Preclinical studies with 5,10,15-Tris(4-methylpyridinium)-20-phenyl-[21H,23H]-porphine trichloride for the photodynamic treatment of superficial mycoses caused by Trichophyton rubrum.
Dermatophytes are fungi that cause infections of keratinized tissues. We have recently demonstrated the susceptibility of the dermatophyte Trichophyton rubrum to photodynamic treatment (PDT) with 5,10,15-Tris(4-methylpyridinium)-20-phenyl-[21H,23H]-porphine trichloride (Sylsens B) in 5 mm citric acid/sodium citrate buffer (pH 5.2, formulation I). In this work, we examined the penetration of Sylsens B in healthy and with T. rubrum infected skin and we investigated the susceptibility of T. rubrum to PDT using formulation I and UVA-1 radiation (340-550 nm). Skin penetration studies were performed with formulations I and II (Sylsens B in PBS, pH 7.4) applied on dermatomed skin, human stratum corneum (SC), disrupted SC by T. rubrum growth and SC pretreated with a detergent. No penetration was observed in healthy skin. Disruption of SC by preceding fungal growth caused Sylsens B penetration at pH 7.4, but not at pH 5.2. However, chemically damaged SC allowed Sylsens B to penetrate also at pH 5.2. UVA-1 PDT was applied ex vivo during two fungal growth stages of two T. rubrum strains (CBS 304.60 and a clinical isolate). Both strains could be killed by UVA-1 alone (40 J/cm(2)). Combined with formulation I (1 and 10 microm Sylsens B for, respectively, CBS 304.60 and the clinical isolate), only 18 J/cm(2) UVA-1 was required for fungal kill. Therefore, PDT with 10 microm Sylsens B (formulation I) and 18 J/cm(2) UVA-1 could be considered as effective and safe. This offers the possibility to perform clinical studies in future.
Smijs
Threes G M
TG
Leiden University Medical Centre, The Netherlands. G.M.T.Smijs@LUMC.nl
Pavel
Stan
S
Talebi
Mojgan
M
Bouwstra
Joke A
JA
D006801:Humans; D006863:Hydrogen-Ion Concentration; D009181:Mycoses / Q000188:drug therapy* / Q000382:microbiology; D010778:Photochemotherapy; D011166:Porphyrins / Q000627:therapeutic use*; D011726:Pyridinium Compounds / Q000627:therapeutic use*; D014249:Trichophyton / Q000472:pathogenicity*
C509254:5,10,15-tris(4-methylpyridinium)-20-phenyl-(21H,23H)-porphine; D011166:Porphyrins; D011726:Pyridinium Compounds