Original data accompanying the publication in the Journal of Pharmaceutical Sciences of “Quantifying pharmaceutical film coating with optical coherence tomography and terahertz pulsed imaging: an evaluation”

Figure 1 - Schematic of an in-house SD-OCT system with a tablet placed on a X-Y translation stage. SLD - superluminescent diode L1, L2 – achromatic doublet, f=30mm. L3 - achromatics doublet, f=50mm. BS - 50:50 beam splitter. The system acquired 100 x 100 B-scans, one of which is shown (b) with the tablet central region annotated by the dashed line and the respective A-scan with the interfaces annotated by the respective arrows shown (c).

Figure 2 - Data processing algorithm for automatically quantifying coatings on pharmaceutical tablets based on OCT measurements.

Figure 3 - Examples of the raw A-scans and the wavelet denoised A-scans with decomposition levels of 2 and 5 for coating thicknesses 70 (a, b) and 140 µm (c, d) respectively.

Figure 4 - B-scans for tablets with coating thicknesses of 70 µm (a) and 140 µm (b) respectively, where the air-coating and coating-core interfaces are curve-fitted using the peaks identified from the wavelet denoised A-scans.

Figure 5 - Examples of coating thickness measurements extracted with the standard peak finding approach by means of simple thresholding and our proposed algorithm for A-scans at several example points on the OCT map for coating thicknesses 70 (a) and 140 µm (b) respectively.

Figure 6 – Comparison of the pharmaceutical tablet coating thicknesses measured using TPI and OCT, where the OCT measurements are quantified by manual visual inspection and the proposed automated algorithm using the same refractive index as TPI in (a) and (b) and with the estimated refractive index (c) and (d) for the top and bottom surface of the bi-convex tablet respectively. Lines are plotted to guide the eye.

Figure 7 - Comparison of the intra-tablet coating thickness distribution measured using TPI and OCT for one of the surfaces of the bi-convex tablet.

Figure 8 - Comparison of the intra-tablet variability as measured using TPI and OCT for the bi-convex tablet.