AU2018322279A1

AU2018322279A1 - Mouthwash containing octenidine hydrochloride

Info

Publication number: AU2018322279A1
Application number: AU2018322279A
Authority: AU
Inventors: Sabine Behrends; Andreas Dettmann; Thomas Spuida
Original assignee: Schuelke and Mayr GmbH
Current assignee: Schuelke and Mayr GmbH
Priority date: 2017-08-23
Filing date: 2018-08-10
Publication date: 2020-03-19
Also published as: SG11202001406WA; DE102017119261A1; EP3672569A1; WO2019038110A1

Abstract

The present invention relates to an aqueous composition which contains octenidine dihydrochloride. The composition is preferably used as mouthwash or oromucosal solution.

Description

Mouthwash Containing Octenidine Hydrochloride

The present invention relates to an aqueous composition which contains octenidine dihydrochloride. The composition is preferably used as a mouthwash or oromucosal solution (solution for use in the oral cavity) , for i) transient germ count reduction in the oral space, ii) inhibition of plaque formation iii) in case of limited oral hygiene capability.

DE 10 2006 051 891 Al discloses a water-based antimicrobially active composition which contains a bispyridinium alkane (such as octenidine dihydrochloride, also referred to below as octenidine) , and the use of the composition as a mouth rinse solution or oral antiseptic. Compositions given as examples have a pH of 4 and have good activity in the quantitative suspension experiment with E. faecalis (ATCC 19433) and in the quantitative suspension experiment with various MRSA isolates under dirty conditions. In addition, some formulations in DE 10 2006 051 891 Al contain phenoxyethanol. A disadvantage with phenoxyethanol is the furry taste.

For a pleasant taste, in DE 10 2006 051 891 Al it is for example proposed to use aspartame as a sweetener. If one now attempts, starting from this teaching, to further improve the taste or the compositions of DE 10 2006 051 891 Al, for example by increasing the quantity of flavouring used, the quantity of sweetener must also be increased, and, in order to increase the storage stability, also the quantity of emulsifier. However, it has been found than an increased quantity of emulsifier decreases the antimicrobial activity of compositions with a content of octenidine.

DE 10 2008 011 691 A discloses a stabilized antimicrobially active water-based composition which contains a bispyridinium alkane, and use of the composition for the production of

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PCT/EP2018/071817 microbicidally active cosmetic and pharmaceutical preparations and for the production of microbicidally equipped articles. As stabilizers, antioxidants, complexing agents, reducing agents, UV filters and light stabilizers are proposed. Application solutions described in DE 10 2008 011 691 A contain aspartame as sweetener and in the presence of DL-a-tocopherol are storage stable even on storage at 40°C over a period of six months (i.e. no formation of aldehydes or peroxides is observed).

DE 10 2005 045 146 A discloses antimicrobial compositions which contain octenidine encapsulated in liposomes. DE 196 47 692 A discloses a disinfecting composition which contains octenidine, Ci to Cg alkyl alcohol, nonionic and/or cationic surfactant and skin-compatible α-hydroxycarboxylic acid.

The present invention was based on the objective of providing aqueous compositions based on the active substance octenidine, which on the one hand are pleasant in taste (i.e. in which the bitter intrinsic taste of octenidine is not apparent), which however on the other hand contain as few as possible additives which are not necessary for the antimicrobial action and the taste. The compositions should nonetheless exhibit very good storage stability.

It has now surprisingly been found that this problem is solved by an aqueous composition which contains

a) 0.07 to 0.13 wt. % octenidine dihydrochloride,

b) 1.0 to 2.5 wt. % fatty acid monoglyceride substituted with 20 to 70 alkoxy groups,

c) 0.3 to 0.6 wt. % glycerine,

d) gluconic acid or gluconic acid salt, in a quantity of 0.2 to 0.6 wt.%, stated as sodium gluconate,

e) 0.03 to 0.2 wt.% sucralose,

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f) citric acid or 0.05 to 0.15 (anhydrous),

g) flavouring and

h) buffer.

citric acid salt, wt.-%, stated in a quantity of as citric acid

The composition according to the invention has a pH in the range from 5.0 to 7.0 and contains no aspartame. In addition, the aqueous composition according to the invention is a clear solution. This solution is characterized by good antimicrobial activity, good storage stability and a pleasant taste.

According to a first aspect, the invention thus relates to the aqueous composition. According to a second aspect, the invention relates to use of the aqueous composition as a mouthwash or oromucosal solution.

The aqueous composition according to the invention according to the first aspect contains

a) 0.07 to 0.13 wt. % octenidine dihydrochloride,

c) 0.3 to 0.6 wt. % glycerine,

e) 0.03 to 0.2 wt.% sucralose,

f) citric acid or citric acid salt, in a quantity of

0.05 to 0.15 wt.%, stated as citric acid (anhydrous),

g) flavouring and

h) buffer, wherein the composition

- has a pH in the range from 5.0 to 7.0 and contains no aspartame.

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The quantity of component a) is preferably 0.08 to 0.12 wt.%, more preferably 0.09 to 0.11 wt.%, in particular about 0.1 wt. % .

The quantity of component b) is preferably 1.5 to 2.0 wt.%, in particular about 1.75 wt.%.

The fatty acid monoglyceride substituted with 20 to 70 alkoxy groups is preferably fatty acid monoglyceride substituted with 20 to 70 ethoxy groups, in particular glycerol hydroxystearate substituted with 40 ethylene oxide units.

The quantity of component c) is preferably 0.35 to 0.5 wt.%, more preferably 0.4 to 0.45 wt.%, in particular about 0.425 wt. % .

The quantity of component d) is preferably 0.3 to 0.5 wt.%, more preferably 0.35 to 0.45 wt.%, in particular about 0.4 wt. % .

The quantity of component e) is preferably 0.05 to 0.15 wt.%, more preferably 0.07 to 0.13 wt.%, in particular about 0.1 wt. % .

The quantity of component f) is preferably 0.07 to 0.11 wt.%, 0.08 to 0.1 wt.%, in particular about 0.09 wt.%.

The quantity of component g) is preferably 0.1 to 1.0 wt.%, more preferably 0.2 to 0.8 wt.-%, in particular about 0.5 wt. % .

The flavouring g) is preferably selected from gl) a mixture of menthol with menthone, g2) strawberry flavouring, g3) banana flavouring and g4) cherry flavouring, or a mixture of two or more thereof.

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The buffer h) is preferably a phosphate buffer.

Preferably the composition contains less than 1 wt. % phenoxyethanol, more preferably less than 1 wt. % aromatic alcohol, in particular less than 0.5 wt. % aromatic alcohol, with the composition particularly preferably being free from aromatic alcohol.

More preferably the composition contains no tocopherol and no derivative thereof, wherein the composition in particular contains no tocopherol, no derivative thereof and no BHT (butylhydroxytoluene).

Preferably compositions according to the invention are free from alpha-tocopherol, BHT, tocopherol acetate, BHA (butylhydroxyanisole) , dodecyl gallate or ascorbic acid, and preferably contain none of these components.

The composition according to the invention is preferably used as a mouthwash or oromucosal solution for i) transient microbial count reduction in the oral space, ii) inhibition of plaque formation or iii) in case of limited oral hygiene capability.

The advantages of the present invention follow in particular from the following examples. Unless otherwise stated, percentage information relates to weight.

Examples

Example 1 - Unsatisfactory taste of compositions with a rather low content of aspartame

In a formulation based on octenidine, the quantities of flavouring and sweetener and the flavouring types should be matched. The components are stated in Table 1.

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Table 1. Formulations tested in example 1.

Laboratory number	A	B	c	D	E
Purified water	96.85	96.10	96.85	96.10	97.50
Octenidine	0.10	0.10	0.10	0.10	0.10
Glycerol 85%	0.50	0.50	0.50	0.50	0.50
Sodium gluconate	0.40	0.40	0.40	0.40	0.40
1.5% Cremophor RH 40 + 0.35% Flavour Mint Cool 79770-36	1.85
2% Cremophor RH 40 + 0.5% Flavour Mint Cool 79770-36		2.50
1.5% Cremophor RH 40 + 0.35% Flavour Mint Cream			1.85
2% Cremophor RH 40 + 0.5% Flavour Mint Cream				2.50
1% Cremophor RH 40 + 0.25% Flavour Mint Cream					1.25
Aspartame	0.20	0.30	0.20	0.30	0.15
Citric acid	0.10	0.10	0.10	0.10	0.10
All adjusted to pH 4.0	100.00	100.00	100.00	100.00	100.00

The formulations A to E were compared by taste (Table 2):

Table 2. Taste comparison of the formulations tested in example 1

A	acceptable, however B is better
B	acceptable as regards flavour and sweetness, nothing bitter, but also not convincing
C	similar to D, C is somewhat better
D	a little too strong
E	acceptable, but the creamy flavour is missing

The results show that with a moderate content of aspartame it is not possible to create a pleasant taste in octenidinecontaining compositions.

Example 2 - Storage stability of a formulation with aspartame

In the following experiments the storage stability of a formulation with aspartame was tested (Table 3).

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Table 3. Formulation tested in example 2

Water	97.60
Octenidine dihydrochloride	0.10
Glycerol 85%	0.50
Sodium gluconate	0.40
Cremophor RH 40	1.00
Flavour Mint Cool	0.25
Aspartame powder	0.15
Citric acid	to pH 4.0
	100.00

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Table 4. Storage stability of a formulation with aspartame.	u 0 O	1 month	almost clear, colourless	4.1	1.0027 \|	1.3364 \|	0.096 \|	0.115 \|	5/25°C same. 40°C flatter, less flavour	2 months	almost clear, colourless	4.0	1.0028 \|	1.3364 \|	0.095 \|	0.093* \|	1 1	Flatter, not so smooth, cool in mouth, still OK sweetness somewhat lacking.
u 0 in CXI	almost clear, colourless	4.1	1.0027	1.3364	0.098	0.143	almost clear, colourless	4.1	1.0027	1.3364	0.098	0.139*	1 1	Flavour + sweetness OK
Refrigerator (+3 to +8°C)	almost clear, colourless	4.1	1.0027	1.3364	0.098	0.151	almost clear, colourless	co	1.0027	1.3364	0.097	0.150	1 1
u 0 m 1	almost clear, colourless	4.1	1.0027	1.3364	0.099	0.152	opalescent, colourless	4.1	1.0027	1.3364	0.098	0.151	1_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________1	still OK, not so smooth
Null values	almost clear, colourless	4.1	1.0028	1.3364	0.099	0.153	almost clear, colourless	4.1	1.0028	1.3364	0.099	0.153	1 1
	Appearance	pH Cone.	Density, g/cm³	Refractive index	Octenidine, %	Aspartame in %	Taste	Appearance	pH Cone.	Density, g/cm³	Refractive index	Octenidine, %	Aspartame, %	NTU	Taste

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u 0 O

3 months

almost clear, yellowish

4.1

1.0027 |

1.3365 |

0.093* |

0.060* |

1 1

1___________________35___________________I

Sweetness and flavour lacking, disturbing offtaste. Somewhat bitter

6 months

almost clear, yellowish

0.091* |

0.030* |

1 1

1_____________________47_____________________I

unsatisfactory

9 months

almost clear, yellowish

* Oh co

u 0 in CM

almost clear, colourless

4.1

1.0027

1.3364

0.096

0.129*

1 1

similar to -5°C

almost clear, colourless

0.098*

0.110*

1 1

1_________________22_________________I

without comparison OK, not quite as at -5°C

almost clear, colourless

* kO Oh

Refrigerator (+3 to +8°C)

almost clear, colourless

4.0

1.0027

1.3364

0.097

0.148*

1____________ζ·ε____________I

1 1

almost clear, colourless

0.099

*8frl’O

1____________3’3____________I

1 1

almost clear, colourless

00 Oh

u 0 m 1

opalescent, colourless

4.1

1.0027

1.3364

0.098

*801’0

1_________1^8__________I

1 1

Balanced flavour and sweetness. Entirely OK, markedly better than 40°C

opalescent, colourless

0.100

0.146*

19.9

1 1

good

opalescent, colourless

00 Oh

Null values

almost clear, colourless

4.1

1.0028

1.3364

0.099

0.153

1 1

almost clear, colourless

0.099

0.153

1 1

almost clear, colourless

Oh Oh

Appearance

pH Cone.

Density, g/cm³

Refractive index

Octenidine, %

Aspartame, %

NTU

Hazen

Taste

Appearance

Octenidine, %

Aspartame, %

NTU

Hazen

Taste

Appearance

Octenidine, %

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υ 0 O

0.014* |

1 1

o

almost clear, yellowish

00 co

1.0033 |

1.3365 |

0.093* |

o.oi* |

1 1

u 0 in CM

* co ¢55

1 1

co

/3 5 £ tt ω ^ω · ° o c kJ >—1 ω ^m u

φ ^ωrH ^{Φ ϋ} ” Η |8 rd

ο

05 CXJ

CO co co

*

* 00

00 co

o

ω e in ο Ο -1—1 _ω LO iq -p ^4-)^4-)4-) , . Φ Φ C Φ ft rp φ P O tP Η Η ·η Ϊ C Φ Φ ,0 -H S 4q ^w Pi p υ U -Ho Φ Tt LO ^q i

Refrigerator (+3 to +8°C)

* 00 co

CXJ co

1 1

<0 £ +> G O

5 ω rd co ω ^υ Η ω ο |8 id

00 CXJ

co co co co

o

*

LO co

1 1

u 0 m 1

* CXJ

00 CXJ

1 1

ω o LO CN C Λ +J H Φ 4-) Φ Φ £ ω

E 04

J ^{ω υ} π ω C ο Φ Q a 8 ο ^υ

00 CXJ

co co co co

o

*

05 LO CXJ

1 1

Null values

co LO

1 1

5 ω rd co ω ^υ Η ω ο |8 id

00 CXJ

s co co

05 05

co LO

1 1

o\° Φ e +J ίλ ω C

L2 H Ϊ5

c Φ Nl rd

Φ 4-) Φ Φ H

φ υ C φ iq Φ Φ ίλ ίλ C

ίλ

e υ -Ρ Η ω C φ Q

X Φ Ό C Η Φ Η 4-) O Φ iq Ψ4 Φ it

o\° Φ •H T5 •H Φ -P υ o

o\° Φ e φ 4-) iq ίλ ω C

L2 H Ϊ5

c Φ Nl rd

Φ 4-) ω Φ H

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υ 0 O	18 months	almost clear, yellowish	00 CO	1.0038 \|	1.3370 \|	0.098* \|	<0.01 \|	1 1	σδ
u 0 in CM	ο ^ωrH ^Φ »1 ίϋ	σδ co	co	LO CO co co	* 00 σδ	co	σδ co	CXJ	o c Φ Φ r—\| +4 44 Ώ ω φ Φ Φ tP 4-) +4 C ίλ Ο Φ > .H U τφ O P o e
Refrigerator (+3 to +8°C)	5 ω rd co ω ^υ X ω ο \|8 rd	ο	00 CXJ	co co co co	* 00 σδ	co	co	1 1
u 0 m 1	_ρ ^ω 5 ^υ π ο id ο a 8 ο ^υ	ο	00 CXJ	co co co co	* 00 σδ	co	σδ CXJ	1 1
Null values	5 ω rd co ω ^υ X ω ο \|8 rd		00 CXJ	s co co	Οδ σδ	co LO	1 1	1 1	Ό Φ 44 4-) 44 Φ C Φ Λ Φ Φ s s a i φ a c n a ω ω 2 φ λ; ο φ
	φ υ C φ χ φ φ ίλ ίλ C	ίλ	e υ -P -H ω C Φ Q	X Φ Ό C -H Φ -H +J U Φ X 4-1 Φ it	ο\° φ μ Η τ5 Η £ Φ -μ υ ο	o\° Φ e φ 4-) 44 Φ ίλ Φ c	H	μ Φ 1X1 rd	(ύ —ι β Φ ο φ ^υ > 5 Η C ·Η Φ Φ Ό C Ν ·Η Ο Φ X) Η X 4-) X Η \|\| 4-) Ό Ό C II Φ Φ Ν ^3 II Φ Η ______* Μ 2

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The data confirm the unsatisfactory storage stability of octenidine-containing formulations with the sweetener aspartame, even when formulated at the pH of about 4 recommended for aspartame for optimal stability.

Example 3 - Storage stability of a formulation without aspartame

In the following experiments, a formulation with 0.2% octenidine and with a high content of nonionic surfactant was tested so as to be able to better simulate the decomposition.

In Tables 5 and 6, the contents of octenidine and two known decomposition products (keto compound and imino compound) are stated. The aqueous formulations A to M were tested, each with 0.2% octenidine dihydrochloride and addition of 0.1% citric acid monohydrate, and 1) emulsifier (macrogol glycerol hydroxystearate-4OEO) and 2) the stated agents for adjustment of the pH (NaOH = 5% aqueous sodium hydroxide, phosphate = Na₂HPO₄*2H₂O) .

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Table 5. Stability test 3 months, unopened bottles 250 ml (Mo = month(s))

pH	3.9	3.8	3.8	6.1	5.9	00 LG	6.1	6.0	5.9	4.8	4.3	4.1	4.9	4.9	4.9	5.0	5.0	4.9	4.0	4.0	4.0	3.8	3.6	3.4
Keto compound in ppm	LG V	LG V	LG V	LG V	LG V	LG V	LG V	LG V	LG V	LG V	LG V	LG V	LG V	LG V	< 5	LG V	< 5	LG V	LG V	LG V	LG V	LG V	LG V	00
Imino compound in ppm	o	09		σΊ	09	V¹		09	09	<-1	09		V¹	o	09	09	<-1	09	09	09		09	V¹	09
Octenidine in %	0.210	0.214	0.215	0.211	0.214	0.217	0.210	0.213	0.215	0.215	0.218	0.219	0.209	0.214	0.216	0.207	0.212	0.215	0.208	0.211	0.213	0.210	0.211	0.214
	Null values	3 Mo 40°C	3 Mo 50°C	Null values	3 Mo 40°C	3 Mo 50°C	Null values	3 Mo 40°C	3 Mo 50°C	Null values	3 Mo 40°C	3 Mo 50°C	Null values	3 Mo 40°C	3 Mo 50°C	Null values	3 Mo 40°C	3 Mo 50°C	Null values	3 Mo 40°C	3 Mo 50°C	Null values	3 Mo 40°C	3 Mo +50°C
	1.75% emulsifier, pH 4.0	1.75% emulsifier, pH 6.0 NaOH	1.75% emulsifier, pH 6.0, phosphate	1.75% emulsifier, pH 5.0	1.75% emulsifier, pH 5.0, NaOH	1.75% emulsifier, pH 5.0, phosphate	1.75% emulsifier, pH 4.0, phosphate	5% emulsifier, pH 4.0. unbuffered
Batch	c	m	ω	Q	ω		u

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pH	6.0	00 LG	5.7	4.9	4.4	4.0	4.9	4.9	4.8	5.0	4.9	8 · fr	4.1	4.0	4.0
Keto compound in ppm	LG V	LG V	LG V	LG V	LG V	00	LG V	< 5	< 5	LG V	LG V	LG V	LG V	LG V
Imino compound in ppm	<-1	00	09	09	09	09 09	09	09		V¹	<-1	00	09	V¹	09 09
Octenidine in %	0.212	0.215	0.214	0.209	0.212	0.212	0.214	0.216	0.219	0.210	0.212	0.214	0.214	0.214	0.216
	Null values	3 Mo 40°C	3 Mo 50°C	Null values	3 Mo 40°C	3 Mo 50°C	Null values	3 Mo 40°C	3 Mo 50°C	Null values	3 Mo 40°C	3 Mo 50°C	Null values	3 Mo 40°C	3 Mo 50°C
	5% emulsifier, pH 6.0, phosphate	5% emulsifier, pH 5.0, unbuffered	5% emulsifier, pH 5.0, NaOH	5% emulsifier, pH 5.0, phosphate	5% emulsifier, pH 4.0, phosphate
Batch	1—1		id

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Table 6. Stability test 6 months, bottles opened once, 250 ml

pH

3.9

3.8

3.6

6.1

00 LG

5.7

6.1

6.0

00 LG

4.8

4.2

3.7

4.9

4.8

5.0

4.9

4.0

3.8

3.5

3.2

ε

&

a

d

τ)

β

LO

LG

00

&

V

ε

0

ο

0

-Ρ

φ

ε

&

a

d

τ)

a

Ρ

ο

,—1

00

σΊ

,—1

00

Ά0

CN

09

,—1

09

LG

«ςφ

CD

09

CN

CD

09

,—1

CN

CD

LG

&

1—1

ι—Ι

1—1

i—l

1—1

i—l

CN

i—l

CN

i—l

CN

LG

ε

0

ο

0

a

d

ε

Η

dP

a

d

φ

ο

^-1

00

09

o

Ά0

,—|

LG

σΊ

09

σΊ

ID-

CN

ID-

Ά0

o

00

LG

σΊ

o

Ά0

LG

a

,—|

CN

,—|

CN

,—|

CN

,—|

CN

CD

,—|

CN

CD

,—|

CN

CD

,—|

d

CN

τ)

d

CD

a

φ

-Ρ

ο

.ues

ω 0

.ues

ω 0

.ues

ω 0

.ues

ω 0

.ues

ω 0

.ues

ω 0

.ues

ω 0

.ues

ω 0

(ϋ >

+

LG +

(ϋ >

+

LG +

(ϋ >

+

LG +

(ϋ >

+

LG +

(ϋ >

+

LG +

(ϋ >

+

LG +

(ϋ >

+

LG +

(ϋ >

+

LG +

ο

o

S

2

Ά0

2

Ά0

2

Ά0

2

Ά0

2

Ά0

2

Ά0

λ

ο

-Ρ

C

m

ω

Q

ω

u

φ

PQ

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pH

6.0

00 LG

5.4

4.9

4.2

3.4

4.9

4.8

4.7

5.0

4.9

4.7

4.1

4.0

3.9

ε

&

c

d

τ)

β

LO

LG

Ρ

00

υ &

V

ε

0

ο

0

-Ρ

φ

ε

&

α

Η

τ)

α

Ρ

[—

LG

,—1

09

[—

00

09

σΊ

«ςφ

09

[—

&

τ—1

00

τ—1

CN

τ—1

09

ε

0

ο

0

α

Η

ε

Η

<λ°

α

Η

φ

CN

00

^-|

σΊ

LG

«ςφ

ο

«ςφ

ο

«ςφ

σΊ

^-|

α

τ—|

J—|

CN

J—|

τ—|

09

J—|

τ—|

CN

τ—|

J—|

CN

Η

CN

09

CN

τ)

Η

C3)

α

φ

-Ρ

ο

.ues

ω 0

.ues

ω 0

.ues

ω 0

.ues

ω 0

.ues

ω 0

(ϋ >

+

LG +

(ϋ >

+

LG +

(ϋ >

+

LG +

(ϋ >

+

LG +

(ϋ >

+

LG +

ο

S

2

λ

ο

-Ρ

|—|

•“0

iU

φ

PQ

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Example 4

Formulations I to VII and IX to XI

The purpose of this formula validation was to find out what effect the concentration of the emulsifier (Cremophor RH 40) and a change in the pH have on the product stability and on its antimicrobial activity.

The emulsifier content was studied around the actual value of 1.75% in a bandwidth from 1.0% to 2.0%. These experiments took place at the average octenidine dihydrochloride concentration (0.15%) .

The pH was studied around the currently envisaged shelf life specification from 5.5 to 6.3 at the low limit of 5.4 and the upper limit of 6.4. In this, the highest octenidine dihydrochloride concentration (0.2%) was tested at both pH extremes, but on the other hand the lowest octenidine dihydrochloride concentration (0.1%) only at the lower pH limit (Table 7) .

Table 7

	0.10% Octenidine	0.15% Octenidine	0.20% Octenidine	Test to be performed
Effect of pH (shelf life specification 5.5-6.3) pH 5.4 and pH 6.4	6.4	—	5.4 + 6.4	Stability test with pH measurement, in vitro activity testing
Effect of emulsifier (Cremophor RH 40) 1.0%, 1.25%, 1.4%, 1.6%, 1.75%, 1.9%, 2.0%	—	X	—	Stability test with physical data, appearance in refrigerator, in vitro activity testing

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The following materials were used (Table 8):

Table 8

Name	Content
Glycerol 85%	0.5%
Sodium gluconate	0.4%
Sucralose	0.1%
Butylhydroxytoluene (BHT)	0.005%
Flavour Mint Cool PHL 132974	0.5%
Citric acid monohydrate	0.1%

The following compositions were formulated (Table 9):

Table 9

	I	II	III	IV	V	VI	VII
Cremophor RH 4 0, %	1.0	1.25	1.4	1.6	1.9	2.0	1.75
Octenidine, in %	0.15	0.15	0.15	0.15	0.15	0.15	0.15
Sodium monohydrogen phosphate dihydrate	To pH 6.0	To pH 6.0	To pH 6.0	To pH 6.0	To pH 6.0	To pH 6.0	To pH 6.0
	IX	X	XI
Octenidine, %	0.10	0.20	0.20
Sodium monohydrogen phosphate dihydrate	To pH 6.4	To pH 5.4	To pH 6.4

For the formulations I to VII, in the context of a stability test, physical and chemical data were determined, and a study of the antimicrobial activity and an optical assessment of the refrigerator samples performed.

For the stability testing, under the conditions +25°C and + 40°C (not ICH conditions), the bottles (250 ml, PET) were stored as follows:

+25°C (ca. 35% RH), +40°C (ca. 12% RH), and in the refrigerator:

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PCT/EP2018/071817 ca. +3°C to +8°C (no temperature recording, only visual inspection).

After 4 weeks, the following parameters were studied for all samples. The visual assessment of the samples which were stored in the refrigerator in each case took place after 1, 2, 3, 4, 7, 10, 17, 24 and 28 days.

For the formulations IX, X and XI (test samples for effect of pH) , the stability of the pH was studied and additionally for the formulae X and XI the antimicrobial activity during storage .

For the stability testing under the conditions +25°C and +40°C in the stability rooms of F+E (not ICH conditions), the bottles (250 ml, PET) were stored as follows:

+25°C (ca. 35% RH), +40°C (ca. 12% RH), and in the refrigerator:

ca. +3°C to +8°C (no temperature recording) .

After 6 weeks the pH of all samples was studied (Table 10).

Table 10.

Test parameter	Method
Appearance	visual
PH cone.	Ph .Eur. 2.2.3
Density in g/cm³	Ph .Eur. 2.2.5
Refractive index	Ph .Eur. 2.2.6
Octenidine dihydrochloride content in %	LC 144 ¹
Imino compound in ppm	LC 123 ¹
Keto compound in ppm	LC 123 ¹
Butylhydroxytoluene content in ppm	LC 145 ¹

¹ = Method not validated, presumable LOD for degradation products: 4 ppm

3.1 Effect of emulsifier content, formulations I to VII:

a) Physical and chemical data (at start and after 4 weeks storage):

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Tabl

Keto compound, ppm

< 4

_

< 4

_

< 4

_

< 4

_

< 4

1_________________________________________________________________________________________________________________________________________________1

Imino compound, ppm

00

ν’

LQ

kO

LQ

kO

ν’

LQ

kO

ν’

LQ

kO

BHT content, ppm

LQ

oo

kO

LQ

OO

LQ

kO

LQ

kO

LQ

Octenidine content, %

σι

00

CN LQ

σι

LQ

CN LQ

σι

CN LQ

LQ

OO

σι

LQ LQ

LQ

pH Cone .

kO

σι LQ

kO

LQ LQ

kO

Refractive index

1.3368

1.3367

1.3368

1.3372

1.3374

1.3373

1.3374

1.3377

1.3381

1.3380

Density, g/cm³

1.0042

1.0043

1.0042

1.0043

1.0045

1.0046

OO

1.0051

Null values

ω o OO 1 co

ω o LQ CN

ω o

Null values

ω o OO 1 co

ω o LQ CN

ω o

Null values

ω o OO 1 co

ω o LQ CN

ω o

Null values

ω o OO 1 co

ω o LQ CN

ω o

Null values

ω o OO 1 co

1—1

1—1 1—1

1—1 1—1 1—1

ί—1

>

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1_______L>_______1	_	< 4		_	_	_	< 4		_	_	1_________________________________________________________________________________________________________________________________________________1
1________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________1	LQ	LQ			LQ	LQ	LQ		00		LQ
1_____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________\		CO			LQ	LQ	CN LQ		00	00	OO
\ 0.157	0.157	0.149		0.149	0.149	0.150	0.145		0.145	0.145	0.144
0'9	LQ Oh LQ
1.3381	1.3381	1.3382		1.3382	1.3383	1.3383	1.3379		1.3379	1.3379	1.3379
1.0051	1.0051	1.0052		1.0052	1.0052	1.0052	1.0050		1.0050	1.0050	1.0050
	ω o	Null values		ω o 00 1 00	ω o LQ CN	ω o	Null values		ω o 00 1 00	ω o LQ CN	ω o
			F					F F

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b) Optical assessment (over 28 days storage), Table 12 (n.c. = no change) (Day 1) :_________________________________________________

	25°C	40°C	3-8°C
I	n.c.	n.c.	n.c.
II
III
IV
V
VI
VII

(Day 2):

	25°C	40°C	3-8°C
I	n.c.	n.c.	very many crystals
II	rather more crystals than in III
III	first small crystals
IV	n.c.
V	n.c.
VI	n.c.
VII	n.c.

(Day 3):

	25°C	40°C	3-8°C
I	n.c.	n.c.	very many crystals
III			isolated crystals
IV	n.c.
V	n.c.
VI	n.c.
VII	n.c.

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PCT/EP2018/071817 (Day 4):

	25°C	40°C	3-8°C
I	n . c .	n . c .	very many crystals
II	a few large crystals
III	isolated crystals
IV	n . c .
V	n . c .
VI	n . c .
VII	n . c .

(Day 7):

(Day 10):

	25°C	40°C	3-8°C
I	n . c .	n . c .	very many crystals
II	very many crystals
III	many crystals
IV	n . c .
V	n . c .
VI	n . c .
VII	n . c .

(Day 17):

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PCT/EP2018/071817 (Day 24):

(Day 28):

Assessment of the physical and chemical and optical data for I to VII:

After 4 weeks storage with all formulations no significant changes in the physical and chemical properties are seen.

In the optical examination, in the samples which were stored 10 at +25°C and +40°C, no visible abnormalities were found after 6 weeks storage.

On the other hand, in the samples which had been stored in the refrigerator, it is found that an emulsifier content of 15 at least 1.6% (formulation IV) is advantageous for adequate solubilization to ensure stability as regards precipitates / crystallization effects. All formulations with lower additions of emulsifier already show signs of precipitates after short-term cold storage of only 2 days.

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Based on the above precipitation findings, it follows that the minimum emulsifier content to ensure the physical stability of the product solution is 1.6%, on the basis of which, with a safety increment of rel. 10%, the current emulsifier actual content of 1.75% is to be regarded as appropriate .

c) Results of the studies on the antimicrobial activity in vitro :

In order to investigate a possible effect of the emulsifier content (Cremophor RH 40) on the antimicrobial activity, quantitative suspension experiments according to EN 13727 (Staphylococcus aureus ATCC 6538 and Pseudomonas aeruginosa ATCC 15442) and EN 13624 (Candida albicans ATCC 10231) were each performed on the formulation with average active substance concentration (0.15%).

The following values were determined for

Candida albicans (Table 12):

Table 12

	Emulsifier content	Exposure time 30 seconds	Exposure time 60 seconds
I	1.0%	>4.38	>4.38
II	1.25%	>4.38	>4.38
III	1.4%	3.76	>4.38
IV	1.6%	3.65	>4.38
V	1.9%	2.42	3.51
VI	2.0%	1.38	2.78
VII	1.75%	2.22	3.97

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The following values were determined for Staphylococcus aureus (Table 13) :

Table 13

	Emulsifier content	Exposure time 30 seconds	Exposure time 60 seconds
I	1.0%	>5.64	>5.64
II	1.25%	3.92	>5.64
III	1.4%	4.31	>5.64
IV	1.6%	>5.64	>5.64
V	1.9%	4.05	>5.64
VI	2.0%	3.46	4.80
VII	1.75%	>5.64	>5.64

The following values were determined for Pseudomonas aeruginosa (Table 14) :

Table 14

	Emulsifier content	Exposure time 30 seconds	Exposure time 60 seconds
I	1.0%	>5.27	>5.27
II	1.25%	>5.27	>5.27
III	1.4%	4.29	5.14
IV	1.6%	4.25	>5.27
V	1.9%	4.04	>5.27
VI	2.0%	3.24	>5.27
VII	1.75%	4.53	5.27

Assessment of the antimicrobial activity of Formulae I to VII From the above results it is clear that higher emulsifier concentrations cause a reduction in the in vitro antimicrobial activity, particularly pronounced at the highest tested used concentration of 2.0%, at shorter exposure times.

In comparison to the formulae with lower emulsifier content, the in vitro antimicrobial activity of the currently intended formulation using 1.75% emulsifier seems to be slightly reduced sometimes, but overall is to be regarded as adequate.

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Based on indications of a significantly worse antimicrobial performance of the formulation with addition of 2.0% emulsifier, an increase in the addition of emulsifier above the 1.75% necessary for physical stabilization cannot be justified.

Example 3.2 Effect of the pH, formulations IX-XI

a) pH stability (initially and after 6 weeks storage)

Table 15

	pH
	IX	X	XI
Null values	6.4	5.4	6.4
25°C	6.3	5.4	6.4
40°C	6.3	5.4	6.3
3-8°C	6.3	5.4	6.4

Assessment of the pH stability

After 6 weeks storage at the storage temperatures +25 and + 40°C and in the refrigerator at +3 to +8°C, no significant changes in the pH are seen.

b) Results in the studies of antimicrobial activity in vi tro

In order to investigate a possible effect of the pH on the antimicrobial activity, quantitative suspension experiments according to EN 13727 (Staphylococcus aureus and Pseudomonas aeruginosa) and EN 13624 (Candida albicans) were each performed with the preparations mentioned below.

The following values were determined for Candida albicans (Table 16):

Table 16

Lab. No.	Oct. cone .	pH	Exposure time 30 seconds	Exposure time 60 seconds
II	0.2%	5.4	>4.38	>4.38
III	0.2%	6.4	3.76	>4.38

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The following values were determined for Staphylococcus aureus (Table 17) :

Table 17

Lab. No.	Oct. cone .	pH	Exposure time 30 seconds	Exposure time 60 seconds
II	0.2%	5.4	5.05	>5.64
III	0.2%	6.4	>5.64	>5.64

The following values were determined for Pseudomonas aeruginosa (Table 18) :

Table 18

Lab. No.	Oct. cone .	pH	Exposure time 30 seconds	Exposure time 60 seconds
II	0.2%	5.4	>5.27	>5.27
III	0.2%	6.4	5.16	>5.27

Assessment of the antimicrobial activity depending on the pH From the above results it can be clearly seen that the 0.2% formulations at the pH specification limits of pH 5.4 and pH 6.4 show no significant differences in the in vitro antimicrobial activity. On this basis, the desired tolerance range from pH 5.5 - 6.3 for the shelf life specification can be regarded as confirmed.

Example 3.3 Overall assessment and conclusion

The results of this formulation study confirm that the emulsifier content of 1.75% is necessary to ensure the physical stability of the solution with regard to precipitates and crystallization effects; because of an adverse effect of increasing emulsifier concentration on the in vitro antimicrobial activity, a further increase in the quantity added is not justifiable.

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Over the confirmed storage time of 4 weeks, the other physical and chemical properties under all storage conditions (refrigerator, 25°C and 40°C) do not show a different shelf5 life behaviour depending on emulsifier quantity added.

Within the desired tolerance range from pH 5.5 - 6.3, a significant effect of the pH on the antimicrobial activity of the desired formulation can be ruled out on the basis of the 10 in vitro activity measurements. In addition, the studies confirm the stability of the pH values at the lower and upper limit of the tolerance range on 6 weeks storage under all confirmed storage conditions (refrigerator, 25°C and 40°C).

Claims

Claims

1. Aqueous composition which contains

a) 0.07 to 0.13 wt. % octenidine dihydrochloride,

b) 1.0 to 2.5 wt. % fatty acid monoglyceride substituted with 20 to 70 alkoxy groups,

c) 0.3 to 0.6 wt. % glycerine,

d) gluconic acid or gluconic acid salt, in a quantity of 0.2 to 0.6 wt.%, stated as sodium gluconate,

e) 0.03 to 0.2 wt.% sucralose,

f) citric acid or citric acid salt, in a quantity of 0.05 to 0.15 wt.%, stated as citric acid (anhydrous),

g) flavouring and

h) buffer, wherein the solution

- has a pH in the range from 5.0 to 7.0 and

- contains no aspartame.
2. Composition according to Claim 1, characterized in that the quantity of component a) is 0.08 to 0.12 wt.%, preferably 0.09 to 0.11 wt.%, in particular about 0.1 wt.%.
3. Composition according to Claim 1 or 2, characterized in that the quantity of component b) is 1.5 to 2.0 wt.%, in particular about 1.75 wt.%.
4. Composition according to one of the previous Claims, characterized in that the fatty acid monoglyceride substituted with 20 to 70 alkoxy groups is fatty acid monoglyceride substituted with 20 to 70 ethoxy groups, in particular glycerol hydroxystearate substituted with 40 ethylene oxide units.

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5. Composition according to one of the previous Claims, characterized in that the quantity of component c) is 0.35 to 0.5 wt.%, preferably 0.4 to 0.45 wt.%, in particular about 0.425 wt.%.
6. Composition according to one of the previous Claims, characterized in that the quantity of component d) is 0.3 to 0.5 wt.%, preferably 0.35 to 0.45 wt.%, in particular about 0.4 wt.%.
7. Composition according to one of the previous Claims, characterized in that the quantity of component e) is 0.05 to 0.15 wt.%, preferably 0.07 to 0.13 wt.%, in particular about 0.1 wt.%.
8. Composition according to one of the previous Claims, characterized in that the quantity of component f) is 0.07 to 0.11 wt.%, preferably 0.08 to 0.1 wt.%, in particular about 0.09 wt.%.
9. Composition according to one of the previous Claims, characterized in that the quantity of component g) is 0.1 to 1.0 wt.%, preferably 0.2 to 0.8 wt.%, in particular about 0.5 wt.%.
10. Composition according to one of the previous Claims, characterized in that the buffer is a phosphate buffer.
11. Composition according to one of the previous Claims, characterized in that it contains less than 1 wt.% phenoxyethanol, preferably less than 1 wt.% aromatic alcohol, in particular less than 0.5 wt.% aromatic alcohol, wherein the composition especially preferably is free from aromatic alcohol.

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12. Composition according to one of the previous Claims, characterized in that it contains no tocopherol and no derivative thereof, wherein the composition contains no tocopherol, no derivative thereof and no BHT.
13. Use of the composition according to one of the previous claims as mouthwash or oromucosal solution.
14. Use of the composition according to Claim 13, for i)

10 transient microbial count reduction in the oral cavity, ii) inhibition of plaque formation or iii) in case of limited oral hygiene capability.