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Green rusts (GR) are mixed-valence iron (Fe) hydroxides which form in reducing redox environments like riparian and wetland soils and shallow groundwater. In these environments, silicon (Si) can influence Fe oxides' chemical and physical properties but its role in GR formation and subsequent oxidative transformation have not been studied starting at initial nucleation. Green rust sulfate [GR(SO4)] and green rust carbonate [GR(CO3)] were both coprecipitated from salts by base titration in increasing % mol Si (0, 1, 10, and 50). The minerals were characterized before and after rapid (24 h) aqueous air-oxidation by x-ray diffraction (XRD), scanning electron microscopy (SEM), Fe extended x-ray absorption fine structure spectroscopy (EXAFS), and N2-BET surface area. Results showed that only GR(SO4) or GR(CO3) was formed at every tested Si concentration. Increasing % mol Si caused decreased plate size and increased surface area in GR(CO3) but not GR(SO4). GR plate basal thickness was not changed at any condition indicating a lack of Si interlayering. Air oxidation of GR(SO4) at all % mol Si contents transformed by dissolution and reprecipitation into lepidocrocite and goethite, favoring ferrihydrite with higher % Si content. Air oxidation of GR(CO3) transformed into magnetite and goethite but increasing Si caused GR to oxidize while retaining its hexagonal plate structure via solid-state oxidation. Our results indicate that Si has the potential to cause GR to form in smaller particles and upon air oxidation, Si can either stabilize the plate structure or alter transformation to ferrihydrite. [ABSTRACT FROM AUTHOR]

Regarding potential high temperature applications of materials based on the ternary Al2O3-YAG-ZrO2 (AYZ) eutectic system for turbine blades, their environmental behaviour has to be evaluated in near-service conditions. CMAS attack is one of the phenomena limiting lifetime of ceramic E/TBC coatings for aircraft engines. The present study reports an assessment of the reactivity of AYZ eutectic material facing with two molten CMAS. The effect of test duration (up to 500 h), CMAS composition (with or without Fe2O3), microstructure (interlamellar distance), temperature (1250 and 1350 °C) as well as thermal cycling resistance were investigated. Results evidenced that the interaction of CMAS with AYZ eutectic ceramic was limited regardless of the microstructure. No infiltration of molten CMAS within the eutectic ceramic nor mechanical rupture between CMAS and AYZ was observed. The dissolution of AYZ leads to the rapid formation of anorthite with the CMAS components that hinders further reactions. The inward growth of MgAl2O4 spinel in place of the Al2O3 network occurs in accordance with the thermodynamic available data and without any effect on AYZ integrity. [ABSTRACT FROM AUTHOR]

Quantitative analyses of the species composition and abundance of benthic foraminifers in surface sediments along a submeridional profile in the northeastern East Siberian Sea have revealed three assemblages associated with the middle–outer shelf and upper and middle continental slope. The maximum abundance of "living" benthic foraminifers is found near the shelf break, which is possibly related to enhanced sea surface bioproductivity. Active dissolution of calcareous microfossils has been detected in the shelf area whereas preservation of calcareous tests becomes better with depth. Some micropaleontological and grain-size data indirectly point to the development of compensatory currents on the middle–outer shelf in the East Siberian Sea. [ABSTRACT FROM AUTHOR]

The article presents a kinetic model describing the lead vapor oxidation in the vapor bubble volume to produce lead oxide and hydrogen with their subsequent dissolution in the lead melt volume. The model is implemented in the approximation of homogeneous distribution of reagents and oxidation reaction products in the bubble volume. An analytical solution for stationary oxidation conditions is obtained. It is shown that vapor bubbles in the lead melt volume are a sort of chemical "microreactors" producing lead oxide and hydrogen, which subsequently dissolve in the melt volume. However, such hydrogen generation mechanism does not pose any threat for the primary coolant circuit of fast lead cooled reactors in terms of hydrogen accumulation and explosion hazard in view of essentially low intensity of the hydrogen generation source. The article presents the results of water to hydrogen conversion assessments carried out with the use of a homogeneous kinetic model for interaction of water vapor with lead vapor in the vapor bubble volume. The model incorporates mechanisms governing lead evaporation into the bubble volume, oxidation of lead vapor as it interacts with water vapor in the bubble volume, and dissolution of reaction products in the lead melt surrounding the bubble. One more important result of equilibrium thermodynamic computations is connected with a possible change in the composition of iron oxides in the melt after the injection of water from the steam generator leak into the melt. The ingress of water into the lead melt may cause a change in the composition of iron oxides, thereby increasing the fraction of hematite and decreasing the fraction of magnetite. This may entail a change in the composition of the protective oxide film on the structural steel surface to make it more brittle. [ABSTRACT FROM AUTHOR]

The present study was aimed to ameliorate the issue of solubility and thereby, bioavailability of ketoprofen, a BCS Class II drug. The sustained release matrix tablets (MT) were prepared using surfactant-assisted wet granulation (SAWG) with 1–5% of different surfactants. The tablet characteristics were within the compendial limits. The selected sustained release-compliant matrix tablet formulation containing granules prepared using 3% Soluplus® (MT2) released the drug by swelling-erosion. In human volunteers, MT2 attained the maximum plasma concentration (Cmax) of 5.72µg /ml ± 0.30 h, time to Cmax (Tmax) of 5.56 ± 0.30 h and maintained the plasma concentration above its minimum effective concentration (MEC), 0.7 µg.ml−1 till 24h. A control formulation, prepared from granules without surfactant (MT16), promptly attained Cmax of 9.62 ± 0.76 µg/ml within 1h but rapidly declined to below MEC in 8h. Area under the curve from initial point to infinity (AUC0-∞) of MT2 (78.65 ± 7.64 µg.h.ml−1) was 2.29 folds higher than 34.39 ± 3.06 µg.h.ml−1 of MT16. With decreased Cmax, increased AUC0-∞, delayed Tmax and retained ketoprofen concentration above MEC for longer time, MT2 corresponded with the in-vitro sustained drug release characteristic. There is a likelihood of administration of once-a-day single dose of MT2 without plasma fluctuations, expected from two doses of MT16. SAWG helped developing a swellable-erodible sustained release matrix tablet formulation of ketoprofen with the desired biopharmaceutical and pharmacokinetics properties, merely by addition of Soluplus® in granules and without incorporation of any special ingredients or the major manipulation of the formulative ingredients in the formulation. [ABSTRACT FROM AUTHOR]

The focus of current studies was to fabricate dose flexible printlets of dapsone (DDS) for pediatric patients by selective laser sintering (SLS) 3D printing method, and evaluate its physicochemical, patient in-use stability, and pharmacokinetic attributes. Eight formulations were fabricated using Kollicoat® IR, Eudragit® L-100-55 and StarCap®as excipients and evaluated for hardness, disintegration, dissolution, amorphous phase by differential scanning calorimetry and X-ray powder diffraction, in-use stability at 30 oC/75% RH for a month, and pharmacokinetic study in Sprague Dawley rats. The hardness, and disintegration of the printlets varied from 2.6±1.0 (F4) to 7.7±0.9 (F3) N and 2.0±0.4 (F2) to 7.6±0.6 (F3) sec, respectively. The drug was partially present as an amorphous form in the printlets. The drug was completely (>85%) dissolved in 20 min. No change in drug form or dissolution extent was observed after storage at in use condition. Pharmacokinetic profiles of both formulations (tablets and printlets) were almost superimposable with no statistical difference in pharmacokinetic parameters (Tmax, Cmax, and AUC0-¥)between formulations (p>0.05). Values of EC50 (half maximal effective concentration) and EC90 (maximal concentration inducing 90% maximal response) were 0.50±0.15 and 1.32±0.26 mM, 0.41±0.06 and 1.11±0.21, and 0.42±0.13 and 1.36±0.19 mM for DDS, printlet and tablet formulations, respectively, and differences were statistically insignificant (p>0.05). In conclusion, tablet and printlet formulations are expected to be clinical similar, thus clinically interchangeable. [ABSTRACT FROM AUTHOR]

The intricate process of protein binding orchestrates crucial drug interactions within the bloodstream, facilitating the formation of soluble complexes. This research endeavours to improve the dissolution and oral bioavailability of Rifampicin (RMP) by strategically manipulating drug-protein binding dynamics and the hydrophobic characteristics of human serum albumin (HSA). Various precipitation techniques leveraging methanol, ammonium sulfate, and heat treatment were meticulously employed to tailor the properties of colloidal albumin (HSA NPs). The resultant complexes underwent comprehensive characterization encompassing evaluations of hydrophobicity, size distribution, surface charge, and structural analyses through FTIR, TG-DSC, XRD, and morphological examinations. The findings revealed a significant binding affinity of 78.07 ± 6.6% with native albumin, aligning with prior research. Notably, the complex RMP-HSA NPs-M13, synthesized via the methanolic precipitation method, exhibited the most substantial complexation, achieving a remarkable 3.5-fold increase, followed by the ammonium sulfate (twofold) and heat treatment (1.07-fold) methods in comparison to native albumin binding. The gastric simulated media exhibited accelerated drug release kinetics, with maximal dissolution achieved within two hours, contrasting with the prolonged release observed under intestinal pH conditions. These findings translated into significant improvements in drug permeation, as evidenced by pharmacokinetic profiles demonstrating elevated Cmax, AUC, t1/2, and MRT values for RMP-HSA NPs-M13 compared to free RMP. In summary, this innovative approach underscores the potential of precipitation methods in engineering stable colloidal carrier systems tailored to enhance the oral bioavailability of poorly soluble drugs, offering a pragmatic and scalable alternative to conventional surfactants, polymers, or high-energy methods for complex formation and production. Highlights: Colloidal albumin produced by methanol exhibits superior physiochemical and pharmaceutical performance. Albumin-Rifampicin conjugates are thought to be a potential method for improving drug release and oral bioavailability. Albumin-Rifampicin complex shows better pharmacokinetic characteristics compared to free Rifampicin. [ABSTRACT FROM AUTHOR]

Background: Herbal medicines used for male sexual disorders are widespread across the globe and have been noted as likely candidates for adulteration. To assure access to safe and quality herbal products, this study aimed at sampling some herbal capsules indicated for male vitality for quality analytical checks. Methods: Herbal capsules sampled from two regions were subjected to physicochemical assessment, using pharmacopeial and regulatory standards. Microbial quality analysis was also performed on the selected products. A validated HPLC method for simultaneous analysis of sildenafil citrate and tadalafil was used to detect and quantify the possible presence of phosphodiesterase inhibitors in the selected products. Results: Out of a total of 57 herbal capsules, 19 were indicated for male sexual related illnesses of which only 8 fulfilled the inclusion criteria of being used exclusively for male vitality. The majority (62.5%) of the herbal products failed the weight uniformity test but all of them disintegrated within the acceptable limit of 30 min. The moisture and heavy metal contents were within limits of acceptability. Majority (87.5%) of the herbal products failed the test for the aerobic bacteria count; however, none of the isolated bacteria was pathogenic. Sildenafil citrate was detected in the majority (87.5%) of the herbal products in concentrations of 0.98–33.95 mg/g. Two products contained both sildenafil and tadalafil. High batch-to-batch variability was recorded in some physicochemical parameters and pharmaceutical adulterants. Conclusion: High incidence of quality fails and adulteration of herbal capsules for sexual disorders observed means there is a real risk of unintended dosing with phosphodiesterase inhibitors. This represents a public health issue and necessitates tighter monitoring of production standards by the regulator. [ABSTRACT FROM AUTHOR]

Three new binary acidic deep eutectic solvents (DESs) were derived from tetrabutylammonium bromide (TBAB) as a hydrogen bond acceptor (HBA) coupled with azelaic acid (AzA), benzilic acid (BeA) and boric acid (BoA) as hydrogen bond donors (HBD). In order to draw the complete phase diagram and find the molar ratios in which the DESs are formed, HBA and HBDs were mixed together in the full range of molar ratios and their thermal behavior (by differential scanning calorimetry method) and stability were investigated. The activity coefficient models including Wilson, NRTL and regular solution were applied to correlate the measured solid–liquid equilibrium data. FT–IR and NMR analysis were used to investigate the chemical structures, occurrence the hydrogen bond formation between the DESs constituents and purity of the prepared DESs. Physicochemical properties of these DESs including melting point, density, and speed of sound, conductivity and refractive index were measured at different temperatures. The performance of these new DESs were successfully evaluated for the dissolution of four metal oxides including PbO, CuO, Fe2O3 and ZnO and the obtained solubility values were compared with the reported literature data. [ABSTRACT FROM AUTHOR]

This study investigates the dissolution characteristics of a stalactite from Küpeli Cave in southern Turkey, employing a holistic approach that includes macroscopic and microscopic analyses alongside advanced techniques such as X-ray diffraction, and scanning electron microscopy. The studied stalactite exhibits distinct morphological features: an upper main body with visible growth layers and dissolution channels, and a lower pendant made of solid sparite calcite crystals. The outer surface of the main body exhibits partial dissolution corrosion and protrusion-like structures resulting from channel infilling resisting corrosion. Notably, the pendant section of the stalactite remains largely unaffected by the dissolution, preserving its original structure. The longitudinal cross-section of the main body reveals dissolution channels along the growth layer's surface, partially filled with calcite cement. Secondary channels branch off the main channels, some connected to the outer surface at certain points, allowing cave water to enter. The dissolution processes also lead to microscale changes in the primary microfabrics, including the widening of intercrystalline pores, microperforated zones, microchannels, rhombohedral microcrystalline blocks, spiky calcite, pits, and abiotic micritization. The recurring dissolution features inside the stalactite indicate synchronous dissolution during stalactite formation, where the precipitation/dissolution conditions repeat cyclically. Dissolution typically occurs during the rainy season when cave water is unsaturated with calcite, otherwise, calcite precipitates, forming overgrowth layers and/or cement. [ABSTRACT FROM AUTHOR]

In this study, the contact effects between mesophile bacteria and minerals were observed to enhance the bioleaching kinetics, which demonstrated that the adsorption of bacteria to mineral surfaces could improve the dissolution of arsenic and copper. The microstructure results also demonstrated that after the contact bioleaching, residue surfaces were rougher and with more corrosion bars and pits. Compared to contact oxidation approach, ferric ions, acting as the only oxidants in the non-contact bioleaching process, play a more important role in the copper extraction and arsenic dissolution, which is consistent with the previous works about indirect leaching mechanism. Due to the presence of various mesophiles in the contact oxidation, their activities and corresponding preferences for energy sources influenced by temperature were observed, causing differences in the sulfides' dissolution: ferrous ions were inclined to be oxidized biologically at 30 °C, whereas sulfide minerals, including enargite, were preferentially oxidized at 45 °C. [ABSTRACT FROM AUTHOR]

CoSe is one of the chalcogenides attracting much attention due to its excellent hydrogen evolution reaction (HER) activity and low price. However, CoSe prepared by electrodeposition generally shows lower HER activity and stability under acidic conditions than those prepared by other methods. In this study, it was assumed that the cause of the low HER performance of electrodeposited CoSe is mainly due to the dissolution of Co and Se, which do not form a stable alloy, and annealing of electrodeposited CoSe was introduced to demonstrate this. We compared the HER activity and stability of non-annealed and annealed CoSe in 0.5 M H2SO4 electrolyte and investigated the dissolution behaviors of the two catalysts during HER. As a result, it was found that Co and Se, which did not form a stoichiometric CoSe2 alloy, were found to be vulnerable in acidic conditions. The annealing induced additional CoSe2 formation, improving the HER activity and stability of electrodeposited CoSe. The annealed CoSe exhibited an overpotential of 175 mV at 10 mA cm−2, 27 mV lower than that of non-annealed one, and was stable for 48 h at 10 mA cm−2. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the physicochemical interactions between concomitantly administered anti-malarial and antiretroviral drugs. Methods: The physicochemical interactions between antimalarial fixed dose combination i.e., Artemether (A) and Lumefantrine (L) with Nevirapine (N) or Efavirenz (E) were investigated separately. The physical mixtures (ALE and ALN) were subjected to solubility, pH shift dissolution (in phosphate and biorelevant media), solid-state characterisation and ex-vivo permeability studies. Results: For Artemether-Lumefantrine + Efavirenz (ALE) system, the pH shift dissolution study revealed that artemether concentration in mixture decreased to half of its pure drug dissolution in the presence of Lumefantrine and Efavirenz. Further, solid state characterisation confirms the in-situ conversion of artemether into amorphous form in the presence of Lumefantrine and Efavirenz. Similarly, in the ex-vivo everted gut sac permeability study, permeability of Artemether in the presence of Lumefantrine and Efavirenz decreased by half compared to the permeability of Artemether alone, due to physicochemical interactions. For Artemether-Lumefantrine + Nevirapine (ALN) system, there was no significant change in the dissolution of artemether from the combination and alone. However, the permeability of Artemether was decreased to half of its pure drug permeability in the presence of Lumefantrine and Nevirapine, which may be attributed to the inducation of Cytochrome P450 3A4 and P-glycoprotein enzyme by Nevirapine. Conclusion: The dissolution and permeability of Artemether in the mixtures were reduced to half of its pure drug dissolution and permeability in the presence of antiretroviral drugs due to physicochemical interactions, which may lead to a decrease in bioavailability. This study’s results reveal concomitant administration of these drugs could lead to treatment failure due to physicochemical interactions. [ABSTRACT FROM AUTHOR]

Granulation is the critical process for the pharmaceutical development of poorly water-soluble drug products. Poorly formulated products have challenges in dissolution and bioequivalence studies. Rivaroxaban (RXB) is a poorly soluble drug and has 66% fasting bioavailability at a high strength of 20 mg. Establishing the bioequivalence between test and reference products for high strength requires comparative dissolution profiles and bioequivalence. Improper granulation products and the rest of the batches failed in virtual bioequivalence. The present study provided insight into the optimization of the wet granulation process for manufacturing RXB generic immediate-release tablets using PBPK modeling and simulations. Furthermore, PBPK models are not only useful for formulation optimization but also for process optimization during pharmaceutical product development. [ABSTRACT FROM AUTHOR]

The effective solubilities (maximum contents) of Ta and Nb in model felsic lithium-fluoride melts of variable alkalinity and alumina content were experimentally determined at the dissolution of Ta–Nb and Nb minerals: pyrochlore, microlite, ilmenorutile, and ferrotapiolite at T = 650–850°C and P = 100 and 400 MPa. The Ta and Nb partitioning in the mineral-melt systems was also studied. When pyrochlore is dissolved in granitoid melts at P = 100 MPa and T = 650–850°C, the highest effective solubilities of Nb (0.7–1.8 wt %) are obtained in alkaline melt, and they significantly decrease (to 0.03–0.5 wt %) in subaluminous and peraluminous melts. A temperature increase increases the solubility (content) of Nb in the melt. Similar dependences were obtained for Ta solubility by dissolving microlite. In peraluminous granitoid melt, microlite remains stable, while pyrochlore becomes unstable. A pressure decrease from 400 to 100 MPa in alkaline and subaluminous melts was found out to not significantly affect on the dissolution of microlite and pyrochlore, whereas Ta and Nb contents in the peraluminous melt noticeably decrease. The dependences of Nb solubility and its partitioning between granitoid melts and ilmenorutile on the alkalinity–alumina content of the melt are similar to those for the dissolution of columbite and tantalite. The dependences obtained by dissolving ferrotapiolite, pyrochlore, and microlite differ from them. [ABSTRACT FROM AUTHOR]

The demand for pure uranium and uranium compounds of an industrial standard is tremendously increasing due to its wide array of utilities in electron microscopy, catalysis, armor-piercing, and nuclear explosions, among others. The raw ore and some of the products after alkaline leaching were characterized by X-ray fluorescence, X-ray diffraction, inductively coupled plasma mass spectroscopy, and scanning electron microscopy analyses. Dissolution kinetics and thermodynamics were examined under the experimental conditions at different sodium hydroxide concentrations, reaction temperature, and particle size towards purified uranyl leach liquor which could further be processed to industrial ammonium diuranate. The experimental results affirmed that the best parameters comprised a residence time of 120 min, reaction temperature of 75 °C, sodium hydroxide concentration of 2.5 mol/L, and particle size of 75 µm, yielding a dissolution efficiency of 96.1% with activation energy of 41.39 kJ/mol. [ABSTRACT FROM AUTHOR]

Natural silicates are promising sources of divalent cations, which are necessary for the mineralization of CO2 in the form of carbonates. The kinetics of natural talc dissolution was studied in flow-through reactors at 25°C in solutions of hydrochloric, citric, and oxalic acids at pH 3. An increase in the rate of talc dissolution in the presence of organic ligands of citrate and oxalate by about 3–4 times is characteristic of only the initial stage of mineral dissolution. The stationary rates of talc dissolution were detected ~30–40 h after the start of the experiment and were ~3E–10–16 mol/cm2 s. [ABSTRACT FROM AUTHOR]

Cyclosporine A (CP) inclusion complex using cyclodextrin (binary) and cyclodextrin with TPGS (ternary) was prepared by the freeze-drying method. The phase solubility study was performed to calculate the solubility parameters. The prepared formulations were evaluated for saturation solubility and drug release studies. The spectroscopy and molecular docking studies were performed to confirm the formation of inclusion complex. The phase solubility results revealed a high stability constant for both binary and ternary samples. A significant enhancement in saturation solubility and dissolution was found in the prepared inclusion complexes. The spectroscopy studies revealed no interaction between the drug and carrier. The molecular docking study displayed the formation of a stable complex with a good docking score. The diffraction pattern showed the conversion of crystalline CP into an amorphous form after the formation of the inclusion complex. The findings were also supported by the saturation solubility study, which showed a significant enhancement in solubility. From the results, it can be concluded that Cyclosporine A inclusion complex using HP βCD with TPGS is an excellent delivery system. Therefore, the prepared delivery systems may be an alternative to the conventional delivery system for enhanced solubility of highly lipophilic drugs. [ABSTRACT FROM AUTHOR]

Drug solubility and dissolution remain a significant challenge in pharmaceutical formulations. This study aimed to formulate and evaluate repanglinide (RPG) nanosuspension-based buccal fast-dissolving films (BDFs) for dissolution enhancement. RPG nanosuspension was prepared by the antisolvent-precipitation method using multiple hydrophilic polymers, including soluplus®, polyvinyl alcohol, polyvinyl pyrrolidine, poloxamers, and hydroxyl propyl methyl cellulose. The nanosuspension was then directly loaded into BDFs using the solvent casting technique. Twelve formulas were prepared with a particle size range of 81.6–1389 nm and PDI 0.002–1 for the different polymers. Nanosuspensions prepared with soluplus showed a favored mean particle size of 82.6 ± 3.2 nm. The particles were spherical and non-aggregating, as demonstrated by SEM imaging. FTIR showed no interaction between soluplus and RPG. Faster dissolution occurred for the nanosuspension in comparison with pure RPG (complete release vs 60% within 30 min). The nanosuspension was successfully incorporated into BDFs. The optimum film formula showed 28 s disintegration time, and 97.3% RPG released within 10 min. Ex-vivo permeation profiles revealed improved RPG nanosuspension permeation with the cumulative amount of RPG permeated is103.4% ± 10.1 and a flux of 0.00275 mg/cm2/min compared to 39.3% ± 9.57 and a flux of 0.001058 mg/cm2/min for pure RPG. RPG was successfully formulated into nanosuspension that boosted drug dissolution and permeation. The selection of the ultimate NP formula was driven by optimal particle size, distribution, and drug content. Soluplus NPs were shown to be the successful formulations, which were further incorporated into a buccal film. The film was evaluated for ex-vivo permeation, confirming successful RPG formulation with improved performance compared to pure drugs. [ABSTRACT FROM AUTHOR]

Ionic Liquids (ILs) have been used to address issues such as recyclability, cost-effectiveness, and tailored thermophysical properties. This is most relevant to recent efforts directed at dissolving cellulose for filament spinning and bioproduct development. Herein, we introduce a simple method to investigate how interactions between cellulose films (roughness, Rh = 37 nm) and ILs specifically 1-butyl-3-methylimidazolium acetate ([bmim][OAc]), 1-butyl-3-methylimidazolium chloride ([bmim][Cl]), 1-ethyl-3-methylimidazolium acetate ([emim][OAc]), and 1-ethyl-3-methylimidazolium chloride ([emim][Cl]), along with their water mixtures (0, 5, and 10 wt%) affect thermophysical properties relevant to cellulose dissolution (surface tension, γ; contact angle, θ; diffusivities, D; and bulk density, ρ) at 363.15 K and 0.1 MPa under argon and air atmospheres. Thermophysical properties relevant to cellulose dissolution were measured at 363.15 K and 0.1 MPa under argon (surface tension, γ, contact angle, θ), and air (diffusivities, D and bulk density, ρ) atmospheres to reveal the effect of the IL counter ions on the involved interactions with water. In general, water increased γ, θ, but reduced D, which supports experimental observations indicating the detrimental effect of water on IL-cellulose interactions. The [emim]+ cation (in [emim][OAc] and [emim][Cl]), produced a lower contact angle with cellulose while the interfacial properties (γ, θ, D) for ILs with the [OAc]− anion were marginally affected by water. By contrast, the two ILs carrying [Cl]− anions exhibited a significant reduction in D (from 11.7 · 10 - 13 to 2.9 · 10 - 13 m 2 s - 1 ) in the cation shift from [emim]+ to [bmim]+ at 363.15 K and 0.1 MPa, with 0% water content. Overall, we present a methodical approach rooted in experimental and theoretical approaches to facilitate our understanding of ionic liquids (ILs), especially within the domain of bioprocessing. [ABSTRACT FROM AUTHOR]

The most promising active ingredient of Crocus sativus L., crocetin (CCT), has been demonstrated to possess many biological activities. However, only a few studies have been conducted on CCT formulation, especially in oral formulation, mainly due to its insolubility in water, which limits its application for oral administration. This article reports an equilibrium saturation solubility and single-pass intestinal perfusion studies conducted to classify the biopharmaceutics classification system (BCS) of CCT. To enhance in vitro dissolution and in vivo oral bioavailability, ternary solid dispersions of CCT (CCT-SDs) with soluplus (SOL) as hydrophilic carrier and meglumine (MEG) as alkalizer were optimized using response surface methodology (RSM) with central composite design (CCD) experiments. Four different preparation methods were evaluated using the optimal formulation, including solvent evaporation, ball milling, spray drying, and freeze-drying. Prepared formulations were characterized by TG-DSC, FTIR, X-RPD, and SEM; the pharmacokinetic studies were performed in rats after oral administration. The cumulative dissolution rate of CCT-SDs containing SOL and MEG prepared by the ball milling method was 97.1% at 15 min and remained at 95.6% at 480 min, which was significantly higher than that of untreated CCT. The lower crystallinity, smaller particle size, and higher microenvironment pH (pHM) were observed in CCT-SDs prepared by the ball milling method. In vivo absorption of CCT-SDs (Cmax = 52.789 ± 12.441 μg/mL and AUC0-12 = 191.748 ± 35.043 μg/mL·h) was greater than untreated CCT (Cmax = 5.918 ± 1.388 μg/mL and AUC0-12 = 44.309 ± 7.264 μg/mL·h). In conclusion, the current study provides ternary solid dispersion formulation of CCT to increase the in vitro dissolution and in vivo bioavailability, which will benefit the commercial production and future clinical applications of CCT. [ABSTRACT FROM AUTHOR]

Sol–gel synthesis parameters can significantly influence bioactive glass's structure, dissolution rates, and biocompatibility. For this study, various drying times and calcining temperatures were explored for a Zinc (Zn2+), Copper (Cu2+), and Cobalt (Co2+) doped silicate-based sol–gel bioactive glass composition. Surface area measurements showed an increase in the particle's surface area with decreased calcining temperature, whereas the particle size decreased with longer drying time and higher calcining temperature. The micropore area and volume showed an inverse relationship to the reduced particle size, with the microporosity increasing as the drying time was extended with the calcining temperature below the glasses' transition temperature (560–586 °C). A Kilchoanite (Ca3(Si2O7)) crystalline phase was present in each sample, and with increased calcining temperature above the Tg of the glasses, the degree of crystallinity increased. A drying time of 72 hrs with a calcining temperature of 450 °C showed an enhanced surface area (120 m2/g) with smaller average particle size (0.43 µm), increased microporosity, ion release rates within toxicity and pH limits, and growth inhibition for both gram-positive (S. aureus) and gram-negative (E. coli) bacteria. Highlights: A drying time of 72 hrs leads to smaller particle size and increased microporosity below the Tg. A calcining temperature of 450 °C increases surface area and decreases crystallinity. Zinc, copper, and cobalt ion releases were within the limits of cytotoxicity and pH. A drying time of 72 hrs and calcining temperature of 450 °C presented bacterial growth inhibition. [ABSTRACT FROM AUTHOR]

The corrosion behavior of the aluminum-alloyed austenitic steels Fe-18Ni-12Cr-2.9Al and Fe-18Ni-12Cr-2.3Al-Nb-C was investigated at 700 °C in static Pb for 1000 h as a function of the concentration of dissolved oxygen in the liquid metal. In Pb with ~ 5 × 10–9 mass % dissolved oxygen, both steels showed dissolution. Depth of corrosion averaged 67 (± 18) µm and 78 (± 25) µm for Fe-18Ni-12Cr-2.3Al-Nb-C and Fe-18Ni-12Cr-2.9Al, respectively. In Pb with higher oxidation potential of 2 × 10–6 mass %O, both steels showed protective and accelerated oxidation. The protective thin oxide film (≤ 1 µm) was composed of outermost Fe-rich, intermediate Cr-rich and inner Al-rich sublayers. The thicker oxide scale was of irregular thickness (2 ÷ 30 µm) and consisted of Fe–Cr mixed oxide with Ni-rich metallic inclusions. [ABSTRACT FROM AUTHOR]

Calcium sulfoaluminate-belite (CSAB) cement is considered a viable and environmentally friendly alternative to Portland cement. Ye'elimite or calcium sulfoaluminate which is the primary phase of CSAB cement undergoes rapid hydration, leading to the formation of ettringite or monosulfate as the major hydration product. The reactivity of ye'elimite can be influenced by other phases (e.g., calcium sulfate, calcium hydroxide, and alkalis) present in CSAB cement, affecting the evolution of hydrated phase assemblage. CSAB cements are known for their useful attributes such as quick setting, early-stage strength development, and the ability to compensate for shrinkage. These properties are directly linked to the early-age hydration of CSAB cement. This study is focused on the influence of alkali and calcium sulfate on the hydration of ye'elimite. Early-age hydration (up to 3 days) of laboratory-synthesized ye'elimite was studied under different alkali concentrations in the mix with or without calcium sulfate. The addition of gypsum was found to accelerate the early-age hydration of ye'elimite, and the alkalis contributed to further acceleration of the hydration in the initial hours. Alkalis were found to stabilize the hydration beyond a few hours, leading to a lower degree of hydration. Furthermore, alkalis influenced the formation as well as morphology of the hydration products, and the influence was more predominant in the absence of gypsum. [ABSTRACT FROM AUTHOR]

The use of in vitro-in vivo correlation (IVIVC) for extended release oral dosage forms is an important technique that can avoid potential clinical studies. IVIVC has been a topic of discussion over the past two decades since the inception of USFDA guidance. It has been routinely used for biowaivers, establishment of dissolution safe space and clinically relevant dissolution specifications, for supporting site transfers, scale-up and post approval changes. Although conventional or mathematical IVIVC is routinely used, other approach such as mechanistic IVIVC can be of attractive choice as it integrates all the physiological aspects. In the present study, we have performed comparative evaluation of mechanistic and conventional IVIVC for establishment of dissolution safe space using divalproex sodium and tofacitinib extended release formulations as case examples. Conventional IVIVC was established using Phoenix and mechanistic IVIVC was set up using Gastroplus physiologically based biopharmaceutics model (PBBM). Virtual dissolution profiles with varying release rates were constructed around target dissolution profile using Weibull function. After internal and external validation, the virtual dissolution profiles were integrated into mechanistic and conventional IVIVC and safe space was established by absolute error and T/R ratio's methods. The results suggest that mechanistic IVIVC yielded wider safe space as compared to conventional IVIVC. The results suggest that a mechanistic approach of establishing IVIVC may be a flexible approach as it integrates physiological aspects. These findings suggest that mechanistic IVIVC has wider potential as compared to conventional IVIVC to gain wider dissolution safe space and thus can avoid potential clinical studies. [ABSTRACT FROM AUTHOR]

Mechanistic modeling of in vitro experiments using metabolic enzyme systems enables the extrapolation of metabolic clearance for in vitro-in vivo predictions. This is particularly important for successful clearance predictions using physiologically based pharmacokinetic (PBPK) modeling. The concept of mechanistic modeling can also be extended to biopharmaceutics, where in vitro data is used to predict the in vivo pharmacokinetic profile of the drug. This approach further allows for the identification of parameters that are critical for oral drug absorption in vivo. However, the routine use of this analysis approach has been hindered by the lack of an integrated analysis workflow. The objective of this tutorial is to (1) review processes and parameters contributing to oral drug absorption in increasing levels of complexity, (2) outline a general physiologically based biopharmaceutic modeling workflow for weak acids, and (3) illustrate the outlined concepts via an ibuprofen (i.e., a weak, poorly soluble acid) case example in order to provide practical guidance on how to integrate biopharmaceutic and physiological data to better understand oral drug absorption. In the future, we plan to explore the usefulness of this tutorial/roadmap to inform the development of PBPK models for BCS 2 weak bases, by expanding the stepwise modeling approach to accommodate more intricate scenarios, including the presence of diprotic basic compounds and acidifying agents within the formulation. [ABSTRACT FROM AUTHOR]

Speciation analysis plays a key role in understanding the biological activity and toxicity of an element. So far, classical speciation analysis focused only on the dissolved fraction of an elemental species, whereas nanoparticle forms of analytes are being widely found in consumer and industrial products. A significant contributor to human exposure to nanoparticles is through food into which nanoparticles can be incorporated from endogenous sources or they may be formed naturally in the living organisms. Nanoparticles often undergo changes in the food matrices and upon consumption, in the gastrointestinal tract, which present a significant challenge to their characterisation. Therefore, a combination of both classical and nanoparticle speciation analytical techniques is needed for the characterisation of both dissolved and particulate forms of the chemical species. This article presents and discusses the current trends in analysis of nanoparticle behaviour in the gastrointestinal tract and formation and characterisation of biogenic nanoparticles. [ABSTRACT FROM AUTHOR]

Background: Phosphate buffer is often used as a replacement for the physiological bicarbonate buffer in pharmaceutical dissolution testing, although there are some discrepancies in their properties making it complicated to extrapolate dissolution results in phosphate to the in vivo situation. This study aims to characterize these discrepancies regarding solubility and dissolution behavior of ionizable compounds. Methods: The dissolution of an ibuprofen powder with a known particle size distribution was simulated in silico and verified experimentally in vitro at two different doses and in two different buffers (5 mM pH 6.8 bicarbonate and phosphate). Results: The results showed that there is a solubility vs. dissolution mismatch in the two buffers. This was accurately predicted by the in-house simulations based on the reversible non-equilibrium (RNE) and the Mooney models. Conclusions: The results can be explained by the existence of a relatively large gap between the initial surface pH of the drug and the bulk pH at saturation in bicarbonate but not in phosphate, which is caused by not all the interfacial reactions reaching equilibrium in bicarbonate prior to bulk saturation. This means that slurry pH measurements, while providing surface pH estimates for buffers like phosphate, are poor indicators of surface pH in the intestinal bicarbonate buffer. In addition, it showcases the importance of accounting for the H2CO3-CO2 interconversion kinetics to achieve good predictions of intestinal drug dissolution. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to clarify the extent to which the dissolution profiles of immediate release (IR) products of various drugs differ between biorelevant bicarbonate buffer (BCB) and compendial phosphate buffer (PPB). Methods: The dissolution profiles of the IR products of fifteen poorly soluble ionizable drugs were measured in BCB and PPB. BCB was set to be relevant to the small intestine (pH 6.8, 10 mM). The pH was maintained using the floating lid method. The Japanese pharmacopeia second fluid (JP2, 25 mM phosphate buffer, nominal pH 6.8) was used as compendial PPB. The compendial paddle apparatus was used for the dissolution tests (500 mL, 50 rpm, 37°C). Results: In 11/15 cases, a difference in dissolved% (< 0.8 or > 1.25-fold) was observed at a time point. In 4/15 cases, the ratio of the area under the dissolution curve was not equivalent (< 0.8 or > 1.25-fold). In the cases of free-form drugs, the dissolution rate tended to be slower in BCB than in JP2. In the case of salt-form drugs, a marked difference was observed for the cases that showed supersaturation. However, no trend was observed in the differences. Conclusions: Many IR products showed differences in the dissolution profiles between biorelevant BCB and compendial PPB. With the floating lid method, BCB is as simple and easy to use as PPB. Biorelevant BCB is recommended for dissolution testing. [ABSTRACT FROM AUTHOR]

To investigate the dissolution behaviors of Al2O3 inclusions in CaO–5wt%MgO–SiO2–30wt%Al2O3–TiO2 system ladle slags, confocal scanning laser microscopy was conducted on the slags with different TiO2 contents (0–10wt%), and scanning electron microscopy was performed to study the interfacial reaction between Al2O3 and this slag system. The results disclose that the dissolution of Al2O3 inclusions does not result in the formation of new phases at the boundary between the slag and the inclusions. In TiO2-bearing and TiO2-free ladle slags, there is no difference in the dissolution mechanism of Al2O3 inclusions at steelmaking temperatures. Boundary layer diffusion is found as the controlling step of the dissolution of Al2O3, and the diffusion coefficient is in the range of 4.18 × 10−10 to 2.18 × 10−9 m2/s at 1450–1500°C. Compared with the solubility of Al2O3 in the slags, slag viscosity and temperature play a more profound role in the dissolution of Al2O3 inclusions. A lower viscosity and a lower melting point of the slags are beneficial for the dissolution. Suitable addition of TiO2 (e.g., 5wt%) in ladle slags can enhance the dissolution of Al2O3 inclusions because of the low viscosity and melting point of the slags, while excessive addition of TiO2 (e.g., 10wt%) shows the opposite trend. [ABSTRACT FROM AUTHOR]

The development of fertilizer technology is directed towards the production and application of slow or controlled fertilizers. In order to prevent these losses and difficulties, slow and controlled release fertilizers can be produced. Slow or controlled release fertilizers are fertilizers that can be in organic or inorganic form, in solid or liquid form, release the nutrients they contain more slowly than conventional fertilizers, depending on water dissolution, microbial decomposition, growing environment conditions, and thus provide a longer lasting effect. Thus, it is possible to provide the plant with the necessary plant nutrients during the growth period. In this study, three different elements were bound to sugar beet pulp modified with citric acid and their dissolution tendencies were investigated in different environments from the material to which the elements were attached. The dissolution trends were chosen to reflect the natural medium as best as possible. The best dissolution tendencies for all 3 elements were realized in percolations made with EDTA solutions. After the EDTA solution, the dissolution tendencies obtained in the study are followed by citric acid solution, humic acid solution, buffer solution, tap water, and pure water, respectively. The media that best represent the soil solution are tap water, humic acid, and citric acid solutions. Therefore, these two environments are of great importance for the study. It was determined that the modified sugar beet pulp binds these metal ions at the rate of 108.2, 87.1, and 45.7 mg/g, respectively, by contacting with Cu2+, Zn2+, and Mn2+ solutions for 24 h. The dissolution tendencies of this metal-bound bonded material in different environments were investigated. After the EDTA solution, the dissolution tendencies obtained in the study are followed by citric acid solution, humic acid solution, buffer solution, tap water, and pure water, respectively. The media that best represent the soil solution are tap water, humic acid, and citric acid solutions. Therefore, these two environments are of great importance for the study. In the light of these results, it has been shown that modified sugar beet pulp with copper, zinc, and manganese binding can be used effectively as a slow dissolving micronutrient fertilizer in soils with trace element deficiency. [ABSTRACT FROM AUTHOR]

The dissolution kinetics of metakaolin are examined at room temperature in NaOH solutions at concentrations of (0.1, 5, or 10) mol L−1 and at liquid-to-solid mass ratios (L/S) of 50 or 1000. Both the dissolved Si and Al concentrations as well as the morphology and structure of the solid are reported at various times. The dissolution rate is approximately constant for about an hour, (0.0043–0.1030) µmol m−2 s−1, depending on alkalinity and L/S. Some precipitates are observed within the first ten minutes but do not affect the dissolution rate during that first hour, implying that the precipitates form in the solution and do not block or alter the metakaolin surfaces significantly. The dissolution rate during the first 45 min increases with alkalinity and decreases with L/S. The metakaolin exfoliates at higher NaOH concentrations, exposing more surface area to the solution. The effect of exfoliation increases the apparent dissolution rate and promotes more congruent dissolution. These observations not only improve our understanding of the metakaolin dissolution mechanisms but also provide insights into the reactivity of calcined clays that are becoming increasingly important to the sustainability of the cement and concrete industry. [ABSTRACT FROM AUTHOR]

The main goal of this study was to recover the cadmium and nickel content of waste zinc filter cake. In this regard, at first, the dissolution of these elements in sulfuric acid and optimization of the solution process were considered. Effects of various parameters such as dissolution reaction time (10–40 min), temperature (25–80°C), sulfuric acid concentration (2–11 vol.%), and particle size distribution (four size fractions) under liquid/solid ratio of 10 and stirring speed of 600 rpm on leaching of Cd dissolution from Cd–Ni filter cake were evaluated and optimized by Taguchi method. The experimental plan was designed using an orthogonal array, L16 (44), which denotes four parameters with four levels. The optimum dissolution conditions proposed by the Design Expert software were a reaction time of 40 min, temperature of 80 °C, sulfuric acid concentration of 8 vol.%, and particle size distribution of −75 + 53 µm with predicted dissolution content of Cd equals to 93.15% by the software. In the optimum condition, 95.2% of the Cd content was leached during the verifying test. According to the results, reaction time, particle size distribution, acid concentration, and temperature are the most affecting parameters on Cd dissolution, respectively. Separation of Ni and Cd present in the solution after dissolution using sodium sulfate precipitation in the pH range of 1–5 was studied at the second stage, and the results show that at pH = 3, maximum separation of Ni and Cd (with weight ratio of Cd to Ni in the precipitates equals to 46.2) was achieved. [ABSTRACT FROM AUTHOR]

Natural Mg phyllosilicates are potential sources of divalent cations, which are necessary for the mineralization of CO2 into carbonates. The influence of inorganic () and organic (oxalate and citrate) ligands on the dissolution kinetics of talc and serpentine was studied in experiments in a flow-through reactor at 25°C. The dissolution rates of natural silicates r (mol cm–2 s–1) in solutions of various composition were calculated at the stationary stage of dissolution after a rapid initial stage, which is characterized by the formation of a surface leached layer depleted in magnesium. The presence of ligands increases the dissolution rate of magnesium silicates due to the formation of surface complexes, which leads to magnesium separation from the surface and transfer into solution. The initial incongruent stage may be the most promising for the development of carbonation technologies, because the minimum removal of the network-forming elements prevents the undesirable formation of secondary minerals (for example, clays), which exclude divalent cations from the carbonation process and greatly reduce the permeability of rocks. [ABSTRACT FROM AUTHOR]

Electric arc furnace slag (EAF) and sandstone waste (SW) are two of the most abundantly generated industrial wastes whose utilization as precursors and supplementary cementitious materials has not been exhaustively studied. The current research study comprehensively investigates the effects of incorporating varying proportions (0–90%) of re-melted EAF as a co-additive on the engineering properties of elevated (80 °C) and ambient (30 °C) cured alkali-activated SW-based binders. Extensive laboratory tests were conducted to assess the physio-mechanical and durability performance of the resulting alkali-activated materials (AAM). Detailed mineralogical and microstructural characterization of SW, EAF, and alkali-activated samples was carried out using sophisticated analytical techniques. Results advocated that irrespective of the curing temperatures, SW-based AAM showed improved setting behavior, compressive strength, water absorption, and porosity characteristics with the increment of EAF at all substitution levels due to the concomitant development of CASH-CSH-NASH gel phases. Overall, it can be inferred that EAFs as a pozzolanic material successfully augmented the properties of SW-based alkali-activated binders, providing an efficient solution for disposal and negative environmental impacts associated with industrial wastes. [ABSTRACT FROM AUTHOR]

Lattice Boltzmann (LB) methods with reactive boundary conditions are widely used in pore-scale simulations of dissolution and ablation processes. The staircase approximation of curved boundary is often employed because of its simplicity in handling solid structure changes. In this work, the mass transfer of two typical LB reactive boundary schemes are analyzed for the staircase boundary. The Type I boundary scheme is based on relations of local distribution functions and a wet-node boundary mesh. The Type II boundary scheme adopts the half-way bounce-back scheme. Boundary concentrations are determined by finite difference, and a link-wise boundary mesh is used. The analyses demonstrate that for straight boundaries, both the boundary schemes have accurate mass transfer rates, which means the mass transfer calculated by exchanges of distribution functions is the same as that calculated by reaction rates. For curved boundaries with staircase approximation, including interfacial normal directions in the Type I boundary scheme can provide accurate mass transfer for inclined straight boundaries. However, if the staircase boundary geometry is used directly without normal directions, the reaction rate will be overestimated. One-dimensional and two-dimensional reaction-diffusion processes with dissolution are simulated to validate the analyses. Both the boundary schemes work well for one-dimensional simulations. For two-dimensional simulations, the Type II boundary scheme significantly overestimates the reaction rate, and stronger artificial anisotropic effects are observed. The Type I boundary scheme with normal directions has better performance, but error still exists. [ABSTRACT FROM AUTHOR]

Purpose: Tegafur (TF) is one of the most important clinical antitumor drugs with poor water solubility, severely reducing its bioavailability. This work develops new cocrystals to improve the solubility of TF and systematically investigates the intermolecular interactions to provide new insights into the formation of cocrystal and changes in physicochemical properties. Method: In this paper, two new 1:1 cocrystals of TF with 2,4 dihydroxybenzoic acid (2,4HBA) and p-nitrophenol (PNP) were synthesized. The cocrystal products were identified and characterized by various solid state analysis techniques. And the high performance liquid chromatography (HPLC) was conducted to determine the solubility and dissolution rate of TF and cocrystals. Moreover, the quantum chemistry calculations of crystal structure provided theoretical support for the results. Result: Compared with pure TF, the solubility and dissolution rate of TF-2,4HBA is significantly increased in a pH 6.8 buffer at 37°C. Under accelerated storage conditions (40°C, 75% RH), all cocrystal exhibits excellent stability over 8 weeks. Hirshfeld surface (HS) analysis, atoms in molecules (AIM) analysis, interaction region indicator (IRI) analysis, molecular electrostatic potential surface (MEPS) analysis and frontier molecular orbital (HOMO–LUMO) analysis were integrated to understand the hydrogen bonding interaction more comprehensively. The simulation results are in good agreement with the experimental data. The results show that the analysis of physical and chemical properties of TF-PNP cocrystal and TF crystal by quantum chemistry method is reliable at molecular level. Conclusion: These results are helpful to provide guiding methods in the cocrystal development and theoretical study of tegafur. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to develop a Temporal Biopharmaceutic Classification System (T-BCS), linking Finite Dissolution Time (F.D.T.) and Mean Dissolution Time (M.D.T.) for Class I/III drugs and Mean Dissolution Time for saturation (M.D.T.s.) for Class II/IV drugs. Methods: These parameters are estimated graphically or by fitting dissolution models to experimental data and coupled with the dose-to-solubility ratio (q) for each drug normalized in terms of the actual volume of dissolution medium (900 mL). Results: Class I/III drugs consistently exhibited q values less than 1, aligning with expectations based on their solubility, while some Class II/IV drugs presented a deviation from anticipated q values, with observations of q < 1. This irregularity was rendered to the dissolution volume of 250 mL used for biopharmaceutical classification purposes instead of 900 mL applied as well as the dual classification of some sparingly soluble drugs. Biowaivers were also analyzed in terms of M.D.T., F.D.T. estimates and the regulatory dissolution time limits for rapidly and very-rapidly dissolved drugs. Conclusions: The T-BCS is useful for establishing correlations and assessing the magnitude of M.D.T., F.D.T., or M.D.T.s. for inter- and intra-class comparisons of different drugs and provide relationships between these parameters across all the models that were utilized. [ABSTRACT FROM AUTHOR]

In the Algerian-Tunisian border region lies the Tebessa plain, which belongs to the Saharan Atlas domain and is characterized by a semi-arid climate and high salinity, often rendering the groundwater unusable. The objective of this research is to highlight groundwater salinization using statistical and geostatistical methods to model this spatial heterogeneity. A total of 30 data points were used, and the statistical analysis revealed a strong association between chlorides, sulfates, electrical conductivity, and values significantly exceeding the standards. Surface and directional variograms for EC (electrical conductivity), SO4 (sulfates), and Cl (chlorides) exhibit anisotropy, with the major axis showing a hole effect and a periodicity of 5 km. Geostatistical mapping through ordinary kriging allowed us to identify areas of high salinity and deduce the underlying cause; which is the dissolution of gypsiferous formations. These results were confirmed by thermodynamics and Sr2+/Ca2+ ratio. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass is available in abundance as a renewable resource, but the major portion of it is often discarded as waste without utilizing its immense potential as an alternative renewable energy resource. To overcome recalcitrance of lignocellulosic biomass, various pretreatment methods are applied to it, so that the complex and rigid polymeric structure can be broken down into fractions susceptible for enzymatic hydrolysis. Effective and efficient biomass processing is the goal of pretreatment methods, but none of the explored pretreatment methods are versatile enough to fulfil the requirement of biomass processing with greater flexibility in terms of operational cost and desired output efficiency. Deployment of green solvents such as ionic liquids for the pretreatment of lignocellulosic biomass has been a topic of discussion amongst the scientific community in recent times. The presented work provides a detailed overview on the deployment of ionic liquid for the pretreatment of lignocellulosic biomass coupled with a brief discussion on other pretreatments methods. The recyclability and reusability along with other unique properties makes an ionic liquid pretreatment different from the other traditional pretreatment methods. Also, this study explores diverse critical parameters that governs the dissolution process of biomass. Hazardous properties of ionic liquids have also been explored. Future perspective and recommendations have been given for an efficient, effective, and eco-friendly deployment of ionic liquid in biomass pretreatment process. [ABSTRACT FROM AUTHOR]

Objective: This study aims to establish a Flow-through Visualization Dissolution System (FVDS) that combines time-lapse macro-imaging and a flow-through cell to simultaneously elucidate dissolution and disintegration profiles. Methods: Three cefaclor extended-release tablets (CEC-1, CEC-2, CEC-3) from different manufacturers were subjected to dissolution tests using both the US Pharmacopeia basket method and the FVDS method. Two dissolution media plans were implemented in FVDS: i) Plan I involved dissolution in pH1.0 medium for 12 h; ii) Plan II initiated dissolution in pH1.0 medium for 1 h, followed by pH6.8 phosphate buffer for 11 h. The resulting dissolution data were fitted using classic mathematical models. Pixel information was further extracted from images obtained using FVDS and plotted over time. Results: The basket method showed the cumulative dissolution of all three tablets in pH1.0, pH4.0 and water reached 80% within 6 h, but remained below 60% in the pH6.8 medium. The f2 values indicated CEC-2 was similar to CEC-1 in the pH4.0 medium, pH6.8 medium and water. Using FVDS with medium plan II, the cumulative dissolution of CEC-1 and CEC-2 reached about 80% showing similarity, while no similarity was observed between CEC-3 and CEC-1. The f2 factor of the percentage area change profiles also showed consistent results in the dissolution profile of medium plan II. However, FVDS with medium plan I cannot distinguish between CEC-2 and CEC-3. Conclusion: FVDS offers an alternative to traditional dissolution methods by integrating imaging analysis as a complementary tool to disintegration and dissolution testing methods. [ABSTRACT FROM AUTHOR]

For improving the wear resistance of soft Al substrate by fabricating surface composite, commercial Al metal matrix composite (MMC) SiCp/A356 sheet was cladded onto 1060 Al substrate by friction stir brazing (FSB) process, in which a pinless tool and Zn solder were used to avoid pin wear and to extend bonded width. The MMC/Al (top/bottom) configuration exhibited intimately contacted interface, Al-Zn bond seam reinforced by SiC particles and higher shear strength (70 MPa) due to sufficient dissolution with the aid of torquing action directly on the MMC sheet from the large rotating shoulder. For Al/MMC configuration, excessive softening of the top 1060 Al and indirect micro-shearing on the bottom SiCp/A356 resulted in excessive expulsion of molten Zn, insufficient dissolution, poor wettability and lower shear strength (35 MPa). FSB was able to produce a surface composite layer with large width up to shoulder diameter in air. [ABSTRACT FROM AUTHOR]

Celecoxib (CXB) is a nonsteroidal anti-inflammatory drug (NSAID). However, the application of CXB has been compromised by its poor aqueous solubility and low oral bioavailability. We developed a series of ternary solid dispersions (SDs) of CXB to increase its solubility. In this study, the polymers were screened to determine that they have the potential to increase the solubility of CXB in the solution. A hydrophilic polymer-hydroxypropyl methylcellulose (HPMC) and a surfactant Tween80 were employed as matrix respectively in the optimized formulations. Experimental data revealed that CXB was molecularly distributed within all dispersions in amorphous form by using Differential Scanning Calorimetry (DSC), Polarizing Light Microscopy (PLM), and X-ray powder diffraction (XRD). Fourier Transform Infrared Spectroscopy (FTIR) results showed that the characteristic peaks of CXB have shifted. Compared with pure CXB, the addition of excipients can reduce the contact angle, and improve the solubility of CXB. Ternary SDs were dissolved in PBS (pH 6.8) and formed drug-carrying nanoparticles. In vitro dissolution results indicated that the dissolution amount of HPMC-CXB 5 : 1 SD (32.08±1.56% for 120 min) was higher than pure CXB (3.09±0.29%). In particular, the greatest dissolution enhancement was obtained from the test of which the result was HPMC/Tween80-CXB 3 : 2 : 1 SD (44.12±2.01% for 120 min). This study showed that ternary SDs could be a promising strategy for improving CXB dissolution. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the present study was to investigate the effect of food viscosity on the dissolution rate of a drug. There are two types of viscosity, macroviscosity and microviscosity. Macroviscosity affects the diffusion layer thickness, whereas microviscosity affects the molecular diffusion coefficient. The mass transfer coefficient (kc) in the intrinsic dissolution rate (IDR) depends on the viscosity (η) as kc ∝ ηa (a is an exponent on η). In theory, for rotating flow over a disk, if a thickener increases only macroviscosity, a = -1/6, and if it increases both macroviscosity and microviscosity equally, a = -7/6. Method: Benzocaine was used as a model drug. Hydroxypropyl cellulose (HPC) and methylcellulose (MC) were employed as control thickeners that increase only macroviscosity. Sucrose was employed as a control thickener for both macroviscosity and microviscosity. The FDA breakfast homogenate (BFH) was diluted with distilled water or 1 mM HCl with/without pepsin digestion. The IDR value was measured by the paddle-over-disk method. Results: The η value of 30% BFH distilled water was 209 mPa∙s, about 300 times higher than distilled water. It was further increased by HCl (430 mPa∙s), and reduced by pepsin digestion (35 mPa∙s). The kc value was little affected by BFH (a = 0.00 to -0.09), slightly less than those in HPC (a = -0.19) and MC (a = -0.21). Sucrose decreased the kc value more significantly (a = -0.70). Conclusion: The IDR and kc values of benzocaine were little affected by BFH, suggesting that BFH increased only macroviscosity. [ABSTRACT FROM AUTHOR]

Celecoxib, the first cyclooxygenase-2 selective nonsteroidal anti-inflammatory drug, has a wide range of pharmacological effects, including anti-inflammatory, antirheumatic and antitumor effects. However, celecoxib's poor solubility severely limits its clinical application. Thus, a novel ternary solid dispersion system was developed using PVP K30 and hydroxypropyl-β-cyclodextrin (HPβCD) as carrier materials in order to improve its solubility and dissolution behavior. The solid dispersion system was characterized by SEM, XRD, FT-IR, DSC, in vitro dissolution, saturated solubility, and contact angle test; the stability of the samples under extreme environments was investigated as well. The results showed that the novel ternary solid dispersion doped with PVP K30 and HPβCD has enhanced solubility around 6.28-fold, an almost 13.94-fold increase in the dissolution rate (120 min) compared with celecoxib's active pharmaceutical ingredient. The substantial improvement in its dissolution performance is attributed to the fact that celecoxib is dispersed in the carrier material in an amorphous form and has hydrogen bonding interactions with the carrier materials. In addition, the improvement of wettability is one of the reasons for its increased solubility. In conclusion, the combination of PVP K30 and HPβCD can significantly improve the solubility of celecoxib and this novel solid dispersion system provides new ideas and methods to further improve the solubility of insoluble drugs. [ABSTRACT FROM AUTHOR]

Objectives: The study aimed to evaluate the potential for the dissolution of organic tissue in areas of simulated complexity and cleaning of root canal walls of the new iVac® endodontic irrigation system. Material and methods: Thirty mandibular premolars were evaluated by scanning electron microscopy before and after biomechanical preparation. Then, they were distributed according to the final irrigation protocol into groups with conventional irrigation, ultrasonic agitation with metallic insert (UA), and iVac® system, and new photomicrographs were obtained. For tissue dissolution analysis, glass capillaries filled with catgut were attached to the cervical and apical thirds of twenty-one prototyped upper incisors. They were weighed before and after the previously mentioned irrigation protocols. The data were statistically compared with a significance level of 5%. Results: The final irrigation provided greater cleaning of the root canal walls in the cervical, middle, and apical thirds of the root canals (P < 0.05), with no statistically significant difference between UA and iVac®, regardless of the analyzed thirds. Both ultrasonic irrigation protocols dissolved a significantly greater volume than the conventional irrigation protocol (P < 0.05), with no difference between the two protocols (P < 0.05). Conclusions: The iVac® system showed root canal wall cleaning and tissue dissolution similar to UA with a metallic insert, and both were superior to conventional irrigation. Clinical relevance: The new irrigation system iVac is more effective than conventional irrigation and has similar root canal wall cleaning and tissue dissolution to UA. [ABSTRACT FROM AUTHOR]

The aim of this paper was to investigate the effects of formulation parameters on the physicochemical and pharmacokinetic (PK) behavior of amorphous printlets of lopinavir (LPV) manufactured by selective laser sintering 3D printing method (SLS). The formulation variables investigated were disintegrants (magnesium aluminum silicate at 5–10%, microcrystalline cellulose at 10–20%) and the polymer (Kollicoat® IR at 42–57%), while keeping printing parameters constant. Differential scanning calorimetry, X-ray powder diffraction, and Fourier-transform infrared analysis confirmed the transformation of the crystalline drug into an amorphous form. A direct correlation was found between the disintegrant concentration and dissolution. The dissolved drug ranged from 71.1 ± 5.7% to 99.3 ± 2.7% within 120 min. A comparative PK study in rabbits showed significant differences in the rate and extent of absorption between printlets and compressed tablets. The values for Tmax, Cmax, and AUC were 4 times faster, and 2.5 and 1.7 times higher in the printlets compared to the compressed tablets, respectively. In conclusion, the SLS printing method can be used to create an amorphous delivery system through a single continuous process. [ABSTRACT FROM AUTHOR]

The preparation of solid dispersions by mixing insoluble drugs with polymers is the main way to improve the aqueous solubility of drugs. The introduction of organic small molecule excipients into binary solid dispersions is expected to further enhance drug solubility by regulating intermolecular hydrogen bonding within the system at the microscopic level. In this study, we used carbamazepine (CBZ) as the target drug and polyvinylpyrrolidone as the solid dispersion matrix and screened the third component from 13 organic small molecules with good miscibility in the solid dispersion based on the principle of similarity of solubility parameters. The hydrogen bonding parameters and dissociation Gibbs free energy of the 13 organic small molecule-CBZ dimer were calculated by quantum mechanical simulation, and the tryptophan (Try) was identified as the optimal third component of organic small molecule. The migration of CBZ in binary and ternary systems was also analyzed by molecular dynamics simulation. On this theoretical basis, the corresponding solid dispersions were prepared, characterized, and tested for solubility analysis, which verified that the drug solubility was stronger for the system with the addition of polar fractions and the Try was indeed the best third component of organic small molecule compound, which was consistent with the simulation predictions. This screening method may provide theoretical guidance for drug modification design and clinical studies. [ABSTRACT FROM AUTHOR]

Dissolution profiles comparison is an important element in order to support biowaivers, scale-up and post approval changes and site transfers. Highly variable dissolution can possess significant challenges for comparison and f2 bootstrap approach can be utilized in such cases. However, availability of different types of f2 and confidence intervals (CI) methods indicates necessity to understand each type of calculation thoroughly. Among all approaches, bias corrected and accelerated (BCa) can be an attractive choice as it corrects the bias and skewness of the distribution. In this manuscript, we have performed comparison of highly variable dissolution data using various software's by adopting percentile and BCa CI approaches. Diverse data with different variability's, number of samples and bootstraps were evaluated with JMP, DDSolver, R-software, SAS and PhEq. While all software's yielded similar observed f2 values, differences in lower percentile CI was observed. BCa with R-software and JMP provided superior lower percentile as compared to other computations. Expected f2 recommended by EMA has resulted as stringent criteria as compared to estimated f2. No impact of number of bootstraps on similarity analysis was observed whereas number of samples increased chance of acceptance. Variability has impacted similarity outcome with estimated f2 but chance of acceptance enhanced with BCa approach. Further, freely available R-software can be of attractive choice due to computation of various types of f2, percentile and BCa intervals. Overall, this work can enable regulatory submissions to enhance probability of similarity through appropriate selection of number of samples, technique based on variability of dissolution data. [ABSTRACT FROM AUTHOR]

Purpose: To synthesize and characterize new cocrystals of berberine chloride (BCl) for potential pharmaceutical tablet formulation. Methods: Solutions of BCl with each of three selected cocrystal formers, catechol (CAT), resorcinol (RES), and hydroquinone (HYQ) were slowly evaporated at room temperature to obtain crystals. Crystal structures were solved using single crystal X-ray diffraction. Bulk powders were characterized by powder X-ray diffraction, thermogravimetric-differential scanning calorimetry, FTIR, dynamic moisture sorption, and dissolution (both intrinsic and powder). Results: Single crystal structures confirmed the formation of cocrystals with all three coformers, which revealed various intermolecular interactions that stabilized crystal lattices, including O–H···Cl− hydrogen bonds. All three cocrystals exhibited better stability against high humidity (up to 95% relative humidity) at 25 ℃ and higher intrinsic and powder dissolution rates than BCl. Conclusion: The enhanced pharmaceutical properties of all three cocrystals, as compared to BCl, further contribute to the existing evidence that confirms the beneficial role of cocrystallization in facilitating drug development. These new cocrystals expand the structure landscape of BCl solid forms, which is important for future analysis to establish a reliable relationship between crystal structure and pharmaceutical properties. [ABSTRACT FROM AUTHOR]