Development of Blueberry-Derived Extracellular Nanovesicles for Immunomodulatory Therapy

Over the past decade, there has been a significant expansion in the development of plant-derived extracellular nanovesicles (EVs) as an effective drug delivery system for precision therapy. However, the lack of effective methods for the isolation and characterization of plant EVs hampers progress in the field. To solve a challenge related to systemic separation and characterization in the plant-derived EV field, herein, we report the development of a simple 3D inner filter-based method that allows the extraction of apoplastic fluid (AF) from blueberry, facilitating EV isolation as well as effective downstream applications. Class I chitinase (PR-3) was found in blueberry-derived EVs (BENVs). As Class I chitinase is expressed in a wide range of plants, it could serve as a universal marker for plant-derived EVs. Significantly, the BENVs exhibit not only higher drug loading capacity than that reported for other EVs but also possess the ability to modulate the release of the proinflammatory cytokine IL-8 and total glutathione in response to oxidative stress. Therefore, the BENV is a promising edible multifunctional nano-bio-platform for future immunomodulatory therapies.

The Use of Natural Materials in Film Coating for Controlled Oral Drug Release

BACKGROUND

Although synthetic materials have been used in film coating processes for drug delivery for many years, substantial studies on natural materials have also been conducted because of their biodegradable and unique properties.

METHODS

Because of the ability to form and modify films for controlled oral drug delivery, increasing attention has been shown to these materials in the design of film coating systems in recent research.

RESULTS

This review aims to provide an overview of natural materials focusing on film coating for oral delivery, specifically in terms of their classification and their combinations in film coating formulations for adjusting the desired properties for controlled drug delivery.

CONCLUSIONS

Discussing natural materials and their potential applications in film coating would benefit the optimization of processes and strategies for future utilization.

A Detailed Protein-SELEX Protocol Allowing Visual Assessments of Individual Steps for a High Success Rate

As a nucleic acid alternative to traditional antibody, aptamer holds great potential in various fields of biology and medicine such as targeted gene therapy, drug delivery, bio-sensing, and laboratory medicine. Over the past decades, the conventional Systematic Evolution of Ligands by Exponential Enrichment (SELEX) method has undergone dramatic modifications and improvements owing to developments in material sciences and analytical techniques. However, many of the recently developed strategies either require complex materials and instruments or suffer from low efficiency and high failure rates in the selection of desired aptamers. Accordingly, the development of aptamers against new or novel targets is still a major obstacle for aptamer-based research and application. Here, an improved protein-SELEX procedure is presented for simplified and highly efficient isolation of aptamers against protein targets. Approaches are described that ensure a high success rate in aptamer selection by simplifying polymerase chain reaction procedures, introducing denature gel, utilizing an electro-elution-based single-stranded DNA separation strategy, as well as an enzyme-linked immunosorbent assay-based highly sensitive binding assay. In addition, a simplified sample preparation method for MiSeq-based next-generation sequencing is also introduced. While a recombinant protein as a bait protein for SELEX is discussed here, this protocol will also be invaluable for researchers wishing to develop aptamers against targets other than proteins such as small molecules, lipids, carbohydrates, cells, and micro-organisms for future gene therapy and/or diagnostics.

Development of conjugate-by-conjugate structured nanoparticles for oral delivery of docetaxel

In the current study, we developed interpolymer-complex structures composed of hydroxypropyl methylcellulose (HPMC) and chitosan knitted with d-α-tocopherol polyethylene glycol succinate (TPGS) to establish oral nanoparticle delivery systems that could keep the drug dose from releasing into the gastrointestinal tract for at least 6 h. Two kinds of nanoparticle formations based on the so-called conjugate-by-conjugate strategy were introduced in the study. In the first conjugate-by-conjugate structured nanoparticle formation, TPGS was conjugated with an HPMC-chitosan conjugate, followed by the drug loading process. In the second approach, the drug was loaded with TPGS directly and subsequently conjugated with the HPMC-chitosan conjugate. Beneficially, polyvinyl alcohol could act not only as a stabilizing agent but also as a crosslinking agent for the nanoparticles. This study created newly modified structures of HPMC and chitosan, altering their physicochemical properties that could then retard drug release. The nanoparticles were cytotoxic towards MDA-MB-231 breast cancer cells when docetaxel was loaded in the nanoparticles, particularly the nanoparticles produced in the second approach, demonstrating their ability to kill cancerous cells and their potential for further applications in cancer therapy. Additionally, when Caco-2 cells were used as an absorption model in a transport study, the nanoparticles in the second approach showed their capacity to increase drug permeability across the monolayers of Caco-2 cells compared to the free-drug solution. This study also illustrated the enhanced uptake of the nanoparticles by the Caco-2 cells, implying enhanced absorption through the intestine. Therefore, these oral nanoparticles can be considered for delivery systems of agents that are sensitive to the gastrointestinal tract so that they can be transported across the epithelial cells to the bloodstream to deliver the loading cargo at an optimal concentration.

Investigation of Crystallization and Salt Formation of Poorly Water-Soluble Telmisartan for Enhanced Solubility

The crystal changes and salt formation of poorly water-soluble telmisartan (TEL) in various solvents were investigated for enhanced solubility, stability and crystallinity. Polymorphic behaviors of TEL were characterized by dispersing in distilled water, acetone, acetonitrile, DMSO, or ethanol using Method I: without heat and then dried under vacuum at room temperature; and Method II: with heat below boiling temperature, cooled at 5 °C, and then dried under vacuum at 40 °C. For salt formation (Method III), the following four powdered mixtures were prepared by dispersing in solution of hydrochloric acid (HCl) (pH 1.2), TEL/HCl; in simulated gastric fluid (pH 1.2 buffer), TEL/simulated gastric fluid (SGF); in intestinal fluid (pH 6.8 buffer), TEL/simulated intestinal fluid (SIF); or in NaOH (pH 6.8), TEL/NaOH, respectively, and then dried under a vacuum at room temperature. The structures of powdered mixtures were then studied using a field emission scanning electron microscope (FESEM), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), FTIR, ¹H nuclear magnetic resonance (¹H-NMR), and LC⁻MS. The solubility of TEL in powdered forms was performed in pH 6.8, pH 1.2, and distilled water. No polymorphic behaviors of TEL were observed in various solvents as characterized by FESEM, DSC, PXRD, and FTIR. However, the structural changes of powdered mixtures obtained from Method III were observed due to the formation of salt form. Moreover, the solubility of salt form (TEL/HCl) was highly increased as compared with pure TEL. There were no significant changes of TEL/HCl compared with TEL in the content assay, PXRD, DSC, and FTIR during stressed storage conditions at 40 °C/75% relative humidity (RH) for 4 weeks under the closed package condition. Therefore, the present study suggests the new approach for the enhanced stability and solubility of a poorly water-soluble drug via salt form.

Nano-Precipitation: Preparation and Application in the Field of Pharmacy

Over the last 30 years, nanoparticle-based medicine has received tremendous attention due to its advances with smart therapeutics and less toxicity. Few nanomedicine products have been approved for commercial use in the clinic (such as Doxil(®), Ambraxane(®)..). Nanomedicine research is still at its early stage and the preparation of nanoparticles must be carefully considered. Systems involving further increased supersaturation, either via solvent evaporation, temperature reduction or anti-solvent mixture, were suggested to be capable of inducing nanoprecipitation (NPT). Since this technique is straight-forward, fast and easy to duplicate in practice, it is highly preferred and recommended. In this review, the process of NTP was described and discussed in detail. Factors that affect the encapsulation efficiency, the nanoparticle size, the morphology and the stability of nanoparticles prepared by NTP were described. This process is one of the most preferable processes for preparing solid nano-protein due to their elegant techniques that preserve the bioactivity of proteins. Although the production of nanoparticles by this process has not been applied in the pharmaceutical industry due to the organic solvent issue, the production equipment for large-scale has been marketed.

Microemulsion-Based Mucoadhesive Buccal Wafers: Wafer Formation, In Vitro Release, and Ex Vivo Evaluation

Microemulsion has the potentials to enhance dissolution as well as facilitate absorption and permeation of poorly water-soluble drugs through biological membranes. However, its application to govern a controlled release buccal delivery for local treatment has not been discovered. The aim of this study is to develop microemulsion-based mucoadhesive wafers for buccal delivery based on an incorporation of the microemulsion with mucoadhesive agents and mannitol. Ratio of oil to surfactant to water in the microemulsion significantly impacted quality of the wafers. Furthermore, the combination of carbopol and mannitol played a key role in forming the desired buccal wafers. The addition of an extra 50% of water to the formulation was suitable for wafer formation by freeze-drying, which affected the appearance and distribution of carbopol in the wafers. The amount of carbopol was critical for the enhancement of mucoadhesive properties and the sustained drug release patterns. Release study presented a significant improvement of the drug release profile following sustained release for 6 h. Ex vivo mucoadhesive studies provided decisive evidence to the increased retention time of wafers along with the increased carbopol content. The success of this study indicates an encouraging strategy to formulate a controlled drug delivery system by incorporating microemulsions into mucoadhesive wafers.

Transforming doxorubicin into a cancer stem cell killer via EpCAM aptamer-mediated delivery

Chemotherapy-resistant cancer stem cells (CSCs) are a major obstacle to the effective treatment of many forms of cancer. To overcome CSC chemo-resistance, we developed a novel system by conjugating a CSC-targeting EpCAM aptamer with doxorubicin (Apt-DOX) to eliminate CSCs. Incubation of Apt-DOX with colorectal cancer cells resulted in high concentration and prolonged retention of DOX in the nuclei. Treatment of tumour-bearing xenograft mice with Apt-DOX resulted in at least 3-fold more inhibition of tumour growth and longer survival as well as a 30-fold lower frequency of CSC and a prolonged longer tumourigenic latency compared with those receiving the same dose of free DOX. Our data demonstrate that a CSC-targeting aptamer is able to transform a conventional chemotherapeutic agent into a CSC-killer to overcome drug resistance in solid tumours.

Fattigation-platform nanoparticles using apo-transferrin stearic acid as a core for receptor-oriented cancer targeting

A major hurdle in cancer treatment is the precise targeting of drugs to the cancer site. As many cancer cells overexpress the transferrin receptor (TfR), the transferrin (Tf)-TfR interaction is widely exploited to target cancer cells. In this study, novel amphiphilic apo-Tf stearic acid (TfS) conjugates were prepared and characterized by Fourier transform infrared (FTIR) spectroscopy, matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry, and trinitrobenzenesulfonic acid (TNBS) assay. The prepared TfS conjugates were readily self-assembled in water to form nanoparticles (NPs), consisting of TfS as a core of NPs, whose sizes and zeta potentials were determined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and a particle size analyzer. Hydrophilic water-soluble doxorubicin (DOX) was chosen as a model drug. DOX-loaded TfS NPs (NP+DOX), prepared by the adsorption of DOX on the NP surface via the incubation method, were analyzed for their cell targeting and killing efficiencies in TfR-overexpressing A549 and HCT116 cell lines by MTT assay, confocal microscopy, and fluorescence assisted cell sorting (flow cytometry). The data showed that NP+DOX exhibited improved cancer cell targeting and killing properties compared to that reported for free DOX. Further, the cytotoxic efficiency of NP+DOX was comparable to that of PEGylated liposomal product, Doxil^®, while its cellular uptake was higher than that of Doxil^®. Thus, this novel receptor-based TfS NP drug delivery system has great potential to target TfR-overexpressing cancer cells without off-target effects.

Aptamer-mediated survivin RNAi enables 5-fluorouracil to eliminate colorectal cancer stem cells

The development of chemoresistance and inability in elimination of cancer stem cells are among the key limitations of cancer chemotherapy. Novel molecular therapeutic strategies able to overcome such limitations are urgently needed for future effective management of cancer. In this report, we show that EpCAM-aptamer-guided survivin RNAi effectively downregulated survivin both in colorectal cancer cells in vitro and in a mouse xenograft model for colorectal cancer. When combined with the conventional chemotherapeutic agents, the aptamer-guided survivin RNAi was able to enhance the sensitivity towards 5-FU or oxaliplatin in colorectal cancer stem cells, increase apoptosis, inhibit tumour growth and improve the overall survival of mice bearing xenograft colorectal cancer. Our results indicate that survivin is one of the key players responsible for the innate chemoresistance of colorectal cancer stem cells. Thus, aptamer-mediated targeting of survivin in cancer stem cells in combination with chemotherapeutic drugs constitutes a new avenue to improve treatment outcome in oncologic clinics.

Design of Fucoidan Functionalized - Iron Oxide Nanoparticles for Biomedical Applications

This research aims to develop an iron oxide nanoparticle drug delivery system utilizing a recent material discovered from ocean, fucoidan. The material has drawn much interest due to many biomedical functions that have been proven for human health. One interesting point herein is that fucoidan is not only a sulfated polysaccharide, a polymer for stabilization of iron oxide nanoparticles, but plays a role of an anticancer agent also. Various approaches were investigated to optimize the high loading efficiency and explain the mechanism of nanoparticle formations. Fucoidan was functionalized on iron oxide nanoparticles by a direct coating or via amine groups. Also, a hydrophobic part of oleic acid was conjugated to the amine groups for a more favorable loading of poorly water-soluble anticancer drugs. This study proposed a novel system and an efficient method to functionalize fucoidan on iron oxide nanoparticle systems which will lead to a facilitation of a double strength treatment of cancer.

An investigation of effects of modification processes on physical properties and mechanism of drug release for sustaining drug release from modified rice

The aim of this study was to investigate the effect of modification processes on physical properties and explain the mechanism of sustained drug release from modified rice (MR). Various types of Vietnamese rice were introduced in the study as the matrices of sustained release dosage form. Rice was thermally modified in water for a determined temperature at different times with a simple process. Then tablets containing MR and isradipine, the model drug, were prepared to investigate the capability of sustained drug release. Scanning electron microscopy (SEM) was used to determine different morphologies between MR formulations. Flow property of MR was analyzed by Hausner ratio and Carr's indices. The dissolution rate and swelling/erosion behaviors of tablets were evaluated at pH 1.2 and pH6.8 at 37±0.5°C. The matrix tablet containing MR showed a sustained release as compared to the control. The SEM analyses and swelling/erosion studies indicated that the morphology as well as swelling/erosion rate of MR were modulated by modification time, drying method and incubation. It was found that the modification process was crucial because it could highly affect the granule morphologies and hence, leading to the change of flowability and swelling/erosion capacity for sustained release of drug.

Design of sustained release tablet containing fucoidan

The study introduced a new therapeutic agent, fucoidan, which can offer potential medical treatments including anti-inflammatory and anti-coagulant activities, as well as anti-proliferative effects on cancer cells. Fucoidan was included in sustained release formulations expected for an effective plasma drug concentration for approximately 24 h. The matrices based on the two polymers hydroxypropyl methycellulose (HPMC) and polyethylene oxide (PEO) were prepared with various ratios between the polymers and fucoidan. The dissolution profiles of various matrix tablets performed in enzyme-free simulated intestinal fluid (pH 6.8) for 24 h indicated a higher potential of PEO-based matrix tablets in sustaining release of fucoidan. The swelling and erosion of the tablets were also characterized to elucidate the difference among those dissolution profiles.

Superior Performance of Aptamer in Tumor Penetration over Antibody: Implication of Aptamer-Based Theranostics in Solid Tumors

Insufficient penetration of therapeutic agents into tumor tissues results in inadequate drug distribution and lower intracellular concentration of drugs, leading to the increase of drug resistance and resultant failure of cancer treatment. Targeted drug delivery to solid tumors followed by complete drug penetration and durable retention will significantly improve clinical outcomes of cancer therapy. Monoclonal antibodies have been commonly used in clinic for cancer treatment, but their limitation of penetrating into tumor tissues still remains because of their large size. Aptamers, as “chemical antibodies”, are 15-20 times smaller than antibodies. To explore whether aptamers are superior to antibodies in terms of tumor penetration, we carried out the first comprehensive study to compare the performance of an EpCAM aptamer with an EpCAM antibody in theranostic applications. Penetration and retention were studied in in vitro three-dimensional tumorspheres, in vivo live animal imaging and mouse colorectal cancer xenograft model. We found that the EpCAM aptamer can not only effectively penetrate into the tumorsphere cores but can also be retained by tumor sphere cells for at least 24 h, while limited tumor penetration by EpCAM antibody was observed after 4 h incubation. As observed from in vivo live animal imaging, EpCAM aptamers displayed a maximum tumor uptake at around 10 min followed by a rapid clearance after 80 min, while the signal of peak uptake and disappearance of antibody appeared at 3 h and 6 h after intravenous injection, respectively. The signal of PEGylated EpCAM aptamers in xenograft tumors was sustained for 26 h, which was 4.3-fold longer than that of the EpCAM antibody. Consistently, there were 1.67-fold and 6.6-fold higher accumulation of PEGylated aptamer in xenograft tumors than that of antibody, at 3 h and 24 h after intravenous administration, respectively. In addition, the aptamer achieved at least a 4-time better tumor penetration in xenograft tumors than that of the antibody at a 200 μm distances from the blood vessels 3 h after intravenous injection. Taken together, these data indicate that aptmers are superior to antibodies in cancer theranostics due to their better tumor penetration, more homogeneous distribution and longer retention in tumor sites. Thus, aptamers are promising agents for targeted tumor therapeutics and molecular imaging.

Modulation of particle size and molecular interactions by sonoprecipitation method for enhancing dissolution rate of poorly water-soluble drug

Aim of present work was to originally elucidate the roles of ultrasonication method for modulating the size and molecular interactions in controlling release of poorly water-soluble drug. Curcumin was chosen as a model drug. Three types of polymers were investigated as carriers for preparation of polymeric nanoparticles under various ultrasonication conditions and polymer-drug ratios. Changes in drug crystallinity, particle size, and molecular interactions which would be factors enhancing drug dissolution rate were evaluated. Amorphous form of curcumin, size reduction of nanoparticles and interaction between drug and polymer in formulations were attributed to improved drug dissolution rate. Particle size was strongly affected by polymer type, polymer-drug ratio and ultrasonication conditions. Interestingly, control of those factors caused differences in molecular interactions of the hydroxyl groups and then, highly affected particle size of the nanoparticles. It was obvious that there was a reciprocal influence between the drug-polymer interactions and particle size of the nanoparticles. This relation could be modulated by polymers and ultrasonication processes for enhancing drug dissolution rate.

Polymer conjugate-based nanomaterials for drug delivery

The structure of polymeric amphiphiles with both hydrophilic and hydrophobic groups forming self-assembled nanoparticles have attracted increasing attention in studies of delivery systems of therapeutic agents. An amphiphilic carrier for self-assembly in an aqueous solution is preferable because of its structure with a hydrophobic core and hydrophilic outer shell, which can be applied to many biotechnological and pharmaceutical fields with numerous types of drugs. An amphiphilic carrier for self-assembly also represents the most appealing delivery system owing to its exceptional advantages in selectively delivering drugs to tumor cells and thus, reduction of side effects. This paper reviews two types of self-assembled nanoparticles/micelles of conjugated polymeric amphiphiles: (1) self-assembled micelles/nanoparticles of amphiphilic conjugates followed by drug loading and (2) self-assembled micelles/nanoparticles of polymer-drug conjugates where a conjugation reaction occurs between the polymer and drug. The development of the research has been addressed in this review with up-to-date references. In conclusion, the challenges and remaining difficulties for the future development are discussed.

Enhanced solubility and modified release of poorly water-soluble drugs via self-assembled gelatin-oleic acid nanoparticles

Recently, we synthesized novel amphiphilic gelatin-oleic acid (GO) conjugate to prepare self-assembled nanoparticles for drug delivery. The aim of this study was to investigate pharmaceutical potentialities of self-assembled GO nanoparticles for solubility enhancement and modified release of poorly water-soluble drugs. Three poorly water-soluble model drugs with different pH-dependent solubility (valsartan and aceclofenac, insoluble at pH 1.2; telmisartan, insoluble at pH 6.8) were chosen to investigate the potential contributions of self-assembled GO nanoparticles to solubility enhancement and controlled release. The particle size of the drug-loaded nanoparticles was 200-250 nm. Zeta potential was calculated, and instrumental analysis such as powder X-ray diffraction (PXRD) and Fourier transform infrared (FT-IR) spectroscopy were used to investigate the physicochemical properties of the drug-loaded nanoparticles. Compared to the drug alone, the drug-loaded nanoparticles showed enhanced solubility. Furthermore, the release profiles of the model drugs were modified in a controlled manner. The current self-assembled GO nanoparticles can provide a versatile potential in drug delivery and tumor targeting.

Effects of solvents and crystallization conditions on the polymorphic behaviors and dissolution rates of valsartan

For the quality evaluation of raw materials, the influence of various types of solvents on the polymorphic crystallization behaviors and dissolution rates of two sources of valsartan (VAL) from China and India was investigated. Samples were prepared by recrystallization from water or organic solvents, such as acetonitrile, acetone and ethanol, using methods with and without heating. Recrystallization behaviors were characterized by differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD). Scanning electron microscopy (SEM) was also used to observe the morphology of samples. The dissolution rate of recrystallized samples in water was evaluated and compared to the original VAL sample. There were significant differences in morphology, crystal structure and dissolution rate among the samples recrystallized using organic solvents. VAL was transformed into another polymorphic form by the solvents and recrystallization conditions. These physical properties of VAL also differed between the two sources of VAL. Thus, the physicochemical differences of raw materials should be carefully considered in early dosage formulation approaches.

Investigation of physicochemical factors affecting the stability of a pH-modulated solid dispersion and a tablet during storage

The stability of solid dispersions (SD) during storage is of concern. We prepared the pH-modulated SD (pSD) and compressed tablets consisting of polyethylene glycol (PEG) 6000 as a carrier, drug and MgO (alkalizer). Telmisartan (TEL), an ionizable poorly water-soluble drug, was chosen as a model drug. The changes in physicochemical factors such as the dissolution rate, drug crystallinity, microenvironmental pH (pH(M)) and intermolecular interactions of the pSD and the tablets were investigated over 3 months under different temperature and relative humidity (RH) conditions: refrigerator (5-8 °C), 25 °C/32% RH, 25 °C/55% RH, 25 °C/75% RH, 40°C/32% RH, 40 °C/55% RH, and 40 °C/75% RH. Differential scanning calorimetry (DSC) analysis of all samples revealed no distinct changes in the drug melting point. In contrast, powder X-ray diffraction (PXRD) diffractograms revealed that samples stored at 40 °C/75% RH for 1 month, 25 °C/75% RH for 3 months and 40 °C at all humidity conditions for 3 months showed gradual recrystallization of the drug. Fourier transform infrared (FTIR) spectra indicated a reduced intensity of intermolecular interactions between TEL and MgO in the pSD and tablet. The pH(M) also gradually decreased. These altered physicochemical factors under the stressed conditions resulted in decreased dissolution profiles in intestinal fluid (pH 6.8). In contrast, the dissolution rate in gastric fluid (pH 1.2) was almost unchanged because of the high intrinsic solubility of TEL at this pH.

Design and mechanism of on-off pulsed drug release using nonenteric polymeric systems via pH modulation

The aim was to design a pH-sensitive pulsatile drug delivery system that allows for an on-off pulsed release of a drug using polyacrylic acid (PAA) blended with ethyl cellulose (EC) in different ratios. PAA, a polyelectrolyte polymer, exhibits a highly coiled conformation at low pH but a highly extended structure at high pH. Fumaric acid, which is an internal acidifying agent, was incorporated into the hydroxypropyl methylcellulose-based core tablets to create an acidic microenvironmental pH (pH(M)). The concentration of fumaric acid inside the core tablet and the ratio of PAA/EC in the coating layer were very crucial in modulating drug release behaviors. When the fumaric acid was retained in the core tablet, it gave a more acidic pH(M), so that the PAA was kept in a highly coiled state in the coated film, which hindered drug release ("off" release pattern). Interestingly, the release profiles of the drug and fumaric acid from coated tablets showed the on-off pulsed pattern upon dissolution. Imaging analyses using scanning electron microscopy, near-infrared imaging, confocal laser scanning microscopy, and Fourier transform infrared spectroscopy confirmed this on-off release behavior of the drug and fumaric acid from coated tablets.