pH‐Sensitive pectin polymeric rafts for controlled‐release delivery of pantoprazole sodium sesquihydrate

The aim of the present work was to develop pectin raft‐forming tablets for controlled‐release delivery of pantoprazole sodium sesquihydrate (PSS). A Box–Behnken design was used to optimize 15 formulations with three independent and three dependent variables. The physical tests of all compressed formulations were within pharmacopoeial limits. The rafts were characterized by their strength, thickness, resilience, reflux resistance, acid‐neutralizing capacity, floating lag time, and total floating time. The raft strength, thickness, resilience, and reflux resistance through a 10‐mm orifice of optimized formulation PR9 were 7.43 ± 0.019 g, 5.8 ± 0.245 cm, greater than 480 min, and 2490 ± 0.004 g, respectively. The buffering and neutralizing capacity was 11.2 ± 1.01 meq and 6.5 ± 0.56 meq, respectively. Dissolution studies were performed by using simulated gastric fluid at pH 1.2, and the cumulative percentage release of PR9 was found to be 97%. First‐order release kinetics were followed, and non‐Fickian diffusion was observed as the value of n was greater than 0.45 in the Korsmeyer–Peppas model. The Fourier transform infrared spectra of the PSS, polymers, and optimized raft formulation PR9 showed peaks at 3223.09 cm^?1, 1688.17 cm^?1, 1586.67 cm^?1, 1302.64 cm^?1, and 1027.74 cm^?1 that are due to ? OH stretching, ester carbonyl group (C?O) stretching, the existence of water and carboxylic groups in the raft, C? N stretching, and ? OH bending vibrations and showed no interaction between them. The developed raft was suitable for sustained‐release delivery of PSS. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44442.     

Optimization of spray-dried diclofenac sodium-loaded microspheres by screening design

The aim of the present study was to investigate the effect of formulation and operating parameters of the laboratory spray dryer on polymeric microspheres intended to be used for sustaining drug delivery of diclofenac sodium (DS). Four operating and four formulation parameters were investigated by Plackett–Burman design to enhance the encapsulation efficiency (EE). The independent variables were air inlet temperature, aspirator, feed flow rate, spray nozzle diameter, amount of drug, amount of polymers, and volume of organic solvent. The resultant microspheres were characterized for their EE. The microspheres having high EE were further characterized for particle size, morphology, and in vitro drug release. Interaction between the drug and the polymer were investigated by Fourier transform infrared (FTIR) spectroscopy and X-ray powder diffractometry (XRPD). The Pareto chart showed that amount of Eudragit® RS100, amount of ethylcellulose, and aspirator were identified as significant factors. The microspheres showed high EE (47.55?±?0.006% to 67.99?±?0.007%). The microspheres were found to be discrete, spherical with smooth surface. The FTIR analysis confirmed the compatibility of DS with the polymers without interaction. The XRPD revealed the dispersion of drug within microspheres formulation. The in vitro drug release from these DS-loaded microspheres showed sustained release of DS over a period of 12?h and followed the Korsmeyer–Peppas model [R²?=?0.9920 (Run 1) and 0.9957 (Run 13)] with a value of the slope (n)?≤?0.43. This n value, however, appears to indicate that Fickian release is the dominant mechanism of drug release with these formulations.     

PEG and PEG-peptide based doxorubicin delivery systems containing hydrazone bond

mPEG and mPEG-peptide based drug delivery systems were prepared by conjugating doxorubicin (DOX) to these carrier molecules via hydrazone bond. The peptide, AT1, with a sequence of CG₃H₆G₃E served as mPEG and doxorubicin attachment site. Histidines were incorporated to the sequence to improve pH responsiveness of the carrier molecule. Hydrodynamic diameters (mean sizes) of mPEG-based drug delivery system (mPEG-HYD-DOX) were measured as 9?±?0.5 and 7?±?0.5 nm at pH 7.4 and pH 5.0, respectively. Mean size of the aggregates of the peptide containing drug delivery system, mPEG-AT1-DOX, was determined as 12?±?2 nm at neutral pH. At pH 5.0, on the other hand, mPEG-AT1-DOX exhibited a size distribution between 20 and 100 nm centered at about 40 nm. Comparison of % DOX release values of the drug delivery systems obtained at pH 7.4 and pH 5.0 indicated that mPEG-AT1-DOX has enhanced pH sensitivity. DOX equivalent absolute IC₅₀ values were obtained as 0.96?±?0.51, 21.9?±?5.9, and 5.55?±?0.75 μg/mL for free DOX, mPEG-HYD-DOX, and mPEG-AT1-DOX, respectively. Considering more pronounced pH sensitivity and cytotoxicity of mPEG-AT1-DOX, the use of both pH responsive functional groups and acid cleavable chemical bond between the carrier molecule and drug can be a promising approach in the design of drug delivery systems for cancer therapy.     

Synthesis and characterization of injectable chitosan cryogel microsphere scaffolds

Treatment of tissue defects involves invasive processes such as implanting the tissue engineered scaffold to the defected area. Injectable scaffolds are increasingly being developed to achieve tissue regeneration in a less invasive manner. In this study, injectable chitosan cryogels in the form of microspheres were synthesized combining the water in oil emulsification method with the crosslinking of microspheres during cryogelation. The effects of polymer ratio, crosslinker concentration, cryogelation temperature, and stirring speed on the resulting cryogels’ chemistry, pore morphology, microsphere size, swelling ratio, degree of crosslinking, and degradation rate were examined for a possible noninvasive tissue engineering application. Microspheres with optimized properties were developed with an average pore and particle size of 5.50?±?0.63 and 220.11?±?25.58?µm at a chitosan ratio of 1%, glutaraldehyde concentration of 3%, reaction temperature of ?16°C, and stirring rate of 1,000?rpm.     

Controlled release of berberine hydrochloride from alginate microspheres embedded within carboxymethyl chitosan hydrogels

Berberine hydrochloride is a natural medicine with wide clinical application. In this article, berberine hydrochloride was entrapped into alginate microspheres via an emulsification/gelation method. The size distribution of the microspheres was determined by a laser particle sizer. Drug distribution within the microspheres was determined by confocal laser scanning microscopy. Those drug‐loaded microspheres were further entrapped into carboxymethyl chitosan (CMC) hydrogel to form a new drug‐delivery system (DDS). The surface morphology of the DDS was observed using metallographic microscopy and scanning electron microscopy (SEM). The compression strength of the DDSs with alginate microspheres was found significantly higher than that of the pure hydrogel. The drug‐release performances of the DDS in phosphate buffer solution (PBS, pH 7.4), saline solution (pH 6.3), and hydrochloric acid solution (HAS, pH 1.2) were also studied. Decay of the DDS in PBS within 72–80 h results in a faster release; however, the steady release in saline solution could last for all the testing period without cleavage of the DDS. In HAS, because of the shrinkage of the DDS, release is fast in the first period and remains steady later. The DDS exhibits prospective in controlled steady release of drugs. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation of UC ceramic nuclear fuel microspheres by combination of an improved microwave-assisted rapid internal gelation with carbothermic reduction process

Uranium carbide (UC) ceramic microspheres filled into a cladding are a potential nuclear fuel format for nuclear reactors. Uniform sized ceramic UC microspheres with a diameter of 675?±?10?µm were successfully prepared by an improved microwave-assisted rapid internal gelation process combined with carbothermic reduction. First of all, the nanoparticle carbon was dispersed into the HMUR stock solution, and the C-UO₃·2H₂O gelled microspheres were prepared using an improved microwave-assisted internal gelation process without cooling the initial stock solutions. Next, the gelled microspheres were subjected to a carbothermic reduction process to obtain ceramic UC microspheres. TG and XRD investigations indicated that the C-UO₃·2H₂O microspheres were firstly reduced into UO₂ at a temperature of 700?°C, and were further converted into UC at 1500?°C in argon atmosphere. Crack-free ceramic UC microspheres with a smooth and metallic shiny surface were obtained at a sintering temperature of 1500?°C for 5?h with an initial C/U molar ratio of 3.5.     

Chitosan‐coated alginate–polyvinyl alcohol beads for encapsulation of silicone oil containing pyrene: a novel method for biodegradation of polycyclic aromatic hydrocarbons

BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) are potential hazards in the environment owing to their toxic, carcinogenic and recalcitrant nature. Biodegradation of these compounds, although effective compared with other treatment techniques, is problematic owing to its low aqueous solubility and negligible bioavailability. The present study reports a novel method for biodegradation of PAHs using an encapsulated form of the pollutant in chitosan‐coated alginate–polyvinyl alcohol (PVA) beads. RESULTS: A suitable combination of 3% (w/v) PVA, 100 g L^?1 non‐ionic surfactant Brij 30 and 0.3 silicone oil fraction in the formulation was found to be optimal in the preparation of stable emulsion. The emulsion obtained was admixed with alginate (3% w/v) to prepare suitably sized microspheres by an emulsion gelation technique, which were later coated with chitosan to yield a maximum pyrene encapsulation efficiency of 90.7%. Pyrene in silicone oil at concentration as high as 2 g L^?1, when delivered through the chitosan coated alginate–PVA beads, was completely degraded by Mycobacterium frederiksbergense within 10 days without any significant lag phase. CONCLUSION: Using chitosan‐coated alginate–PVA beads sustained release of pyrene and subsequent biodegradation by M. frederiksbergense were achieved. Using the present system, complete degradation of pyrene was attained even at its very high initial concentration and within a short time period. Further advantage offered by this system seems to be negligible toxic effect of pyrene and solvents on the degrading microorganisms since these were in an encapsulated form and were not in direct contact with the organism. Copyright © 2010 Society of Chemical Industry     

Synthesis and characterization of polyvinyl alcohol/dextran/Zataria wound dressing with superior antibacterial and antioxidant properties

The aim of the present research was to synthesize and characterize polyvinyl alcohol/dextran/Zataria essential oil hydrogel wound dressings. For this purpose, dressings were made with different concentrations of polymers (PVA and Dex) and ZMO by solvent casting method. By dissolving PVA and Dextran in de-ionized water, PVA-Dex gel was made. The polymeric solution was mixed with glycerol. The pH of PVA-DEX-Glycerol solution was adjusted to 3 and glutaraldehyde was used as a cross-linker. ZMO, as the antibacterial and antioxidant agent, was added to the samples in different percentages (2,5,10%). It was found that both Dex and ZMO significantly influenced the hydrophilicity, gel fraction, and water uptake capacity of hydrogel films. The results showed that by the addition of Dex to PVA, the contact angle decreased from 48.54° ± 0.95 to 45.90 ± 0.73°, whereas by the addition of ZMO, the contact angle increased to 71.1 ± 2.43. SEM investigations revealed that the fabricated films had a uniform structure and the surface roughness increased with the addition of ZMO. The results indicated an increased elongation of 11.5% with the incorporation of ZMO into the films. The antimicrobial evaluation of the produced films showed that the loading of 10% v/v ZMO could broaden the microbicidal activity of PVA/Dex/ZMO film. The investigations on the interactions between synthesized wound dressings and fibroblast cells showed that the addition of ZMO into hydrogel films improved cell viability. The findings showed that PVA/Dex/ZMO films could have considerable use as wound dressing.     

Oxygen diffusivity in alginate/chitosan microcapsules

BACKGROUND: Oxygen diffusion properties affect the proliferation and metabolism of cells cultured in microcapsules with a polyelectrolyte complex membrane. The effective diffusion coefficient (De) of oxygen in alginate/chitosan (AC) microcapsules under different preparation conditions was calculated, and a mathematic model was developed to investigate the effect of oxygen diffusion on cell loading in the microcapsules. RESULTS: Oxygen De in AC microcapsules was independent of alginate solution concentration, intrinsic viscosity of alginate and different polyelectrolyte complex membranes. De decreased from 2.1 ± 0.3 × 10^?9 to 0.17 ± 0.01 × 10^?9 m² s^?1 as microcapsule diameter decreased from 1800 to 45 0 µm. Microcapsule density was increased from 1.013 ± 0.000 to 1.034 ± 0.003 g mL^?1 as diameter decreased from 1775 to 430 µm. The mathematic model results showed that critical CHO cell loadings were 1.8 × 10⁸ or 1.1 × 10⁸ cells mL^?1 in microcapsules with 450 or 1800 µm diameter, respectively. CONCLUSIONS: No significant difference was found of oxygen De between calcium alginate beads and AC microcapsules. The decrease of De with diameter was attributed to the increasing density and compact degree on the surface. The model results indicated that risk on necrosis rose with the increasing diameter. Microcapsules with smaller diameters may have more advantages on cell culture. © 2012 Society of Chemical Industry     

Fabrication and characterization of porous biphasic β-tricalcium phosphate/carbonate apatite alginate coated scaffolds

In this research, biphasic β-tricalcium phosphate/carbonate apatite (β-TCP/CO₃Ap) scaffolds incorporated with alginate were fabricated. Sodium alginate was extracted from local brown seaweed, Sargassum polycystum via calcium alginate process. Biphasic β-TCP/CO₃Ap scaffolds were fabricated by polymer reticulate method. β-TCP slurry was infiltrated into the polyurethane foam (PU) foam, then sintered up to 1300?°C, soaked for 4?h and immediately quenched in still air to form biphasic β-TCP/α-TCP scaffold. Biphasic β-TCP/α-TCP scaffold was then transformed to biphasic β-TCP/CO₃Ap scaffold by dissolution-precipitation reaction with 1?M of NaHCO₃ at 170?°C for 1, 3 and 5 days. Biphasic β-TCP/CO₃Ap scaffold from 5 days dissolution-precipitation reaction was chosen to incorporate with 1%, 3% and 5% of sodium alginate, respectively, as it has the highest composition of CO₃Ap phase. FTIR and FESEM analysis confirmed the presence of characteristic functional groups of sodium alginate. Mechanical strength of biphasic β-TCP/CO₃Ap scaffold improved by increasing the concentration of sodium alginate. The highest mechanical strength achieved was 26.38 kPa for biphasic β-TCP/CO₃Ap scaffold with 5% sodium alginate coating and it was chosen to further study with the addition of 1%, 3% and 5% microspheres. FESEM analysis confirmed the attachment of microspheres on the surface of alginate/biphasic β-TCP/CO₃Ap scaffold was successful.     

Crystal structure and microwave dielectric properties of NaPb2B2V3O12(B=Mg,Zn) ceramics

Two low temperature sintered NaPb₂B₂V₃O₁₂ (B?=?Mg, Zn) ceramics with garnet structure were synthesized through conventional solid state reaction route and their crystal structure and microwave dielectric properties were investigated for the first time. Rietveld refinements of XRD patterns show both the compounds belong to cubic symmetry with space group Ia-3d. Observed number of Raman bands and group theoretical predictions also confirm cubic symmetry with space group Ia-3d for both NPMVO and NPZVO. At the optimum sintering temperature of 725?°C NPMVO has a relative permittivity of 20.6?±?0.2, unloaded quality factor (Q_uxf) of 22,800?±?1500?GHz (f?=?7.7?GHz) and temperature coefficient of resonant frequency +25.1?±?1?ppm/°C while NPZVO has relative permittivity of 22.4?±?0.2, Q_uxf of 7900?±?1500?GHz (f?=?7.4?GHz) and near zero temperature coefficient of resonant frequency of -6?±?1?ppm/°C at 650?°C. The relative permittivity of the compounds is inversely related to the corresponding Raman shifts.     

Dose response effects of a caffeine-containing energy drink on muscle performance: a repeated measures design

Background

Energy drinks have become the most used caffeine-containing beverages in the sport setting. The aim of this study was to determine the effects of two doses of a caffeine-containing energy drink on muscle performance during upper- and lower-body power-load tests.

Methods

In a randomized order, twelve active participants ingested 1 and 3?mg of caffeine per kg of body weight using a commercially available energy drink (Fure?, ProEnergetics) or the same drink without caffeine (placebo; 0?mg/kg). After sixty minutes, resting metabolic rate, heart rate and blood pressure were determined. Then, half-squat and bench-press power production with loads from 10 to 100% of 1 repetition maximum was determined using a rotator encoder.

Results

In comparison to the placebo, the ingestion of the caffeinated drink increased mean arterial pressure (82?±?7?P?<?59?±?8?<?62?±?8 beats/min, respectively; P?P?P?Conclusions A caffeine dose of at least 3?mg/kg in the form of an energy drink is necessary to significantly improve half-squat and bench-press maximal muscle power.     

TRANSFER RATE AND SEPARATION OF Sr2+ and Cs+ BY SUPPORTED LIQUID MEMBRANES UTILIZING SYNERGIZED CROWN ETHER CARRIERS

ABSTRACT

The rate of the isotopic exchange of Na? and Cs? between hydrous silicon-titanium(IV) oxide in the relevant ionic form and aqueous solution was determined radiochemically. The rate was controlled by the diffusion of the ions in the exchanger particles. The diffusion coefficients at 5 °C are (3.9±0. 1)×10^?11m² s^?1 and (2.4± 0. 1)×10^?11 m² s^?1respectively, for Na? and Cs? in the exchanger equilibrated with solutions at pH 6. The activation energies are 31±5 kJ mol^?1 and 20±5 kJ mol^?1 for Na? and Cs? diffusion, respectively. The diffusion coefficients of the ions decreases with increasing pH of the solutions equilibrated with the exchanger, whereas their activation energy is independent of pH. The results were interpreted in terms of the strength of the electrostatic interaction between the counter ions and the ion-exchange sites.     

The effect of graphene nanoplatelet thickness on the fracture toughness of Si3N4 composites

Si₃N₄ composites with 3 and 5?wt% of graphene nanoplatelet (GNP) additions were prepared by spark plasma sintering. We used both commercially available GNPs and thinner few-layer graphene nanoplatelets (FL-GNPs) prepared by further exfoliation through ball milling with melamine addition. We found that by employing thinner FL-GNPs as filler material a 100% increase in the fracture toughness of Si₃N₄/3?wt% FL-GNP composites (10.5?±?0.2?MPa?m^1/2) can be achieved as compared to the monolithic Si₃N₄ samples (5.1?±?0.3?MPa?m^1/2), and 60% increase compared to conventional Si₃N₄/3?wt% GNP composites (6.6?±?0.4?MPa?m^1/2). For 5?wt% filler content the increase of the fracture toughness was near 50% for both GNP and FL-GNP fillers. The hardness of the composites decreased with increasing GNP content. However, composites reinforced with 5?wt% of FL-GNPs displayed 30% higher Vickers hardness (12.8?±?0.2?GPa) than their counterparts comprising conventional GNP fillers (9.8?±?0.2?GPa). We attribute the enhanced mechanical properties obtained with thinner FL-GNPs to their higher aspect ratio leading to a more homogeneous dispersion, higher interface area, as well as smaller pores in the ceramic matrix.     

Effect of acetic acid on lipid accumulation by glucose‐fed activated sludge cultures

BACKGROUND: The effect of acetic acid, a lignocellulose hydrolysis by‐product, on lipid accumulation by activated sludge cultures grown on glucose was investigated. This was done to assess the possible application of lignocellulose as low‐cost and renewable fermentation substrates for biofuel feedstock production. RESULTS: Biomass yield was reduced by around 54% at a 2 g L^?1 acetic acid dosage but was increased by around 18% at 10 g L^?1 acetic acid dosage relative to the control run. The final gravimetric lipid contents at 2 and 10 g L^?1 acetic acid levels were 12.5 ± 0.7% and 8.8 ± 3.2% w/w, respectively, which were lower than the control (17.8 ± 2.8% w/w). However, biodiesel yields from activated sludge grown with acetic acid (5.6 ± 0.6% w/w for 2 g L^?1 acetic acid and 4.2 ± 3.0% w/w for 10 g L^?1 acetic acid) were higher than in raw activated sludge (1–2% w/w). The fatty acid profiles of the accumulated lipids were similar with conventional plant oil biodiesel feedstocks. CONCLUSIONS: Acetic acid enhanced biomass production by activated sludge at high levels but reduced lipid production. Further studies are needed to enhance acetic acid utilization by activated sludge microorganisms for lipid biosynthesis. Copyright © 2011 Society of Chemical Industry     

Effects of composition and extrusion parameters on the morphological development and rheological properties of PP/PC blends. Co-continuity investigation

In this work, a new dimethacrylate monomer named ??,????-Bis(4-(2??-hydroxy- 3??methacryloyloxy-propoxy)-3,5-dimethylphenyl)-1,4-diisopropyl-benzene (??,????-BHMPDDB) was synthesized to replace 2,2-bis[4-(2??-hydroxy-3??-methacryloyloxy-propoxy)-phenyl]propane (Bis-GMA) as one component of dental composite materials. The structures of ??,????-BHMPDDB and its intermediate product ??,????-Bis(4-oxiranylmethoxy-3,5-dimethylphenyl)-1,4-diisopropylbenzene (??,????-BODDB) were confirmed by FT-IR, ¹H-NMR, and elemental analysis. ??,????-BHMPDDB was mixed with TEGDMA to form a new dental resin, and double bond conversion, polymerization shrinkage, contact angle, water sorption and solubility, flexural strength and modulus before and after water immersion of this new dental resin were studied. Compared with the commonly used Bis-GMA/TEGDMA dental resin, ??,????-BHMPDDB/TEGDMA had higher double bond conversion (60.5?±?0.3?%), lower polymerization shrinkage (5.6?%), and comparable flexural strength before water immersion (94.1?±?3.9?MPa), which made ??,????-BHMPDDB/TEGDMA having potential to replace Bis-GMA/TEGDMA as matrix phase of dental composites materials. However, ??,????-BHMPDDB/TEGDMA also had drawbacks, such as higher water sorption (5.06?±?0.17?%), water solubility (2.37?±?0.1?%), and lower flexural strength after water immersion (71.4?±?14.6?MPa).     

Fabrication and characterisation of nanofibrous polyurethane scaffold incorporated with corn and neem oil using single stage electrospinning technique for bone tissue engineering applications

In bone tissue engineering, the design of scaffolds with ECM is still challenging now-a-days. The objective of the study to develop an electrospun scaffold based on polyurethane (PU) blended with corn oil and neem oil. The electrospun nanocomposites were characterized through scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), contact angle measurement, atomic force microscopy (AFM) and tensile strength. The assays activated prothrombin time (APTT), partial thromboplastin time (PT) and hemolysis assay were performed to determine the blood compatibility parameters of the electrospun PU and their blends of corn oil and neem oil. Further, the cytocompatibility studies were performed using HDF cells to evaluate their proliferation rates in the electrospun PU and their blends. The morphology of the electrospun PU blends showed that the addition of corn oil and corn/neem oil resulted in reduced fiber diameter of about 845?±?117.86?nm and 735?±?126.49 nm compared to control (890?±?116.911?nm). The FTIR confirmed the presence of corn oil and neem oil in PU matrix through hydrogen bond formation. The PU blended with corn oil showed hydrophobic (112°?±?1) while the PU together with corn/neem oil was observed to hydrophilic (64°?±?1.732) as indicated in the measurements of contact angle. The thermal behavior of prepared PU/corn oil and PU/corn/neem oil nanocomposites were enhanced and their surface roughness were decreased compared to control as revealed in the AFM analysis. The mechanical analysis indicated the enhanced tensile strength of the developed nanocomposites (PU/corn oil - 11.88 MPa and PU/corn/neem oil - 12. 96 MPa) than the pristine PU (7.12 MPa). Further, the blood compatibility assessments revealed that the developed nanocomposites possess enhanced anticoagulant nature compared to the polyurethane. Moreover, the developed nanocomposites was non-toxic to red blood cells (RBC) and human fibroblast cells (HDF) cells as shown in the hemolytic assay and cytocompatibility studies. Finally, this study concluded that the newly developed nanocomposites with better physio-chemical characteristics and biological properties enabled them as potential candidate for bone tissue engineering.     

A rapid two-step electroless deposition process to fabricate superhydrophobic coatings on steel substrates

The present study reports a simple, highly effective, and safe two-step electroless deposition process for rapidly fabricating superhydrophobic Ag coatings on steel substrates. The steel plates were first immersed in the 1?mol/L aqueous CuSO₄ solution for 20?s, and then immersed in the 0.03?mol/L aqueous AgNO₃ solution containing 1?wt% fluoroalkylsilane (FAS) for 2?min. The sample surfaces were characterized by energy-dispersive x-ray spectroscopy, Fourier transform infrared spectrophotometry (FTIR), x-ray diffraction, scanning electron microscopy, step profiler, and optical contact angle measurements. The results show that, after the two-step electroless deposition process, the Ag coatings composed of the binary micro/nanometer-scale rough structures containing the FAS molecules with a low surface energy are formed on the steel surfaces. The as-prepared Ag coatings exhibit a good superhydrophobicity with a 163.4?±?1.8° water contact angle and 1.5?±?0.5° rolling angle.     

Investigation on preparation and protein release of biodegradable polymer microspheres as drug‐delivery system

Among the different approaches to achieve protein delivery, the use of polymers, especially biodegraded, holds great promise. This work aimed to study the preparation and protein release of a novel drug‐delivery system based on human serum albumin (HSA) encapsulated into biodegradable polymer microspheres. The microspheres containing HSA were elaborated by the solvent‐extraction method based on the formation of multiple w/o/w emulsion. The encapsulation efficiency (E.E.) of HSA was determined by the CBB method. Alginate/alginate and calcium chloride was added into an internal aqueous phase to investigate the protein loading efficiency, protein stability, and in vitro release profiles. Microspheres were characterized in terms of their morphology, size distribution, loading efficiency, and in vitro protein release. SDS–PAGE results showed that HSA kept its structural integrity during the encapsulation and release procedure. In vitro studies indicated that the microspheres with alginate added in the internal aqueous phase had a smaller extent of burst release. In conclusion, the work presents a new approach for macromolecular drugs (such as protein drugs, vaccines, and peptide drugs) delivery. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 778–784, 2002; DOI 10.1002/app.10327     

Preparation and evaluation of alginate/chitosan microspheres containing pheromones for pest control of Megaplatypus mutatus Chapuis (Platypodinae: Platypodidae)

This work describes the optimization of an alginate/chitosan microsphere preparation for the encapsulation of a sexual pheromone, 6‐methyl‐5‐hepten‐2‐ol (sulcatol), to realize a slow‐release device for the biological control of the Megaplatypus mutatus pest. To evaluate and select the best encapsulation/release conditions three parameters were studied: alginate concentration, pH of gelling solution and Ca²⁺/COO^? ratio. The preparation was optimized using biopolymers with improved mechanical properties and swelling behavior. The obtained microspheres were characterized using Fourier transform infrared spectroscopy, scanning electron and optical microscopies, swelling degree, mechanical properties and in vitro release of encapsulated pheromone. The microspheres performed best when they were synthesized using an alginate concentration of 4% w/v, at pH = 9 and with a Ca²⁺/COO^? ratio of 3.5. The attractiveness of the alginate/chitosan microspheres towards M. mutatus was demonstrated by behavioral bioassay with the completed pheromonal blend of the species (sulcatol, sulcatone and 3‐pentanol). The formulation can be considered as an efficient slow‐release biological control system, with no negative environmental impact. © 2015 Society of Chemical Industry