Figure 10 shows the NIR predicted CPM concentrations versus the HPLC results for each tablet in the calibration set. One tablet was left out of the calibration set at each level for
prediction-model validation. Figure 11 shows the NIR predictions of the validation set versus the HPLC results for CPM on each tablet.
Better precision and accuracy can be achieved with a training set designed with smaller increments around the target label
claim. Tablets from on-line press processing can be scanned and sent to the laboratory for HPLC analysis and selected for
calibration samples to cover the range using a few extra pilot-batch samples needed to extend the range to ±15% of label claim.
Near-infrared assay and content uniformity of tablets provides a fast, accurate means of monitoring tablets for production
that is in step with the US Food and Drug Administration's process analytical technology initiative. The data show promising
results that could relieve laboratory workload of high-performance liquid chromatography analysis and bring analysis closer
to "real time" for process monitoring. Ten tablets can be analyzed in <5 min. The software provided with the instrument is
used for data collection and developing prediction models. The software also provides dedicated routine analysis methods for
content-uniformity analysis yielding results in percent label claim and percent relative standard deviation as well as pass–fail
The average repeatability result for five different tablets measured 10 times of nominal 0.1-mg chlorpheniramine maleate was
0.0039 with a bias of 0.0018. The repeatability result for 5 tablets of 0.5 mg chlorpheniramine maleate was 0.0055 with a
bias of 0.0057. Better precision and accuracy can be achieved with a training set designed with smaller increments around
the target label claim.
Robert Mattes* is an applications scientist at FOSS NIRSystems, Inc., 7703 Montpelier Rd., Laurel, MD 20723 tel. 301.680.7251, fax 301.236.0134,
and Denise Root is a marketing manager at FOSS NIRSystems. Om Anand, Maria Gerald Rajan, Namrata R. Trivedi, and Wen Qu are graduate students, and Yingxu Peng, PhD, and Yichun Sun, PhD, are postdoctorate fellows, Department of Pharmaceutical Sciences, University of Tennessee, Memphis, TN.
*To whom all correspondence should be addressed.
Submitted: Nov. 11, 2006. Accepted: Jan. 17, 2007.
Key words: content uniformity, near-infrared, process analytical technology
1. Handbook of Near-Infrared Analysis, D.A. Burns and E.W. Ciuczak, Eds.(Marcel Dekker, Inc., New York, NY, 2001).