Tumor selectivity at short times following systemic administration of a liposomal temoporfin formulation in a murine tumor model.
Meso-tetra(hydroxyphenyl)chlorin (mTHPC) (INN: Temoporfin) is one of the most potent photodynamically active substances in clinical use. Treatment protocols for Temoporfin-mediated photodynamic therapy often rely on drug-light intervals of several days in order for the photosensitizer to accumulate within the target tissue, though tumor selectivity is limited. Here, the mTHPC localization was studied at 2-8 h following systemic administration of a liposomal Temoporfin formulation (0.15 mg kg(-1) b.w.) in HT29 human colon adenocarcinoma in NMRI nu/nu mice. Photosensitizer distribution within tumor and internal organs was investigated by means of high performance liquid chromatography following chemical extraction, as well as in situ fluorescence imaging and point-monitoring fluorescence spectroscopy. For tumor tissue, the Temoporfin concentrations at 4 h (0.16+/-0.024 ng mg(-1)) and 8 h (0.18+/-0.064 ng mg(-1)) were significantly higher than at 2 h (0.08+/-0.026 ng mg(-1)). The average tumor-to-muscle and the tumor-to-skin selectivity were 6.6 and 2, respectively, and did not vary significantly with time after photosensitizer injection. In plasma, the Temoporfin concentration was low (0.07+/-0.07 ng mg(-1)) and showed no significant variation with time. Our results indicate a rapid biodistribution and clearance from the bloodstream. Within the same type of organ, data from both fluorescence methods generally exhibited a significant correlation with the extraction results.
Svensson
Jenny
J
Department of Physics, Lund University, and Department of Dermatology, Lund University Hospital, Lund, Sweden. jenny.svensson@fysik.lth.se
Johansson
Ann
A
Gräfe
Susanna
S
Gitter
Burkhard
B
Trebst
Tilmann
T
Bendsoe
Niels
N
Andersson-Engels
Stefan
S
Svanberg
Katarina
K
D000230:Adenocarcinoma / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003110:Colonic Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D004195:Disease Models, Animal; D019073:HT29 Cells; D006801:Humans; D008081:Liposomes; D008652:Mesoporphyrins / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000627:therapeutic use; D051379:Mice; D009368:Neoplasm Transplantation; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000627:therapeutic use; D013050:Spectrometry, Fluorescence
D008081:Liposomes; D008652:Mesoporphyrins; D017319:Photosensitizing Agents; C072269:temoporfin