discussion of physicochemical characteristics, cell line studies, and animal studies are the major topics in this review. Patent reports and clinical investigations are summarized in the last sections.

Norcantharidin-Encapsulated C60-Modified Nanomicelles: A Potential Approach to Mitigate Cytotoxicity in Renal Cells and Simultaneously Enhance Anti-Tumor Activity in Hepatocellular Carcinoma Cells

OBJECTIVE

The objective of this study was to examine the preparation process of DSPE-PEG-C60/NCTD micelles and assess the impact of fullerenol (C60)-modified micelles on the nephrotoxicity and antitumor activity of NCTD.

METHOD

The micelles containing NCTD were prepared using the ultrasonic method and subsequently optimized and characterized. The cytotoxicity of micelles loaded with NCTD was assessed using the CCK-8 method on human hepatoma cell lines HepG2 and BEL-7402, as well as normal cell lines HK-2 and L02. Acridine orange/ethidium bromide (AO/EB) double staining and flow cytometry were employed to assess the impact of NCTD-loaded micelles on the apoptosis of the HK-2 cells and the HepG2 cells. Additionally, JC-1 fluorescence was utilized to quantify the alterations in mitochondrial membrane potential. The generation of reactive oxygen species (ROS) following micelle treatment was determined through 2',7'-dichlorofluorescein diacetate (DCFDA) staining.

RESULTS

The particle size distribution of the DSPE-PEG-C60/NCTD micelles was determined to be 91.57 nm (PDI = 0.231). The zeta potential of the micelles was found to be -13.8 mV. The encapsulation efficiency was measured to be 91.9%. The in vitro release behavior of the micelles followed the Higuchi equation. Cellular experiments demonstrated a notable decrease in the toxicity of the C60-modified micelles against the HK-2 cells, accompanied by an augmented inhibitory effect on cancer cells. Compared to the free NCTD group, the DSPE-PEG-C60 micelles exhibited a decreased apoptosis rate (12%) for the HK-2 cell line, lower than the apoptosis rate observed in the NCTD group (36%) at an NCTD concentration of 75 μM. The rate of apoptosis in the HepG2 cells exhibited a significant increase (49%), surpassing the apoptosis rate observed in the NCTD group (24%) at a concentration of 150 μM NCTD. The HK-2 cells exhibited a reduction in intracellular ROS and an increase in mitochondrial membrane potential (ΔψM) upon exposure to C60-modified micelles compared to the NCTD group.

CONCLUSIONS

The DSPE-PEG-C60/NCTD micelles, as prepared in this study, demonstrated the ability to decrease cytotoxicity and ROS levels in normal renal cells (HK-2) in vitro. Additionally, these micelles showed an enhanced antitumor activity against human hepatocellular carcinoma cells (HepG2, BEL-7402).

Polymeric-Micelle-Based Delivery Systems for Nucleic Acids

Nucleic acids can modulate gene expression specifically. They are increasingly being utilized and show huge potential for the prevention or treatment of various diseases. However, the clinical translation of nucleic acids faces many challenges due to their rapid clearance after administration, low stability in physiological fluids and limited cellular uptake, which is associated with an inability to reach the intracellular target site and poor efficacy. For many years, tremendous efforts have been made to design appropriate delivery systems that enable the safe and effective delivery of nucleic acids at the target site to achieve high therapeutic outcomes. Among the different delivery platforms investigated, polymeric micelles have emerged as suitable delivery vehicles due to the versatility of their structures and the possibility to tailor their composition for overcoming extracellular and intracellular barriers, thus enhancing therapeutic efficacy. Many strategies, such as the addition of stimuli-sensitive groups or specific ligands, can be used to facilitate the delivery of various nucleic acids and improve targeting and accumulation at the site of action while protecting nucleic acids from degradation and promoting their cellular uptake. Furthermore, polymeric micelles can be used to deliver both chemotherapeutic drugs and nucleic acid therapeutics simultaneously to achieve synergistic combination treatment. This review focuses on the design approaches and current developments in polymeric micelles for the delivery of nucleic acids. The different preparation methods and characteristic features of polymeric micelles are covered. The current state of the art of polymeric micelles as carriers for nucleic acids is discussed while highlighting the delivery challenges of nucleic acids and how to overcome them and how to improve the safety and efficacy of nucleic acids after local or systemic administration.

Structural Behavior of Amphiphilic Triblock Copolymer P104/Water System

A detailed study of the different structural transitions of the triblock copolymer PEO₂₇-PPO₆₁-PEO₂₇ (P104) in water, in the dilute and semi-dilute regions, is addressed here as a function of temperature and P104 concentration (C_P104) by mean of complimentary methods: viscosimetry, densimetry, dynamic light scattering, turbidimetry, polarized microscopy, and rheometry. The hydration profile was calculated through density and sound velocity measurements. It was possible to identify the regions where monomers exist, spherical micelle formation, elongated cylindrical micelles formation, clouding points, and liquid crystalline behavior. We report a partial phase diagram including information for P104 concentrations from 1 × 10^-4 to 90 wt.% and temperatures from 20 to 75 °C that will be helpful for further interaction studies with hydrophobic molecules or active principles for drug delivery.

Dapsone-Loaded Mixed Micellar Gel for Treatment OF Acne Vulgaris

Mixed polymeric micelles are potential nanocarriers for topical drug delivery. Dapsone (DAP) is an antibacterial used as anti-acne agent, but challenged by low water solubility and poor skin permeability. In the present study, DAP-loaded mixed micellar gel was developed comprising Pluronics F-68 and F-127. Micelles were prepared by solvent evaporation method and particle size, ex vivo permeation, drug loading, and entrapment efficiency were determined. Central Composite Design was used to optimize formulation. Independent variables were concentration of Pluronics at three levels while micelle size and drug loading capacities were dependent variables. Droplet size ranged from 400 to 500 nm. Transmission electron microscopy revealed spherical morphology of micelles. Optimized micelles were incorporated into gel base using HPMC K100M, Sodium CMC, and Carbopol 980 as gelling agents. Gels were evaluated for pH, drug content, spreadability, rheology, syneresis, ex vivo permeation, and subacute dermal toxicity. Compared with solubility of free DAP (0.24+0.056 µg/ml), solubility in mixed micelles was 18.42±3.4 µg/ml in water at room temperature. Order of spreadability of gels was Na CMC < HPMC < Carbopol 980. Carbopol gels displayed thixotropy with index of 3.17. Syneresis for all gels from day 0 to day 30 was found to be in range of 4.2 to 15.6% w/w. Subacute dermal toxicity studies showed no signs of erythema and edema on rat skin until 21 days. These results suggest that mixed micelles can significantly increase solubility and permeability and sustain release of DAP and are suitable carriers for topical DAP delivery in anti-acne therapies.

Superior possibilities and upcoming horizons for nanoscience in COVID-19: noteworthy approach for effective diagnostics and management of SARS-CoV-2 outbreak

The outbreak of COVID-19 has caused great havoc and affected many parts of the world. It has imposed a great challenge to the medical and health fraternity with its ability to continue mutating and increasing the transmission rate. Some challenges include the availability of current knowledge of active drugs against the virus, mode of delivery of the medicaments, its diagnosis, which are relatively limited and do not suffice for further prognosis. One recently developed drug delivery system called nanoparticles is currently being utilized in combating COVID-19. This article highlights the existing methods for diagnosis of COVID-19 such as computed tomography scan, reverse transcription-polymerase chain reaction, nucleic acid sequencing, immunoassay, point-of-care test, detection from breath, nanotechnology-based bio-sensors, viral antigen detection, microfluidic device, magnetic nanosensor, magnetic resonance platform and internet-of-things biosensors. The latest detection strategy based on nanotechnology, biosensor, is said to produce satisfactory results in recognizing SARS-CoV-2 virus. It also highlights the successes in the research and development of COVID-19 treatments and vaccines that are already in use. In addition, there are a number of nanovaccines and nanomedicines currently in clinical trials that have the potential to target COVID-19.

Recent Progress in Proteins-Based Micelles as Drug Delivery Carriers

Proteins-derived polymeric micelles have gained attention and revolutionized the biomedical field. Proteins are considered a favorable choice for developing micelles because of their biocompatibility, harmlessness, greater blood circulation and solubilization of poorly soluble drugs. They exhibit great potential in drug delivery systems as capable of controlled loading, distribution and function of loaded agents to the targeted sites within the body. Protein micelles successfully cross biological barriers and can be incorporated into various formulation designs employed in biomedical applications. This review emphasizes the recent advances of protein-based polymeric micelles for drug delivery to targeted sites of various diseases. Most studied protein-based micelles such as soy, gelatin, casein and collagen are discussed in detail, and their applications are highlighted. Finally, the future perspectives and forthcoming challenges for protein-based polymeric micelles have been reviewed with anticipated further advances.

Cyclodextrin-Based Arsenal for Anti-Cancer Treatments

Anti-cancer drugs are mostly limited in their use due to poor physicochemical and biopharmaceutical properties. Their lower solubility is the most common hurdle limiting their use upto their potential. In the recent years, the cyclodextrin (CD) complexation have emerged as existing approach to overcome the problem of poor solubility. CD-based nano-technological approaches are safe, stable and showed well in vivo tolerance and greater payload for encapsulation of hydrophobic drugs for the targeted delivery. They are generally chosen due to their ability to get self-assembled to form liposomes, nanoparticles, micelles and nano-sponges etc. This review paper describes a birds-eye view of the various CD-based nano-technological approaches applied for the delivery of anti-cancer moieties to the desired target such as CD based liposomes, niosomes, niosoponges, micelles, nanoparticles, monoclonal antibody, magnetic nanoparticles, small interfering RNA, nanorods, miscellaneous formulation of anti-cancer drugs containing CD. Moreover, the author also summarizes the various shortcomings of such a system and their way ahead.

Theranostics for Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with poor prognosis. Current endocrine therapy or anti HER-2 therapy is not available for these patients. Chemotherapeutic treatment response varies among patients due to the disease heterogeneity. To overcome these challenges, theranostics for treating TNBC have been widely investigated. Anticancer material conjugated nanoparticles with target-binding ligand and tracer agents enable simultaneous drug delivery and visualization of the lesion with minimal off-target toxicity. In this review, we summarize recently FDA-approved targeted therapies for TNBC, such as poly-ADP-ribose polymerase (PARP) inhibitors, check point inhibitors, and antibody-drug conjugates. Particularly, novel theranostic approaches including lipid-based, polymer-based, and carbon-based nanocarriers are discussed, which can provide basic overview of nano-therapeutic modalities in TNBC diagnosis and treatment.

Polymeric micelles and cancer therapy: an ingenious multimodal tumor-targeted drug delivery system

Since the beginning of pharmaceutical research, drug delivery methods have been an integral part of it. Polymeric micelles (PMs) have emerged as multifunctional nanoparticles in the current technological era of nanocarriers, and they have shown promise in a range of scientific fields. They can alter the release profile of integrated pharmacological substances and concentrate them in the target zone due to their improved permeability and retention, making them more suitable for poorly soluble medicines. With their ability to deliver poorly soluble chemotherapeutic drugs, PMs have garnered considerable interest in cancer. As a result of their remarkable biocompatibility, improved permeability, and minimal toxicity to healthy cells, while also their capacity to solubilize a wide range of drugs in their micellar core, PMs are expected to be a successful treatment option for cancer therapy in the future. Their nano-size enables them to accumulate in the tumor microenvironment (TME) via the enhanced permeability and retention (EPR) effect. In this review, our major aim is to focus primarily on the stellar applications of PMs in the field of cancer therapeutics along with its mechanism of action and its latest advancements in drug and gene delivery (DNA/siRNA) for cancer, using various therapeutic strategies such as crossing blood-brain barrier, gene therapy, photothermal therapy (PTT), and immunotherapy. Furthermore, PMs can be employed as "smart drug carriers," allowing them to target specific cancer sites using a variety of stimuli (endogenous and exogenous), which improve the specificity and efficacy of micelle-based targeted drug delivery. All the many types of stimulants, as well as how the complex of PM and various anticancer drugs react to it, and their pharmacodynamics are also reviewed here. In conclusion, commercializing engineered micelle nanoparticles (MNPs) for application in therapy and imaging can be considered as a potential approach to improve the therapeutic index of anticancer drugs. Furthermore, PM has stimulated intense interest in research and clinical practice, and in light of this, we have also highlighted a few PMs that have previously been approved for therapeutic use, while the majority are still being studied in clinical trials for various cancer therapies.

Direct and Reverse Pluronic Micelles: Design and Characterization of Promising Drug Delivery Nanosystems

Pluronics are a family of amphiphilic block copolymers broadly explored in the pharmaceutical field. Under certain conditions, Pluronics self-assemble in different structures including nanosized direct and reverse micelles. This review provides an overview about the main parameters affecting the micellization process of Pluronics, such as polymer length, fragments distribution within the chain, solvents, additives and loading of cargo. Furthermore, it offers a guide about the most common techniques used to characterize the structure and properties of the micelles. Finally, it presents up-to-date approaches to improve the stability and drug loading of Pluronic micelles. Special attention is paid to reverse Pluronics and reverse micelles, currently underexplored in the literature. Pluronic micelles present a bright future as drug delivery agents. A smart design and thorough characterization will improve the transfer to clinical applications.

How Choice of Model Membrane Affects Protein–Glycosphingolipid Interactions: Insights from Native Mass Spectrometry

Interactions between glycan-binding proteins (GBPs) and glycosphingolipids (GSLs) are involved in numerous physiological and pathophysiological processes. Many model membrane systems are available for studying GBP-GSL interactions, but a systematic investigation has not been carried out on how the nature of the model membrane affects binding. In this work, we use electrospray ionization mass spectrometry (ESI-MS), both direct and competitive assays, to measure the binding of cholera toxin B subunit homopentamer (CTB₅) to GM1 ganglioside in liposomes, bilayer islands [styrene maleic acid lipid particles (SMALPs), nanodiscs (NDs), and picodiscs (PDs)], and micelles. We find that direct ESI-MS analysis of CTB₅ binding to GM1 is unreliable due to non-uniform response factors, incomplete extraction of bound GM1 in the gas phase, and nonspecific CTB₅-GM1 interactions. Conversely, indirect proxy ligand ESI-MS measurements show that the intrinsic (per binding site) association constants of CTB₅ for PDs, NDs, and SMALPs are similar and comparable to the affinity of soluble GM1 pentasaccharide (GM1_os). The observed affinity decreases with increasing GM1 content due to molecular crowding stemming from GM1 clustering. Unlike the smaller model membranes, the observed affinity of CTB₅ toward GM1 liposomes is ∼10-fold weaker than GM1_os and relatively insensitive to the GM1 content. GM1 glycomicelles exhibit the lowest affinity, ∼35-fold weaker than GM1_os. Together, the results highlight experimental design considerations for quantitative GBP-GSL binding studies involving multisubunit GBPs and factors to consider when comparing results obtained with different membrane systems. Notably, they suggest that bilayer islands with a low percentage of GSL, wherein clustering is minimized, are ideal for assessing intrinsic strength of GBP-GSL interactions in a membrane environment, while binding to liposomes, which is sub-optimal due to extensive clustering, may be more representative of authentic cellular environments.

Curcumin-Encapsulated Nanomicelles Improve Cellular Uptake and Cytotoxicity in Cisplatin-Resistant Human Oral Cancer Cells

Oral cancer has a high mortality rate, which is mostly determined by the stage of the disease at the time of admission. Around half of all patients with oral cancer report with advanced illness. Hitherto, chemotherapy is preferred to treat oral cancer, but the emergence of resistance to anti-cancer drugs is likely to occur after a sequence of treatments. Curcumin is renowned for its anticancer potential but its marred water solubility and poor bioavailability limit its use in treating multidrug-resistant cancers. As part of this investigation, we prepared and characterized Curcumin nanomicelles (CUR-NMs) using DSPE-PEG-2000 and evaluated the anticancer properties of cisplatin-resistant cancer cell lines. The prepared CUR-NMs were sphere-shaped and unilamellar in structure, with a size of 32.60 ± 4.2 nm. CUR-NMs exhibited high entrapment efficiency (82.2%), entrapment content (147.96 µg/mL), and a mean zeta potential of −17.5ζ which is considered moderately stable. The cellular uptake and cytotoxicity studies revealed that CUR-NMs had significantly higher cytotoxicity and cellular uptake in cisplatin drug-resistant oral cancer cell lines and parental oral cancer cells compared to plain curcumin (CUR). The DAPI and FACS analysis corroborated a high percentage of apoptotic cells with CUR-NMs (31.14%) compared to neat CUR (19.72%) treatment. Conclusively, CUR-NMs can potentially be used as an alternative carrier system to improve the therapeutic effects of curcumin in the treatment of cisplatin-resistant human oral cancer.

Gradient copolymers versus block copolymers: self-assembly in solution and surface adsorption

The structures of amphiphilic block and gradient copolymers in solution and adsorbed onto surfaces are surveyed using molecular-dynamics simulations. A bead-spring model is used to identify the general effects of the different architectures: block and gradient copolymers have equal numbers of solvophilic and solvophobic beads, and the gradient copolymer is represented by a linear concentration profile along the chain. Each type of isolated copolymer forms a structure with a globular head of solvophobic beads, and a coil-like tail of solvophilic beads. The radius of gyration of a gradient copolymer is found to be much more sensitive to temperature than that of a block copolymer due to an unravelling mechanism. At finite concentrations, both gradient and block copolymers self-assemble into micelles, with the gradient copolymers again showing a larger temperature dependence. The micelles are characterised using simulated scattering profiles, which compare favourably to existing experimental data. The adsorption of copolymers onto structureless surfaces is modelled with an attractive potential that is selective for the solvophobic beads, and the surface structures are characterised using the average height of the molecules, and the proportion of beads adsorbed. Both types of copolymer form adsorbed films with persistent micelle-like structures, but the gradient copolymers show a stronger dependence on the strength of the surface interactions and the temperature. Coarse-grained, bead-spring models allow a rapid survey and comparison of the block and gradient architectures, and the results set the scene for future work with atomistic simulations. A superficial but favourable comparison is made between the results from the bead-spring models, and atomistic simulations of a butyl prop-2-enoate/prop-2-enoic acid (butyl acrylate/acrylic acid) copolymer in n-dodecane at room temperature.

Synthesis and Evaluation of Thermoresponsive Renewable Lipid-Based Block Copolymers for Drug Delivery

Polymeric micelle forming from self-assembly of amphiphilic macromolecules is one of the most potent drug delivery systems. Fatty acids, naturally occurring hydrophobic lipid components, can be considered as potential candidates for the fabrication of block copolymer micelles. However, examples of synthesis of responsive block copolymers using renewable fatty acids are scarce. Herein, we report the synthesis, characterization and testing of block copolymer micelles composed of a renewable fatty-acid-based hydrophobic block and thermoresponsive hydrophilic block for controlled drug delivery. The block copolymers of functionalized fatty acid and poly(N-isopropylacrylamide) (PNIPAM) were prepared via consecutive microwave-assisted reversible addition fragmentation chain transfer (RAFT) polymerization. The block copolymers with variable hydrophobic block length self-assembled in aqueous media and formed spherical nanoparticles of ~30 nm with low critical micelle concentration (CMC). To demonstrate the proof-of-concept, carbamazepine (CBZ) was used as a hydrophobic model drug to evaluate the performance of these micelles as nanocarriers. The in vitro drug release tests were carried out below (25 °C) and above (37 °C) the lower critical solution temperature (LCST) of the block copolymer. The drug release showed obvious temperature-triggered response and an accelerated drug release at 37 °C.

New Advances in Biomedical Application of Polymeric Micelles

In the last decade, nanomedicine has arisen as an emergent area of medicine, which studies nanometric systems, namely polymeric micelles (PMs), that increase the solubility and the stability of the encapsulated drugs. Furthermore, their application in dermal drug delivery is also relevant. PMs present unique characteristics because of their unique core-shell architecture. They are colloidal dispersions of amphiphilic compounds, which self-assemble in an aqueous medium, giving a structure-type core-shell, with a hydrophobic core (that can encapsulate hydrophobic drugs), and a hydrophilic shell, which works as a stabilizing agent. These features offer PMs adequate steric protection and determine their hydrophilicity, charge, length, and surface density properties. Furthermore, due to their small size, PMs can be absorbed by the intestinal mucosa with the drug, and they transport the drug in the bloodstream until the therapeutic target. Moreover, PMs improve the pharmacokinetic profile of the encapsulated drug, present high load capacity, and are synthesized by a reproducible, easy, and low-cost method. In silico approaches have been explored to improve the physicochemical properties of PMs. Based on this, a computer-aided strategy was developed and validated to enable the delivery of poorly soluble drugs and established critical physicochemical parameters to maximize drug loading, formulation stability, and tumor exposure. Poly(2-oxazoline) (POx)-based PMs display unprecedented high loading concerning water-insoluble drugs and over 60 drugs have been incorporated in POx PMs. Among various stimuli, pH and temperature are the most widely studied for enhanced drug release at the site of action. Researchers are focusing on dual (pH and temperature) responsive PMs for controlled and improved drug release at the site of action. These dual responsive systems are mainly evaluated for cancer therapy as certain malignancies can cause a slight increase in temperature and a decrease in the extracellular pH around the tumor site. This review is a compilation of updated therapeutic applications of PMs, such as PMs that are based on Pluronics^®, micelleplexes and Pox-based PMs in several biomedical applications.

Progress in Polymeric Micelles for Drug Delivery Applications

Polymeric micelles (PMs) have made significant progress in drug delivery applications. A robust core-shell structure, kinetic stability and the inherent ability to solubilize hydrophobic drugs are the highlights of PMs. This review presents the recent advances and understandings of PMs with a focus on the latest drug delivery applications. The types, methods of preparation and characterization of PMs are described along with their applications in oral, parenteral, transdermal, intranasal and other drug delivery systems. The applications of PMs for tumor-targeted delivery have been provided special attention. The safety, quality and stability of PMs in relation to drug delivery are also provided. In addition, advanced polymeric systems and special PMs are also reviewed. The in vitro and in vivo stability assessment of PMs and recent understandings in this area are provided. The patented PMs and clinical trials on PMs for drug delivery applications are considered indicators of their tremendous future applications. Overall, PMs can help overcome many unresolved issues in drug delivery.

Pinocembrin polymeric micellar drug delivery system: preparation, characterisation and anti-hyperuricemic activity evaluation

Aim: Hydrophobic pinocembrin (PCB) was incorporated into a new nano-drug delivery system to enhance solubility, bioavailability and anti-hyperuricemic activity of the drug.Methods: We fabricated PCB loaded polymeric micelles (PCB-FPM) by thin film dispersion method and appropriately determined their physical characteristics. The oral relative bioavailability and anti-hyperuricemic activity of PCB-FPM and free PCB were observed.Results: The optimum particle size of the micelles was 19.90 ± 0.93 nm. PCB-FPM exhibited great stability within 18 days, coupled with lower cytotoxicity and higher biocompatibility. Moreover, the percent cumulative release of PCB-FPM was much higher than free PCB in the dissolution media. The oral bioavailability of PCB-FPM was increased by 2.61 times compared with free PCB. Uric acid (UA) level of rats was reduced in PCB-FPM group (200 mg/kg) by 78.82% comparable to the model control.Conclusion: PCB-FPM may become an ideal strategy to increase oral in-vivo availability and anti-hyperuricemic activity of PCB.

A Review of Polymeric Micelles and Their Applications

Self-assembly of amphiphilic polymers with hydrophilic and hydrophobic units results in micelles (polymeric nanoparticles), where polymer concentrations are above critical micelle concentrations (CMCs). Recently, micelles with metal nanoparticles (MNPs) have been utilized in many bio-applications because of their excellent biocompatibility, pharmacokinetics, adhesion to biosurfaces, targetability, and longevity. The size of the micelles is in the range of 10 to 100 nm, and different shapes of micelles have been developed for applications. Micelles have been focused recently on bio-applications because of their unique properties, size, shape, and biocompatibility, which enhance drug loading and target release in a controlled manner. This review focused on how CMC has been calculated using various techniques. Further, micelle importance is explained briefly, different types and shapes of micelles are discussed, and further extensions for the application of micelles are addressed. In the summary and outlook, points that need focus in future research on micelles are discussed. This will help researchers in the development of micelles for different applications.

A Novel Study on the Self-Assembly Behavior of Poly(lactic-co-glycolic acid) Polymer Probed by Curcumin Fluorescence

Understanding the self-assembly behavior of block copolymers is of great importance due to their usefulness in a wide range of applications. In this work, the physical properties of poly(lactic-co-glycolic acid) (PLGA polymer) are studied for the first time in solution using the fluorescence technique and curcumin as a molecular probe. First, curcumin at a concentration of 2 μM was added to different concentrations of PLGA, and the fluorescence of curcumin was tracked. It was found that the critical micellar concentration (CMC) was equal to 0.31 g/L and the critical micellar temperature (CMT) was obtained to be 25 °C. Furthermore, an insight on the effect of NaCl salt on the CMC value of PLGA is assessed through curcumin probing. A decrease in the CMC has been observed with the increase in the concentration of NaCl, which could be due to the salting out effect. Moreover, in order to understand the aggregation behavior of PLGA in different solutions, CMC experiments were investigated using chloroform as a solvent. Results showed that the solvent does not affect the CMC value of the polymer; however, it only affects the shape of the obtained micelle forming a reversed micelle. Finally, fluorescence quenching of curcumin with hydrophobic cetyl-pyridinium bromide (CPB) and hydrophilic KI quenchers was established, where it was proved that curcumin is located near the hydrophobic pocket of the Stern layer of the PLGA micelle.

Rutin-loaded polymeric nanorods alleviate nephrolithiasis by inhibiting inflammation and oxidative stress in vivo and in vitro

Polycrystalline aggregates formed in the glomerulus or other components of the urinary system represent the most critical step in kidney stone formation. The most common form of these crystals is calcium oxalate monohydrate (CaC₂O₄·H₂O). Rutin is a potent antioxidant phytochemical, however, hydrophobicity and limited bioavailability restrain it from clinical applications. We developed a biocompatible amphiphilic triblock copolymer, PLGA-PEG-PLGA-loaded rutin nanorods, by simple and efficient self-assembly. Incorporation of polymer changed the topology of crystalline rutin into nanorods with non-Fickian sustained drug release kinetics by the Korsmeyer-Peppas model and thermodynamically non-spontaneous release of rutin. Rutin nanorods changed the growth and morphology of CaC₂O₄ crystals from the monohydrate to dihydrate form by increased adsorption and specific surface area from 0.8027 to 5.4233 m² g^-1, respectively. Rutin nanorods restored cell viability and oxidative stress in MDCK cells by modulating OPN expression and counteracts the proinflammatory signaling in THP-1 macrophages triggered by CaC₂O₄ crystals (80 μg cm^-2). Rutin nanorods resulted in significant protection in serum and urinary biochemistry with reduced calcifications and increased tissue viability of kidneys without any toxicity and achieved high bioavailability. Our data provide a facile strategy for the use of rutin nanorods as a targeted drug system to treat and prevent renal stone formations.

Mixed Polymeric Micelles for Rapamycin Skin Delivery

Facial angiofibromas (FA) are one of the most obvious cutaneous manifestations of tuberous sclerosis complex. Topical rapamycin for angiofibromas has been reported as a promising treatment. Several types of vehicles have been used hitherto, but polymeric micelles and especially those made of d-α-tocopherol polyethylene glycol 1000 succinate (TPGS) seem to have shown better skin bioavailability of rapamycin than the so far commonly used ointments. To better understand the influence of polymeric micelles on the behavior of rapamycin, we explored it through mixed polymeric micelles combining TPGS and poloxamer, evaluating stability and skin bioavailability to define an optimized formulation to effectively treat FA. Our studies have shown that TPGS improves the physicochemical behavior of rapamycin, i.e., its solubility and stability, due to a strong inclusion in micelles, while poloxamer P123 has a more significant influence on skin bioavailability. Accordingly, we formulated mixed-micelle hydrogels containing 0.1% rapamycin, and the optimized formulation was found to be stable for up to 3 months at 2–8 °C. In addition, compared to hydroalcoholic gel formulations, the studied system allows for better biodistribution on human skin.

Aceclofenac-loaded pluronic F108/L81 mixed polymeric micelles: effect of HLB on solubilization

Pluronic block copolymers have phase behavioural characteristics which are extensively studied for drug delivery applications. In this study, we explored hydrophilic pluronic F108 (HLB = 27), hydrophobic pluronic L81 (HLB = 2) and their mixed micelles acting as solubilising mediums for model drug aceclofenac. The drug solubilisation and interactions have been analysed using UV-visible spectroscopy, Fluorescence spectroscopy, Rheology studies, Fourier-transform infrared spectroscopy, Scanning electron microscope, Dynamic light scattering, Cloud point and partition coefficient measurements. The investigation from UV-spectrophotometry demonstrated that mixed pluronic entrapped greater number of aceclofenac molecules than both the neat pluronics at same concentration. Excimer formation was evidenced from fluorescence spectra with pyrene as a probe. The rheological studies showed difference in viscosity over low shear range. Studies on FTIR demonstrated probable bonding between the aceclofenac and mixed pluronic molecules. The DLS studies on mixed pluronic showed swelling of micellar diameter from 317.6 nm to 413.5 nm. Thermodynamic parameters of the above system revealed higher partition coefficient value for mixed pluronic and spontaneity in drug solubilisation. This study can be exploited to use a hydrophobic copolymeric micelle in mixed pluronic formulation for better drug solubilisation.

Therapeutic Applications of Curcumin in Diabetes: A Review and Perspective

Diabetes is a metabolic disease with multifactorial causes which requires lifelong drug therapy as well as lifestyle changes. There is now growing scientific evidence to support the effectiveness of the use of herbal supplements in the prevention and control of diabetes. Curcumin is one of the most studied bioactive components of traditional medicine, but its physicochemical characteristics are represented by low solubility, poor absorption, and low efficacy. Nanotechnology-based pharmaceutical formulations can help overcome the problems of reduced bioavailability of curcumin and increase its antidiabetic effects. The objectives of this review were to review the effects of nanocurcumin on DM and to search for databases such as PubMed/MEDLINE and ScienceDirect. The results showed that the antidiabetic activity of nanocurcumin is due to complex pharmacological mechanisms by reducing the characteristic hyperglycemia of DM. In light of these results, nanocurcumin may be considered as potential agent in the pharmacotherapeutic management of patients with diabetes.

γ-Cyclodextrin-based polypseudorotaxane hydrogels for ophthalmic delivery of flurbiprofen to treat anterior uveitis

Anterior uveitis is a sight-threatening inflammation inside the eyes. Conventional eye drops for anti-inflammatory therapy need to be administered frequently owing to the rapid elimination and corneal barrier. To address these issues, polypseudorotaxane hydrogels were developed by mixing Soluplus micelles (99.4 nm) and cyclodextrins solution. The optimized hydrogels exhibited shear-thinning and sustained release properties. The hydrogels exhibited higher transcorneal permeability coefficient (P_app, 1.84 folds) than that of drug solutions. Moreover, animal study indicated that the hydrogels significantly increased the precorneal retention (AUC, 21.2 folds) and intraocular bioavailability of flurbiprofen (AUC_{Aqueous humor}, 17.8 folds) in comparison with drug solutions. Importantly, the hydrogels obviously boosted anti-inflammatory efficacy in rabbit model of endotoxin-induced uveitis at a reduced administration frequency. Additionally, the safety of hydrogels was confirmed by cytotoxicity and ocular irritation studies. In all, the present study demonstrates a friendly non-invasive strategy based on γ-CD-based polypseudorotaxane hydrogels for ocular drug delivery.

Micelles in Cancer Therapy: An Update on Preclinical and Clinical Status

BACKGROUND

In the recent years, Micelles represent a promising carrier for the treatment and diagnosis of cancer. Architecturally, micelles are self-assembled nanosized colloidal aggregates prepared from amphiphilic surfactant with a hydrophobic core and hydrophilic shell. Such a composition makes them a potential carrier for delivery of hydrophobic anticancer drugs with in their core.

METHODS

Micelles have received increasing interest as an enhanced permeability and retention (EPR) targeted drug delivery systems for cancer treatment. Micelles can be modified to contribute various attractive properties, for instance, active targeting, stimuli-responsiveness. They have also proven their ability in drug targeting to tumor tissue, enhanced drug accumulation, drug stabilization, tissue penetration, prolong circulation, in vivo biocompatibility, biodegradability and reduced side effects. Micelles have displayed a vital role in multidrug delivery for cancer therapy.

RESULTS AND DISCUSSION

The aim of the present review is to provide an overview on the status of micellar nanoformulations for anticancer agents, including their pre-clinical and clinical researches. Emphasis is placed on presenting the newer strategies to enhance the therapeutic efficacy of anticancer drug at the target site. The type of co-polymers used and methods for the preparation of micelles are also highlighted in the paper.

Recent advances of nanotechnology in the diagnosis and therapy of triple-negative breast cancer (TNBC)

BACKGROUND

The development of advanced treatment of triple-negative breast cancer (TNBC) is the utmost need of an era. TNBC is recognized as the most aggressive, metastatic cancer and the leading cause of mortality in females worldwide. The lack of expression of triple receptors namely, estrogen, progesterone, and human epidermal receptor2 defined TNBC.

OBJECTIVE

The current review introduced the novel biomarkers such as miRNA and family, PD1, EGFR, VEGF, TILs, P53, AR and PI3K, etc. contributed significantly to the prognosis and diagnosis of TNBC. Once diagnosed the utilization advanced approaches available for TNBC because of the limitations of chemotherapy. Novel approaches include lipid-based (liposomes, SLN, NLC, and SNEDDS), polymer-based (micelle, nanoparticles, dendrimers, and quantum dots), advanced nanocarriers such as (exosomes, antibody and peptide-drug conjugates), carbon-based nanocarriers (Carbon nanotubes, and graphene oxide). Lipid-based delivery is used for excellent carriers for hydrophobic drugs, biocompatibility, and lesser systemic toxicities than chemotherapeutic agents. Polymer-based approaches are preferred over lipids for providing longer circulation time, nanosize, high loading efficiency, high linking; avoiding the expulsion of drugs, targeted action, diagnostic and biosensing abilities. Advanced approaches like exosomes, conjugated moieties are preferred over polymeric for possessing potency, high penetrability, biomarkers, and avoiding the toxicity of tissues. Carbon-based gained wide applicability for their unique properties like a versatile carrier, prognostic, diagnostic, sensing, photodynamic, and photothermal characteristics.

CONCLUSION

The survival rate can be increased by utilizing several kinds of biomarkers. The advanced approaches can also be significantly useful in the prognosis and theranostic of triple-negative breast cancer. One of the biggest successes in treating with nanotechnology-based approaches is the marked reduction of systemic toxicity with high therapeutic effectiveness compared with chemotherapy, surgery, etc. The requirements such as prompt diagnosis, longer circulation time, high efficiency, and high potency, can be fulfilled with these nanocarriers.

Recent Advances in the Local Drug Delivery Systems for Improvement of Anticancer Therapy

The conventional anticancer chemotherapies not only cause serious toxic effects, but also produce resistance in tumor cells exposed to long-term therapy. Usually, the killing of metastasized cancer cells requires long-term therapy with higher drug doses, because the cancer cells develop resistance due to the induction of poly-glycoproteins (P-gps) that act as a transmembrane efflux pump to transport drugs out of the cells. During the last few decades, scientists have been exploring new anticancer drug delivery systems such as microencapsulation, hydrogels, and nanotubes to improve bioavailability, reduce drug-dose requirement, decrease multiple drug resistance, and to save normal cells as non-specific targets. Hopefully, the development of novel drug delivery vehicles (nanotubes, liposomes, supramolecules, hydrogels, and micelles) will assist to deliver drug molecules at the specific target site and reduce the undesirable side effects of anticancer therapies in humans. Nanoparticles and lipid formulations are also designed to deliver small drug payload at the desired tumor cell sites for their anticancer actions. This review will focus on the recent advances in the drug delivery systems, and their application in treating different cancer types in humans.

Thermoresponsive polymeric dexamethasone prodrug for arthritis pain

Intra-articular (IA) glucocorticoids (GC) are commonly used for clinical management of both osteoarthritis and rheumatoid arthritis, but their efficacy is limited by the relatively short duration of action and associated side effects. To provide sustained efficacy and to improve the safety of GCs, we previously developed a N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-based dexamethasone (Dex) prodrug. Serendipitously, we discovered that, by increasing the Dex content of the prodrug to unusually high levels, the aqueous solution of the polymeric prodrug becomes thermoresponsive, transitioning from a free-flowing liquid at 4 °C to a hydrogel at 30 °C or greater. Upon IA injection, the prodrug solution forms a hydrogel (ProGel-Dex) that is retained in the joint for more than 1 month, where it undergoes gradual dissolution, releasing the water-soluble polymeric prodrug. The released prodrug is swiftly internalized and intracellularly processed by phagocytic synoviocytes to release free Dex, resulting in sustained amelioration of joint inflammation and pain in rodent models of inflammatory arthritis and osteoarthritis. The low molecular weight (6.8 kDa) of the ProGel-Dex ensures rapid renal clearance once it escapes the joint, limiting systemic GC exposure and risk of potential off-target side effects. The present study illustrates the translational potential of ProGel-Dex as a potent opioid-sparing, locally delivered adjuvant analgesic for sustained clinical management of arthritis pain and inflammation. Importantly, the observed thermoresponsive properties of the prodrug establishes ProGel as a platform technology for the local delivery of a broad spectrum of therapeutic agents to treat a diverse array of pathological conditions.

A comprehensive review on possibilities of treating psoriasis using dermal cyclosporine

Psoriasis is an autoimmune, chronic proliferative, inflammatory skin disease with high comorbidity. Psoriasis is not a curable disease; it can only be managed. Cyclosporine A (CyA) is one of the FDA-approved immunosuppressant drug used in severe Psoriasis. Till date only oral route is used for its administration. Administration of CyA by this route causes serious side effects such as hypertension and renal toxicity. Due to these side effects, a number of researches have been done and taking place in the current times for the dermal delivery of CyA for the management of psoriasis. Dermal delivery of CyA is not an easy task because of its physiochemical properties like high molecular weight, lipophilicity and resistance offered by stratum corneum (SC). Because of the above problems in the dermal delivery a number of new approaches such as nanolipid carriers, microemulsion, liposomes, niosomes etc. are explored. To those deep findings for psoriasis management with dermal delivery of CyA have not been discussed. This comprehensive review includes all the studies, advancements and their critical findings which took place in the recent times for the dermal delivery of CyA and along with the suitable modification needed for the efficient dermal delivery of CyA are also suggested.

Preparation and Characterization of Palladium Derivate-Loaded Micelle Formulation in Vitro as an Innovative Therapy Option against Non-Small Cell Lung Cancer Cells

Nanoparticles have been used in cancer treatments to target tumor and reduce side effects. In this study, we aimed to increase the effectiveness of palladium(II) complex [PdCl(terpy)](sac) ⋅ 2H₂ O, which previously showed anticancer potential, by preparing the nanoparticle formulation. An inhalable micellar dispersion containing a palladium(II) complex (PdNP) was prepared and its physicochemical characteristics were evaluated using in vitro tests. Morphology, size and surface charges of particle and loading/encapsulation efficiency of PdNP were analyzed by scanning electron microscopy, zeta sizer and inductively coupled plasma mass spectrometry while aerosol properties of PdNP were measured by the next generation impactor. A549 and H1299 non-small lung cancer cell types were used for cytotoxicity using SRB and ATP assays. Fluorescent staining and M30 antigen assay were carried out for cell death evaluation. Apoptosis was confirmed by flow cytometry analyses. SEM, particle size, and zeta potential results showed the particles have inhalable properties. The amount of the palladium(II) complex loaded into the particles was quantified which indicated high encapsulation efficiencies (97 %). The micellar dispersion expected to reach the alveolar region and the brachial region was determined 35 % and 47 %, respectively. PdNP showed an anti-growth effect by increasing reactive oxygen species that is followed by the induction of mitochondria-dependent apoptosis that is evidenced by pyknotic nuclei and M30 antigen level increments and disruption of polarization of membrane in mitochondria (Δψm). The results show that PdNP might be a promising inhalable novel complex to be used in non-small cell lung cancer, which warrants animal studies in further.

Continuous processing of paclitaxel polymeric micelles

A continuous polymeric micelle processing platform was successfully developed, which eliminated batch-to-batch variation in critical quality attributes (for example, size and polydispersity that are typically associated with batch processing). A continuous precipitation process was achieved via coaxial turbulent jet in co-flow technology allowing precise control of particle size with average particle size in the range 15 to 70 nm and low polydispersity. Critical relationships between material attributes (e.g., block copolymer design), process parameters (e.g., polymer concentration, organic to aqueous flow rate ratios, and temperature), and critical quality attributes (e.g., size and polydispersity) of the polymeric micelles were realized via multiple designs of experiments studies. Both polymer molecular weight and concentration were shown to influence the micelle polydispersity index. Notably, higher molecular weight polymer required higher processing temperatures to produce monodispersed particles and were generally of larger size. Using optimized conditions, paclitaxel polymeric micelles that are qualitatively and quantitatively equivalent to commercial Genexol PM were produced, exhibiting comparable quality attributes including particle size, size distribution, morphology, drug loading, release characteristics, and stability. Lastly, a dynamic light scattering method was adapted to determine the critical micelle concentration and aggregation number of the block copolymers, providing useful information about the raw material.

Nanoengineering Branched Star Polymer-Based Formulations: Scope, Strategies, and Advances

Soft nanoparticles continue to offer a promising platform for the encapsulation and controlled delivery of poorly water-soluble drugs and help enhance their bioavailability at targeted sites. Linear amphiphilic block copolymers are the most extensively investigated in formulating delivery vehicles. However, more recently, there has been increasing interest in utilizing branched macromolecules for nanomedicine, as these have been shown to lower critical micelle concentrations, form particles of smaller dimensions, facilitate the inclusion of varied compositions and function-based entities, as well as provide prolonged and sustained release of cargo. In this review, it is aimed to discuss some of the key variables that are studied in tailoring branched architecture-based assemblies, and their influence on drug loading and delivery. By understanding structure-property relationships in these formulations, one can better design branched star polymers with suitable characteristics for efficient therapeutic interventions. The role played by polymer composition, chain architecture, crosslinking, stereocomplexation, compatibility between polymers and drugs, drug/polymer concentrations, and self-assembly methods in their performance as nanocarriers is highlighted.

Drug Delivery to the Bone Microenvironment Mediated by Exosomes: An Axiom or Enigma

The increasing incidence of bone-related disorders is causing a burden on the clinical scenario. Even though bone is one of the tissues that possess tremendous regenerative potential, certain bone anomalies need therapeutic intervention through appropriate delivery of a drug. Among several nanosystems and biologics that offer the potential to contribute towards bone healing, the exosomes from the class of extracellular vesicles are outstanding. Exosomes are extracellular nanovesicles that, apart from the various advantages, are standing out of the crowd for their ability to conduct cellular communication. The internal cargo of the exosomes is leading to its potential use in therapeutics. Exosomes are being unraveled in terms of the mechanism as well as application in targeting various diseases and tissues. Through this review, we have tried to understand and review all that is already established and the gap areas that still exist in utilizing them as drug delivery vehicles targeting the bone. The review highlights the potential of the exosomes towards their contribution to the drug delivery scenario in the bone microenvironment. A comparison of the pros and cons of exosomes with other prevalent drug delivery systems is also done. A section on the patents that have been generated so far from this field is included.

Advances in Nano-Enabled Platforms for the Treatment of Depression

Nanotechnology has aided in the advancement of drug delivery for the treatment of several neurological disorders including depression. Depression is a relatively common mental disorder which is characterized by a severe imbalance of neurotransmitters. Several current therapeutic regimens against depression display drawbacks which include low bioavailability, delayed therapeutic outcome, undesirable side effects and drug toxicity due to high doses. The blood–brain barrier limits the entry of the drugs into the brain matrix, resulting in low bioavailability and tissue damage due to drug accumulation. Due to their size and physico-chemical properties, nanotechnological drug delivery systems present a promising strategy to enhance the delivery of nanomedicines into the brain matrix, thereby improving bioavailability and limiting toxicity. Furthermore, ligand-complexed nanocarriers can improve drug specificity and antidepressant efficacy and reduce drug toxicity. Biopolymers and nanocarriers can also be employed to enhance controlled drug release and reduce the hepatic first-pass effect, hence reducing the dosing frequency. This manuscript reviews recent advances in different biopolymers, such as polysaccharides and other nanocarriers, for targeted antidepressant drug delivery to the brain. It probes nano-based strategies that can be employed to enhance the therapeutic efficacy of antidepressants through the oral, intranasal, and parenteral routes of administration.

Harnessing amphiphilic polymeric micelles for diagnostic and therapeutic applications: Breakthroughs and bottlenecks

Amphiphilic block copolymers are widely utilized in the design of formulations owing to their unique physicochemical properties, flexible structures and functional chemistry. Amphiphilic polymeric micelles (APMs) formed from such copolymers have gained attention of the drug delivery scientists in past few decades for enhancing the bioavailability of lipophilic drugs, molecular targeting, sustained release, stimuli-responsive properties, enhanced therapeutic efficacy and reducing drug associated toxicity. Their properties including ease of surface modification, high surface area, small size, and enhanced permeation as well as retention (EPR) effect are mainly responsible for their utilization in the diagnosis and therapy of various diseases. However, some of the challenges associated with their use are premature drug release, low drug loading capacity, scale-up issues and their poor stability that need to be addressed for their wider clinical utility and commercialization. This review describes comprehensively their physicochemical properties, various methods of preparation, limitations followed by approaches employed for the development of optimized APMs, the impact of each preparation technique on the physicochemical properties of the resulting APMs as well as various biomedical applications of APMs. Based on the current scenario of their use in treatment and diagnosis of diseases, the directions in which future studies need to be carried out to explore their full potential are also discussed.

Denture-Soaking Solution Containing Piper betle Extract-Loaded Polymeric Micelles; Inhibition of Candida albicans, Clinical Study, and Effects on Denture Base Resin

Candida albicans is a common overgrowth in people wearing dentures. Long-term use of antifungal chemicals carries a risk of toxic side effects. This study focused on the edible Piper betle extract because of its safety. The broth dilution method was applied for antifungal determination of the ethyl acetate fractionated extract (fEA) and fEA-loaded polymeric micelles (PMF). The PMF was prepared by thin-film hydration using poloxamer 407 as a polymer base. The results found that the weight ratio of fEA to polymer is the main factor to obtain PMF system as a clear solution, nanoparticle sizes, narrow size distribution, negative zeta potential, and high entrapment efficiency. The activity of PMF against C. albicans is significantly higher than fEA alone, with a minimum fungicidal concentration of 1.5 mg/mL. PMF from 1:3 ratio of fEA to polymer is used to develop a denture-soaking solution contained 1.5 mg fEA/mL (PMFS). A clinical study on dentures of 15 volunteers demonstrated an 86.1 ± 9.2% reduction of C. albicans after soaking the dentures in PMFS daily for 14 days. Interestingly, PMFS did not change the hardness and roughness of the denture base resins. The developed PMFS may serve as a potential natural denture-soaking solution against candidiasis in denture wearers.

Recent advances in peptide-targeted micelleplexes: Current developments and future perspectives

The decoding of the human genome revolutionized the understanding of how genetics influence the interplay between health and disease, in a multidisciplinary perspective. Thus, the development of exogenous nucleic acids-based therapies has increased to overcome hereditary or acquired genetic-associated diseases. Gene drug delivery using non-viral systems, for instance micelleplexes, have been recognized as promising options for gene-target therapies. Micelleplexes are core-shell structures, at a nanometric scale, designed using amphiphilic block copolymers. These can self-assemble in an aqueous medium, leading to the formation of a hydrophilic and positively charged corona - that can transport nucleic acids, - and a hydrophobic core - which can transport poor water-soluble drugs. However, the performance of these types of carriers usually is hindered by several in vivo barriers. Fortunately, due to a significant amount of research, strategies to overcome these shortcomings emerged. With a wide range of structural features, good stability against proteolytic degradation, affordable characteristic, easy synthesis, low immunogenicity, among other advantages, peptides have increasingly gained popularity as target ligands for non-viral carriers. Hence, this review addresses the use of peptides with micelleplexes illustrating, through the analysis of in vitro and in vivo studies, the potential and future perspectives of this combination.