Simultaneous determination and validation of doxycycline and neomycin by RP-HPLC in bulk drug and pharmaceutical formulations

Abstract

An accurate, simple, reproducible and sensitive method for the simultaneous determination of Doxycycline and Neomycin was developed and validated as per ICH Guidelines. Doxycycline and Neomycin were separated by HPLC using a Shimadzu RP-18 column (5µm,250mmⅹ4.6mm i.d) and isocratic elution with a flow rate of 1 mL/min. Mixture of Acetonitrile and Methanol (pH=8.9) (50/50) was used as mobile phase. The detection was at 258 nm wavelength. The retention time of DOXY and NEOM was found to be 5.402 and 2.94 min respectively. The linearity of developed method was achieved in the range of 25-125 µg/mL (r2 = 0.9992) and 5-25 µg/mL (r2 = 0.9995) for Doxycycline and Neomycin respectively. LOD of both the drugs were 0.8406 µg/mL and 0.0427 µg/mL and LOQ was found to be 2.547 µg/mL and 0.129 µg/mL for Doxycycline and Neomycin respectively. Recovery and assay studies of Doxycycline and Neomycin were within 99% to 102% indicating that the proposed method is suitable for routine analysis of ophthalmic formulation.