Presentation on theme: "PORFIRINAS E APLICAÇÕES BIOLÓGICAS Departamento de Química, Universidade de Aveiro José A. S. Cavaleiro."— Presentation transcript:
PORFIRINAS E APLICAÇÕES BIOLÓGICAS Departamento de Química, Universidade de Aveiro José A. S. Cavaleiro
Complex mixture of haematoporphyrin oligomers (dimers – hexamers) Photofrin
Photosensitisers’ medicinal applications 1 2 5 3 1 O 2 3 O 2 6 1 – Light absorption 2 - Fluorescence 3 – Internal conversion 4 – Intersystem Crossing, ISC 5 - Phosphorescence 6 - Type II Mechanism 7 - Type I Mechanism 7 Radical or ions radicals Energy o S S 1 S 2 S n 4 T 1 Modified Jablonski Diagram
1867, Thudichum 1910, Hausmann 1913, Meyer-Betz 1924, Policard 1942, Auler and Banzer Fluorescence properties of haematoporphyrin (Hp) Effect of Hp and light on red blood cells; skin reactions in mice exposed to light after Hp administration (photosensitivity, phototoxicity) 1 st report of human photosensitization by porphyrins (he injected himself with 200 mg of Hp; subsequently noticed prolonged pain and swelling in light-exposed areas) 1 st report of fluorescent porphyrin localization in a malignant tumour (he observed the Hp red fluorescence in a rat sarcoma illuminated with UV light) Localization and fluorescence of exogenously administrated porphyrins in malignant tumours
1948, Figge and Weiland 1951, Manganiello and Figge 1955, Figge et al. Tumour localizing properties of porphyrins and application in the diagnosis and treatment of tumours. 240 mice with induced and transplanted tumours 50 non-tumours bearing mice Porphyrin localization in each tumour-type; fluorescence within 24-28h of administration; 10-14 days persistence. Hp effects in 3 patients with head and neck malignancies (no fluorescence detected; lower doses in humans – 30-120 mg) Intravenous administration of Hp dihydrochloride to patients before excision of variety of benign and malignant lesions. Fluorescence was observed and increased in proportion to Hp dose. Higher doses allowed a breast cancer detection.
1955, Peck Hp fluorescence in biliary and bladder systems (in animals and humans); with a high dosage (1000 mg) one patient exhibited fluorescence in a cervical carcinoma Hp can play a role as a diagnostic tool for cancer But... a major disadvantage was the large dose of photosensitiser, which led to phototoxicity.
1955, Schwartz 1960, Lipson Used Hp was a mixture of porphyrins; after purification, “pure” Hp localized poorly in tumours, but residue left behind showed great affinity for tumours tissues. Hp derivative (HpD) described. Hp-dihydrochloride + sulphuric /acetic acid, precipitation with sodium acetate. The precipitated + NaOH and pH adjusted to 7.4.
1976, Kelly The 1 st published account of clinical PDT with HpD human bladder tumour cells transplanted into mice could be destroyed using PDT 1978, Dougherty The 1 st extensive clinical survey with HpD 25 patients with cutaneous or sub-cutaneous malignancies 1993 Canadian authorities granted the 1 st regulatory approval (bladder, oesophagus) for cancer PDT using Photofrin (commercialised by QLT Phototherapeutics, Vancouver) France (oesophagus, bladder); Germany (lung); Japan (lung, oesophagus, stomach, cervix); Netherlands (lung, oesophagus); USA (oesophagus, lung) Subsequent approvals: