Amorphous solid dispersions are used as a strategy to improve the bioavailability of poorly water-soluble compounds. When formulating with a polymer, it is important not only for the polymer to stabilize against crystallization in the solid state, but also to improve the dissolution profile through inhibiting crystallization from the supersaturated solution generated by dissolution of the amorphous material. In this study, the dissolution profiles of solid dispersions of felodipine formulated with poly(vinylpyrrolidone) (PVP), hydroxypropyl methylcellulose (HPMC) or hydroxypropyl methylcellulose acetate succinate (HPMCAS) were compared. In addition, concentration versus time profiles were evaluated for the supersaturated solutions of felodipine in the presence and absence of the polymers. HPMCAS was found to maintain the highest level of supersaturation for the greatest length of time for both the dissolution and solution crystallization experiments, whereas PVP was found to be the least effective crystallization inhibitor. All polymers appeared to reduce the crystal growth rates of felodipine at an equivalent supersaturation and this mechanism most likely contributes to the enhanced solution concentration values observed during dissolution of the amorphous solid dispersions.
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http://dx.doi.org/10.1016/j.ejpb.2008.05.023 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
KU Leuven, Materials engineering, Kasteelpark Arenberg 44 bus 2450, 3001 LEUVEN Belgium, LEUVEN, BELGIUM.
Traditional polymer solid electrolytes (PSEs) suffer from low Li conductivity, poor kinetics and safety concerns. Here, we present a novel porous MOF glass gelled polymer electrolyte (PMG-GPE) prepared via a top-down strategy, which features a unique three-dimensional interconnected graded-aperture structure for efficient ion transport. Comprehensive analyses, including time-of-flight secondary ion mass spectrometry (TOF-SIMS), Solid-state 7Li magic-angle-spinning nuclear magnetic resonance (MAS-NMR), Molecular Dynamics (MD) simulations, and electrochemical tests, quantify the pore structures, revealing their relationship with ion conductivity that increases and then decreases as macropore proportion rises.
View Article and Find Full Text PDFAnal Methods
January 2025
Rede Nordeste de Biotecnologia, Universidade Federal de Sergipe, São Cristóvão, SE 49100-000, Brazil.
Analytical chemistry demands precise sample preparation methods to ensure accurate qualitative and quantitative determinations, especially those capable of clean-up and preconcentration of target analytes. Extraction plays a crucial role in enhancing the selectivity and sensitivity of analytical procedures. Thus, Energized Dispersive Guided Extraction (EDGE) has emerged as an innovative alternative to traditional methods, such as Soxhlet, maceration, and percolation, as well as modern techniques like Accelerated Solvent Extraction (ASE), Supercritical Fluid Extraction (SFE), and Microwave or Ultrasound Assisted Extraction (MAE and UAE).
View Article and Find Full Text PDFEnviron Monit Assess
January 2025
Department of Environmental Sciences, Central University of Himachal Pradesh, Dharamshala, Kangra, Himachal Pradesh, India.
Improper and unscientific management of municipal solid waste (MSW) landfill sites has increasingly become a pressing environmental issue especially in the mountainous regions worldwide. In view of this, an attempt was made to assess the detrimental effects of MSW landfill on the natural water sources at Dharamshala, Himachal Pradesh. Further, the suitability of potential landfill site and dispersion of pollutant air masses were stipulated using Arc GIS and HYSPLIT model.
View Article and Find Full Text PDFJ Food Sci
January 2025
Department of Chemistry, University of Isfahan, Isfahan, Iran.
Quercetin, a key flavonoid found in many fruits and vegetables, offers notable health benefits, including antioxidant, antiviral, and antitumor properties. Yet, isolating it from complex plant materials is challenging. This research aimed to develop a selective and efficient sorbent to clean up real sample matrices and pre-concentrate quercetin, enhancing its detection using high-performance liquid chromatography (HPLC).
View Article and Find Full Text PDFEur J Pharm Sci
January 2025
Faculty of Pharmacy, University of Ljubljana, 1000 Ljubljana, Slovenia; KRKA, d. d., 8501 Novo Mesto, Slovenia.
One of the main concerns with formulations containing amorphous solid dispersions (ASDs) is their physical stability. Stability can be compromised if a formulation contains any residual crystallinity of an active pharmaceutical ingredient (API) that could act as seeds for further crystallisation. This study presents four methods for crystalline amlodipine maleate quantification in ASD, which were developed using one Raman and three NIR process analysers.
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