Clinical pharmacokinetics of protoporphyrin IX (PpIX) in condylomata acuminata patients: ex vivo fluorescence examination

Objectives: To investigate the pharmacokinetics of ALA induced protoporphyrin IX (PpIX) in lesions of urethral condylomata acuminata. Methods: Sixty patients (20 - 60 years old, 48 male and 12 female) with urethral condylomata acuminata were divided randomly into 5 groups to receive different concentrations of ALA solution (0.5, 1, 3, 5 or 10%). The ALA solution was applied topically to the lesion for a different length of time (1, 3, 5 or 7 h). Biopsy was performed at the end of incubation and specimens were subjected to histological and PpIX fluorescence analyses. Results: ALA-induced PpIX fluorescence was dominantly distributed in the epidermis. The maximal fluorescence intensity was detected at the 5 h of incubation. Higher ALA concentration (e.g. 5 and 10%) produced stronger intensity. In contrast, only the minimal amount of PpIX fluorescence was detected in the dermis. Conclusions: The results suggest that the topical application of 5 - 10% ALA solution for 3-5 h are the optimal conditions for ALA/PpIX-mediated photodynamic therapy for the treatment of urethral condylomata acuminata.