Simple Dissolution Research Articles

Spontaneous Formation of Polymeric Nanoribbons in Water Driven by π–π Interactions

AbstractA simple method was developed to produce polymeric nanoribbons and other nanostructures in water. This approach incorporates a perylene diimide (PDI) functionalized by triethylene glycol (TEG) as a hydrophobic supramolecular structure directing unit (SSDU) into the core of hydrophilic poly(N,N‐dimethylacrylamide) (PDMAc) chains using RAFT polymerization. All PDI‐functional polymers dissolved spontaneously in water, forming different nanostructures depending on the degree of polymerization (DPn): nanoribbons and nanocylinders for DPn=14 and 22, and spheres for DPn>50 as determined by cryo‐TEM and SAXS analyses. UV/Vis absorption spectroscopy was used to monitor the evolution of the PDI absorption signal upon dissolution. In solid form, all polymers show a H‐aggregate absorption signature, but upon dissolution in water, the shortest DPn forming nanoribbons evolved to show HJ‐aggregate absorption signals. Over time, the J‐aggregate band increased in intensity, while cryo‐TEM monitoring evidenced an increase in the nanoribbon's width. Heating the nanoribbons above 60 °C, triggered a morphological transition from nanoribbons to nanocylinders, due to the disappearance of J‐aggregates, while H‐aggregates were maintained. The study shows that the TEG‐PDI is a powerful SSDU to promote 2D or 1D self‐assembly of polymers depending on DPn through simple dissolution in water.

Spontaneous Formation of Polymeric Nanoribbons in Water Driven by π-π Interactions.

A simple method was developed to produce polymeric nanoribbons and other nanostructures in water. This approach incorporates a perylene diimide (PDI) functionalized by triethylene glycol (TEG) as a hydrophobic supramolecular structure directing unit (SSDU) into the core of hydrophilic poly(N,N-dimethylacrylamide) (PDMAc) chains using RAFT polymerization. All PDI-functional polymers dissolved spontaneously in water, forming different nanostructures depending on the degree of polymerization (DPn): nanoribbons and nanocylinders for DPn=14 and 22, and spheres for DPn>50 as determined by cryo-TEM and SAXS analyses. UV/Vis absorption spectroscopy was used to monitor the evolution of the PDI absorption signal upon dissolution. In solid form, all polymers show a H-aggregate absorption signature, but upon dissolution in water, the shortest DPn forming nanoribbons evolved to show HJ-aggregate absorption signals. Over time, the J-aggregate band increased in intensity, while cryo-TEM monitoring evidenced an increase in the nanoribbon's width. Heating the nanoribbons above 60 °C, triggered a morphological transition from nanoribbons to nanocylinders, due to the disappearance of J-aggregates, while H-aggregates were maintained. The study shows that the TEG-PDI is a powerful SSDU to promote 2D or 1D self-assembly of polymers depending on DPn through simple dissolution in water.

Liquid Ammonia: More than an Innocent Solvent for Zintl Anions.

Liquid ammonia as the original solvent for Zintl anions has been replaced by easier to handle or more versatile solvents in most recent Zintl chemistry. However, methodological advances have made it possible to structurally investigate the anions in ammoniate crystals via crystallography or in the solutions themselves via nuclear magnetic resonance. While in some cases liquid ammonia acts as an innocent solvent, it also provides different possibilities of direct involvement in chemical reactions. In addition to simple dissolution without changes to the anions observed in the solid starting materials, protonation of the anion, incongruent dissolution involving redox processes, and further oxidation and reduction products have been observed. The use of the solvent liquid ammonia under ambient pressure is limited to low temperatures, which in turn allows the monitoring of kinetically stabilized species, some of which cannot be accessed at higher temperatures. In this work, the available literature reports are summarized or referenced, and compounds that have been characterized as new ammoniate crystals are presented and contextualized. Innocent dissolution is observed for clusters involved in K2.9Rb5.1[Si4][Si9]·15NH3, Cs4Sn9·12NH3, Cs4Pb9·5NH3, and [Rb@[18]crown-6]2[Rb@[2.2.2]crypt]Rb[Ge9]·4NH3. Formal protonation of [Ge4]4- results in the crystallization of [Na@[2.2.2]crypt]2[H2Ge4]·3NH3. Tt52- (Tt = Sn or Pb) and HSi93- cannot be accessed in a binary solid state material but can be crystallized in co-crystals of PPh3 in [Rb@[2.2.2]crypt]2[Sn5][PPh3]2·NH3, [Rb@[2.2.2]crypt]2[Pb5][PPh3]2·NH3, and [K@[2.2.2]crypt]3[HSi9][PPh3]·5NH3.

Chemical recycling of mixed textile waste.

Globally, less than 0.5% of postconsumer textile waste is recycled, with the majority incinerated or ending up in landfills. Most postconsumer textiles are mixed fibers, complicating mechanical recycling due to material blends and contaminants. Here, we demonstrate the chemical conversion of postconsumer mixed textile waste using microwave-assisted glycolysis over a ZnO catalyst followed by solvent dissolution. This approach electrifies the process heat while allowing rapid depolymerization of polyester and spandex to their monomers in 15 minutes. A simple solvent dissolution enables the separation of cotton and nylon. We assess the quality of all components through extensive material characterization, discuss their potential for sustainable recycling, and provide a techno-economic analysis of the economic feasibility of the process.

Lead Bromide Complex in Tri-n-Octylphosphine Oxide Matrix with Bright Photoluminance and Exceptional Thermoplasticity.

Metal halide materials have recently drawn increasing research interest for their excellent opto-electronic properties and structural diversity, but their resulting rigid structures render them brittle and poor formability during manufacturing. Here we demonstrate a thermoplastic luminant hybrid lead halide solid by integrating lead bromide complex into tri-n-octylphosphine oxide (TOPO) matrix. The construction of the hybrid materials can be achieved by a simple dissolution process, in which TOPO molecules act as the solvents and ligands to yield the monodispersed clusters. The combination of these functional units enables the near-room-temperature melt-processing of the materials into targeted geometry by simple molding or printing techniques, which offer possibilities for fluorescent writing inks with outstanding self-healing capacity to physical damage. The intermarriage between metal halide clusters with functional molecules expands the range of practical applications for hybrid metal halide materials.

Bioequivalence prediction with small-scale biphasic dissolution and simultaneous dissolution-permeation apparatus—An aripiprazole case study

Both biphasic dissolution and simultaneous dissolution-permeation (D-P) systems have great potential to improve the in vitro-in vivo correlation compared to simple dissolution assays, but the assay conditions, and the evaluation methods still need to be refined in order to effectively use these apparatuses in drug development.Therefore, this comprehensive study aimed to compare the predictive accuracy of small-volume (16–20 mL) D-P system and small-volume (40–80 mL) biphasic dissolution apparatus in bioequivalence prediction of five aripiprazole (ARP) containing marketed drug products.Assay conditions, specifically dose dependence were studied to overcome the limitations of both small-scale systems. In case of biphasic dissolution the in vivo maximum plasma concentration (Cmax) prediction greatly improved with the dose reduction of ARP, while in case of the D-P setup the use of whole tablet gave just as accurate prediction as the scaled dose. With the dose reduction strategy both equipment was able to reach 100 % accuracy in bioequivalence prediction for Cmax ratio. In case of the in vivo area under the curve (AUC) prediction the predictive accuracy for the AUC ratio was not dependent on the dose, and both apparatus had a 100 % accuracy predicting bioequivalence based on AUC results.This paper presents for the first time that not only selected parameters of flux assays (like permeability, initial flux, AUC value) were used as an input parameter of a mechanistic model (gastrointestinal unified theory) to predict absorption rate but the whole in vitro flux profile was used. All fraction absorbed values estimated by Predictor Software fell within the ±15 % acceptance range during the comparison with the in vivo data.

Hydrogeochemistry and Quality Assessment using Water Quality Indices of Surface and Groundwater of Konar Reservoir Region, Hazaribag District, Jharkhand, India

ABSTRACT In the present paper, the water quality of the Konar reservoir area in the Hazaribag district of Jharkhand, India, has been investigated and with this view, the different physico-chemical variables, including pH, Dissolved Oxygen, Electrical Conductivity, TDS, Temperature, cations (Ca2+, Mg2+, Na+, K+), anions (CO32−, HCO3−, Cl−, F−, SO42−, NO3−) have been analyzed. According to Schoeller diagram, the order of major cations and anions for groundwater are Ca2+ > Na+ > Mg2+ > K+ and HCO3− > SO42− > Cl− > NO3− and for surface water are Na+ > Ca2+ > Mg2+ > K+ and Cl− > HCO3− > NO3− > SO42− respectively. The calculated water quality index shows that 100% of the samples of surface water are of excellent water quality, while 17% of the samples of groundwater are of excellent and 83% fall under the good category. The Gibbs Plot indicates that the rock-water interaction mechanism is dominant, Giggenbach triangle indicates that the waters have not yet reached equilibrium and are still in an immature state, although the Piper plot demonstrates that most of the surface water samples (78%) are mixed facies of Ca2+-Mg2+-Cl− and 22% are of Na+–Cl− type. All groundwater samples are mixed facies of Ca2+– HCO3− type. According to the Durov plot, 100% of surface water samples exhibit simple dissolution or mixing and majority of the ions in all groundwater samples are calcium and bicarbonate, showing the influence of limestone deposits. Almost all of the water samples from the Konar reservoir area were found to be appropriate for irrigation, according to the Residual Sodium Carbonate, Residual Sodium Bicarbonate, Sodium Percentage, Permeability Index, Kelley’s Ratio, Sodium Adsorption Ratio, United States Salinity Laboratory (USSL) and Wilcox diagrams.

Assessment of hydrochemical characteristics and trace metals of Punpun River water – a tributary of the Ganga River

ABSTRACT This manuscript presents the first inventory of dissolved ions (cations and anions) and trace metals (Pb, Mn, Cr, Co, Ni, Cu and Zn) in the Punpun River water to assess its irrigational suitability, pollution sources and hydrogeochemical processes. For this, the physicochemical parameters and trace metals in river water were analysed in the pre- and post-monsoon seasons. The results showed that the concentrations of cations and anions were Ca2+ > Na+ > Mg2+ > K+ and HCO3− > SO42- > Cl− > NO3− > PO43-, respectively, in both the pre- and post-monsoon seasons. However, trace metal concentration in pre- and post-monsoon followed the trend of Pb > Mn > Cr > Ni > Cu > Zn > Co and Pb > Ni > Mn > Cr > Zn > Co > Cu, respectively. The results reveal that combined effects of rock weathering and evaporation-concentration influence hydrochemistry, along with anthropogenic factors like industrial effluents, urban domestic sewage and agricultural runoff. Piper and Durov plots suggest that the river water is dominated by Ca–Mg–HCO3− type, and the processes were governed by simple ion dissolution and mixing. However, the Gibbs plot shows that silicate and carbonate weathering govern the hydrochemical properties. Irrigational indices like sodium adsorption ratio, %Na, residual sodium carbonate, Kelly's ratio, magnesium hazard, and trace metals indicate that most of the water samples are suitable for irrigation. Comprehensive pollution index values suggest that the river water quality ranges from sub-clean to slightly to moderately polluted.

Enzymatic Fat Dissolution Improves Detection of Small Lymph Nodes in Colon Cancer Surgery.

Background Accurate lymph node evaluation is essential for staging colon cancer and guiding postoperative treatment decisions. In this study, we compared the efficacy of a simple enzymatic fat dissolution method with the conventional method for lymph node sampling from specimens after colon cancer surgery. Methods We enrolled 58 patients who underwent elective laparoscopic surgery for colon adenocarcinoma between May 2018 and May 2021 at Fukuoka University Hospital in Fukuoka, Japan. The specimens from these patients were treated using fat dissolution and were compared with specimens from 58 patients for which conventional manual palpation was used. Results A significantly greater number of lymph nodes were detected by the fat dissolution method compared with the conventional method (average per patient, 27.5 vs. 22.6, P = 0.02). In particular, the between-group difference was significant for lymph nodes measuring <5 mm (average per patient, 26.1 vs. 20.9; P = 0.01). Multivariate analysis showed that, compared with the conventional method, the fat dissolution method was significantly associated with the identification of lymph node metastasis. The positive rate of lymph nodes ≥10 mm in diameter was markedly higher along the inferior mesenteric artery than the ileocolic artery (100% vs. 52.6%). Conclusions The use of the fat dissolution method led to an increase in the number of small lymph nodes detected. Rates of metastasis according to lymph node size may depend on the lymph node station.

Evaluation of Geology and Hydrochemistry of Nawfia-Agulu Axis of Anambra State, Southeastern Nigeria

The investigation of the geological, hydrochemical, and engineering characteristics of the Nawfia – Agulu area was carried out. The study aimed at mapping the geology through field data collection, outcrop logging, and laboratory analysis. Consequently, eleven soil and ten water samples were collected and analyzed through particle size distribution test; Atterberg limits tests and hydrochemical analysis to provide insights into the lithology, sediment characteristics, and water quality. The results indicated the dominance of the Ameki/Nanka Formation and Imo Formation as the underlying geology of the study area. The grain sizes of the sand samples ranged from medium to coarse grained, moderately to poorly sorted, and strongly positive to positively-skewed. The depositional environment was nearshore/beach, influenced by nearshore waves and turbulent currents. Engineering properties highlighted the prevalence of uniformly to well-graded soil and moderately to highly plastic behavior, as indicated by the mean plasticity index (PI) value of 26%. These findings suggest potential challenges for infrastructural development in some parts of the area. The water quality indicated slightly acidic water. The physical parameters and the major ions were within the permissible limits of World Health Organization (WHO) and the Nigerian Standard for Drinking Water Quality (NSDWQ). However, elevated concentrations of heavy metals, including lead, chromium, mercury, iron, and cadmium, in water sources exceeded the respective permissible limits for drinking water indicating contamination/pollution. The dominant water type was Ca2+ – Mg2+– SO42- – Cl– and the dominant hydrochemical process was simple dissolution or mixing and ion-exchange.

RNAi-chitosan biopesticides for managing forest insect pests: an outlook

The expanding world population demands superior forest protection to fulfil feasible environmental certainty. The persistent pest infestations negatively influence forest health and cause substantial economic losses. In contrast, the traditional use of conventional pesticides results in a loss of soil microbial biodiversity, a drop in the population of pollinators, and adverse effects on other non-target organisms, including humans. Global forestry is looking for solutions to reduce the adverse environmental effects of current chemical pesticides. RNAi-nanotechnology has recently drawn much attention for its use in pest management. The advantages of engineered RNAi-chitosan nano-formulations in terms of simple digestion and dissolution, non-toxicity, high adsorption power, potential biodegradation in nature, and widespread availability and cost-effectiveness, have been well documented for pest management in agroecosystems. However, deploying such control strategies in forest ecosystems is still pending and demands further research. Hence, we highlight the putative uses of RNAi-chitosan biopesticides and their preparation, characterization, and putative application methods for forest pest management. We also discussed potential environmental risks and plausible mitigation strategies.

Lignin-derived heteroatom-doped hierarchically porous carbon for high-performance supercapacitors: “Structure-function” relationships between lignin heterogeneity and carbon materials

Sustainably sourced lignin is a desired precursor for carbon materials due to its cross-clinked aromatic structure and high carbon content. However, the heterogeneity of lignin feedstock presents non-negligible effects on its physicochemical properties and thereby substantially influences its applications in carbon materials fabrication. In this work, fractionation of corn stalk enzymatic hydrolysis lignin via a simple two-step ordinal dissolution was adapted to reduce lignin heterogeneity and further improve the microstructure and electrochemical performances of lignin-derived heteroatom-doped carbon materials. The results revealed that the fractionation process successfully obtained three lignin fractions with sequentially increasing molecular weight and specific surface area. When the three lignin fractions were subjected to carbonization/activation to fabricate N/P/S co-doped carbon, the F3-derived carbon material (LC-F3) showed the highest specific surface area (2022.4 m2/g) and the best heteroatom doping effect due to the improved activation process resulted from the largest specific surface area of F3. Moreover, the good thermal stability of F3 also contributed to the maintenance of disordered structure during carbonization. Therefore, LC-F3 exhibited excellent specific capacitance (337.2 F/g, 0.5 A/g) and cycling stability (96.5% after 10,000 cycles) as a consequence of its high disordered level, heteroatom doping density and specific surface area. Consequently, this work systematically evaluates the effects of lignin fractionation on the physicochemical structural and electrochemical performances of the carbon materials and further proposes a simple strategy to enhance electrochemical properties of the heteroatom-doped carbon materials through lignin fractionation.

Combining in vitro dissolution/permeation with microdialysis sampling: Capabilities and limitations for biopharmaceutical assessments of supersaturating drug formulations

Many novel small drug molecules are poorly water-soluble and thus, enabling drug formulations may be required to ensure sufficient absorption upon oral administration. Biopharmaceutical assessment and absorption prediction of enabling formulations, however, remains challenging. Combined in vitro dissolution/permeation (D/P) assays have gained increasing interest since they may provide a more realistic formulation ranking based on the drug permeation profiles from different formulations as compared to conventional dissolution, which captures both readily permeable and not readily permeable fractions of “dissolved” drug. Moreover, the combined in vitro D/P assays allow to better predict intestinal supersaturation and precipitation processes as compared to simple dissolution setups due to the effect of an absorptive sink. Microdialysis on the other hand has proven useful to determine molecularly dissolved drug in colloidal dispersions, thus allowing for a deeper mechanistic insight into the mechanism of drug release from supersaturating formulations.Here, microdialysis sampling from the donor compartment was used in combination with the dissolution/permeation (D/P) tool PermeaLoop™ to study commercial supersaturating drug formulations of the poorly soluble and weakly basic drug Posaconazole (PCZ). An amorphous solid dispersion (ASD)-based tablet, as well as a crystalline suspension in acidified and neutral dilution medium, respectively, were tested. Microdialysis sampling allowed for differentiation between molecularly dissolved and micellar drug concentration, as expected, but, surprisingly, it was found that the presence of the microdialysis probe affected the precipitation behavior of a crystalline suspension within the two-stage D/P setup, simulating the oral administration of the acidified PCZ (Noxafil®) suspension: the extent and duration of supersaturation in the donor decreased significantly, which also affected permeation. Similarly, for the ASD-based tablet, a less pronounced supersaturation was observed during the first 120 min of the experiment. Hence, in this case, the formulation ranking and the prediction of intestinal supersaturation in the in vitro D/P assay became less predictive as compared to a conventional PermeaLoop™ study without microdialysis sampling. It was concluded that valuable mechanistic insights into the molecularly dissolved drug profiles over time can be obtained by microdialysis. However, since the presence of the probe may affect the degree of supersaturation and precipitation, a conventional D/P assay (without microdialysis sampling) is preferred for formulation ranking of supersaturating drug formulations.

Geochemical evaluation of groundwater around Chromepet tannery belt, Southern India

The study appraises the geogenic and anthropogenic contamination of groundwater around tanneries located in Chromepet, Southern India. Thirty-six groundwater samples were examined for major anions, cations and trace metals concentration. The concentration of chromium (Cr), iron (Fe) and lead (Pb) in the study area ranges from 0.04 to 0.51 mg/L, 0.001–1.07 mg/L and 0.001–0.09 mg/L respectively. 97% of the samples exceeded the acceptable range for Cr whereas, lead and iron exceeded 89 and 8% of the samples respectively. The high concentrations of chromium, iron and lead in the groundwater are due to the influence of tannery effluents. The majority of the samples in the study area suggested silicate weathering. The piper plot reveals that 50% of the water samples have Na–Cl type water which is possibly due to anthropogenic sources. The Chadha plot revealed that silicate weathering and ion exchange govern the bulk of groundwater chemistry in freshwater aquifers owing to carbonate precipitation and mineral dissolution. Durov plot highlights that the bulk of the samples has no dominating anion or cation types, indicating simple dissolution or mixing. Saturation Index (SI) reveals that 50% of the samples were supersaturated due to calcite and dolomite precipitation. Principal Component Analysis (PCA) 1 suggested secondary salt discharge from geogenic and anthropogenic processes due to tanning industries. Increasing the performance of wastewater treatment plants is essential to improve the groundwater quality of the region under tannery influence.

Determination of metals and metalloids in traces in honey: Evaluation of different sample preparation methods and assay techniques

Literature reports several protocols for assaying metals and metalloids in foodstuffs. This study aimed to identify the most effective combination of sample preparation methods and three atomic spectroscopy instruments for quantifying trace elements in honey. We show that instrumental LODs demonstrated that FAAS is not sensitive enough to control the most toxic elements in honey, at a level complying with European recommendations (e.g., 0.1 mg kg−1 for Pb). This technique should only be used to assay oligo-elements present at higher concentrations in honey such as Zn. The use of extraction methods for sample preparation protocols was excluded due to their incompatibility with the matrix (liquid-liquid extraction) or the low recovery rates achieved (e.g., 0% for As, 48% for Cd, or only 70% for Mn) with solid-phase extraction. The construction of simplified accuracy profiles objectively confirmed that the dilution factor, inherent to the sample preparation, is critical for the choice of the method, especially with ICP-OES measurements. Finally, calcination of the sample followed by an ICP-OES analysis or a simple dissolution in diluted hydrogen peroxide followed by GFAAS analysis were put forward and validated.

Anchoring Pt Particles onto Mesoporousized ZnO Holey Cubes for Triethylamine Detection with Multifaceted Superiorities.

Designing sensing materials with integrating unique spatial structures, functional units, and surface activity is vital to achieve high-performance gas sensor toward triethylamine (TEA) detection. Herein, a simple spontaneous dissolution is used with subsequent thermal decomposition strategy to fabricate mesoporousized ZnO holey cubes. The squaric acid is crucial to coordinate Zn2+ to form a cubic shape (ZnO-0) and then tailor the inner part to open a holey cube with simultaneously mesoporousizing the left cubic body (ZnO-72). To enhance the sensing performance, the mesoporous ZnO holey cubes have been functionalized with catalytic Pt nanoparticles, which deliver superior performances including high response, low detection limit, and fast response and recovery time. Notably, the response of Pt/ZnO-72 towards 200ppm TEA is up to 535, which is much higher than those of 43 and 224 for pristine ZnO-0 and ZnO-72. A synergistic mechanism combining the intrinsic merits of ZnO, its unique mesoporous holey cubic structure, the oxygen vacancies, and the catalytic sensitization effect of Pt has been proposed for the significant enhancement in TEA sensing. Ourwork provides an effective facile approach to fabricate an advanced micro-nano architecture with manipulating its spatial structure, functional units, and active mesoporous surface for promising TEA gas sensors.

Extraction of niclosamide from commercial approved tablets into aqueous buffered solution creates potentially approvable oral and nasal sprays against COVID-19 and other respiratory infections

MotivationThe low solubility, weak acid drug, niclosamide is a host cell modulator with broad-spectrum anti-viral cell-activity against many viruses, including stopping the SARS-CoV-2 virus from infecting cells in cell culture. As a result, a simple universal nasal spray preventative was proposed and investigated in earlier work regarding the dissolution of niclosamide into simple buffers. However, starting with pharmaceutical grade, niclosamide represents a new 505(b)(2) application. The motivation for this second paper in the series was therefore to explore if and to what extent niclosamide could be extracted from commercially available and regulatory-approved niclosamide oral tablets that could serve as a preventative nasal spray and an early treatment oral/throat spray, with possibly more expeditious testing and regulatory approval.ExperimentalMeasurements of supernatant niclosamide concentrations were made by calibrated UV-Vis for the dissolution of niclosamide from commercially available Yomesan crushed into a powder for dissolution into Tris Buffer (TB) solutions. Parameters tested were as follows: time (0–2 days), concentration (300 µM to -1 mM), pH (7.41 to 9.35), and anhydrous/hydrated state. Optical microscopy was used to view the morphologies of the initial crushed powder, and the dissolving and equilibrating undissolved excess particles to detect morphologic changes that might occur.ResultsConcentration dependence: Niclosamide was readily extracted from powdered Yomesan at pH 9.34 TB at starting Yomesan niclosamide equivalents concentrations of 300 µM, 600 µM, and 1 mM. Peak dissolved niclosamide supernatant concentrations of 264 µM, 216 µM, and 172 µM were achieved in 1 h, 1 h, and 3 h respectively. These peaks though were followed by a reduction in supernatant concentration to an average of 112.3 µM ± 28.4 µM after overnight stir on day 2. pH dependence: For nominal pHs of 7.41, 8.35, 8.85, and 9.35, peak niclosamide concentrations were 4 µM, 22.4 µM, 96.2 µM, and 215.8 µM, respectively. Similarly, the day 2 values all reduced to 3 µM, 12.9 µM, 35.1 µM, and 112.3 µM. A heat-treatment to 200 °C dehydrated the niclosamide and showed a high 3 h concentration (262 µM) and the least day-2 reduction (to 229 µM). This indicated that the presence, or formation during exposure to buffer, of lower solubility polymorphs was responsible for the reductions in total solubilities. These morphologic changes were confirmed by optical microscopy that showed initially featureless particulate-aggregates of niclosamide could grow multiple needle-shaped crystals and form needle masses, especially in the presence of Tris-buffered sodium chloride, where new red needles were rapidly made. Scale up: A scaled-up 1 L solution of niclosamide was made achieving 165 µM supernatant niclosamide in 3 h by dissolution of just one fifth (100 mg niclosamide) of a Yomesan tablet.ConclusionThese comprehensive results provide a guide as to how to utilize commercially available and approved tablets of niclosamide to generate aqueous niclosamide solutions from a simple dissolution protocol. As shown here, just one 4-tablet pack of Yomesan could readily make 165 L of a 20 µM niclosamide solution giving 16,500 10 mL bottles. One million bottles, from just 60 packs of Yomesan, would provide 100 million single spray doses for distribution to mitigate a host of respiratory infections as a universal preventative-nasal and early treatment oral/throat sprays throughout the world.Graphical pH dependence of niclosamide extraction from crushed Yomesan tablet material into Tris buffer (yellow-green in vial) and Tris-buffered saline solution (orange-red in vial). Initial anhydrous dissolution concentration is reduced by overnight stirring to likely monohydrate niclosamide; and is even lower if in TBSS forming new niclosamide sodium needle crystals grown from the original particles.

Pullulan Films with PCMs: Recyclable Bio-Based Films with Thermal Management Functionality

The use of phase-changing materials (PCMs) is a practical and powerful way of buffering thermal fluctuations and maintaining the isothermal nature of the storage process. In this study, melamine formaldehyde microcapsules with paraffin cores were used as PCMs; pullulan films with PCMs were prepared by the film-casting method; and the composite films prepared were analysed with regard to their chemical structure, thermal properties, thermal stability, and recyclability. Uniform films displaying thermal management functionality were prepared. The amount of 75 wt.% PCM were added to the pullulan film structure which enabled the preparation of a composite film that displayed 104.85 J g−1 of heat storage during heating and 103.58 J g−1 of heat release during cooling. Multiple heating and cooling cycles showed that the composite films maintained their thermal management functionality after multiple heating-cooling cycles. The PCMs could be recovered with a yield of approximately 95% by the application of a simple dissolution and filtration process. The morphology, chemical structure, and thermal properties of the PCMs were maintained after the recovery process. The bio-based composite films with thermal management functionality and recyclability are proposed as an innovative, practical, and effective system for thermoactive storage and packaging applications.

Dissolution Method development and validation for simultaneous determination of Metformin and Teneligliptin in pharmaceutical tablets

We have developed and validated an inexpensive, selective, simple, and precise HPLC-RP dissolution method for estimating the concentration of Metformin and Teneligliptin in combination dosage form. This experimental analysis was performed on a reverse phase high performance high-performance liquid chromatography, (RP-HPLC) column (250mm x 4.6mm, 5µm) by using Mobile phase Acetonitrile and Potassium Dihydrogen Phosphate with concentration 0.05 M and buffer with pH-7.0 at a flow rate of 1.0ml/min and the detected at wavelength 225nm. In line with ICH guidelines, the linearity of the analytical method was discovered to be in the range of 7.0 to 21.00g/ml for Metformin. The linearity of the method for Teneligliptin was 22.5-67.5g/ml. Metformin and Teneligliptin had correlation coefficients greater than 0.990. The relative standard deviation value for system precision and method was less than 2.0%. All statistical data proves validity of the method and can be used for routine analysis of pharmaceutical dosage form.

Geoquímica e processos hidroquímicos de águas subterrâneas no aquífero Egbako, Bacia de Bida do Norte, Nigéria

ABSTRACT Thirty-five groundwater samples from the aquifer were collected and analyzed for major cations and anions to understand the groundwater chemistry and hydrochemical processes in the Egbako aquifer. Laboratory studies identified the major ions while the results were analyzed using different graphical methods and ionic plots. The abundance of the major cations and anions are Ca2+&gt;K+&gt;Na+&gt;Mg2+ and HCO3-&gt;NO3-&gt;Cl-&gt;SO42- respectively. The dominant hydrochemical facies are calcium-bicarbonate (Ca-HCO3), sodium-bicarbonate (Na-HCO3) and mixed calcium-sodium bicarbonate (Ca-Na-HCO3) water types. Interpretation of bivariate and scatter plots indicate silicate weathering, simple dissolution and ion exchange as the dominant processes in the aquifer. Saturation indices reveals evaporites (halite, gypsum and anhydrite) undersaturation, supersaturation in most samples with respect to silicates (quartz and kaolinite) and few samples for carbonate (calcite, aragonite, dolomite). Assessment of the water quality indicate that they are chemically suitable for human consumption except in the agricultural fields of southwestern areas where high nitrate concentration is present.