The present paper describes the use of near infrared spectroscopy (NIR) for the determination of moisture content in aspirin formulation. A total of one hundred seventy two samples with moisture content varying from 0.16 to 16.3% are prepared in laboratory. Near infrared spectra of these samples are collected over the wavelength region 600–2500 nm using a diffuse reflectance accessory. Reference moisture values are obtained with Karl Fischer titration method. A number of calibration models are developed using partial least squares (PLS) regression method. The best calibration model is obtained using first derivative spectra in 1100–2450 nm region with 3 PLS factor. A good correlation is obtained between NIR predicted values and reference values in calibration and validation set. The derived calibration curve is used to predict moisture content in unknown samples. The result shows that NIR spectroscopy can be successfully used for the determination of moisture content in pharmaceutical industries.
Near infrared spectroscopy, moisture content, aspirin powder, partial least squares regression
