Tween 80-Based Self-Assembled Mixed Micelles Boost Valsartan Transdermal Delivery

Valsartan (Val) is an important antihypertensive medication with poor absorption and low oral bioavailability. These constraints are due to its poor solubility and dissolution rate. The purpose of this study was to optimize a mixed micelle system for the transdermal delivery of Val in order to improve its therapeutic performance by providing prolonged uniform drug levels while minimizing drug side effects. Thin-film hydration and micro-phase separation were used to produce Val-loaded mixed micelle systems. A variety of factors, including the surfactant type and drug-to-surfactant ratio, were optimized to produce micelles with a low size and high Val entrapment efficiency (EE). The size, polydispersity index (PDI), zeta potential, and drug EE of the prepared micelles were all measured. The in vitro drug release profiles were assessed using dialysis bags, and the permeation through abdominal rat skin was assessed using a Franz diffusion cell. All formulations had high EE levels exceeding 90% and low particle charges. The micellar sizes ranged from 107.6 to 191.7 nm, with average PDI values of 0.3. The in vitro release demonstrated a uniform slow rate that lasted one week with varying extents. F7 demonstrated a significant (p < 0.01) transdermal efflux of 68.84 ± 3.96 µg/cm2/h through rat skin when compared to the control. As a result, the enhancement factor was 16.57. In summary, Val-loaded mixed micelles were successfully prepared using two simple methods with high reproducibility, and extensive transdermal delivery was demonstrated in the absence of any aggressive skin-modifying enhancers.

Cinnamyl-Modified Polyglycidol/Poly(ε-Caprolactone) Block Copolymer Nanocarriers for Enhanced Encapsulation and Prolonged Release of Cannabidiol

The present study describes the development of novel block copolymer nanocarriers of the phytocannabinoid cannabidiol (CBD), designed to enhance the solubility of the drug in water while achieving high encapsulation efficiency and prolonged drug release. Firstly, a well-defined amphiphilic block copolymer consisting of two outer hydrophilic polyglycidol (PG) blocks and a middle hydrophobic block of poly(ε-caprolactone) bearing pendant cinnamyl moieties (P(CyCL-co-CL)) were synthesized by the click coupling reaction of PG-monoalkyne and P(CyCL-co-CL)-diazide functional macroreagents. A non-modified polyglycidol/poly(ε-caprolactone) amphiphilic block copolymer was obtained as a referent system. Micellar carriers based on the two block copolymers were formed via the solvent evaporation method and loaded with CBD following two different protocols-loading during micelle formation and loading into preformed micelles. The key parameters/characteristics of blank and CBD-loaded micelles such as size, size distribution, zeta potential, molar mass, critical micelle concentration, morphology, and encapsulation efficiency were determined by using dynamic and static multiangle and electrophoretic light scattering, transmission electron microscopy, and atomic force microscopy. Embedding CBD into the micellar carriers affected their hydrodynamic radii to some extent, while the spherical morphology of particles was not changed. The nanoformulation based on the copolymer bearing cinnamyl moieties possessed significantly higher encapsulation efficiency and a slower rate of drug release than the non-modified copolymer. The comparative assessment of the antiproliferative effect of micellar CBD vs. the free drug against the acute myeloid leukemia-derived HL-60 cell line and Sezary Syndrome HUT-78 demonstrated that the newly developed systems have pronounced antitumor activity.

Structure-Based Varieties of Polymeric Nanocarriers and Influences of Their Physicochemical Properties on Drug Delivery Profiles

Carriers are equally important as drugs. They can substantially improve bioavailability of cargos and safeguard healthy cells from toxic effects of certain therapeutics. Recently, polymeric nanocarriers (PNCs) have achieved significant success in delivering drugs not only to cells but also to subcellular organelles. Variety of natural sources, availability of different synthetic routes, versatile molecular architectures, exploitable physicochemical properties, biocompatibility, and biodegradability have presented polymers as one of the most desired materials for nanocarrier design. Recent innovative concepts and advances in PNC-associated nanotechnology are providing unprecedented opportunities to engineer nanocarriers and their functions. The efficiency of therapeutic loading has got considerably increased. Structural design-based varieties of PNCs are widely employed for the delivery of small therapeutic molecules to genes, and proteins. PNCs have gained ever-increasing attention and certainly paves the way to develop advanced nanomedicines. This article presents a comprehensive investigation of structural design-based varieties of PNCs and the influences of their physicochemical properties on drug delivery profiles with perspectives highlighting the inevitability of incorporating both the multi-stimuli-responsive and multi-drug delivery properties in a single carrier to design intelligent PNCs as new and emerging research directions in this rapidly developing area.

Modeling of Anti-cancer Drug Release Kinetics from Liposomes and Micelles: A review

Nanocarriers, such as liposomes and micelles, were developed to enhance the delivery of therapeutic drugs to malignant tissues. Internal or external stimuli can be applied to achieve spatiotemporal controlled release from these carriers. This will result in enhancing their therapeutic efficacy while reducing toxicity. Mathematical modeling is used to simulate drug release from nanocarriers; this will facilitate and optimize the development and design of desirable nanocarriers in a systematic manner, rather than a trial-and-error approach. This review summarizes nine mathematical models often used to simulate drug release from nanocarriers and reviews studies which employed these models to simulate drug release from conventional as well as temperature-, pH-, and ultrasound-triggered micelles and liposomes.

A novel self-assembled micelles based on stearic acid modified schizophyllan for efficient delivery of paclitaxel

This study was aimed to design a novel amphiphilic carrier based on schizophyllan (SPG) exopolysacharide for drug delivery. Stearic acid (SA) was used for the esterification of SPG with two degrees of substitutions (SA-SPG0.5 and SA-SPG1). The H NMR and FTIR spectroscopies verified the succesfull esterification of SPG. The polymeric micelles easily self-assembled into nanomicelles by ultrasound method. Fluorescence spectroscopy showed that the critical micelle concentrations (CMCs) of SA-SPG0.5 and SA-SPG1 micelles were 0.068 mg/mL and 0.027 mg/mL, respectively. DLS analyses showed that nanomicelles were ranged from 156 to 175 nm. SEM and TEM images showed that nanomicelles were mostly spherical. Paclitaxel (PTX) as a drug model was successfully loaded into SA-SPG nanomicelles with three different drug/polymer weight ratios of 0.1, 0.2 and 0.3. The highest encapsulation efficiency (75 %) was obtained when the PTX/SA-SPG weight ratio was 0.1. The in vitro release of PTX from SA-SPG micelles represented the sustained release profile over 144 h. MTT assay showed that the PTX-loaded SA-SPG nanomicelles had the higher cytotoxicity against MCF-7 cells than free PTX. These results revealed that the synthesized SA-SPG nanomicelles had a promising potential as a new carrier for efficient delivery of hydrophobic drugs.

Supramolecular Loading of a Broad Spectrum of Molecular Guests In Hyperbranched Polytriazole Nanoparticles with Cores Containing Multiple Functional Groups

This study evaluated the supramolecular properties of a new family of water-soluble hyperbranched polytriazoles that have a unimolecular micelle structure. Two new, structurally related hyperbranched polymers (HBPa and HBPn), with the same size (D_h = 11 nm) and core-shell architecture, were prepared and found to act as nanoscale hosts for a broad spectrum of molecular guests. The globular-shaped hyperbranched polymers were synthesized by a straightforward one-pot polymerization method that permits easy synthetic control of the multiple functional groups within the core. Surrounding the core is a shell of polyethylene glycol chains that promotes solubility in pH 7.4 buffer solution and inhibits self-aggregation of the nanoparticles. The core of HBPa, containing a mixture of anionic carboxylate groups and 1,2,3-triazole rings, could be loaded with cationic hydrophilic (i.e., propidium iodide) or partially hydrophobic (i.e., Hoechst 33342) dyes or drugs, including a binary dye/drug pair (i.e., indocyanine green/mitoxantrone). The core of HBPn, containing a mixture of uncharged 2-pentanone chains and 1,2,3-triazole rings, could be loaded with uncharged and very hydrophobic dyes (i.e., Nile Red) or drugs. Improved aqueous solubility of camptothecin was achieved 10-fold from 8.4 to 75 ng/mL. Additionally, cell toxicity studies showed that HBPn was able to release the camptothecin drug inside A549 cancer cells resulting in increased cell death. Taken together, the results suggest that this new family of water-soluble hyperbranched polytriazoles could be broadly useful as nanocarriers for various applications in therapy, imaging, or a combination of the two (theranostics).

Stimuli-responsive DOX release behavior of cross-linked poly(acrylic acid) nanoparticles

Cross-linked poly(acrylic acid) nanoparticles were synthesized via distillation precipitation polymerization of acrylic acid and ethylene glycol dimethacrylate withdifferent molar ratios. Spherical nanoparticles with diameters between 75 and 122 nm were synthesized and exhibited temperature and pH-responsive behaviors. However, this behavior was less pronounced for samples with higher cross-linking degrees. The potential of all nanoparticles as carriers for controlled release of doxorubicin (DOX) anti-cancer drug was examined at pH values of 1.2, 5.3 and 7.4. An obvious alleviation in burst release behavior and the amount of cumulative drug release was seen for all nanoparticles as the pH of the medium and the cross-linking degree of nanoparticle increased. Also kinetics of drug release was studied using mathematical models of zero-order, first-order, Higuchi, Korsmeyer-Peppas and Hixson-Crowell, where Higuchi and Korsmeyer-Peppas models best defined the kinetics of drug release.

Amphiphilic Block Copolymer Poly (Acrylic Acid)-B-Polycaprolactone as a Novel pH-sensitive Nanocarrier for Anti-Cancer Drugs Delivery: In-vitro and In-vivo Evaluation

Gambogenic acid (GNA) has been demonstrated with outstanding antitumor activity as a potential antitumor drug in recent years. However, the low solubility and deficient bioavailability of GNA seriously hinder its practical application in the clinic area. In this study, a novel amphiphilic block copolymer, poly (acrylic acid)-b-polycaprolactone (PAA-b-PCL) is prepared and assembled into pH-responsive polymeric micelles (PMs) as one mold of drug delivery system (DDS) with unique properties. Relevant investigation on PMs exhibits excellent carrying potential and pH-dependent release performance for GNA. The drug loading capacity (DLC) and drug loading efficiency (DLE) for GNA-loaded PMs can be achieved as high as 15.20 ± 0.07% and 83.67 ± 0.49%, respectively. The in vitro experiments indicate that the GNA releasing time, cytotoxicity, and cellular uptake are significantly enhanced. Especially, the peak concentration (Cmax) and area under the curve (AUC) are promoted sharply in the GNA-loaded PMs concentration-time curve. This study not only provides a novel way to widen the application of anticancer GNA in the future, but also extends the potential of stimuli-responsive copolymers to biomedical applications.

Stimuli Responsive Polymeric Systems for Cancer Therapy

Nanoscale polymers systems have dominated the revolution of drug delivery advancement. Their potential in the fight against cancer is unrivalled with other technologies. Their functionality increase, targeting ability and stimuli responsive nature have led to a major boom in research focus. This review article concentrates on the use of these smart polymers in cancer therapy. Nanotechnologies have shown potential as drug carriers leading to increased drug efficacy and penetration. Multifunctional smart carriers which can release their payload upon an external or internal trigger such as pH or temperature are proving to be major frontrunners in the development of effective strategies to overcome this disease with minimal patient side effects.

Investigation of different core-shell toward Janus morphologies by variation of surfactant and feeding composition: A study on the kinetics of DOX release

Composite particles with two individual hydrophilic parts were synthesized via seeded emulsion polymerization. As first part, nearly-monodisperse ethylene glycol dimethacrylate (EGDMA)-crosslinked poly(acrylic acid) (PAA) particles were synthesized by distillation precipitation polymerization (DPP). These particles were used as seeds in emulsion polymerization of 2-(dimethylamino)ethyl methacrylate (DMAEMA). Effects of type of surfactant, monomers/seed weight ratio and amount of shell crosslinker on the synthesized composite particles' morphology were studied. Different morphologies consisting of core-shell, Janus type, raspberry-like and porous core-shell structures were investigated by variations of polymerization parameters. Different structures were chosen as drug carriers and subjected to DOX loading and release system. Results showed that amount of drug loading and extent of release were strongly dependent on the structure of carriers whereas for all carriers, DOX was released more rapid. Kinetics of release was evaluated by different mathematical models to investigate the release mechanism through composite particles. Results showed that only Korsmeyer-Peppas model fitted the drug release data and other ones were inappropriate in this field.

Synthesis and characterization of poly(propylene imine)-dendrimer-grafted gold nanoparticles as nanocarriers of doxorubicin

The aim of current work is synthesis 4th-generation-poly(propylene imine) (PPI)-dendrimer modified gold nanoparticles (Au-G4A) as nanocarriers for doxorubicin (DOX) and studying in vitro drug release kinetics from nanocarriers into different media. Accordingly, AuNPs were synthesized by reduction of chloroauric acid (HAuCl₄) aqueous solution with trisodium citrate and modified with cysteamine to obtain amine-functionalized (Au-NH₂) nanoparticles. Au-NH₂ nanoparticles were used as multifunctional cores and participated in Michael addition of acrylonitrile and reduction process by lithium aluminum hydride (LAH) to synthesize Au-G4A nanoparticles. Also, peripheral primary amine groups of Au-G4A were conjugated with folic acid (FA) (Au-G4F) to study the bioconjugation effect on drug release behavior of nanostructures. Ultraviolet spectroscopy (UV-vis), atomic force microscopy (AFM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and thermal gravimetric analysis (TGA) were used to approve the synthesis of different nanostructures. Finally, Au-G4A and Au-G4F samples were loaded with DOX and exposed to environments with different pH values to examine the release properties of nanostructures. Also, drug release kinetics was investigated by fitting of experimental data with different release models. As a result, synthesized dendritic structures showed Higuchi and Korsmeyer-Peppas models release behavior due to better solubility of drug in release media with respect to dendrimer cavities and drug release through polymeric matrix respectively.

Mercaptan acids modified amphiphilic copolymers for efficient loading and release of doxorubicin

In this paper, four different kinds of mercaptan acids modified amphiphilic copolymers mPEG-b-PATMC-g-SRCOOH (R=CH₂, CH₂CH₂, (CH₂)₁₀ and CH(COOH)CH₂) were successfully synthesized by thiol-ene "click" reaction between pendent carbon-carbon double bonds of PEG-b-PATMC and thiol groups of thioglycolic acid, 3-mercaptopropionic acid, 11-mercaptoundecanoic acid or 2-mercaptosuccinic acid. DLS and TEM measurements showed that all the mPEG-b-PATMC-g-SRCOOH copolymers could self-assemble to form micelles which dispersed in spherical shape with nano-size before and after DOX loading. The positively-charged DOX could effectively load into copolymer micelles via synergistic hydrophobic and electrostatic interactions. All DOX-loaded mPEG-b-PATMC-g-SRCOOH micelles displayed sustained drug release behavior without an initial burst which could be further adjusted by the conditions of ionic strength and pH. Especially in the case of mPEG-b-PATMC-g-S(CH₂)₁₀COOH (P3) micelles, the suitable hydrophobility and charge density were not only beneficial to improve the DOX-loading efficiency, they were also good for obtaining smaller particle size, higher micelle stability and more timely drug delivery. Confocal laser scanning microscopy (CLSM) and MTT assays further demonstrated efficient cellular uptake of DOX delivered by mPEG-b-PATMC-g-SRCOOH micelles and potent cytotoxic activity against cancer cells.