TY - JOUR
T1 - How to measure coating thickness of tablets
T2 - Method comparison of optical coherence tomography, near-infrared spectroscopy and weight-, height- and diameter gain
AU - Wahl, P. R.
AU - Peter, A.
AU - Wolfgang, M.
AU - Khinast, J. G.
PY - 2019/9/1
Y1 - 2019/9/1
N2 - Film coating of pharmaceutical dosage forms, such as tablets and pellets, can be used to tailor the drug release profile. With that regard, a uniform coating thickness of a single tablet (intra-tablet), all tablets (inter-tablet) and subsequent batches (inter-batch) is crucial. We present a method comparison between in-line (optical coherence tomography and near-infrared spectroscopy) and well-established off-line (height-, weight- and diameter-gain) approaches to determining the coating thickness of tablets. We used single tablets drawn during a commercial coating process. Comparing the low intra- and high inter-tablet coating variability indicated that the tablets had a broad distribution of spray zone passes but at a random tablet orientation. Even at the end of the coating process at a mean coating thickness of about 70 µm, the inter-tablet standard deviation was about 9 µm or 13% relative standard deviation. Determining correlations between the methods identified the factors that contribute to the measurement uncertainty and bias for each method. Ultimately, we aimed to establish that in-line methods match or even surpass the conventional off-line reference methods in terms of accuracy and precision of coating thickness measurement.
AB - Film coating of pharmaceutical dosage forms, such as tablets and pellets, can be used to tailor the drug release profile. With that regard, a uniform coating thickness of a single tablet (intra-tablet), all tablets (inter-tablet) and subsequent batches (inter-batch) is crucial. We present a method comparison between in-line (optical coherence tomography and near-infrared spectroscopy) and well-established off-line (height-, weight- and diameter-gain) approaches to determining the coating thickness of tablets. We used single tablets drawn during a commercial coating process. Comparing the low intra- and high inter-tablet coating variability indicated that the tablets had a broad distribution of spray zone passes but at a random tablet orientation. Even at the end of the coating process at a mean coating thickness of about 70 µm, the inter-tablet standard deviation was about 9 µm or 13% relative standard deviation. Determining correlations between the methods identified the factors that contribute to the measurement uncertainty and bias for each method. Ultimately, we aimed to establish that in-line methods match or even surpass the conventional off-line reference methods in terms of accuracy and precision of coating thickness measurement.
KW - Coating variability
KW - Film coating
KW - Near-infrared spectroscopy (NIR)
KW - Optical coherence tomography (OCT)
KW - Process analytical technology (PAT)
UR - http://www.scopus.com/inward/record.url?scp=85068936385&partnerID=8YFLogxK
U2 - 10.1016/j.ejpb.2019.06.021
DO - 10.1016/j.ejpb.2019.06.021
M3 - Article
C2 - 31271890
AN - SCOPUS:85068936385
SN - 0939-6411
VL - 142
SP - 344
EP - 352
JO - European Journal of Pharmaceutics and Biopharmaceutics
JF - European Journal of Pharmaceutics and Biopharmaceutics
ER -