Multiple dissociation constants of the Intepirdine hydrochloride using regression of multiwavelength spectrophotometric pH-titration data

Abstract

This manuscript has not been previously published in any language anywhere and it is not under consideration by another journal. To date, no spectra, no dissociation constants or no pHdistribution diagrams of the relative concentration of variously protonated ions of the drug Intepirdine hydrochloride INN.HCl have been published. 1) Significance of the work: Medicine and pharmacology needs physical constants (spectra, pK´s, solubility, etc.) of new drugs. 2) Novelty of the work: INN.HCl is used for the treatment of mild to moderate Alzheimer's disease and dementia with Lewy bodies. Acid-base equilibria were studied with UV-metric spectra analysis and pH-metric titration analysis. Three pK T a1 , pK T a2 , pK T a3 , of INN.HCl were determined at 25ºC and 37ºC in an aqueous medium. The number of variously protonated species was estimated from the rank of the UV-absorbance matrix. 3) Contribution to the field: Knowledge of the possible ionization states of a pharmaceutical substance, embodied in pK a , is vital for understanding properties essential to drug development.

Method of UV-Metric and pH-Metric Determination of Dissociation Constants of Ionizable Drugs: Valsartan

“…The apparatus used and both titration procedures have been described in detail [23][24][25][26][27]. The free hydrogen-ion concentration [H + ] was measured using a Hanna HI 3220 digital voltmeter having a precision of ± 0.002 pH units, using the Theta HC 103-VFR combined glass electrode.…”