title: Nanoscale mid-infrared imaging of phase separation in a drug-polymer blend.
abstract: The applicability of nanoscale mid-infrared (mid-IR) spectroscopy for the study of the micro- and nanostructure of pharmaceutical drug-polymer systems was explored. Felodipine-poly(acrylic acid) (PAA) blends were used as model systems. Standard atomic force microscopy evaluation as a function of drug-polymer composition suggested limited miscibility, in line with previous findings. Localized spectra on a 50:50 (w/w) felodipine-PAA dispersion revealed that the discrete submicrometer domains formed corresponded to an amorphous felodipine-rich phase while the continuous phase tended to be rich in PAA. Further, spectroscopic imaging at selected wavenumbers, enabling discrimination between both constituents, confirmed this finding and made it possible to chemically image differences in composition between each phase with submicrometer resolution.
authors.affiliation: Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Bernard
authors.initials: B
authors.lastname: Van Eerdenbrugh
authors.forename: Michael
authors.initials: M
authors.lastname: Lo
authors.forename: Kevin
authors.initials: K
authors.lastname: Kjoller
authors.forename: Curtis
authors.initials: C
authors.lastname: Marcott
authors.forename: Lynne S
authors.initials: LS
authors.lastname: Taylor
mesh_terms: D018625:Microscopy, Atomic Force; D036103:Nanotechnology; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D013055:Spectrophotometry, Infrared
chemical_list: D004364:Pharmaceutical Preparations; D011108:Polymers