(131d) Chemical Imaging of Drug/Polymer in Polymer Films by Coherent Anti-Stokes Raman Scattering Microscopy

Noninvasive chemical imaging is most desirable for the study of drug distribution and release in the fields of pharmaceutics and biomaterials. Currently available imaging tools such as Fourier transform Infra-red (FTIR), Confocal Raman microscopy and secondary ion mass spectroscopy have limitations in sensitivity and speed. These limitations can be overcome by a recently developed new tool known as coherent anti-Stokes Raman (CARS) microscopy which has chemical selectivity, inherent three-dimensional (3D) resolution, high sensitivity and high speed. In addition, CARS microscopy can be combined with two-photon excitation florescence microscopy to obtain chemical mapping and fluorescence image at the same time. The combined image information as a complimentary tool allows the tracking several material in complicated systems. In addition, polarization of CARS provides the molecular orientation of each chemical composition which is useful for study of crystalline polymer. These unique properties of CARS present new ways of characterizing drug/polymer systems. CARS microscopy was used to study 3D drug distribution in various polymer matrices, in situ drug release, polarization of semi crystalline phase of polymer blends, drug mapping in microparticles and intracellular tracking of polymer micelles.