Abstract Acid dissociation constants are important parameters for indicating the extent of dissociation at different pH values, which is directly reflected in the absorption and elimination of drugs. In this present study, the acid–base equilibrium of guttiferone-A — an important natural benzophenone with innumerable biological activities — was investigated. The p K a values were determined, via the spectrophotometric method, in six different ethanol–water mixtures, and a significant linear correlation for p K a 2 as a function of the alcohol percentage was found. A proposition was made for the order of the dissociation sites of the guttiferone-A, based on the value of p K a for the 7-epiclusianone. The modeling and the study of sensitivity enabled the molar absorptivity spectra as well as the regions of highest sensitivity for inversion of the constants to be obtained. Complementing this study, the bootstrap of residuals technique was evaluated for assessment of the confidence intervals for the fitted constants — the results were equivalent to those encountered via the parametric method.

中文翻译：

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乙醇-水混合物中古替芬 A 的酸碱平衡：不确定性的建模和基于引导的评估

摘要 酸解离常数是表征不同pH值下解离程度的重要参数，直接反映在药物的吸收和消除中。在本研究中，研究了古蒂芬酮-A（一种具有无数生物活性的重要天然二苯甲酮）的酸碱平衡。p K a 值是通过分光光度法在六种不同的乙醇-水混合物中确定的，并且发现 p K a 2 作为酒精百分比的函数的显着线性相关性。根据 7-epiclusianone 的 p K a 值，提出了古蒂法酮-A 解离位点的顺序。灵敏度的建模和研究使得能够获得摩尔吸光度谱以及常数反演的最高灵敏度区域。作为这项研究的补充，残差技术的 bootstrap 用于评估拟合常数的置信区间 - 结果与通过参数方法遇到的结果相同。