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The aim of this study is to investigate the influence of polymer chemistry on the properties of oral dosage forms produced using selective laser sintering (SLS). The dosage forms were printed using different grades of polyvinyl alcohol or copovidone in combination with indomethacin as the active pharmaceutical ingredient. The properties of the printed structures were assessed according to European Pharmacopoeia guidelines at different printing temperatures and laser scanning speeds in order to determine the suitable printing parameters.The results of the study indicate that the chemical properties of the polymers, such as dynamic viscosity, degree of hydrolyzation, and molecular weight, have significant impact on drug release and kinetics. Drug release rate and supersaturation can be modulated by selecting the appropriate polymer type. Furthermore, the physical properties of the dosage forms printed under the same settings are influenced by the selected polymer type, which determines the ideal manufacturing settings.This study demonstrates how the chemical properties of the polymer can determine the appropriate choice of manufacturing settings and the final properties of oral dosage forms produced using SLS.

Ion conduction in three-layered ion-conductor systems is considered. Explicit analytic expressions for the isothermal transient ionic current and frequency-dependent impedance are derived. The analysis includes migration, diffusion and space-charge effects as contributors to the ionic motion. The resulting model allows conduction parameters such as diffusion coefficients and ion concentrations in three different layers to be obtained from one single measurement, either in the time or in the frequency domain. The implications of one or more of the layers being mixed ionic/electronic conductors are discussed, and it is argued that the proposed model provides a useful description of the coupled ionic/electronic motion occurring in such a mixed-conductor system. [ABSTRACT FROM AUTHOR]

Temperature dependent ac dielectric spectroscopy and room-temperature I–V characterization were performed on atomic layer deposited (Ta[sub 1-x]Nb[sub x])[sub 2]O[sub 5] films. The high frequency permittivity, as well as the dc conductivity of the films, were found to increase with increasing Nb content. The conduction mechanism in the mixed Ta–Nb oxide films was of the Poole–Frenkel type, while the high field conduction in pure Ta[sub 2]O[sub 5] was space-charge limited. The activation energy for dc conduction was higher in mixed Ta–Nb oxides compared to pure Ta[sub 2]O[sub 5] and Nb[sub 2]O[sub 5] films. Irreversible changes in the conduction mechanism took place upon heat treatment above a certain irreversibility temperature. This temperature was higher for the mixed oxides than for the binary ones. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

At present, the peculiar compound called oxymagnesite, MgO⋅2MgCO3, an intermediate formed during thermal decomposition of hydrated magnesium carbonates, has only been described a handful of times without a distinct description of its formation or morphology. In the current work we present the first scanning and transmission electron microscopy images of an oxymagnesite crystal together with its crystallographic data. Oxymagnesite was synthesized in a controlled manner decomposition of via amorphous magnesium carbonates (AMCs) subjected to varying relative humidity. We show that oxymagnesite is formed only when AMC is hydrated above a certain level, which we attribute to structural inequivalence between CO3 groups induced by water in AMC subjected to high humidity resulting in a weakening of some of the Mg-CO3 bonds. The study provides an understanding of the conditions needed for oxymagnesite formation and shows how hydrated AMCs can be used as precursors of different types of magnesium carbonates. [ABSTRACT FROM AUTHOR]

The experimental investigation of the cubic δ-Bi2O3 phase grown on a (110) Au substrate at low temperature has disclosed a chaotic character of the conductivity at low voltage and temperature. Based on first-principles calculations, we show that the conductivity of this oxide strongly depends on the distribution of oxygen ions and that oxygen migration is able to cause a momentary switch of the conduction mechanism. [ABSTRACT FROM AUTHOR]

The percolation theory is established as a useful tool in the field of pharmaceutical materials science. It is shown that percolation theory, developed for analyzing insulator-conductor transitions, can be applied to describe imperfect dc conduction in pharmaceutical microcrystalline cellulose during densification. The system, in fact, exactly reproduces the values of the percolation threshold and exponent estimated for a three-dimensional random continuum. Our data clearly show a crossover from a power-law percolation theory region to a linear effective medium theory region at a cellulose porosity of ∼0.7. [ABSTRACT FROM AUTHOR]

Pharmacies are currently unable to stock proper oral dosage forms for pediatric populations. This leads to manipulation of medications or the need to compound specialized medications, which can be a time-consuming process. Using Semisolid Extrusion (SSE) additive manufacturing (AM), specialized medications can be produced in an expedited process from off-the shelf medication in a hospital or outpatient pharmacy setting. In this study, tablets with a desired dose of 5 mg of metoprolol tartrate derived from commercial Seloken™ 50 mg tablets were 3D printed in a hospital setting. Validation testing was done on five batches, highlighting tablets with a high uniformity in mass and dimension, drug content, acceptable microbial assays, and prolonged release during in-vitro analysis. The average drug content found for the tablets was within ±6% of 5 mg for all batches produced. Comparisons were done between the SSE tablets and capsules produced in an external compounding facility, highlighting several positive aspects of SSE-produced tablets beyond simply shortening the production timeline. The SSE tablets printed in this study are characterized by their smaller size, enhanced prolonged release properties, and more uniform drug content across the tested samples. Additionally, interviews with pharmaceutical professionals were conducted to determine the positive aspects of SSE and further improvements to bring this technique as seamlessly as possible into the pharmacy. This study underscores the feasibility of employing SSE in the production of specialized medications within a hospital environment. Furthermore, it highlights the methodological advantages SSE offers over existing production standards, demonstrating its potential to improve pharmaceutical manufacturing in healthcare settings., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests. Jonas Lindh reports financial support was provided by Sweden's Innovation Agency. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Engineering the building blocks in metal-organic materials is an effective strategy for tuning their dynamical properties and can affect their response to external guest molecules. Tailoring the interaction and diffusion of molecules into these structures is highly important, particularly for applications related to gas separation. Herein, we report a vanadium-based hybrid ultramicroporous material, VOFFIVE-1-Ni, with temperature-dependent dynamical properties and a strong affinity to effectively capture and separate carbon dioxide (CO 2 ) from methane (CH 4 ). VOFFIVE-1-Ni exhibits a CO 2 uptake of 12.08 wt % (2.75 mmol g -1 ), a negligible CH 4 uptake at 293 K (0.5 bar), and an excellent CO 2 -over-CH 4 uptake ratio of 2280, far exceeding that of similar materials. The material also exhibits a favorable CO 2 enthalpy of adsorption below -50 kJ mol -1 , as well as fast CO 2 adsorption rates (90% uptake reached within 20 s) that render the hydrolytically stable VOFFIVE-1-Ni a promising sorbent for applications such as biogas upgrading.

A wide array of carbon materials finds extensive utility across various industrial applications today. Nonetheless, the production processes for these materials continue to entail elevated temperatures, necessitate the use of inert atmospheres, and often involve the handling of aggressive and toxic chemicals. The prevalent method for large-scale carbon material production, namely the pyrolysis of waste biomass and polymers, typically unfolds within the temperature range of 500-700 °C under a nitrogen (N 2 ) atmosphere. Unfortunately, this approach suffers from significant energy inefficiency due to substantial heat loss over extended processing durations. In this work, we propose an interesting alternative: the carbonization of photothermal nanocellulose/polypyrrole composite films through CO 2 laser irradiation in the presence of air. This innovative technique offers a swift and energy-efficient means of preparing carbon materials. The unique interaction between nanocellulose and polypyrrole imparts the film with sufficient stability to retain its structural integrity post-carbonization. This breakthrough opens up new avenues for producing binder-free electrodes using a rapid and straightforward approach. Furthermore, the irradiated film demonstrates specific and areal capacitances of 159 F g -1 and 62 μF cm -2 , respectively, when immersed in a 2 M NaOH electrolyte. These values significantly surpass those achieved by current commercial activated carbons. Together, these attributes render CO 2 -laser carbonization an environmentally sustainable and ecologically friendly method for carbon material production., (© 2024 The Authors. ChemSusChem published by Wiley-VCH GmbH.)