title: A validated quantitative colorimetric assay for gentamicin.
abstract: A colorimetric procedure was developed for the quantification of gentamicin. The method was based on the ninhydrin reaction with primary and secondary amines present in the gentamicin. This reaction produces a purple colour. The effects of several factors including pH, ninhydrin concentration and reaction time were investigated to optimize the assay method. Using the assay protocol, the absorption of the gentamicin-ninhydrin mixtures at 400 nm had a linear relationship with the gentamicin concentration ranging from 30 to 120 microg/ml. The colorimetric gentamicin assay reported herein is of great practical value because it is reproducible, sensitive, simple and extremely inexpensive.
authors.affiliation: Department of Pharmaceutical Technology, Faculty of Pharmacy, Complutense University Madrid, Spain. pafrutos@eucmax.sim.ucm.es
authors.forename: P
authors.initials: P
authors.lastname: Frutos
authors.forename: S
authors.initials: S
authors.lastname: Torrado
authors.forename: M E
authors.initials: ME
authors.lastname: Perez-Lorenzo
authors.forename: G
authors.initials: G
authors.lastname: Frutos
mesh_terms: D003124:Colorimetry / Q000379:methods*; D005839:Gentamicins / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009555:Ninhydrin / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D005839:Gentamicins; D009555:Ninhydrin