Partial characterization of different mixtures of solids by measuring the optical nonlinear response
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Partial characterization of different mixtures of solids by measuring the optical nonlinear response. / Strachan, Clare J; Lee, Chris J; Rades, Thomas.
In: Journal of Pharmaceutical Sciences, Vol. 93, No. 3, 03.2004, p. 733-42.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Partial characterization of different mixtures of solids by measuring the optical nonlinear response
AU - Strachan, Clare J
AU - Lee, Chris J
AU - Rades, Thomas
N1 - Copyright 2004 Wiley-Liss, Inc. and the American Pharmacists Association
PY - 2004/3
Y1 - 2004/3
N2 - We report on the theoretical basis and first experimental results of a new method based on optical nonlinearity, for characterising crystallinity and polymorphism of pharmaceuticals in the solid state. Once the theoretical basis of optical nonlinearity of crystalline structures is established, a new and rapid method based on this physical theory can be developed to quantitatively determine polymorphism or crystallinity. An apparatus was set up to measure the second harmonic response of powdered samples when irradiated with a pulsed laser source. The response of quartz-glass, enalapril maleate forms I-II and enalapril maleate form II-PVP mixtures were measured and modeled. It was found that the quartz-glass system showed high sensitivity to the presence of quartz and was well predicted by our theoretical model. The response of enalapril maleate polymorph mixtures was also sensitive to changes in the polymorph ratio. The theoretical predictions of the polymorph mixtures agreed quantitatively with the experimental results. The response of enalapril maleate form II-PVP mixtures agreed quantitatively with the physical model and showed extremely low noise and high sensitivity, giving very promising limits of detection (LOD) and quantification (LOQ) of 0.12 and 0.41%, respectively. This rapid, novel technique has potential for industrial monitoring of pharmaceutical manufacturing processes.
AB - We report on the theoretical basis and first experimental results of a new method based on optical nonlinearity, for characterising crystallinity and polymorphism of pharmaceuticals in the solid state. Once the theoretical basis of optical nonlinearity of crystalline structures is established, a new and rapid method based on this physical theory can be developed to quantitatively determine polymorphism or crystallinity. An apparatus was set up to measure the second harmonic response of powdered samples when irradiated with a pulsed laser source. The response of quartz-glass, enalapril maleate forms I-II and enalapril maleate form II-PVP mixtures were measured and modeled. It was found that the quartz-glass system showed high sensitivity to the presence of quartz and was well predicted by our theoretical model. The response of enalapril maleate polymorph mixtures was also sensitive to changes in the polymorph ratio. The theoretical predictions of the polymorph mixtures agreed quantitatively with the experimental results. The response of enalapril maleate form II-PVP mixtures agreed quantitatively with the physical model and showed extremely low noise and high sensitivity, giving very promising limits of detection (LOD) and quantification (LOQ) of 0.12 and 0.41%, respectively. This rapid, novel technique has potential for industrial monitoring of pharmaceutical manufacturing processes.
KW - Electrochemistry
KW - Nonlinear Dynamics
KW - Optics and Photonics
KW - Particle Size
KW - Pharmaceutical Preparations
U2 - 10.1002/jps.10535
DO - 10.1002/jps.10535
M3 - Journal article
C2 - 14762911
VL - 93
SP - 733
EP - 742
JO - Journal of Pharmaceutical Sciences
JF - Journal of Pharmaceutical Sciences
SN - 0022-3549
IS - 3
ER -
ID: 46408772