PLS scores images

A partial least square type two (PLS 2) analysis was employed, based on a library of the three API pure components. Applying the model in classification mode to the sample data set results in PLS score images that show the spatial distribution of the three API components. 

The PLS scores images for acetaminophen, aspirin and caffeine highlighting high concentration areas for each chemical components are shown in Figure 8.11A-C. Contrast in these score images is based on the... 

Figure 8.11 An OTC analgesic tablet (Excedrin) with three APIs. Spatial distribution of each API was obtained using PLS analysis. (A-C) PLS score images of acetaminophen, aspirin, and caffeine, respectively and (D-F) single-pixel microspectra (solid line) compared to pure component acetaminophen, aspirin, and caffeine spectra (dashed line), respectively.

Figure 8.12 Histograms of PLS score images. (A) acetaminophen (B) aspirin and (C) caffeine.

Figure 8.15 (A-F) hiistogram representations of the PLS score images showing the statistical distributions of the API class. Heterogeneity In the blend Is Indicated by deviations from a normal distribution and can be expressed as percent standard deviation (%SD), calculated by dividing the standard deviation by the mean.

Figure 8.16 Analysis of selected areas of the best laboratory blend (Tablet E) and the commercial blend (tablet F). (a) Truncated PLS score imaged for the API component (depicted as white) from the central region of the tablets showing that on a local scale, the blending in both samples is uniform and (b) histograms and resulting %SD of the distribution from the truncated images. Note that both examples display nearly normal distributions.

Figure 7.10 Chemical image analysis of six tablets composed of 80 mg of furosemide (API) mixed with 240mg of the excipient mix (99.7% Avicel PH 102 and 0.33% magnesium stearate). Tablets A-E were created in the laboratory using increasing blending time, tablet F is an example of a commercial product. These PLS score images of the tablets highlight the location of the API component (bright pixels), and show the gross blend-quality differences.

Figure 2.8 (a), (b) and (c) The figures shows the PLS score images for acetaminophen, aspirin, and caffeine, respectively. Each image is scaled independently, and only represents qualitative information about the component distributions. 

Table 2.3 Individual normalized standard deviation values of histogram distributions from PLS score images a measure of sample heterogeneity for individual group A and B samples...

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