Coherent anti-stokes raman scattering microscopy to monitor drug dissolution in different oral pharmaceutical tablets

Coherent anti-Stokes Raman scattering (CARS) microscopy is used to visualize the release of a model drug (theophylline) from a lipid (tripalmitin) based tablet during dissolution. The effects of transformation and dissolution of the drug are imaged in real time. This study reveals that the manufacturing process causes significant differences in the release process: tablets prepared from powder show formation of theophylline monohydrate on the surface which prevents a controlled drug release, whereas solid lipid extrudates did not show formation of monohydrate. This visualization technique can aid future tablet design.