DRUG-DELIVERY WITH MICROSECOND LASER-PULSES INTO GELATIN

Photoacoustic drug delivery is a technique for localized drug delivery by laser-induced hydrodynamic pressure following cavitation bubble ex pansion and collapse. Photoacoustic drug delivery was investigated on gelatin-based thrombus models with planar and cylindrical geometries b y use of one microsecond laser pulses. Solutions of a hydrophobic dye in mineral oil permitted monitoring of delivered colored oil into clea r gelatin-based thrombus models. Cavitation bubble development and pho toacoustic drug delivery were visualized with flash photography. This study demonstrated that cavitation is the governing mechanism for phot oacoustic drug delivery, and the deepest penetration of colored oil in gels followed the bubble collapse. Spatial distribution measurements revealed that colored oil could be driven a few millimeters into the g els in both axial and radial directions, and the penetration was less than 500 mu m when the gelatin structure was not fractured. (C) 1996 O ptical Society of America