Enhancement of dissolution rate and bioavailability of sulfamethoxazole by complexation with β-cyclodextrin

The purpose of this study was to improve the solubility and dissolution rate of sulfamethoxazole (SMZ) with inclusion compound of β-cyclodextrin (β-CD). The interaction between SMZ and β-CD in solution was studied by the phase-solubility method. The phase-solubility studies revealed the formation of inclusion complexes with poor solubility with an inclusion complex of 1:1 molar ratio and a stability constant of 122.3?M(-1). The solid complexes of SMZ with β-CD were prepared by using kneading and coprecipitation methods. The physical mixture of these chemicals was also prepared for comparison. Inclusion complexation was confirmed by the results from the studies of infrared spectoroscopy (IR) and differential scanning calorimetry (DSC). The effect of water-soluble polymers i.e., polyethylene glycol 20000 and non-ionic surfactants i.e., polysorbate 20 on the complexation of SMZ with β-CD was also investigated by the same methods. The rates of release of the active material from the complexes were determined from dissolution studies using USP XXII paddle method. The formulation, that provided delivery of active material near to the target value in six healthy volunteers and in vivo tests, clearly revealed that the bioavailability of active material was found to be enhanced by preparing ternary mixtures.     

Synthesis of β-cyclodextrin hydrogel nanoparticles for improving the solubility of dexibuprofen: characterization and toxicity evaluation

Objective: This study was aimed to enhance aqueous solubility of dexibuprofen through designing β-cyclodextrin (βCD) hydrogel nanoparticles and to evaluate toxicological potential through acute toxicity studies in rats.

Significance: Dexibuprofen is a non-steroidal analgesic and anti-inflammatory drug that is one of safest over the counter medications. However, its clinical effectiveness is hampered due to poor aqueous solubility.

Methods: βCD hydrogel nanoparticles were prepared and characterized by percent yield, drug loading, solubilization efficiency, FTIR, XRD, DSC, FESEM and in-vitro dissolution studies. Acute oral toxicity study was conducted to assess safety of oral administration of prepared βCD hydrogel nanoparticles.

Results: βCD hydrogel nanoparticles dramatically enhanced the drug loading and solubilization efficiency of dexibuprofen in aqueous media. FTIR, TGA and DSC studies confirmed the formation of new and a stable nano-polymeric network and interactions of dexibuprofen with these nanoparticles. Resulting nanoparticles were highly porous with 287?nm in size. XRD analysis revealed pronounced reduction in crystalline nature of dexibuprofen within nanoparticles. Release of dexibuprofen in βCD hydrogel nanoparticles was significantly higher compared with dexibuprofen tablet at pH 1.2 and 6.8. In acute toxicity studies, no significant changes in behavioral, physiological, biochemical or histopathologic parameters of animals were observed.

Conclusions: The efficient preparation, high solubility, excellent physicochemical characteristics, improved dissolution and non-toxic βCD hydrogel nanoparticles may be a promising approach for oral delivery of lipophilic drugs.     

Single palladium atoms stabilized by β-FeOOH nanorod with superior performance for selective hydrogenation of cinnamaldehyde

Atomically dispersed single atom catalysts represent an ideal means of converting less valuable organics into value-added chemicals of interest with high effici...     

Boronate affinity-modified magnetic β-cyclodextrin polymer for selective separation and adsorption of shikimic acid

Polymer of cyclodextrin (CD) is still of great sustainable interest in the scientific research attributing to its excellent physicochemical properties. Owing to its water solubility and superior binding capacity, CD is usually modified through various strategies to exploit its application area. Herein, for the first time, magnetic β-cyclodextrin (β-CD) polymer is endowed with boronate affinity property via mild chemical modifications to specifically separate natural drug raw material shikimic acid (SA). The uniform morphology, magnetic response ability and composition analysis of the porous adsorbent were highly supported by the characterizations. The capture process towards SA depending on the pH value is explored in detail by adsorption kinetics, equilibrium, selectivity and reusability. It is found that specific recognition sites decorated on the surface of magnetic β-CD provides strength support for selective adsorption and separation of shikimic acid. The prepared adsorbent shows high adsorption quantity (Q, mg g^?1) of 31.60 mg g^?1 at 25 °C, high specific recognition and good adsorption capacity (above 83.7%) and stability after five cycles. This study gives a new sight on the utilization of porous β-CD-based material by grafting functional boric acid group for specific capture of natural cis-diol-containing compounds.

     

Enhanced solubility and dissolution rate of amiodarone by complexation with β-cyclodextrin through different methods

The aim of this work was to investigate the inclusion complexation between amiodarone (AMD), a practically water insoluble anti arrhythmic agent, and β-cyclodextrin (βCD) in order to improve the solubility and the dissolution rate of the drug, in an attempt to enhance its bioavailability. The complexation was done through different methods: physical mixture (PM), coevaporated (CV), freeze-drying (FD) and spray-drying (SD). The data analysis indicated that the complexes produced by freeze-drying and spray-drying techniques resulted in amorphous samples (data obtained by DSC and XRPD), and showed a possible chemical interaction between OH-βCD group and AMD tertiary amine (visualized by FT-IR). Also, they presented higher thermal stability (demonstrated by TG) and the improvement of the drug dissolution rate.     

Transitions of calcium carbonate crystals controlled by self-assembly supermolecule of β-cyclodextrin and sodium dodecyl benzene sulfonate

The transitions from vaterite to calcite and from vaterite to aragonite, were found with the anionic surfactant sodium dodecyl benzene sulfonate and β-cyclodextrin as a template, respectively, when the experimental temperature was controlled at 90 °C. The transition from calcite to aragonite was found when the experimental temperature was controlled at 120 °C. The molar ratio of 1:1 and 1:2 supermolecules composed of sodium dodecyl benzene sulfonate ion and β-cyclodextrin molecule may be formed at 90 and 120 °C, respectively. The possible formation mechanisms of different CaCO₃ polymorphs are proposed based on the “structural correspondence”.     

Combination of β-cyclodextrin inclusion complex and self-microemulsifying drug delivery system for photostability and enhanced oral bioavailability of methotrexate: novel technique

In the present study, we prepared an inclusion complex of methotrexate (MTX) with β-cyclodextrin (β-CD) in order to decrease its photosensitivity and enhance its aqueous solubility. Then we incorporated this inclusion complex in a self-microemulsifying drug delivery system (SMEDDS) overall to increase its oral bioavailability. The inclusion complex has been prepared by freeze drying method and characterized by differential scanning calorimetry (DSC), ultraviolet (UV), and infrared (IR) spectroscopy assays. The proper molecular ratio of MTX/β-CD was found to be of 1:7, and the water-solubility of MTX was increased in an average of 10-fold. The photostability studies showed that the MTX became stable on exposure to light. Construction of pseudoternary diagrams were investigated to prepare a MTX/β-CD inclusion complex loaded SMEDDS which was characterized by measuring the particle size and the zeta-potential. The optimum formulation of SMEDDS was a system consisting of ethyl oleate, tween 80, and propylene glycol with a mean droplet size of 39.42?nm. In vitro drug release in different pH media showed that the release profile of MTX from the MTX/β-CD loaded SMEDDS was influenced by the pH of the release medium and presented the characteristics of a sustained release profile. Finally, in-vivo studies showed an enhancement of the bioavailability of MTX from the MTX/β-CD loaded SMEDDS form of 1.57-fold. We concluded that the β-CD inclusion complex loaded SMEDDS improved the chemical and physiological properties of MTX and could be a promising means for the delivery of MTX and other unstable and lipophilic drugs by oral route.     

Beads made of α-cyclodextrin and soybean oil: the drying method influences bead properties and drug release

Freeze-dried beads made of α-cyclodextrin and soybean oil were reported previously as an efficient system for the oral delivery of lipophilic drugs. In the present study, oven-drying was evaluated as another method for drying beads. Oven-drying was optimised and the properties of the resulting beads were assessed. The behavior of oven-dried beads and the release of indomethacin from these beads were evaluated in vitro in simulated gastrointestinal fluids and compared with those of freeze-dried beads. The stability of freeze-dried and oven-dried unloaded beads stored at 25°C for 12 months and at 40°C for 6 months in closed and open vials was also studied by different techniques. An oven-drying time of 6 hours at 25°C was chosen as optimal conditions. Oven-dried beads exhibited a sticky texture making them difficult to handle. They were harder, less fragile and smaller than the freeze-dried ones. The characteristics of oven-dried beads make them more resistant in vitro even in media containing bile salt. The rate of indomethacin release from oven-dried beads was much slower than that from the freeze-dried ones. Whatever the drying method, beads must be stored at room temperature protected from humidity. However, no products of oil degradation were detected with both kinds of beads. This work clearly emphasized that the drying method of the beads had a strong influence on their properties, behavior in simulated gastrointestinal fluids and drug release.     

Theoretical investigation on the inclusion of TCDD with β-cyclodextrin by performing QM calculations and MD simulations

The rapid enrichment and detection of trace polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are currently challenging issues in the field of environmental science. In this paper, by performing quantum chemistry (QM) calculations and molecular dynamics (MD) simulations, we studied the inclusion complexation of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a representative PCDD molecule, with β-cyclodextrin (β-CD), one of the widely used compounds in supramolecular chemistry. The calculated results reveal that the stable inclusion complex can be formed in both the gas phase and solvent, which proposes that β-CD may serve as a potential substrate enriching TCDD. The calculated vibrational spectra indicate that the infrared (IR) and Raman spectroscopy may be suitable for the detection of β-CD-modified TCDD. The present theoretical results may be informative to environmental scientists who are devoting themselves to developing effective methods for detection and treatment of POPs.     

Preparation and characterization of self nano-emulsifying drug delivery system (SNEDDS) for oral delivery of heparin using hydrophobic complexation by cationic polymer of β-cyclodextrin

Objective: The aim of this study was the preparation of a self nano-emulsifying drug delivery system (SNEDDS) for oral delivery of heparin.

Significance: Preparation of hydrophobic complexes between heparin as the hydrophilic macromolecule and cationic polymer of β-cyclodextrin (CPβCD) was considered for preparation of orally administered SNEDDS in which the drug incorporated in internal oil phase of O/W nano-droplets.

Methods: Hydrophobic complexes of heparin-CPβCD were prepared by electrostatic interaction. The lipophilic feature of complexes was characterized by determining their partition co-efficients. SNEDDS prototypes were prepared by mixing liquid paraffin, Tween 80, propylene glycol and ethanol, diluted 1:100 in an aqueous medium. Central composite response surface methodology was applied for statistical optimization. Independent variables were the amount of liquid paraffin and the amount of Tween 80, while responses were size and poly dispersity index (PdI). Optimized SNEDDS were studied morphologically using transmission electron microscopy (TEM). In vitro release of heparin was studied in the simulated gastric and simulated intestinal media.

Results: The data revealed that in molar ratio 1:3 (heparin:CPβCD), the n-octanol recovery was maximized and reached 67.6?±?11.86%. Size, PdI, zeta potential, EE% in gastric medium and EE% in intestinal medium for optimized nano-droplets were reported as 307?±?30.51?nm, 0.236?±?0.02,?+2.1?±?0.66?mV, 90.2?±?0.04 and 96.1?±?0.73%, respectively. Microscopic images revealed spherical nano-droplets. The obtained data revealed no burst release of heparin from nano-droplets.

Conclusions: The obtained results indicate that SNEDDS could be regarded as a good candidate for oral delivery of heparin as the hydrophilic macromolecule.     

ZnO@CdS core–shell thin film: fabrication and enhancement of exciton life time by CdS nanoparticle

In the present study photoluminescence behavior of ZnO and ZnO@CdS core–shell nanorods film has been reported. ZnO nanorods were grown on the glass coated indium tin oxide (ITO) surface by seeding ZnO particle followed with nanorods growth. These nanorods were coated with CdS by chemical bath deposition techniques to have ZnO@CdS thin film and further annealed at 200 °C for their adherence to the ITO surface. The coating was characterized for surface morphology using SEM and optical behavior using UV–visible spectrophotometer. Energy dispersive X-ray (EDX) was used for compositional analysis and time resolve photoluminescence decay for excitons life time measurement. The absorption spectrum reveals that the absorption edge of ZnO@CdS core–shell heterostructure shifted to 480 nm in the visible region whereas ZnO nanorods have absorption maxima at 360 nm. The excitons lifetime of ZnO@CdS was found to be increased with the thickness of the CdS layer on ZnO nanorod. These ZnO@CdS core–shell nanostructures will be of great use in the field of photovoltaic cell and photocatalysis in a UV–visible region.     

Co-delivery of paclitaxel and α-tocopherol succinate by novel chitosan-based polymeric micelles for improving micellar stability and efficacious combination therapy

The aim of this study was to develop chitosan derivative polymeric micelles for co-delivery of paclitaxel (PTX) and α-tocopherol succinate (α-TS) to the cancer cells to improve the therapeutic efficiency and reduce side effects of PTX. In this study, amphiphilic tocopheryl succinate-grafted chitosan oligosaccharide was synthesized and physically loaded by PTX and α-TS with entrapment efficiency of 67.9% and 73.2%, respectively. Physical incorporation of α-TS into the micelles increased the hydrophobic interaction between PTX and the micelles core, which improved micelle stability, reduced the micelle size and also sustained the PTX release from the micelles. The mean particle size and zeta potential of αTS/PTX-loaded micelles were about 133?nm and +25.2?mV, respectively, and PTX release was completed during 6–9?d from the micelles. Furthermore, the cytotoxicity of α-TS/PTX-loaded micelles against human ovarian cancer cell line cancer cell in vitro was higher than that of PTX-loaded micelles and the free drug solution. Half maximal inhibitory concentration values of PTX after 48-h exposure of the cells to the PTX-loaded micelles modified and unmodified with α-TS were 110 and 188?ng/ml, respectively.     

Sinterability of β-SiAlON powder prepared by carbothermal reduction and simultaneous nitridation of ultrafine powder in the Al2O3-SiO2 system

Three types of -SiAlON (Si_{6 – z} Al _z O _z N_{8 – z} ) powder were prepared by the carbothermal reduction and simultaneous nitridation of ultrafine powders in the Al₂O₃-SiO₂ system. The ultrafine starting oxide powders, prepared using the vapour-phase reaction technique, were mixed with carbon powder and heated at 1400 °C for 1 h under flowing nitrogen to form -SiAlON and followed by heating at 570 °C for 1 h in air to remove residual carbon. The resulting powders contained only -SiAlON with z values of 1.63, 2.05, and 2.99. The relative density (bulk density/true density) of -SiAlON compacts pressureless sintered at 1800 °C for 1 h under flowing nitrogen increased with z and reached 89.9% at z = 2.99. When the -SiAlON compact with z = 2.99 was hot pressed at 1800 °C for 1 h under flowing nitrogen, a maximum relative density of 93.6% was achieved. Although this hot pressed compact contained a small amount of 15R-SiAlON in addition to -SiAlON, it possessed a small average grain size (typically 0.5 m diameter) and high Vickers hardness (19.2 GPa).     

Observations and analyses of microstructural defects for chemical vapour deposited β-SiC by transmission electron microscopy

A transparent silicon carbide was grown by a cold-wall chemical vapour deposition (CVD) system using CH₃SiCl₃ and hydrogen gas mixtures on to a graphite substrate. Transmission electron microscopy was used to observe microstructural defects of CVD -SiC, usingg.b = 0,±1/3 and theg.R _F = integer criterion, quantitative information on defects can be obtained. Theb was identified as 1/6 [11¯2] for Shockley partial dislocations andR _F as 1/3[¯111], 1/3 [1¯11], 1/3 [11¯1] for stacking faults. Twin planes were identified as (11¯1), (¯11¯1) in this study. Stacking faults and twins always existed on {111}. Subgrains were surrounded by dislocation networks and full of microtwins. Other defects, such as dislocation loops and dislocation dipoles, were also observed.     

Patterned growth of β-Ga2O3 thin films for solar-blind deep-ultraviolet photodetectors array and optical imaging application

Solar-blind deep-ultraviolet (DUV) photodetectors based on Ga2O3 have attracted great attention due to their potential applications for many military and civil purposes.However,the development of device integration for optoelectronic system applications remains a huge challenge.Herein,we report a facile method for patterned-growth of high-quality β-Ga2O3 thin films,which are assembled into a photodetectors array comprising 8 × 8 device units.A representative detector exhibits outstanding photoresponse performance,in terms of an ultra-low dark current of～0.62 pA,a large Ilight/Idark ratio exceeding 104,a high responsivity of ～0.72 A W-1 and a decent specific detectivity of ～4.18 × 1011 Jones,upon 265 nm DUV illumination.What is more,the DUV/visible (250/400 nm) rejection ratio is as high as 103 with a sharp response cut-offwavelength at ～280 nm.Further optoelectronic analysis reveals that the photodetectors array has good uniformity and repeatability,endowing it the capability to serve as a reliable DUV light image sensor with a decent spatial resolution.These results suggest that the proposed technique offers an effective avenue for patterned growth of β-Ga2O3 thin films for multifunctional DUV optoelectronic applications.     

Dispersion of CaCO3 nanoparticles by sonication and surfactant treatment for application in fly ash–cement systems

This research aims to offset the negative effects of fly ash on the early-age properties of cementitious materials with the use of calcium carbonate (CaCO₃) nanoparticles. The main focus is to enhance the effect of the nanoparticles by improving dispersion through ultrasonication and use of surfactants. CaCO₃ aqueous suspensions with various surfactant types and concentrations are prepared and subjected to different sonication protocols (varying duration and amplitude). Dispersion and stability are quantitatively measured by comparing their absorbance spectra through spectrophotometry and qualitatively evaluated through SEM imaging. The effectiveness of sonicated CaCO₃ nanoparticle additions in accelerating setting and improving early-age compressive strength gain of fly ash–cement pastes is investigated. The sonication protocol is optimized and the most effective dispersion is achieved with polycarboxylate-based superplasticizer. Good agreement is found between the dispersion measurements and mechanical performance.     

Nanosilica-decorated sponges for efficient oil/water separation: role of nanoparticle’s type and concentration

Oil absorption by porous materials is currently regarded as a very efficient method for water purification and oil spill cleanup. Simultaneous induction of superhydrophobic and superoleophilic properties into porous materials was conducted in this study via surface decoration of sponges by nanosilica. The main aim was to investigate the effects of nanosilica concentration on the final wetting behavior of the sponges. To this end, the sponges were treated with both modified and unmodified nanosilica particles through a simple dipping process. It was found that only a moderate concentration of nanoparticles (2 vol%) causes the sponges surface to be uniformly decorated with silica. Based on X-ray photoelectron spectroscopy results, it was postulated that surface energy of the sponges was a more influential factor in the final wetting behavior as compared with the surface roughness. The values of oil absorption capacity were varied in the range of 51–72 g/g (gram of oil per gram of sponge) for the superhydrophobic sample using four different oils and organic liquids. It was concluded that the prepared sponges definitely possess promising potential in the separation of oil/water mixtures provided that an optimum concentration of nanosilica with proper surface modification is used.     

Carboxymethyl-β-cyclodextrin conjugated magnetic nanoparticles as nano-adsorbents for removal of copper ions: synthesis and adsorption studies

A novel nano-adsorbent, carboxymethyl-β-cyclodextrin modified Fe(3)O(4) nanoparticles (CMCD-MNPs) is fabricated for removal of copper ions from aqueous solution by grafting CM-β-CD onto the magnetite surface via carbodiimide method. The characteristics results of FTIR, TEM, TGA and XPS show that CM-β-CD is grafted onto Fe(3)O(4) nanoparticles. The grafted CM-β-CD on the Fe(3)O(4) nanoparticles contributes to an enhancement of the adsorption capacity because of the strong abilities of the multiple hydroxyl and carboxyl groups in CM-β-CD to adsorb metal ions. The adsorption of Cu(2+) onto CMCD-MNPs is found to be dependent on pH and temperature. Adsorption equilibrium is achieved in 30 min and the adsorption kinetics of Cu(2+) is found to follow a pseudo-second-order kinetic model. Equilibrium data for Cu(2+) adsorption are fitted well by Langmuir isotherm model. The maximum adsorption capacity for Cu(2+) ions is estimated to be 47.2mg/g at 25 °C. Furthermore, thermodynamic parameters reveal the feasibility, spontaneity and exothermic nature of the adsorption process. FTIR and XPS reveal that Cu(2+) adsorption onto CMCD-MNPs mainly involves the oxygen atoms in CM-β-CD to form surface-complexes. In addition, the copper ions can be desorbed from CMCD-MNPs by citric acid solution with 96.2% desorption efficiency and the CMCD-MNPs exhibit good recyclability.     

Solid lipid nanoparticles with and without hydroxypropyl-β-cyclodextrin: a comparative study of nanoparticles designed for colonic drug delivery

New solid lipid nanoparticles (SLN), composed of Compritol ATO888 (C) and hydroxypropyl-β-cyclodextrin (HP), were developed in order to study a new colon-specific formulation for diclofenac sodium (D) delivery. The prepared batches differ from each other by the molecular ratio between HP and D and by the composition of the matrix. Nanoparticles composed of an exclusively lipid matrix and nanoparticles with an oligomeric and lipid matrix were compared in order to establish the effect of both components on the drug delivery tests performed. The SLN preparation method was based on the oil/water hot homogenization process. Emulsions produced were cooled at room temperature and lyophilized in order to obtain dried nanoparticles; possible damage to nanoparticle shape and size was avoided by the addition of cryoprotectants to the aqueous dispersion of nanoparticles before exsiccation. An in vitro toxicity study was performed using CaCo(2) cells to establish the safety of the prepared SLN. Data obtained showed that production method studied guarantees emulsions composed of nanosized drops which can be dried by lyophilization into SLN with a size range of 300-600 nm. In vitro and ex vivo tests demonstrated that dried SLN can be considered as colon delivery systems; however, the matrix composition as well as the presence of cryoprotectant on their surface influences the release and permeation rate of D. The in vitro toxicity studies indicated that the SLN are well tolerated.