Dissolution Kinetics Research Articles

Aristolochic Acid Exposure via Dermal Contact or Inhalation of Herbal Powders: Evidence of Occupational Exposure in Herbalists with Urothelial Cancer.

Emerging evidence showing urothelial cancer in herbalists is linked to aristolochic acid (AA) exposure; however, the exposure pathway remains unclear. Here, we show that dermal contact and inhalation of fine powders of AA-containing herbs are significant occupational AA exposure pathways for herbalists. We initiated the study by quantifying the amount of AA in the AA-containing powder deposited on gloves and face masks worn by the operators of an AA-containing herb grinding machine. Then, we measured the kinetics of dermal absorption and dissolution of AA from fine powders of AA-containing herbs into artificial sweat and surrogate lung fluid. Lastly, we quantified the mutagenic AA-DNA adduct levels formed in the kidneys of mice exposed to AA-containing fine powders through dermal contact. Our findings highlight an urgent occupational risk that should demand implementation of safety standards for herbalists exposed to AA-containing fine powders.

Dissolution kinetics and thermodynamics of uranium from a boltwoodite ore for nuclear fuel cycle application

Dissolution kinetics and thermodynamics of uranium from a boltwoodite ore for nuclear fuel cycle application

Chemical Aspect of Ocean Liming for CO2 Removal: Dissolution Kinetics of Calcium Hydroxide in Seawater

Chemical Aspect of Ocean Liming for CO₂ Removal: Dissolution Kinetics of Calcium Hydroxide in Seawater

ИЗУЧЕНИЕ ПРОЦЕССОВ КОМПЛЕКСООБРАЗОВАНИЯ В ПОЛИМЕРНЫХ БИОДЕГРАДИРУЕМЫХ КОМПОЗИЦИЯХ

One of the possible directions of the development of targeted substance delivery systems is the creation and introduction of biodegradable polymers into production. Their distinctive feature is that they are capable of spontaneously gradually degradation in the body due to natural biochemical processes. There is an increasing spread pharmaceutical form, which use similar excipients in their technology – medicinal ocular insert. Modified cellulose, gums and rare-cross-linked acrylic polymers are used to create a biodegradable matrix base. In terms of development approach, ocular inserts can be divided into two groups according to the principle of matrix biodegradation. In non-biodegradable composites, the effect of prolongation of the therapeutic effect is observed due to the release of the active substance from the non-decomposing matrix. This fact can be confirmed by both pharmacopoeial and non-pharmacopoeial methods. The classic tests regulated by the Pharmacopoeia of the XV edition include the "Dissolution" test (GPM.1.4.2.0014 "Dissolution of solid pharmaceutical dose forms"), and for non–pharmacopoeial ones – dialysis through a semipermeable membrane according to Kruvchinsky or using Franz's dialysis cells. The analysis of the kinetics of dissolution helps to determine and select the most suitable matrix-forming agent to be used in the composition with other substances in the composition of ocular insert. Ocular inserts with a biodegradable matrix have a second factor that affects the release of active substances – the formation of complexes or associates between parts of the matrix and the active ingredient molecules. These intermolecular compounds can indirectly prolong the effect of the drug. All features must be taken into account in the development of ocular inserts, since they, among other things, help to model fundamentally new ways of targeted delivery of substances. In this case, it is necessary to develop a test for the second modified release factor, which would reliably determine the presence of complexation processes within the selected ocular inserts model.

Unveiling Dissolution Kinetics of CuO Nanofertilizer Using Bio-Based Ionic Liquids Envisaging Controlled Use Efficiency for Sustainable Agriculture.

The need for sustainable agriculture amid a growing population and challenging climatic conditions is hindered by the environmental repercussions of widespread fertilizer use, resulting in the accumulation of metal ions and the loss of micronutrients. The present study provides an approach to improve the efficiency of nanofertilizers by controlling the release of copper (Cu) ions from copper oxide (CuO) nanofertilizers through bioionic liquids based on plant growth regulators (PGR-ILs). A 7-day study was conducted to understand the kinetics of Cu ion release in aqueous solution of five different PGR-ILs, with choline ascorbate ([Cho][Asc]) or choline salicylate ([Cho][Sal]) leading to 200- to 700-fold higher dissolution of Cu ions in comparison to choline indole-3-acetate ([Cho][IAA]), choline indole-3-butyrate ([Cho][IBA]), and choline gibberellate ([Cho][GA3]). The tunable diffusion of Cu ions from CuO nanofertilizers using PGR-ILs is then applied in a foliar spray study, evaluating its impact on the growth phenotype, photosynthetic parameters, and carbon dioxide (CO2) sequestration in Nicotiana tabacum in a greenhouse. The results indicate that nanoformulations with lower concentrations of Cu ions in PGR-IL solutions exhibit superior outcomes in terms of plant length, net photosynthetic rate, dry biomass yield, and CO2 sequestration, emphasizing the critical role of dissolution kinetics in determining the effectiveness of PGR-IL-based nanoformulations for sustainable agriculture.

Tracking the Cellular Degradation of Silver Nanoparticles: Development of a Generic Kinetic Model.

Understanding the degradation of nanoparticles (NPs) after crossing the cell plasma membrane is crucial in drug delivery designs and cytotoxicity assessment. However, the key factors controlling the degradable kinetics remain unclear due to the absence of a quantification model. In this study, subcellular imaging of silver nanoparticles (AgNPs) was used to determine the intracellular transfer of AgNPs, and single particle ICP-MS was utilized to track the degradation process. A cellular kinetic model was subsequently developed to describe the uptake, transfer, and degradation behaviors of AgNPs. Our model demonstrated that the intracellular degradation efficiency of AgNPs was much higher than that determined by mimicking testing, and the degradation of NPs was highly influenced by cellular factors. Specifically, deficiencies in Ca or Zn primarily decreased the kinetic dissolution of NPs, while a Ca deficiency also resulted in the retardation of NP transfer. The biological significance of these kinetic parameters was strongly revealed. Our model indicated that the majority of internalized AgNPs dissolved, with the resulting ions being rapidly depurated. The release of Ag ions was largely dependent on the microvesicle-mediated route. By changing the coating and size of AgNPs, the model results suggested that size influenced the transfer of NPs into the degradation process, whereas coating affected the degradation kinetics. Overall, our developed model provides a valuable tool for understanding and predicting the impacts of the physicochemical properties of NPs and the ambient environment on nanotoxicity and therapeutic efficacy.

Evaluation of novel carriers for enhanced dissolution of lycopene

Despite the antioxidant properties of lycopene, its poor water solubility reduces its efficiency and bioavailability. The study aimed to enhance the solubility of lycopene to improve its efficiency. To make lycopene more soluble, different carriers were added using physical mixing and solid-dispersion techniques. Then, the mechanisms of this solubility improvement were studied using solid-state characterization and docking studies. Out of 56 polymers and their combinations, isolated protein-whey (IWP) and polyvinylpyrrolidone-K30 (PVP-K30) showed the highest solubility for lycopene. These particles exhibited a more negative surface charge and a lower polydispersity index. Dissolution kinetics revealed that using IPW resulted in the highest release rate of lycopene. It was found that lycopene and β-lactoglobulin, an IPW component, have a hydrophobic bond. This makes a hydrophilic coating around the lycopene molecule. DSC results showed that lycopene could be in an amorphous state in IPW-lycopene formulations. The results of this study show how some food ingredients can improve the bioavailability of drugs that don’t dissolve well in water. This will help with future efforts to deliver drugs.

RAPID DISSOLUTION: DEVELOPMENT AND ASSESSMENT OF A NOVEL DRUG FORMULATION

This study focuses on the development and assessment of a novel fast-dissolving drug formulation aimed at improving drug delivery efficiency and patient compliance. The formulation was designed to dissolve rapidly in the oral cavity, facilitating quick absorption and onset of action. Through a systematic approach, the formulation's composition, including excipients and active pharmaceutical ingredients, was optimized to achieve rapid dissolution while maintaining stability and bioavailability. Various techniques, such as direct compression, freeze-drying, and spray drying, were explored to produce the fast-dissolving drug formulation. Evaluation of the formulation involved assessments of dissolution kinetics, drug release profile, physical characteristics, and pharmacokinetic parameters. The results demonstrate the potential of the fast-dissolving drug formulation to offer enhanced drug delivery and improved patient experience, making it a promising option for pharmaceutical development.

Kinetic investigation of sulfur corrosion: First principles calculations

The expressions of two important kinetic parameters (chemical activation energy of electrode reaction and absolute potential of equilibrium state) that determine the reaction rate during the anodic dissolution reaction are derived from the thermodynamic and kinetic relationships of the anodic dissolution reaction, the relationship between absolute potential and current density in the anode dissolution process is constructed. Under the framework of first principles, the calculation model of the electrochemical corrosion anodic dissolution reaction is proposed. Density functional theory study of the process of dissolving Fe atoms from the surface of Fe(111) alloy models in vacuum and explicit water molecules. The addition of water molecules and sulfur atoms promotes charge transfer during dissolution and increases the corrosion rate, while water molecules reduce the work function, while S goes increases the work function. Through the corrosion current density model of activation energy, the role of alloy dissolution kinetics with different alloys added was explored. The analysis shows that the addition of Mn and Cr can greatly reduce the anodic corrosion rate and increase the corrosion resistance of Fe.

Dissolution of gas in a stationary liquid layer: A diffusion-kinetic model and experimental studies

An analytic model of gas dissolution in a stationary liquid layer is presented. This model considers for the first time the intrinsic kinetics of the process of gas dissolution in a liquid characterized by the rate of gas absorption/desorption reaction at the gas–liquid interface. Within the framework of the presented model, it is shown that the process of gas dissolution in a stationary liquid layer occurs either in the diffusion-kinetic regime or in the diffusion regime. In the diffusion-kinetic regime, the rate of gas dissolution in a stationary liquid layer is affected by both the intensity of gas diffusion through the liquid layer and the intrinsic kinetics of the gas dissolution process in the liquid; in the diffusion regime, the rate of gas dissolution in a stationary liquid layer is limited only by the intensity of gas diffusion through the liquid layer. Experiments were carried out to study the kinetics of methane dissolution in a stationary layer of water at different temperatures. From the comparison of calculated and experimental data, the values of the diffusion coefficient of methane in water were determined, and it was also established that the process of methane dissolution in a stationary layer of water occurs in the diffusion regime. A new empirical correlation for calculating the diffusion coefficient of methane in water in the temperature range from 273 to 323.15 K was obtained based on our and available data points: D[m2/s]=exp(−12.64−2250.5/T[K]).

Controlling the lifetime of biodegradable electronics: from dissolution kinetics to trigger acceleration

Biodegradable electronics have revolutionized the field of medical devices by offering inherent advantages such as natural disintegration after a useful functional period, thereby eliminating the need for removal surgery. This paradigm shift addresses challenges with long-term implantation, the risks of secondary surgeries, and potential complications, offering a safer and more patient-friendly approach to temporary implantable devices. This review delves into the dissolution kinetics of materials and strategies for lifetime control providing a comprehensive overview of recent advancements in biodegradable electronics. Understanding the kinetics is crucial for meeting the required functional lifetime for implantable medical applications, which varies based on application scope and target diseases. The dissolution kinetics of silicon and biodegradable metals form the core of the discussion, focusing on recent studies aimed at controlling the dissolution rate and enhancing properties. The exploration extends to ideas for accelerating material degradation or initiating on-demand degradation in biodegradable electronics after stable function. Additionally, the compilation of encapsulation layer materials and strategies enhances understanding of how to improve the stable operation time of devices. Emphasis is placed on efforts to adjust the lifetime of biodegradable electronics, particularly in medical applications.

Dissolvable microneedles in the skin: Determination the impact of barrier disruption and dry skin on dissolution

Dissolvable microneedles (DMNs), fabricated from biocompatible materials that dissolve in both water and skin have gained popularity in dermatology. However, limited research exists on their application in compromised skin conditions. This study compares the hyaluronic acid-based DMNs penetration, formation of microchannels, dissolution, and diffusion kinetics in intact, barrier-disrupted (tape stripped), and dry (acetone-treated) porcine ear skin ex vivo. After DMNs application, comprehensive investigations including dermoscopy, stereomicroscope, skin hydration, transepidermal water loss (TEWL), optical coherence tomography (OCT), reflectance confocal laser scanning microscopy (RCLSM), confocal Raman micro-spectroscopy (CRM), two-photon tomography combined with fluorescence lifetime imaging (TPT-FLIM), histology, and scanning electron microscopy (SEM) were conducted. The 400 µm long DMNs successfully penetrated the skin to depths of ≈200 µm for dry skin and ≈200–290 µm for barrier-disrupted skin. Although DMNs fully inserted into all skin conditions, their dissolution rates were high in barrier-disrupted and low in dry skin, as observed through stereomicroscopy and TPT-FLIM. The dissolved polymer exhibited a more significant expansion in barrier-disrupted skin compared to intact skin, with the smallest increase observed in dry skin. Elevated TEWL and reduced skin hydration levels were evident in barrier-disrupted and dry skins compared to intact skin. OCT and RCLSM revealed noticeable skin indentation and pronounced microchannel areas, particularly in barrier-disrupted and dry skin. Additional confirmation of DMN effects on the skin and substance dissolution was obtained through histology, SEM, and CRM techniques. This study highlights the impact of skin condition on DMN effectiveness, emphasizing the importance of considering dissolvability and dissolution rates of needle materials, primarily composed of hyaluronic acid, for optimizing DMN-based drug delivery.

Intercalating polypyrrole tuning interlayer space of V2O5 for advanced aqueous zinc ion batteries

Aqueous zinc-ion batteries is considered as a promising system for large scale electrochemical energy storage system owing to their intrinsic safety, and low cost. Nevertheless, the industrialization process is slow due to the constraints of high-performance cathode materials. Adjusting the layered structure of V2O5 through metal ion or polymer intercalation can effectively improve low electron conductivity, vanadium dissolution, and slow ion transport kinetics. Herein, the conductive polymer polypyrrole-intercalated V2O5·H2O (PVOH) was successfully prepared via simple hydrothermal method and following interface polymerization reaction. Getting benefit from the insertion of polypyrrole, the prepared PVOH composite material achieves a V2O5 cathode with a more open structure, rich active sites, and greater stability, allowing for an expanded crystal plane spacing of 14.5 Å. Therefore, the PVOH electrode demonstrates a discharge capacity of 475 mAh g−1 and a cycling stability of 95% capacity retention after 2000 cycles. The intercalating conductive polymers strategy can become a new approach to improve the electrochemical behavior of vanadium oxide cathodes.

Inhibition of Vanadium Cathode Dissolution in Zinc‐Ion Batteries on Thermodynamics and Kinetics by Guest Pre‐Intercalation

AbstractAqueous zinc‐ion batteries (AZIBs), recognized for their safety and environmental friendliness, hold significant promise for large‐scale energy storage. However, the rapid capacity degradation resulting from the dissolution of active cathode materials hampers the advancement of AZIBs. Here, Ru0.2V2O5∙0.41H2O (RuVO) is synthesized with remarkable capacity retention (98.2% over 5000 cycles at 10 A g−1). The pre‐intercalation of Ru3+ enhances the stability of both intrinsic and cycling structures, elevating the Gibbs free energy and suppressing V‐dissolution thermodynamically. Additionally, Ru3+ intercalation modulates the potential energy surface of Zn2+ migration, leading to the dominance of Zn2+ in the insertion/extraction mechanism, thereby kinetically impeding the dissolution reaction. This study elucidates the dissolution thermodynamics and kinetics of V‐based cathodes through a combination of experiments, mechanism analyses, and density functional theory (DFT) calculations.

Insights into the Mechanism of Enhanced Dissolution in Solid Crystalline Formulations.

Solid dispersions are a promising approach to enhance the dissolution of poorly water-soluble drugs. Solid crystalline formulations show a fast drug dissolution and a high thermodynamic stability. To understand the mechanisms leading to the faster dissolution of solid crystalline formulations, physical mixtures of the poorly soluble drugs celecoxib, naproxen and phenytoin were investigated in the flow through cell (apparatus 4). The effect of drug load, hydrodynamics in the flow through cell and particle size reduction in co-milled physical mixtures were studied. A carrier- and drug-enabled dissolution could be distinguished. Below a certain drug load, the limit of drug load, carrier-enabled dissolution occurred, and above this value, the drug defined the dissolution rate. For a carrier-enabled behavior, the dissolution kinetics can be divided into a first fast phase, a second slow phase and a transition phase in between. This study contributes to the understanding of the dissolution mechanism in solid crystalline formulations and is thereby valuable for the process and formulation development.

Enhanced Solubility of Ibuprofen by Complexation with β-Cyclodextrin and Citric Acid.

The ability of β-CD to form inclusion complexes with ibuprofen (IBU) and at the same time to make a two-phase system with citric acid was explored in the present study for achieving improved solubility and dissolution rate of IBU. Mechanical milling as well as mechanical milling combined with thermal annealing of the powder mixtures were applied as synthetic methods. Solubility and dissolution kinetics of the complexes were studied in compliance with European Pharmacopoeia (ICH Q4B). β-CD and citric acid (CA) molecules were shown to interact by both ball milling (BM), thermal annealing, as well as BM with subsequent annealing. Complexes were also formed by milling the three compounds (β-CD, CA and IBU) simultaneously, as well as by a consecutive first including IBU into β-CD and then binding the formed β-CD/IBU inclusion complex with CA. As a result, ternary β-CD/IBU/CA complex formed by initial incorporation of ibuprofen into β-CD, followed by successive formation of a two-phase mixture with CA, exhibited notably improved dissolution kinetics compared to the pure ibuprofen and slightly better compared to the binary β-CD/IBU system. Although the addition of CA to β-CD/IBU does not significantly increase the solubility rate of IBU, it must be considered that the amount of β-CD is significantly less in the ternary complex compared to the binary β-CD/IBU.

Investigation of an indigenous chalcopyrite ore leaching in ammonia solution: characterization, leaching and kinetics

ABSTRACT Chalcopyrite ore is one of the most abundant and pertinent oxidized copper minerals. In this research, the dissolution kinetics of chalcopyrite in an ammonia solution was examined. During leaching, the influences of leachant concentration, temperature, and particle diameter on the extent of copper ore dissolution were investigated. However, it was affirmed that the dissolution efficiency of chalcopyrite ore increased with decreasing particle fraction and increasing reaction temperature and ammonia concentration. About 68.6% copper ore dissolution was achieved with 2.0 mol/L NH3, 75 ºC reaction temperature, and 45 μm particle diameter within 120 minutes. The dissolution reaction mechanism was found to be described by diffusion-control with a calculated activation energy of 32.26 kJ/mol. In the XRD spectra of the residual product obtained at established conditions, CuFeS2 peaks were absent, indicating the leachability of the sample. Hence, the leach residue could serve as an important by-product for some local industries.

Crystal size, shape, and conformational changes drive both the disappearance and reappearance of ritonavir polymorphs in the mill

Organic compounds can crystallize in different forms known as polymorphs. Discovery and control of polymorphism is crucial to the pharmaceutical industry since different polymorphs can have significantly different physical properties which impacts their utilization in drug delivery. Certain polymorphs have been reported to 'disappear' from the physical world, irreversibly converting to new ones. These unwanted polymorph conversions, initially prevented by slow nucleation kinetics, are eventually observed driven by significant gains in thermodynamic stabilities. The most infamous of these cases is that of the HIV drug ritonavir (RVR): Once its reluctant form was unwillingly nucleated for the first time, its desired form could no longer be produced with the same manufacturing process. Here we show that RVR's extraordinary disappearing polymorph as well as its reluctant form can be consistently produced by ball-milling under different environmental conditions. We demonstrate that the significant difference in stability between its polymorphs can be changed and reversed in the mill-a process we show is driven by crystal size as well as crystal shape and conformational effects. We also show that those effects can be controlled through careful design of milling conditions since they dictate the kinetics of crystal breakage, dissolution, and growth processes that eventually lead to steady-state crystal sizes and shapes in the mill. This work highlights the huge potential of mechanochemistry in polymorph discovery of forms initially difficult to nucleate, recovery of disappearing polymorphs, and polymorph control of complex flexible drug compounds such as RVR.

Effect of pH, CO2, and Organic Ligand on the Kinetics of Talc and Lizardite Dissolution

Effect of pH, CO2, and Organic Ligand on the Kinetics of Talc and Lizardite Dissolution

Simulated Start-Stop and the Impact of Catalyst Layer Redox on Degradation and Performance Loss in Low-Temperature Electrolysis

Stress tests are developed that focus on anode catalyst layer degradation in proton exchange membrane electrolysis due to simulated start-stop operation. Ex situ testing indicates that repeated redox cycling accelerates catalyst dissolution, due to near-surface reduction and the higher dissolution kinetics of metals when cycling to high potentials. Similar results occur in situ, where a large decrease in cell kinetics (>70%) is found along with iridium migrating from the anode catalyst layer into the membrane. Additional processes are observed, however, including changes in iridium oxidation, the formation of thinner and denser catalyst layers, and platinum migration from the transport layer. Increased interfacial weakening is also found, adding to both ohmic and kinetic loss by adding contact resistances and isolating portions of the catalyst layer. Repeated shutoffs of the water flow further accelerate performance loss and increase the frequency of tearing and delamination at interfaces and within catalyst layers. These tests were applied to several commercial catalysts, where higher loss rates were observed for catalysts that contained ruthenium or high metal content. These results demonstrate the need to understand how operational stops occur, to identify how loss mechanisms are accelerated, and to develop strategies to limit performance loss.