The hydrolytic conversion of a solid amorphous calcium phosphate of empirical formula Ca9 (PO4)6 to a poorly crystalline apatitic phase, under conditions where Ca2+ and PO4(3-) were conserved, was studied by means of solid-state magic-angle sample spinning 31P-NMR (nuclear magnetic resonance). Results showed a gradual decrease in hydrated amorphous calcium phosphate and the formation of two new PO4(3-)-containing components: an apatitic component similar to poorly crystalline hydroxyapatite and a protonated PO4(3-), probably HPO4(2-) in a dicalcium phosphate dihydrate (DCPD) brushite-like configuration. This latter component resembles the brushite-like HPO4(2-) component previously observed by 31P-NMR in apatitic calcium phosphates of biological origin. Results were consistent with previous studies by Heughebaert and Montel [18] of the kinetics of the conversion of amorphous calcium phosphate to hydroxyapatite under the same conditions.
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http://dx.doi.org/10.1007/BF02555846 | DOI Listing |
Small
January 2025
Dept. of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 7610001, Israel.
Transient amorphous phases are known as functional precursors in the formation of crystalline materials, both in vivo and in vitro. A common route to regulate amorphous calcium carbonate (ACC) crystallization is via direct interactions with negatively charged macromolecules. However, a less explored phenomenon that can influence such systems is the electrostatically driven formation of Ca-macromolecule dense phases.
View Article and Find Full Text PDFCurr Drug Deliv
January 2025
Department of Biopharmaceutical, Lishui University, 1 Xueyuan Road, Lishui, 323000, China.
Background: Overcoming the poor aqueous solubility of small-molecule drugs is a major challenge in developing clinical pharmaceuticals. Felodipine (FLDP), an L-type calcium calcium channel blocker, is a poorly water-soluble drug.
Objectives: The study aimed to explore the potential applications of polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol (Soluplus) stabilized amorphous dispersions for augmenting the oral delivery of poorly water-soluble drugs.
Bone
January 2025
Department of Preventive and Restorative Dental Sciences, School of Dentistry, University of California at San Francisco, San Francisco, CA, United States of America.
This paper presents a review of the potential role of the endoplasmic reticulum/Golgi complex and intracellular vesicles in mediating events leading to or associated with vertebrate tissue mineralization. The possible importance of these organelles in this process is suggested by observations that calcium ions accumulate in the tubules and lacunae of the endoplasmic reticulum and Golgi. Similar levels of calcium ions (approaching millimolar) are present in vesicles derived from endosomes, lysosomes and autophagosomes.
View Article and Find Full Text PDFClin Oral Investig
January 2025
Faculty of Dentistry, Department of Restorative Dentistry, Çanakkale Onsekiz Mart University, Çanakkale, 17100, Turkey.
Objectives: This study aimed to evaluate the effectiveness of home-use desensitizing agents over an 8-week period by comparing them using different measurement methods.
Methods: A randomized, controlled clinical trial was conducted with 180 individuals aged between 18 and 70 who clinically diagnosed dentin hypersensitivity (DH) in two or more non-adjacent teeth. Subjects who met the inclusion criteria (n = 164) were randomly allocated into five test groups-using Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), Arginine, Novamin, Propolis, and Potassium nitrate-and a control group using standard fluoride toothpaste.
Peptide-Ca chelates are innovative calcium supplements. possesses nutritional advantages for preparing calcium-binding peptides (CBPs), although there are limited studies on this subject. Therefore, this paper investigated the optimal condition for preparing CBPs and peptide-calcium chelates (LP-Ca), along with analyzing their microstructure, calcium-binding mechanisms, stability, and calcium transporting efficacy.
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