Hair loss abstract
A method for inhibiting hair loss and/or promoting hair growth
in chemotherapy and/or radiation therapy patients wherein the (R)-enantiomer
of 4-[[(cyanoimino)-[(1,2,2-trimethylpropyl)amino]methyl]amino]benzonitri-
le is administered prior to, simultaneous with and/or after chemotherapy
and/or radiation treatment.
Hair loss claims
What is claimed is:
1. A method for preventing or inhibiting chemotherapy-induced hair
loss or radiation-induced hair loss or for promoting hair growth
in a patient having chemotherapy-induced hair loss or radiation-induced
hair loss, which comprises administering to a human or other mammal
a therapeutically effective amount of the (R)-enantiomer of 4-[[(cyanoimino)[(1,2,2-trimethylpropyl)amino]methyl]amino]benzonitrile.
2. The method as defined in claim 1 wherein the (R)-enantiomer
is administered prior to, simultaneous with and/or subsequent to
chemotherapy and/or radiation therapy.
3. The method as defined in claim 1 wherein the (R)-enantiomer
is administered prior to chemotherapy and/or radiation therapy.
4. The method as defined in claim 1 wherein the (R)-enantiomer
is administered simultaneously with and/or subsequent to chemotherapy
and/or radiation therapy.
5. The method as defined in claim 1 wherein the (R)-enantiomer
is administered topically.
6. The method as defined in claim 1 wherein the (R)-enantiomer
is administered as a cream formulation, lotion formulation, liquid
formulation or ointment formulation.
7. The method as defined in claim 1 wherein the (R)-enantiomer
is administered systemically.
8. The method as defined in claim 1 for promoting hair growth in
a patient having chemotherapy-induced hair loss.
9. The method as defined in claim 1 for inhibiting chemotherapy-induced
hair loss.
10. The method as defined in claim 1 for promoting hair growth
in a patient having radiation-induced hair loss.
11. The method as defined in claim 1 for inhibiting radiation-induced
hair loss.
12. The method according to claim 1 wherein the (R)-enantiomer
is administered in conjunction with a chemotherapeutic agent which
is an antineoplastic agent selected from the group consisting of
a microtuble-stabilizing agent, a microtuble-disruptor agent, an
alkylating agent, an anti-metabolite, epidophyllotoxin, an antineoplastic
enzyme, a topoisomerase inhibitor, procarbazine, mitoxantrone, a
platinum coordination complex, a biological response modifier, a
growth inhibitor, a hormonal/antihormonal therapeutic agent and
a haematopoietic growth factor.
13. The method according to claim 1 wherein the (R)-enantiomer
is administered in conjunction with a chemotherapeutic agent which
is an antineoplastic agent selected from the group consisting of
an anthracycline drug, a vinca drug, a mitomycin, a bleomycin, a
cytotoxic nucleoside, a taxane, an epothilone, discodermolide, a
pteridine drug, a diynene, an aromatase inhibitor and a podophyllotoxin.
14. The method according to claim 1 wherein the (R)-enantiomer
is administered in conjunction with a chemotherapeutic agent which
is an antineoplastic agent selected from the group consisting of
paclitaxel, docetaxel, 7-O-methylthiomethyl-paclitaxel, 3'-tert-butyl-3'-N-tert-butyl-
oxycarbonyl-4-deacetyl-3'-dephenyl-3'-N-debenzoyl-4-O-methoxycarbonyl-pacl-
itaxel, C-4 methyl carbonate paclitaxel, epothilone A, epothilone
B, epothilone C, epothilone D, desoxyepothilone A, desoxyepothilone
B, [1S-[1R*,3R*(E),7R*,10S*,11R*,12R*, 16S*]]-7,11-dihydroxy-8,8,10,12,16-pe-
ntamethyl-3-[1-methyl-2-(2-methyl-4-thiazolyl)ethenyl]-4-aza-17-oxabicyclo-
[ 14.1.0]heptadecase-5,9-dione, [1S-[1R*,3R*(E),7R*,10S*,11R*,12R*,16S*]]--
3-[2-[2-(aminomethyl)-4-thiazolyl]-1-methylethenyl]-7,11-dihydroxy-8,8,10,-
12,16-pentamethyl-4,17-dioxabicyclo[14.1.0]heptadecane-5,9-dione,
doxorubicin, carminomycin, daunorubicin, aminopterin, methotrexate,
methopterin, dichloro-methotrexate, mitomycin C, porfiromycin, 5-fluorouracil,
6-mercaptopurine, gemcitabine, cytosine arabinoside, podophyllotoxin,
etoposide, etoposide phosphate, teniposide, melphalan, vinblastine,
vincristine, leurosidine, vindesine, leurosine, estramustine, cisplatin,
carboplatin, cyclophosphamide, bleomycin, tamoxifen, ifosamide,
hexamethyl melamine, thiotepa, cytarabin, idatrexate, trimetrexate,
dacarbazine, L-asparaginase, camptothecin, CPT-11, topotecan, ara-C,
bicalutamide, flutamide, leuprolide, a pyridobenzoindole, an interferon
and an interleukin.
15. The method is defined in claim 1 wherein the (R)-enantiomer
is administered in the form of a topical formulation comprising
ethanol, propylene glycol and water.
16. The method as defined in claim 15 wherein the ethanol/propylene
glycol/water are in a 60/30/10 proportion.
17. The method as defined in claim 1 wherein the (R)-enantiomer
is administered in an amount from about 0.01 to about 15% by weight
of said (R)-enantiomer.
18. The method as defined in claim 1 wherein the (R)-enantiomer
is administered in the form of ethanol/propylene glycol/water, 60/30/10,
in an amount to provide a 2% solution of the (R)-enantiomer.
19. The method as defined in claim 1 wherein the (R)-enantiomer
is administered in combination with one or more other hair growth
promoting agents.
20. The method as defined in claim 19 wherein said other hair growth
promoting agent is another potassium channel opener, a 5-.alpha.-reductase
inhibitor, an androgen blocker, betamethasone dipropionate, a corticosteroid,
scopolamine and/or cyproterone acetate.
21. The method as defined in claim 20 wherein the other potassium
channel opener is minoxidil, diazoxide, cromakalim and/or pinacidil;
the 5-.alpha.-reductase inhibitor is finasteride, terazosin HCl,
and/or doxaosin mesylate; the androgen blocker is 4-(5-methoxyheptyl)-hexahydro--
2(1H)-pentalenone; and the corticosteroid is hydrocortisone.
22. The method as defined in claim 21 wherein said other hair growth
promoting agent is a 5-.alpha.-reductase inhibitor.
23. The method as defined in claim 22 wherein the 5-.alpha.-reductase
inhibitor is finasteride.
Hair loss description
REFERENCE TO OTHER APPLICATIONS
[0001] This is a continuation-in-part of U.S. application Ser.
No. 09/447,002, filed Nov. 22, 1999, which is a continuation of
U.S. application Ser. No. 09/119,884, filed Jul. 21, 1998, now U.S.
Pat. No. 6,013,668, which takes priority from Provisional Application
No. 60/055,568, Aug. 13, 1997, and Provisional Application No. 60/071,364,
Jan. 15, 1998.
FIELD OF THE INVENTION
[0002] The present invention relates to a method for inhibiting
hair loss and/or promoting hair growth in chemotherapy patients
employing the (R)-enantiomer of 4-[ [(cyanoimino)[(1,2,2-trimethylpropyl)amino]methyl]a-
mino] benzonitrile or pharmaceutical compositions containing same.
BACKGROUND OF THE INVENTION
[0003] Potassium channel openers such as minoxidil (Upjohn), pinacidil
(Lilly) and diazoxide (Shiseido and Schering-Plough) are known for
their hair growth stimulating activity. Thus, U.S. Pat. Nos. 4,596,812
and 4,139,619 disclose use of minoxidil in the treatment of male
pattern baldness, alopecia areata and balding in females. U.S. Pat.
No. 4,057,636 discloses pinacidil. DE 3,827,467A discloses combinations
of minoxidil and hydrocortisone or retinoids.
[0004] U.S. Pat. No. 5,011,837 to Atwal et al discloses aryl cyanoguanidines
which possess potassium channel activating activity and are useful
therapy for hypertension and other cardiovascular disorders, for
various central nervous system disorders, kidney and urinary problems
as well as for the promotion of hair growth, for example in the
treatment of male pattern baldness (alopecia). These aryl cyanoguanidines
have the structure 1
[0005] and its possible tautomers 2
[0006] and 3
[0007] including pharmaceutically acceptable salts, wherein
[0008] R.sub.1 is alkyl, alkenyl, alkynyl, haloalkyl,
[0009] cycloalkyl, aryl, arylalkyl or cycloalkylalkyl;
[0010] R.sub.2 is 4
[0011] R.sub.3 and R.sub.4 are each independently selected form
-R.sub.2, hydrogen, alkyl, alkenyl, alkynyl, haloalkyl, halo, alkoxy,
--NHalkyl, --N-(alkyl).sub.2, --S-alkyl, --O-aryl-alkyl, --S-arylalkyl
or --S-aryl, --O-aryl, --NHaryl-alkyl, or R.sub.2 and R.sub.3 taken
together are a group which form a ring with the two carbon atoms
to which they are attached, which group is selected from 5
[0012] wherein
[0013] m=1 or 2,
[0014] n=3-5,
[0015] p=2-4,
[0016] X is 0, NR.sub.5, CH.sub.2; and
[0017] R.sub.5 is hydrogen or R.sub.1.
[0018] Example 1 of U.S. Pat. No. 5,011,837 discloses the preparation
of 4-[[(cyanoimino)-[(1,2,2-trimethylpropyl)amino] benzonitrile
6
[0019] in the form of its racemic mixture.
[0020] U.S. Pat. No. 6,013,668 discloses a method for promoting
hair growth in humans employing the (R)-enantiomer of 4-[[(cyanoimino)[(1,2,2--
trimethylpropyl)-amino] methyl]amino]benzonitrile.
[0021] PCT Application WO 92/02225 discloses a combination of a
potassium channel opener and a 5-.alpha.-reductase inhibitor for
promoting hair growth.
[0022] PCT Application WO 92/09259A discloses use of an androgen
blocker and a potassium channel activator for stimulation of hair
growth.
[0023] PCT Application WO 96/29988 discloses a topical formulation
containing minoxide or minoxidil in combination with a testosterone
5-.alpha. reductase inhibitor.
[0024] PCT Application WO 94/18936 discloses a method for promoting
hair growth employing a vasodilator such as minoxidil in combination
with estradiol and/or a 5-.alpha.-reductase inhibitor.
[0025] The use of minoxidil in cancer patients to decrease the
duration of baldness caused by chemotherapy is disclosed by Duvic,
M. et al, "A randomized trial of minoxidil in chemotherapy-induced
alopecia", J. Am. Acad Dermalol 1996; 35:74-8. Duvic et al
disclose that in patients treated with fluorouracil, doxorubicin
and cyclophosphamide a 2% topical solution of minoxdil administered
during chemotherapy and 4 weeks thereafter, did not prevent alopecia
but did decrease period of baldness.
[0026] Rodriguez, R. et al "Minoxidil (Mx) as a prophylaxis
of doxorubicin-induced alopecia", Annals of Oncology 5:769-770,
1994 discloses that a 2% topical solution of minoxidil was not effective
in preventing doxorubicin-induced alopecia.
[0027] Hussein, A. M., "Protection Against Cytosine Arabinoside-Induced
Alopecia By Minoxidil In A Rat Animal Model", Int. J. Dermatol.
Vol. 34(7); 470-3, 1995 discloses that minoxidil, when injected
locally, offered good local prevention against 1-B--D-arabinofurano-sylcytosine
but not cyclophosphamide-induced alopecia.
DESCRIPTION OF THE INVENTION
[0028] In accordance with the present invention, a method is provided
for preventing or inhibiting chemotherapy-induced or radiation therapy-induced
hair loss wherein a therapeutically effective amount of the (R)-enantiomer
of 4-[[(cyanoimino)[(1,2,2-trimethylpropyl)-amino] methyl]amino]benzonitrile,
(hereinafter "the (R)-enantiomer") is administered to
a human or other mammal.
[0029] In addition, in accordance with the present invention, a
method is provided for promoting hair growth in a patient undergoing
chemotherapy or radiation and/or having chemotherapy-induced hair
loss or radiation-induced hair loss, wherein a therapeutically effective
amount of the (R)-enantiomer is administered to the patient.
[0030] In carrying out the above methods, the (R)-enantiomer will
be administered to the patient prior to and/or simultaneously with
and/or subsequent to chemotherapy and/or radiation therapy.
[0031] The above (R)-enantiomer of the invention has the structure
I 7
[0032] The (R)-enantiomer will preferably be in substantially pure
form, that is, will be at least 99% pure (R)-enantiomer and will
at most contain 1% (S)-enantiomer.
[0033] The method of the present invention also includes the use
of pharmaceutical compositions containing the (R)-enantiomer and
a pharmaceutically acceptable carrier therefor.
[0034] The (R)-enantiomer may be prepared as described in U.S.
Pat. No. 6,013,668 which is incorporated herein by reference.
[0035] The (R)-enantiomer may be administered by itself or may
be administered prior to, simultaneous with or after the antineoplastic
agent used in chemotherapy, or prior to simultaneously with or after
radiation therapy. In a preferred embodiment of the present invention,
the (R)-enantiomer is administered prior to the antineoplastic agent
or radiation therapy.
[0036] As used herein, the term "simultaneous" means
that the antineoplastic agent or radiation therapy and the (R)-enantiomer
are administered within 24 hours, preferably 12 hours, more preferably
6 hours, and most preferably 3 hours, of each other.
[0037] The chemotherapeutic agent which may be employed with the
(R)-enantiomer may include any of the antineoplastic agents listed
in the Physician's Desk Reference.
[0038] As used herein, the phrase "radiation therapy"
includes, but is not limited to, x-rays or gamma rays which are
delivered from either an externally applied source such as a beam
or by implantation of small radioactive sources.
[0039] As used herein, the phrase "antineoplastic agent"
refers to compounds which prevent cancer cells from multiplying.
In general, the antineoplastic agents of this invention prevent
cancer cells from multiplying by: (1) interfering with the cell's
ability to replicate DNA, or (2) inducing apoptosis in the cancerous
cells.
[0040] Examples of antineoplastic agents which are suitable for
use in the methods of this invention include, but are not limited
to, microtuble-stabilizing agents such as the taxanes, for example,
paclitaxel (also known as Taxol.RTM.), docetaxel (also known as
Taxotere.RTM.), 7-O-methylthio-methylpaclitaxel (disclosed in U.S.
Pat. No. 5,646,176), 3'-tert-butyl-3'-N-tert-butyloxycarbonyl-4-deacetyl-3'-de-
phenyl-3'-N-debenzoyl-4-O-methoxycarbonyl-paclitaxel (disclosed
in U.S. Ser. No. 60/179,965 filed on Feb. 3, 2000, and example 17
herein), C-4 methyl carbonate paclitaxel (disclosed in WO 94/14787),
the epothilones, such as epothilone A, epothilone B, epothilone
C, epothilone D, desoxyepothilone A, desoxyepothilone B, [1S-[ 1R*,3R*(E),7R*,10S*,11R*,12-
R*,16S*]]-7,11-dihydroxy-8,8,10,12,16-pentamethyl-3-[1-methyl-2-(2-methyl--
4-thiazolyl)ethenyl]-4-aza-17-oxabicyclo[14.1.0]hepta-decane-5,9-dione
(disclosed in WO 99/02514), [1S-[ 1R*,3R*(E),7R*,10S*,11R*,12R*,16S*]]-3--
[2-[2-(aminomethyl)-4-thiazolyl]-1-methylethenyl]-7,11-di-hydroxy-8,8,10,1-
2,16-pentamethyl-4,17-dioxabi-cyclo[14.1.0]-heptadecane-5,9-dione
(disclosed in U.S. Ser. No. 09/506,481 filed on Feb. 17, 2000, and
examples 7 and 8 herein), and derivatives thereof; microtuble-disruptor
agents; alkylating agents; anti-metabolites; epidophyllotoxin; an
antineoplastic enzyme; a topoisomerase inhibitor; procarbazine;
mitoxantrone; platinum coordination complexes; biological response
modifiers; growth inhibitors; hormonal/antihormonal therapeutic
agents; and haematopoietic growth factors.
[0041] Other classes of antineoplastic agents suitable for use
in the method of the present invention include, but are not limited
to, the anthracycline family of drugs, the vinca drugs, the mitomycins,
the bleomycins, the cytotoxic nucleosides, discodermolide, the pteridine
family of drugs, diynenes, aromatase inhibitors, and the podophyllotoxins.
Particularly useful members of those classes not previously mentioned
include, for example, doxorubicin, carminomycin, daunorubicin, aminopterin,
methotrexate, methopterin, dichloro-methotrexate, mitomycin C, porfiromycin,
5-fluorouracil, 6-mercaptopurine, gemcitabine, cytosine arabinoside,
podophyllotoxin or podophyllotoxin derivatives such as etoposide,
etoposide phosphate or teniposide, melphalan, vinblastine, vincristine,
leurosidine, vindesine, leurosine, and the like. Other useful antineoplastic
agents include estramustine, cisplatin, carboplatin, cyclophosphamide,
bleomycin, tamoxifen, ifosfamide, melphalan, hexamethyl melamine,
thiotepa, cytarabin, idatrexate, trimetrexate, dacarbazine, L-asparaginase,
camptothecin, CPT-11, topotecan, ara-C, bicalutamide, flutamide,
leuprolide, pyridobenzoindole derivatives, interferons, and interleukins.
[0042] In carrying out the method of the invention, the (R)-enantiomer
may be formulation with other hair growth promoting compounds such
as the potassium channel openers minoxidil (Upjohn) and/or diazoxide
(Shiseido and Schering-Plough), as well as cromakalim and pinacidil;
a 5-.alpha.-reductase inhibitor such as finasteride (Merck's Proscar.RTM.),
terazosin HCl (Abbott's Hytrin.RTM.), or doxaosin mesylate (Pfizer's
Cardura.RTM.); and/or an androgen blocker such as 4-(5-methoxyheptyl)-hex-
ahydro-2(1H)-pentalenone as disclosed in PCT Application WO 92/09259A,
vasoconstrictors such as betamethasone dipropionate, corticosteroids
such as hydrocortisone, and scopolamine, and cyproterone acetate.
[0043] The (R)-enantiomer may be administered via topical, oral,
parenteral or rectal routes as described in U.S. Pat. No. 5,011,837
(incorporated herein by reference), with topical being preferred,
to humans or other mammals such as dogs and cats prior to, simultaneous
with and/or subsequent to chemotherapy and/or radiation therapy.
Thus, the (R)-enantiomer in suitable topical formulations is applied
to the skin region where hair growth is desired and/or where hair
loss is to be inhibited.
[0044] Typical topical formulations for use herein will include
conventional ointments, creams, lotions, waxes, gels, pastes, jellies,
sprays, aerosols and the like in aqueous or non-aqueous formulations.
Examples of suitable topical formulations are disclosed in U.S.
Pat. Nos. 4,139,619 and 4,596,812 which are incorporated herein
by reference.
[0045] The (R)-enantiomer will be used in an effective amount,
that is, in an amount sufficient to inhibit hair loss during chemotherapy
and/or radiation therapy and/or promote hair growth during and/or
subsequent to chemotherapy and/or radiation therapy, such that hair
growth is increased or produced. A typical topical composition will
include from about 0.01 to about 15% by weight, preferably from
about 0.1 to about 10% by weight of the composition.
[0046] The topical formulations containing the (R)-enantiomer of
the invention can be applied to the area to be treated such as the
scalp in humans, by spraying, dabbing or swabbing to deliver the
enantiomer to the region of the hair follicle. The formulations
will be applied to the area of treatment on a routine basis prior
to, during and subsequent to chemotherapy and/or radiation therapy,
at least once daily, and preferably two or more times daily.
[0047] The accompanying Figure is a graph showing the effect of
a once daily application of each of the (R)-and (S)-enantiomers
described herein on hair growth in male C3H mice.
[0048] The following Example describes the preparation of the (R)-enantiomer
and the (S)-enantiomer.
EXAMPLE 1
[0049] (R)-4-[[(Cyanoimino)[(1,2,2-trimethylpropyl)amino]-methyl]
amino]benzonitrile 8
[0050] A. (R)-1,2,2-Trimethylpropyl amine 9
[0051] The title compound was prepared according to the procedure
described by Manley and Quast (J. Med. Chem. 1992, 35, 2327-2340)
with some modification. A mixture of pinacolone (29 g, 290 mmol),
(R)-.alpha.-methylbenzyl amine (17.6 g, 145 mmol) and p-toluenesulfonic
acid monohydrate (300 mg) in toluene (150 mL) was refluxed using
a Dean-Stark trap (to remove water from the reaction mixture) for
3 days. The solvent was evaporated and the residue was distilled
at ca. 120-2.degree. C. (9 mm) to give 21 g (71% yield) of 10
[0052] as a colorless oil. This material was dissolved in anhydrous
THF (210 mL) and treated at 0-2.degree. C. with borane-THF complex
(1M, 206 mL, 206 mmol). The mixture was allowed to come to room
temperature, stirred for 5h and concentrated in vacuo. To the resulting
oily residue was carefully added ethanol (300 mL), and the mixture
was refluxed for 1h and concentrated again in vacuo. The residue
was chromatographed over basic alumina (activity grade 1/hexane)
giving colorless oil. Proton NMR and HPLC (YMC C18 S3 4.6X50 mm
column/water-MeOH--H.sub.3PO.sub.4 90:10:0.2 to 10:90:0.2 gradient)
indicated that this material was contaminated with ca. 10% of the
(S,R)-diastereomer. Therefore, this mixture was resubjected to flash
chromatography (silica gel/hexane-EtoAc-triethylamine 95:5:0.1)
to afford 11
[0053] (11.45 g, 55.8 mmol, 54% yield). The above compound (11.45
g) and 10% palladium on carbon (1.5 g) were taken in EtOH (230 mL)
and stirred under hydrogen for 12 hours. The mixture was filtered
and the filtrate (ca. 230 mL) containing the title product was used
as such for the next step as a ca. 0.24 M solution in ethanol (assumed
100% yield).
[0054] B. N-Cyano-N'-(4-cyanophenyl)thiourea, monosodium salt 12
[0055] The title compound was prepared according to Example 1 Part
A of U.S. Pat. No. 5,011,837.
[0056] C. (R)-4-[[(Cyanoimino)[(1,2,2-trimethyl-propyl)amino] methyl]amino]benzonitrile
13
[0057] To a solution of Part B compound (6.0 g, 26.8 mmol) in DMF
(150 mL) was sequentially added the solution of Part A compound
(ca. 0.24 M in EtOH, 112 mL, 26.8 mmol) and 1-(3-dimethylamino-propyl)-3-ethylcarbodiimi-
de hydrochloride (WSC) (6.0 g, 31.3 mmol). The mixture was stirred
at room temperature for 3 hours, diluted with ethyl acetate and
sequentially washed with 1N HC1, water and brine. The organic layer
was dried over magnesium sulfate, concentrated and the crude product
was purified by flash chromatography on silica gel (hexanes-ethyl
acetate-triethylamine 75:25:0.2) to afford a colorless foam. This
material was recrystallized from isopropanol to give the title compound
as a white solid (4.15 g, 57.6%), mp 159-60.degree. C.; [.alpha.].sub.D-180.degree.
C.=1, MeOH; enantiomeric purity determined by chiral HPLC=99% (ChiralPak
AD column/hexane-isopropanol-triethylamine 80:20:0.2); MS: 270 (M+H).sup.+;
.sup.1H NMR (CDCl.sub.3) .delta. 8.65 (br s, 1H), 7.69 (d, 2H, J=8.79
Hz), 7.37 (d, 2H, J=8.79 Hz), 4.93 (br d, 1H), 3.83 (m, 1H), 1.10
(d, 1H, J=6.45 Hz), 0.90 (s, 9H).
[0058] Elemental analysis: calculated for C.sub.15H.sub.19N.sub.5:
[0059] C, 66.89; H, 7.11; N, 26.00
[0060] Found: C, 66.71; H, 7.14; N, 25.98.
EXAMPLE 2
[0061] (S)-4-[[(Cyanoimino)[(1,2,2-trimethylpropyl)amino]-methyl]
amino]benzonitrile 14
[0062] The title compound was prepared from Part B compound of
Example 1 and (S)-1,2,2-trimethylpropyl amine (prepared according
to Manley and Quast, J. Med. Chem., 1992, 35, 2327-2340) by the
same procedure as described in Example 1, Part C. The product was
obtained as a colorless solid, mp 158-59.degree. C.; [a].sub.D+189.degree.
C.=1, MeOH; enantiomeric purity determined by chiral HPLC=99.4%
(ChiralPak AD column/hexane-isopropanol-triethylamine 80:20:0.2);
MS: 270 (M+H).sup.+; .sup.1H NMR (CDCl.sub.3) .delta. 8.43 (br s,
1H), 7.69 (d, 2H, J=8.79 Hz), 7.37 (d, 2H, J=8.79 Hz), 4.93 (br
d, 1H), 3.83 (m, 1H), 1.10 (d, 1H, J=6.45 Hz), 0.90 (s, 9H).
EXAMPLE 3
[0063] Comparison of Example 1-(R)-Enantiomer and Example 2-(S)-Enantiomer
Re Hair Growth in an Animal Model
[0064] The objective of the following described experiment was
to compare and evaluate the in vivo effect of the Example 1-(R)-enantiomer
and the Example 2-(S)-enantiomer on hair growth in an animal model.
The two enantiomers were compared topically for hair growth in C3H
mice.
[0065] Animal Model
[0066] The C3H mouse is a useful model for studying hair growth.
Its usefulness rests with the fact that skin pigmentation of this
animal is provided by the melanocytes of the hair follicle and not
the epidermis. In the telogen or the resting phase of the hair follicle,
the skin is pink. In the earliest phase of anagen or the growth
phase, there is sudden graying of the skin and as the anagen phase
progresses the skin becomes darker in color. In this study, visual
observation was used as an in vivo assay of anagen induction. Furthermore
as anagen develops, the skin thickness increases from a thin telogen
skin to a measurably thickened anagen skin. Thus, recording the
skin color and microscopic thickness of skin from these mice offers
a sensitive, quantifiable and convenient method of assessing the
phases of hair growth.
[0067] Groups of 20, six to seven week old male C3H mice with hair
follicles in the resting phase of hair growth were used. At this
stage in their life, the hair follicles remain in the telogen phase
for up to 30 days or longer. This provides an adequate window of
time to screen drugs. Compounds that improve hair growth stimulate
the hair follicles from the telogen to the anagen phase. This stimulation
is manifested by the shortening of the telogen phase of the hair
follicle cycle.
[0068] Animals were anesthetized with ketamine/rompun (100 mg/Kg
and 12 mg/Kg) IP and the hair over a defined dorsal area were closely
clipped.
[0069] Animals with pink skin were treated topically 1.times. daily,
5 days per week with 50 microliters of a 2% solution of Example
1-(R)-enantiomer and a 2% solution of Example 1-(S)-enantiomer or
vehicle by itself, applied to the dorsal area. The vehicle employed
was ethanol/propylene glycol/water, 60/30/10. Treatment was continued
for at least 4-5 weeks.
[0070] Animals were observed daily for side effects and changes
to the test sites. All observations were documented. Test sites
were graded weekly for changes in skin color and hair growth. In
this study drug effects were evaluated using the visual observation
of skin changing from pink to gray and resulting in hair growth.
[0071] Results
[0072] The percent of animals that induced hair follicle stimulation
during the treatment period is illustrated in the accompanying Figure
below. The most significant observation made between the two enantiomers
is the difference in the time of onset of follicle stimulation.
The time of onset for the Example 1-(R)-enantiomer was day 7 compared
to day 11 for Example 2-(S)-enantiomer. The time of onset for the
vehicle control was day 28. By day 11 of treatment the Example 1-(R)-enantiomer
caused hair follicle stimulation in 40% of the test mice compared
to only 5% with Example 2-(S)-enantiomer. By day 14, 50% of the
animals treated with Example 1-(R)-enantiomer showed hair follicle
stimulation compared to 25% for Example 2-(S)-enantiomer. By day
28, 85% of the animals treated with the Example 1-(R)-enantiomer
showed hair follicle stimulation as compared to 65% treated with
Example 2-(S)-enantiomer. Thus throughout the treatment period,
the group treated with Example 1-(R)-enantiomer showed a higher
incidence of hair follicle stimulation as compared to the group
treated with Example 2-(S)-enantiomer.
[0073] The attached Figure shows the effect of 1.times. daily topical
application of Example 1-(R)-enantiomer and Example 2-(S)-enantiomer.
[0074] In conclusion, these results in the C3H mice indicate that
there is a remarkable difference between the Example 1-(R)-enantiomer
and the Example 2-(S)enantiomer in their effect on hair follicle
stimulation; in particular the (R)-enantiomer has a faster onset
of action compared to the corresponding (S)-enantiomer.
[0075] These results are indeed surprising and unexpected especially
in view of the vasorelaxant potencies of each of these enantiomers,
which is generally recognized as an indication of hair growth promoting
properties (Side Effects of Vasodilator Therapy, W. A. Pettinger
et al, Hypertension, 1988, Vol. 11, II-34 to II-36, and Minoxidil
Stimulates Cutaneous Blood Flow in Human Balding Scalps: Pharmacodynamics
measured by laser Doppler velocimetry and photopulse plethysmography.
R. C. Wester et al, J. Invest. Dermatol., 184, Vol. 82, 515-517).
[0076] Thus, while the IC.sub.50 for vasorelaxant potency of the
(R)-enantiomer is 47.+-.17 nM versus 157.+-.35 nM for the (S)-enantiomer,
as seen above, the hair growth promoting ability of the (R)-enantiomer
for producing hair growth within 11 days of treatment is 8 times
greater than the corresponding (S)-enantiomer. |