Mechanism of phosphate adsorption to a three-dimensional structure of boehmite in the presence of bovine serum albumin
| Autor: | Yoshiyuki Yoshimura, Keisuke Ishida, Yuko Hashimura, Mikio Nishida, Kenta Ooi, Jun Kawada, Akira Ookubo, Atsuya Ikawa |
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| Rok vydání: | 1993 |
| Předmět: |
Boehmite
Nitrogen Pharmaceutical Science Aluminum Hydroxide Ligands Phosphates chemistry.chemical_compound Adsorption X-Ray Diffraction Desorption Aluminum Oxide Humans Bovine serum albumin Particle Size Aqueous solution Chromatography Gastric Juice biology Serum Albumin Bovine Microporous material Phosphate chemistry Chemical engineering biology.protein Microscopy Electron Scanning Thermodynamics Mesoporous material Porosity |
| Zdroj: | Journal of pharmaceutical sciences. 82(7) |
| ISSN: | 0022-3549 |
| Popis: | A new microcrystalline boehmite (tentatively named PT-A) was synthesized as an efficient phosphate adsorbent to replace aluminum hydroxide gel. The characteristic structure of PT-A was examined by nitrogen adsorption/desorption, X-ray diffraction, deviation microscopy, and scanning electron microscopy to establish a pore structural model of PT-A. With this model structure, the details of the mechanism of interaction between PT-A and phosphate in the presence of bovine serum albumin (BSA) are discussed. PT-A is a spherical particle with a diameter of approximately 100 microns and a porous surface structure, and its inside is packed with boehmite microcrystals (crystallite size, 2 nm). PT-A has three types of pores in its structure: a micropore with a narrow size-distribution, a mesopore with a broad size-distribution, and a macropore (radii of pores are 0.7, 1-20, and approximately 300 nm, respectively). When phosphate was incubated with PT-A in human gastric and intestinal juices or in an aqueous solution containing BSA, the amounts of phosphate adsorbed by PT-A were not affected by the presence of proteins. The nitrogen adsorption/desorption isotherms and energy dispersive X-ray analyses demonstrated that phosphate could diffuse to the smaller tunnels freely even if the external surface of PT-A was covered with BSA. It was also demonstrated that the main site of adsorption for phosphate was in micropores of PT-A, whereas BSA was adsorbed only to the external surface and none entered inside smaller tunnels consisting of micro- and mesopores. |
| Databáze: | OpenAIRE |
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