Association of acenaphthoporphyrins with liposomes for the photodynamic treatment of leishmaniasis.
Acenaphthoporphyrins are potential photosensitizers for photodynamic therapy, but their hydrophobicity limits their potential. Liposomes have been widely investigated as delivery vehicles that can transport hydrophobic drugs in biological systems. Here we study the association of acenaphthoporphyrins with liposomes made up of dimyristoyl phosphatidylcholine (DMPC), and to liposomes made up of a mixture of DMPC, cholesterol (Chol) and distearoyl phosphatidylglycerol (DSPG) in a 2:1:0.8 molar ratio to evaluate how liposome composition affects association constants. In liposomes consisting only of DMPC, the smaller monoacenaphthoporphyrin had the largest association constant of 5.5 x 10(4) m(-1) while the larger adj-diacenaphthoporphyrin and opp-diacenaphthoporphyrin (ODP) had smaller association constants at 1.8 x 10(4) and 1.5 x 10(4) m(-1), respectively. The addition of liposomal Chol and DSPG has little effect on the magnitudes of the association constants. Polarization studies show that the acenaphthoporphyrins are driven far into the lipid bilayer to minimize polar-nonpolar interactions. Confocal microscopy confirms that the DMPC liposomes transport the porphyrins into promastigotes of Leishmania tarentolae. The compounds associated with DMPC:Chol:DSPG liposomes are effective in vitro against axenic and intracellular amastigotes of the pathogenic Leishmania panamensis. The effectiveness of the compounds is enhanced upon exposure of cultures to visible light.
Gardner
Daniel M
DM
Department of Chemistry, Illinois State University, Normal, IL, USA.
Taylor
Viviana M
VM
Cedeño
David L
DL
Padhee
Shruti
S
Robledo
Sara M
SM
Jones
Marjorie A
MA
Lash
Timothy D
TD
Vélez
Iván D
ID
D000073:Acenaphthenes; D002462:Cell Membrane / Q000378:metabolism; D004337:Drug Carriers / Q000737:chemistry*; D007896:Leishmaniasis / Q000628:therapy*; D008081:Liposomes / Q000737:chemistry* / Q000493:pharmacokinetics / Q000627:therapeutic use; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage; D011166:Porphyrins / Q000008:administration & dosage* / Q000737:chemistry / Q000627:therapeutic use
D000073:Acenaphthenes; D004337:Drug Carriers; D008081:Liposomes; D017319:Photosensitizing Agents; D011166:Porphyrins