A near-infrared reflectance analysis method for the noninvasive identification of film-coated and non-film-coated, blister-packed tablets

A non-invasive near-infrared reflectance analysis (NIRA) method has been developed to confirm the identity of blister-packed, film-coated and non film-coated tablets for clinical trial supplies. NIR spectra of the tablets were measured through the blister pack plastic using a fiber optic probe. The blister packs contained 18 cells which held pink, pentagonal tablets or film-coated, white, oblong tablets. The pink tablets contained about 80% ww of a marketed drug as a clinical comparator or were matching placebos. The white film-coated tablets contained about 60% ww of an experimental drug, about 75% ww of a marketed drug as a clinical comparator, or were matching placebos. Pattern recognition methods were developed to identify tablets in the blister pack by using libraries of second derivative NIR spectra of each tablet-type. Three chemometric methods were used, the wavelength distance method, SIMCA residual variance method, and Mahalanobis distance method. The methods were tested with full spectra (1100–2350 nm) and three subset wavelength ranges. Several of the methods reported here reliably discriminate between film-coated and non film-coated tablets, and between active and placebo tablets. Library validation and test set data are presented along with a discussion of the advantages and disadvantages of selecting subset wavelength regions.