• Photosensitizer: Haematoporphyrin-derivative
  • Tradename: Photofrin®
  • Company Photosensitizer: QLT PhotoTherapeutics
  • Clinical Application: Oesophageal, lung, bladder, gastric and cervical cancer, cervical dysplasia
  • Wavelength (nm): 630
  • Extinction Coefficient (M-1 cm-1): 3.03 103
  • Mode of Delivery: Intravenous or topical
  • Delivery vehicle: 5% Dextrose
  • Typical Dose (mg kg-1): 2.0–5.0
  • Light Dose (J cm-2): 100–200
  • Time Post-Injection: 24–48 h
  • Duration of Skin Photosensitivity: 2–3 months

The first generation photosensitizers are haematoporphyrin derivatives[64] such as Photofrin® and are the most commonly used photosensitizers. Haematoporphyrin derivatives were originally synthesized[65] by combining haematoporphyrin with 5% sulphuric acid in acetic acid at room temperature.

Subsequently, the mixture was treated with an aqueous base and then neutralized. This led to the formation of a complex mixture of dimers and oligomers primarily involving ester and ether linkages[66]. Partial purification of the most active of these oligomers by highperformance liquid chromatography (HPLC) or sizeexclusion gel chromatography lead to Photofrin, 90–95% of which is the active component[67].

Photofrin is marketed by QLT PhotoTherapeutics (Vancouver, Canada) and has been accepted in the clinic in several countries for the treatment of early- and latestage lung cancer, superficial and advanced oesophageal cancer, bladder cancer, superficial and early-stage gastric cancers, early stage cervical cancer and cervical dysplasia (a precancerous condition)[68]. In addition, Photofrin is being investigated as a possible therapy against Karposi’s sarcoma, cancers of the head and neck, brain, intestine, lung, breast and skin (both primary and metastatic breast cancers), as well as urinary bladder, abdominal and thoracic cancers. Other conditions include Barrett’s oesophagus, psoriasis and arterial restenosis[69], and all of these conditions are being investigated in clinical trials with mostly promising results. Derivations of Photofrin are also being used.

For example, Photoheme is produced in Russia and has been accepted by the Pharmacological Committee of Russia for a wide range of clinical uses including skin, breast, oropharingeal, lung, larynx and gastrointestinal cancers, as well as psoriasis and prophylaxis for corneal transplant opacity and recurrent blindness[70].