Tuning the Physical State of Aripiprazole by Mesoporous Silica.

The main purpose of our studies is to demonstrate that commercially available mesoporous silica (MS) can be used to control the physical state of aripiprazole (ARP). The investigations performed utilizing differential scanning calorimetry and broadband dielectric spectroscopy reveal that silica can play different roles depending on its concentration in the system with amorphous ARP. At low MS content, it activates recrystallization of the active pharmaceutical ingredient and supports forming the III polymorphic form of ARP. At intermediate MS content (between ca. 27 and 65 wt %), MS works as a recrystallization inhibitor of ARP. At these concentrations, the formation of III polymorphic form is no longer favorable; therefore, it is possible to use this additive to obtain ARP in either IV or X polymorphic form. At the same time, employing MS in concentrations >65 wt % amorphous form of ARP with high physical stability can be obtained. Finally, regardless of the polymorphic form it crystallizes into, each composite is characterized by the same temperature dependence of relaxation times in the supercooled and glassy states.

Spatially Formed Tenacious Nickel-Supported Bimetallic Catalysts for CO2 Methanation under Conventional and Induction Heating.

The paper introduces spatially stable Ni-supported bimetallic catalysts for CO2 methanation. The catalysts are a combination of sintered nickel mesh or wool fibers and nanometal particles, such as Au, Pd, Re, or Ru. The preparation involves the nickel wool or mesh forming and sintering into a stable shape and then impregnating them with metal nanoparticles generated by a silica matrix digestion method. This procedure can be scaled up for commercial use. The catalyst candidates were analyzed using SEM, XRD, and EDXRF and tested in a fixed-bed flow reactor. The best results were obtained with the Ru/Ni-wool combination, which yields nearly 100% conversion at 248 °C, with the onset of reaction at 186 °C. When we tested this catalyst under inductive heating, the highest conversion was observed already at 194 °C.

Identification of Sildenafil Compound in Selected Drugs Using X-ray Study and Thermal Analysis.

Twelve drugs containing sildenafil compounds (sildenafil citrate and sildenafil base) were examined using X-ray studies and thermal analysis. According to the manufacturer's information, the presence of sildenafil was confirmed in all investigated drugs. The positions of diffraction lines (value of 2θ angle) agree with the patterns presented in the ICDD database, Release 2018 (ICDD-International Centre of Diffraction Data). The difference expresses the agreement in the position of the diffraction line between the tested substance and the standard. A good agreement is when this difference is less than 0.2°. The values of interplanar distances dhkl are also compatible with the ICDD database. It indicated that the drug examined was genuine. Because all drugs are mixtures of different substances (API and excipients), the various diffraction line intensities were detected in all observed X-ray images for the tested drugs. The intensity of the diffraction line depends on many factors, like the amount of substance, coexisting phases, and mass absorption coefficient of the mixture. The thermal analysis confirmed the results obtained by the X-ray study. On DSC curves, the endothermic peaks for sildenafil compounds were observed. The determined melting points of sildenafil compounds corresponded to the values available in the literature. The results gathered by connecting two methods, X-ray study and thermal analysis, can help identify irregularities that may exist in pharmaceutical specimens, e.g., distinguishing genuine from counterfeit products, the presence of a correct polymorph, a lack of active substance, an inaccurate amount of the active substance, or excipients in the tested drug.

Influence of Dissolving Fe-Nb-B-Dy Alloys in Zirconium on Phase Structure, Microstructure and Magnetic Properties.

This paper refers to the structural and magnetic properties of [(Fe80Nb6B14)0.88Dy0.12]1-xZrx (x = 0; 0.01; 0.02; 0.05; 0.1; 0.2; 0.3; 0.5) alloys obtained by the vacuum mold suction casting method. The analysis of the phase contribution indicated a change in the compositions of the alloys. For x < 0.05, occurrence of the dominant Dy2Fe14B phase was observed, while a further increase in the Zr content led to the increasing contribution of the Fe-Zr compounds and, simultaneously, separation of crystalline Dy. The dilution of (Fe80Nb6B14)0.88Dy0.12 in Zr strongly influenced the magnetization processes of the examined alloys. Generally, with the increasing x parameter, we observed a decrease in coercivity; however, the unexpected increase in magnetic saturation and remanence for x = 0.2 and x = 0.3 was shown and discussed.

The Usefulness of X-ray Diffraction and Thermal Analysis to Study Dietary Supplements Containing Iron.

X-ray powder diffraction (XRPD) and thermal analysis (differential scanning calorimetry/derivative of thermogravimetry (DSC/DTG)) are solid-state techniques that can be successfully used to identify and quantify various chemical compounds in polycrystalline mixtures, such as dietary supplements or drugs. In this work, 31 dietary supplements available on the Polish market that contain iron compounds, namely iron gluconate, fumarate, bisglycinate, citrate and pyrophosphate, were evaluated. The aim of the work was to identify iron compounds declared by the manufacturer as food supplements and to try to verify compliance with the manufacturer's claims. Studies performed by X-ray and thermal analysis confirmed that crystalline iron compounds (iron (II) gluconate, iron (II) fumarate), declared by the manufacturers, were present in the investigated dietary supplements. Iron (II) bisglycinate proved to be semi-crystalline. However, depending on the composition of the formulation, it was possible to identify this compound in the tested supplements. For amorphous iron compounds (iron (III) citrate and iron (III) pyrophosphate), the diffraction pattern does not have characteristic diffraction lines. Food supplements containing crystalline iron compounds have a melting point close to the melting point of pure iron compounds. The presence of excipients was found to affect the shapes and positions of the endothermic peaks significantly. Widening of endothermic peaks and changes in their position were observed, as well as exothermic peaks indicating crystallization of amorphous compounds. Weight loss was determined for all dietary supplements tested. Analysis of the DTG curves showed that the thermal decomposition of most food supplements takes place in several steps. The results obtained by a combination of both simple, relatively fast and reliable XRPD and DSC/DTG methods are helpful in determining phase composition, pharmaceutical abnormalities or by detecting the presence of the correct polymorphic form.

X-ray and Thermal Analysis of Selected Drugs Containing Acetaminophen.

Studies carried out by X-ray and thermal analysis confirmed that acetaminophen (paracetamol), declared by the manufacturers as an Active Pharmaceutical Ingredient (API), was present in all studied medicinal drugs. Positions of diffraction lines (2θ angles) of the studied drugs were consistent with standards for acetaminophen, available in the ICDD PDF database Release 2008. |Δ2θ| values were lower than 0.2°, confirming the authenticity of the studied drugs. Also, the values of interplanar distances dhkl for the examined samples were consistent with those present in the ICDD. Presence of acetaminophen crystalising in the monoclinic system (form I) was confirmed. Various line intensities for API were observed in the obtained diffraction patterns, indicating presence of the preferred orientation of the crystallites in the examined samples. Thermal analysis of the studied substances confirmed the results obtained by X-ray analysis. Drugs containing only acetaminophen as an API have melting point close to that of pure acetaminophen. It was found that presence of other active and auxiliary substances affected the shapes and positions of endothermal peaks significantly. A broadening of endothermal peaks and their shift towards lower temperatures were observed accompanying an increase in the contents of additional substances being "impurities" in relation to the API. The results obtained by a combination of the two methods, X-ray powder diffraction (XRPD) and differential scanning calorimetry/thermogravimetry (DSC/TGA), may be useful in determination of abnormalities which can occur in pharmaceutical preparations, e.g., for distinguishing original drugs and forged products, detection of the presence of a proper polymorphic form or too low content of the active substance in the investigated drug.

A Study of Catalytic Oxidation of a Library of C2 to C4 Alcohols in the Presence of Nanogold.

The classical stoichiometric oxidation of alcohols is an important tool in contemporary organic chemistry. However, it still requires huge modifications in order to comply with the principles of green chemistry. The use of toxic chemicals, hazardous organic solvents, and the large amounts of toxic wastes that result from the reactions are a few examples of the problems that must be solved. Nanogold alone or conjugated with palladium were supported on different carriers (SiO2, C) and investigated in order to evaluate their catalytic potential for environmentally friendly alcohol oxidation under solvent-free and base-free conditions in the presence H2O2 as a clean oxidant. We tested different levels of Au loading (0.1⁻1.2% wt.) and different active catalytic site forms (monometallic Au or bimetallic Au⁻Pd sites). This provided new insights on how the structure of the Au-dispersions affected their catalytic performance. Importantly, the examination of the catalytic performance of the resulting catalysts was oriented toward a broad scope of alcohols, including those that are the most resistant to oxidation-the primary aliphatic alcohols. Surprisingly, the studies proved that Au/SiO2 at a level of Au loading as low as 0.1% wt. appeared to be efficient and prospective catalytic system for the green oxidation of alcohol. Most importantly, the results revealed that 0.1% Au/SiO2 might be the catalyst of choice with a wide scope of utility in the green oxidation of various structurally different alcohols as well as the non-activated aliphatic ones.

Photofunctionalization of dental zirconia oxide: Surface modification to improve bio-integration preserving crystal stability.

The use of zirconium oxide in dental implantology is rapidly increasing as it is regarded as being more aesthetical and biologically friendly than titanium oxide. The interaction of titanium oxide with cells and proteins has proven to be significantly affected by the inevitable atmospheric hydrocarbon contamination, defined as biological ageing. The latter has proven to be effectively reversed by UVC irradiation. Crystal structures of both Zr and Ti oxides are very similar, thus also ZrO2 is prone to contamination by hydrocarbons. In the present study we have characterized the chemical-physical changes occurring to ZrO2 after UVC irradiation. Firstly a reduction by 3-fold of carbon present on its surface. XRD analysis has indicated that UVC irradiation treatment does not affect the crystalline structure of ZrO2, suggesting that it is possible to improve cell attachment on the surface without sacrificing the mechanical strength of the material. In addition a chemical model of interaction of cell surface proteins with the almost carbon free ZrO2 surface obtainable after UVC irradiation is proposed, pointing to the important role likely played by integrins and RGD sequences originating in soluble proteins adsorbed at the cell/ZrO2 interface. Hence in clinical practice UVC photofunctionalization could improve the soft tissue seal around dental implants functioning as a valid barrier between implant and peri-implant bone, thereby improving the long-term success of implants.

Catalytic Gas-Phase Glycerol Processing over SiO2-, Cu-, Ni- and Fe- Supported Au Nanoparticles.

In this study, we investigated different metal pairings of Au nanoparticles (NPs) as potential catalysts for glycerol dehydration for the first time. All of the systems preferred the formation of hydroxyacetone (HYNE). Although the bimetallics that were tested, i.e., Au NPs supported on Ni, Fe and Cu appeared to be more active than the Au/SiO2 system, only Cu supported Au NPs gave high conversion (ca. 63%) and selectivity (ca. 70%) to HYNE.