Laser Diffraction Spectroscopy Research Articles

Droplet sizes and delivery rates from film breakup aerosolisation mode in porous materials

Abstract A novel two-phase aerosolisation mode utilizing porous materials is investigated, aiming to improve aerosol delivery for medical inhalation. Sintered stainless steel filters with varied pore sizes (PS) from 0.2 μm to 7 μm were used to generate aerosols from a 0.9 wt.% sodium chloride solution. Droplet sizes and delivery rates were measured using laser diffraction spectroscopy. Further measurements included shadow imaging. Results indicate that aerosolisation occurs within a specific range of PS with droplet sizes increasing with increasing PS. The droplets generated are suitable for inhalation therapies. A hypothesis is established about the process of droplet formation which states that different PS within the porous material serve distinct functions that contribute to the breakup of liquid films into aerosol particles. Droplet formation is the result of film breakup in pores filled with fluid. This low-energy aerosolisation method has the potential to be used in handheld devices for sensitive drug formulations, overcoming the limitations of current technologies. Further research is needed to optimize the pore size distribution and enhance aerosol generation efficiency.

Insights on Microplastic Contamination from Municipal and Textile Industry Effluents and Their Removal Using a Cellulose-Based Approach.

The rampant use of plastics, with the potential to degrade into insidious microplastics (MPs), poses a significant threat by contaminating aquatic environments. In the present study, we delved into the analysis of effluents from textile industries, a recognized major source of MPs contamination. Data were further discussed and compared with a municipal wastewater treatment plant (WWTP) effluent. All effluent samples were collected at the final stage of treatment in their respective WWTP. Laser diffraction spectroscopy was used to evaluate MP dimensions, while optical and fluorescence microscopies were used for morphology analysis and the identification of predominant plastic types, respectively. Electrophoresis was employed to unravel the prevalence of negative surface charge on these plastic microparticles. The analysis revealed that polyethylene terephthalate (PET) and polyamide were the dominant compounds in textile effluents, with PET being predominant in municipal WWTP effluents. Surprisingly, despite the municipal WWTP exhibiting higher efficiency in MP removal (ca. 71% compared to ca. 55% in textile industries), it contributed more to overall pollution. A novel bio-based flocculant, a cationic cellulose derivative derived from wood wastes, was developed as a proof-of-concept for MP flocculation. The novel derivatives were found to efficiently flocculate PET MPs, thus allowing their facile removal from aqueous media, and reducing the threat of MP contamination from effluents discharged from WWTPs.

A multi-nozzle nebuliser does not improve tissue drug delivery during PIPAC

BackgroundMulti-nozzle nebulisers for pressurised intraperitoneal aerosol chemotherapy (PIPAC) are implemented in clinical practice to improve the homogeneity of tissue drug delivery. Nonetheless, the advantages of such devices over one-nozzle nebulisers have not been demonstrated thus far. In this study, we compared the performance of multi- and one-nozzle nebulisers by conducting physical and ex vivo pharmacological experiments.MethodsThe one-nozzle nebuliser Capnopen® and the multi-nozzle nebuliser were the subjects of this study. In physical experiments, the aerosol droplet size was measured by laser diffraction spectroscopy. Spatial spray patterns were depicted on blotting paper. Pharmacological experiments were performed on the enhanced inverted bovine urinary bladder model, demonstrating real-time tissue drug delivery, aerosol sedimentation and homogeneity of doxorubicin and cisplatin tissue distribution.ResultsThe multi-nozzle nebuliser had a sixfold greater aerosolisation flow and a threefold greater angle of aerosolisation than Capnopen®. The aerosol particle size and distribution range were higher than that of Capnopen®. Spray patterns on blotting paper were more extensive with the multi-nozzle nebuliser. Real-time tissue drug delivery with the multi-nozzle nebuliser was over 100 ml within 1 min, and the aerosol sedimentation was 48.9% ± 21.2%, which was not significantly different from that of Capnopen®. The doxorubicin and cisplatin tissue concentrations were greater with Capnopen®. Although there was no significant difference in the homogeneity of doxorubicin distribution between the two devices, the homogeneity of cisplatin distribution was significantly higher with Capnopen®.ConclusionThe multi-nozzle PIPAC nebuliser did not fulfil expectations. Even though the surface spray patterns were broader with the multi-nozzle nebuliser, the tissue drug homogeneity and concentration were greater with Capnopen®.Graphical

Closer Approach towards the Preparation of Cellulose and Microcrystalline Cellulose from Corn Husks

AbstractIn this work, cellulose was effectively produced from corn husks by a simple and eco‐friendly method. Major influencing variables for cellulose extraction were examined, and the highest yield of lignin and hemicellulose cleavage was achieved after corn husks were treated in 12.5 wt % NaOH solution at solid/liquid ratio (S/L) of 1:10 g mL−1, 70 °C for 90 min. Subsequent bleaching conducted in 10 wt % H2O2 solution at 80 °C for 90 min produced cellulose with a lightness value (L*) of ∼87, chromaticity indexes a* = −1.85, b* = 2.94 with high purity, 90.86 %, and crystallinity, 64.94 %. Fourier transform infrared, scanning electron microscopy, and x‐ray diffraction analysis showed a clear transition in morphology, structure modification, and crystallinity consistent with the alteration of the chemical composition from raw material to delignified residue and the bleached one. To synthesize microcrystalline cellulose (MCC), the hydrolysis was investigated in H2SO4 solutions of different concentrations and durations via monitoring particle size distribution by laser diffraction spectroscopy. At the most efficient conditions (30 wt % H2SO4, 18 h, 45 °C, 1:10 S/L ratio), the obtained MCC reached an average particle size of 42.68 µm, crystallinity degree of 61.6 %, and cellulose purity of 92.5 %. Meanwhile, similar parameters with 4 N HCl solution produced MCC with the same purity but higher crystallinity (65.6 %), higher mean size, 67.62 µm, and higher aspect ratio. SEM images showed that 4 N HCl caused less detrimental and erosive action, and less fragmentation on cellulose microfibrils compared to 30 wt % H2SO4. The study's outcome supports the feasibility of corn husks to produce cellulose and MCC for further applications.

Laser sintering of polyamide 12 with limited thermal degradation

The paper presents, for the first time, the results of PA12 polyamide sintering using the original method of Dual Beam Laser Sintering of polymers (DBLS). The DBLS method, which is a modification of the standard polymer Laser Sintering (pLS) approach, allows to reduce the thermal degradation of the polymer by using selective (in terms of powder volume and process time) heating the material with laser radiation. The paper presents both the properties of sintered parts and the analysis of the degree of thermal degradation of post-process powders. Examination of the sintered parts included X-ray computed tomography (XCT) to visualize and analyze their porosity and a tensile test. Post-process powders were evaluated by Gel Permeation Chromatography (GPC), Melt Flow Rate (MFR), Dry Laser Diffraction Spectroscopy (DLD) and Powder Rheometer (FT4). The analysis of the result of PA12 sintering with the DBLS method was carried out in comparison with the classic pLS approach. As it has been shown, the DBLS approach allows to obtain comparable results for sintered parts compared to the pLS method. What is particularly important, it was shown that the post-process powder in the DBLS method has almost unchanged properties - the change in molecular weight and viscosity is at the level of the measurement error. Reducing thermal degradation is especially important in order to obtain continuous circulation of the powder in the manufacturing process.

Performance of different nebulizers in clinical use for Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC).

Technical ex-vivo comparison of commercial nebulizer nozzles used for Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC). The performance of four different commercial nebulizer nozzles (Nebulizer; HurriChemTM; MCR-4 TOPOL®; QuattroJet) was analysed concerning: i) technical design and principle of operation, ii) operational pressure as function of the liquid flow rate, iii) droplet size distribution via laser diffraction spectrometry, iv) spray cone angle, spray cone form as well as horizontal drug deposition by image-metric analyses and v) chemical resistance via exposing to a cytostatic solution and chemical composition by means of spark optical emission spectral analysis. The Nebulizer shows quasi an identical technical design and thus also a similar performance (e.g., mass median droplet size of 29 μm) as the original PIPAC nozzles (MIP/ CapnoPen). All other nozzles show more or less a performance deviation to the original PIPAC nozzles. The HurriChemTM has a similar design and principle of operation as the Nebulizer, but provides a finer aerosol (22 μm). The principle of operation of MCR-4 TOPOL® and QuattroJet differ significantly from that of the original PIPAC nozzle technology. The MCR-4 TOPOL® offers a hollow spray cone with significantly larger droplets (50 μm) than the original PIPAC nozzles. The QuattroJet generates an aerosol (22 μm) similar to that of the HurriChemTM but with improved spatial drug distribution. The availability of new PIPAC nozzles is encouraging but can also have a negative impact if their performance and efficacy is unknown. It is recommended that PIPAC nozzles that deviate from the current standard should be subject to bioequivalence testing and implementation in accordance with the IDEAL-D framework prior to routine clinical use.

Microorganisms Isolated from Saharan Dust Intrusions in the Canary Islands and Processes of Mineral Atmospherogenesis

Global warming due to climate change has increased the frequency of sand and dust storms that affect air quality and ecosystems in general, contributing to air pollution. The Sahara Desert is the most potent emitter of atmospheric dust. The atmosphere is an extreme environment and microorganisms living in the troposphere are exposed to greater ultraviolet radiation, desiccation, low temperatures and nutrient deprivation than in other habitats. The Iberian Peninsula, and specifically the Canary Islands—due to its strategic location—is one of the regions that receive more Saharan dust particles annually, increasing year after year, although culturable microorganisms had previously never been described. In the present work, dust samples were collected from three calima events in the Canary Islands between 2021 and 2022. The sizes, mineralogical compositions and chemical compositions of dust particles were determined by laser diffraction, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. Particle morphology and biological features were also studied by scanning electron microscopy (SEM-EDX) and confocal laser scanning microscopy (CLSM). The mineral–bacteria interactions were described from microscopic observations, which revealed the presence of iberulites and small neoformed kaolinite crystals in association with bacteria. This article defines the term “mineral atmospherogenesis” and its variant, “mineral bioatmospherogenesis”, through microbial interaction. This is the first described case of kaolinite produced through mineral bioatmospherogenesis. The bacterial growth in atmospheric dust was illustrated in SEM images, constituting a novel finding. Twenty-three culturable microorganisms were isolated and identified by 16S rRNA sequencing. Members of the phyla Pseudomonadota, Bacillota and Actinomycetota have been found. Some of these microorganisms, such as Peribacillus frigoritolerans, have Plant Growth-Promoting Rhizobacteria (PGPR) properties. Potential human pathogenic bacteria such as Acinetobacter lwoffii were also found. The presence of desert dust and iberulites in the Canary Islands, together with transported biological components such as bacteria, could have a significant impact on the ecosystem and human health.

Synergistic effect of CaCu3Ti4O12 ceramic and Ti3C2Tx MXene nanoflakes on the dielectric properties of poly (vinylidene fluoride) composites

Polymer composites are popular multifunctional materials. Their effective use in elements of electronic devices is possible due to the optimal dielectric properties. In this work, a balance between a high dielectric constant and a low dielectric loss tangent was achieved by introducing two types of fillers into poly (vinylidene fluoride): ceramic CaCu3Ti4O12 (10, 20 and 30 vol%) and conductive Ti3C2Tx MXene (2.5–5 wt%). CCTO ceramics was synthesized by the solid-state method. Ti3C2Tx MXene was obtained by etching the Al layer from Ti3AlC2 MAX phase under hydrothermal conditions. The materials were studied by XRD, SEM, FTIR, laser diffraction, and impedance spectroscopy. Composites based on poly (vinylidene fluoride) with 30 vol% CaCu3Ti4O12 and 5 wt% Ti3C2Tx MXene demonstrated the most promising results when increasing the dielectric constant to 28 at a dielectric loss tangent value of 0.061 at a frequency of 10 kHz. At the same time, the electrical strength of the composites had values not lower than 100 MV∙m−1, which is extremely important for their practical application. The results obtained can be used in the development of modern polymer composite dielectrics for passive elements of flexible electronics.

Oral Delivery of Insulin from Trimethyl Chitosan/Tragacanth: In Vitro, MTT, and In Vivo Bioactivity Tests

: Insulin-loaded Trimethyl Chitosan (TMC)/tragacanth microspheres were prepared by microemulsion dispersion and triggered in situ gelation. Microspheres were characterized by their mean size and distribution by laser diffraction spectroscopy and Brunauer-Emmet-Teller theory. Insulin encapsulation efficiency and in vitro release were determined by Bradford protein assay, and bioactivity was assessed in vitro using an enzyme-linked immunoassay diagnostic kit and in vivo using Wistar diabetic rats. TMC/tragacanth particles suppressed insulin release in acidic media and promoted a sustained release at near-neutral conditions. Micro-capsulated insulin was bioactive, demonstrated by both in vivo and in vitro bioassays.

Improved in vitro biocompatibility and cytoplasmic localization of gold nanoparticles and graphene oxide nanosheets assessed using confocal microscopy

Nanomaterial-based delivery platforms have indeed revolutionized drug delivery systems in recent years. These platforms, which are based on various types of nanoparticles, offer several advantages over traditional drug delivery systems. Therefore, during this work, we synthesized gold nanoparticles (GNPs) and graphene oxide (GO) as representative nanomaterials and assessed their biocompatibility and cytoplasmic localization in vitro. Structural characterization of the prepared nanoparticles was performed by using different techniques. For instance, laser diffraction spectrometry using a Nano-ZS Zetasizer was used to determine the particles size, and Zeta potential. High-resolution transmission electron microscopy (HR-TEM) were utilized to evaluate Particle sizes and morphologies of the prepared nanoparticles. Additionally, the chemical structure of the prepared nanoparticles was assessed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The effects of the different concentrations of GNPs and GO nanosheets on cell viability and proliferation were evaluated by WST-1 cell proliferation assays. Ultimately, in vitro studies were performed by confocal microscopy to characterize the cellular uptake of the prepared nanoparticles. The net results of this study suggest that both nanomaterials showed a cytoplasmic entry without penetrating the nucleus. They may be useful for slow drug release as well as photothermal and photodynamic therapy using a low-powered laser or IR radiation.

Controlling lipid crystallization across multiple length scales by directed shear flow.

The crystallization behavior of lipids is relevant in many fields such as adipose tissue formation and regeneration, forensic investigations and food production. Using a lipid model system composed of triacylglycerols, we study the formation of crystalline structures under laminar shear flows across various length scales by polarized light-, scanning electron-, and atomic force microscopy, as well as laser diffraction spectroscopy. The shear rate during crystallization γ̇cryst influences the acyl-chain length structure and promotes domain growth into the flow direction thereby transforming the crystallites from oblate into prolate particles. Concentration dependent aggregation of crystallites into clusters is the rate limiting step for floc and floc network formation. At high γ̇cryst, fast crystallite cluster formation at smaller equilibrium diameters is promoted. The high crystallite cluster concentration induces their aggregation into flocs which form weak networks. At low γ̇cryst, floc generation is limited by the low amount of crystallite clusters leading to slow growth of larger flocs and forming of strong networks. The findings in this work have potential implications ranging from the design of injectable soft tissue fillers for adipose tissue regeneration, to the crystalline network formation in microorganism derived lipids, up to a more energy-efficient production of chocolate confectionery.

Feasibility of pressurized intra peritoneal aerosol chemotherapy using an ultrasound aerosol generator (usPIPAC)

BackgroundWe tested the feasibility of ultrasound technology for generating pressurized intraperitoneal aerosol chemotherapy (usPIPAC) and compared its performance vs. comparator (PIPAC).Material and methodsA piezoelectric ultrasound aerosolizer (NextGen, Sinaptec) was compared with the available technology (Capnopen, Capnomed). Granulometry was measured for water, Glc 5%, and silicone oil using laser diffraction spectrometry. Two- and three-dimensional (2D and 3D) spraying patterns were determined with methylene blue. Tissue penetration of doxorubicin (DOX) was measured by fluorescence microscopy in the enhanced inverted Bovine Urinary Bladder model (eIBUB). Tissue DOX concentration was measured by high-performance liquid chromatography (HPLC).ResultsThe droplets median aerodynamic diameter was (usPIPAC vs. PIPAC): H20: 40.4 (CI 10–90%: 19.0–102.3) vs. 34.8 (22.8–52.7) µm; Glc 5%: 52.8 (22.2–132.1) vs. 39.0 (23.7–65.2) µm; Silicone oil: 178.7 (55.7–501.8) vs. 43.0 (20.2–78.5) µm. 2D and 3D blue ink distribution pattern of usPIPAC was largely equivalent with PIPAC, as was DOX tissue concentration (usPIPAC: 0.65 (CI 5-95%: 0.44–0.86) vs. PIPAC: 0.88 (0.59–1.17) ng/ml, p = 0.29). DOX tissue penetration with usPIPAC was inferior to PIPAC: usPIPAC: 60.1 (CI 5.95%: 58.8–61.5) µm vs. PIPAC: 1172 (1157–1198) µm, p < 0.001). The homogeneity of spatial distribution (top, middle and bottom of the eIBUB) was comparable between modalities.DiscussionusPIPAC is feasible, but its performance as a drug delivery system remains currently inferior to PIPAC, in particular for lipophilic solutions.

Experimental Study on the Transport and Alteration Behavior of Aerosols From Low Density Powders for Acute Inhalation Toxicology Studies.

Low density powders have a bulk density of less than 100 kg/m3 and are produced technically by flame pyrolysis of silicon tetrachloride (pyrogenic powders such as pyrogenic silica) or wet-chemically by sol-gel processes (e.g. silica-gel) or precipitation reactions using sodium silicate solution and a mineral acid. The transport and alteration behavior of aerosols from low density powders was investigated in a device for toxicological inhalation studies. The test conditions corresponded to those for acute toxicology studies according to OECD Guideline 436. The use of cascade impactors, required by guideline, has not proven successful for low density powders as the fragile agglomerate structures are destroyed during the measurement. As an alternative and non-invasive measurement method, laser diffraction spectroscopy has proved very successful in the present investigations. In particular, aerosols from pyrogenic powders of low density showed a distinctive tendency to re-agglomerate, especially at concentrations >500 mg/m3mm3. Investigation results indicate that aerosol particle size must be monitored over the entire acute inhalation test period for acute inhalation studies to be performed reliably.

Development and technical validation of an ultrasound nebulizer to deliver intraperitoneal pressurized aerosols in a rat colon cancer peritoneal metastases model

Background/aimTo develop and validate a nebulizer device for anti-cancer research on pressurized intraperitoneal aerosol supply in a preclinical peritoneal metastases (PM) rat model.Material and methodsFor aerosol generation, an ultrasonic nebulizer (USN) was modified. Aerosol analyses were performed ex-vivo by laser diffraction spectrometry (LDS). Intraperitoneal (IP) 99mtechnetium sodium pertechnetate (99mTc) aerosol distribution and deposition were quantified by in-vivo single photon emission computed tomography (SPECT/CT) and compared to liquid IP instillation of equivalent volume/doses of 99mTc with and without capnoperitoneum. PM was induced by IP injection of HCT116-Luc2 human colon cancer cells in immunosuppressed RNU rats. Tumor growth was monitored by bioluminescence imaging (BLI), 18F-FDG positron emission tomography (PET) and tissues examination at necropsy.ResultsThe USN was able to establish a stable and reproducible capnoperitoneum at a pressure of 8 to 10 mmHg. LDS showed that the USN provides a polydisperse and monomodal aerosol with a volume-weighted diameter of 2.6 μm. At a CO2 flow rate of 2 L/min with an IP residence time of 3.9 s, the highest drug deposition efficiency was found to be 15 wt.-%. In comparison to liquid instillation, nebulization showed the most homogeneous IP spatial drug deposition. Compared to BLI, 18F-FDG-PET was more sensitive to detect smaller PM nodules measuring only 1–2 mm in diameter. BLI, 18F-FDG PET and necropsy analyses showed relevant PM in all animals.ConclusionsThe USN together with the PM rat model are suitable for robust and species-specific preclinical pharmacological studies regarding intraperitoneal delivery of pressurized aerosolized drugs and cancer research.

Effect of Using Different Chemical Dispersing Agents in Grain Size Analyses of Fluvial Sediments via Laser Diffraction Spectrometry.

Laser diffraction spectrometry allows for efficiently obtaining high-resolution grain size data. However, pretreatment and dispersion of aggregates in sediment samples are essential pre-requisites for acquiring accurate results using this method. This study evaluates the effectiveness of five dispersing agents in deflocculating the investigated fluvial sediments and the resulting grain size distribution obtained by laser diffraction spectrometry. We also examine the ability of the different dispersing agents to deflocculate sediment samples treated by thermal combustion. Distilled water presented a low efficiency in deflocculating the samples and yielded a near-zero clay content for samples with an expected clay content. The other chemical dispersants were effective in dispersing aggregates and yielding clay, albeit with different efficiencies. Calgon had the highest dispersing ability, followed closely by sodium tripolyphosphate. The performance of chemical treatment with sodium oxalate approaches that of sodium tripolyphosphate. However, it leads to the formation of precipitates in the samples, obscuring the actual grain size data. Sodium pyrophosphate derived the least amount of deflocculation among the four chemical dispersants. Furthermore, all the chemical dispersants were found to be ineffective in dispersing aggregates in samples treated by thermal combustion.

Effect of carrier type and Tween® 80 concentration on the release of silymarin from amorphous solid dispersions

Silymarin is a mixture of flavonolignans obtained from the seeds of milk thistle (Silybum marianum L. Gaertner). Silymarin behaves as a weak acid and is categorised as a class IV drug substance in accordance with biopharmaceutics drug disposition classification system, possessing low solubility, as well as low bioavailability. The scope of this study was to identify possible formulation strategies of silymarin. Then, the main aim was to manufacture silymarin solid dispersions using a solvent evaporation approach and to characterise the physicochemical and drug release properties of the two formulations containing two different porous carriers, namely Avicel® PH-102 and Syloid® XDP 3150, and different concentrations of Tween® 80. Silymarin Log P was determined to be 1.6 (±0.14) negating the possibility of bypassing first pass metabolism via lymphatic transport. Utilising alkaline titration, the apparent pKa of silymarin was found to be similar to that of the silybin pKa (5.68). The crystallinity of raw silymarin was confirmed using powder X-ray diffraction and differential scanning calorimetry, and its thermal degradation was observed at a temperature higher than 220 °C (thermogravimetric analysis). Avicel® PH-102 and Syloid® XDP 3150 were characterised in terms of morphology using scanning electron microscopy, particle size distribution (laser diffraction spectroscopy), pore size distribution and intra-particle porosity using mercury intrusion porosimetry. Solid dispersions were manufactured using an organic solvent method incorporating silymarin, the carrier and optionally Tween® 80. The amorphous state of silymarin in all prepared formulations was confirmed using differential scanning calorimetry and powder X-ray diffraction. Silymarin dissolution kinetics were faster for Syloid® XDP 3150 versus Avicel® PH-102 and explained through carrier properties. The addition of Tween® 80 and increasing the concentration from 0.3 to 1.6% (w/w) significantly increased the drug release kinetics of Avicel® PH-102 formulations but had no effect on Syloid® XDP 3150 formulations. Drug release from prepared formulations was compared with Legalon® 70 using the similarity factor (F2). Syloid® XDP 3150-based formulations showed F2>50%. Tween® 80 had a negligible effect on the silymarin release from Syloid® XDP 3150-based formulations. Interestingly, the ability of Tween® 80 to inhibit gut wall efflux is well known. Thus, the inclusion of this excipient offers an opportunity to modulate the silymarin bioavailability without changing the drug release profile. A six-month stability study (at room temperature and 40% RH) confirmed that solid dispersions were still powder X-ray diffraction and differential scanning calorimetry amorphous. Acetone was used for both silymarin extraction and preparation of solid dispersions. Thus, there is an opportunity to use a single step to both load silymarin and form solid dispersions within a single-step.

Evaluation of Poorly Soluble Drugs' Dissolution Rate by Laser Scattering in Different Water Isotopologues.

The most important task in the design of dosage forms is to modify the pharmaceutical substances structure in order to increase solubilization, targeted delivery, controlled rate of drug administration, and its bioavailability. Screening—laboratory (in vitro) or computer (in silico)—as a procedure for selecting a prototype for the design of a drug molecule, involves several years of research and significant costs. Among a large number of solvents and diluents (alcohol, ether, oils, glycerol, Vaseline) used in the pharmaceutical industry for the manufacture of drugs water finds the greatest application. This is because all biological reactions (reactions in living systems) take place in water and distribution of the fluid in the body and the substances found within is critical for the maintenance of intracellular and extracellular functions. Modern studies in the field of the stable isotopic compositions of natural water and its structure and properties make it possible to use isotopic transformations of the water to improve the pharmacokinetic properties of medicinal substances without previous structural modification. It is known that by replacing any of the atoms in the reacting substance molecule with its isotope, it is possible to record changes in the reactivity, which are expressed as a change in the reaction rate constant, i.e., in the manifestation of the kinetic isotope effect (KIE). The article presents the results of studies on the effect of the kinetic isotope effect of a solvent—water—on increasing the solubility and dissolution rate constants of poorly soluble drugs using laser diffraction spectroscopy. The results of the studies can be successfully implemented in pharmaceutical practice to overcome the poor solubility of medicinal substances of classes II and IV, according to the biopharmaceutical classification system (BCS), in water for pharmaceutical purposes by performing its preliminary and safe isotopic modification.

Establishment of a Mouse Ovarian Cancer and Peritoneal Metastasis Model to Study Intraperitoneal Chemotherapy

Simple SummaryIntraperitoneal chemotherapy (IPC) is a locoregional treatment option in patients with peritoneal metastases (PM). Small animal models are valuable research tools allowing for rapid, reproducible, and inexpensive study and optimization of different forms of IPC. Here, we present a mouse model of ovarian cancer-derived PM and demonstrate its suitability for various modes of IPC, including pressurized intraperitoneal chemotherapy (PIPAC) using a micro-nozzle for aerosolized drug delivery.Intraperitoneal chemotherapy (IPC) is a locoregional treatment option in patients with peritoneal metastases (PM). Here, we present an ovarian cancer (OC)-derived PM mouse model for the study of different forms of IPC. Xenograft cell proliferation (luciferase-transfected OVCAR3 and SKOV3 clones) and growth kinetics were assessed using PET scan, bioluminescence imaging (BLI), and histological tumor analysis. Liquid IPC was achieved by intraperitoneal injection with/without capnoperitoneum (6–7 mmHg). Pressurized intraperitoneal aerosol chemotherapy (PIPAC) was mimicked using an intratracheal drug aerosol administration system (micro-nozzle), which, as demonstrated by ex vivo granulometric analysis using laser diffraction spectrometry, produced a polydisperse, bimodal aerosol with a volume-weighted median diameter of (26.49 ± 2.76) µm. Distribution of Tc-99m-labeled doxorubicin in mice was characterized using SPECT and was dependent on the delivery mode and most homogeneous when the micro-nozzle was used. A total of 2 mg doxorubicin per kg body weight was determined to be the optimally effective and tolerable dose to achieve at least 50% tumor reduction. Repeated PIPAC (four times at seven-day-intervals) with doxorubicin in SKOV3-luc tumor-bearing mice resulted in halted tumor proliferation and tumor load reduced after the second round of PIPAC versus controls and the number of tumor nodules was significantly reduced (27.7 ± 9.5 vs. 57.3 ± 9.5; p = 0.0003). Thus, we established the first mouse model of OC PM for the study of IPC using a human xenograft with SKOV3 cells and an experimental IPC setup with a miniaturized nozzle. Repeated IPC was feasible and demonstrated time-dependent anti-tumor activity.

Optimizing a standard preparation procedure for grain size analysis of marine sediments by laser diffraction (MS-PT4SD: Marine sediments-pretreatment for size distribution)

Grain size distributions are a key physical measurement in marine sediment studies. The introduction of laser diffraction spectrometry analyzers a few decades ago, allowed the differentiating of grain size in higher resolution than before, and led to increased volumes of samples analyzed overall. However, pretreatment of the sediment samples is required for obtaining high quality results by this method. Currently there are different pretreatment methods for different sediments, but no inclusive, standard method that is applicable across many types. Moreover, often the particulars of the methods are not fully described in the literature. A standard simple and effective pretreatment method which is applicable for a large variety of marine sediments is required as it can allow for intra and inter study comparisons. This study systematically tested and compared commonly applied digestion and dispersion pretreatment techniques for particle size analysis by laser diffraction spectrometry. The pretreatments were applied on a wide spectrum of marine sediments to distill a single protocol that produces precise, reliable, and consistent results across all samples. The recommended marine sediment pretreatment protocol (‘PT4SD’) reduces the needed amount of sediment for analysis, reduces handler bias and overall digestion time. We propose that using ‘PT4SD’ as a standard pretreatment protocol will greatly benefit sedimentological laboratories individually, as well as encourage and improve the depth of cross-study comparability, thereby improving the collective field of marine sedimentology and related research as a whole.

Development of fluorine-free waterborne textile finishing agents for anti-stain and solvent-water separation based on low surface energy (co)polymers

Fabric functionalization to obtain omniphobic textiles is an increasing trend due to science and technology push in our current society. Fluorochemicals dominate the water and oil-repellent textile finishing market because of their excellent performance. However, fluorinated chemicals release harmful substances giving rise to serious damage to ecosystems worldwide. In this paper, a series of fluorine-free, low surface energy and partially bio-based (co)polymethacrylates based on 3-[Tris(trimethylsilyloxy)silyl]propyl methacrylate (M3T) and stearyl methacrylate (SMA) have been successfully synthesized and characterized by Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and Energy-Dispersive X-ray Spectroscopy (EDS). Moreover, the particle size, particle size distribution and stability of developed emulsions have been assessed by laser diffraction spectrometry (LDS) and Z-potential measurements. The fluorine-free M3T/SMA (co)polymethacrylates have been applied on cotton fabrics by padding at several product dosages and coated textiles have been characterized by scanning electron microscopy (SEM), EDS element mapping, X ray fluorescence (XRF) and water and olive oil static contact angle measurements, WCA and OCA, respectively. Finally, performance of the fabrics treated with the new M3T/SMA (co)polymethacrylates has been evaluated and compared with textiles finished with conventional fluorinated chemicals. All the synthetized (co)polymethacrylates provide the coated substrates with high static water contact angles as well as excellent solvent-water separation efficiencies. However, only the textiles coated with the (co)polymethacrylates with higher M3T contents showed good repellence to olive oil, being able to keep the drop of oil on the surface for longer times. This time-dependent olive oil’s wettability observed for the copolymers with low contents on M3T units may be ascribed to: i) the evolution with time of the surface free energy of the coatings due to a reorientation over time of stearyl side chains of SMA during contact with the olive oil; and ii) the reduced barrier properties of the coatings with lower content of the bulky tris(trimethylsilyloxy)silyl side chains.