Quantitative Determination of Oxytetracycline in Water-Based Liquid Dosage Forms by Raman Spectroscopy

A universal method using Raman spectroscopy for the quantitative determination of oxytetracycline in three water-based medicines was developed. Five calibration models based on different mathematical data processing, i.e., one-dimensional calibration (Beer–Lambert law, classical least squares, stepwise multiple linear regression) and multi-dimensional calibration (partial least squares and principal component regression), were compared. The most accurate quantitative determinations were achieved when a calibration model based on partial least squares using two principal components was used.