Verteporfin

Photosensitizer

Verteporfin (trade name Visudyne) belongs to a second generation of porphyrin-based photosensitizer that can be activated by light (wavelength 689nm). It can be used for photodynamic therapy for macular degeneration. Drugs can selectively penetrate into the abnormal blood vessels, generate reactive oxygen species and occlude the abnormal blood vessels with the help of non-thermal laser irradiation, further terminating blood vessel leakage, and saving vision.
Upon being activated by the light, Visudyne forms a cytotoxic product in an aerobic environment. During this process, the porphyrin transfers the absorbed energy to oxygen and forms single-oxygen with a high activity and a short maintenance time. The single-oxygen destroys the biological structure within its range of diffusion. This process leads to localized vascular atresia and cell destruction, further leading to cell death in a particular environment.
In plasma, verteporfin is mainly carried by low density lipoprotein (LDL). The application of Visudyne for photodynamic therapy (PDT) has selectivity. On the one hand, it depends on the choice of light irradiation site. On the other hand, the expression of LDL receptors is enhanced in rapidly proliferating cells, including choroidal neovascular endothelial cells, so that rapid proliferative cells can selectively and rapidly ingest and accumulate verteporfin. Choroidal neovascularization is more rapid and selective than retinal pigment epithelium in absorbing the Visudyne, whereas in other ocular structures, the drug content is small. Therefore, the drug can selectively destroy choroidal neovascularization. It can be used for the treatment of continuous deterioration or loss of vision caused by wet age-related macular degeneration, pathological myopia and ocular histoplasmosis related to the choroidal neovascularization
The above information is edited Andy from ChemicalBook.

Administration and Dosage

Verteporfin is suitable for the treatment of patients of age-related macular degeneration, pathologic myopia or suspected ocular histoplasmosis with a typical predominantly central choroidal neovascularization. There is no sufficient evidence to support its efficacy on the treatment of patients with occult central choroidal neovascularization.
Intravenous administration, the drug treatment process contains two steps: ① intravenous administration: Formulate 2 mg/mL injection with sterile injection of water at a body surface area of 6 mg/m2. Diluted to 30 mL with 5% GS and inject for 10 minutes at the rate of 3mL/min. The diluent should be avoided of light within 4 hours. ② non-thermal diode laser activation: within the 15 minutes after the start of injection, apply a laser of constant energy at wavelength of 689 ± 3nm for irradiation towards patients. During the treatment of choroidal neovascularization, the recommended laser dose at the local focus should be 50 J/ cm2 with laser intensity of 600mW/cm2. The irradiation process should be completed within 83 seconds.

Adverse reactions

Common adverse effects of Visudyne include visual impairment. Local infusion and rash may occur during local injection. It can be occurred of cataract, diplopia, tears, conjunctivitis, dry eyes, eye itching, severe visual loss and conjunctiva, retinal and vitreous hemorrhage, high blood pressure, atrial fibrillation, peripheral vascular disorders, varicose veins, hypoesthesia, sleep disorders, headache, dizziness, weakness, fever, creatinine, cough, pharyngitis, pneumonia, influenza-like syndrome, back pain, abnormal liver function test indicators, prostate disorders, proteinuria, nausea, constipation, gastrointestinal cancer, eczema, anemia, reduction or increases in leukocyte count, hearing impairment and so on.

Precautions

Visudyne should be disabled in patients who are highly allergic to it and its derivatives, and patients who received other photosensitizers within 3 months or with porphyria. Patients of serious or moderately serious liver dysfunction should be cautious upon receiving vitamin treatment. Vitamin and other drugs should not be dissolved in the same solution. Avoid direct exposure to drugs. If a patient has a severe vision loss (vision loss or more than 4 lines) within 1 week after treatment, the patients should discontinue the treatment until the vision returns to the initial state. Care should be taken before weighing the pros and cons of treatment. Patients of liver dysfunction and photodynamic therapy discomfort should take with caution; patients, within 6 days after treatment, should avoid exposure of the skin and eyes to light; avoid excessive and prolonged treatment. Do not use in a brightly lit environment. Avoid the use of visudyne salt solution. If liquid spills, wipe it with a damp cloth. Do not let it touch the eye or skin. Verteporfin leakage may cause severe pain, inflammatory reactions, and discoloration at the injection site. Analgesics can be simultaneously given to relieve pain during the injection. If you find verteporfin leakage, immediately stop the injection, and give cold pressure. The affected area should be carefully protected against direct light exposure until swelling and skin color return to normal. Vitamins should be used with care for patients with general anesthesia.
Patients treated with Visudyne were in a light-sensitive state within 48 hours of injection. Within 48 hours of treatment, the skin and eyes mustn’t be exposed directly to daylight or bright artificial light. If you have to be exposed to the outdoors during the day within 48 hours of treatment, you should wear a suitable jacket and wear sunglasses for protection.

Description

Verteporfin was introduced in Switzerland as a second-generation photosensitizer for photodynamic therapy of wet age-related macular degeneration in patients with subfoveal choroidal neovascularisation. It is constituted of a mixture of two regioisomers resulting from nonselective monohydrolysis of the methyl tetraester. Upon irradiation with a lowenergy nonheat-generating laser light of 689nm wavelength, both regioisomeric benzoporphyrins are responsible for the local generation of singlet oxygen leading to free radical damage of neovascular endothelial cells in subfoveal lesions of patients with agerelated macular degeneration. The lipophilic drug is injected i.v. as a liposomal formulation in order to favor its uptake by plasma lipoproteins and distribution to cells with a high expression of low density lipoprotein receptors such as tumor and neovascular endothelial cells. Verteporfin is also being developed for the treatment of other eye diseases, nonmelanoma skin cancer and psoriasis.

Description

Verteporfin is a photosensitizer used during photodynamic therapy to eliminate abnormal blood vessels in the eye that are associated with conditions such as macular degeneration. It accumulates in these abnormal blood vessels and, when activated by nonthermal red light with a wavelength of 693 nm in the presence of oxygen, produces a highly reactive short-lived singlet oxygen and other reactive oxygen radicals, generating local damage to the endothelium and vessel occlusion. Verteporfin can also inhibit autophagosome formation by directly targeting and modifying p62, a scaffold and adaptor protein that binds both polyubiquitinated proteins destined for degradation and LC3 on autophagosomal membranes.

Originator

QLT Inc. (Canada)

Uses

Treatment of age-related macular degeneration

Uses

Verteporfin is a photosensitizer that is used in photodynamic therapy (PDT). Verteporfin can accumulate in tumor tissues allowing for 30 to 150 minutes optimal PDT after intravenous administration.

brand name

Visudyne (QLT).

Biochem/physiol Actions

Verteporfin is a photosensitizer for photodynamic therapy to eliminate the abnormal blood vessels in the eye associated with conditions such as macular degeneration. Verteporfin accumulates in abnormal blood vessels and, when stimulated by nonthermal red light with a wavelength of 693 nm in the presence of oxygen, produces highly reactive short-lived singlet oxygen and other reactive oxygen radicals, resulting in local damage to the endothelium and blockage of the vessels. Verteporfin localizes predominantly in mitochondria.

storage

Store at -20°C

References

References/Citations: