Determination of pKa values of alendronate sodium in aqueous solution by piecewise linear regression based on acid-base potentiometric titration  

作　　者：Jing Ke Hanfei Dou Ximin Zhang Dushimabararezi Serge Uhagaze Xiali Ding Yuming Dong 

机构地区：[1]Institute of Pharmaceutical Analysis,School of Pharmacy,Lanzhou University [2]Key Laboratory of Gansu Province Chinese Medicine Preparation of Solid Dispersion,Gansu longshenrongfa Pharmaceutical Industry Co.,Ltd.

出　　处：《Journal of Pharmaceutical Analysis》2016年第6期404-409,共6页药物分析学报（英文版）

基　　金：the support of Key Laboratory of Chinese Medicine Preparation of Solid Dispersion,Gansu Longshenrongfa Pharmaceutical Industry Co.,Ltd.,Gansu Province,China

摘　　要：As a mono-sodium salt form of alendronic acid,alendronate sodium presents multi-level ionization for the dissociation of its four hydroxyl groups.The dissociation constants of alendronate sodium were determined in this work by studying the piecewise linear relationship between volume of titrant and p H value based on acidbase potentiometric titration reaction.The distribution curves of alendronate sodium were drawn according to the determined p Ka values.There were 4 dissociation constants(pKa_1=2.43,pKa_2=7.55,pKa_3=10.80,pKa_4=11.99,respectively) of alendronate sodium,and 12 existing forms,of which 4 could be ignored,existing in different p H environments.As a mono-sodium salt form of alendronic acid, alendronate sodium presents multi-level ionization for the dissociation of its four hydroxyl groups. The dissociation constants of alendronate sodium were determined in this work by studying the piecewise linear relationship between volume of titrant and pH value based on acid-base potentiometric titration reaction. The distribution curves of alendronate sodium were drawn according to the determined pKa values. There were 4 dissociation constants (pKa<SUB>1</SUB>=2.43, pKa<SUB>2</SUB>=7.55, pKa<SUB>3</SUB>=10.80, pKa<SUB>4</SUB>=11.99, respectively) of alendronate sodium, and 12 existing forms, of which 4 could be ignored, existing in different pH environments.

关 键 词：Dissociation CONSTANTS ALENDRONATE SODIUM Distribution curve Piecewise linear regression ACID-BASE POTENTIOMETRIC TITRATION 

分 类 号：R914[医药卫生—药物化学]