Spectroscopic Study for Determination of Amoxicillin Using Cobalt(II) as Complexing Metal

Abstract

This study includes analytical methods for the determination of the drug amoxicillin trihydrate (Amox.) in some pharmaceutical preparations using Cobalt ion (Co(II)) as complexing metal. The best conditions for complexation were: the reaction time was 20 minutes, pH=1.5 and the best temperature of reaction was 70 ËšC. Benzyl alcohol was the best solvent for extraction the complex.
 Keywords: Amoxicillin, Cobalt(II), Complex, Molar ratio.

Mechanochemical synthesis, characterization and antimicrobial screening of Metal (II) complexes derived from amoxicillin

“…The interaction between amoxicillin and the metal salts yielded coloured complexes of blue, brown and yellow cream for Co(II), Fe(II) and Mn(II) complexes respectively,which is similar with the result reported by Al-Mudhafar, (2009). Amoxicillin melted at a temperature of 189 o C where as its interaction with metal (II) ions resulted complexes with decomposition temperatures of 278 o C, 217 o Cand 245 o C for Co(II), Fe(II)and Mn(II) complexes respectively.…”

“…The bands at 1689.54cm -1 and 1774.50cm -1 in the spectrum of free amoxicillin are assigned to υ(C=O) of amide and carboxylic acid respectively, as these shifted to different frequencies, 1599.51cm -1 and 1778.83cm -1 , 1584.78cm -1 and 1778.92cm -1 , 1737.91cm -1 and 1778.93cm -1 , for Amox-Co(II), Amox-Fe(II)and Amox-Mn(II) respectively, which suggested the coordination of carboxylic oxygen after deprotonating (Waziri et al, 2017) The bands at the range 575.26cm -1 , 579.09cm -1 and 553.00cm -1 , in the spectra of amoxicillin complexes which could not traced to the free ligand spectrum is tentatively assigned to M-O stretching frequencies for Co(II), Fe(II)and Mn(II). Similar amoxicillin complexes have been reported by other researchers (Imran et al, 2006;Waziri, et al, 2017;Reiss et al, 2015;Al-Mudhafar, 2009) (2009), supporting coordination of Amoxicillin to respective metal ions as shown in Table 4. Estimation of the Metal to Ligand ratio was achieved by using Job's method of continuous variation, the results showing mole fraction of the Ligand and absorbance for the respective metal ions (Co 2+ , Fe 2+ and Mn 2+ ) are presented in Table 5 as reported in the literature by (Skoog et al, 2007).…”