Transmission Raman spectroscopy as a tool for quantifying polymorphic content of pharmaceutical formulations.
We present the first quantitative study of polymorphic content in a model pharmaceutical formulation using transmission Raman spectroscopy (TRS), and compare the results obtained with those from traditional backscattering geometry. The transmission method is shown to provide a true bulk measurement of the composition, being unaffected by systematic or stochastic sub-sampling issues that can plague traditional backscattering geometries. The accuracy of the quantification of the polymorphs using TRS was shown to surpass considerably that achieved using conventional backscattering mode. For a model-free fit, the TRS method yielded R(2) of 0.996 compared to the backscattering value of 0.802; for a partial least squares fit with a single component the TRS method accounted for 98.09% of the variance in the data and yielded an R(2) of 0.985, compared to 89.65% of the variance and R(2) of 0.804 for the backscattering method.
Aina
Adeyinka
A
School of Pharmacy, Boots Science Building, University of Nottingham, NG7 2RD, UK.
Hargreaves
Michael D
MD
Matousek
Pavel
P
Burley
Jonathan C
JC
D000893:Anti-Inflammatory Agents / Q000737:chemistry; D003460:Crystallization; D004339:Drug Compounding; D005439:Flufenamic Acid / Q000737:chemistry; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*
D000893:Anti-Inflammatory Agents; D004364:Pharmaceutical Preparations; D005439:Flufenamic Acid