Preparation Of Microparticles Research Articles

Novelkaraya gum micro-particles loaded Ganoderma lucidum polysaccharide regulate sex hormones, oxidative stress and inflammatory cytokine levels in cadmium induced testicular toxicity in experimental animals

Presented research aimed to develop a spray drying process without the use of organic solvents for the preparation of novel Karaya gum polymer microparticles (MPs) of Ganoderma lucidum polysaccharide (GLP). The prepared microparticles were characterized and evaluated. Prepared novel karaya gum micro-particles loaded Ganoderma lucidum polysaccharide (GLP MPs) were observed an effect on cadmium (CAD) induced testicular toxicity. A total of 40 rats (male) was divided into 4 groups viz. 1. Control group, 2. GLP MPs (250 mg/kg, 60 days of b.w per day), 3. CAD (60 days of 30 mg/l/day), 4. GLP MPs + CAD. CAD was responsible for altering the sex hormones, oxidative stress and inflammatory cytokines. Furthermore, elevated levels of indicator of oxidative stress, malondialdehyde, and a reduced action of SOD, GSH, and CAT (antioxidant enzymes), were observed in the tissues of the testicles of CAD- treated group. Such harmful occurrences were followed by an up-regulation in proinflammatory cytokines (TNF-α, IL-1β) levels, protein expression of Nrf2, and HO-1 expression was decreased. GLP MPs pre-treatment significantly abrogated these toxic effects which were confirmed histologically. This study concluded that pre-treatment with GLP MPs exerts a protective effect against CAD-induced male reproductive testicular toxicity.

Tailoring of advanced poly(lactic acid)‐based materials: A review

AbstractPoly(lactic acid) (PLA) stands out as the most promising biodegradable alternative to conventional petrochemical‐based polymers for manufacturing of high‐performance materials applied in medicine, pharmacy, food, textile, and electronic industry. This review was aimed to present the conventional and up‐to‐date technologies for PLA processing including melt blending and molding, hot melt extrusion, 3D printing, foaming, impregnation, thermally induced phase separation, nano‐ and microparticles preparation, wet and dry spinning processes. In addition, the effect of the processing parameters and polymer characteristics on the properties of the final material was elaborated. Diverse possibilities to tailor properties of PLA‐based materials by variation in polymer characteristics and concentration, solvent selection, drying method, processing pressure and temperature, incorporation of bioactive components, and so on were highlighted. The examples of the relations between processing methods, parameters, and end‐product properties are given for a better understanding of all aspects that need to be perceived for fabrication of PLA‐based materials with required performances.

INVESTIGATING BETANIN STABILITY, RELEASE PROFILE AND ANTIOXIDANT ACTIVITY OF ETHYL CELLULOSE MICROPARTICLE CONTAINING BEETROOT (BETA VULGARIS, LINN) EXTRACT

Objective: The objective of this research is to evaluate the ability of ethyl cellulose (EC) microparticle to protect the beetroot (Beta vulgaris, Linn) active substance. In addition, this research also investigates the effect of polymer concentration during microparticle preparation toward physical characteristics of microparticle, release profile of betanin as well as antioxidant activity of microparticle. Methods: The microparticle was produced using the emulsification method using various concentrations of EC in the organic phase and beetroot extract as the active substances. The physical characterization was carried out including the imaging of microparticle using scanning electron microscope (SEM), zeta potential and encapsulation efficiency (EE). The stability test for an active substance in microparticle was carried out at temperature 40 °C for 28 d. The release profile was evaluated using the dissolution method and the antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH).Results: The result showed that the EC concentration strongly influenced the physical characteristics and EE of beetroot extract in microparticle. The microparticles also had good protection for betanin during storage. The release of active substance from microparticle following Higuchi kinetic. The highest antioxidant activity was found in the microparticle using EC 20%. Conclusion: The EC microparticle is the potential to protect the degradation of antioxidant substance from natural product. However, the physical properties, EE, the ability to prevent degradation of active substance, release rate and antioxidant activity, are strongly influenced by the EC polymer concentration during microparticle preparation.

Preparation of Polymer Microparticles Through Non-aqueous Suspension Polycondensations: Part VI—Analyses of Chemical and Enzymatic Degradation of Poly(Butylene Succinate) (PBS)

Preparation of Polymer Microparticles Through Non-aqueous Suspension Polycondensations: Part VI—Analyses of Chemical and Enzymatic Degradation of Poly(Butylene Succinate) (PBS)

Preparation of Magnetic Hydrogel Microparticles with Cationic Surfaces and Their Cell-Assembling Performance.

Cationic magnetic hydrogel microparticles with high retention on cell surfaces were prepared using a two-step procedure. Using these magnetic hydrogel microparticles, cells were clustered with each other, and cell aggregates were prepared effectively. Cross-linked poly(vinyl alcohol) (PVA) hydrogel microparticles containing iron oxide nanoparticles were prepared. The diameter of the microparticles was in the range of 200-500 nm. Water-soluble cationic polymers containing both trimethyl ammonium (TMA) groups and phenylboronic acid (PBA) groups were synthesized for the surface modification of the microparticles. To regulate the composition, electrically neutral phosphorylcholine groups were introduced into the polymer. Covalent bonds were formed between the hydroxy groups of PVA microparticles and PBA groups in the polymer. The surface zeta potential of the microparticles reflected the composition of the TMA groups. The particles responded to an external magnetic field and clustered rapidly. Microparticles were adsorbed on the floating cell surface and induced cell aggregation quickly when a magnetic field was applied. Under the most effective conditions, the diameter of the cell aggregates increased to approximately 1 mm after 30 min. Denser cell aggregates were formed by the synergistic effects of the magnetic field and the properties of the microparticles. The formed cell aggregates continued to grow for more than 4 days under an applied magnetic field, indicating that the ability of the cells in the aggregate to proliferate was well maintained.

Preparation of Daidzein microparticles through liquid antisolvent precipitation under ultrasonication

In this study, daidzein microparticles (DMP) were prepared using an improved ultrasound-assisted antisolvent precipitation method. Preliminary experiments were conducted using six single-factor experiments, and principal component analysis (PCA) was adopted to obtain the three staple elements of the ultrasonic power, solution concentration, and nozzle diameter. The response surface Box-Behnken (BBD) design was used to optimize the level of the above factors. The optimal preparation conditions of the DMP were obtained as follows: the flow rate was 4 mL/min, the concentration of the daidzein solution was 16 mg/mL, the ratio of antisolvent to solvent (liquid-to-liquid ratio) was 9, the nozzle diameter was 300 μm, the ultrasonic power was 180 W (665 W/L), and the system speed was 760 r/min. The minimum average particle size of DMP was 181 ± 2 nm. The properties of daidzein particles before and after preparation were analyzed via scanning electron microscopy, X-ray diffraction analysis, Differential scanning calorimetry and Fourier transform infrared spectroscopy, no obvious change in its chemical structure was observed, but crystallinity was reduced. Compared with daidzein powder, DMP has a higher solubility and stronger antioxidant capacity. The above results indicate that the improved method of ultrasonication combined with antisolvent can reduce the size of daidzein particles and has a great potential in practical production.

Microfluidic Preparation of Janus Microparticles With Temperature and pH Triggered Degradation Properties.

Based on the phase separation phenomenon in micro-droplets, polymer-lipid Janus particles were prepared on a microfluidic flow focusing chip. Phase separation of droplets was caused by solvent volatilization and Janus morphology was formed under the action of interfacial tension. Because phase change from solid to liquid of the lipid hemisphere could be triggered by physiological temperature, the lipid hemisphere could be used for rapid release of drugs. While the polymer we selected was pH sensitive that the polymer hemisphere could degrade under acidic conditions, making it possible to release drugs in a specific pH environment, such as tumor tissues. Janus particles with different structures were obtained by changing the experimental conditions. To widen the application range of the particles, fatty alcohol and fatty acid-based phase change materials were also employed to prepare the particles, such as 1-tetradecanol, 1-hexadecanol and lauric acid. The melting points of these substances are higher than the physiological temperature, which can be applied in fever triggered drug release or in thermotherapy. The introduction of poly (lactic-co-glycolic acid) enabled the formation of multicompartment particles with three distinct materials. With different degradation properties of each compartment, the particles generated in this work may find applications in programmed and sequential drug release triggered by multiple stimuli.

Size‐Controlled Formation of Polymer Janus Discs

AbstractA straightforward method is presented for the preparation of nano‐ to micrometer‐sized Janus discs with controlled shape, size, and aspect ratio. The method relies on cross‐linkable ABC triblock terpolymers and involves first the preparation of prolate ellipsoidal microparticles by combining Shirasu porous glass (SPG) membrane emulsification with evaporation‐induced confinement assembly (EICA). By varying the pore diameter of the SPG membrane, we produce Janus discs with controlled size distributions centered around hundreds of nanometers to several microns. We further transferred the discs to water by mild sulfonation of PS to polystyrene sulfonic acid (PSS) and verified the Janus character by subsequent labelling with cationic nanoparticles. Finally, we show that the sulfonated Janus discs are amphiphilic and can be used as efficient colloidal stabilizers for oil‐in‐water (O/W) emulsions.

Size-Controlled Formation of Polymer Janus Discs.

A straightforward method is presented for the preparation of nano‐ to micrometer‐sized Janus discs with controlled shape, size, and aspect ratio. The method relies on cross‐linkable ABC triblock terpolymers and involves first the preparation of prolate ellipsoidal microparticles by combining Shirasu porous glass (SPG) membrane emulsification with evaporation‐induced confinement assembly (EICA). By varying the pore diameter of the SPG membrane, we produce Janus discs with controlled size distributions centered around hundreds of nanometers to several microns. We further transferred the discs to water by mild sulfonation of PS to polystyrene sulfonic acid (PSS) and verified the Janus character by subsequent labelling with cationic nanoparticles. Finally, we show that the sulfonated Janus discs are amphiphilic and can be used as efficient colloidal stabilizers for oil‐in‐water (O/W) emulsions.

Facile preparation of edelweiss-like ZnO microparticles with strong UV-violet emission

Here, a single-step wet-chemical synthetic approach to fabricate novel hierarchically-structured edelweiss-like ZnO microparticles is reported. The construction of microparticles with an average size of 2.7 μm was accomplished within 3 min via hydrolysis of tetraamminezinc (II) complex at dynamic underwater Leidenfrost conditions. The possible formation mechanism of the microparticles was discussed and their microstructural and optical properties were examined. Photoluminescence studies at room temperature showed that the as-prepared ZnO possesses an intense UV-violet emission (370–422 nm range), while the low-temperature annealing at 200 °C leads to the predominant UV-violet-blue co-emission. In addition, the relationship between the photoluminescence properties of microparticles and the type of intrinsic defects in ZnO was analyzed.

Biodegradable Microparticles for Bone Tissue Regeneration Based on Polylactide and Hydroxyapatite Nanoparticles

The process of forming hybrid microparticles from a biodegradable polyester, that is, polylactide, and hydroxyapatite nanoparticles, which can be promising as cellular microcarriers or starting materials for obtaining three-dimensional scaffolds for bone tissue regeneration, has been investigated. A method has been developed for fabricating hybrid microparticles by evaporation of solvents from oil/water emulsions without the use of additional emulsifiers in a dispersion phase. It is shown that hydroxyapatite nanoparticles can effectively stabilize the interface during the preparation of microparticles. The effect of the concentration of hydroxyapatite nanoparticles and their preliminary dispersion using ultrasonic treatment on the yield of microparticles, their size distribution and morphology was evaluated.

Preparation of Nickel Oxide Microparticles by Pulsed Laser Ablation and Application to Gas Sensors

Nickel oxide (NiO) microparticles were synthesized by pulsed laser ablation in double deionized water and intensively studied using Nd:YAG laser. The obtained sample was examined by X-ray diffraction, XRD measurement which tests the existence of polycrystalline. The structural parameters introduced and surface morphology was studied using field emission scanning electron microscopy devices. The optical properties of microparticles in a liquid were investigated through UV-VIS spectroscopy. The CO/CO2 sensing properties of the NiO microstructure sensors were systematically investigated, and the effects of different laser fluencies on the CO/CO2 sensing characteristics were analyzed. XRD measurements reflected the existence of polycrystalline, the optical result shows that The absorption spectra peak centered around 360 nm and a tail extending to the red region (600 nm), the scanning electron microscopy images showed that the morphologies of NiO thin films have microspheres in various. The sample affected by laser fluence 1.9 J/cm2 which exhibits the best sensitivity for CO2 gas.

Block Copolymer Nanoparticles are Effective Dispersants for Micrometer-Sized Organic Crystalline Particles.

Well-defined sterically stabilized diblock copolymer nanoparticles of 29 nm diameter are prepared by RAFT aqueous emulsion polymerization of methyl methacrylate using a dithiobenzoate-capped poly(glycerol monomethacrylate) precursor. These nanoparticles are evaluated as a dispersant for the preparation of organic crystalline microparticles via ball milling. This is exemplified for azoxystrobin, which is a broad-spectrum fungicide that is widely used to protect various food crops. Laser diffraction and optical microscopy studies indicate the formation of azoxystrobin microparticles of approximately 2 μm diameter after ball milling for 10 min at 400 rpm. Nanoparticle adsorption at the surface of these azoxystrobin microparticles is confirmed by electron microscopy studies. The extent of nanoparticle adsorption on the azoxystrobin microparticles can be quantified using a supernatant assay based on solution densitometry. This technique indicates an adsorbed amount of approximately 5.5 mg m–2, which is sufficient to significantly reduce the negative zeta potential exhibited by azoxystrobin. Moreover, this adsorbed amount appears to be essentially independent of the nature of the core-forming block, with similar data being obtained for both poly(methyl methacrylate)- and poly(2,2,2-trifluoroethyl methacrylate)-based nanoparticles. Finally, X-ray photoelectron spectroscopy studies confirm attenuation of the underlying N1s signal arising from the azoxystrobin microparticles by the former adsorbed nanoparticles, suggesting a fractional surface coverage of approximately 0.24. This value is consistent with a theoretical surface coverage of 0.25 calculated from the adsorption isotherm data. Overall, this study suggests that sterically stabilized diblock copolymer nanoparticles may offer a useful alternative approach to traditional soluble copolymer dispersants for the preparation of suspension concentrates affecting the context of agrochemical applications.

Preparation of drug microparticles with a narrow size distribution using regular dimples induced by buckling instability

Particle size reduction is effective in increasing the dissolution rate and bioavailability of poorly water-soluble drugs. However, obtaining microparticles without a size distribution or even with a narrow size distribution is difficult with conventional methods, such as milling and antisolvent precipitation. In the novel method used in this study, uniformly sized droplets of a drug solution were first prepared on a polydimethylsiloxane film, and the film was dried thereafter to precipitate drug particles with a narrow size distribution. The uniformly sized droplets were prepared as follows: the surface of the polydimethylsiloxane film was first oxidized through UV-ozone treatment. The stress in the oxidized layer swollen with polar organic solvents caused buckling instability, which induced the formation of regular dimples. A method similar to dip coating was then used to produce uniform droplets in the dimples and prepare drug particles using salicin and nifedipine.

Preparation of microfluidic-based pectin microparticles loaded carbon dots conjugated with BMP-2 embedded in gelatin-elastin-hyaluronic acid hydrogel scaffold for bone tissue engineering application

The controlled delivery of the bone morphogenetic protein-2 (BMP-2) with tracking ability would overcome most of the side effects linked to the burst release and uncontrolled delivery of this growth factor for bone regeneration. Herein, BMP-2-conjugated carbon dots (CDs) was used as noninvasive detection platforms to deliver BMP-2 for therapeutic applications where osteogenesis and bioimaging are both required. With this in mind, the present work aimed to develop a controlled BMP-2-CDs release system using composite scaffolds containing BMP-2-CDs loaded pectin microparticles, which had been optimized for bone regeneration. By using microfluidic approach, we encapsulated BMP-2-CDs in pectin microparticles with narrow size distribution and then incorporated into composite scaffolds composed of gelatin, elastin, and hyaluronic acid. The BMP-2-CDs was released from the composite scaffolds in a sustained fashion for up to 21 days exhibited a high controlled delivery capacity. When tested in vitro with MG-63 cells, these extraction mediums showed the intercellular uptake of BMP-2-CDs and enhanced biological properties and pro-osteogenic effect. By utilizing the pectin microparticles carrying BMP-2-CDs as promising bioimaging agents for growth factor delivery and by tuning the composition of the scaffolds, this platform has immense potential in the field of bone tissue regeneration.

Improving stability and oral bioavailability of hydroxycamptothecin via nanocrystals in microparticles (NCs/MPs) technology

This study developed a nanocrystals-in-microparticles (NCs/MPs) technology for improving dissolution and oral absorption of poorly soluble drugs. Hydroxycamptothecin (HCPT) was selected as a model drug and prepared to be nanocrystals (HCPT-NCs) by acid-alkali based precipitation. The HCPT-NCs were rod like shape with the length of 250 nm and the width of 50 nm. Then, the chitosan and sodium alginate were selected as microparticles matrix to encapsulate the HCPT-NCs. The HCPT-NCs were entrapped in microparticles with a D50 value of 15 µm. The drug loading capacity of microparticles achieved more than 40% (w/w) by NCs/MPs technology. The powder X-ray diffraction showed the crystal structure of HCPT in microparticles was same as nanocrystals, indicating that the preparation of microparticles could not destroy the nanocrystals. The in vitro release demonstrated that microparticles could protect the NCs in gastric fluid and release NCs in intestinal fluid. Furthermore, the oral bioavailability of HCPT in NCs/MPs was improved by 18-fold compared to bulk HCPT and 2.1-fold compared to HCPT-NCs as tested by a rat model. Therefore, NCs/MPs technology is a promising and high effective approach to improve the oral bioavailability of poorly soluble drugs.

Synthesis, physiochemical properties, colloidal stability evaluation and potential of ionic liquid modified CS-TPP MPs in controlling the release rate of insulin

In the present research, four different ionic liquids (ILs) including 1-Butyl-3-methylimidazolium hydrogen sulfate [BMIM][HSO4], 1-Butyl-3-methylimidazolium acetate [BMIM][OAc], 1-Butyl-3-methylimidazolium chloride [BMIM][Cl], Choline chloride (ChCl) and a surfactant Cetyltrimethylammonium bromide (CTAB) were used in the formulation for preparation of Chitosan-Tripolyphosphate microparticles (CS-TPP MPs) through the ionic gelation method (IGM). The colloidal stability of these MPs was evaluated in HCl medium and the most suitable formulation based on ChCl used for encapsulation of Insulin. All the synthesized MPs are well characterized for size, PDI, zeta potential, structural changes, thermal stability, endo/exothermic behaviour, images, and elemental analysis. The Insulin release experiments were conducted in HCl and PBS mediums, where the MPs containing 0.10–0.40% w/v and 0.10% w/v ChCl evaluated, respectively. In this regard, the formulation containing the 0.10% w/v ChCl protected most of the Insulin successfully (no burst release) in the HCl medium, while a triggered and sustained release occurred in the PBS medium. The kinetic study revealed that the MPs containing the 0.10–0.30% w/v ChCl has a good potential in controlling the release rate of Insulin and the mechanism mainly followed the erosion/relaxation of the polymer matrix with a limited diffusion process.

Preparation of cellulose microparticles having hierarchical internal structures from multiple emulsion templates

Microparticles having porous walls composed of nanofibers of cellulose were prepared from water-in-oil emulsion templates. This was achieved by emulsifying hot solutions of cellulose in a saturated aqueous solution of Ca(SCN)2 in decane in the presence of sorbitan monooleate as an emulsifier. Cooling the emulsion induced micro-phase separation within droplets of the cellulose solution, during which a three-dimensional network of cellulose nanofibers was formed and solidified the droplets. The particles size could be controlled by changing emulsification conditions such as stirring rate, the amount of emulsifier, and the volume ratio between the cellulose solution and decane. We found multiple emulsions (O/W/O and W/O/W/O emulsions) were formed when high amounts (>40 vol%) of the cellulose solution were emulsified. Particles obtained from the multiple emulsions had unique hierarchical internal structures, including a hollow particle with nanofibrous walls and particles-in-particle type structures where multiple porous particles are contained within a particle.

CURCUMIN LOADED POLYMERIC MICROSPHERES FOR VAGINAL DELIVERY: FORMULATION DESIGN, IN VITRO EVALUATION, KINETICS AND STABILITY STUDIES

The main objective of this research is to evaluate a new approach for the preparation of bio adhesive microparticles and to design an innovative vaginal delivery system for curcumin which is able to enhance the drug anticancer activity. Curcumin encapsulated microspheres were prepared by solvent evaporation method. The microspheres were found to be discrete, spherical with free-flowing properties and evaluated for particle size analysis, shape (scanning electron microscopy), drug encapsulation efficiency, FTIR, DSC studies and in vitro release performance. The best selected microsphere formulation (F2, containing drug: polymer ratio 1:2) was incorporated into gels with a bio adhesive polymer. The microencapsulated vaginal gels were evaluated for pH, spreadability, extrudability, viscosity, in vitro drug release, drug release kinetics, bio adhesion test, accelerated stability of selected gel formulation. In vitro drug release rate for selected microencapsulated bio adhesive vaginal gel (FS3 gel, containing 1 % w/w of drug loaded microspheres and 0.6 % w/w of Carbopol 934) was found to sustain curcumin over 12h. The results were then compared statistically and obtained a satisfactory correlation. Thus, in conclusion preparation protocol of microencapsulated vaginal gel study may be adopted for a successful development of newer drug delivery system of other drugs for administration to vagina.

Enzymatic Preparation and Characterization of Spherical Microparticles Composed of Artificial Lignin and TEMPO-Oxidized Cellulose Nanofiber.

A one-pot and one-step enzymatic synthesis of submicron-order spherical microparticles composed of dehydrogenative polymers (DHPs) of coniferyl alcohol as a typical lignin precursor and TEMPO-oxidized cellulose nanofibers (TOCNFs) was investigated. Horseradish peroxidase enzymatically catalyzed the radical coupling of coniferyl alcohol in an aqueous suspension of TOCNFs, resulting in the formation of spherical microparticles with a diameter and sphericity index of approximately 0.8 μm and 0.95, respectively. The ζ-potential of TOCNF-functionalized DHP microspheres was about −40 mV, indicating that the colloidal systems had good stability. Nanofibrous components were clearly observed on the microparticle surface by scanning electron microscopy, while some TOCNFs were confirmed to be inside the microparticles by confocal laser scanning microscopy with Calcofluor white staining. As both cellulose and lignin are natural polymers known to biodegrade, even in the sea, these woody TOCNF−DHP microparticle nanocomposites were expected to be promising alternatives to fossil resource-derived microbeads in cosmetic applications.