temoporfin temoporfin temoporfin (inn) is a photosensitizer (based on chlorin) used in photodynamic therapy for the treatment of squamous cell carcinoma of the head and neck . it is marketed in the european union under the brand name foscan. the u.s. food and drug administration (fda) declined to approve foscan in 2000. the eu approved its use in june 2001. temoporfinclinical dataahfs/drugs.cominternational drug nameslicense data eu ema: by inn atc codel01xd05 (who) legal statuslegal status in general: ℞ (prescription only) identifiers iupac name 3,3',3'',3'''-(2,3-dihydroporphyrin-5,10,15,20-tetrayl)tetraphenol cas number122341-38-2 ypubchem cid60751chemspider54754uniifu21s769pfkeggd06066 ychemblchembl383675comptox dashboard (epa)dtxsid7048619 echa infocard100.152.970 chemical and physical dataformulac44h32n4o4molar mass680.764 g·mol−13d model (jsmol)interactive image smiles c1cc2=nc1=c(c3=cc=c(n3)c(=c4c=cc(=n4)c(=c5c=cc(=c2c6=cc(=cc=c6)o)n5)c7=cc(=cc=c7)o)c8=cc(=cc=c8)o)c9=cc(=cc=c9)o inchi inchi=1s/c44h32n4o4/c49-29-9-1-5-25(21-29)41-33-13-15-35(45-33)42(26-6-2-10-30(50)22-26)37-17-19-39(47-37)44(28-8-4-12-32(52)24-28)40-20-18-38(48-40)43(36-16-14-34(41)46-36)27-7-3-11-31(51)23-27/h1-17,19,21-24,46-47,49-52h,18,20h2/b41-33-,41-34-,42-35-,42-37-,43-36-,43-38-,44-39-,44-40-key:lypfdbrunkhdgx-lwqdqpmzsa-n (verify) good results were obtained in 21 of 35 patients treated in germany. it is photoactivated at 652 nm i.e. by red light. patients can remain photosensitive for several weeks after treatment.