Complexation equilibria of ambroxol hydrochloride in solution by potentiometric and conductometric methods

Abstract

The formation constants of Li(I), Mg(II), Sr(II), Ca(II), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Ba(II), Pb(II), Al(III), Cr(III), Fe(III) and Th(IV) ions with ambroxol hydrochloride (AMB) were calculated using the half-n value. In presence of 0.1 M NaNO3, metal ions such as Zn(II), Cd(II), Ni(II), Cr(III), Li(I), Mg(II) and Al(III) forms three types of metal-ligand complexes (1:1, 1:2 and/or 1:3), while Sr(II) and Co(II) tend to form two types of metal complexes 1:1 and 1:2 (M:L). For ligand protonation constants, two logarithmic association constant values were calculated by the half-n method and are 10.7 and 7.6, respectively. The effect of ionic strength on stability constant of AMP, with different metal ions viz. Fe(III), Th(IV), Al(III), Cr(III) and Cu(II) was studied. Based on relationship between the ionic strength studied values and the 1st stability constants (Log K1H), we can conclude that the stability constants of the formed metal-ligand complex (1:1) were decreased as the ionic strength increased. The stoichiometry of the formed complexes in solution were determined by conductometric method and it is found to be of 1:1, 1:2 and/or 1:3 (M:L) complex species is formed in alkaline media. Also, study the species distribution diagrams of AMP for the calculated mole fraction αML and αML2 were discussed.

Developing Metal Complexes for Captopril Quantification in Tablets Using Potentiometric and Conductometric Methods

“…The use of potentiometric and coductometric methods to analyze the binary and trinary complexes formed between metals and biological and pharmacological compounds has attracted a lot of interest as electrochemical methods. − CAP was previously determined using potentiometric − and conductometric − methods. The potentiometric assessment of complex formation among both stimulants and metal ions gives a clear overview of how interactions between drugs and metals may affect medication delivery to target areas. , In biological fluids, the presence of certain ions is thought to have a major impact on the pharmacological actions of some chemical substances …”