title: Measurement uncertainty of lactase-containing tablets analyzed with FTIR.
abstract: Uncertainty is one of the most critical aspects in determination of measurement reliability. In order to ensure accurate measurements, results need to be traceable and uncertainty measurable. In this study, homogeneity of FTIR samples is determined with a combination of variographic and multivariate approach. An approach for estimation of uncertainty within individual sample, as well as, within repeated samples is introduced. FTIR samples containing two commercial pharmaceutical lactase products (LactaNON and Lactrase) are applied as an example of the procedure. The results showed that the approach is suitable for the purpose. The sample pellets were quite homogeneous, since the total uncertainty of each pellet varied between 1.5% and 2.5%. The heterogeneity within a tablet strip was found to be dominant, as 15-20 tablets has to be analyzed in order to achieve <5.0% expanded uncertainty level. Uncertainty arising from the FTIR instrument was <1.0%. The uncertainty estimates are computed directly from FTIR spectra without any concentration information of the analyte.
authors.affiliation: Lappeenranta University of Technology, Department of Chemical Technology, P.O. Box 20, FIN-53851 Lappeenranta, Finland. Electronic address: maaret.paakkunainen@lut.fi.
authors.forename: Maaret
authors.initials: M
authors.lastname: Paakkunainen
authors.forename: Jarno
authors.initials: J
authors.lastname: Kohonen
authors.forename: Satu-Pia
authors.initials: SP
authors.lastname: Reinikainen
mesh_terms: D001965:Bromides / Q000737:chemistry; D002626:Chemistry, Pharmaceutical; D043322:Lactase / Q000032:analysis* / Q000737:chemistry; D008962:Models, Theoretical; D015999:Multivariate Analysis; D017680:Potassium Compounds / Q000737:chemistry; D025341:Principal Component Analysis; D012044:Regression Analysis; D015203:Reproducibility of Results; D017550:Spectroscopy, Fourier Transform Infrared / Q000592:standards*; D013607:Tablets / Q000592:standards*; D013678:Technology, Pharmaceutical; D035501:Uncertainty
chemical_list: D001965:Bromides; D017680:Potassium Compounds; D013607:Tablets; D043322:Lactase; C039004:potassium bromide
keywords: FTIR; Principal component analysis; Spectral data; Total uncertainty; Variographic analysis