Publications by authors named "Fumie Katoh"
Article Synopsis
- A modified version of tamoxifen, known as tamoxifen hemicitrate hydrate, was developed and characterized using various analytical techniques like X-ray diffraction and thermal analysis.
- The results indicated that the compound exists in a specific molar ratio (2:1:3 for tamoxifen:citric acid:water) and revealed the presence of multiple forms during heating, including sesquihydrate and hemihydrate.
- Additionally, the stability tests showed that tamoxifen citrate can transform into tamoxifen hemicitrate hydrate in water within 24 hours, which suggests adjustments in the manufacturing process to account for this transformation.
Article Synopsis
- The study examined the photostability of tamoxifen citrate forms A and B using various analytical techniques, including HPLC and UV/vis spectroscopy.
- Form A was found to be chemically unstable when exposed to light, showing more significant color changes compared to stable form B.
- Form A absorbed UVA light at a longer wavelength than form B, leading to degradation and color changes likely due to its selective absorption of photoenergy.
Purpose: The purpose of this study was to establish a useful methodology, possibly providing information on the stoichiometry of pharmaceutical drug salts obtained from salt screening by using a multiwell plate and a Raman microscope.
Methods: Tamoxifen salt screening was conducted with monobasic and polybasic acids on 96-well quartz plates with a Raman microscope. Appearance and crystalline forms of salts prepared on 96-well plates were observed by polarizing light microscope and Raman microscope, respectively.
Glucagon, a polypeptide hormone consisting of 29 amino acid residues, tends to form gel-like fibrillar aggregates, and the glucagon fibril, as well as other pathologically related fibrils including prion, amylin, and beta-amyloid, have been found to be cytotoxic through the activation of apoptotic signaling pathways. To understand the aggregation properties of glucagon fibril, we have characterized and compared the physicochemical properties of glucagon, secretin, a member of the glucagon superfamily, and amylin using analytical techniques including capillary electrophoresis (CE), circular dichroism (CD), FT-IR, FT-Raman, transmission electron microscopy (TEM), and beta-sheet-imaging probe. Aging treatment of glucagon resulted in the formation of fibrillar aggregates in time- and concentration-dependent manner, and FT-IR and FT-Raman analyses showed the spectral shift of amide I band, suggesting the conformational changes from alpha-helix to beta-sheet structure.
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