# US 5,705,518 A · Method of activating photosensitive agents

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- Number: US 5,705,518 A
- Document ID: US5705518A
- Status: Granted
- Kind: A
- Application number: 08/391,414
- Filed: 1995-02-16
- Granted: 1998-01-06
- Earliest claimed: 1992-11-20
- Assignees: The University of British Columbia
- Inventors: Anna M. Richter; Elizabeth Waterfield; Julia G. Levy
- Web page: https://patentgrep.com/patent/US5705518A

## CPC

- A61N 5/062: {Photodynamic therapy, i.e. excitation of an agent}
- A61K 41/0071: {PDT with porphyrins having exactly 20 ring atoms, i.e. based on the non-expanded tetrapyrrolic ring system, e.g. bacteriochlorin, chlorin-e6, or phthalocyanines}
- A61P 35/00: Antineoplastic agents
- A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B)
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)
- A61P: SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS

## Abstract

A method of administering photodynamic therapy begins with administering to an animal an effective amount of a photosensitizing agent which is less than about one half of the usual clinical dose for the photosensitizing agent. Then, following a post injection interval which is less about one quarter of the usual post injection interval, an effective dose of light which is less than about one half of the usual clinical dose of light used in conjunction with the photosensitizing agent is administered to the animal.

## Claims

### Claim 1

A method to destroy or impair an area of neovascularization in an animal, which animal comprises both an area of neovascularization and normal tissue, which method comprises:
(a) administering to said animal an effective amount of a photosensitizing agent;
(b) transcutaneously administering to said area of neovascularization an effective amount of light of a wavelength that matches an excitation wavelength of said photosensitizing agent,
wherein said light is administered to said area of neovascularization before said photosensitizer has permeated said normal tissue, thus substantially avoiding skin photosensitivity;
and wherein the post-injection time between step (a) and step (b) varies between about one minute and three hours.

### Claim 2 (depends on 1)

The method of claim 1 wherein the effective amount of the photosensitizing agent is approximately less than one half of the clinical dose of said photosensitizing agent.

### Claim 3 (depends on 1)

The method of claim 1 wherein the effective amount of light is less than about half of the clinical dose of light for activation of the photosensitizing agent in photodynamic therapy.

### Claim 4 (depends on 1)

The method of claim 1 wherein the photosensitizer is selected from the group consisting of a chlorin, a bacteriochlorin, a phthalocyanine, a porphyrin, a purpurin, a merocyanine, a pheophorbide and a psoralen.

### Claim 5 (depends on 1)

The method of claim 1 wherein the area of neovascularization is selected from the group consisting of a tumor, an atherosclerotic deposit, a wart, and a psoriatic lesion.

### Claim 6 (depends on 4)

The method of claim 4 wherein said photosensitizer is a porphyrin.

### Claim 7 (depends on 6)

The method of claim 6 wherein the porphyrin is BPD or porfimer sodium.

### Claim 8 (depends on 1)

The method of claim 1 wherein the animal is mammal.

### Claim 9 (depends on 8)

The method of claim 8 wherein the mammal is a human.

### Claim 10 (depends on 1)

The method of claim 1 wherein the post-injection time varies between about one minute and 45 minutes.

### Claim 11

A method to destroy or impair a solid tumor in an animal, which animal comprises both solid tumor and normal tissue, which method comprises:
(a) administering to said animal an effective amount of benzoporphyrin derivative-monoacid (BPD-MA); and
(b) transcutaneously administering to said tumor an effective amount of light of a wavelength that matches an excitation wavelength of said BPD-MA, wherein said light is administered to said tumor before said BPD-MA has permeated said normal tissue, thus substantially avoiding skin photosensitivity;
and wherein the post-injection time between step (a) and step (b) varies between about one minute and 45 minutes.