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R De Maesschalck

Publications and source records attributed to R De Maesschalck.

3 recordsLinked to original sources

Evaluation of dissolution profiles using principal component analysis.

The performance of principal component analysis (PCA) for the evaluation of dissolution profiles is examined and compared with other methods such as the similarity factor and the calculation of the area under the curve. Both simulated and real data from the pharmaceutical industry are used. The PCA scores plots of the dissolution curves provide information about the between- and within-batch variations. Differences in level or shape can be observed in the first two principal components (PCs). Irrelevant irregularities, which have a strong influence on the similarity factor, are neglected in PC1/PC2. To detect outliers in a set of dissolution curves, PCA was preferred above Hotelling's T2 test. In general, PCA is found to be a useful technique to examine dissolution data visually, but however, it does not contain criteria to decide if batches are similar or not. This can be done by combining PCA with the resampling with replacement or bootstrap method to construct confidence limits.

Solubility↗

Identification of pharmaceutical excipients using NIR spectroscopy and SIMCA.

Soft independent modelling of class analogy (SIMCA) is applied to identify near-infrared (NIR) spectra of ten excipients used in the pharmaceutical industry. For each class at least 15 excipient samples were collected for the data base, considering different batches and occasionally various suppliers. Therefore the data of the classes are not always homogeneous. The performance of the original SIMCA method, which is usually described in the literature and also applied by the users, carried out at two confidence levels, 95 and 99%, on original data, SNV (standard normal variate transformation) and second derivative pre-processed data, is discussed. Reasons for the rejection rates are given. No objects were assigned to a wrong class using SIMCA.

Drug Industry↗

The influence of data pre-processing in the pattern recognition of excipients near-infrared spectra.

The effect of data pre-processing (no pre-processing, offset correction, de-trending, standard normal variate transformation (SNV), SNV + de-trending, multiplicative scatter correction, first and second derivative transformation after smoothing) on the identification of ten pharmaceutical excipients is investigated. Four pattern recognition methods are tested in the study, namely the Mahalanobis distance method, the SIMCA residual variance method, the wavelength distance method and a method based on triangular potential functions. The performance of the 32 method combinations is evaluated on the basis of two NIR data sets. The first one, measured in 1994, is used to build the classification models, the second, measured from 1994-1997, is used to assess the quality of the models. The best approach for the given data sets is the wavelength distance method combined with de-trending, a simple baseline correction method. More general recommendations for pre-processing excipient NIR data and for choosing an appropriate classification method are given.

Excipients↗