Application of Fourier-transform infrared (FT-IR) transmission spectroscopy for the estimation of roxithromycin in pharmaceutical formulations

A quick and reliable analytical method for the quantitative assessment of roxithromycin in pharmaceutical formulations was developed using Fourier-transform infrared (FT-IR) transmission spectroscopy for routine quality control. The sample preparation was avoided except grinding for pellet formation and eliminated the use of toxic solvents. For the determination of roxithromycin, conventional KBr was used in the form of pellets for acquisition of the FT-IR spectra of standards and samples. The calibration model was developed based on simple Beer's law using the FT-IR carbonyl region (CO) from 1765 to 1705 cm⁻¹. The excellent coefficient of determination (R²) was achieved (0.9992) with 0.01 mg standard error of calibration. This work clearly revealed the capability of the transmission FT-IR spectroscopy and extended its application for determining the exact quantity of roxithromycin to control the processing formulation and quality of finished product with the analysis time of less than 3 min using the neat solid samples.