“Chemical Photography” of Drug Release

The enhanced chemical visualization of FTIR spectroscopic imaging combined with the macro-ATR−IR approach has allowed us to study polymer/drug formulations in contact with aqueous solution as a function of time. This imaging method enabled the analysis of both the drug and polymer distribution via their corresponding IR bands. The evolution of these images as a function of time was studied to reveal the mechanism of drug release. This method allowed us, for the first time, to spectroscopially image the crystallization of ibuprofen molecularly dispersed in poly(ethylene glycol) (PEG) during the dissolution process in water. The imaging of dissolution of inclusion complexes of the drug in cyclodextrin has shown that this can prevent drug crystallization and enhances dissolution. This FTIR imaging approach has considerable potential for revealing the underlying principles of controlled drug release processes from many pharmaceutical formulations.