Ex Parte Motwani et al

Patent Trial and Appeal Board

Feb 21, 2017

13320169 (P.T.A.B. Feb. 21, 2017)

United States Patent and Trademark Office
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O.Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
13/320,169 06/25/2012 Sanjay Kumar Motwani RLL-l 176.1US 8568
26815 7590
Sun Pharma
Intellectual Property Department
2 Independence Way
PRINCETON, NJ 08540
EXAMINER
PAGONAKIS, ANNA
ART UNIT PAPER NUMBER
1628
NOTIFICATION DATE DELIVERY MODE
02/23/2017 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
general.ip.mailbox@sunpharma.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte SANJAY KUMAR MOTWANI, SHASHIKANTH P. ISLOOR,
and VINOD ARORA1
Appeal 2015-007524
Application 13/320,169
Technology Center 1600
Before ERIC B. GRIMES, RYAN H. FLAX, and DAVID COTTA,
Administrative Patent Judges.
GRIMES, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134 involving claims to topical
compositions, which have been rejected for lack of written description,
anticipation, obviousness, and obviousness-type double patenting. We have
jurisdiction under 35 U.S.C. § 6(b).
We reverse and enter a new ground of rejection.
1 Appellants identify the Real Party in Interest as Ranbaxy Laboratories
Limited. (Appeal Br. 3.)
Appeal 2015-007524
Application 13/320,169
STATEMENT OF THE CASE
Acne lesions are associated with infection by Propionibacterium
acnes. (Spec. 1:6—14.) “A treatment option for acne is retinoids” and “oral
isotretinoin was established in the last decade as the gold standard of acne
therapy” but it has potentially serious side effects. {Id. at 2:4—14.)
“[RJetinoid formulations when administered topically would certainly
represent an improvement with regard to the risk of possible side effects.”
{Id. at 2:19—20.) “Retinoids are insoluble or at most very slightly soluble in
water, but readily soluble in, e.g., ethanol. Therefore retinoid containing
preparations have been most effectively applied using an alcohol containing
carrier system, which causes an uncomfortable burning sensation by itself.”
{Id. at 3:3—6.) The Specification discloses an alcohol-free topical
composition comprising a retinoid such as isotretinoin. {Id. at 4:12—21.)
Claims 1, 5—7, 10, 13, and 17—19 are on appeal. Claims 1 and 13 are
the independent claims and read as follows:
1. A topical composition in the form of an unencapsulated solution for
applying to the skin of a human having a skin infection to treat the skin
infection, the topical composition comprising:
(i) a therapeutically effective amount of isotretinoin or its
pharmaceutically acceptable salts thereof as the sole active ingredient, the
isotretinoin being present at a concentration from 0.001% to 1.5% by weight
per volume of the total composition;
(ii) a pharmaceutically acceptable vehicle in which the therapeutically
effective amount of isotretinoin is soluble; and
(iii) one or more pharmaceutically acceptable excipients, wherein the
composition is free of ethyl alcohol.
2
Appeal 2015-007524
Application 13/320,169
13. A topical composition in the form of an unencapsulated solution for
applying to the skin of a human having a skin infection to treat the skin
infection, the topical composition comprising:
(i) a therapeutically effective amount of isotretinoin or its
pharmaceutically acceptable salts thereof, the isotretinoin being present at a
concentration from 0.001% to 1.5% by weight per volume of the total
composition;
(ii) a pharmaceutically acceptable vehicle;
(iii) one or more pharmaceutically acceptable excipients; and
(iv) an additional active ingredient selected from the group consisting
of antibiotics, bactericidal drugs, bacteriostatic drugs and anti-infective
agents
wherein the composition is free of ethyl alcohol.
The claims stand rejected as follows:
Claims 1, 5—7, 10, 13, and 17—19 under 35 U.S.C. § 112, first
paragraph, for lack of adequate written description (Ans. 2);
Claims 13 and 17—19 under 35 U.S.C. § 102(b) as anticipated by
Nagy2 (Ans. 4);
Claims 1, 5—7, 10, 13, and 17—19 under 35 U.S.C. § 103(a) as obvious
based on Jarosz3 and Ashley4 (Ans. 5); and
Claims 1, 5—7, and 10, provisionally, for obviousness-type double
patenting based on the claims of application 13/320,164 (Ans. 9).
2 Nagy et al., US 5,252,604, issued Oct. 12, 1993.
3 Jarosz, EP 0 184 942, published June 18, 1986.
4 Ashley, US 7,211,267 B2, issued May 1, 2007.
3
Appeal 2015-007524
Application 13/320,169
I
The Examiner has rejected all of the claims on appeal as lacking
adequate written description in the Specification. The Examiner finds that,
although the Specification describes compositions that are “alcohol-free,” it
does not describe compositions that are free of ethyl alcohol specifically, as
recited in the claims. (Ans. 2—3.)
Appellants argue that the Specification describes retinoids as soluble
in ethyl alcohol, but states that such “alcohol” carrier systems cause skin
irritation and should be avoided, and also describes certain alcohols (e.g.,
fatty alcohols and benzyl alcohol) as possible vehicles or preservatives.
(Appeal Br. 8.) Appellants argue that “one of ordinary skill in the art
reading the application would readily conclude that Applicant’s use of
alcohol is meant to be synonymous with ethanol.” {Id. at 11.)
We agree with Appellants that the claim language is consistent with
the Specification’s discussion of the solubility of retinoids in ethanol and the
drawback of using “an alcohol containing carrier system” (Spec. 3:3—6),
with the resulting need for an “alcohol-free” composition {id. at 4:7—8). We
also note that the Specification includes exemplary compositions that do not
contain ethanol. {Id. at 11—12.) A person of ordinary skill in the art
therefore would have understood that Appellants were in possession of the
claimed invention at the time this application was filed.
II
The Examiner has rejected claims 13 and 17—19 as anticipated by
Nagy. The Examiner finds that “Nagy et al. teach a liquid composition
suitable for topical administration comprising retinoic acid such as
4
Appeal 2015-007524
Application 13/320,169
isotretinoin and alpha tocopherol (claim 1 and Example 2e). Alpha
tocopherol behaves as an antiinflammatory compound to reduce the
inflammation caused by the retinoid.” (Ans. 4.) The Examiner finds that
Nagy’s Example 2e composition also contains water (a carrier) and not ethyl
alcohol. (Id.)
Claim 13, however, also requires “an additional active ingredient
selected from the group consisting of antibiotics, bactericidal drugs,
bacteriostatic drugs and anti-infective agents.” The Examiner has not
pointed to any of the recited types of active agents in any of Nagy’s
Example 2e composition. The Examiner, therefore, has not shown that
claim 13, or dependent claims 17—19, are anticipated by Nagy. See In re
Skvorecz, 580 F.3d 1262, 1266 (Fed. Cir. 2009) (“Anticipation requires that
all of the claim elements and their limitations are shown in a single prior art
reference.”). We therefore reverse the anticipation rejection.
Ill
The Examiner has rejected all of the claims on appeal as obvious
based on Jarosz and Ashley. The Examiner finds that Jarosz discloses
treating acne using capsules containing isotretinoin,5 a vehicle, BHA (an
antioxidant), and no ethanol. (Ans. 5—6.) The Examiner finds that Ashley
teaches treating acne with an antibiotic. (Id. at 7.) The Examiner concludes
that it would have been obvious to administer Ashley’s antibiotic in
combination with Jarosz’s isotretinoin because both agents are disclosed to
be useful in treating acne. (Id.)
5 Isotretinoin is also known as 13-cis vitamin A acid. (Spec. 2:6.)
5
Appeal 2015-007524
Application 13/320,169
Appellants argue, among other things, that the Examiner erred in
concluding that “one of skill in the art reading Jarosz would reduce the
amount of isotretinoin from 3 to 12% by weight to 0.001 to 1.5% w/v.
Jarosz does not provide a motivation for reducing the amount of isotretinoin
present.” (Appeal Br. 18.) Appellants also argue that Ashley does not make
up for this deficiency. (Id. at 19.)
We agree with Appellants that the Examiner has not shown that the
cited references would have made obvious a composition that includes
isotretinoin at a concentration of 0.001% to 1.5% by weight per volume of
the composition, as required by the claims on appeal. Jarosz discloses oral
dosage forms that contain isotretinoin, where “the active ingredient is
present in a ratio between 3 and 12% by weight.” (Jarosz 2:35—36, 2:43.)
Jarosz therefore requires a minimum of about twice as much isotretinoin in
its composition as the maximum amount recited in the claims.
The Examiner reasons that “[t]he variation in the dosage amounts is a
matter [that] was well within the skill of the artisan at the time of the
invention and would not have required undue experimentation or have been
outside the realm of knowledge generally available to the skilled artisan.”
(Ans. 8.) However, Jarosz’s composition is intended for oral administration
(Jarosz 2:36—38), whereas the claimed composition is intended for topical
administration. The Examiner has not pointed to evidence showing that
these routes of administration require similar amounts of isotretinoin to be
therapeutically effective.
In short, the fact that a skilled worker could have reduced by half the
concentration of isotretinoin in Jarosz’s composition, is not an adequate
6
Appeal 2015-007524
Application 13/320,169
reason for concluding that it would have been obvious to do so.
‘“[R]ejections on obviousness grounds cannot be sustained by mere
conclusory statements; instead, there must be some articulated reasoning
with some rational underpinning to support the legal conclusion of
obviousness.’” KSRInt’l Co. v. Teleflex Inc., 550 U.S. 398, 418 (2007). We
therefore reverse the rejection under 35 U.S.C. § 103(a).
IV
The Examiner has provisionally rejected claims 1, 5—7, and 10 for
obviousness-type double patenting based on application 13/320,164. The
Examiner acknowledges that the claims of the ’ 164 application “recite that
the solution contains about 6 mg of isotretinoin per ml of the carrier,” but
concludes that the “copending application and the instant application are
claiming common subject matter” because “[t]he variation in the dosage
amounts is a matter was well within the skill of the artisan at the time of the
invention and would not have required undue experimentation or have been
outside the realm of knowledge generally available to the skilled artisan.”
(Ans. 9.)
Appellants argue that
the claims of the pending application and co-pending
Application No. 13/320,164 are different by at least: (a)
differences in the concentration or strength (6 mg isotretinoin per
ml carrier versus about 0.001% to 1.5%), and (b) differences in
the route of administration (oral versus topical). For at least these
reasons, the obviousness type double patenting rejection should
be withdrawn.
(Appeal Br. 23.)
7
Appeal 2015-007524
Application 13/320,169
For the same reason as discussed above with respect to the § 103
rejection, we agree with Appellants that the Examiner has not provided an
adequate basis for concluding that the instant claims and those of the ’ 164
application define inventions that are obvious variants of each other. We
therefore reverse the provisional rejection for obviousness-type double
patenting.
V
Under the provisions of 37 C.F.R. § 41.50(b), we enter the following
new ground of rejection: Claims 1 and 13 are rejected under 35 U.S.C.
§ 102(b) as anticipated by Nagy.
With respect to claim 1, Nagy discloses a composition (Example 2f)
that contains 0.05—1.00 wt% isotretinoin, propylene glycol
dicaprylate/dicaprate, and vitamin E. (Nagy 5:55—68.) The composition
does not include ethanol. Nagy states that vitamin E is an antioxidant.
(Nagy 1:30-32.) Appellants’ Specification states that pharmaceutically
acceptable excipients include antioxidants. (Spec. 8:28—29.) Appellants’
Specification also states that propylene glycol dicaprylate/dicaprate is a
vehicle. {Id. at 6:24 to 7:10.) Although Nagy states the concentration of
isotretinoin in % by weight rather than “% by weight per volume” as in
claim 1, its Example 2f composition reasonably appears to include all of the
components of the claimed composition. See In re Spada, 911 F.2d 705, 708
(Fed. Cir. 1990) (“[Wjhen the PTO shows sound basis for believing that the
products of the applicant and the prior art are the same, the applicant has the
burden of showing that they are not.”).
8
Appeal 2015-007524
Application 13/320,169
With respect to claim 13, Nagy’s composition (Example 2f) also
includes hexetidine. (Nagy 5:65.) Hexetidine is an antibacterial agent.
(Tauscher6 1:18—20 (“1,3-bis(P-ethylhexyl)-5-amino-5-methyl
hexahydropyrimidine, hereinafter referred to as ‘hexetidine’, has a
remarkable antibacterial activity.”).) An antibacterial agent is an “anti-
infective agent,” as recited in claim 13. (Spec. 10:28—29.) Thus, Nagy’s
Example 2f composition reasonably appears to include all of the components
of instant claim 13.
SUMMARY
We reverse all of the rejections on appeal. We enter a new ground of
rejection of independent claims 1 and 13. We leave it to the Examiner, upon
return of this application to the examining corps, to determine whether the
dependent claims should be rejected for anticipation or obviousness based
on the prior art.
TIME PERIOD FOR RESPONSE
This decision contains a new ground of rejection pursuant to
37 C.F.R. § 41.50(b). Section 41.50(b) provides “[a] new ground of
rejection pursuant to this paragraph shall not be considered final for judicial
review.” Section 41.50(b) also provides:
When the Board enters such a non-final decision, the appellant,
within two months from the date of the decision, must exercise
one of the following two options with respect to the new ground
of rejection to avoid termination of the appeal as to the rejected
claims:
6 Tauscher et al., U.S. Patent 3,946,013, issued Mar. 23, 1976.
9
Appeal 2015-007524
Application 13/320,169
(1) Reopen prosecution. Submit an appropriate
amendment of the claims so rejected or new Evidence relating to
the claims so rejected, or both, and have the matter reconsidered
by the examiner, in which event the prosecution will be
remanded to the examiner. The new ground of rejection is
binding upon the examiner unless an amendment or new
Evidence not previously of Record is made which, in the opinion
of the examiner, overcomes the new ground of rejection
designated in the decision. Should the examiner reject the claims,
appellant may again appeal to the Board pursuant to this subpart.
(2) Request rehearing. Request that the proceeding be
reheard under § 41.52 by the Board upon the same Record. The
request for rehearing must address any new ground of rejection
and state with particularity the points believed to have been
misapprehended or overlooked in entering the new ground of
rejection and also state all other grounds upon which rehearing
is sought.
Further guidance on responding to a new ground of rejection can be
found in the Manual of Patent Examining Procedure § 1214.01.
REVERSED; 37 C.F.R, $ 41.50(b)
10
Notice of References Cited
Application/Control No.
13/320,169
Applicant(s)/Patent Under
Reexamination
Sanjay Kumar Motwani et al.
Examiner
Anna Pagonakis
Art Unit
1600
Page 1 of 1
U.S. PATENT DOCUMENTS
*
DOCUMENT NO. DATE NAME CLASS SUBCLASS
DOCUMENT
SOURCE **
APS OTHER
□ A 3,946,013 03/23/76 Tauscher et al. □ □
□ B □ □
□ C □ □
□ D □ □
□ E □ □
□ F □ □
□ G □ □
□ H □ □
□ 1 □ □
□ J □ □
□ K □ □
□ L □ □
□ M □ □
FOREIGN PATENT DOCUMENTS
*
DOCUMENT NO. DATE COUNTRY NAME CLASS SUBCLASS
DOCUMENT
SOURCE**
APS OTHER
□ N □ □
□ O □ □
□ P □ □
□ Q □ □
□ R □ □
□ S □ □
□ T □ □
NON-PATENT DOCUMENTS
* DOCUMENT (Including Author, Title Date, Source, and Pertinent Pages)
DOCUMENT
SOURCE **
APS OTHER
□ U □ □
□ V □ □
□ w □ □
□ X □ □
*A copy of this reference is not being furnished with this Office action. (See Manual of Patent Examining Procedure, Section 707.05(a).)
**APS encompasses any electronic search i.e. text, image, and Commercial Databases.
U.S. Patent and Trademark Office
PTO-892 (Rev. 03-98Notice of References Cited Part of Paper No. 16
United States Patent mi 3,946,013
Tauscher et al. [45] Mar. 23, 1976
[54] l,3-BIS(BETA-ETHYLHEXYL)-5-AMINO-5-
METHYLHEXAHYDROPYRIMIDINE-
PYRIDINE-3-CARBOXYLATE, PROCESS
FOR ITS PREPARATION AND
PHARMACEUTICAL COMPOSITIONS
CONTAINING THIS COMPOUND
[75] Inventors: Manfred Tauscher; Joachim Giiring,
both of Gronau; Wolfgang Busch,
Alfeld; Oskar Rohte, Kheden, all of
Germany
[73] Assignee: Johann A. Wulfing, Dusseldorf and
Neuss, Germany
[22] Filed: Feb. 28, 1974
[21] Appl. No.: 446,925
[30] Foreign Application Priority Data
Mar. 1, 1973 Germany.............................. 2310337
Mar. 1, 1973 Germany.............................. 2310338
[52] U.S. Cl............................ 260/256.4 N; 424/251
[51] Int. Cl.2......................................... C07D 239/04
[58] Field of Search..............260/256.4 N, 256.4 H,
260/256.4 B
[56] References Cited
UNITED STATES PATENTS
3,278,536 10/1966 Elslager et al................. 260/256.4 B
3,749,721 7/1973 Herrmann et al............. 260/256.4 H
Primary Examiner—Richard J. Gallagher
Assistant Examiner—James H. Turnipseed
Attorney, Agent, or Firm—Kenyon & Kenyon
[57] ABSTRACT
l,3-bis(/3-ethylhexyl)-5-amino-5-methylhexahy-
dropynmidine pyridine-3-carboxylate(hexetidine nico-
tinate), which has greater bacteriostatic activity and
lower toxicity in comparison with hexetidine or other
salts of hexetidine, is prepared by reacting hexetidine
or an acid addition salt thereof with nicotinic acid in
an organic solvent.
1 Claim, No Drawings
1
3,946,013
l,3-BIS(BETA-ETHYLHEXYL)-5-AMINO-5-
METHYLHEXAHYDROPYRIMIDINE-PYRIDINE-3-
CARBOXYLATE, PROCESS FOR ITS
PREPARATION AND PHARMACEUTICAL
COMPOSITIONS CONTAINING THIS COMPOUND
The present invention pertains to a novel antibacte­
rial compound, to a process for its preparation and to
pharmaceutical compositions containing it. More par­
ticularly, this invention is concerned with l,3-bis(/3-
ethylhexyl)-5-amino-5-methylhexahydropyrimidine
pyridine-3-carboxylate, hereinafter referred to as “hex-
etidine nicotinate”, a process for its preparation and
pharmaceutical compositions containing it.
It is known from studies of Witold Saski and S. G.
Shah (Journal of Pharmaceutical Science, 54, 277-280
(1965) that l,3-bis(j3-ethylhexyl)-5-amino-5-methyl-
hexahydropyrimidine, hereinafter referred to as “hex-
etidine”, has a remarkable antibacterial activity. F. A.
Barkley, F. J. Turner, R. S. Pianotti, P. L. Carthage and
B. S. Schwartz (in Antimicrobial Agents Annual
507-519 (1960/1961) report that the salt formation of
hexetidine with organic acids sometimes enhances this
activity.
Surprisingly it was now found that a hitherto un­
known salt of hexetidine, namely l,3-bis(/3-ethylhex-
yl)-5-amino-5-methylhexahydropyrimidine pyridine-3-
carboxylate or “hexetidine nicotinate”, shows a partic­
ularly favorable increase in antibacterial activity and is
therefore specially suited as active compound in phar­
maceutical compositions. Hexetidine nicotinate is rep­
resented by the structural formula:
2
ratio of about 1:1, the reaction mixture is cooled and
the precipitated hexetidine nicotinate is recovered. If
the hexetidine compound used as the starting material
does not have the desired purity this salt formation
5 reaction may also be employed for purifying crude
hexetidine.
In the synthesis of hexetidine a number of by-pro­
ducts are formed, totalling about 20 percent by weight.
Such compounds mainly comprise N„ N3-bis(ethylhex-
10 yl)-2-methyl-1,2,3-propane triamine and 2,6-bis(/3-
ethylhexyl)-hexahydro-7a-methyl-lH-imidazo-( 1,5-
e)imidazole as well as minor amounts of other impuri­
ties. These by-products have to be eliminated because
they impair the use of hexetidine in pharmaceutical
compositions. Removing these by-products by distilla­
tion involves practical difficulties because the most
important ones have almost the same boiling point as
hexetidine. When separating hexetidine nicotinate in
2Q the form of a salt of low solubility from solutions of
hexetidine or acid addition salts thereof by adding nico­
tinic acid or a salt thereof, the undesired by-products,
which under these conditions form more readily solu­
ble salts, remain dissolved.
25 By adding hexetidine nicotinate to an aqueous solu­
tion of a base, hexetidine is set free and can be ex­
tracted into a water-immiscible organic solvent, the
solvent being finally removed from the extract.
The free hexetidine base is obtained by adding hexet-
30 idine nicotinate to solutions of, e.g. aliphatic or aro­
matic amines or alkaline earth hydroxides. Aqueous
buffer solutions having a higher basicity may also be
used. Preferred bases include 0.1-IN sodium hydrox­
ide, sodium carbonate, 0.1-IN potassium hydroxide
The chemical and physical data of this new com­
pound are as follows:
Elemental analysis: C.27H5oN402
Calculated:
Found:
C
70.08
69.31
H
11.15
10.78
N
12.10
11.92
O
6.92
7.87
Molecular weight: 462.73
IR spectrum: 3250 cm-1 (NH)
1630 cm-1 (amide I)
The process of this invention for preparing this new
compound relies on the fact that hexetidine nicotinate
separates from solutions of hexetidine or its acid addi­
tion salts when adding nicotinic acid or a salt thereof.
The process for preparing hexetidine nicotinate is
therefore characterized in that a solution of hexetidine
or an acid addition salt thereof in an organic solvent is
reacted with nicotinic acid or a salt thereof in a molar
and aqueous ammonia. The free hexetidine base is
extracted into a water-immiscible solvent. Preferred
extraction agents include petroleum ether (40°-80°C),
55 benzene and diethyl ether. In a special embodiment of
the invention the solvent is removed under vacuum
(5-10 mm Hg) at 40°-50°C, yielding hexetidine of
more than 99% purity.
Pure hexetidine obtained in this manner serves as an
60 excellent starting material for preparing the corre­
sponding nicotinic acid salt, especially when using the
latter as active compound in pharmaceutical composi­
tions.
Suitable solvents include normally-liquid (i.e. liquid
65 at room temperature), aliphatic, alicyclic and aromatic
hydrocarbons, lower aliphatic alcohols having up to 6
carbon atoms or mixtures thereof with water, ketones
having up to 6 carbon atoms, aliphatic and alicyclic
ethers having up to 8 carbon atoms, acid amides, and
sulfoxides. Preferred solvents include petroleum ether
3,946,013
3
(40°-80°C), methanol, n-hexane, dimethyl formamide,
isopropanol, benzene, and ethyl alcohol.
The reaction with nicotinic acid or a salt thereof is
conveniently carried out at a temperature below the
boiling point of the solvent, preferably at a temperature
of about 40° to 60°C.
The following examples serve to illustrate the inven­
tion, without being construed as limiting the scope of
protection.
EXAMPLE 1
Hexetidine (1 mole) was dissolved in 1,000 ml petro­
leum ether (40°-80°C) and nicotinic acid (1 mole) was
added dropwise under stirring at 25°C. The reaction
mixture was refluxed for 2 hours and cooled to room
temperature under stirring to give a crystal slurry which
was filtered under vacuum and dried at 50°-80°C.
Hexetidine nicotinate yield: 60 percent (m.p.
108°-llHoC).
EXAMPLE 2
Hexetidine (1 mole) was dissolved in 1,000 ml meth­
anol and heated to 50°C. To the solution nicotinic acid
(1 mole) was added dropwise. After stirring for 1.5
hours at 50°C, half of the solvent was distilled off under
vacuum at 40°C. The crystal slurry obtained at room
temperature was filtered and recrystallized from acetic
acid ethyl ester, yielding hexetidine nicotinate as white
crystals.
Yield: 70 percent.
EXAMPLE 3
Hexetidine (0.1 mole) was dissolved in 40.0 ml n-
hexane and heated to 55°C. Nicotinic acid (0.1 mole)
was added under stirring. Hexetidine nicotinate precip­
itated after cooling to room temperature.
Yield: 70 percent.
EXAMPLE 4
4
was then cooled to room temperature. Hexetidine nico­
tinate precipitated and was separated under vacuum.
Yield: 65-70 percent
5 EXAMPLE 8
A. To obtain the free base, hexetidine nicotinate
prepared from 1 mole crude hexetidine (80% purity)
was added to 1,000 ml IN sodium hydroxide solution.
After the addition of petroleum ether (40°-80°C), the
mixture was stirred until the salt was completely dis­
solved. The organic phase was separated, washed with
water and dried. The solvent was removed under vac­
uum (about 5-10 mm Hg) at 40°C.
15 Pure hexetidine yield: 50-60 percent.
B. To obtain the free base, hexetidine nicotinate
prepared from 1 mole crude hexetidine (80% purity)
was suspended in an excess of IN aqueous potassium
hydroxide solution, then 1,000 ml benzene were added.
2o After the salt was completely dissolved the organic
phase was separated, washed with water and dried over
sodium sulfate. The solvent was removed under vac­
uum (5-10 mm Hg) at 50°C.
Pure hexetidine yield: 60-70 percent.
25 C. Hexetidine nicotinate obtained from 1 mole crude
hexetidine (80% purity) was mixed with an excess of
3% ammonia solution. The free hexetidine base was
taken up in 50.0 ml diethyl ether. The organic phase
was separated, washed with water and dried over so-
30 dium sulfate. The solvent was removed under vacuum
(5-10 mm Hg) at 50°C.
Pure hexetidine yield: 70 percent.
D. Hexetidine nicotinate obtained from 1 mole crude
hexetidine (80% purity) was mixed with an excess of
35 IN sodium hydroxide solution and the free base was
taken up in 60.0 ml petroleum ether (40°-80°C). The
organic phase was dried over sodium sulfate and the
solvent was removed under vacuum (5-10 mm Hg) at
50°C.
Hexetidine (0.1 mole) was dissolved at 40°C in di­
methyl formamide, 0.1 mole nicotinic acid was added
and the solution was stirred for 0.5 hours at 40°C. After
cooling, hexetidine nicotinate precipitated and was
recovered.
Yield: 80 percent.
EXAMPLE 5
Hexetidine (0.1 mole) was dissolved in 30.0 ml iso­
propanol and heated to 60°C. After addition of 0.1
mole nicotinic acid, the solution was cooled to room
temperature under stirring and the resultant crystal
slurry of hexetidine nicotinate was filtered under vac­
uum.
Yield: 60-70 percent.
EXAMPLE 6
Hexetidine (0.1 mole) was dissolved in benzene at
40°C and nicotinic acid was added dropwise. The solu­
tion was reacted for 2 hours and cooled under stirring
to yield crystals of hexetidine nicotinate which were
filtered and dried.
Yield: 60 percent
EXAMPLE 7
Nicotinic acid (0.1 mole) was dissolved in 45.0 ml
ethanol and 0.1 mole hexetidine in 10.0 ml ethanol
were added dropwise under stirring at 50°C. Stirring
was continued at 50°C for 2.5 hours and the solution
40 Pure hexetidine yield: 80 percent.
E. Hexetidine nicotinate obtained from 1 mole crude
hexetidine (80% purity) was treated with an excess of
5% aqueous sodium carbonate solution and taken up in
45 petroleum ether (40°-80°C). The organic phase was
separated and dried. The solvent was removed under
vacuum (5-10 mm Hg) at 50°C.
Pure hexetidine yield: about 60 percent.
F. Hexetidine nicotinate obtained from 1 mole crude
5q hexetidine (80% purity) was mixed with IN potassium
hydroxide solution. After the addition of 40.0 ml di­
ethyl ether, the solution was stirred until the salt was
completely dissolved. The organic phase was dried over
sodium sulfate and the extracting agent removed under
55 vacuum (5-10 mm Hg) at 40°C.
Pure hexetidine yield: 60 percent.
G. Hexetidine nicotinate obtained from 1 mole crude
hexetidine (80% purity) was mixed with an excess of
3% ammonia solution. The free hexetidine was taken
60 up in 40.0 ml petroleum ether. The extracting agent
was removed under vacuum (5-10 mm Hg) at 40°C.
Pure hexetidine yield: 65 percent.
The purity of hexetidine obtained in (A) to (G) is
99.92 to 99.98 percent. Index of refraction of the pure
65 product: [n[02<*= 1.4652.
Reaction of pure hexetidine with nicotinic acid or a
salt thereof according to examples 1 to 7 gives the
desired hexetidine nicotinate in high yields.
3,946,013
5
TOXICITY AND BACTERIOSTATIC ACTIVITY
When subjecting hexetidine, hexetidine oxalate, hex-
etidine cinnamate and hexetidine nicotinate to toxico­
logical and microbiological comparative tests, hexeti­
dine nicotinate was found to have particularly favor­
able properties. Thus the toxicity of hexetidine was
substantially reduced by . the salt formation reaction
with nicotinic acid. Female NMRI mice having a body
weight of 20-30 g were used as test animals. The obser­
vation period was 10 days. The hexetidine salts were
suspended in commercial carboxymethyl cellulose and
10 ml/kg of the suspension were injected. The results
were determined by the method of Litchfield and Wil-
coxon (G. T. Litchfield and F. G-. Wilcoxon in Phar­
macol. exp. Therap. 96, 99 (1949)).
The following LD^ values were obtained:
Test Compound Toxicity, LD<50
Hexetidine
p.o.
(mg/kg)
960
(519 - 1,776)
i.p.
(mg/kg)
33
(20 - 55)
Hexetidine oxalate 970
(561 - 1,678)
23
(19 - 29)
Hexetidine cinnamate 1,740
(1,543 - 1,963)
54
(35 - 83)
Hexetidine nicotinate 1,830
(1,331 -2,516)
63
(46 - 86)
For a determination of bacteriostatic activity, solu­
tions of hexetidine, hexetidine oxalate and hexetidine
nicotinate having the following compositions were
compared:
Hexetidine solution 100 mg hexetidine per 100 ml
Hexetidine oxalate solution 113.2 mg hexetidine oxalate
(corresponding to 100 mg hexe­
tidine) per 100 ml
Hexetidine nicotinate 136.2 mg hexetidine nicotinate
solution (corresponding to 100 mg hexe­
tidine) per 100 ml
The inoculum suspension was obtained by inocula­
tion of a sterile Petri dish containing nutrient agar
(standard I) with a test culture of bacterial parent
strains (Escherichia coli, Proteus vulgaris, Pseudomo-
6
nas aeruginosa) and incubation at 30°C for 24 hours.
The suspension was either used immediately or stored
at +4°C. The organisms grown in the Petri dish were
elutriated with 5 ml physiological brine solution and
diluted 1:10 with the same solution to a volume of 50
ml. Then 250 ml double concentrated thioglycolate
solution (60 g/1) were mixed with 100 drops (about 5
ml) of the above 1:10 diluted primary culture of bacte­
rial parent strains and shaken to obtain a uniform sus­
pension. Serial dilutions were prepared for each of the
above-mentioned compound solutions in the following
concentrations, each comprising 10 test tubes of 100
ml:
hexetidine per ml: 1,000; 500; 250; 125; 62.5; about
31; about 16; about 8; about 4; about 2.
Next, 5 ml double concentrated thioglycolate nutri­
ent solution inoculated with the test organisms were
added to each test tube by means of a pipet. Each test
tube thus contained 50% of the final concentration.
The results were determined after incubation of the
serial dilutions at 30°C for 24 to 72 hours. Complete
absence of cloudiness (growth) in a test tube after 72
hours incubation indicates the minimum inhibitory
concentration (MIC).
The table shows the bacteriostatic activity in relation
to concentration:
Solution
Hexetidine con­
tained in 100 mg
solution
Bacteriostatic activity after
1 2 3 4 5 6 days
Hexetidine
Hexetidine
100 mg 125-y
oxalate
Hexetidine
100 mg 500-y
nicotinate 100 mg 62.5-y
All samples were incubated at 30°C for 6 days.
After 6 days hexetidine still showed a satisfactory
activity at a concentration of 125y. Hexetidine oxalate
showed no significant activity at a concentration of as
high as 500-y, whereas hexetidine cinnamate could not
be tested due to extreme insolubility. Hexetidine nico­
tinate still showed an activity at a concentration of
62.5-y.
What is claimed is:
1. 1,3-Bis (/3-ethylhexyl)-5-amino-5-methylhexahy-
dropyrimidinepyridine-3-carboxylate.
$
5
10
15
20
25
30
35
40
45
50
55
60
65