Interaction of Ampicillin and Amoxicillin with Mn2+: A Speciation Study in Aqueous Solution

Abstract

<jats:p>A potentiometric and UV spectrophotometric investigation on Mn2+-ampicillin and Mn2+-amoxicillin systems in NaCl aqueous solution is reported. The potentiometric measurements were carried out under different conditions of temperature (15 ≤ t/°C ≤ 37). The obtained speciation pattern includes two species for both the investigated systems. More in detail, for system containing ampicillin MLH and ML species, for that containing amoxicillin, MLH2 and MLH ones. The spectrophotometric findings have fully confirmed the results obtained by potentiometry for both the systems, in terms of speciation models as well as the stability constants of the formed species. Enthalpy change values were calculated via the dependence of formation constants of the species on temperature. The sequestering ability of ampicillin and amoxicillin towards Mn2+ was also evaluated under different conditions of pH and temperature via pL0.5 empirical parameter (i.e., cologarithm of the ligand concentration required to sequester 50% of the metal ion present in traces).</jats:p>

Metronidazole Interaction with Cu2+ and Zn2+: Speciation Study in Aqueous Solution and Biological Activity Evaluation

“…For this reason, determining constants under different ionic strengths is crucial to simulate real fluid conditions. Starting from the knowledge of the formation constant values at different temperatures, the enthalpy change values were calculated by using the following van’t Hoff equation: log nobreak0em0.25em⁡ β italicT = log nobreak0em0.25em⁡ β θ + normalΔ H 0 ( 1 / θ − 1 / T ) italicR nobreak0em0.25em⁡ ln nobreak0em.25em⁡ 10 where log β T is the stability constant at a certain temperature (expressed in kelvin), while log β θ is the stability constant at t = 298.15 K, and R is the universal gas constant expressed as 8.314 J K –1 mol –1 . The values of formation enthalpy changes of all of the species of Cu 2+ –L and Zn 2+ –L systems are collected in Table , together with entropy and free energy values.…”

Study on Metronidazole Acid-Base Behavior and Speciation with Ca2+ for Potential Applications in Natural Waters

“…The protonation and formation constants values acquired at the three different temperatures of 15, 25, and 37 °C, listed in Table 1 , were used to study their dependence on temperature, as already shown for several systems [ 51 , 52 ]. The data obtained by the potentiometric measurements were analyzed using the following van’t Hoff equation: logβ T = logβ θ + Δ H 0 (1/θ − 1/ T ) R ln 10 where logβ T is the stability constant at a certain temperature (expressed in kelvin), while logβ θ is the stability constant at t = 298.15 K, and R is the universal gas constant expressed as 8.314 J K −1 mol −1 .…”

Ab initio molecular dynamics simulations and experimental speciation study of levofloxacin under different pH conditions

“…To experimentally evaluate the acid-base behavior of levofloxacin under different pH values, UV-spectrophotometric titrations have been performed, following procedures already reported. [51][52][53][54] Measurements on solutions containing different concentrations of the ligand at different ionic strength values were carried out, varying the pH in the range 3 r pH r 10.5. Levofloxacin absorbs between 250 and 400 nm with two maxima at about 290 and 330 nm.…”