Greater Solubility Research Articles

Synthesis and characteristics properties of lignified PVA copolymer with enhanced UV-blocking performance and water solubility

The increasing environmental concerns have heightened the pursuit of sustainable materials, with a particular emphasis on biodegradable polymers. Polyvinyl alcohol (PVA), a recognized biodegradable synthetic polymer, faces challenges such as cost, slow biodegradation, and limited UV resistance. This study explores lignin, an abundant and eco-friendly biopolymer, as a cost-effective additive to enhance PVA properties via the copolymerization technique. The Mannich reaction was utilized to effectively alkylate lignin with allylthiourea, leading to the synthesis of a lignin-based macromonomer (LATU). Subsequently, the LATU macromonomer was copolymerized with vinyl acetate, producing Poly(VAc-Co-LATU) copolymer in a reaction conducted at 70 °C for 6 h. Finally, the copolymers were hydrolyzed (saponification) with potassium hydroxide to obtain Poly(VA-Co-LATU) copolymers. Extensive investigations, including FTIR, XPS, XRD, and 1H NMR, effectively validated the synthesis of the copolymers. The high monomer conversion rate above 89 % emphasizes the effectiveness of the synthesis method. The addition of LATU has a direct impact on the crystalline structure of the copolymer. X-ray diffraction patterns indicate a reduction in crystallinity, which in turn affects the other properties of the synthesized copolymers. Consequently, the lignified copolymer, Poly(VA-co-LATU), exhibited slight decrease in molecular weight (Mw), improved UV-blocking effectiveness, and greater solubility in water as comparison to PVA. This study demonstrates the feasibility of using lignin as a monomer to create novel bio-based polymeric materials that exhibit the necessary properties for certain applications.

Synergistic effects of β-Cyclodextrin derivative inclusion complexes with favipiravir to enhance solubility and antiviral efficacy against Herpes Simplex virus type 1 (HSV-1)

In this study, the formation of β-cyclodextrin derivatives (β-Cyclodextrin; β-CD, Hydroxypropyl-β-Cyclodextrin; Hβ-CD, and Sulfobutylether-β-Cyclodextrin; Sβ-CD) inclusion complexes with favipiravir (FPR) was confirmed using various spectroscopic and analytical techniques. These complexes were shown to enhance FPR solubility and antiviral activity against herpes simplex virus type 1 (HSV-1). UV–visible and fluorescence spectroscopy revealed a continuous increase in FPR absorbance and fluorescence intensity with increasing β-CD concentrations, indicating the successful formation of 1:1 inclusion complexes. The prepared β-CD solid complexes were characterized using FTIR, XRD, FESEM, and TGA-DSC, which highlighted significant surface properties, morphological changes, and improved thermal stability. Phase solubility studies demonstrated enhanced FPR solubility in the presence of the β-CDs, with stability constants (Ks) following the order: Hβ-CD (694.8 M−1) > Sβ-CD (418.4 M−1) > β-CD (364.3 M−1). In-vitro release studies showed that the Hβ-CD complex achieved a higher cumulative release of 90.16 ± 1.94 % over 90 min compared to free FPR (25.32 ± 0.29 %), attributed to its greater solubility. Molecular docking provided insights into the interaction mechanisms, revealing higher binding affinities and stability for FPR with β-CD. In-vitro antiviral assays against HSV-1 demonstrated significant viral titer reductions for free FPR with β-CDs, with Hβ-CD outperforming others due to its rapid release profile after 96 h of incubation, confirming its potential for improved antiviral formulations. The cytotoxic effects of FPR and its β-CDs inclusion complexes were evaluated on Vero cells using an MTT assay over 96 h, showing reduced cytotoxicity for the inclusion complexes compared to free FPR. Additionally, cellular uptake studies revealed that β-CDs inclusion complexes conjugated with DAPI and FITC exhibited greater intensity within Vero cells compared to free FPR.

Nanostructures for Delivery of Flavonoids with Antibacterial Potential against Klebsiella pneumoniae.

Flavonoids are secondary metabolites that exhibit remarkable biological activities, including antimicrobial properties against Klebsiella pneumoniae, a pathogen responsible for several serious nosocomial infections. However, oral administration of these compounds faces considerable challenges, such as low bioavailability and chemical instability. Thus, the encapsulation of flavonoids in nanosystems emerges as a promising strategy to mitigate these limitations, offering protection against degradation; greater solubility; and, in some cases, controlled and targeted release. Different types of nanocarriers, such as polymeric nanoparticles, liposomes, and polymeric micelles, among others, have shown potential to increase the antimicrobial efficacy of flavonoids by reducing the therapeutic dose required and minimizing side effects. In addition, advances in nanotechnology enable co-encapsulation with other therapeutic agents and the development of systems responsive to more specific stimuli, optimizing treatment. In this context, the present article provides an updated review of the literature on flavonoids and the main nanocarriers used for delivering flavonoids with antibacterial properties against Klebsiella pneumoniae.

Carbon Dots: A Versatile Platform for Cu2+ Detection, Anti-Counterfeiting, and Bioimaging.

Carbon dots (CDs) have garnered extensive interest in basic physical chemistry as well as in biomedical applications due to their low cost, good biocompatibility, and great aqueous solubility. However, the synthesis of multi-functional carbon dots has always been a challenge for researchers. Here, we synthesized novel CDs with a high quantum yield of 28.2% through the straightforward hydrothermal method using Diaminomaleonitrile and Boc-D-2, 3-diaminopropionic acid. The size, chemical functional group, and photophysical properties of the CDs were characterized by TEM, FTIR, XPS, UV, and fluorescence. It was demonstrated in this study that the prepared CDs have a high quantum yield, excellent photostability, and low cytotoxicity. Regarding the highly water-soluble property of CDs, they were proven to possess selective and sensitive behavior against Cu2+ ions (linear range = 0-9 μM and limit of detection = 1.34 μM). Moreover, the CDs were utilized in fluorescent ink in anti-counterfeiting measures. Because of their low cytotoxicity and good biocompatibility, the CDs were also successfully utilized in cell imaging. Therefore, the as-prepared CDs have great potential in fluorescence sensing, anti-counterfeiting, and bioimaging.

Enhanced molecular stability of ApxII antigen during secretion in Corynebacterium glutamicum by rational design

ApxII is a vaccine antigen used to protect against porcine contagious pleuropneumonia, which is a significant threat to the pig industry. Here, we aimed to improve the proteolytic degradation stability of ApxII during its secretion by establishing a complete screening process of stable variants through bioinformatics and site-directed mutagenesis. We employed a combination of semi-rational and rational design strategies to create 34 single-point variants of ApxII. Among them, R114E and T115D variants exhibited better stability without compromising antigen activity. Furthermore, we constructed a multi-site variant, R114E/T115D, which demonstrated the best stability, activity, and yield. Protein stability and molecular dynamic analysis indicated that the greater solubility and lower structural expansion coefficient might explain the increased stability of R114E/T115D. Additionally, site T115 was identified as a key point of truncated ApxII stability. The R114E/T115D variant, with its proven stability and intact antigenic activity, holds promising prospects for industrial-scale applications in the prevention of porcine contagious pleuropneumonia.

Pegylated Viologen Derivatives to Improve Performance of Aqueous Organic Redox Flow Battery

Renewable energy sources like wind and solar power are great alternatives for a clean way to produce electricity but have the inconvenience to fluctuate1. To address this issue and promote the implementation of renewables sources, scientists are developing new ways to store energy while production is at a maximum for a subsequent release when there is demand. Redox flow batteries (RFBs) are the most appropriate solution and are increasingly gaining attention for stationary, large scale electrochemical energy storage2,3. One variation of RFBs are aqueous organic redox flow batteries (AORFBs), where water-soluble organic molecules are use as the redox couple. Viologen type molecules are particularly well-suited as a negative potential species to develop cheaper and better AORFBs with great scalability, reversibility and long-term stability4.In this study, viologen derivatives were synthesized with various N-functional groups to explore the impact of the substituent on their solubility, viscosity and redox potential. We showed that the use of short chains of poly(ethylene glycol) improved the solubility of the viologens derivatives which could lead to batteries with higher capacity. The symmetric viologen (with two identical substituents) provided a great solubility in water and the formal potential was unaffected by the chemical nature of the substituents. We demonstrated that the 1,1’-(bisethylene glycol)-4,4’-bipyridium (PEG2-V-PEG2) showed the most promising properties with a high solubility (2.3 M in 1M KCl) and low viscosity (3.01 mPa*s at 1M). As such, this derivative was selected for further evaluation in an asymmetrical labs-scale RFB prototype cell versus bis(trimethylamoniumpropyl)ferrocene (BTMAP-Fc). The compound was studied at various concentrations to assess the maximum energy density that can be reached and the effect of concentration on cycling life by achieving a comparison to the symmetrical 1,1’-bis(3-sulfonatopropyl)-4,4’-bipyridium (SPr-V-SPr) at 0.5 M. Figure 1: Redox flow battery scheme using Viologen derivative as the negolyte and BTMAP-Fc as the posolyte Reference Shi, X., Qian, Y. and Yang, S. Fluctuation analysis of a complementary wind–solar energy system and integration for large scale hydrogen production. ACS Sustainable Chemistry & Engineering, 8(18), pp.7097-7110. (2020)Sánchez-Díez, E.; Ventosa, E.; Guarnieri, M.; Trovò, A.; Flox, C.; Marcilla, R.; Soavi, F.;Mazur, P.; Aranzabe, E.; Ferret, R., Redox flow batteries: Status and perspective towards sustainable stationary energy storage. Journal of Power Sources, 481, 1-23. (2021)Poullikkas, A., A comparative overview of large-scale battery systems for electricity storage. Renewable and Sustainable energy reviews, 27, pp.778-788. (2013)Gentil, S., Reynard, D. and Girault, H.H. Aqueous organic and redox-mediated redox flow batteries: a review. Current Opinion in Electrochemistry, 21, pp.7-13. (2020) Figure 1

Assembling-induced redox property adjustment of Fe(III)/Fe(IV) electroredox couple-based commercial dye catholyte via bio-inspired multicoordination sphere construction strategy for stable aqueous redox flow batteries

Redox flow batteries (RFBs) are capable of storing and integrating indirect clean energy. This is due to their scalability, safety, and reliability, as well as their independent decoupling of power and energy. Aqueous organic redox flow batteries (AORFBs) have redox-active materials that are composed of abundant elements, have tunable redox potential, greater solubility, and lower cost. Here We propose the use of an inexpensive commercial dye, naphthol green B (NGB), as a catholyte material for AORFBs. This is the first time that NGB has been utilized in the Fe(III)/Fe(IV) electroredox couple, demonstrating a high redox potential of 0.73 V vs. NHE under neutral conditions. Experimental characterizations and theoretical simulations indicate that hydroxypropyl-β-cyclodextrin (HP-β-CD) can serve as the secondary and outer coordination sphere of NGB, enhancing its electrochemical performance and stability, while also preventing transmembrane crossover. In the NGB/K3Fe(CN)6 test with HP-β-CD symmetric battery, NGB demonstrated excellent electrochemical stability. When used as anolyte with 1,1′-bis(3-sulfonatopropyl)-4,4′-bipyridinium (Spr)2V, the NGB/(Spr)2V AORFB with HP-β-CD demonstrated exceptional cycling performance at current rates ranging from 5 to 30 mA cm−2. It is worth noting that the NGB/(Spr)2V AORFB maintained over 99 % of its total capacity or experienced less than 0.00125 % capacity decay per cycle, with an average Coulombic efficiency of almost 100 % over 800 cycles at 10 mA cm−2. NGB is a novel and superior catholyte that offers multiple options for studying AORFBs and the potential for large-scale energy storage applications.

Drying effects on physicochemical and functional properties of cuttlefish (Sepia officinalis) ink powder

This study investigated the physicochemical, functional, and organoleptic properties of cuttlefish (Sepia officinalis) ink powder prepared by freeze drying and hot air tray drying. Key proximate and physicochemical properties were measured to assess differences due to drying method. In addition, organoleptic tests were conducted on cuttlefish ink powder incorporated into spaghetti sauce. Freeze-dried powders had slightly higher moisture (9.86 %) than tray-dried powders (7.65 %) and more ash (15.04 versus 13.19 %). Both samples had ∼43 % protein, a light-brown to black color and a pH of 5.5–5.6 when rehydrated. There were no differences in loose or tapped density and Hausner ratios of 1.30–1.35 suggest the powders had ‘passable’ flow. Overall protein solubility varied with pH and freeze-dried materials generally had greater solubility. FT-IR showed no differences in peaks derived from organic components. FE-SEM showed both samples had spherical granules that formed 100–200 nm clusters; however, the surface texture of tray-dried powders was rougher than the freeze-dried samples. Consumer tests showed higher overall likability for spaghetti sauce with fresh ink compared to dried ink powders. Differences were attributed more to texture than to flavor or appearance. Cuttlefish ink can be utilized in the food industry, particularly as a natural flavor, food coloring or additive.

On the identification of favourable factors for corrosion inhibition of aluminium by 8-hydroxyquinoline and its derivatives: DFT and electrochemical studies

Computational and electrochemical experimental approaches were combined to identify factors which would be favourable or detrimental to corrosion inhibition of aluminium by 8-hydroxyquinoline (8Hq) and its sulfonic derivative (8HqSH). 8HqSH exhibited a strong adsorption on Al(111) but a greater solubility in water than 8Hq, including Al complexes, which might increase Al corrosion. This was confirmed by the electrochemical measurements. In the presence of 8HqSH, an acceleration of the aluminium dissolution was observed, whereas, in the presence of 8Hq, a protective film was formed on the Al surface.

Physicochemical properties and biological efficacy of 30 DYRK2 Inhibitors for the treatment of prostate cancer

AbstractProstate cancer is the most common cancer among men which has major diagnosis in the United States in 2017. Among DYRK class II members, dual specificity tyrosine phosphorylation‐regulated kinase 2 (DYRK2) is the functional target for prostate cancer treatment. Studies show that subfamilies of DYRKs are also capable to phosphorylate (tyrosine, serine, and threonine) residues, yet little research has been carried out for its inhibitors. In this article, conceptual density theory is used to estimate the physicochemical properties of 30 experimentally synthesized inhibitors targeting DYRK2. The HOMO–LUMO gap showed low reactivity and high chemical activity for the inhibitors. The biological efficacy of these 30 inhibitors is predicted by bioavailability, mutagenicity, and cardiotoxicity measures. The inhibitors showed low toxicity and no blood brain barrier permeability. Results indicated that the physiological actions of these inhibitors involve multiple target interactions. Since the experimental results of the DYRK2 protein showed great water solubility, favorable safety properties, and potential anti‐prostate cancer activities for ligand 24, docking and molecular dynamics simulations from the Galaxy webserver using Gromacs open‐source tools are also performed for (DYRK2‐24) complex (PDB: 7EJV). (DYRK2‐24) showed strong binding affinity and noncovalent interactions.

Weathering Incongruence in Mountainous Mediterranean Climates Recorded by Stream Lithium Isotope Ratios

AbstractLithium isotope ratios (δ7Li) of rivers are increasingly serving as a diagnostic of the balance between chemical and physical weathering contributions to overall landscape denudation rates. Here, we show that intermediate weathering intensities and highly enriched stream δ7Li values typically associated with lowland floodplains can also describe small upland watersheds subject to cool, wet climates. This behavior is revealed by stream δ7Li between +22.4 and +23.5‰ within a Critical Zone observatory located in the Cévennes region of southern France, where dilute stream solute concentrations and significant atmospheric deposition otherwise mask evidence of incongruence. The water‐rock reaction pathways underlying this behavior are quantified through a multicomponent, isotope‐enabled reactive transport model. Using geochemical characterization of soil profiles, bedrock, and long‐term stream samples as constraints, we evolve the simulation from an initially unweathered granite to a steady state weathering profile which reflects the balance between (a) fluid infiltration and drainage and (b) bedrock uplift and soil erosion. Enriched stream δ7Li occurs because Li is strongly incorporated into actively precipitating secondary clay phases beyond what prior laboratory experiments have suggested. Chemical weathering incongruence is maintained despite relatively slow reaction rates and moderate clay accumulation due to a combination of two factors. First, reactive primary mineral phases persist across the weathering profile and effectively “shield” the secondary clays from resolubilization due to their greater solubility. Second, the clays accumulating in the near‐surface profile are relatively mature weathering byproducts. These factors promote characteristically low total dissolved solute export from the catchment despite significant input of exogenous dust.

Multi-spectroscopies and molecular docking insights into the interaction mechanism and antioxidant activity of isoquercetin and zein nanoparticles

The purpose of this study was to compare and characterize the theoretical properties and interaction mechanisms of zein and isoquercetin (ISO) from experimental and theoretical perspectives. Zein nanoparticles with different ISO concentrations (ZINPs) were prepared by the antisolvent precipitation method. The experimental results indicated all particles appeared spherical. When the mass ratio of zein to ISO was 10:1, the encapsulation efficiency of ZINPs reached 88.19 % with an average diameter of 126.67 nm. The multispectral method and molecular docking results confirmed that hydrogen bonding and van der Waals force played a dominant role for the binding of ISO to zein, and the primary fluorescence quenching mechanism for zein by ISO was static quenching. Furthermore, ZINPs had greater solubility and antioxidant activity, as well as inhibited the release of ISO during simulated gastrointestinal digestion processes. This research contributes to the understanding of the non-covalent binding mechanism between zein and ISO, providing a theoretical basis for the construction of ISO active carriers.

Fluorescent molecular systems based on carborane-perylenediimide conjugates.

This study presents the successful synthesis of two perylenediimide (PDI)-based ortho-carborane (o-carborane) derivatives, PDI-CB1 and PDI-CB2, through the insertion of decaborane into alkyne-terminated PDIs (PDI1 and PDI2). The introduction of o-carborane groups did not alter the optical properties of the PDI units in solution compared to their carborane-free counterparts, maintaining excellent fluorescence quantum yields of around 100% in various solvents. This was achieved by using a methylene linker to minimize electronic interaction between PDI and o-carborane, and by incorporating bulky o-carborane groups at imide- position to enhance solubility and prevent π-π stacking-induced aggregation. Aggregation studies demonstrated that PDI-CB1 and PDI-CB2 have greater solubility than PDI1 and PDI2 in both nonpolar and aqueous solvents. Despite the steric hindrance imparted by the o-carborane units, the solid state emission of PDI-CB1 and PDI-CB2 was affected by aggregation-caused fluorescence quenching. However, solid PDI-CB1 preserved bright red excimer-type emission, which persisted in water-dispersible nanoparticles, indicating potential for application as a theranostic agent combining fluorescence bioimaging with anticancer boron neutron capture therapy (BNCT) due to its high boron content.

Using a systematic and quantitative approach to generate new insights into drug loading of PLGA nanoparticles using nanoprecipitation.

The synthesis of drug-loaded PLGA nanoparticles through nanoprecipitation in solvent/antisolvent mixtures is well reported but lacks clarity in explaining drug loading mechanisms and the prediction of efficiency of drug entrapment. Various methods using physical parameters such as log P and solid-state drug-polymer solubility aim to predict the intensity of drug-polymer interactions but lack precision. In particular, the zero-enthalpy method for drug/polymer solubility may be intrinsically inaccurate, as we demonstrate. Conventional measurement of loading capacity (LC), expressed in weight ratios, can be misleading for comparing different drugs and we stress the importance of using molar units. This research aims to provide new insights and critically evaluate the established methodologies for drug loading of PLGA nanoparticles. The study employs four model drugs with varying solubilities in solvent/antisolvent mixtures, log P values, and solid-state solubility in PLGA: ketoprofen (KPN), indomethacin (IND), sorafenib (SFN), and clofazimine (CFZ). This study highlights that drug loading efficiency is primarily influenced by the drug's solubilities within the solvent system. We emphasise that both kinetic and thermodynamic factors play a role in the behaviour of the system by considering the changes in drug solubility during mixing. The study introduces a pseudo-constant K* to characterise drug-polymer interactions, with CFZ and SFN showing the highest K* values. Interestingly, while IND and KPN have lower K* values, they achieve higher loading capacities due to their greater solubilities, indicating the key role of solubility in determining LC.

Effect of Gas Composition on Surfactant Injectivity in a Surfactant-Alternating-Gas Foam Process.

Aqueous foam is a dispersion of gas in liquid, where the liquid acts as the continuous phase and the gas is separated by thin liquid films stabilized by a surfactant. Foam injection is a widely used technique in various applications, including CO2 sequestration, enhanced oil recovery, soil remediation, etc. Surfactant-alternating-gas (SAG) is a preferred approach for foam injection, and injectivity plays a vital role in determining the efficiency of the SAG process. Different gases can be applied depending on the process requirements and availability. However, the underlying mechanisms by which gas composition impacts injectivity are not yet fully understood. In this work, the effect of gas composition on fluid behavior and injectivity in a SAG process was investigated using three gases: N2, CO2, and Kr. Our observations revealed that gas solubility in liquid was key for the formation and evolution of liquid fingers, and therefore was very important for liquid injectivity. A lower gas solubility in liquid led to a slower increase in surfactant solution injectivity. In addition, the development of surfactant solution injectivity took significantly longer when the surfactant solution was partially pre-saturated compared to when it was unsaturated. Additionally, the propagation of the collapsed-foam bank during gas injection was accelerated when the gas had a greater solubility in water.

Theoretical and experimental studies on sulfasalazine interactions with poly (lactic acid): Impact of hydrogen bonding and charge transfer interactions on molecular structure, electronic and optical properties

The interaction between sulfasalazine (SSZ) through different functional groups and poly (lactic acid) (PLA) in the chloroform phase was investigated in this study using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. The binding energy and thermodynamic parameters show that the hydrogen double bond interaction between SSZ and PLA in state I (−0.71 eV) is stronger than in states II (−0.64 eV) and III (−0.51 eV). The SSZ and PLA interaction results in an enhanced dipole moment, greater solubility, and more negative values for Gibbs free energy (ΔGsolv) and energy gap (Eg). Considerable changes in absorption peaks of SSZ and PLA indicate surface adsorption of the drug (SSZ) into the carrier (PLA) in UV–Vis spectra. Theoretical UV–Vis analysis demonstrates SSZ interaction with PLA happens in the ultraviolet region with a maximum absorption peak at 380 nm, which is close to experimental UV–Vis analysis. The experimental spectra showed minimal variations in the maximum absorption wavelength, with respect to theoretical calculations. The presence of SSZ was found to cause a modification in the structure of PLA, as evidenced by both experimental and theoretical Infrared (IR) spectra.

Catalytic oxidation of toluene using layer-modified Mn-Ce solid solution with high specific surface area

Numerous studies have been reported on the application of Mn-Ce catalysts for the catalytic oxidation of toluene, and the modification of their physical structure has become an important method to favour toluene adsorption. This paper modified (MnCe)Ox by using a series of organic solutions. The catalysts modified by different organic solutions were prepared for the catalytic oxidation of toluene by impregnation method with calcination at 500 °C. Activity test results showed that the MC-TPAOH catalyst modified by tetrapropylammonium hydroxide solution had the best catalytic performance, with T50 and T90 of 192 °C and 221 °C. The MnO2 species on the surface of the catalyst modified by the organic solution were in an amorphous state, and the solid-solution effect of Mn-Ce was enhanced. Tetrapropylammonium hydroxide has greater solubility in polar solvents due to its higher number of C atoms and exhibits stronger phase-transfer ability, which was favourable to the Mn-Ce interaction. The structural properties of the catalyst were modulated by lamellar modification, which increased the specific surface area and formed a porous structure. The redox capacity was greatly improved, and more oxygen vacancies were exposed on the surface, which was conducive to the migration of active oxygen species. Reactive oxygen species present on the catalyst surface were the basis for its excellent activity. This study modifies (MnCe)Ox by organic solution to avoid the introduction of impurity ions. It opens a new direction for the physical structure modulation of Mn-Ce composite oxides and lays a research foundation for the organic modification of Mn-Ce composite oxides.

Solubility determination and thermodynamic model analysis of nefopam hydrochloride in eight plain solvents and three binary solvents from 273.15 K to 323.15 K

Nefopam hydrochloride (NPH) is a non-narcotic analgesic with antipyretic, analgesic, and muscle relaxant effects. Solubility is an important molecular property that can inform the crystallization and purification of drugs. In the present study, NPH solubility was measured in eight plain solvents and three binary solvents at 273.15 K-323.15 K. Results showed that in the plain solvents, NPH had the greatest solubility in methanol and the least in acetone. The solubility in the solvent system of methanol + acetone and ethanol + acetone becomes greater with the increase of the molar fraction of the positive solvent, while it becomes greatest in the system of water + acetone when the molar fraction of the positive solvent is 0.8 and at molar fractions>0.8 the solubility begins to decrease, which may be owing to the existence of the phenomenon of co-solubility. NPH solubility in plain solvents and binary solvents is positively correlated with temperature. By XRD and TG-DSC, the crystal structure of NPH in solvent did not change and the weight loss and melting temperatures were 500.49 K and 518.34 K respectively, which were much higher than the experimental temperatures. Selection of Hansen solubility parameter to predict the solubility effect of NPH in different solvents. The analysis was carried out using five thermodynamic models, ranging from Modified Apelblat model, Buchowski-Ksiazaczak λh model, CNIBS/R-K model, Jouyban-Acree model and SUN model, to fit the solubility data, out of which Modified Apelblat model and CNIBS/R-K model had more accurate prediction results.

Solubility enhancement and evaluation of Cilnidipine using solid Dispersion techniques

The poor solubility of Cilnidipine leads to low bioavailability and limits its therapeutic efficacy. To develop a dosage form that is stable, effective and has a higher bioavailability. It is necessary to increase the solubility of such medications. The present study aimed to improve the solubility by solid dispersion technique of Cilnidipine by solid dispersion techniques. Solvent evaporation and melt fusion methods were used to prepare solid dispersions of the drug cilnidipine with various polymers. The solubility of these prepared solid dispersions was evaluated by FT-IR spectroscopy, Differential Scanning Colorimetry and X-ray diffraction. The greatest solubility, of 21.07 µg/mL, was found in the solid dispersion that was developed by solvent evaporation technique employing a combination of Cilnidipine and Poloxamer 188 in a 1:9 ratio. The current investigation showed that solid dispersion using Poloxamer 188 can be a potentially effective method to increase the solubility and rate of dissolution of cilnidipine.

Production and Characterization of Heme Iron Polypeptide from the Blood of Skipjack Tuna (Katsuwonus pelamis) Using Enzymatic Hydrolysis for Food Supplement Application.

Organic heme iron in the form of heme iron polypeptide (HIP) is a bioavailable form of iron that can be used for dietary supplements. However, one practical challenge with HIP is that the quality of HIP prepared with different batches of raw material could lead to HIP products with inconsistent characteristics. In this study, skipjack tuna blood, a by-product in canned tuna industry, was converted to HIP at different degrees of enzymatic hydrolysis. The variation in HIP physical-chemical characteristics from different batches was evaluated, including composition, solubility, and molecular weight distribution. It was found that the batch variation had no effect on HIP composition and solubility; however, the degree of hydrolysis (DH) and the size of peptides that interact with heme greatly influenced HIP solubility at pH 2. Tuna-HIP with a low DH (DH, 8%) had 1.76-fold greater solubility than tuna-HIP with a high DH (DH, 32%). High-performance liquid chromatography (HPLC) revealed that tuna-HIP with a low DH had a molecular weight ranging from 1 kDa to 5 kDa. In summary, HIP-derived tuna blood was found to contain 70.54 ± 3.22 mg/100 g of iron and exhibit good solubility at 58.0 ± 2.16% at pH 2. Thus, tuna-HIP with a low DH might be a suitable functional ingredient for iron fortification of food.