Identifying pharmaceutical manufacturing equipment's surface roughness and mitigating robustness concerns when using specular reflectance Fourier-transform infrared (FTIR) spectroscopy for rapid cleaning verification

Preventing cross-contamination during manufacturing is a regulatory requirement in the pharmaceutical manufacturing industry. One element of measures to prevent cross-contamination is the validation of cleaning processes for manufacturing equipment by assessing the surface contamination prior to manufacturing the next product. Several analytical techniques are used by the pharmaceutical industry, such as swab and rinse, followed by laboratory-based analytical techniques for analysis. While these are well-accepted techniques, a real-time analytical technique is a long-term desire by the industry. The FTIR technique is proven to be an effective measurement system for real-time analysis. However, in its early development, this technique requires many rigorous studies to implement in GMP manufacturing. In this study, the effect of the surface roughness, excipients, measurement distance, and the impact of the environmental temperature was investigated as part of the robustness testing as per the ICH guidelines. In addition, this investigation aimed to identify the surface roughness or surface type using the FTIR before the measurement and use the appropriate calibration model for the surface measurement. It was found that the FTIR could be used to identify the surface type and surface roughness of the pharmaceutical manufacturing equipment. This study also demonstrated that the surface finish# could impact the chemical prediction by approximately 28%. However, if the method described in this investigation is followed precisely, the FTIR would be capable of measuring surface cleanliness with a high degree of accuracy.