SPECTROPHOTOMETRIC FINGERPRINTING AND CHEMICAL DETERMINATION OF STREPTOMYCIN, AMIKACIN, NEOMYCIN, AND GENTAMYCIN SULPHATE BY CONDENSING WITH NINHYDRIN REAGENT

Abstract

Objective: The study aimed to develop a simple, efficient, inexpensive, rapid, and reproducible spectrophotometric analytical technique for aminoglycosides analysis by condensing with ninhydrin reagent.

Methods: At a pH of 8.0, different aminoglycosides, including amikacin, gentamycin, neomycin, and streptomycin, were deaminated by the ninhydrin reagent. The working standard solution for each component was accurately placed into a series of 10 ml calibrated volumetric flasks, then 1 ml of the ninhydrin reagent was added and heated in a water bath for 15 min. The wavelength(s) of maximum absorption(s) was recorded after scanning the resultant purple complex from 350 nm to 930 nm. The final working concentrations ranged between 1600 and 2000 ug/ml.

Results: The average weight of a neomycin sulphate tablet was 0.747g, with a standard deviation of 0.667%. After complexing with ninhydrin reagent at pH 6.0 for 10 to 15 min, all aminoglycosides developed purple coloration that lasted beyond 24 h, compared to the initial white, pale yellow, and colorless appearance of streptomycin, amikacin, neomycin, and gentamycin, respectively. The scanned spectra of the purple complex of ninhydrin formed after reaction with aminoglycosides in the visible region (350-900 nm) were similar, indicating the presence of a common parent structural moiety. At 550 nm, 650 nm, 750 nm, and 850 nm, distinct absorptions were observed. Amikacin, Streptomycin, and Gentamicin had the highest absorbance between 800 and 900 nm. After the reaction with ninhydrin, three distinct absorbances were observed in the Neomycin spectrum: between 380 and 400 nm, 580 and 600 nm, and around 800 nm. The comparative spectra for the four aminoglycosides and ninhydrin reagent with blank show a unique feature for the compounds. The coefficients of regression were 0.996 and 0.995, respectively.

Conclusion: The proposed methods for analyzing streptomycin in streptomycin injections were successful. The percentage purity ranged from 017–110 % at 650 and 850 nm, which corresponds to the British Pharmacopoeia (BP) limit that streptomycin sulphate tablets should be between 97.00 and 110%.