TY - JOUR
T1 - Towards a robust water content determination of freeze-dried samples by near-infrared spectroscopy
AU - Grohganz, Holger
AU - Gildemyn, Delphine
AU - Skibsted, Erik
AU - Fink, James M.
AU - Rantanen, Jukka Tapio
PY - 2010/8
Y1 - 2010/8
N2 - The possibility for determination of the water content in pharmaceutical samples by near-infrared (NIR) spectroscopy has been more widely investigated in the past few years. However, many studies claim that changes in sample composition will require the establishment of a new method. The aim of this study was several fold: firstly to investigate validation aspects of water content determination in samples with varying composition and furthermore to see if a model based solely on freeze-dried mannitol-sucrose mixtures can be established that will be able to predict water contents for samples containing proteins, excipients or having a lower density of freeze-dried solids. Samples were measured by NIR, standard normal variate (SNV) corrected and the obtained spectra were compared with the results from a conventional Karl-Fischer titration by means of multivariate analysis, namely principal component analysis (PCA) and partial least square regression (PLS). For the overall sample set, a highly linear correlation between the NIR and the Karl-Fischer method with a slope of 1.00, an R2 value of 0.98 and a root mean square error of cross-validation (RMSECV) of 0.15% were found. In a second step samples solely consisting of mannitol and sucrose mixtures were used to build a calibration set, which resulted in a RMSECV of 0.16%. The prediction of the remaining samples, which included protein or excipient containing samples, as well as lower density samples, resulted in a root mean square error of prediction (RMSEP) of 0.19%. Thus the present study demonstrated, that a general model for the determination of the water content by NIR could be established, within the limits investigated.
AB - The possibility for determination of the water content in pharmaceutical samples by near-infrared (NIR) spectroscopy has been more widely investigated in the past few years. However, many studies claim that changes in sample composition will require the establishment of a new method. The aim of this study was several fold: firstly to investigate validation aspects of water content determination in samples with varying composition and furthermore to see if a model based solely on freeze-dried mannitol-sucrose mixtures can be established that will be able to predict water contents for samples containing proteins, excipients or having a lower density of freeze-dried solids. Samples were measured by NIR, standard normal variate (SNV) corrected and the obtained spectra were compared with the results from a conventional Karl-Fischer titration by means of multivariate analysis, namely principal component analysis (PCA) and partial least square regression (PLS). For the overall sample set, a highly linear correlation between the NIR and the Karl-Fischer method with a slope of 1.00, an R2 value of 0.98 and a root mean square error of cross-validation (RMSECV) of 0.15% were found. In a second step samples solely consisting of mannitol and sucrose mixtures were used to build a calibration set, which resulted in a RMSECV of 0.16%. The prediction of the remaining samples, which included protein or excipient containing samples, as well as lower density samples, resulted in a root mean square error of prediction (RMSEP) of 0.19%. Thus the present study demonstrated, that a general model for the determination of the water content by NIR could be established, within the limits investigated.
KW - Former Faculty of Pharmaceutical Sciences
U2 - 10.1016/j.aca.2010.07.035
DO - 10.1016/j.aca.2010.07.035
M3 - Journal article
C2 - 20800739
SN - 0003-2670
VL - 676
SP - 34
EP - 40
JO - Analytica Chimica Acta
JF - Analytica Chimica Acta
ER -