Note: Descriptions are shown in the official language in which they were submitted.
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DESCRIPTION
NOVEL DRUG FOR RELIEVING PAIN AND PROMOTING THE REMOVAL OF
CALCULI IN UROLITHIASIS
Technical Field
The present invention relates to a drug for relieving pain and promoting the
removal of calculi in urolithiasis which contains as the active ingredient a
drug
having the stimulating effects on both ~2- and (3s-adrenoceptors.
Background Art
It is known that three subtypes of ~-adrenoceptor, which have been
classified as j31, ~z and 03 are present. Each receptor subtype is distributed
in
specified organs. Pi Adrenoceptor is mainly present in heart and its
stimulation
enhances the function of the heart. f3a-Adrenoceptor is mainly present in
trachea,
peripheral blood vessel and uterus, and smooth muscle of the organs is relaxed
by
the stimulation of this receptor. In addition, it is recently reported that ~s-
adrenoceptor is present in digestive tract and adipocytes. The stimulation of
~9-
adrenoceptor leads to the relaxation of gastrointestinal smooth Tnuscle,
lipolysis
and energy expenditure in adypose tissues and so on.
Thus, the distribution of 0-adrenoceptor subtypes is specified by organs and
tissues. Various :receptor subtypes including (3-adrenoceptor hav* been
actively
studied for developing more effective medicinal treatment of some diseases.
Consequently, efforts have been paid extensively to develop more effective and
highly selective drugs that act on a specified organ. However, P-adrenoceptor
subtypes distributed in human ureter have not been elucidated at all, and the
progress of studies to develop drugs that act more effectively on hurnan
ureter has
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been desired.
Urolithiasis is a disease generating calculi in the lumen of the entire
urinary tract from kidney to urethra. The calculi is thought to be formed in a
series of events such as nucleation of urinary component, crystallization,
aggregation, concretion and enlargement. Urinary flow is often obstructed by
calculi, which results in the rise of intra-ureteral pressure leading to pain.
An
analgesic and an antispastic are prescribed for the pain. However, the use of
the
analgesic is only temporary symptomatic therapy for the pain, and is not
expected
to treat urolithiasis fundamentally at all. The effectiveness of an anti-
cholinergic,
one of the antispastic, is not also satisfactory. Therefore, the drugs which
relieve pain and promote the removal of calculi by widening the ureter with
their
strong relaxing effects are desired (The Journal of Urology, Vol.152, pp.1095-
1098
(1994)).
Disclosure of Invention
We, the present inventors, have studied extensively about drug effects on
human ureter to elucidate 0-adrenoceptor subtypes distributed in human ureter.
As a result, we found surprisingly that (33-adrenoceptor in addition to 02-
adrenoceptor is present in human ureter, thereby accomplishing the present
invention.
The present invention is to provide a novel drug for relieving pain and
promoting the removal of calculi in urolithiasis which contains as the active
ingredient a drug exerting a strong relaxing effect on human ureteral smooth
muscle by stimulating both (3Z- and Ps-adrenoceptors.
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2a
In one particular embodiment there is provided a pharmaceutical
composition for relieving pain related to urolithiasis or promoting the
removal of
calculi in urolithiasis, comprising as an active ingredient a pharmaceutical
having
stimulating effects on both (32- and 03-adrenoceptors in admixture with a
pharmaceutically acceptable carrier.
In accordance with one aspect of the present invention there is provided a
pharmaceutical composition for relieving pain and promoting the removal of
calculi in urolithiasis, containing the active ingredients in the form of a
mixture of
different compounds, each of which compounds has selective stimulating effects
on one or both 02- and 03-adrenoceptors, and which mixture collectively has
selective stimulating effects on both 02- and 03-adrenoceptors.
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= 3
Brief Description of Drawings
Figure 1 illustrates the effect of each drug on contraction of isolated human
ureteral smooth muscle induced by 40 mM of potassium chloride. The axis of
ordinates shows change of ureteral tension after treatment of each drug. The
ureteral tension before the treatment is indicated as 100 %, and the tension
after
the treatment of 10-5 M of isoproterenol which produces maximal relaxation of
ureter is indicated as 0 %. The axis of abscissas shows drug concentrations
(M).
The marks -0-, -*- and -0- show isoproterenol, procaterol and CGP-12,177A,
respectively.
Figure 2 illustrates the effect of each drug on contraction of isolated human
ureteral smooth muscle induced by 40 mM of potassium chloride. The axis of
ordinates shows change of ureteral tension after treatment of each drug. The
ureteral tension before the treatment is indicated as 100 %, and the tension
after
the treatment of 10'6 M of isoproterenol alone which produces maximal
relaxation
of ureter is indicated as 0 %. The axis of abscissas shows concentrations (M)
of
isoproterenol. The marks - O- and - L - show isoproterenol alone and
isoproterenol in the presence of 100 nM of ICI-118,551, respectively.
Best Mode for Carrying Out the Invention
We, the present inventors, made the following experiments using
isoproterenol as a nonselective 0-adrenoceptor stimulant, procaterol as a
selective
P2-adrenoceptor stimulant, CGP-12,177A hydrochloride [chemical name: ( )-4-[3-
[(1,1-dimethylethyl)amino]-2-hydroxypropoxy]-1, 3-dihydro-2H-benzimidazol-2-
one hydrochloride] as a selective (39-adrenoceptor stimulant with (31- and P2
adrenoceptors blocking activities (Molecular Pharmacology, Vol.44, pp.1094-
1104
(1993)), and ICI-118,551 hydrochloride [chemical name: ( )-1-[(2,3-dihydro-7-
methyl-1H-inden-4-yl)oxy]-3-[(1-methylethyl)amino]-2-butanol hydrochloride] as
a
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selective R2-adrenoceptor blocker.
We investigated the effects of the drugs on contraction of human ureteral
smooth muscle induced by potassium chloride. We found that both procaterol, a
selective (32-adrenoceptor stimulant, and CGP-12,177A, a selective P3-
adrenoceptor
stimulant, produced apparent relaxation of the smooth muscle. This result
supports that 53-adrenoceptor is present in human ureter in addition to ~3a
adrenoceptor.
Furthermore, the effects of isoproterenol alone and isoproterenol combined
with 1CI-118,551 were compared in the similar experiment using human ureteral
smooth muscle. We found that the relaxing effect of isoprotcrenol on ureteral
smooth muscle is not blocked completely by ICI-118,551, a selective (3a-
adrenoceptor blocker. Therefore, it was confirmed pharmacologically that R$-
adrenoceptor in addition to A2-adrenoceptor is present in human ureter.
Thus, it becomes clear that both jia- and j3g-adrenoceptors are present in
human ureter. Namely, the drugs having the stimulating effects on both Pa- and
N-adrenoceptors can provide clinically satisfactory relaxation of human
ureter,
which can not be attained by using the existing drugs. The drugs having the
stimulating effects on both 02- and P9-adrenoceptors are very useful for
relieving
pain and promoting the removal of calculi in urolithiasis.
The drugs having the stimulating effects on both Ra- and P3-adrenoceptors of
the present invention have excellent relaxing effects on human ureteral smooth
muscle, and are useful for relieving pain, promoting spontaneous passage of
calculi and the removal of calculi after extracorporeal shock wave lithotripsy
and
so on.
As the drugs having the stimulating effects on both P2- and Ps-adrenoceptors,
the drugs exhibiting both of j32- and Qs-adrenoceptor stimulating effects
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simultaneously in a range of usual dose can be used. For example, formoterol
(chemical name: 2-hydrogy-5-[(1RS)-1-hydrozy-2-[[(iRS)-2-(p-methoxyphenyl)-1-
methylethyl] aminolethyl7formanilide) can be illustrated.
The compounds having selective stimulating effects on both (3a- and (3s-
5 adrenoceptors are preferable. In the EC50 ratio of N-adrenoceptor
stimulating
effect to 03-adrenoceptor stimulating effect, the values ranging from about
1/100 to
100/1 are preferable, and those ranging from about 1/10 to 10/1 are more
preferable.
Usually, ECSO values for j3a-adrenoceptor stimulating effects can be
calculated by measuring inhibitory effects on spontaneous uterine contractions
of
pregnant rat. For example, EC50 value for formoterol was 4.2 x 10'20(M).
Usually, EC50 values for (3g-adrenoceptor stimulating effects can be
calculated by measuring inhibitory effects on spontaneous contractions of
ferret
ureteral smooth muscle. For example, EC50 value for formoterol was 5.1 x 10'8
(M).
The drugs having markedly weakened P1-adrenoceptor stimulating effects
are preferred to reduce burdens on heart and not to induce side effects such
as
tachycardia.
Example
The present invention is further illustrated in more detail by way of the
following Examples. The present invention is not limited thereto.
Measurement of the contractile force of the ureteral smooth muscle strip
(1) Preparation of smooth muscle strips
Specimens of human ureter were obtained from patients undergoing
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nephrectomy or total cystectomy. After the specimens were carefully dissected
free
from the surrounding fat tissues, they were cut into spiral stripic. The
ureteral
strips of about 20 mm in length and 5 mm in width were prepared.
(2) Experimental conditions
Buffer solution; Locke's-solution No.2 : NaC1 (154 mM), KCl (5.6 mM), CaC12
(2.1 mM), NaHCOs (5.6 mM) and glucose (3.6 mM)
Ureteral muscle strips without any spontaneous rhythmic contractions were
used. An initial resting tension of about 1.0 g was placed. The actions of
drugs
against the 40 mM KCl-induced tonic contraction were evaluated in the presence
of 10-6 M phentolamine.
The condition for measurement; The bathing solution was maintained at 37 C
and gassed with a mixture of 95 % 02 and 5 % CO2.
Drug treatment; The drug solution was added cumulatively to the organ bath
every 5 minutes.
The evaluation of drugs; The drug-induced relaxation was expressed as a
percentage of the maximal relaxing response to 10-5 M of isoproterenol. The
ureteral tension before the treatment is indicated as 100 %, and the tension
after
treatment of 103 M of isoproterenol which produces maximal ureteral relaxation
is
indicated as 0 %.
Eaample 1
According to the methods described above, the ureteral relaxing effects of the
drug were measured using the human ureteral smooth muscle strips.
Drugs: 1. isoproterenol, 2. procaterol and 3. CGP-12,177Ahydrochloride
The results are as follows (Fig.l): CGP-12,177A, a selective Jls-adrenoceptor
stimulant, as well as procaterol, a selective Ra-adrenoceptor stimulant,
produced
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~i-
apparent ureteral relaxation. Moreover, isoproterenol, a non-selective
adrenoceptor stimulant, which stimulates both R2- and 53-adrenoceptors, also
showed a more potent relaxing effect. These results demonstrate that the
relaxation of human ureteral smooth muscle is mediated via (3s-adrenoceptors
in
addition to Pz-adrenoceptors.
Example 2
According to the method described above, the interaction between ap-
adrenoceptor stimulant and aP-adrenoceptor blocker was evaluated in human
ureteral smooth muscle strips using the following drugs.
Drugs: 1. isoproterenol and 2. ICI-118,551 hydrochloride
The results are as follows (Fig. 2): The pre-treatment with ICI-118,551
(100nM),
a selective Pa adrenoceptor blocker, attenuated the isoproterenol-induced
ureteral
relaxation, but did not completely block. Isoproterenol still produced a
relaxation
by about 50 %, even if 100 nM of ICI-118,551 was present. To judging from
these
results, it is also demonstrated that the relaxation of human ureteral smooth
muscle is mediated via (3s-adrQnoceptora in addition to Aa-adrenoceptors and
that
considerable numbers of P3-adrenoceptors exist in human ureteral smooth
muscle.
Example 3
The experiment for measuring the Pz-adrenoceptor stimulating effect
(The effects of the drug on the spontaneous contraction in the isolated uterus
of
the pregnant rat)
The uterus of pregnant SD rats (pregnancy day of 21) was isolated and
longitudinal smooth muscle strips ( about 15 mm in length and fi mm in width)
free from the basal plate were prepared. The experiment was conducted
according
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S
to the Magnus method. The preparations were mounted with an initial resting
tension of about 1.0 g in the Locke's-Ringer solution maintained at 37 C and
gassed with a mixture of 95 % 02 and 5 % COa. The spontaneous contraction of
the
uterus was measured by an isometric force-transducer and recorded in a
rectigraph. The drug solution was added cumulatively to the organ bath every 5
minutes. Uterine activities were calculated as the sum of the amplitudes of
the
spontaneous contraction for 5 minutes, and the percent change before and after
the drug application were compared. The ECso value was determined as the molar
concentration required to produce 50 % of own marimal relaxation elicited by
each
drug.
Esample 4
The experiment for measuring the P8-adrenoceptor stimulating effects
(The effects of the drug on the spontaneous rhythmic contraction in the
isolated
ferret ureter)
The ferret ureter was isolated and the ring smooth muscle strips were prepared
(about 20 mm in length). The experiment was conducted according to the Magnus
method. The preparations were mounted with an initial resting tension of about
0.5 g in the Krebs-Henseleit solution maintained at 37 C and gassed with a
mixture of 95 % 02 and 5 % COa. The spontaneous contraction of the ureter was
measured by an isometric force-transducer and recorded in a rectigraph. The
drug
solution was added cumulatively to the organ bath every 5 minutes. Ureteral
activities were calculated as the sum of the amplitudes of the spontaneous
contraction for 5 minutes, and the percent change before and after the drug
application were compared. The EC6O value was determined as the molar
concentration required to produce 50 % of own mazimal relaxation elicited by
each
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drug.
Industrial Applicability
A drug which contains as the active ingredient a drug having the
stimulating effects on both ~2- and ps-adrenoceptors of the prcsent invention
exerts a potent relaxing effect on human ureteral smooth muscle, and is
suitable
as a drug for relieving pain and promoting the removal of calculi in
urolithiasis.
