IJUP08 - Universidade do Porto

Determination of physical parameters in pharmaceutical powders
by near infrared spectroscopy (NIR)
Ana Cruz 1,2 , Sandra Soares 1,2 , Mafalda C. Sarraguça 1 , Paulo C. Costa 2 , Helena R.
Amaral 2 , João A. Lopes 1
1 Serviço de Química-Física, Faculdade de Farmácia, Universidade do Porto, Portugal
2 Serviço de Tecnologia Farmacêutica, Faculdade de Farmácia, Universidade do Porto, Portugal
Near infrared spectroscopy (NIR) can be used to determine physical and chemical
parameters in solids, powders and liquids [1]. The application of this spectroscopic
technique in the pharmaceutical industry is increasing [2]. NIR has been successfully
applied for variability reduction in primary and secondary pharmaceutical production while
as a research and quality control technique [3]. In the field of physical parameters
determination, NIR spectroscopy is still underused. Parameters such as particle size,
apparent volume and flowability, are defined by the Portuguese Pharmacopeia as some of
the tests performed to characterize pharmaceutical powders. These tests require specific
equipment and are time consuming. NIR spectroscopy can be used to determine these
parameters, with the advantage of being a fast and low-cost technique.
To establish the potential of the spectroscopic technique in the determination of some
important physical parameters, a series of tests were performed in powder samples. The
parameters determined were the angle of rest, apparent volume, and flowability. The tests
were executed as determined in the pharmacopeia. The samples used were blended
powders based on a pharmaceutical formulation of acetaminophen (as the active
ingredient) and three excipients (microcrystalline cellulose, talc and magnesium stearate).
The NIR spectrum was recorded on a Fourier Transform NIR analyzer in reflectance mode.
Partial least squares (PLS) calibrations were optimized in terms of latent variables with
cross-validation [4]. The NIR results were compared with the reference methods results
and the performance of the NIR was accessed.
References
[1] Burns, D.A. and Ciurczak, E.W. (2001) Handbook of Near-Infrared Analysis, Marcel Dekker,
2 nd Edition, New York.
[2] Blanco, M. Coello, J., Iturriaga, H., Maspoch, S. and Pezuela, C.(1998) Near-Infrared
Spectroscopy in the Pharmaceutical Industry, Analyst, 123, 135R.
[3] Lopes, J.A., Costa, P.F., Alves, T.P. and Menezes, J.C. (2004) Chemometrics in Bioprocess
Engineering: Process Analytical Technology (PAT) Applications, Chemom. Intell. Lab. Syst., 74,
269.
[4] Martens, H. and Næs, T. (1989) Multivariate Calibration, John Wiley & Sons, Chicester.
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