title: Assessment of drug entrapment within liposomes using photophysical probes.
abstract: The photophysical and photochemical behavior of (R)-cinacalcet (CIN) and (S)-naproxen (NPX) entrapped within liposomes has been studied. For this purpose, liposome encapsulated drugs have been prepared through thin layer evaporation and characterized by transmission electron microscopy, cryoscopy scanning electron microscopy and dynamic light scattering. Steady state and time-resolved fluorescence experiments showed similar spectra, emission quantum yields, singlet energies and lifetimes for the selected drugs, outside and inside liposomes. By contrast, laser flash photolysis experiments revealed an important enhancement of the triplet lifetimes for entrapped drugs inside liposomes, indicating the spatial confinement existing in the microenvironment prevailing in these biomimetic entities. Thus, this photophysical property shows potential as a non-invasive, direct and valuable tool to monitor encapsulation of photoactive drugs and to probe the intraliposome environment. In addition, it provides a new quantitative indicator of the capability of liposomes to act as drug carriers.
authors: Instituto de Tecnología Química (UPV-CSIC), Universitat Politècnica de València, Consejo Superior de Investigaciones Científicas, Valencia, Spain; Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy.
authors: Filomena
authors: F
authors: Oliverio
authors: Instituto de Tecnología Química (UPV-CSIC), Universitat Politècnica de València, Consejo Superior de Investigaciones Científicas, Valencia, Spain.
authors: Edurne
authors: E
authors: Nuin
authors: Unidad Mixta de Investigación IIS La Fe-UPV, Hospital La Fe, Valencia, Spain.
authors: Inmaculada
authors: I
authors: Andreu
authors: Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy. Electronic address: gaetano.ragno@unical.it.
authors: Gaetano
authors: G
authors: Ragno
authors: Instituto de Tecnología Química (UPV-CSIC), Universitat Politècnica de València, Consejo Superior de Investigaciones Científicas, Valencia, Spain. Electronic address: mmiranda@qim.upv.es.
authors: Miguel A
authors: MA
authors: Miranda
mesh_terms: D004337:Drug Carriers; D008081:Liposomes; D015335:Molecular Probes; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D004337:Drug Carriers; D008081:Liposomes; D015335:Molecular Probes
keywords: Cinacalcet; Drug carrier; Drug delivery; Fluorescence; Laser flash photolysis; Liposome; Naphthalene chromophore; Naproxen; Singlet excited states; Triplet excited states