Application of Fourier transform infrared (FTIR) spectroscopy coupled with multivariate calibration for quantitative analysis of curcuminoid in tablet dosage form

Curcuminoid, especially curcumin (CUR) and desmethoxycurcumin (DMCUR), is regarded as active components of a pharmaceutical formulation containing Curcuma species responsible for several biological activities including anti-inflammatory and antioxidant. The objective of this research was to validate rapid and reliable method based on Fourier transform infrared (FTIR spectroscopy) in the mid-infrared region in combination with multivariate analysis for quantitative analysis of curcuminoid content in tablet formulation. FTIR spectra was subjected to several optimizations including wave-numbers selection and derivatization to get best prediction models for the relationship between actual values of curcuminoid as determined using high-performance liquid chromatography and FTIR calculated values. The first derivative FTIR spectra at wave-numbers of 2975-660 cm−1 using partial least square regression (PLSR) was preferred for quantification of CUR in tablet, while DMCUR was predicted using FTIR normal spectra at wave-numbers of 1784-1587 cm−1. The coefficient of determination (R2) values for calibration and validation models either in CUR and DMCUR were of >0.99 indicating good accuracy methods. The errors in calibration and validation models were low indicating the acceptable precision of the developed method. FTIR spectroscopy combined with PLS regression can be used as an alternative technique for determination of CUR and DMCUR in tablet dosage form.