Determination of apramycin in oral soluble powder by a HPLC method using pre-column derivatization with o-phthalaldehyde and UV detection

A high-performance liquid chromatographic method employing pre-column derivatization with o-phthalaldehyde (OPA) and 2-mercaptoacetic acid was developed for the determination of apramycin, an aminoglycoside antibiotic used in veterinary medicine, in the oral soluble powder form. The chromatographic separation was done by ion-pair HPLC using a C18 reversed-phase column, Synergy Hydro (150 mm x 4.6 mm x 4 μm) and mobile phase composed of 0.005 mol/L sodium octanosulfonate in a mixture of acetonitrile: water: acetic acid (45:55:2) (v/v/v) with a flow rate of 1.0 mL/min; the UV detector was operated at 332 nm. The developed method was validated according to official compendia guidelines, having demonstrated robustness, selectivity and linearity for the concentration range of 0.02 to 0.05 mg/mL, precision (with RSD < 2.0% both for intra and inter-day precision) accuracy (average recuperation of 99.33%) and detectivity (quantification and detection limits of 0.08 and 0.02 μg/mL, respectively). Three batches of commercial apramycin oral soluble powder were analyzed by both the proposed method and the official microbiological method, where all the results obtained were in the acceptable range (95% to 105% of labeled value of apramycin). Both methods were statistically compared by the t test, which yielded no significant differences (α = 0.05) thereby confirming the equivalence of the methods.