NL8900076A - COMPOSITION FOR ORAL HYGIENE. - Google Patents

Description

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Oral hygiene formulation.

The invention relates to compositions for oral hygiene and to methods of using these compositions for preventing or inhibiting the growth of bacteria on dental surfaces.

Preventing the adhesive deposit of dental plaque on teeth of mammals (especially humans) is highly desirable. Dental plaque width when cariogenic and other types of bacteria build up in colonies on the surface of teeth and form a deposit, which adheres firmly to the surface. Deposition of plaque on the surface of a tooth is believed to be one of the first steps in the development of dental caries and periodontal disease.

Many attempts have been made to prevent plaque deposition on dental surfaces and to prevent plaque removal from these surfaces. Brushing, toothpicks and the use of oral irrigators and interdental stimulators have been attempted. However, these treatments are not completely successful and often need to be supplemented by periodic treatments by dental professionals.

European patent 0,182,523A, recently published in applicant's teachings, teaches that certain pharmaceutical compositions (as defined therein) are very effective in preventing or greatly reducing (a) colonizing dental surfaces or simulated dental surfaces by cariogenic and other microorganisms. , which are usually found in an oral environment and (b) the adhesive deposition on dental surfaces of plaque due to these microorganisms.

The preparation of polymers for use in the aforementioned pharmaceutical compositions is described in EP 30 0.182.523A, the contents of which are to be considered as incorporated herein.

Chlorhexidine is a cationic antiseptic, which has been widely used for over 20 years by the medical profession as a topically applied antibacterial agent; Their preparation is described in British Patent Specification UK 705,838. It is stated (Löe et al., Journal of Periodontal Research, 1970, Vol 5, pp. 79-83), that chlorhexidine can be used as an antiseptic in the oral environment and that in certain cases- 8900076 c "1 * 4 - 2 - Len chlorhexidine apparently tends to discolor teeth, such discoloration appears to be a property common to cationic antiseptics (Addy et al., Journal of Periodontal Research, volume 9, pp. 134-140). such discoloration results from an interaction between the cationic antiseptic and food ingredients, especially those rich in tannins, for example, coffee, tea or red wine.

It has now been found that when certain surfaces, for example teeth or hydroxyapatite, are treated with a combination of both (a) a polymer, as defined below, that has certain pendant polyalkylene oxide chains as (b) a cationic antibacterial agent, the resulting treated dental surfaces surprisingly have both stronger anti-adhesive and antibacterial properties for certain microorganisms, ie the combination can provide control of so-called "biological contamination" of dental surfaces.

Indeed, in the presence of the polymer, equivalent antibacterial effects can be observed when the tooth surface is treated with a lower concentration of a solution of the antibacterial agent. Furthermore, it was surprisingly found, (1) that the aforementioned tendency for discoloration with chlorhexidine is at least reduced, often there is no increase in discoloration, even when more chlorhexidine is adsorbed on the tooth surface in the presence of the polymer, (2) antibacterial properties of certain cationic antibacterial agents, eg chlorhexidine and alexidine, are enhanced on simulated tooth surfaces when the surface is successively treated with or with a combination of an acidic polymer, eg Polymer 93W (as defined below) and the aforementioned agent ; and (3) where restorations, for example, Occlusion (RTM), Opalux, Silux and Valux P50, etc. are discolored by cationic antiseptics, this discoloration is at least reduced in the presence of the polymer. It will be understood that reducing discoloration of at least the front teeth is particularly desirable.

The invention provides an oral hygiene composition containing (1) an effective amount of a cationic antibacterial agent; and 8900076. " - 3 - * (2) an effective amount of at least one polymer, as defined below, which has one or more pendant polyalkylene oxide groups.

As examples of cationic antibacterial agents which can be used in the present invention, mention may be made, inter alia, of benzalkonium chloride, bispyridine amines, eg octenidine, and preferably a poly biguanide, eg alexidine, and most preferably a bis biguanide, eg chlorhexidine.

By "polybiguanide" is meant a compound having in the chain a number of biguanide residues of the formula 1 of the formula sheet or tautomers thereof. Often there are two, three or four such in-chain residues in the antibacterial agent used in the present invention. However, the possibility is not ruled out that there are sufficient to provide at least a majority of the repeat units of a higher molecular polymer, for example, with a molecular weight of up to about 10,000.

It will be understood that when a polybiguanide 20 is used in the present invention, it may be present as a free base; however, it is preferably present as a salt thereof, for example acetate or hydrochloride, and most preferably, especially when the polybiguanide is a bis-biguanide having the structure shown under 2 on the formula sheet as the di-gluconate, i.e. say the di-gluconate of 1,6-di (4-chlorophenyl-di-guanido) hexane, which is known in the art as chlorhexidine.

The possibility is not excluded that when a polybiguanide, for example chlorhexidine, is used in the present invention in the form of a free base, it may be present on the tooth surface, mixed (eg as a salt) with an acidic polymer, as defined below.

As possible explanations of the great antibacterial effect of the oral hygiene composition according to the invention are suggested; (1) an increase in the amount of chlorhexidine adsorbed on the tooth surface; and / or (2) change in the strength of adsorption of chlorine-the hexidine dental surface such that it is more available to exert the antibacterial effect at the surface; egg / or Ö300076? k - 4 - (3) change in the orientation at the tooth surface of adsorbed chlorhexidine, such that its antibacterial groups are more accessible to the bacteria moving thereon; and / or 5 (4) ion pairing between the cationic antibacterial agent and the acid anions, if any, of the polymer.

In the composition of the invention, multiple hydrogen bonds between the polymer and the biguanide cations can contribute to the aforementioned increase in amount or change in strength of adsorption or orientation.

Polymers that are present in the oral hygiene composition of the invention are preferably acid, which is understood to include at least one carboxylic acid group attached to that polymer hull. However, the possibility is not excluded that the polymer is amphoteric, basic or neutral, although this is not preferred.

The one or more pendant polyalkylene oxide groups adhered to the polymers and present in the oral hygiene compositions of the invention are preferably ethyleneoxy-20 groups. However, the possibility cannot be excluded that at least a part thereof are alternative poly (lower) alkylene oxide groups, for example polypropylene.

As examples of polymers present in the oral hygiene composition according to the invention, mention may be made of polymers containing one or more repeat units with the general structure A shown in the formula sheet under 3 and one or more repeat units with the general structure B shown on the formula sheet under 4, wherein X, which may be the same or different in the repeat units of the structure A and Y, which may be the same or different in the repeat units of the structure B, are hydrocarbyl or substituted hydroxycarbyl residues, which provide a polymer shell; 1 2

Z is -CHR -CHR - or - (CH) -; where, when Z

1 2 2 m 35 -CHR -CHR - is, R, which may be the same or different in the same repeat unit of the structure B (when n or q is 2 or more) or in the different repeat units of the structure B, hydrogen qo ^ r hydrocarbyl group; and 2 - 5 - *

R, which is in the same repetition unit with the structure B.

(when n and q is 2 or more) or may be the same or different in different repeat units of structure B, hydrogen or a hydrocarbyl group; with the proviso that in R 2 and R 1 a single unit -CHR -CHR -O- cannot be both hydrocarbyl; 3 R, which may be the same or different in the same repeat unit of structure B (when q is 2 or more) or in the different repeat units of structure B, is hydrogen or a hydrocarbyl group or an acyl group derived from an alkanoic acid with up to five carbon atoms; m, if present, is a number from 2 to 10; n is a number from 1 to 60; p is a number from 1 to 4; and 15 q is a number from 1 to 4; each (CO 2 H) group is linked via an intermediate or intermediates L to the hydrocarbyl residue X, and in the cases where p is 2 to 4, it can be joined by L with the same or different carbon atoms of X; L can be the same or different in the repeat units of structure A and is selected from one or more direct bonds and one or more groups of atoms, each group providing a chain of one or more atoms to bond a (CO H) group with X, except that more than two (CO 2 H) groups cannot be directly bonded to the same carbon atom in X; 3 each ((ZO) R) group is bonded to the hydrocarbyl residue Y through an intermediate or intermediate M, and in cases where q is 2 to 4, it may be joined by M with the same or different carbon atoms of Y; 30 M in the repeat units of the structure B may be the same or different and is selected from one or more direct bonds and one or more groups or atoms, each group providing a chain of one or more atoms for bonding a (so) group with n Y, with the proviso that more than two (zo) groups cannot be directly bonded to the same carbon atom in Y; the ratio of the number of -CO ^ H groups and the number of (SO) groups, especially when Z is -CH CH -, is in the range of from 1:20 to 20: 1.

12

Preferably, both R and R, when present 8900076 <* t Η - 6 -, are hydrogen.

1 2

When R or R is a hydrocarbyl group, it is preferably a lower alkyl group, most preferably methyl.

3 R is preferably a lower alkyl group, most preferably methyl.

When Z is - (CH 2) m is preferably 4; this provides 2 m for an easy preparation of - (ZO) from tetrahydrofuran.

It is to be noted that the definition of the polymer in the composition (as given above) is also intended to include a polymer in which at least some of the carboxyl groups in the repeating units of the general structure A have been converted to the corresponding salt anions CO ^ - (which are considered as -CO ^ H group as far as the ratio of carboxyl and -ZO groups is concerned), the corresponding cations being, for example, those of ammonium (NH ^ +) or alkaline earth metals and preferably alkali metals (e.g. 15 example - Na +, K). The possibility is not excluded that the cation may be derived from the cationic antibacterial agent per se; since the cationic antibacterial agent is present as a salt of the acidic polymer, such that there is virtually no free chlorhexidine in the mouth, there is a tendency to further reduce discoloration.

In the general structure A, each carboxyl group is joined to the hydrocarbyl residue X by means of an intermediate or intermediates (ie by a linking unit or units) designated by L which is selected from one or more direct compounds (i.e. one or more direct bonds) and one or more groups of atoms, each group providing a chain of one or more atoms to bind a carboxyl group or groups with X. In cases where p is 2 to 4, each carboxyl group is attached by L to the same or, in cases where R represents more than one intermediate, to the same or different carbon atoms in X, although of course more than 2 carboxyl groups may not be directly bound to the same carbon of X (and also assuming, that in such cases X contains at least 2 carbon atoms, while it will be understood that it is within the scope of the invention that X contains only 1 carbon atom). It should be noted that in principle R can represent 4 to 4 separate intermediates in structure A (in cases where p is 4). L may be the same or different in the repeat units of structure A.

8900076? - 7 -

In cases where L represents one or more groups of atoms, each group providing a bonding chain of atoms, the chain will normally contain one or more carbon atoms (which may include, for example, carbon atoms in an aryl ring) and / or hetero-5 atoms (in especially N and / or O). Examples of possible bonds provided by L are shown on the formula sheet under A, wherein (apart from the direct compound) the top compound is at X and the bottom compound or compounds are at carboxyl. However, it is preferred in the present invention that L be one or more direct compounds such that each carboxyl group is directly associated with a carbon atom in the polymer hull.

In the structure A, p is preferably 1 or 2, most preferably 1 (so that L can represent one or at most two intermediates).

3

In structure B, each (ZO) ^ R group is joined to the hydrocar-15-byl residue Y by an intermediate or intermediates (i.e., by a linking unit or units), which are designated by M, which is selected from one or more direct compounds (i.e., one or more direct bonds) and one or more groups of atoms, each group providing a chain of one or 3 more atoms for joining a (ZO) ^ R group or groups with Y In cases where q is 2 to 4, each (ZO) ^ R ^ through M may be united with the same or, in cases where M represents more than one intermediate, the same or different carbon atoms in Y, although more then two (SO) R groups cannot of course be directly connected to the same carbon of Y (and further assuming that in such cases Y contains at least 2 carbon atoms, while it will be understood that it is within the scope of the invention, that Y contains only 1 carbon atom). M may be the same or different in the repeat units of the structure B.

Although M may represent one or more direct bonds, it is preferred in the present invention that M be one or more groups of atoms, each group providing a linking chain of atoms; such a Chain will normally contain one or more carbon atoms (which may include, for example, carbon atoms in an aryl ring, e.g., benzyl ether) and / or heteroatoms (especially N and / or O). Particularly preferred examples of chains provided by M are those of the formula 5a and 5b of the formula sheet wherein the top compound is Y and the bo-8900076.

- 8 - dem connection is on (Z0) n R ^.

In the structure B, q is preferably 1 or 2, most preferably 1 (so that M can then represent one or at most two intermediates).

Preferably, structure A represents the repeat unit, which can be obtained by the addition polymerization (usually initiated by free radicals) of a polymerizable olefinically unsaturated carboxylic acid. Examples of such acids are maleic or fumaric acid, itaconic acid, the acids of formulas 6a and 6b of the formula sheet (N-methacryloylalanine and N-acryloyl-10-hydroxyglycine, respectively) and preferably acrylic acid or methacrylic acid.

Preferably, structure B represents the repeat unit obtained by the polymerization (usually free-radical initiated) of an addition polymerizable olefinically unsaturated ester or amine prepared by the reaction of an unsaturated carboxylic acid (or an esterifiable or amidizable derivative thereof, such as an acid chloride or anhydride) and a hydroxyl compound of the formula HO (ZO) R (to form the ester) or an n 3 amine of the formula H_N (ZO) R (to form the amide).

2 n

Preferably, the acid from which structure B can be derived is acrylic acid or methacrylic acid, especially the last, whereby when an ester or amide derivative of methacrylic acid is used, the structures of formulas 7a and 7b, respectively, are B are obtained.

Preferably, acidic polymers present in oral hygiene compositions of the invention have a ratio of acid residues and pendant polyalkylene oxide residues of about 6: 1 (when each side chain is polyethylene glycol having a molecular weight of about 350, i.e., so-called PEG 350) .

Polymers for use in the present invention are described in detail in applicant's European Patent Specification 0,182,523A, the contents of which are to be considered herein.

In oral hygiene compositions of the invention, the at least one polymer contained therein is typically present in at least a concentration of about 0.05 to 30% by weight of the composition, and the preferred concentration ranges from about 0.1 to 5% by weight .% and most preferably from 0.2 to 2% by weight.

The concentration of the at least one antibacterial agent in oral hygiene compositions according to the invention is about 8900070 * - - 9 - 0.001 to 10% by weight of the composition and the preferred concentration range is from about 0.001 to 1.0% by weight and most preferably from 0.01 to 0.1% by weight.

Preferably, the mass of the polymer is greater than the mass of the antibacterial agent in oral hygiene compositions of the invention. However, the possibility is not excluded that more antibacterial agent than polymer is present.

The oral hygiene composition of the invention typically contains only one polymer as defined above, although it is not excluded that two or more such polymers may be present in the composition.

The person skilled in the art can formulate compositions according to the invention by simple tests in which the ratio of antibacterial agent and polymer is such that undesired reaction is avoided.

The oral hygiene composition of the invention typically contains a pharmaceutically acceptable carrier, which is compatible with the antibacterial activity of the cationic antibacterial agent, for example chlorhexidine. In order to maintain the activity of chlorhexidine, it may be necessary to adjust its concentration in a particular carrier and a suitable concentration may be determined experimentally by the skilled person.

Suitable conventional pharmaceutically acceptable carriers which can be used in the oral hygiene compositions of the invention include water, ethanol (in which water or a water / ethanol mixture is often a major component of the carrier); moisture containers such as propylene glycol, isopropanol, glycerol and sorbitol; gelling agents such as cellulose derivatives, for example hydroxypropyl and hydroxyethyl cellulose, polyoxypropylene / polyoxyetherheir block copolymers (so-called "Poloxamers"), for example Synperonic PE 39/70 and PEF 87; certain gel stabilizers such as polyvinylpyrrolidone; sweeteners such as sodium saccharin; preservatives such as cetylpyridinium chloride and certain lower alkyl parahydroxy benzoates; surfactants such as polyoxyethylene isohexadecyl ether 35 (Arlasolve 200) and certain colorants and flavors, from the approved EEC and PD and C lists. It will be understood that the aforementioned carrier is selected so as not to inhibit the effectiveness of the oral hygiene composition of the invention too much; in particular an anionic material, for example an anionic cellulose derivative or an anionic Synperonic, is not preferred.

The oral hygiene compositions of the invention may be in the form of any conventional pharmaceutically acceptable oral hygiene formulation containing an effective amount (and compatible with) a polymer and antibacterial agent as defined above. As examples of such formulations can be mentioned among others mouthwashes, rinses, irrigating solutions, abrasive and abrasive-containing gel toothpastes, dental cleaners, coated dental floss, coated or impregnated tooth bristles (natural or synthetic), interdental stimulator coatings, calgon , tablets, breath fresheners, foams and sprays.

The invention is now illustrated in the following examples. The offset "CT" at an example number indicates a comparative test.

In most of the following examples, the oral bacteria Streptococus mutans NCTC 10449 was used as the standard bacteria. It was grown in Brain Heart Infusion (BHI) (ex 20 Oxoid) in a Bioflo Model C30 Fermenter. A 750 ml crucible containing 350 ml bacterial suspension was used. The bacteria were cultured at 37 ° C at a dilution rate of 0.1 h, an air flow of 0.24 liters / minute and a stirring speed of 300 revolutions per minute. A sample (about 20 ml) of bacterial suspension was taken from the fermenter for each experiment. The bacteria were centrifuged at 4000 rpm for 10 minutes, resuspended in modified Ringer's saline solution (0.54 gram / liter NaCl; 0.02 gram / liter KCl; 0.03 gram / liter CaCl 3; and 0.75 gram / liter sodium capaptoacetate), centrifuged, resuspended and diluted 30 (10x) in modified Ringer's saline solutions. The bacterial concentration in the diluted saline solutions was about 10 ml Streptococcus mitior NCTC 7864 was grown in 100 ml Brain Heat Infusion culture liquid in batch culture for 24 hours. The culture was then centrifuged at 3500 rpm for 30 minutes. and washed twice by resuspending the pellet in saline and centrifuging The bacterial suspension was then adjusted to about 10 -10 cells per ml.

89 0 0076 / - 11 -

Complete saliva was used in the following examples.

Absorption surfaces

Hydroxyapatite disks were prepared by compressing hydroxyapatite powder (tribasic calcium phosphate (Ca ^ (0H) 2 (PO ^) ^ 5 (ex Aldrich)) and sintering at 1100 ° C. The disks were reused after heating in an oven at 900 ° C C for 2 hours between experiments.

Application of the polymers

Hydroxyapatite disks were treated with a solution (1 w / v) of a polymer, for example, Polymer 93W, in a 1: 1 (volume) mixture of industrially methylated spirit / water for 2 minutes at room temperature. The disks were then washed 5 times by dipping and shaking in a pot of running water at about 15 ° C.

15 Application of the antibacterial agent

Aqueous solutions of chlorhexidine and IMS solutions of alexidine were adsorbed separately for certain periods on the surfaces of hydroxyapatite disks, which, when appropriate, were treated with polymer (untreated disks were used in the comparative tests). The disks were then washed by dipping 5 times and shaking in a pot of running water.

Polymers

The polymer, referred to herein as "Polymer 93W", is an acidic polymer as described and prepared in Example 5 of applicants EP 182523. (Other "acidic" polymers described below are prepared by the same method). Polymer 93W contains methacrylic acid and PEG 350 MAt residues in a molar ratio of 6: 1.

By "PEG 350 MAt" is meant a polyethylene oxide 50 having a molecular weight of about 350, which is protected by methoxy and methacryloyl groups, ie CH = C (CH_) COO (CH „CH„ 0) CH „, where n is about 8 is.

2 o 2 2 n - PEG 150 Mat, PEG 1000 Mat and PEG 2000 Mat are similar polyethylene oxides with molecular weights of 150, 1000 and 2000, respectively.

Polymer Mil was prepared under the conditions described in Example 15 of EP 182,523, except that a PEG with hydroxy end groups was used instead of a PEG with amino-89 0 007 6? Λ - 12 - end groups.

Loeffler's Methylene Blue 95% Ethyl Alcohol (30 ml), methylene blue (0.3 g) and water (100 ml).

5 Examples 1-2

These examples demonstrate that Polymer 93W retains the anti-adhesive properties in the presence of absorbed chlorhexidine.

Hydroxyapatite disks were treated with a 1 w / w% solution of Polymer 93W and then with certain antibacterial agents for certain periods of time. The disks thus treated were immersed in a bacterial suspension (30 ml) in a petri dish for 2 hours. The disks were removed from the bacterial suspension and washed by dipping and shaking in a vessel with running water for 5 times. Bacteria adhering to the disks were stained using Loeffler's Methylene Blue. The reduction in bacterial adhesion was determined by microscopic examination.

The results are shown in Table 1.

Table 1 20 Example Antibacterial Agent Polymer% Anti-Adhesion CT1 O 1% 93 W 99 1 C 1% 93 W 99 2 A 1% 93 W 99 CTl: 1% of 93W Only Was Used 25 C: 1% Chlorhexidine A: 1% alexidine

Table 1 shows that chlorhexidine and alexidine do not reduce the anti-adhesion properties of Polymer 93W deposited on hydroxapatite 30 discs.

"% Anti-Adhesion" ("% AA") is defined by the equation: / area of | - [Surface of polymer-coated clean area / area covered with bact. /% AA - __r 1 ~ - -, ___ ί 35 / Surface of clean areas covered with bacteria / 89 0007 6 - 13 -

It will be understood that (a) when the polymer does not reduce the surface area of the area covered with bacteria,

% AA = X ^ X x 100 = 0 X

5 and (b) when the polymer prevents bacteria from adhering to the surface,

% AA = XHD x 100 = 100 X

The same results were obtained when a sample of material normally used in the preparation of a dental prosthetic member, as described below, was treated with polymer 93W and chlorhexidine and then exposed to Streptococcus mitior NCTC 7864.

Examples 3-5

These examples demonstrate that on hydroxyapatite the antibacterial effect of chlorhexidine is enhanced at certain concentrations when used in the presence of Polymer 93W.

Chlorhexidine solutions were absorbed onto sterile hydroxyapatite disks treated with Polymer 20 93W. Cells of S. mutans were taken from the fermenter and diluted 100-fold in BHI agar at 40 ° C. The inoculated agar was placed on HAP discs.

Agar-coated discs were incubated at 37 ° C overnight. Bacterial growth through the agar was rated on a scale of 0 (no growth) to 10 (control).

Since the surface of each hydroxyapatite disc was contacted with the same number of bacteria in all cases, the anti-adhesion did not contribute to the result found, i.e. the antibacterial effect was measured alone. The results in Table 2 show that the combination of Polymer 93W and chlorhexidine gave an increased antibacterial effect compared to chlorhexidine per se at the same concentration of chlorhexidine used.

In the comparative tests CT's 2, 3, 4 and 5, the 35 disks were not treated with Polymer 93W. Comparative Test 2 is a blank; in comparative test 2A, the disc was treated with only Polymer 93W.

0900076:

Y.

- 14 - Table 2

Example Applied chlorhexi- Treatment with Bacterial _dine concentration_Polymer 93W_growth_ CT2 0 not 10 5 CT2A 0 yes 10 CT3 1 no 8 CT4 0.1 no 10 CT5 0.01 no 10 3 1 yes 0 10 4 0.1 yes 2 5 0.01 yes 4

Examples 6-9

These examples demonstrate the combination of anti-adhesion and antibacterial results, which can be obtained by using a combination of a polymer and chlorhexidine, and that such combination gives an improvement over the individual components per se.

Sterile hydroxyapatite disks were treated at 1 w / v. solution of Polymer 93W and then with solutions 20 with certain concentrations of chlorhexidine. The disks were incubated for 1 hour at 37 ° C in freshly collected whole saliva and washed by dipping and shaking 5 times in a vessel of running water. Excess water was removed from the surface of each disc by touching its edge with filter paper.

BHI agar containing 0.04 w / v. Bromo Cresol Green (to visualize bacterial growth on the white hydroxyapatite disks) was pipetted onto the disks at 40 ° C to form a thin film of agar on the surface.

The disks were incubated at 37 ° C overnight. 30 The results are shown in Table 3.

In comparative tests 6-10, treatment with Polymer 93W was omitted. In Comparative Test 11, Polymer 93W was used in the absence of chlorhexidine.

d90007fir - 15 -

Table 3

Example Concentration of Presence of Bacterial Chlorhexidine (%) Polymer 93W_growth_ CT6 1 no growth 56 1 no growth CT7 0.1 non control level 4.

7 0.1 no growth CT8 0.01 no control 10 level 5.

8 0.01 a few colonies; more than 99% reduction compared to control level 5.

CT9 0.001 not control level 6.

20 9 0.001 99% reduction compared to control level 6.

25 CT10 0 not thick growth: control level 7.

CT11 0 as much as 90% reduction in CT730 control level 7.

Table 3 shows that at certain concentrations of chlorhexidine, for example 0.01 and 0.001%, the presence of Polymer 93W increases its bacterial and / or bacterial static effect. CT11 demonstrates the reduction in bacterial growth due to the anti-adhesion properties of the polymer per se.

Examples 10-20

These examples show that treating hydroxy-40 apatite discs with certain polymers (a) increases the amount of chlorhexidine absorbed thereon and 8900076. (b) improves the retention of the absorbed chlorhexidine in subsequent washes.

- 16 -

Preparation of Polymers B3 and B18

Methacryloyl chloride (0.58 moles) was added over 2 hours to a mixture of toluene (600 ml), Jeff "360" or "2070" (0.5 moles) and 2,6-lutidine (0.56 moles), chilled in an ice bath. A thick white precipitate formed. The reaction mixture was allowed to stand for 3 hours and the white precipitate was filtered off and washed with toluene. The filtrate was evaporated under reduced pressure and the residue was kept under vacuum to remove volatiles. The products (yield 80-90%) were characterized by infrared and proton magnetic resonance spectroscopy.

The amino-terminated products of both reactions (with butoxy or methoxy-terminated groups of "360" and "2070", respectively) were separately converted to their N-methacrylaloyl derivatives and copolymerized with methacrylic acid at the conditions described in Example 11 of EP 0.182.523A .

Hydroxyapatite disks were pre-equilibrated in double distilled water for 1 hour. The disks were removed from the water, blown dry and kept at room temperature for about 30 minutes. A UV reflection scan thereof was performed. The optical density at 266 nm was typically about 0.9. Any disc that has an O.D. which was significantly different from this number was discarded.

The acceptable disks were dipped in 1 w / w% (1: 1 / IMS: water) polymer solution for 5 minutes. The disks were removed from the polymer solution; they were washed 5 times by dipping and shaking in a pot of running water; they were blown dry, left to stand for 30 minutes and then scanned. Each of the polymer-coated disks was dipped in an aqueous (15 ml) chlorhexidine solution (0.02 w / v%) for 1 hour. They were washed as described above, left to stand for 30 minutes and then scanned. They were then placed in a flow-through (250 ml / min.) Wash tank (1200 ml) for 1 hour; blow dry; they were left for 30 minutes and scanned.

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Polymer A B Molar ratios nature of hull side chain A: B CHR ^ CHR ^ O:

(source) Mol.gew. CO ^ H

____; ____________ groups_ 5 73 basic (DMAEM) PEG 350 3: 1 BI2 amphoteric PEG 350 1.9: 1.1: 1 (MAA: DMAEM) 62 acid (MAA) PEG 150 3: 1 1: 1 86 acid (MAA) PEG 350 3.5: 1 2.3: 1 10 93W Acid (MAA) PEG 350 6: 1 1.3: 1 66 Acid (MAA) PEG 1000 3: 1 7.7: 1 B9 Acid (MAA) PEG 1000 25: 1 0.9: 1 58 Acid (MAA) PEG 2000 10: 1 4.5: 1 B3 Acid (MAA) Jeff 360 6: 1 1.1: 1 15 B10 Acid (MAA) Allyl- PEG 350 6: 1 1.3: 1 B18 Acid (MAA) Jeff2070 34: 1 1.2: 1 BI7 Acid (MAA) PPG 1000 17: 1 1: 1

Mild acid (MAA) PEG 350 5: 1 0.9: 1 DMAEM: N N-dimethyl-2-aminoethyl methacrylate.

MAA: Methacrylic acid.

MA: Maleic acid; PEG: Polyethylene glycol.

PPG: Polypropylene glycol; Jeff 360: n-C.H (OCH CH) OCH CH (CH) OCH CH (CH) NH; 4 y Z Z Q Z Z> Z 6 z

Jeff 2070: CH „0CHoCH„ 0 (CH „CHO) CH CH (CH) NH 3 2 2 2 | n 2 3 2

R

wherein n is such that "2070" has a molecular weight of about 2000 and R = H or CH 2 in a ratio of about 7: 3; Allyl PEG 350; ethoxylated allyl alcohol;

Except for B10, the methacrylate or methacrylamide derivatives of the listed side chains were present as general structure B; B10: contains terminal hydroxyl groups.

The aforementioned UV scanning was performed using a Unican SP1750 ultraviolet spectrophotometer.

The "difference in optical density" results reported in Table 4 were determined therefrom.

89 00 0 76 - 19 -

Tables 4 and 5 show that the acidic polymers significantly increase the amount of chlorhexidine absorbed. Many of the hydroxyapatite surfaces, coated with an acidic polymer, absorbed more chlorhexidine from 0.02 w / v. solution 5 then the clean hydroxyapatite surface from a 2 w / v. solution of chlorhexidine, that is, a more than 100 fold improvement was observed. The basic (Polymer 73) and amphoteric (Polymer Bl2) polymers did not improve the amount of chlorhexidine absorbed. Also polymethacrylic acid did not improve absorbed chlorhexidine, indicating that it was the PEG (or PPG) chains and not the carboxyl groups responsible for the observed effect.

The results of the wash tests showed that after 1 hour about 23% of the originally adsorbed chlorhexidine was still adsorbed on the bare hydroxyapatite disks, while the amount for polymer treated disks was about 80%. After washing overnight, the amount of chlorhexidine adsorbed, so much, that the residue on the clean HAP disks was below the detection limit; and about 50-60% of the amount of chlorhexidine originally adsorbed on polymer treated disks remained adsorbed. Thus, polymer treated disks absorbed more chlorhexidine than bare disks, and it was also less easy to wash off their surface.

Examples 21-29 25

These examples, in combination with Examples 10-20 and 6-9, show an increase in antibacterial properties (at a given chlorhexidine concentration), without the expected increase in discoloration.

General Method 30 Hydroxyapatite disks were pre-equilibrated in double-distilled water for 1 hour. The pre-equilibrated discs were immersed in 1 w / v% aqueous or IMS: water (1: 1) polymer solution for 5 minutes. They were removed from the polymer solution and washed by dipping and shaking 5 times in a vessel with running water. The 35 washed discs were then immersed in 15 ml of an aqueous chlorhexidine solution (at a concentration listed in Table 6) for 5 minutes. The discs were removed from the chlorhexidine solution and immersed for 1 hour at room temperature in 15 ml of a tea 890007 $ 20 solution. The discs were taken from the tea solution and washed as described above. -The steps of dipping in chlorhexidine and tea solution and washing were repeated 3 times using fresh chlorhexidine and tea solutions each time. After these three cycles, the disks were immersed in tea solution overnight; they were then washed as described above, allowed to dry at room temperature for 1 hour and the amount of discoloration formed thereon was evaluated.

The tea solution was prepared by adding 500 ml of boiling water to 2 tea bags. The teabags were removed after 5 minutes and allowed to cool to room temperature. The tea was filtered with a standard filter paper and stored at 4 ° C for use.

The discolored discs prepared in the general method were scanned using UV / visible reflectance spectrophotometry, as described in Examples 10-20, and compared with tea blanks (ie, no adsorbed chlorhexidine). Figure 1 shows typical UV traces obtained. In Figure 1, a = bare hydroxyapatite disc; b = tea blank; and c, d, e = tea / chlorhexidin-20 treatments at concentrations of 0.002, 0.02 and 0.2% chlorhexidine, respectively.

The polymers listed in Table 6 (the chemical composition of which is given in Table 5) were evaluated for their effect on the coloration of chlorhexidine in the presence of tea. The polymers were adsorbed separately from 1 w / v% IMS / water (1: 1) solutions. 0.2, 0.2 and 0.002 w / v% aqueous solutions of chlorhexidine were used. The disks were scanned using UV / visible reflectance spectrophotometry and the ODs at 266, 410 and 510 nm were measured. The ODs of tea blanks were also measured at these wavelengths, and these values were subtracted from discs treated with chlorhexidine or polymer / chlorhexidine combinations. Table 6 lists the results at 510 nm. They are expressed as discoloration ratios obtained with a tea blank = 1.0. Similar results were obtained at 266 nm and 410 nm. In CT 18, the polymer was omitted, i.e., chlorhexidine was used on its own.

8900076f - 21 -

Table 6

Comparative color development compared to "natural" build-up when exposed to tea solutions.

Example Polymer O.D. ratio (compared to natural tea color) at 510 nm at chlorhexidine concentrations of _0.2% _0.02% _0.002% CT18 - 4.57 2.76 1.67 21 73 4.48 3.01 1.0 10 22 62 4.98 2.65 1.0 23 86 4.48 3.26 1.0 24 93W 4.98 2.79 1.0 25 B9 4.75 3.09 <1.0 26 B3 4.39 3.34 1.0 15 27 B10 4.76 3.34 <1.0 28 B18 4.20 3.12 <1.0 29 B17 5.03 2.95 <1.0

Table 6 shows that at the two higher chlorhexidine concentrations (ie, 0.2 and 0.02%), the presence or nature of the polymer does not have a substantial effect on the amount of stains formed when treating HAP disks. At the lowest concentration (ie 0.002%) of chlorhexidine used, the majority of the examples show a significant reduction in discoloration equal to or less than the minimum levels upon exposure of HAP disks to the tea solutions. However, it would be apparent from the results of Examples 10-20 and 6-9 that, at about the same coloration as the control, the polymers had more chlorhexidine absorbed thereon and exhibit a greater antibacterial effect.

30 Examples 30-31

These examples illustrate the increase in the amount of chlorhexidine adsorbed on a hydroxyapatite disc treated with a mixture of chlorhexidine and Polymer 93W compared to treating the HAP disc with a chlorhexidine solution per se.

An IMS solution (2 w / v%) Polymer 93W was mixed with an appropriate (0.04 w / v%) solution of chlorhexidine in 890007%.

• V

- 22 - water with a solution volume ratio of 1: 1. Hydroxyapatite discs were left in the mixture for 1 hour and then washed five times with water. The amount of chlorhexidine absorbed on the disks was determined by UV reflectance spectrophotometry, as described in Examples 10-20 (the optical density was measured at 266 nanometers).

in comparative tests 20 and 21, the disks were treated for 1 hour with 0.2 and 0.02% solutions of chlorhexidine in a 1: 1 volume mixture of industrial methylated spirits and water, respectively.

The results are reported in Table 7. Table 7 shows that treating a HAP with the Polymer 93W / chlorhexidine mixture results in more chlorhexidine absorbed than from a chlorhexidine solution per se.

15 Table 7

Example Condition of Concentration Increase in the addition of chloro-optic dense composition hexidinity at w / v% 266 nm mixture 30 0.44 20 31 mixture 0.02 0.12 CT19 pure chlorhexidine solution 0.2 0.0 CT20 pure chlorhexidine solution 0.02 0.0 25 Examples 32-33

These examples illustrate the increased "kill" of a Polymer 93W / chlorhexidine mixture compared to pure chlorohexidine solution.

The disks produced in Examples 30-31 were washed overnight in water and subjected to an S. mutans agar ringing experiment. They were placed in a petri dish and covered with BHI agar (25 ml) S.mutans (100 µl), grown in a fermenter (as described above) and x 100 diluted Ringer's saline, pipetted on the agar and evenly distributed. The bacteria were grown overnight at 37 ° C; Bacteria "fields" and "clear zones" free of bacteria were noted and measured. The results are reported in Table 8. The clear zones, i.e. the zones where no growth occurred, are reported as a 89GGG7 £ - 23 percent of the area of the disk.

Table 8

Example Disc Manufacturing Concentration of% Surface area of the disc in Chlorhexidine disc where no 5% w / v growth occurred. 32 30 0.2 225 33 31 0.02 64 CT21 CT19 0.2 3 CT22 CT20 0. 02 0 10 It should be noted that where "percentage area of the disk where no growth occurred" is more than 100, this indicates that the inhibition had spread in the agar layer beyond the periphery of the disk.

Table 8 shows that the mixture had greater antibacterial activity compared to chlorhexidine per se.

Examples 34-65

These examples show that the combination of an anti-stick compound, Polymer 93W, and chlorhexidine reduces the amount of discoloration, compared to chlorhexidine per se, on a variety of surfaces found in the oral environment. The surfaces include teeth, composite restorative materials, for example Occlusin and Opalux, and a methacrylate-based resin, which is normally used in the manufacture of dental prosthetic devices (hereinafter referred to as "PR" for convenience).

25 Specimen

Residual meat was removed from freshly drawn teeth with a scalpel, the teeth were tumbled for 20 minutes in 50% sodium hypochlorite solutions and washed superficially with distilled water.

These and teeth containing restoration material were sonicated for 10 minutes in alcohol and then dried.

Samples of DR (25 x 10 x 3 mm) and discs of the aforementioned composite restoration materials were washed in alcohol and dried.

Solutions a) 1% and 0.5% solutions of Polymer 93W (1 g) in a mixture of industrial methylated spirits (50 ml) and water (50 ml).

890007 $? * - 24 - b) Solutions (0.2%, 0.02% and 0.002%) of chlorhexidine in water.

c) Appropriate mixtures of Polymer 93W and chlorhexidine were obtained by mixing equal volumes of solutions 5 of a) and b) to obtain the concentrations mentioned in the tables.

H

ties.

d) Human saliva was obtained by taking samples (20 ml) from each of 6 volunteers, centrifuging at 25,000 rpm for 20 minutes and pooling.

E) A tea solution was prepared by boiling a sample (8 g) of a commercial tea brand in distilled water (80 ml) for 2 minutes, cooling the product to room temperature and filtering off the remaining tea leaves.

Evaluation 15 Each surface was treated with a sample of the saliva for 10 minutes. The excess saliva was washed off.

In Examples 34-49, the sample was subjected to a first treatment for 10 minutes, superficially washed with distilled water, subjected to the second treatment for 10 minutes, rinsed and then immersed in the tea solution for 1 hour; the procedure was repeated, the sample was left in the tea solution overnight and the whole procedure was repeated every day for 5 days.

In Examples 50-65, the above-described 5-day procedure was repeated, except that the first treatment was carried out for 5 minutes and the second treatment was omitted, the samples were treated with the appropriate mixtures of Polymer 93W and chlorhexidine.

The discoloration of the surfaces was visually compared to the same surface, which had only been treated with water and rated on the following scale.

Scale 0: No discoloration (ie the water control was rated with 0, although there was minor discoloration); 35 1: Slight discoloration; 2; More moderate discoloration; 3: Heavy discoloration; and 4: Very heavy discoloration.

In tables 9, 10 and 17 0900071 "- 25 - OC = occlusin OP = Opalux T = tooth PR = Prosthesis resin

5 A = 0.5% Polymer 93W

AA = 1% Polymer 93W B = Water X = 0.1% Chlorhexidine XX = 0.2 Chlorhexidine 10 Y = 0.01 Chlorhexidine YY = 0.02 Chlorhexidine Z = 0.001 Chlorhexidine ZZ = 0.002 Chlorhexidine W = 0.0001 Chlorhexidine 15 Table 9

Example Surface Treatments Evaluation

First or Second only (10 min.) _ (10 min.) _ CT23 OC B 0 20 CT24 OP B 0 CT25 TB 0 CT26 PR 0 CT27 OC X 3 CT28 OP X 3 25 CT29 TX 3 CT30 PR X 3 CT31 OC AA 0 CT32 OP AA 0 CT33 T AA 0 30 Ct34 PR AA 0 34 OC AA XX 3 35 OC AA YY 1 36 OC AA ZZ 0 CT35 OC B XX 3 35 CT36 OC B YY 2 CT37 OC B ZZ 1 8900076 / - 26 -

Table 9 - continued

Example Surface Treatments Evaluation

First or Second only (10 min.) 5 _ (10 min.) _.__ 37 UP AA XX 4 38 UP AA YY 2 39 UP AA ZZ 0 CT38 UP B XX 3 10 CT39 UP B YY 2 CT40 UP B ZZ 1 40 T AA XX 4 41 T AA YY 2 42 T AA ZZ 0 15 CT41 TB XX 3 CT42 TB YY 2 CT43 TB ZZ 1 43 PR AA XX 4 44 PR AA YY 2 20 45 PR AA ZZ 0 CT44 PR B XX 3 CT45 PR B YY 2 CT46 PR B ZZ 1 46 OC XX AA 0 25 47 OP XX AA 0 48 T XX AA 0 49 PR XX AA 0 £ 900076: 1 - 27 -

Table 10

Example Surface Treatment Rating _ (mixture for 5 min.) _ CT47 OC B 0 5 CT48 OC X 4 CT49 OC Y 3 CT50 OC Z 1 CT51 OC W 1 CT52 OC Z 0 10 50 OC A + Y 2 51 OC A + Y 0 52 OC A + Z 0 53 OC A + W 0 CT53 OP B 0 15 CT54 OP X 4 CT55 OP Y 3 CT56 OP Z 1 CT57 OP W 1 CT58 OP A 0 20 54 OP A + X 4 55 OP A + Y 3 56 OP A + Z 1 57 OP A + W 1

Table 11 25 Example Surface Treatment Evaluation _ (mixture for 5 min.) _

Ct59 TB 0 CT60 T X 4 CT61 T Y 3 30 CT62 T Z 1 CT63 T W 1 CT64 TA 0 58 T A + X 2 59 T A + Y 0 35 60 T A + Z 0 61 T A + W 0 3900076 - 28 -

Table 11 - continued

Example Surface Treatment Evaluation ___ (mixture for 5 min.) _ CT65 PR B 0 5 CT66 PR X 4 CT67 PR Y 2 CT 68 PR 2 1 CT69 PR W 1 CT70 PR A 0 10 62 PR X 2 63 PR Y 0 64 PR Z 0 65 PR A + W 0

Table 9 shows that at low concentration (eg 0.002%) chlorhexidine the discoloration of the dental restorative material, the teeth and the prosthetic resin is reduced when the surface thereof is first treated with a certain polymer. Furthermore, it appears (examples 46-49) that when the surfaces are treated with a chlorhexidine solution then with Polymer 93W, the discoloration is reduced to the level of the controls.

Table 10 gives the results obtained when treating Occlusin and Opalux surfaces with mixtures of chlorhexidine and Polymer 93W. There is a significant reduction in the coloration of Occlusin to the level of controls at chlorhexidine concentrations of 0.01% and less; the same trend occurs at Opalux.

Table 11 gives the results obtained when treating dental surfaces and a prosthetic resin with a mixture of chlorhexidine and Polymer 93W. The trend in reduction of the discoloration is consistent with that observed with Occlusin and Opalux.

When a tooth with an implantation of Occlusin was subjected to the above-described evaluation, the tooth and the implantation were slightly discolored to the same extent, such that the circumference of the implantation was further reduced.

8800076?

Claims (15)

An oral hygiene composition containing (1) an effective amount of at least one cationic anti-bacterial agent; and (2) an effective amount of at least one polymer, which has pendant polyoxyalkylene oxide side chains. The oral hygiene composition of claim 1, wherein the cationic antibacterial agent is a polybiguanide or a salt thereof. Oral hygiene composition according to claim 2, wherein the polybiguanide is a bis-biguanide. The oral hygiene composition of claim 3, wherein the bis-biguanide is chlorhexidine. Oral hygiene composition according to claim 1, wherein at least one polymer contains one or more repeat units with the general structure A shown under 3 on the formula sheet and one or more repeat units with the general structure B shown on the formula sheet under 4, wherein X, which in the repeat units of structure A may be the same or different and Y, which in the repeat units of structure B may be the same or different, are hydrocarbyl or substituted the hydrocarbyl residues which provide a hull for the polymer; The oral hygiene composition of claim 5, wherein, when 12 is -CHR -CHR, both R and R are hydrogen. The oral hygiene composition of claim 5, wherein 3 R is methyl. An oral hygiene composition according to claim 5, wherein, in structure A, L is a direct bond, 35 -ch2-, -CH2-CH2-, -CH2-CH = -NH-CO-, -C0NHCH (CH2) - or - CONHCH (OH) - The oral hygiene composition of claim 5, wherein, in structure A, p is 1 or 2. 8900078. - 31- * The oral hygiene composition of claim 5, wherein, in structure B, M is -COO- or CONH-. The oral hygiene composition of claim 5, wherein, in structure B, q is 1 or 2. The oral hygiene composition of claim 5, wherein in A or B represent the repeat unit obtained by the addition polymerization of a polymerizable olefinically unsaturated carboxylic acid or an ester or amide derivative thereof, respectively. 12. Z xs -CHR -CHR - or - (CH.) -; where, when Z is -CHR -. 2 m CHR - R, which may be the same or different in the same repeat unit of structure B (when n or q is 2 or more) or in different repeat units of structure B, hydrogen or a hydrocarbyl group; and 2 R, which may be the same or different in the same repeat unit of structure B (when n or q is 2 or more) or in different repeat units of structure B, is hydrogen or 1 2 a hydrocarbyl group; with the proviso that R and R in a single unit -CHR 1 -CHR 2 -— cannot both be hydrocarbyl; 3 R, which may be the same or different in the same repeat unit of structure B 35 (when q is 2 or more) or in different repeat units of structure B, is hydrogen or a hydrocarbyl group or an acyl group, from an alkanoic acid with 8900076. - 30 to five carbon atoms; m, if present, is a number from 2 to 10; n is a number from 1 to 60; p is a number from 1 to 4; and 5 q is a number from 1 to 4; each CO 2 H group through an intermediate or intermediates L is united with the hydrocarbyl residue X, and in the cases where p is 2 to 4, it may be joined by L with the same or different carbon atoms of X; 10. in the repeat units of structure A may be the same or different and is selected from one or more direct bonds and one or more groups of atoms, each group providing a chain of one or more atoms for connecting a (CO 2 H ) group with X, it being understood that more than two (CO 2 H) groups cannot be directly linked to the same carbon atom in X; 3 each (ZO) R) group through one intermediate or intermediates n q M is united with the hydrocarbyl residue Y and in the cases where q is 2 to 4, it may be united by M with the same or different carbon atoms of Y; 20. in the repeat units of the structure B can be the same or different and is selected from one or more direct bonds and one or more groups of atoms, each group providing a chain of one or more atoms for connecting a (SO) group with n Y, provided that more than two (SO) groups cannot be directly linked to the same carbon atom in Y; the ratio of the number of -CO2H groups and the number of (ZO) groups, especially when Z is -CH2CH2-, is in the range of 1:20 to 20: 1. The oral hygiene composition of claim 12, wherein the polymerizable olefinically unsaturated carboxylic acid is acrylic acid or methacrylic acid. The oral hygiene composition of claim 1, which contains a pharmaceutically acceptable carrier which is water, ethanol, a wetting agent, a gelling agent, a gel stabilizer, a sweetening agent, a preservative, a surfactant or an approved colorant or flavoring agent. An oral hygiene composition according to claim 1, in the form of a mouthwash, rinse, irrigation solution, gel toothpaste, dental cleaner, coated dental floss, coated or impregnated toothbrush bristles, inter-tooth stimulator or coating, chewing gum, tablets, breath freshener, foam or spray. -o-o-o-o-o- 8900076.