Hydrophilic Substances Research Articles

Combination of In Situ Feeding Rate Experiments and Chemical Body Burden Analysis to Assess the Influence of Micropollutants in Wastewater on Gammarus pulex.

Wastewater discharge is one of the main sources of micropollutants within the aquatic environment. To reduce the risks for the aquatic environment, the reduction of the chemical load of wastewater treatment plant effluent is critical. Based on this need, additional treatment methods, such as ozonation, are currently being tested in several wastewater treatment plants (WWTPs). In the present study, effects were investigated using in situ feeding experiments with Gammarus pulex and body burden analyses of frequently detected micropollutants which used a Quick Easy Cheap Effective Rugged and Safe (QuEChERS) multi-residue method to quantify internal concentrations in collected gammarids. Information obtained from these experiments complemented data from the chemical analysis of water samples and bioassays, which predominantly cover hydrophilic substances. When comparing up- and downstream feeding rates of Gammarus pulex for seven days, relative to the WWTPs, no significant acute effects were detected, although a slight trend of increased feeding rate downstream of the WWTP Aachen-Soers was observed. The chemical load released by the WWTP or at other points, or by diffuse sources, might be too low to lead to clear acute effects on G. pulex. However, some compounds found in wastewater are able to alter the microbial community on its leaves, leading to an increase in the feeding rate of G. pulex. Chemical analysis of internal concentrations of pollutants in the tissues of collected gammarids suggests a potential risk for chronic effects with the chemicals imidacloprid, thiacloprid, carbendazim, and 1H-benzotriazole when exceeding the critical toxic unit value of −3. This study has demonstrated that a combination of acute testing and measurement of the internal concentration of micropollutants that might lead to chronic effects is an efficient tool for investigating river systems, assuming all relevant factors (e.g., species or season) are taken into account.

Efficacy of dextran and peptide-everolimus bi-directional stent.

Everolimus inhibits stent restenosis and the WKYMV (fluorescein isothiocyanate) peptide promotes endothelial homing. Dextran is a natural polymer that is widely used as a pharmaceutical agent. The purpose of this study was to develop a double-drug-coated stent using a bidirectional coating system and to examine the surface shape with in vitro experiments. Stent length was 16 mm and strut thickness was 70 µm (Chonnam National University Hospital Tiger stent). Optical and scanning electron microscopy showed good coating without cracks or bubbles. Fluorescein isothiocyanate-peptide was dip-coated on the lumen and the abluminal surface was coated with everolimus and dextran. Stents were coated with dextran, everolimus, or everolimus-dextran. The radial force and flexibility were measured to determine the mechanical properties. Contact angle testing was performed in all groups. Dextran and peptide as hydrophilic substances and everolimus as a hydrophobic substance were each coated on cover glasses (cobalt-chromium). A10 and human umbilical vein endothelial cells were used in the experiments. Water and dimethyl sulfoxide served as a control, and three drug groups were tested: peptide-everolimus, everolimus-dextran, and peptide-everolimus-dextran. Immunocytochemistry was performed to assess cell adhesion. Light intensity was plotted according to the average on nuclear staining. Experiments were conducted using 5-bromo-2'-deoxyuridine to investigate A10 and human umbilical vein endothelial cell proliferation. Cell adhesion and proliferation of peptide-everolimus-dextran were inhibited at A10, and human umbilical vein endothelial cell was found to proliferate with cell adhesion. On conclusion, dextran and peptide-everolimus bidirectional stent is effective in re-endothelialization and inhibition of cell proliferation.

Characterization and thermal performance of microencapsulated sodium thiosulfate pentahydrate as phase change material for thermal energy storage

In this work, a novel microencapsulated phase change material based on sodium thiosulfate pentahydrate as core and poly(ethyl-2-cyanoacrylate) as shell was successfully synthesized by interfacial polymerization in a water-in-oil emulsion system. The morphology, microstructure, surface elemental distribution, chemical composition and crystalline structure of the resultant microcapsules were determined by scanning and transmission electron microscopies, energy dispersive spectroscopy, Fourier-transform infrared spectroscopy and X-ray diffraction. Besides, their thermal properties were also investigated systematically by differential scanning calorimetry and thermogravimetry analysis. The results showed that the microcapsules presented almost spherical profiles with a diameter of about 1.0 µm and a well-defined core-shell structure. Meanwhile, the microcapsules possessed phase change temperature of 46.44 °C and latent heat of 107.0 kJ·kg−1 at the core material/monomer mass ratio of 4/2. Due to the protective effect of shell material, the thermal stability of the microcapsules was improved. In addition, the thermal cycling test revealed that the microcapsules had good thermal reliability. Considering the above results, this synthetic technique can be considered as a feasible way to prepare microencapsulated salt hydrates and is expected to extend to the encapsulation of other hydrophilic substances. And the obtained microcapsules have great potential as a solar energy storage material.

NANODISCS: A NEW EPOCH IN THE STUDY OF MEMBRANE PROTEINS AND AS AN EMERGING DRUG DELIVERY SYSTEM

Nano discs recently evolved as a novel tool for studying the membrane associated proteins and serve as an effective drug delivery system. Nano discs constitute disc shaped nano particles and can be defined as a membrane system which is synthetic in nature and aids in the study of membrane proteins. It is mainly made of phospholipid bilayer and the water repelling edge is isolated by amphipathic proteins called membrane scaffolding proteins [MSP]. Micelles present in the nano disc mimics the property of the biological membrane proteins. It is a powerful technology that competently delivers the drug components in to the right cells in the right tissues. Membrane scaffold proteins are primarily expressed, purified and characterized and self-assembled to form Nano discs by the process of dialysis using biobeads. Nano discs are proven to be effective in the study of membrane proteins because they can fluidize and counterbalance and also help in reclusion, refinement, biophysical and biochemical studies of them. It also presents a more genuine environment than liposomes, bicelles, amphipols and detergent micelles. Major technological advantages of nano discs include the higher stability and carrier capacity and also the increased feasibility of incorporating both hydrophilic and hydrophobic substances of drug carrier. Thus nano discs serves as an excellent system in its ability to precisely control its composition and provide a nano scale membrane surface for investigating molecular recognition events. This article reviews the emphasis of nanodiscs in studying membrane proteins as well as its effectivity in transforming into a major drug delivery system. An overview of published literatures between 1996 and 2017 was conducted to write the review.

Anhydrous fluid serum as vehicle for drug delivery formulations: sterility test results for bacterial and fungal growth

Topical delivery of drugs is essential in Dermatology. Due to the difficulty of permeation of the stratum corneum, drug delivery techniques have been highlighted. The use of non-specific formulations for this purpose makes raises the concern of possible adverse events and the microbiological safety of these formulations. Objective: To assess bacterial and fungal growth in anhydrous fluid serum through simple sterility test. Materials and methods: The simple sterility test was performed on an anhydrous serum containing lipophilic and hydrophilic active substances. This test was performed three months after the manufacture of the product. Results: The formulation studied was approved in the simple sterility test conducted three months after the manufacture of the product, even without the use of preservatives in the formulation. Discussion: The assessed formulation was approved in the sterility test possibly due to the fact that the serum vehicle has mineral and anhydrous origin, characteristics that do not favor the proliferation of microorganisms. Conclusions: Although only the vehicle counting specific assets has been tested, the results of this study are promising and demonstrate the need for future studies broadly encompassing this subject

NOM fouling resistance in response to electric field during electro-ultrafiltration: Significance of molecular polarity and weight

Electro-ultrafiltration is an effective method for mitigating membrane fouling. Herein, anti-fouling mechanisms for the electro-ultrafiltration of natural organic matter (NOM) were investigated to illuminate the significance of NOM molecular polarity and weight. Results indicated that the membrane flux of NOM electro-ultrafiltration was greatly enhanced by electric field (EF) application, and that the increase in membrane flux magnitude for electro-ultrafiltration was more pronounced for NOM with higher hydrophilicity and larger molecular weight. The electro-ultrafiltration flux of the hydrophilic substances in NOM was enhanced by up to 20% after applying the voltage. The enhancement of membrane flux was more prominent for the electro-ultrafiltration of humic acid (HA) solution with high ionic strength and coexisting Ca2+. With increasing EF strength in the electro-ultrafiltration of HA, membrane flux increased at first due to the electrokinetic migration of negatively charged HA, and then declined for fields larger than the critical EF, where electro-ultrafiltration reached maximum flux. The HA molecules became polarized under a high EF, which induced aggregation between the molecules and increased affinity between HA and the membrane. This facilitated the formation of a dense cake layer, leading to relatively severe membrane fouling under EF strengths larger than the critical EF.

Separation of Oxidized Pyrrhotite from Fine Fraction Serpentine

The valuable minerals in copper-nickel sulfide ore can easily be oxidized, leading to the reduction of their flotation recovery and a difficulty in separating them from gangue. In order to solve the problem, the reaction mechanism of the octanohydroxamic acid (OHA) on oxidized pyrrhotite was revealed through micro-flotation, adsorption tests, zeta potential measurements, and X-ray photoelectron spectroscopy (XPS) analysis. The results show that this is a feasible way to find a suitable collector that can directly react to oxidation products on the surface of pyrrhotite. OHA can efficiently reclaim oxidized pyrrhotite and achieve the selective separation of a pyrrhotite-serpentine mixture in a weak alkaline environment. The adsorption tests, zeta potential measurements, and XPS analyses show that OHA can interact with an oxidized pyrrhotite surface, and the interaction between OHA and serpentine is very weak. The XPS analyses indicate that the OHA collector can chelate with Fe(OH)3 on the surface of oxidized pyrrhotite and form an “O, O” five-ring chelate. At the same time, the OHA collector may compete with the hydroxyl groups of hydrophilic substances on the mineral surface to produce hydrophobic products and reduce the hydrophilic substances on the mineral surface.

Effect of UV/TiO2 pretreatment on fouling alleviation and mechanisms of fouling development in a cross-flow filtration process using a ceramic UF membrane

In the application of ultrafiltration (UF) for removal of natural organic matter (NOM) from water, membrane fouling has always been considered a big issue. The influence of UV/TiO2 photocatalysis as pretreatment to mitigate cross-flow ceramic UF membrane fouling caused by humic acid (HA) and the involved mechanisms of fouling development were investigated. The characterization of dissolved organic carbon (DOC), specific ultraviolet absorbance (SUVA), excitation-emission matrix (EEM), molecular weight (MW), hydrophilicity, fouling resistance, scanning electron microscopy (SEM) and model fitting using Hermia blocking models were performed. The dominant membrane fouling patterns can be predicated by the initial intermediate pore blocking, transition fouling and the final stage of limited cake growth. With extended UV/TiO2 pretreatment time, a significant reduction of cake filtration coefficients and a slight decrease in pore blocking coefficients were observed. Longer UV/TiO2 pretreatment achieved the remarkable effect of reversible fouling elimination as a result of reaching the final stage of limited cake growth earlier and aggregation forming a porous cake layer by TiO2 particles mixed with more hydrophilic (HPI) and high MW (>50 kDa) humic-like substances. However, photocatalytic pretreatment exhibited a slight effect on the mitigation of irreversible fouling that was mainly dominated by HPI fractions, especially tryptophan-like protein (5–50 kDa) organics attaching to and/or blocking the membrane pores.

Enhanced Sludge Dewaterability and Pathogen Inactivation by Synergistic Effects of Zero-Valent Iron and Ozonation

In this study, the efficiency of the combined zerovalent iron (ZVI) and ozone (O3) treatment at a pH of 2 (acid-ZVI-O3) for simultaneous improvement of sludge dewaterability and pathogen inactivation was investigated. The results showed that the ozone treatment alone deteriorated sludge dewaterability, while the introduction of acid-ZVI into the ozone treatment could significantly enhance the sludge dewaterability. At the optimal conditions with 30 mg O3 g–1 of total solid (TS) and 63 mg ZVI g–1 of TS at a pH of 2, the capillary suction time of conditioned sludge was 1.63 s L g–1 TS, which was much smaller than those of raw sludge (10.45 s L g–1 TS), the single ozonation treated sludge (16.07 s L g–1 TS), and the acid-ZVI-treated sludge (6.98 s L g–1 TS). The acid-ZVI-O3 treatment promoted the generation of hydroxyl radicals and showed synergistic effects in removing key hydrophilic substances which would deteriorate sludge dewaterability, i.e., humic acid-like compounds and soluble microbial byproduct-li...

Biomedical applications of microemulsion through dermal and transdermal route

Microemulsions are thermodynamically stable, transparent, colloidal drug carrier system extensively used by the scientists for effective drug delivery across the skin. It is a spontaneous isotropic mixture of lipophilic and hydrophilic substances stabilized by suitable surfactant and co-surfactant. The easy fabrication, long-term stability, enhanced solubilization, biocompatibility, skin-friendly appearance and affinity for both the hydrophilic and lipophilic drug substances make it superior for skin drug delivery over the other carrier systems. The topical administration of most of the active compounds is impaired by limited skin permeability due to the presence of skin barriers. In this sequence, the microemulsion represents a cost-effective and convenient drug carrier system which successfully delivers the drug to and across the skin. In the present review work, we compiled various attempts made in last 20 years, utilizing the microemulsion for dermal and transdermal delivery of various drugs. The review emphasizes the potency of microemulsion for topical and transdermal drug delivery and its effect on drug permeability.

Comparison of cerebral Open Flow Microperfusion and Microdialysis when sampling small lipophilic and small hydrophilic substances

BackgroundAssessment of drug concentration in the brain interstitial fluid (ISF) is crucial for development of brain active drugs, which are mainly small, lipophilic substances able to cross the blood-brain barrier (BBB). We aimed to compare the applicability of cerebral Open Flow Microperfusion (cOFM) and Microdialysis (MD) to sample the lipophilic substance amitriptyline (AMI), its metabolites Hydroxyamitriptyline (HYA), Nortriptyline (NOR), Amitriptyline-N-Oxide (ANO), deuterated water (D2O) and the hydrophilic substance sodium fluorescein (Naf) in brain ISF. New methodcOFM has been refined to yield increased spatial resolution and performance. Comparison of cOFM and MD and resultsPerformance of cOFM and MD was assessed by in vivo AUC ratios of probe samples (AUCCOFM/AUCMD) and the in vivo relative recovery of D2O (RRvv,D2O). Adsorption of AMI and Naf to MD and cOFM was assessed by the in vitro relative recovery (RRvt) prior to the in vivo experiments. The in vivo AUC ratio of AMI and RRvv,D2O was about two times higher for cOFM than for MD (AUCOFM/AUCMD = 2.0, RRvv,D2O(cOFM)/RRvv,D2O(MD) = 2.1). cOFM detected all investigated AMI metabolites except NOR. MD did not detect HYA, NOR, ANO and Naf. In vitro adsorption of AMI and Naf to the MD membrane was strong (RRvt,AMI = 4.4%, RRvt,Naf = 1.5%) but unspecific adsorption to cOFM was negligibly small (RRvt,AMI = 98% and RRvt,Naf = 98%). ConclusionscOFM showed better performance when sampling AMI and its metabolites, Naf and D2O, and had an about two times higher RRvv,D2O than MD. MD did not detect HYA, NOR, ANO and Naf, most likely due to membrane adsorption.

Biosurfactant rhamnolipid assisted microemulsification of bio-oil components in diesel

ABSTRACTThe use of model bio-oil from pyrolysis biomass as a fuel was improved by forming diesel microemulsion using rhamnolipid (RL) as the surfactant. After microemulsification, synthetic bio-oil components were solubilized in different positions of the microemulsion. Water and some hydrophilic substances were solubilized in the hydrophilic core of the microemulsion, glyoxal, and vanillin in the palisade layer, and guaiacol in the diesel continuous phase. The bio-oil components species and their solubilization positions in the microemulsion fuel system had considerable effect on properties of the fuel, e.g., degradation/combustion characteristics as determined by thermogravimetric analysis.

Characteristic Regions of the Fluorescence Excitation-Emission Matrix (EEM) To Identify Hydrophobic/Hydrophilic Contents of Organic Matter in Membrane Bioreactors.

This study systematically investigated the correlations between fluorescence distributions characterized by the excitation-emission matrix (EEM) and hydrophobic/hydrophilic composition of dissolved organic matter (DOM) in membrane bioreactors (MBRs). On the basis of samples from 10 full-scale MBRs, we performed point-to-point comparisons among different components using an EEM fluorescence quotient (FQ) method and obtained a hydrophobic/hydrophilic fluorophore distribution map via Wilcoxon signed rank test. Hydrophobic acids/bases (HOA/HOB) concentrated in the low-wavelength region [excitation wavelength (Ex) < 235 nm], while hydrophilic substances (HIS) were enriched in the region of Ex > 235 nm [especially with emission wavelength (Em) = 300-360 nm]. Quantitatively, EEM regional contribution to whole wavelength fluorescence was found to significantly correlate with the hydrophobic/hydrophilic proportions of DOM, with Pearson's coefficients of 0.94 and 0.78 ( p < 0.01) for HOA and HIS, respectively. We established a linear regression model showing the HOA proportion as a function of the EEM regional contribution at (Ex, Em) = (200-285, 340-465 nm), with R2 = 0.876, which was validated via leave-one-out cross-validation and Monte Carlo simulation. This study shows a statistically hydrophobicity-dependent fluorescence property across different MBRs, and it might be applied to provide a quick estimation of hydrophobic/hydrophilic composition of DOM in wastewater treatment systems based on EEM monitoring.

Peptide model systems: Correlation between thermophilicity and hydrophilicity.

In recent years, the response of biomolecules to a temperature gradient has been utilized to monitor reactions of biomolecules, but the underlying mechanism is not well understood due to the complexity of the multicomponent system. To identify some underlying principles, we investigate the thermal diffusion of small amide molecules in water systematically. We re-analyze previous measurements of urea and formamide and compare the results with acetamide, N-methylformamide, and N,N-dimethylformamide, amides with a lower hydrophilicity. It turns out that less hydrophilic substances do not show the typical temperature dependence of water soluble macromolecules. Analyzing temperature and concentration dependent measurements using an empirical expression originally derived for nonpolar mixtures, we find that the so-called isotope contribution depends strongly on the hydrophilicity of the solute. This can be qualitatively understood by comparing with molecular dynamic simulations of Lennard-Jones fluids. The hydrophobic/hydrophilic balance also influences the structure in the fluid and with that the thermal expansion coefficient, which correlates with the thermal diffusion coefficient. Furthermore, we observe a clear correlation of the temperature and concentration dependence of the Soret coefficient with the hydrophilicity, which can be quantitatively described by the partition coefficient log P.

Fabrication of Protease-Sensitive and Light-Responsive Microcapsules Encompassed with Single Layer of Gold Nanoparticles by Using Self-Assembly Protein of α-Synuclein.

A bioapplicable cargo delivery system requires the following characteristics of biocompatibility, in vivo stability, and selective cargo release at target sites. We introduce herein the microcapsules enclosed with a single-layered shell of gold nanoparticles (AuNPs) mutually connected by an amyloidogenic protein of α-synuclein (αS). The microcapsules were fabricated by producing oil(chloroform)-in-water Pickering emulsions of the αS-encapsulated AuNPs and subsequent molecular engagement of the outlying αS molecules, leading to formidable β-sheet formation in the presence of chloroform. The wrinkled skin of microcapsules obtained after evaporation of the internal chloroform also reflects robustness of the protein-protein interaction, which was experimentally confirmed by their rheological stability. For the emulsions loaded with rhodamine 6G, their dye release was demonstrated to be controlled by proteases. Along with their photothermal activity, the AuNP-containing microcapsules and their proteolyzed fragments were therefore suggested to be capable of eliminating aberrant cells in the protease-activated pathologically affected areas. Orthogonal cargo loading was also achieved by encapsulating both hydrophobic and hydrophilic substances either directly dissolved in chloroform or prepackaged in inverted micelles, respectively. Microcapsule's functionality was further expanded by localizing quantum dots, magnetic nanoparticles, and antibodies inside or on the surface of the microcapsules. Taken together, these multimodal AuNP microcapsules are suggested to be an ideal cargo carrier system, which could be employed in not only biomedical theranostic applications as they exhibit structural robustness, specific targeting, triggered release, and photothermal activity but also sensor development in general.

Investigations on the relationship between interfacial and single droplet experiments to describe instability mechanisms in double emulsions

Due to their multicomponent structure, water-in-oil-in-water (WOW) double emulsions are of great interest for the encapsulation of hydrophilic substances. Although promising applications are reported, few double emulsion products are available on the market because their stabilization is still challenging. To stabilize all internal interfaces, at least two interfacial active substances (IAS), a lipophilic and a hydrophilic one, have to be added. These IAS can interact with each other at the interfaces and thus might impair the double emulsion stability. Especially the impact of these interactions on the loss of inner water droplets due to coalescence with the outer water phase is largely unknown.In this study, we investigated if interfacial tension measurements can be related to the loss of inner water caused by coalescence. We determined the outer oil in water interfacial tension of a double emulsion, when a hydrophilic or a lipophilic IAS is used individually as well as in combination. Furthermore, the coalescence process between a water droplet encapsulated in oil and an adjacent continuous water phase was observed in single droplet experiments.As model system polyvinyl-alcohol (PVOH) was used as hydrophilic and polyglycerol-polyricinoleate (PGPR) was used as lipophilic IAS. For the sole use of PVOH, the behavior of the coalescence process can be related to the interfacial tension, which was changed by varying the PVOH type. It could be shown that the lower the interfacial tension is, the longer is the time until the coalescence process takes place. In addition, the duration of the coalescence process itself increases by decreasing the interfacial tension for the system under study.In case of the combined use of PVOH and PGPR, the observations differ in dependency on the PVOH type. In case of PVOH with a low hydrophobicity, the simultaneous presence of PGPR caused only a minor change of the coalescence behavior compared to the sole use of PVOH. In case of a PVOH type with higher hydrophobicity, the coalescence behavior changed clearly by the presence of PGPR. However, no correlation to the interfacial tension was found.

Applicability of supercritical fluid chromatography – mass spectrometry to metabolomics. I – Optimization of separation conditions for the simultaneous analysis of hydrophilic and lipophilic substances

The aim of this study was to evaluate the suitability of SFC-MS for the analysis of a wide range of compounds including lipophilic and highly hydrophilic substances (log P values comprised between −6 and 11), for its potential application toward human metabolomics. For this purpose, a generic unified chromatography gradient from 2 to 100% organic modifier in CO2 was systematically applied. In terms of chemistry, the best stationary phases for this application were found to be the Agilent Poroshell HILIC (bare silica) and Macherey-Nagel Nucleoshell HILIC (silica bonded with a zwitterionic ligand). To avoid system overpressure at very high organic modifier proportion, columns of 100 × 3 mm I.D. packed with sub-3 μm superficially porous particles were selected. In terms of organic modifier, a mixture of 95% MeOH and 5% water was selected, with 50 mM ammonium formate and 1 mM ammonium fluoride, to afford good solubility of analytes in the mobile phase, limited retention for the most hydrophilic metabolites and suitable peak shapes of ionizable species. A sample diluent containing 50%ACN/50% water was employed as injection solvent.These conditions were applied to a representative set of metabolites belonging to nucleosides, nucleotides, small organic acids, small bases, sulfated/sulfonated metabolites, poly-alcohols, lipid related substances, quaternary ammonium metabolites, phosphate-based substances, carbohydrates and amino acids. Among all these metabolites, 65% of the compounds were adequately analyzed with excellent peak shape, 23% provided distorted peak shapes, while only 12% were not detected (mostly metabolites having several phosphate or several carboxylic acid groups).

Pore forming channels as a drug delivery system for photodynamic therapy in cancer associated with nanoscintillators.

According to the World Health Organization (WHO), cancer is one of main causes of death worldwide, with 8.2 million people dying from this disease in 2012. Because of this, new forms of treatments or improvement of current treatments are crucial. In this regard, Photodynamic therapy (PDT) has been used to successfully treat cancers that can be easily accessed externally or by fibre-optic endoscopes, such as skin, bladder and esophagus cancers. In addition, this therapy can used alongside radiotherapy and chemotherapy in order to kill cancer cells. The main problem in implementing PDT is penetration of visible light deeper than 10 mm in tissues, due to scattering and absorption by tissue chromophores. Unfortunately, this excludes several internal organs affected by cancer. Another issue in this regard is the use of a selective cancer cell-photosensitizing compound. Nevertheless, several groups have recently developed scintillation nanoparticles, which can be stimulated by X-rays, thereby making this a possible solution for light production in deeper tissues. Alternative approaches have also been developed, such as photosensitizer structure modifications and cell membrane permeabilizing agents. In this context, certain channels lead to transitory plasma membrane permeability changes, such as pannexin, connexin hemmichannels, TRPV1-4 and P2×7, which allow for the non-selective passage of molecules up to 1,000 Da. Herein, we discuss the particular case of the P2×7 receptor-associated pore as a drug delivery system for hydrophilic substances to be applied in PDT, which could also be carried out with other channels. Methylene blue (MB) is a low cost dye used as a prototype photosensitizer, approved for clinical use in several other clinical conditions, as well as photodynamic therapy for fungi infections.

Adsorption of Dissolved Organic Matter with Different Relative Molecular Masses on Inorganic Minerals and Its Influence on Carbamazepine Adsorption Behavior

In this work, sorption experiments were conducted to understand the adsorption characteristics of dissolved organic matter (DOM) of different relative molecular masses on minerals and the effects of their interaction with PPCPs on the adsorption process. This study chose carbamazepine (CBZ) as the target pollutant, quartz sand as the inorganic mineral, and commercial humic acid (HA) as the DOM. We studied the structural characteristics of HA with different relative molecular masses and the impact of their interaction with CBZ on their adsorption based on dialysis experiments and infrared spectroscopy. It was found that large molecular weight fractions of HA, which contain more hydroxyl, aromatic hydrocarbons, and aliphatic hydrocarbons, were mainly hydrophobic substances, while the smaller fractions, containing more alcohols and carboxyl groups, were mainly hydrophilic substances. The combination of HA and CBZ had two major mechanisms, the combination of amino groups of CBZ and polar functional groups in small molecular weight fractions of HA and hydrophobic interactions between hydrophobic groups and aliphatic or/aromatic compounds in large molecular weight HA. The interaction between CBZ and HA resulted in obvious differences in the adsorption of HA or CBZ. When CBZ does not exist, hydrophobic combinations occurred between HA through the hydrophobic components and quartz sand, which also experienced the exchange coordination reaction with the hydroxyl or carboxyl group of HA. In addition, HA adsorbed the aliphatic and hydrophobic macromolecular components. Quartz sand was used to adsorb the large hydrophobic molecules. When CBZ existed, it adsorbed the small molecular weight fractions of HA. The maximum HA adsorption capacity of quartz sand decreased. CBZ could be adsorbed on quartz sand by hydrophobic interaction, van Edward forces, and polarity interactions in the absence of HA. When adding HA, the adsorption increment of carbamazepine on quartz sand was due to the co-adsorption or accumulation of HA and CBZ after their combination.

Solid dispersion of dutasteride using the solvent evaporation method: Approaches to improve dissolution rate and oral bioavailability in rats

The aim of this study was to develop a dutasteride (DUT) solid dispersion (SD) using hydrophilic substances to enhance its dissolution (%) and oral bioavailability in rats. DUT-SD formulations were prepared with various co-polymers using a solvent evaporation method. The physical properties of DUT-SD formulations were confirmed using field emission scanning electron microscopy (FE-SEM), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and attenuated total reflectance Fourier transform infrared (ATR-FT-IR) spectroscopy. The toxicity and oral bioavailability of DUT-SD formulations were evaluated. Tocopheryl polyethylene glycol-1000-succinate (TPGS) was chosen as the solubilizer; and methylene chloride, and Aerosil® 200 or microcrystalline cellulose (MCC) were chosen as the solvent and carrier, respectively, based on a solubility test and pre-dissolution study. The dissolution levels of DUT-SD formulations were 86.3 ± 2.3% (F15) and 95.1 ± 1.9% (F16) after 1 h, which were higher than those of the commercial product, i.e., Avodart® (75.8 ± 1.5%) in 0.1 N HCl containing 1% (w/v) sodium lauryl sulfate (SLS). The F16 formulation was found to be stable, after assessing its dissolution (%) and drug content (%) for 6 months. The DUT-SD formulations resulted in relative bioavailability (BA) values of 126.4% (F15) and 132.1% (F16), which were enhanced compared to that of Avodart®. Dissolution (%) and relative BA values were both increased by hydrogen interaction between TPGS and DUT. This study might contribute to a new formulation (powder) whose oral bioavailability is greater than that of Avodart® (soft capsule), which could facilitate to the use of the SD system during the production process.