Evaluation of catheter-induced tribological damage to porcine aorta using infra-red spectroscopy

© 2016 Elsevier Ltd Studies were carried out to assess the potential of attenuated total internal reflection Fourier transform infrared (ATR)-FTIR spectroscopy as a tool for evaluating mechanical-tribological damage to the blood vessel wall occurring during simulated endovascular catheterization on fresh ex-vivo porcine aortic tissue. It is envisaged that this method could be used in laboratory tests to quantitatively compare catheters or catheterization approaches with regard to their effect on damage to the aorta wall. Tribological damage was induced on the tissue. Obvious changes were visible in the FTIR spectra as well as the friction coefficient as a function of increasing damage. In particular, the spectral changes due to damage to the outermost layer of the tissue were significant, provided appropriate sample conditioning was performed. These changes, which correlated with a reduction in friction coefficient, can be attributed to the removal of successive layers of tissue as a result of a wear process. In conclusion, FTIR spectroscopy was found to be a reliable and effective measurement technique for quantifying catheter-induced tissue damage, allowing very repeatable spectra to be obtained from the tissue up to 36 h after excision with no major spectral changes observed during this time frame due to tissue age

Assessment of diffuse transmission mode in near-infrared quantification--part I : The press effect on low-dose pharmaceutical tablets

Quantitative applications for pharmaceutical solid dosage forms using near-infrared (NIR) spectroscopy are central to process analytical technology (PAT) manufacturing designs. A series of studies were conducted to evaluate the use of NIR transmission mode under various pharmaceutical settings. The spectral variability in relation to tablet physical parameters were investigated using placebo tablets with different thickness and porosity steps and both variables showed an exponential relationship with the detected transmittance signal drop. The drug content of 2.5% m/m folic acid tablets produced under extremely different compaction conditions was predicted and found to agree with UV assay results after inclusion of extreme physical outliers to the training sets. NIR transmission was also shown to traverse a wide section of the tablet by comparing relative blocking intensities from different regions of the tablet surface and <90% of the signal was detected through a central area of 7 mm diameters of the tablet surface. NIR Quantification of both film thickness and active ingredient for film-coated tablets are examined in part II of this study