U.S. patent number RE37,180 [Application Number 09/301,320] was granted by the patent office on 2001-05-15 for photochemotherapeutical obstruction of newly-formed blood vessels.
This patent grant is currently assigned to Meiji Seika Kaisha, Ltd.. Invention is credited to Naoki Hayashi, Keisuke Mori, Shigeru Mori, Masataka Ohta, Masaru Sonoda, Shin Yoneya.
United States Patent |
RE37,180 |
Mori , et al. |
May 15, 2001 |
Photochemotherapeutical obstruction of newly-formed blood
vessels
Abstract
A photosensitive tetrapyrrole derivative having formula (I)
##STR1## where n stands for 1 or 2 or a pharmaceutically acceptable
salt thereof is useful as an effective ingredient in an obstruent
composition for photochemotherapeutically obstructing neovascular
vessels. The photosensitive tetrapyrroles of the formula (I) may be
administered in a photochemotherapeutic method for obstructing
neovascular vessels, particularly choroidal and retinal
neovascularizations.
Inventors: |
Mori; Keisuke (Saitama-ken,
JP), Ohta; Masataka (Saitama-ken, JP),
Mori; Shigeru (Saitama-ken, JP), Yoneya; Shin
(Saitama-ken, JP), Hayashi; Naoki (Saitama-ken,
JP), Sonoda; Masaru (Saitama-ken, JP) |
Assignee: |
Meiji Seika Kaisha, Ltd.
(Tokyo, JP)
|
Family
ID: |
16881405 |
Appl.
No.: |
09/301,320 |
Filed: |
April 29, 1999 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
616177 |
Mar 15, 1996 |
05633275 |
May 27, 1997 |
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Foreign Application Priority Data
|
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Sep 6, 1995 [JP] |
|
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7-228760 |
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Current U.S.
Class: |
514/410 |
Current CPC
Class: |
A61P
27/02 (20180101); A61P 43/00 (20180101); A61P
27/00 (20180101); A61P 27/04 (20180101); A61K
31/409 (20130101); A61K 41/0071 (20130101) |
Current International
Class: |
A61K
41/00 (20060101); A61K 31/409 (20060101); A61K
031/40 () |
Field of
Search: |
;514/410 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
"Role of Neovasculature and Vascular Permeability on the Tumor
Retention of Photodynamic Agents", Roberts et al, Cancer Research,
52, 924-930, Feb. 15, 1992. .
"In Vivo Studies on the Utilization of Mono-L-aspartyl Chlorin
(Npe6) for Photodynamic Therapy", Nelson et al, Cancer Research,
47, 4681-4685, Sep. 1, 1987. .
"Photodynamic Therapy of Subretinal Neovascularization in the
Monkey Eye", Miller et al, Arch. Ophthalmol, vol. 111, Jun.
1993..
|
Primary Examiner: Henley, III; Raymond
Attorney, Agent or Firm: Larson & Taylor PLC
Claims
We claim:
1. A method for photochemotherapeutically obstructing neovascular
vessels as .[.foraged.]. .Iadd.formed .Iaddend.in a patient having
the neovascular vessels, which comprises administering orally or
parenterally to the patient an amount of a compound having the
formula (I): ##STR5##
where n stands for an integer of 1 or 2, or a pharmaceutically
acceptable salt thereof, allowing said compound administered to
accumulate in the neovascular vessels to be obstructed after the
administration of said compound to the patient, irradiating a part
or all or some parts of the neovascular vessels to be obstructed,
with a laser beam until the compound accumulated in the neovascular
vessels has been elicited photochemically, terminating the
irradiation of the laser beam, and then allowing the laser
beam-irradiated part or parts of the neovascular vessels to be
obstructed.
2. A method according to claim 1, which is applied to the
photochemotherapeutical obstruction of the choroidal or retinal
neovascularization..Iadd.
3. A method according to claim 1, in which mono-L-aspartyl chlorin
e6 or its tetra-sodium salt is administered..Iaddend.
Description
FIELD OF THE INVENTION
The present invention relates to an obstruent composition for use
in photochemotherapeutical obstruction or occlusion of newly-formed
or neovascular blood vessels as formed in a patient. The present
invention also relates to a method for photochemotherapeutically
obstructing neovascular vessels as formed in a patient having the
neovascular vessels in eyes, cutaneous tissue or visceral
tissue.
BACKGROUND OF THE INVENTION
The photochemotherapeutical method means such a chemotherapeutical
method which makes use of a photosensitive substance capable of
displaying a therapeutic action or medical action for the first
time only when said substance is elicited photochemically by being
irradiated with light, for example, ultraviolet rays or a beam of
laser light, and in which, after the administration of said
photosensitive substance, either such part or parts of the tissues
of a living body of the patient where the photosensitive substance
as administered has been presented and accumulated, or a flow of
blood as formed by extracorporeal circulation of the blood
containing said photosensitive substance is exposed to irradiation
with light or is subjected to any other measure so that the
photosensitive substance is elicited photochemically to display its
therapeutic or medical action.
Upon the beginning of the development of the photochemotherapy, the
photosensitive substances of a first generation, of which a
representative is photofrin, were used in the therapeutic treatment
of tumors or cancerous tissues. From the viewpoint of clinical
application, however, the .[.photosensitvive.].
.Iadd.photosensitive .Iaddend.substance of the first generation are
accompanied by their drawback that they are very much slowly
metabolized in vivo.
Known photochemotherapeutic methods for treatment of tumor or
cancer include such a method wherein such a photosensitiser having
no anti-neoplastic activity by itself but having an affinity for
tumor or cancer is administered to a patient and the
photosensitiser is allowed to concentrate in the tissue of tumor or
cancer, followed by irradiating the tumor or cancerous tissue with
a laser light so that the tumor or cancerous tissue is treated
therapeutically. The photosensitiser used in the above-mentioned
method can exert such a mechanism that the photosensitiser, when
exposed to the laser light, absorbs the photo-energy of the laser
and becomes elicited photochemically and the energy of the elicited
photosensitiser can then .[.elicits.]. .Iadd.elicit .Iaddend.the
oxygen components present in the tumor or cancer cells to produce
activated oxygen, and that the activated oxygen so produced can
give damages to the tumor or cancer cells so as to cause necrosis
of the tumor or cancer tissue.
For instance, in Japanese patent publication No. 88902/94 and No.
89000/94 as well as European patent publication No. 168832-B1 and
U.S. Pat. No. 4,675,338, there is disclosed that diagnosis and
therapeutic treatment of tumor or cancereous tissues is conducted
with using as a photochemotherapeutic agent such fluorescent
tetrapyrrole derivatives or salts thereof which are prepared by
condensing an amino-dicarboxylic acid of 4 to 10 carbon atoms, for
example, aspartic acid or glutamic acid, via one or more amido
linkages with at least one carboxyl group of certain tetrapyrrole
compounds bearing a plurality of carboxyl group(s) and side
chain(s) of carboxylic acids. There is also disclosed that the
aforesaid fluorescent tetrapyrrole derivative, which has
concentrated and been accumulated in the tissue of tumor or cancer,
can be elicited photochemically by being irradiated with intense
light, for example, a laser beam and thereby becomes able to exert
its effects of killing the tumor or cancer cells.
Further, it is known that the formation of neovascular blood
vessels, namely neovascularization occurs in various ocular tissues
in the eyes due to certain pathogenic causes.
Neovascularization of any ocular tissue causes serious visual
disturbance. Particularly, choroidal neovascularization which takes
place accompanying with age-related macular degeneration is now
becoming a primary cause for acquired blindness. In age-related
macular degeneration, choroidal neovascularization causes
subretinal hemorrhage, exudates and fibrosis, leading to severe
visual loss.
Laser photocoagulation has heretofore been used for the therapeutic
treatment of choroidal (ocular) neovascularization but is not a
perfect method, because it damages overlying sensory retina by
propagating heat. Compared with the above method, photochemotherapy
using a laser beam is expected to provide a satisfactory
therapeutic method for neovascularization, if the neovascular,
ocular blood vessels can be selectively targeted by the
photochemotherapy with the laser beam.
Sometimes, it is also desired to selectively obstruct or occlude
newly-formed vessels other than the above-described ocular
.[.Ones.]. .Iadd.ones.Iaddend., for example, those formed in skin
tissue or visceral tissue due to a certain pathogenic cause.
An object of the present invention is to provide a new obstruent
composition for use in obstructing or occluding
photochemotherapeutically and selectively a part or all or some
parts of newly-formed vessels formed in the various ocular tissues,
as well as newly-formed vessels formed in other tissues in vivo.
The other object of the present invention is provide a therapeutic
method for photochemotherapeutically obstructing neovascular blood
vessels as formed in a patient having the neovascular blood
vessels. Another objects of the present invention will be clear
from the following descriptions.
DETAILED DESCRIPTION OF THE INVENTION
In order to achieve the above-mentioned objects of the present
invention, the present inventors have made investigations for
seeking a photochemotherapeutic agent which is useful and suitable
to obstruct or occlude various kinds of neovascular vessels,
especially choroidal or retinal neovascularization. As a result of
the investigations, the present inventors have now found that when
patients having the neovascular vessels are administered with a
photosensitive substance, .[.mono-L-aspartly-chlorin e6.].
.Iadd.mono-L-aspartyl chlorin e6 .Iaddend.tetra-sodium salt
.[.(hereinafter abbreviated as "NPe6").]. which is now employed and
tested in a clinical application of a photochemotherapeutic
treatment of malignant tumors and is known to be quickly uptaken
into and excreted from the human and animal body, .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt .Iaddend.can
concentrate into and be accumulated well in the active lesions of
the neovascular tissues, and that .[.NPe6.]. .Iadd.mono-L-aspartyl
chlorin e6 tetra-sodium salt .Iaddend.present in the neovascular
vessels can be elicited by irradiation with a laser beam at a
wavelength of 664 nm and the elicited .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt .Iaddend.is able
to generate the activated oxygen and thereby to cause necrosis of
the vascular endothelial cells and occlusion of choroidal
neovascularization.
Further, the present inventors have found that not only the
above-mentioned .[.NPe6 substance.]. .Iadd.mono-L-aspartyl chlorin
e6 tetra-sodium salt .Iaddend.but also a tetrapyrrole derivative
represented collectively by a general formula (I) given below,
including the .[.NPe6 substance.]. .Iadd.mono-L-aspartyl chlorin e6
tetra-sodium salt.Iaddend., are utilizable effectively and highly
safely as such an obstruent for obstructing or clogging the
newly-formed vessels, which can be activated by irradiation with a
light when it is used in a photochemotherapy. It has also been
found that the tetrapyrrole derivative having the general formula
(I) given below are especially useful and effective with a high
safety to obstruct the choroidal neovascularization as well as the
retinal neovascularization. On the basis of these findings, the
present inventors have completed the present invention.
In a first aspect of the present invention, therefore, there is
provided an obstruent composition for photochemotherapeutically
obstructing the neovascularization, which comprises as the
effective ingredient a compound represented by the formula (I):
##STR2##
where n stands for an integer of 1 or 2, or a pharmaceutically
acceptable salt thereof; and a pharmaceutically acceptable carrier
for the effective ingredient.
The tetrapyrrole derivative of the general formula (I), which is
used as the effective ingredient in the obstruent composition
according to the first aspect of the present invention, may
preferably be its stereoisomer having a steric configuration shown
below and represented by the following general formula (I'):
##STR3##
where n stands for an integer of 1 or 2.
Among the compounds of the general formula (I') shown above, the
compound of the formula (I') where n is 1 is such compound wherein
L-aspartic acid is combined via an amido linkage with the side
chain group .[.--CH.sub.2 CH.sub.2 COOH.]. .Iadd.--CH.sub.2 COOH at
the 20-position .Iaddend.of the tetrapyrrole ring shown in the
above formula (I'). This particular compound is
mono-L-aspartyl-chlorin e6. This mono-L-aspartyl-chlorin e6 may
preferably be in the form of its tetra-sodium salt .[.(abbreviated
as "NPe6").]. at the four carboxyl groups of the compound.
Among the compounds of the general formula (I') shown above, the
compound of the formula (I') where n is 2 is such compound wherein
L-glutamic acid, in stead of said L-aspartic acid, is combined via
the amido linkage of the side chain group .[.--CH.sub.2 CH.sub.2
COOH.]. .Iadd.--CH.sub.2 COOH at the 20-position .Iaddend.of the
tetrapyrrole ring shown in the formula (I'). This compound is
mono-L-glutamyl-chlorin e6.
While, the compound of the general formula (I) or formula (I')
generally may form a salt thereof by reaction with a base. Examples
of such salt with the base may include the sodium, potassium,
calcium, magnesium, ammonium, triethylammonium, trimethylammonium,
morpholine and piperidine salts.
The compound of the above formula (I), particularly the compound of
the above formula (I') is able to concentrate into and be
accumulated well in the blood vessels in the eyes after the
administration of said compound. And, the compound accumulated in
the ocular blood vessels is able to obstruct the choroidal or
retinal neovascularization when the compound is activated by the
action of a laser beam irradiating a limited region of the
neovascular tissues. In particular, .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt .Iaddend.is a
photosensitivity-improver consisting essentially of a single
compound wherein one molecule of L-aspartic acid is combined via
the amido linkage with the side chain group .[.--CH.sub.2 CH.sub.2
COOH.]. .Iadd.--CH.sub.2 COOH at the 20-position .Iaddend.attached
to the chlorin ring which is formed by the reduction of a single
one double-bond of the D ring of the tetrapyrrole nucleus.
.[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt
.Iaddend.is characterized by that this specific compound can absorb
well a light having a wavelength of 664 nm. Besides, .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt .Iaddend.has a
high metabolic speed which is at least 10 times faster than that of
the aforesaid "photofrin", and at the end of 10 hours from the
administration of .[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6
tetra-sodium salt.Iaddend., the level of .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt .Iaddend.in the
blood plasma can reach a level as high as 1/500 of the dosage of
administration of .[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6
tetra-sodium salt.Iaddend..
It has .[.als0.]. .Iadd.also .Iaddend.been found that .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt .Iaddend.is
further characterised by that .[.NPe6.]. .Iadd.mono-L-aspartyl
chlorin e6 tetra-sodium salt .Iaddend.has a nature of exhibiting
affinity to the serum albumin, that .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt .Iaddend.is of a
low liposolubility and thus is hard to penetrate and diffuse into
the healthy normal tissues having the barrier in vivo, and that
.[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt
.Iaddend.is able to transfer into the in vivo cells not by the
diffusion of the .[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6
tetra-sodium salt .Iaddend.molecules but by the phagocytosis and/or
pinocytosis of the .[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6
tetra-sodium salt .Iaddend.molecules. The above-mentioned
characteristic properties of .[.NPe6.]. .Iadd.mono-L-aspartyl
chlorin e6 tetra-sodium salt .Iaddend.reveal that .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt .Iaddend.is a
photosensitive agent which can advantageously be utilized to
photochemotherapeutically obstruct various ocular
neovascularizations.
Incidentally, the tetrapyrrole derivative of the general formula
(I) shown above and the processes of producing it are disclosed in
the aforesaid Japanese patent publication No. 88902/94 and No.
89000/94 as well as in the European patent application publication
No. 168832-B1 specification and U.S. Pat. No. 4,675,338.
The obstruent composition for obstructing the newly-formed vessels
according to the first aspect of the present invention is useful to
be used in a photochemotherapeutic treatment of a variety of ocular
diseases. The composition of the present invention is particularly
effective to therapeutically treat various diseases caused by the
neovascularization occurring in the choroid, for example,
age-related macular degeneration, and the neovascularization
occurring in the retina, for example, proliferative diabetic
retinopathy, and so on.
The obstruent composition according to the first aspect of the
present invention, or the compound of the formular (I) or the
formula (I') itself which is incorporated as the effective
ingredient in said obstruent composition, may be administered to a
patient either orally or parenterally by intravenous or
intramuscular injection, or percutaneously. For instance, the
obstruent composition of the present invention may be formulated
into such a preparation which contains the compound of the formula
(I) or (I') in the form of its sodium salt and has been lyophilized
in the form of a sterile powder containing no pyrogen. A preferred
preparation of the composition is an injectable and isotonic
aqueous solution containing the compound of the formula (I) or
(I'). When the compound of the formula (I) or (I') has been
administered to a patient, it is possible that a laser light is
irradiated to the neovascular vessels formed in the affected part
or parts of the patient at an appropriate time between the time
immediately after the administration and the time of up to 6 hours
from the administration of said compound.
In the composition for oral administration, the compound of the
formula (I) as the effective ingredient may be admixed with a
pharmaceutically acceptable solid or liquid carrier or vehicle. The
orally admintstrable composition may be formulated into
intestinally absorbable forms, such as tablets, buccal
preparations, troches, capsules, sweetened tinctures, suspensions,
syrups, wafers, or the like.
It is preferable that the composition so prepared contains the
compound of the formula (I) or (I') as the effective ingredient in
an amount of at least 0.1% by weight on the weight basis of the
composition. The proportion of the compound of the formula (I) or
(I') in the composition naturally varies depending on the form of
the preparation as formulated of the composition. A preferred
proportion of the effective compound of the formula (I) or (I')
maybe in a range of from about 2% to 60% by weight of each dosage
unit of the composition. It is desirable that each dosage unit of
the orally administrable composition as formulated contains about
50 to 300 mg of the compound of the formula (I) or (I') as the
effective ingredient.
Preferred examples of the preparation form for injection include an
aqueous sterile solution or dispersion and a sterile injectable
lyophilized preparations. Illustrative carriers useful therefor
include water, ethanol, and polyols such as glycerol, propylene
glycol and liquid polyethylene glycol, as well as desired mixed
solvents thereof. In addition, a solvent or dispersing medium
containing a vegetable oil can also be used. The liquid-form
preparations can be maintained appropriately flowable by adding a
viscosity modifier such as lecithin. In the case of a
dispersion-type preparation, its appropriate flowability can be
maintained by controlling the effective ingredient compound to a
desired particle size or by adding a surfactant. In many cases, it
is preferred to add an isotonic agent such as sugar or sodium
chloride. The injectable composition can contain an added agent
capable of sustaining the absorption of the effective ingredient
compound, such as aluminum monostearate or gelatin.
The dosage of the compound of the formula (I) contained in the
obstruent composition according to the present invention may vary
depending on the purpose of the treatment, the severity of the
symptoms and the like. In general, a dose of 0.2 to 10 .[.mg.].
.Iadd.mg/kg .Iaddend.of the effective compound may be administered
once a day to an adult.
Examples of the irradiation source for a laser beam, which is for
use in the therapeutic treatment after the administration of the
obstruent composition, include a powerful continuous laser beam
sources equipped with optical filters, excited pigments and other
laser-beam feeding systems. Among them, desired is an irradiation
source which can generate a laser beam at a full output power of at
least 500 mW to give a radiation intensity of 10 to 100
mW/cm.sup.2. Some of commercially-available laser generators can
satisfy the above-mentioned standards for the laser generation.
When the acute toxicity of .[.NPe6.]. .Iadd.mono-L-aspartyl chlorin
e6 tetra-sodium salt .Iaddend.was tested by intravenous injection
to CD-1 mice (male), it has been found that .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt
.Iaddend.exhibits an LD.sub.50 value of 164 mg/kg. From further
photo-toxicity tests with .[.NPe6.]. .Iadd.mono-L-aspartyl chlorin
e6 tetra-sodium salt.Iaddend., it has been found that .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt .Iaddend.is a
highly safe compound which does not involve adverse side reactions
such as erythema and edema.
As described in the above, the tetrapyrrole.[...]. derivative of
the formula (I) or (I') shown hereinbefore is evidently useful in
the photochemotherapy to .[.abstruct.]. .Iadd.obstruct .Iaddend.or
clog the neovascular vessels as formed in a patient having the
neovascular vessels produced due to certain pathogenic causes.
In a second aspect of the present invention therefore, there is
provided a method for photochemotherapeutically obstructing
neovascularization or neovascular blood vessels as formed in a
patient having the neovascular blood vessels, which comprises
administering orally or parenterally to the patient an amount of
.Iadd.a .Iaddend.compound of the formula (I): ##STR4##
where n stands for an integer of 1 or 2, or a pharmaceutically
acceptable salt thereof, allowing said compound administered to
accumulate in the neovascular vessels to be obstructed after the
administration of said compound to the patient, irradiating a part
or all or some parts of the neovascular vessels to be obstructed,
with a laser beam until the compound accumulated in the neovascular
vessels has been elicited photochemically, terminating the
irradiation of the laser beam, and then allowing the laser
beam-irradiated part or parts of the neovascular vessels to be
obstructed.
The therapeutic method according to the second aspect of the
present invention is especially useful to be applied to
photochemotherapeutic obstruction of the choroidal or .[.rotanal.].
.Iadd.retinal .Iaddend.neovascularization formed in the patient.
The compound of the formula (I) used in the method of the second
aspect of the present invention may preferably be a compound of the
formula (I') shown hereinbefore and may be administered in a dosage
as explained for the obstruent composition according to the first
aspect of the present invention hereinbefore.
The present invention is now illustrated with reference to the
following Examples, to which the present invention is limited in no
way.
TEST EXAMPLE 1
Injectable aqueous solutions containing .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt
.Iaddend.dissolved in a physiological saline were intravenously
injected into seven eyes of four, normal pigmented rabbits,
respectively at doses of .[.NPe6.]. .Iadd.mono-L-aspartyl chlorin
e6 tetra-sodium salt .Iaddend.of 25 mg/kg, 50 mg/kg and 100 mg/kg.
Immediately after the intravenous injection or one hour after the
intravenous injection of the .[.NPe6.]. .Iadd.mono-L-aspartyl
chlorin e6 tetra-sodium salt .Iaddend.solution, predetermined
regions of the blood vessels in the seven eyes under test were
irradiated with a beam of laser light having a wavelength of 664 nm
(as emitted from a semiconductor generator for laser, manufactured
by Matsushita Electric .[.works.]. .Iadd.Works .Iaddend.Ltd.,
Japan) for 9 seconds or 90 seconds, while the laser beam having a
power of 10 mW was injected to irradiate several spots each of 500
.[..mu.n.]. .Iadd..mu.m .Iaddend.in its diameter within the blood
vessels to be irradiated. The predetermined regions (that is, said
spots) of the blood vessels to be irradiated with the laser beam
had been marked preliminarily by photo-coagulation by means of an
argon laser beam. Immediately after the irradiation with the laser
at 664 nm, as well as one week after the irradiation and one month
after the irradiation with the laser at 664 nm, the fundus of the
eyes under test was examined by fluorescein angiography. In
selected cases, fundus treated with .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt .Iaddend.were
further examined histologically.
(1) With the treated eyes which had been subjected to the
irradiation with the laser at 664 nm immediately after the
intravenous injection of the .[.NPe6.]. .Iadd.mono-L-aspartyl
chlorin e6 tetra-sodium salt .Iaddend.solution and were observed
and examined by the fluoresein angiography made one week after the
laser irradiation, it was found that the obstruction took place in
the choroidal vessels at all the doses of .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt .Iaddend.of 25,
50 and 100 mg/kg, and that the degree of the obstruction in the
choroidal vessels increased with an increased doses of .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt.Iaddend..
(2) Comparisons were made between the test results obtained when
the intravenous injection of a dose of 25 mg/kg of .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt .Iaddend.was
followed immediately by the irradiation with the laser at 664 nm,
and the test results obtained when the intravenous injection of a
dose of 25 mg/kg of .[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6
tetra-sodium salt .Iaddend.was followed by the laser irradiation
one hour after the intravenous injection of .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt.Iaddend.. It was
then found that the extent of damages incurred in the choroidal
vessels is reduced at the laser irradiation as made one hour after
the intravenous injection of the .[.NPe6.]. .Iadd.mono-L-aspartyl
chlorin e6 tetra-sodium salt .Iaddend.solution, than that incurred
at the laser irradiation made immediately after the intravenous
injection of .[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6
tetra-sodium salt.Iaddend.. This likelihood could be observed
commonly for all the doses of .[.NPe6.]. .Iadd.mono-L-aspartyl
chlorin e6 tetra-sodium salt.Iaddend.. This reveals that the level
of .[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt
.Iaddend.in the blood after the administration of .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt .Iaddend.can
decrease quickly during an earlier period after the administration
of .[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6 tetra-sodium
salt.Iaddend., and that .[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6
tetra-sodium salt .Iaddend.can be metabolized well after its
administration into a human or animal body.
(3) The eye having received the intravenous injection of a dose of
25 mg/kg of .[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6
tetra-sodium salt .Iaddend.was subjected to the irradiation with
the laser at 664 nm immediately after the intravenous injection of
.[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6 tetra-sodium
salt.Iaddend.. The eye so treated was subsequently observed under
light microscope at the end of 2 hours after the laser irradiation.
By this observation, it was found that endothelial cells of the
chorio-capillaris had been swollen and necrotized and the
choriocapillaris were obstructed. In the sensory retina of the eye
so treated, it was observed that there took place such partial
movements of the inner and outer segments of photoreceptor cells
into the subretinal space, which might be considered to be a slough
of the visual cells. However, it was found that the whole structure
of the sensory retina could be retained intact as a whole. From
these findings, it is presumed that the associated actions of
.[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt
.Iaddend.and the irradiation with laser can be focused on
choriocapillaris itself only but do not directly affect the sensory
retina to a substantial extent.
(4) The eye having received the intravenous injection of a dose of
25 mg/kg of .[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6
tetra-sodium salt .Iaddend.was subjected to the irradiation with
the laser at 664 nm immediately after the intravenous injection of
.[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6 tetra-sodium
salt.Iaddend.. The laser-irradiated parts of the eye so treated
were subsequently observed under light microscope at the end of 1
hour after the laser irradiation. By this observation, .[.At.].
.Iadd.it .Iaddend.was found that the choroidal blood vessels, more
particularly the choriocapillaris continued to have been
obstructed. From these findings, it is considered that the
obstruction of the blood vessels as achieved by the associated
actions of the administration of .[.NPe6.]. .Iadd.mono-L-aspartyl
chlorin e6 tetra-sodium salt .Iaddend.and the irradiation with
laser can be maintained for a prolonged period directly after the
laser irradiation.
(5) Comparisons under light microscope were made between the
coagulated lesions of the choroidal blood vessels, which had been
formed by the thermal actions of a conventional irradiation with an
argon laser ray, and the coagulated lesions of the choroidal
vessels, which had been formed by the administration of .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt .Iaddend.and the
subsequent irradiation with .[.Laser.]. .Iadd.laser .Iaddend.ray
according to the present invention, wherein the laser irradiation
was made immediately after the administration of a dose of
.[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt
.Iaddend.of 25 mg/kg and the microscopic observations were done at
the end of one week after the laser irradiation.
By these observations, it was found that the choroidal vessels were
obstructed to a substantially same degree in the former case and
the latter case, and that the damages incurred in the sensory
retina were lighter in the latter case, that is, upon the
administration of .[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6
tetra-sodium salt .Iaddend.associated with the subsequent
irradiation with laser ray, than those in the former case, that is,
upon the conventional photo-coagulation with the argon laser ray.
This finding clearly shows that the action of the argon laser ray
used in the conventional photo-coagulation is different from the
action of the laser irradiation as associated with the
administration of the photochemotherapeutic obstruent, .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt
.Iaddend.according to the present invention, and also suggests that
the present invention makes it feasible to achieve a selective
obstruction in such predetermined regions of the blood vessels,
where an effective amount of .[.NPe6.]. .Iadd.mono-L-aspartyl
chlorin e6 tetra-sodium salt .Iaddend.is presented there.
TEST EXAMPLE 2
Normal pigmented rabbits of a sort same as that employed in the
above Test Example 1 were intravenously administered with a dose of
.[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt
.Iaddend.of 100 mg/kg at their eyes in the same manner as in Test
Example 1 and were subsequently housed for one week under ordinary
fluorescent tubes of the usual living environments without
receiving any irradiation with the laser ray. The eyes of the
rabbits so housed were then examined by observing the fluorescein
angiography and the light microscopic views of the fundus of the
eyes. It was then found that the so housed rabbits were able to
retain the normal structures in the retina and choroid of their
eyes, despite that they had received the administration of a
maximum dosage of .[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6
tetra-sodium salt.Iaddend.. This finding reveals that .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt .Iaddend.is a
photosensitive substance with a high safety, which does not
adversely affect mammals when the mammals are kept under ordinary
fluorescent lights of the usual living environments.
Next, some illustrative formulations of the obstruent composition
according to this invention are given below.
EXAMPLE 1 OF FORMULATION
The following ingredients were mixed together in the proportions by
weight as indicated below, to prepare a basal powder:
Sucrose 80.3 grams Tapioca starch 13.2 grams Magnesium stearate 4.4
grams
The basal powder so obtained was mixed well with an appropriate
amount of .[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6 tetra-sodium
salt .Iaddend.and the resulting mixture was shaped into tablets by
a conventional tableting method, so that there were produced
tablets each containing 100 mg of .[.NPe6.]. .Iadd.mono-L-aspartyl
chlorin e6 tetra-sodium salt .Iaddend.as the active ingredient.
EXAMPLE 2 OF FORMULATION
In a volume of physiological saline were dissolved 200 mg of
.[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt
.Iaddend.to give an aqueous solution which contained .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt
.Iaddend.dissolved in the saline at a final .[.NPe6.].
.Iadd.mono-L-aspartyl chlorin e6 tetra-sodium salt
.Iaddend.concentration of 20 mg per ml. The resulting solution was
sterilized in a conventional manner to afford an injectable
solution of .[.NPe6.]. .Iadd.mono-L-aspartyl chlorin e6
tetra-sodium salt.Iaddend., which is suitable for intravenous
administration and also for intramuscular administration for the
photochemotherapeutic purposes.
* * * * *