Visualization of bioavailable liposomal doxorubicin using a non-perturbingconfocal imaging technique

\Commonly employed tissue processing techniques can significantly alter tis sue drug distribution patterns for liposomal encapsulated drugs by virtue o f drug leakage via loss of membrane integrity. We report here a method that has been developed to determine the fluorescence of bioavailable doxorubic in (DOX) in tissues after administration of liposomal DOX formulations. A n on-perturbing confocal fluorescence microscopy (CFM) technique with image p rocessing analysis was used with unprocessed fresh tissues. This method tak es advantage of the fact that considerable quenching occurs when DOX is wit hin liposomes, leading to the selective visualization of the fluorescence d ue to DOX released from liposomes. We demonstrate that fresh tissue confoca l imaging can be applied to provide detailed drug distribution information with improved accuracy and is a superior method for analyzing tissue distri bution of liposome entrapped fluorescent agents.