The influence of measurement conditions on the Hammett acidity function of solid pharmaceutical excipients

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• 作者：Andrey V. Zinchuk ; Bruno C. Hancock ; Evgenyi Y. Shalaev ; Renuka D. Reddy ; Ramprakash Govindarajan and Elizabeth Novak
• 关键词：Excipient ; Hammett acidity function ; Equivalent pH
• 刊名：European Journal of Pharmaceutics and Biopharmaceutics
• 出版年：2005
• 出版时间：2005
• 年：2005
• 卷：61
• 期：3
• 页码：158-170
• 全文大小：675 K

文摘

In this work the Hammett acidity function has been measured to assess the relative acidity of excipients used in the preparation of pharmaceutical solid dosage forms. A systematic series of experiments is reported which illustrates how the selection of the measurement conditions can influence the results of such determinations. Although the technique is somewhat empirical and relies on several key assumptions it is shown that very consistent results can be achieved by carefully controlling the measurement conditions. It is also shown that by taking this approach laboratory-to-laboratory variation can be reduced to a negligible level and the influences of subtle changes in the acidity of pharmaceutical excipients due to intrinsic variations in their physical properties or due to different processing histories can be detected and quantified.