Introduction: Gentamicin sulfate is an aminoglycosidic antibiotic, used in severe infections caused by Gram-negative bacteria. UV-Vis spectrophotometry, a simple, high speed and accessible analytical method, is generally suitable for the quantitative determination of pharmaceutical active ingredients in raw materials. In the case of gentamicin, a drug that presents low absorbances on the UV-Vis domain, direct determination by UV-Vis spectrophotometry would not assure adequate detection and quantitation limits.
The aim of this study was to develop a new indirect spectrophotometric method, based on the capacity of gentamicin to form in the presence of Cu2+ ions complex combinations with increased UV-Vis light absorbing capacity.
Material and method: Optimised experimental conditions which assure formation of a stable complex was found to take place in the pre-sence of CuCl2.6H2O 0.1 mg/mL, while 1 mM NaOH was used as solvent. All readings were performed at 291 nm on the first derivative of the absorbance spectrum.
Results: The developed method was validated, and proved to be linear on the 0.051–0.261 mg/mL concentration range (r = 0.99935).
Conclusions: The developed method is fast, accessible and can be used for the determination of gentamicin in raw materials.