著者

鈴木 裕介 武田 豊彦 稲津 邦平 坂元 照男 前川 秀幸

出版者

公益社団法人 日本薬学会

雑誌

YAKUGAKU ZASSHI (ISSN:00316903)

巻号頁・発行日

vol.109, no.6, pp.388-394, 1989-06-25 (Released:2008-05-30)

参考文献数

10

被引用文献数

1 1

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Cephalothin sodium (CET-Na) prepared according to the conventional freeze-drying methods is known to easily develop color during storage. Since amorphous CET-Na has been reported to be markedly unstable, the color development is thought to be due to the presence of traces of CET-Na in an amorphous state observed with scanning electron microscopy. Quantitation by use of the powder X-ray diffractometry of such traces of amorphous CET-Na has proved to be of little use. Thermogravimetry (TG) and differential scanning calorimetry (DSC) have demonstrated that the freeze-dried CET-Na by the conventional methods contains three types of CET-Na : amorphous (unstable phase), quasi-crystalline (metastable phase). Pyrolysis initiation temperatures of these three types of CET-Na have been demonstrated to become higher in this order. A new parameter for the evaluation of non-crystallinity of CET-Na has been introduced, in which the ratio is calculated from the data of the total weight loss observed through the pyrolysis of both amorphous and quasi-crystalline CET-Na against the total weight loss of all components during the pyrolysis of sample specimen. The ratio thus calculated is defined as "non-crystallinity". This new parameter has successfully been introduced to establish a good correlation to the degree of increasing color intensity with aging of freeze-dried CET-Na.