Determination of Diclofenac Diethylamine Levels in Emulgel Preparations Using NIR Spectroscopy Combined with Chemometrics

Diclofenac is an NSAID-class drug with activity as an analgesic and anti-inflammatory recommended for treating various acute and chronic pain conditions. One of the topical preparations of diclofenac that is often used is emulgel. In this study, diclofenac diethylamine levels in emulgel preparations were determined using NIR (Near-Infrared) spectroscopy and chemometric methods. Simulation samples were prepared and divided into 24 training sets and 9 test set samples. NIR spectra of training set samples were correlated with the concentration of diclofenac diethylamine using partial least squares (PLS), principal component regression (PCR), and support vector regression (SVR). The best model was validated using leave one out cross validation (LOOCV) and external validation using test set samples. The comparison method used in this study was the validated TLC Densitometry method. The best calibration model was PLS, with an R2 value of 0.990 and RMSE of 0.171. The results of R2 and RMSE of LOOCV were 0.989 up to 0.990 and 0.167 up to 0.178, respectively. The result of R2 and RMSEP external validation were 0.991 and 0.146, respectively. The precision and accuracy method showed RSD of 3.37% and a % recovery of 99.78%. The results of determining the sample levels obtained from NIR and TLC Densitometry methods tested with the Two-Paired Sample T Test and showed that the two methods have no significant differences with a significance value of more than 0.05.