Synchrotron radiation-based Fourier-transform infrared spectromicroscopy for characterization of the protein/peptide distribution in single microspheres

The present study establishes a visualization method for the measurement of the distribution and localization of protein/peptide constituents within a single poly-lactide-co-glycolide (PLGA) microsphere using synchrotron radiation based Fourier-transform infrared speciiomlcroscopy (SR-FTIR). The representative infrared wavenumbers specific for protein/peptide (Exenatide) and excipient (PLGA) were identified and chemical maps at the single microsphere level were generated by measuring and plotting the intensity of these specific bands. For quantitative analysis of the distribution within microspheres, Matlab soft are was used to transform the map file into a 3D matrix and the matiix values specific for the drug and excipient were extracted. Comparison of the normalized SR- FM maps of PLGA and Exenatide indicated that PLGA was unit-on-lily distributed, while Exenatide was relatively non-uniformly distributed in the microspheres. In conclusion, SR-FTIR is a rapid, nondestructive and sensitive detection technology to provide the distribution of chemical constituents and functional groups in microparticles and microspheres. (C) 2015 Chinese Pharmaceutical Association and Institute of Materia 'Medico, Chinese Academy of 'Medical Sciences. Production and hosting by Elsevier B.V.