Solid-state Characterization Research Articles

Preparation, solubility, and anti-inflammatory effects of a complex of diphenylcyclopropenone/β-cyclodextrin derivatives as the treatment of alopecia areata.

To investigate the preparation of inclusion complexes of diphenylcyclopropenone (DPCP)/β-cyclodextrin (β-CD) derivatives using a three-dimensional (3D) ball mill, and verify the inclusion behavior of the solid dispersion. Additionally, we aimed to investigate the effect of DPCP/β-CDs complex formation on the spleens of male C57BL/6 mice in terms of anti-inflammatory effects. The inclusion complexes of DPCP with β-CD and hydroxypropyl-β-cyclodextrin (HPβCD) were prepared using a 3D ball mill. Powder X-ray diffraction (PXRD) and Fourier-transform infrared spectroscopy (FT-IR) were used to evaluate the solid-state properties. The solubility of the prepared DPCP/β-CD and HPβCD complexes and the intermolecular interaction between DPCP and β-CD derivatives in solution were assessed using 1H nuclear magnetic resonance (NMR). Furthermore, the anti-inflammatory effects of DPCPs in the prepared DPCP/CD complexes were investigated using spleens from male C57BL/6 mice, with measurement of interferon gamma (IFN-γ) secretion as an endpoint. Additionally, the protective effects of each drug on NIH-3T3 cells exposed to ultraviolet (UV) irradiation were examined. Solid-state characterization confirmed the formation of inclusion complexes in the 3D ground mixture (3DGM) (DPCP/β-CD = 1/1) and 3DGM (DPCP/HPβCD = 1/1) complexes through PXRD and IR analysis. The solubility of 3DGM (DPCP/β-CD = 1/1) and 3DGM (DPCP/HPβCD = 1/1) was 17.5μg/mL and 58.4μg/mL, respectively, indicating higher solubility than that of DPCP alone. NMR analysis of 3DGM samples suggested that DPCP/β-CD and DPCP/HPβCD form inclusion complexes at a molar ratio of 1/1 but with different inclusion modes. Regarding the anti-inflammatory activity of DPCP, 3DGM (DPCP/HPβ-CD) showed anti-inflammatory effects at lower doses compared to 3DGM (DPCP/β-CD) in terms of IFN-γ and NIH-3T3 cells injured by UV irradiation. We successfully formed inclusion complexes of DPCP/β-CD and DPCP/HPβCD using the 3D ground mixture method. NMR analysis suggested that DPCP/β-CD and DPCP/HPβCD form inclusion complexes at a molar ratio of 1/1 but with different inclusion modes. The anti-inflammatory activity of DPCP was more pronounced in 3DGM (DPCP/HPβCD) at lower doses compared to that in 3DGM (DPCP/β-CD), indicating that the HPβCD derivatives were more effective in enhancing the anti-inflammatory properties of DPCP.

High solid-state photoluminescence quantum yield of carbon-dot-derived molecular fluorophores for light-emitting devices.

Several recent studies of carbon dots (CDs) synthesized by bottom-up methods under mild conditions have reported the presence of organic molecular fluorophores in CD dispersions. These fluorophores have a tendency to aggregate, and their properties strongly depend on whether they are present in the form of discrete molecules or aggregates. The aggregation becomes more prominent in the solid state, which motivates the study of the properties of the fluorophores associated with CDs in the solid state. Here, we report the solid-state characterization of N4,N11-dimethyldibenzo[a,h]phenazine-4,11-diamine (BPD) - a molecular fluorophore that forms CDs. Discrete BPD molecules show excitation-wavelength-independent photoluminescence (PL) emission in the green wavelength region at ∼520 nm. However, additional blue PL is also observed due to aggregation, making the PL emission significantly broad. For detailed studies, BPD is mixed in different solid matrices, and it is observed that the PL quantum yield (PLQY) of BPD films strongly depends on the concentration of BPD in the solid matrices. Increasing the concentration of BPD results in a considerable decrease in the PLQY. The PLQY of the films with an optimum concentration of BPD is 75.9% and 40.2% in polymethyl methacrylate and polystyrene, respectively. At higher concentrations, these PLQY values decrease to ∼11%. The significant decrease in the PLQY is ascribed to reabsorption and nonradiative exciton decay that is facilitated by BPD aggregation at higher concentrations. Finally, light-emitting devices (LEDs) were fabricated with almost pure white emission color, having CIE (International Commission on Illumination) coordinates of (0.35, 0.37) using BPD in the color-converting layer of blue-pumped LEDs. The device shows a luminous efficiency 3.8 lm W-1 and luminance of 43 331 cd m-2.

Destabilization of Indomethacin-Paracetamol Co-Amorphous Systems by Mechanical Stress.

Using co-amorphous systems (CAMS) has shown promise in addressing the challenges associated with poorly water-soluble drugs. Quench-cooling is a commonly used CAMS preparation method, often followed by grinding or milling to achieve a fine powder that is suitable for subsequent characterization or further down-stream manufacturing. However, the impact of mechanical stress applied to CAMS has received little attention. In this study, the influence of mechanical stress on indomethacin-paracetamol CAMS was investigated. The investigation involved thermal analysis and solid-state characterization across various CAMS mixing ratios and levels of mechanical stress. The study revealed a negative effect of mechanical stress on stability, particularly on the excess components in CAMS. Higher levels of mechanical stress were observed to induce phase separation or recrystallization. Notably, samples at the optimal mixing ratio demonstrated greater resistance to the destabilization caused by mechanical stress. These results showed the significance of careful consideration of processing methods during formulation and the significance of optimizing mixing ratios in CAMS.

Rosuvastatin-loaded solid SMEDDS: an innovative approach for solubility augmentation and improved pharmacodynamic profile

The objectives undertaken in current work were to develop a new solid self-microemulsifying drug delivery system (S-SMEDDS) for poorly water-soluble Rosuvastatin Calcium (RST) and evaluate its antihyperlipidemic activity in rodent model. Solubility assessment in variety of excipients, screening studies and optimization of pseudoternary plots helped in development of liquid SMEDDS. Liquid SMEDDS of RST contained Capryol 90, Kolliphor EL and Transcutol HP as oil phase, surfactant and co-surfactant respectively which were evaluated for release, self-emulsification ability, percentage transmittance and globule size. Florite RE was used as the adsorbent to transform the optimized liquid SMEDDS into non-coherent powder which was then examined for micromeritic properties, solid state characterization and in vitro dissolution studies. It was additionally investigated for antihyperlipidemic activity in rats subjected to high fat diet. Optimized liquid SMEDDS of RST was found to undergo a swift transformation in a microemulsion having globule size in nanometric size range with consistent size distribution. The liquid SMEDDS adsorbed on Florite RE exhibited favorable micromeritic properties and spherical shape. XRD studies indicated amorphization of RST due to its molecular dispersion in S-SMEDDS. Enhanced in vitro rate of dissolution of optimized formulation was observed in comparison to pure drug and commercial product. There was considerable reduction (p < 0.001) in serum levels of total cholesterol (TC), triglycerides (TG), low-density lipoproteins (LDL-C), very low-density lipoproteins (VLDL-C) when S-SMEDDS was administered and increment in high-density lipoproteins (HDL-C) level compared to plain drug suspension. RST S-SMEDDS holds great potential for enhancement of its physiochemical along with biological attributes.

Optimization of Lurasidone HCl-Loaded PLGA Nanoparticles for Intramuscular Delivery: Enhanced Bioavailability, Reduced Dosing Frequency, Pharmacokinetics, and Therapeutic Outcomes.

This study aimed to develop a nanoparticle drug delivery system using poly (lactic-co-glycolic acid) (PLGA) for enhancing the therapeutic efficacy of lurasidone hydrochloride (LH) in treatment of schizophrenia through intramuscular injection. LH-loaded PLGA nanoparticles (LH-PNPs) were prepared using the nanoprecipitation technique and their physicochemical characteristics were assessed. Particle size (PS), zeta potential, morphology, % encapsulation efficiency, % drug loading, drug content, and solid-state properties were analyzed. Stability, in vitro release, and in vivo pharmacokinetic studies were conducted to evaluate the therapeutic efficacy of the developed LH-PNPs. The optimized batch of LH-PNPs exhibited a narrow and uniform PS distribution before and after lyophilization, with sizes of 112.7 ± 1.8 nm and 115.0 ± 1.3 nm, respectively, and a low polydispersity index. The PNPs showed high drug entrapment efficiency, drug loading, and drug content uniformity. Solid-state characterization indicated good stability and compatibility, with a nonamorphous state. The drug release profile demonstrated sustained release behavior. Intramuscular administration of LH-PNPs in rats resulted in a significantly prolonged mean residence time compared with the drug suspension. These findings highlight that intramuscular delivery of the LH-PNP formulation is a promising approach for enhancing the therapeutic efficacy of LH in treatment of schizophrenia.

Study and Characterization of Solid State, Flexible, Wire-Shaped Supercapacitor for Textile Energy Storage Purpose

Flexible and lightweight energy storage devices have become increasingly important for the development of wearable and portable electronics. In this work, we present a novel wire-shape supercapacitor based on carbon nanotube (CNT) yarns and an ionic liquid based polymer electrolyte. The combination of these materials offers high surface area, high conductivity and excellent flexibility, making them a promising candidate for flexible energy storage.The CNT yarns were characterized in a three-electrode configuration by means of electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) either in water-based electrolytes and polymer electrolytes. The polymer electrolytes were prepared by mixing polymers with ionic liquid, which was characterized by thermal analysis and electrochemical measurements.The wire-shape supercapacitor was assembled by coating two CNT yarns with the polymer electrolyte and twisting them together. The devices exhibited high specific capacitance for a waterless system, additionally, they maintained their performance even under extreme deformation: the flexibility of the devices were tested by bending at different angles .Overall, this work highlights the advantages of using CNT yarns and ionic liquid polymer electrolytes for the development of flexible and high-performance supercapacitors. The wire-shape design of the device offers additional advantages for integration into wearable or flexible electronics, providing a promising path towards the development of highly efficient and adaptable energy storage systems.

Controlled synthesis and structure characterization of a new fluconazole polymorph using analytical techniques and multivariate method

In the crystallization and search for higher multicomponent forms of fluconazole (FLZ), a metastable FLZ polymorph (concomitant) that manifests in the same crystallization system and transforms into the stable FLZ form (II) after the lyophilization process was observed. In this report, we demonstrated and showed how this FLZ polymorph 10 (Mw = 306.79 g/mol) of the monoclinic C2 space group was detected and reproduced through a controlled lyophilized experiment, and modeled differentiation between vibrational and absorption modes of FLZ functionalities like C=O, OH, –CH2 and –NH. The FLZ polymorph shows strong O–H···N and weak C−H···X (X = N, and F) hydrogen bond and the presence of pi-pi bond interactions in the overlapping triazole rings. The combination of vibrational spectroscopic techniques (Raman/FT-IR) and principal component analysis (PCA) aid the development of important models for polymorph screening and identification. In addition, X-ray diffraction (powder and single crystal) techniques support the polymorph characterization and structure depiction. The PCA models and X-ray diffraction analyses confirmed the newness of FLZ polymorph 10, and further solid-state characterization using thermal techniques (DSC and TGA) affirmed its uniqueness and novelty. Finally, the thermal stability and solubility studies on the new FLZ polymorph were determined to understand its structure properties and compare these with previously reported polymorphs of FLZ.

Water-Soluble Polyoxometal Clusters of Molybdenum (V) with Pyrazole and Triazole: Synthesis and Study of Cytotoxicity and Antiviral Activity.

Among well-studied and actively developing compounds are polyoxometalates (POMs), which show application in many fields. Extending this class of compounds, we introduce a new subclass of polyoxometal clusters (POMCs) [Mo12O28(μ-L)8]4- (L = pyrazolate (pz) or triazolate (1,2,3-trz or 1,2,4-trz)), structurally similar to POM, but containing binuclear Mo2O4 clusters linked by bridging oxo- and organic ligands. The complexes obtained by ampoule synthesis from the binuclear cluster [Mo2O4(C2O4)2(H2O)2]2- in a melt of an organic ligand are soluble and stable in aqueous solutions. In addition to the detailed characterization in solid state and in aqueous solution, the biological properties of the compounds on normal and cancer cells were investigated, and antiviral activity against influenza A virus (subtype H5N1) was demonstrated.

Fabrication and in vitro characterization of delafloxacin-laden electrosprayed hydroxypropyl cellulose nanoparticulated solid dispersions for enhanced aqueous solubility and release rate of the drug

With the aim of fabricating and characterizing an optimized drug delivery system (DDS) for an effective administration of poorly water-soluble delafloxacin (DFX) via the oral route, several formulations of delafloxacin-laden solid dispersions (SD) were prepared employing the solvent-evaporation and electrospraying techniques concomitantly. Solubility and release rate of the drug in the SD were assessed. Solid-state characterization was performed via the X-ray diffraction (PXRD) and differential scanning calorimetric (DSC) analyses, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopic (FTIR) analysis. Amongst the prepared SD, an optimized formulation consisting of DFX, HPC, and SLS at the weight ratio of (1/8/0.2) showed about 9-fold higher solubility and 13-fold faster release rate of delafloxacin as compared to delafloxacin plain drug powder (DPDP). The drug existed in the amorphous form in the spherical particles and had no covalent interaction with any of the excipients. Thus, this optimized formulation might be a useful DDS for an effective administration of DFX.

Expanding the Transuranic Metal-Organic Framework Portfolio: The Optical Properties of Americium(III) MOF-76.

Reported is the synthesis, crystal structure, and solid-state characterization of a new americium containing metal-organic framework (MOF), [Am(C9H3O6)(H2O)], MOF-76(Am). This material is constructed from Am3+ metal centers and 1,3,5-tricarboxylic acid (BTC) ligands, forming a porous three-dimensional framework that is isostructural with several known trivalent lanthanide (Ln) analogs (e.g., Ce, Nd, and Sm-Lu). The Am3+ ions have seven coordinates and assume a distorted, capped trigonal prismatic geometry with C1 symmetry. The Am3+-O bonds were studied via infrared spectroscopy and compared to several MOF-76(Ln) analogs, where Ln = Nd3+, Eu3+, Tb3+, and Ho3+. The results show that the strength of the ligand carboxylate stretching and bending modes increase with Nd3+ < Eu3+ < Am3+ < Tb3+ < Ho3+, suggesting the metal-oxygen bonds are predominantly ionic. Optical absorbance spectroscopy measurements reveal strong f-f transitions; some exhibit pronounced crystal field splitting. The photoluminescence spectrum contains weak Am3+-based emission that is achieved through direct and indirect metal center excitation. The weak emissive behavior is somewhat surprising given that ligand-to-metal resonance energy transfer is efficient in the isoelectronic Eu3+ (4f6) and related Tb3+ (4f8) analogs. The optical properties were explored further within a series of heterometallic MOF-76(Tb1-xAmx) (x = 0.8, 0.2, and 0.1) samples, and the results reveal enhanced Am3+ photoluminescence.

The inherent AIE feature revealed the drug molecular state in cyclodextrin metal–organic framework for enhanced stability and absorption

The amorphous form of a drug can greatly improve the solubility and rates of dissolution for enhancing oral bioavailability. However, amorphous drugs tend to crystallize thus negating their solubility advantages. Here, we use a nanoconfinement strategy to prevent the crystallization of amorphous solids by loading the poorly soluble drug indomethacin (IMC) into a porous γ-cyclodextrin-based metal–organic framework (CD-MOF). The inherent aggregation-induced emission (AIE) property of IMC was successfully applied as a sensitive fluorescence imaging tool to visualize its molecular state in the solid form. A distinct high-energy, non-aggregated molecular state of IMC in CD-MOF was revealed by the AIE turn-off phenomenon together with other solid-state characterization methods. The IMC@CD-MOF exhibited excellent physical stability even when stored at high temperature or humidity. The high supersaturated drug solutions were immediately generated and maintained during the dissolution of IMC@CD-MOF, resulting in a great enhancement of in vivo bioavailability. The inherent AIE feature of drugs can facilitate the understanding of the structure–property relationship in complex delivery systems, which is essential for the design and optimization of drug carriers with desired stability and biopharmaceutical performance.

Supercritical fluid technology as a strategy for nifedipine solid dispersions formulation: In vitro and in vivo evaluation

Supercritical fluid technology (SFT) is an insufficiently investigated approach for the production of solid dispersions, it is environmentally acceptable and has a high potential for application in the pharmaceutical industry. The aim of this work was to formulate and characterize nifedipine solid dispersions (SDs) produced by the SFT and compare the results with ones obtained by the classical solvent based kneading method. The following in vitro tests were conducted: assay and yield, solvent residues, solid state characterization (FTIR, DSC, XRD), flowability, hygroscopicity, solubility, dissolution and stability. Additionally, bioavailability was examined on an animal model (Wistar rats). The formulation selection for in vivo study was performed using the multilevel categoric experimental design and the health risk assessment. Solid state characterization revealed that formulation obtained by the SFT method and higher ratio of polymer (1:5) have had nifedipine in completely amorphous form. Polymer ratio and method of SDs preparation do influence the investigation characteristics. Dissolution rate was fastest in SDs prepared by the SFT and higher polymer ration (1:5). In vivo data of selected SDs prepared by the kneading (ratio 1:1) and the SFT (ratio 1:5) showed alteration in pharmacokinetic profile after i.v. and p.o. application.

Reduction and precipitation of chromium(VI) using a palladized membrane biofilm reactor

H2-driven reduction of hexavalent chromium (Cr(VI)) using precious-metal catalysts is promising, but its implementation in water treatment has been restricted by poor H2-transfer efficiency and high catalyst loss. We investigated the reduction of Cr(VI) through hydrogenation catalyzed by elemental-palladium nanoparticles (PdNPs) generated in-situ within biofilm of a membrane biofilm reactor (MBfR), creating a Pd-MBfR. Experiments were conducted using a Pd-MBfR and a non-Pd MBfR. The Pd-MBfR achieved Cr(VI) (1000 μg L−1) reduction of >99% and reduced the concentration of total Cr to below 50 μg L−1, much lower than the total Cr concentration in the non-Pd MBfR effluent (290 μg L−1). The Pd-MBfR also had a lower concentration of dissolved organic compounds compared to the non-Pd MBfR, which minimized the formation of soluble organo-Cr(III) complexes and promoted precipitation of Cr(OH)3. Solid-state characterizations documented deposition of Cr(OH)3 as the product of Cr(VI) reduction in the Pd-MBfR. Metagenomic analyses revealed that the addition and reduction of Cr(VI) had minimal impact on the microbial community (dominated by Dechloromonas) and functional genes in the biofilm of the Pd-MBfR, since the PdNP-catalyzed reduction process was rapid. This study documented efficient Cr(VI) reduction and precipitation of Cr(OH)3 by the Pd-MBfR technology.

Design, development and characterization of the Apremilast and Indomethacin coamorphous system

Our main aim in the present investigation, preparation of a drug-drug coamorphous system (CAM) of Apremilast (APR) and Indomethacin (INDO) to improve physiochemical properties, solubility and stability. Various solid-state characterization techniques were used to characterize the prepared APR-INDO CAM system. Single Tg in DSC, hallow pattern in PXRD, and absence of birefringence in PLM indicate the formation of the CAM system between APR and INDO. The molecular level interaction in the CAM system was studied using ATR-FTIR and 1H NMR. The molecular modeling-based analysis was performed to understand intermolecular interactions in the CAM system. Solubility and dissolution studies were carried out to investigate the benefits of the CAM system over its crystalline and amorphous forms of APR and INDO. The CAM system was stable for five months under 40 ± 2 °C and 75 ± 5 % RH. In the permeation study, CAM system had an 8.19-fold higher flux for APR and a 5.83-fold higher flux for INDO compared to crystalline APR and INDO, respectively. The APR-INDO CAM system showed anti-psoriatic and anti-melanogenic activity from the molecular docking results. As a result, we determined that the developed CAM-based supersaturated system has improved physicochemical properties and physical stability.

Redox regulation of layered Fe-Cr hydroxides during Cr(VI) reduction by sulfate green rust: The overlooked electron conductivity and reactivity of Fe(III)-Cr(III) residues

In this study, unique layered Fe(III)-Cr(III) oxides were formed during the Cr(VI) removal by sulfate green rust (GRSO4). Solid state characterization confirmed that the hexagonal plate and layered structure of GRSO4 remained after fast reduction of Cr(VI). Then, sodium dithionite was further employed to reduce the Fe(III) to Fe(II) in these layered Fe(III)-Cr(III) oxides, enabling stable Fe(II)/Fe(III) cycle in the hexagonal plates. As the Fe(II) content increased in the layered Fe(III)-Cr(III) oxides, there was no significant Fe(II) and Cr(III) release into the solution and the GR-like plate remained intact, indicating that this hexagonal layer Fe-Cr oxides has stable structure during the reduction of Fe(III). Interestingly, better crystallinity was observed at higher Fe(III) reduction rate, and the layered metal oxide structure was confirmed with a basal spacing of 0.935 nm when ∼ 100 % of Fe(III) was reduced to Fe(II). Multiple treatment cycles experiment demonstrated that Cr(III) loading on the layered Fe(III)-Cr(III) oxides could be increased in the following 6 runs of Fe(II)/Fe(III) redox cycle. This study provides new evidence to confirm the electron conductivity and redox reactivity of the Fe(III)-Cr(III) residues under ambient condition, which might help to formulate novel strategies for elimination of Cr(VI) or related heavy metals.

Catalyst-Free Transfer Hydrogenation from Amine-Borane Small Oligomers.

Amine-borane dimers and oligomers with varied steric and electronic profiles were prepared via capping agent-controlled AA/BB polycondensations. They were used for transfer hydrogenations to aldehydes, ketones, imines as well as electron-poor alkene/alkyne moieties. The amine-borane Lewis-paired oligomers and the congested bis(amine-borane)s provided the highest yields. This was likely helped by facilitated dissociation (oligomers) or H-bond assistance. In the case of the oligomers, the second equivalent of H2 present was also engaged in the reaction. Solid-state NMR characterization provides evidence that the boron-containing materials obtained after transfer dehydrogenation are highly similar to those obtained from thermal dehydrogenation. The oligomers bridge the gap between simple amine-borane molecular reductants and the poly-amine-boranes and provide a full picture of the reactivity changes at the different scales.

Investigation of drug-polymer miscibility and design of ternary solid dispersions for oral bioavailability enhancement by Hot Melt Extrusion

The present investigation aimed to enhance the oral bioavailability of the poorly water-s Glibenclamide (GLB) using amorphous solid dispersions (ASD) with various polymers. The drug-polymer miscibility was predicted using in-silico molecular dynamics simulation, Hansen solubility parameter, Flory-Huggins theory, and Gibb’s free energy calculation. To enhance the solubility further, the effervescence amorphous solid dispersions (ESD) technique was included. The solid dispersions (SDs) were initially prepared using the solvent evaporation method. The polymers that enhanced the solubility were optimized by the Design of Experiments (DoE) approach and Hot Melt Extruder (HME) technique. The optimized formulation were subjected to various solid and liquid state characterizations. The XRD and DSC study confirmed conversion into the amorphous form, and hydrogen bonding between the drug and polymer was confirmed by FTIR and 1H NMR. The morphology was assessed by SEM study. The optimized formulation showed enhanced solubility and dissolution data. The optimized formulation remained stable at the accelerated conditions for six months. The optimized formulation subjected to the pre-clinical pharmacokinetic and pharmacodynamics study showed a better pharmacokinetics profile of the drug and enhanced pharmacological activity. Introducing the effervescent technique to the conventional ASD technique helped to enhance the physicochemical properties with improved pharmacological action.

Development and Evaluation of Amorphous Solid Dispersion of Riluzole with PBPK Model to Simulate the Pharmacokinetic Profile.

In the current work, screening of polymers viz. polyacrylic acid (PAA), polyvinyl pyrrolidone vinyl acetate (PVP VA), and hydroxypropyl methyl cellulose acetate succinate (HPMC AS) based on drug-polymer interaction and wetting property was done for the production of a stable amorphous solid dispersion (ASD) of a poorly water-soluble drug Riluzole (RLZ). PAA showed maximum interaction and wetting property hence, was selected for further studies. Solid state characterization studies confirmed the formation of ASD with PAA. Saturation solubility, dissolution profile, and in vivo pharmacokinetic data of the ASD formulation were generated in rats against its marketed tablet Rilutor. The RLZ:PAA ASD showed exponential enhancement in the dissolution of RLZ. Predicted and observed pharmacokinetic data in rats showed enhanced area under curve (AUC) and Cmax in plasma and brain with respect to Rilutor. Furthermore, a physiologically based pharmacokinetic (PBPK) model of rats for Rilutor and RLZ ASD was developed and then extrapolated to humans where physiological parameters were changed along with a biochemical parameter. The partition coefficient was kept similar in both species. The model was used to predict different exposure scenarios, and the simulated data was compared with observed data points. The PBPK model simulated Cmax and AUC was within two times the experimental data for plasma and brain. The Cmax and AUC in the brain increased with ASD compared to Rilutor for humans showing its potential in improving its biopharmaceutical performance and hence enhanced therapeutic efficacy. The model can predict the RLZ concentration in multiple compartments including plasma and liver.

Evaluation of the effect of physical and chemical factors in the recovery of Cu, Pb and Fe from waste PCB through acid leaching

Electronic waste recycling is a strategy that contributes to implement a circular economy model which include reuse, component and raw material recovery and minimum final deposition. Given the importance of reincorporating the components of electronic devices into the productive chain and a correct recovery for some hazardous metals such as lead contained in such residues. This study is focused on the effect of maximum available content (MAC) of metal, sulfuric acid initial concentration, agitation velocity, and oxidising agent on the recovery of copper, lead and iron from electronic waste through acid leaching. A solid-state characterization before and after treatment and electrochemical analysis was carried out to analyse MCA effects and surface chemistry. It was found that sub-millimetric particles show a better available extraction percentage in case of copper and iron, being opposite for lead. Presence of hydrogen peroxide enhance the extraction efficiency, however, this cause iron and lead precipitation, therefore it is inefficient for metals recovery as well as for reagent consumption. The presence of calcium salts reacts producing gypsum, which reduces the extraction yield of copper at particle size below 250 μm.

Three pesticide-pesticide eutectic systems of boscalid: Mechanochemical preparation, characterization and mechanism analysis

Preparation of eutectic mixture is considered to be an efficient means to improve physical and chemical properties in many fields. In this work, three pesticide-pesticide eutectic systems of boscalid with diniconazole, uniconazole and 3,6-dichloropicolinic acid were prepared by mechanochemical method. The formation of eutectic mixtures was identified by differential scanning calorimetry and powder X-ray diffraction characterizations. From the constructed solid–liquid phase diagrams, it is discovered that these eutectic systems could form a eutectic when the molar fraction of boscalid is 0.500. In addition, all eutectic temperatures are more than 29 K lower than the higher melting points of the constituents in the systems, which eliminates the issue of the poor thermal stability of constituents and enables the treatment of them using melting-based operations. Ideal model and COSMO-RS theory also calculate these solid–liquid phase diagrams relatively accurately, and the calculated activity coefficient values prove that these systems do not deviate significantly from the ideal state. The distinct non-ideality at the eutectic composition of the three systems also suggests that the interactions of the three coformers and the boscalid differ. The formation of eutectic mixtures was further confirmed by other solid state characterizations including mid-infrared spectroscopy, Raman spectroscopy and etc. The accelerated stability test indicates the good stability of the three eutectic mixtures. Furthermore, the water solubility study suggests the boscalid in the eutectic systems has a higher solubility than raw boscalid. By using COSMO-RS modelling, the most typical homo/hetero-molecular complexes of these pesticides were obtained and analyzed. Based on the trend of affinity characterized by the Gibbs free energy of the generation of molecular complexes, it could be inferred that eutectic point could be viewed as the state for which affinity of hetero-molecular complexes is greatest. The affinity of hetero-molecular complexes also presents the interaction between boscalid and 3,6-dichloropicolinic acid is greater than the other two pesticides at the eutectic point. Furthermore, the calculated solvation free energies document the intermolecular interaction plays an important role in stabilizing the three eutectic systems. These eutectic systems solve the problem that the three coformers are unsuitable for melting-based procedures and improve the solubility, making them potential options for future pesticide formulation development.