Non-destructive prediction of the drug content of an acetaminophen suppository by near-infrared spectroscopy and X-ray computed tomography.

The purpose of this study is to develop non-destructive methods to determine the drug content of suppositories using near-infrared (NIR) spectrometry and X-ray computed tomography (XCT). The suppository samples (acetaminophen content: 0, 100, 200, 300, 400 and 500 mg/suppository) consisted of acetaminophen powder and hard fat. NIR spectra of 18 standard suppository samples were recorded, and the data were divided into two wave number ranges, 4000-10 000 cm(-1) (LR), and 4280-6650 cm(-1) (SR). The best calibration model was determined to minimize the standard error of cross-validation (SECV) by the leave-one-out method in the partial least squares regression (PLS). Sliced XCT images of the suppositories were measured, and apparent density (AD) was evaluated using the image of the sample. The NIR models gave the best correlation coefficient constant (R) values, since the results for LR and SR gave straight lines with R of 0.9274 and 0.9707, respectively. The AD of the suppositories by XCT increased with increasing drug content, and the relationship between the AD and drug content had a straight line with R of 0.9958. Both NIR and X-ray CT performed accurate measurements of suppository samples through plastic packaging.