Chemometrics-assisted UV-spectroscopy for simultaneous determination of curcumin and piperine in solid dispersion-based microparticles containing Curcuma longa and Piper nigrum extracts

: Piperine and curcumin can be combined in a mixture as piperine has been known as a bioenhancer. The piperine-curcumin combination was formulated in a solid dispersion-based microparticle containing Piper nigrum and Curcuma longa extracts. The aim of the study was to simultaneously determine piperine and curcumin concentrations in a combined dosage form of solid dispersion-based microparticles using UV-Vis spectrophotometry. A UV-Vis spectrophotometry was combined with a partial least square (PLS) approach with a central composite design (CCD) to develop a calibration series consisting of 36 standard mixtures of piperine and curcumin at concentrations ranging from 0 to 6 g/mL. The model of the calibration series was validated for determination coefficient ( R 2 ), root means square of error prediction/cross-validation (RMSEP/RMSECV) dan predicted residual sum of square (PRESS). Accuracy and precision were determined as per ICH guidelines. The PLS model was successfully validated and applied for resolving overlaid spectra of piperine and curcumin at 206 – 408 nm. Accuracy and precision studies of prepared samples containing a mixture of piperine and curcumin at low, medium, and high concentrations conducted on different days were met with the AOAC International requirements. The limit of detection (LOD) was determined using a pseudo-variates model, and the limit was found to be 0.25 µ g/mL and 0.33 µ g/mL for piperine and curcumin, respectively. The proposed method is suitable for simultaneously determining piperine and curcumin that appeared in a mixture of P. nigrum and C. longa extracts in the solid dispersion-based microparticle samples.