Development of an HPLC method for monitoring of Photofrin II therapy

Objectives: To develop and to validate a method to quantify plasma porphyrins after application of Photofrin II, a drug preparation that is used for photodynamic therapy (PDT) and as a radiosensitizer. Design and methods: After solid phase extraction of postdose plasma samples, reversed phase high performance-liquid chromatography with fluorescence detection was performed. Plasma porphyrin concentrations were monitored in five patients that were treated with Photofrin II. Results: The method proved linear over a wide concentration range, precise, and applicable in a routine clinical laboratory setting. Conclusions: The method described here will enable large-scale clinical pharmacokinetic studies on Photofrin II; investigations can now address possible correlations between individual concentrations of drug-derived plasma porphyrins and systemic photosensitivity—representing the main side effect of Photofrin II—with the perspective of individualized light protection regimens after Photofrin II administration.