In order to achieve local administration of drugs, calcein (CAL) encapsulated reverse phase evaporation vesicles (REV) carrying photoactive destabilization agent suprofen (SPF) in the lipid bilayer were prepared. Effect of both UV-A and UV-B photoactivation of liposomal membrane incorporated SPF on the destabilization of the liposome bilayer and the release of encapsulated CAL was investigated. Standard REV of phosphatidylcholine (PC):cholesterol (CHOL) in 7:3 molar ratio, and photoactive REV of PC:CHOL:SPF, and DPPC:CHOL:SPF in 7:33 molar ratio were prepared. CAL encapsulation efficiency (EE (%)) and in situ release was studied. SPF incorporation in the PC REV membrane led to approximately 5% increase in the EE (34%) in comparison to standard REV (29%). EE decreased (21%) when DPPC was used to replace PC. Exposure to UV-B caused the highest CAL release. The lowest release was from the unexposed REV DPPC led to a higher liposomal membrane stability (lower CAL release) than PC. A linear relationship was observed between UV-B exposure duration and REV permeability. This study revealed that membrane destabilization of SPF incorporated REV was best achieved upon photoactivation of the membrane-localized SPF by a 40 min exposure to UV-B. (C) 2004 Published by Elsevier B.V.