KR19990062949A - Precipitated Silica Containing Active Ingredients - Google Patents

Abstract

Precipitated silicas containing the active ingredient and delayed release of the active ingredient are prepared by addition of the active ingredient during the production of the precipitated silica by known methods.

Precipitated silica can be added to oral hygiene agents such as toothpastes, topical fluoride preparations, dental materials or medical chewing gums.

Description

Precipitated Silica Containing Active Ingredients

The present invention relates to precipitated silicas containing the active ingredient, methods for their preparation and their use in oral hygiene.

Fluoride ions play an important role in preventing tooth decay. Therefore, in order to prevent the spread of caries, fluoride ions are added to drinking water, among others.

Another way to use fluoride ions to get rid of tooth decay is to use a toothpaste containing fluoride ions (see Oral Hygiene products and Practice by Morton Pader in Cosmetic Science and Technology Series, Vol. 6, pages 383). et seq. (1998), Marcel Dekker, Inc.). For this purpose, it is known that fluoride ions can be added to the toothpaste in the form of NaF, MFP, aminofluoride, tin fluoride and the like. In addition, these toothpastes may contain precipitated silica having an abrasive effect and / or a thickening effect (see WO 93/24103). However, the availability of fluoride ions in the oral cavity is substantially limited to a short time during tooth cleaning.

It is known that hydrofluoric acid can be added to an aqueous slurry of silica gel or xerogel. This slurry is then mixed by addition of a toothpaste preparation component, calcium chloride in them (see DE-A 24 16 742). When treated with hydrofluoric acid, Si-F bonds are formed on the silica gel, which means that the cations (eg, calcium ions) are less adsorbed on the silica gel. The formation of fluorine anions and their controlled release in toothpastes are not described in DE-A 24 16 742.

It is known that pyrolytic silicon dioxide containing 1 to 5% of adsorbed fluoride can be incorporated into toothpastes. These toothpastes always contain 800 to 1200 ppm of free fluoride available for proper therapeutic treatment (see US-A 4 172 121). Pyrolytic silicon dioxide in these toothpastes not only provides a medium containing fluoride ions, but also acts as a thickener to provide the pastey consistency required for the toothpaste.

Pyrolytic silica containing fluoride is prepared by treating pyrolytic silica with HF gas according to US Pat. No. 4 054 689.

Precipitated silicas containing fluoride are known to be prepared by introducing sodium fluoride and oxalic acid into an aqueous vessel and then precipitating the precipitated silica by simultaneously adding sodium silicate solution and sulfuric acid (DE-B 12th). 93 138).

By adding sodium fluoride and oxalic acid, iron ions are complexed to the precipitation mixture to obtain precipitated silica containing low concentrations of iron. Sodium fluoride is not adsorbed on precipitated silica.

An important factor in improving the efficacy of oral hygiene preparations is believed to be to maintain the concentration of the active ingredient in the oral cavity as long as possible, especially after the simultaneous release of the active ingredient. It is an object to improve the retention of the active ingredient so that the required effect can be obtained even with the active ingredient of a weight loss. Undesired effects due to high concentrations should be largely eliminated in this way.

For example, the active ingredient fluoride, which has been demonstrated in several clinical and epidemiological studies, has been shown to have anti-caustic effects, suggesting that carbohydrates can be well protected at very low concentrations (see, for example, Y. Ericson, J.). Dent.Res. 59 (DII): 2131 (1980); O. Backer Dirks, W. Kunzel and JP Carlos, Caries Res. 12 (Suppl. 1): 7 (1978); A. r. Volpe, in a textbook of Preventive Dentistry (RC Caldwell and RE Stallard, eds.), Saunders, Philadelphia, 1997, chap. 12).

It has also been pointed out that the frequency of use of fluoride, i.e. at the appropriate time and place, is more important than the concentration of fluoride under acid attack conditions (see Oral Hygiene Products and Practice by Morton Pader in Cosmetic Science). and Technology Series vol. 6, pages 383 et seq., (1988), Marcel Dekker, Inc.).

These findings have driven the need for research to be directed to minimize fluoride concentrations while maximizing fluoride duration. In addition, toxicological aspects (eg, due to fluorinated drinking water, mouthwash, toothpaste, topical fluoride preparations, fluoride tablets, etc.) for increased dosage of fluoride or increased accumulation of fluoride It should not be ignored.

In the case of active anti-plaque ingredients, in vitro and in vivo studies have shown that the focus of the improved effect stems from improved retention of the active ingredient. Thus, for example, plaque is well inhibited by chlorhexidine, mainly because it retains the active ingredients in the oral cavity and causes them to be gradually released from the plaque matrix and mucosa. In early studies, long-lasting antimicrobial effects were detected by rinsing the mouth once and then measuring the number of bacteria in saliva (see literature; Kornmann: Antimicrobial agents, in Loe, H Kleinmann DV: Dental Plaque control measures and oral hygiene practices, Oxford / Washington, IRL press, 121-142, 1986; P. Germo, P. Bonesvoll, G. Rollas: Relationship between plaque inhibiting effect and retention of Chlorhexidine in the oral cavity.Arms Oral Biol. 19: 1031-1034, 1974 : WR Roberts, M. Addy: Comparison of the bisguanidine antiseptics, alexine and chlorhexidine: i Effects in plaque accumulation and salivary bacteria.J. Clin.Periotontol. 8: 8 213-219, 1981).

Another example is triclosan (2,4,4'trichloro-2'-hydroxydiphenyl ether), which is distinct only when mixed with a (polyvinylmethylether / maleic acid) copolymer that improves the retention of triclosan. Plaque-inhibitory effect (see, American Journal of Dentistry, vol. 2, Special Issue, September, 1989: Report on the use of Triclosan / Copolymer Dentifrices in the Control of Plaque and Ginginitis).

It is known that silica is a highly dispersed component that can be stored in fissures, fine cracks and tubules on the tooth surface. Exposed dentin tubules are blocked by silica in this way, resulting in a desitising effect (see M. Addy, P. Mostafa and R. Newcombe, Dentine Hypersensitivity: A Comparison of five toothpastes used during a six -week treatment period; British Dent. J. 163, 45-50, 1987).

Therefore, it can contain active ingredients as oral hygiene, which satisfies all requirements regarding resistance, abrasiveness, rheology, sensory properties and optical properties, and the active ingredients are fixed to the oral cavity to control and release them over a relatively long period of time. There is a need to provide precipitated silica that can.

1 shows the fluoride release kinetics in silica according to Example 1 as a function of fluoride content (ppm) over time of measurement.

2 shows the pH kinetics in silica according to Example 1 as a function of pH over time of measurement.

The present invention provides precipitated silicas containing the active ingredient and characterized by the delayed release properties of the active ingredient.

Precipitated silica containing the active ingredient is preferably

-Concentration of active ingredient

Can be characterized by the release kinetics of the active ingredient.

In a preferred embodiment, the precipitated silica according to the invention may have the following physicochemical parameters:

Humidity (%)-1 to 10, preferably 1 to 7

pH-2.5 to 8.5, preferably 6 to 8

N ₂ surface area (m 2 / g)-25 to 800, preferably 25 to 400

Average particle size (Malvern) (μm)-2 to 100, preferably 2 to 20.

In addition, the present invention provides the preparation of precipitated silica by known methods, in which the active ingredient, which is suitably soluble or poorly soluble in water, is placed in a precipitation receiver or precipitate suspension, or dried with precipitated silica paste which is optionally redispersed by washing, Provided is a process for producing precipitated silica which may contain the active ingredient according to the invention, characterized in that it is ground simultaneously with the dried material.

The preparation of amorphous silica has been described in several ways. A common property of all methods is that the alkali metal silicate solution is reacted with an inorganic acid or CO ₂ while maintaining certain precipitation conditions (eg, temperature, time, pH and solids content in the precipitation suspension). Thereafter, further acid is added to lower the pH. The mixture is continuously stirred during the precipitation and acidification steps. The suspension is filtered and the filter cake is washed, dried and milled.

The amorphous silica according to the present invention is prepared by a process for preparing precipitated silica by known methods, wherein the active ingredient, suitably soluble (0.1 to 1.0 mole) or poorly soluble (less than 0.1 mole) in water, is added to the precipitation receiver or precipitate suspension. Either loaded, rinsed and dried with optionally re-dispersed silica paste, or simultaneously ground with the dried material.

For example, alkali metal fluorides, alkaline earth metal fluorides or fluoropertites can be used as the component containing fluoride ions, where addition of alkaline earth metal ions can also bind the fluoride from the alkali metal compound. Can be. In addition, chlorhexidine, trichloric acid, hydroxyethane-1,1-diphosphonic acid, alkali metal pyrophosphate, zinc citrate, etc. are mentioned as an active ingredient.

Precipitated silica can be prepared by the methods described in documents DE-A 44 23 493, DE-AS 14 67 019 and EP-B 0 272 380.

It has now been found that the preferred form of preparation comprises placing the active ingredient in a precipitation receiver or spray dried feed. This ensures the most uniform and finest distribution of the final product and ensures maximum retention effect. The therapeutically effective amount of fluoride is from 0.001 to 10%, preferably from 0.005 to 1.0%. The amount of triclosan is 0.1 to 1.0%, preferably 0.2 to 0.5%.

Thickening, abrasive or bifunctional silicas are suitable as silica carriers. Synthetic amorphous silica as described in EP 0 643 015 is preferred, which is available from Degussa AG under the trade name Sident ^R. Zeodent silica (manufactured by JM Huber Corporation, Chemical Division, Havre de Grace, Maryland), Tixosil silicas, manufactured by Rhone-Poulenc CHimie Les Mirroirs, La Defense 3 F-92400 Courbevoie, Sorbosil Sorbosil silicas, Crofield Chemicals, Warrington Cheshire, England, or Siloid silica, Grace Co., Davison Chem. Division, may also be used.

Precipitated silicas, which may contain the active ingredient according to the invention, preferably contain water and the active ingredient in a precipitation vessel and heat the mixture to a temperature of 50 to 100 ° C., preferably 80 to 90 ° C. Adjust the pH and alkali metal concentration by adding sodium silicate solution while maintaining, and then add the sodium silicate solution and sulfuric acid while keeping the pH and alkali metal concentration constant, or add sulfuric acid on the other hand to make the pH desirable. Is acidified to 7, optionally stirred again, filtered, washed to redistribute the filter cake to contain no salt, and dried by spray drying to obtain the granular silica obtained.

Commercially available sodium silicate solutions may have a concentration of 26.8% SiO ₂ and 7.85% Na ₂ O and have a density of 1.352 g / ml.

The concentration of sulfuric acid can be 50 to 96%.

Silicas according to the present invention can be used in oral hygiene preparations such as toothpastes, medical chewing gums and topical fluoride preparations, as well as dental materials in conventional manner known to those skilled in the art. In this case, they can replace all or part of the silica that was previously conventionally used. Preferred areas of use are the toothpaste field. However, gel formulations may also be prepared in combination with any other soluble active ingredient.

Dental care agents according to the invention can be used in accordance with one or more of the raw materials used in accordance with the prior art, for example water, binders (for example carboxymethyl cellulose and its alkali metal salts, in particular sodium salts, hydroxy). Cellulose derivatives such as alkyl cellulose, xanthan gum, travacanth gum, carrageate, alginate and arabic gum, etc.), polishing substances (e.g., pyrolytic precipitated silica, dicalcium phosphate, chalk, hydroxides). Aluminum, etc.), humectants (e.g. glycerol, sorbitol, propylene glycol, low molecular weight polyethylene glycol, 1,4-butanediol, xylitol, etc.), fragrances, surfactants (e.g. alkyl sulfates, sodium lauryl sulfate , Sarcosides, taurine fatty acid amides, monoglyceride sulfates, betaines, etc.), colorants and / or titanium dioxide, sweeteners, buffers, bases or acids, rooms It may contain the active ingredient and.

Dental care agents are prepared according to the prior art. The ingredients are mixed in a suitable form, swelled and dispersed.

Precipitated silicas according to the invention can be used as additives in toothpastes, in particular as thickening and / or abrasive ingredients which release the active ingredient.

Precipitated silica according to the invention has the following advantages:

The silica according to the invention is used as a carrier for dental active ingredients which stores the active ingredient at the site of action and releases it in small amounts over a relatively long time (deposition effect, controlled release). Thus, silica acts as an active ingredient reservoir containing the active ingredient in adsorbed, absorbed or chemisorbed form. Any form of silica (eg precipitated silica or silica gel or pyrolytic silica) can be used. Any poorly soluble fluoride (eg CaF ₂ ) and poorly soluble active ingredient (eg triclosan or chlorhexidine) can be used as the active ingredient.

By mixing the poorly soluble active ingredient with the readily soluble active ingredient (eg, NaF, monofluorophosphate, etc.), the release kinetics of the active ingredient combining the direct and deposition effects can be precisely controlled. The advantages of the silicas according to the invention are based on improved therapeutic efficacy due to longer time effectiveness (e.g. increased prevention of caries due to improved dental resistance to mineral loss). This means that even a small amount of active ingredient is possible, which is expected to have little side effects and low toxicity. Adding fluoride to drinking water (medical mandates) may be unnecessary.

Example

Possible alternatives to the process for the preparation of precipitated silica according to the invention are described in the Examples with respect to the step of doping with fluoride.

Manufacturing Method 1

Fluoride salts in the precipitation receiver + alkaline earth metal chlorides at the end of precipitation

Manufacturing Method 2

Fluoride salts + alkaline earth metal chlorides at the end of precipitation

Manufacturing Method 3

Fluoride Salts in Precipitation Receptors

Manufacturing Method 4

Fluoride Salts in Spray Dry Feeds

Preparation of Abrasive Precipitated Silica Containing Fluoride Ions

Example 1 (Fluoride-containing abrasive silica)

Substantially according to DE-A 44 23 493, in Example 1 the precipitation is carried out by adding CaF ₂ to the precipitation receiver.

12.8 L of water and 52.8 g of CaF ₂ are initially introduced with indirect heating into a 50 L settling vessel with stirring and then heated to 85 ° C. While maintaining the temperature, a small amount of sodium silicate solution (26.8% SiO ₂ and 7.85% Na ₂ O, density 1.352 g / ml) is added to adjust the pH to 8.5. Thereafter, sufficient sulfuric acid (50% concentration) and water glass (composition as described above) to keep the pH constant at 8.5 were added to 60.0 ml per minute to continue precipitation for 240 minutes. The suspension obtained is then acidified with sulfuric acid (50% concentration) such that the pH is 7 or less.

The reaction mixture is stirred for another 60 minutes, filtered, washed free of salts, and dried in a spray drier. Thereafter, the product is ground.

The precipitated silica obtained has the following physicochemical properties:

Humidity (%) 3.2

pH 8.0

Conductivity (μS / cm) 400

N ₂ surface area (㎡ / g) 31

Average particle size (Malvern) (μm) 10.2

Fluoride Ion Concentration (%) 0.5

Example 2 (Comparative Example, Abrasive Silica-Free Silica)

Abrasive precipitated silica is prepared according to DE-A 44 23 493, Example 1 without the addition of fluoride.

Example 3 (fluoride-containing precipitated silica with a thickening effect)

The process is carried out according to EP 0 272 380 B1, Example 1.

73 liters of hot water and 5.25 liters of sodium silicate solution (density 1.353 g / ml, modulus SiO ₂ : Na ₂ O = 3.46) are heated to 85 ° C. with stirring in a rubber-lined 120 liter capacity precipitation vessel. 16.5 L of sodium silicate solution (composition as above) and 1.448 L of sulfuric acid are added simultaneously to the alkaline precipitation mixture over 90 minutes with stirring at constant temperature.

The precipitated silica suspension obtained is then adjusted to pH 3.5 with sulfuric acid (96% concentration), which is achieved by flowing the acid for a few minutes at a rate of 1.25 l / hour. The solids content of the precipitated silica suspension obtained in this way is 85.0 g / l.

After filtration and washing, the remaining low salt paste obtained was stirred with vigorous stirring, water and layered CaF ₂ were added to a concentration of 0.5 weight percent based on the amount of silica to convert into a spray suspension, spray dried and air dried. Grinding in an air-jet mill.

Example 4 (Comparative Example, Precipitated Silica without Fluoride with Thickening Effect)

The process is carried out according to EP 0 272 380 B1, Example 1 without adding CaF ₂ .

Toothpaste formulations using precipitated silica according to Examples 1-4

Toothpaste 1 (%) Toothpaste 4 (%)

Demineralized Water 30.60 31.60

CMC 1.20 1.20

Sorbrol M Na 0.20 0.20

Saccharin Na 0.10 0.10

Titanium Dioxide 0.40 0.40

Sorbitol (70% concentration) 40.00 40.00

Silica 25.00 22.00 according to Example 1

Aerosil 200-2.00

Aromatic Oils 1.00 1.00

Blowing agent 1.50 1.50

Toothpaste 2 (%) Toothpaste 5 (%)

Demineralized Water 33.60 33.60

CMC 1.20 1.20

Sorbrol M Na 0.20 0.20

Saccharin Na 0.10 0.10

Titanium Dioxide 0.40 0.40

Sorbitol (70% concentration) 40.00 40.00

Silica 14.00-according to Example 1

Silica according to Example 2-14.00

Silica according to Example 3-8.00

Silica 8.00-according to Example 4

Aromatic Oils 1.00 1.00

Blowing agent 1.50 1.50

Toothpaste 3 (%) Toothpaste 6 (%)

Demineralized Water 39.60 39.60

CMC 1.20 1.20

Sorbrol M Na 0.20 0.20

Saccharin Na 0.10 0.10

Titanium Dioxide 0.40 0.40

Sorbitol (70% concentration) 40.00 40.00

Silica 5.00-according to Example 1

Silica according to Example 2-5.00

Silica according to example 3-11.00

Silica 11.00-according to Example 4

Aromatic Oils 1.00 1.00

Blowing agent 1.50 1.50

Toothpaste 7 (%) Toothpaste 10 (%)

Demineralized Water 7.95 12.45

CMC 0.50 0.50

Colorant (1% concentration) 0.50 0.50

Sorbrol M Na 0.15 0.15

Saccharin Na 0.20 0.20

Polyethylene Glycol 400 3.50 3.50

Sorbitol (70% concentration) 40.00 40.00

Glycerol 20.00 20.00

Silica 25.00 18.00 according to Example 1

Aerosil 200-2.50

Aromatic Oils 1.00 1.00

Blowing agent 1.20 1.20

Toothpaste 8 (%) Toothpaste 11 (%)

Demineralized Water 10.95 10.95

CMC 0.50 0.50

Colorant (1% concentration) 0.50 0.50

Sorbrol M Na 0.15 0.15

Saccharin Na 0.20 0.20

Polyethylene Glycol 400 3.50 3.50

Sorbitol (70% concentration) 40.00 40.00

Glycerol 20.00 20.00

Silica 14.00-according to Example 1

Silica according to Example 2-14.00

Silica according to Example 3-8.00

Silica 8.00-according to Example 4

Aromatic Oils 1.00 1.00

Blowing agent 1.20 1.20

Toothpaste 9 (%) Toothpaste 12 (%)

Deionized Water 11.95 11.95

CMC 0.50 0.50

Colorant (1% concentration) 0.50 0.50

Sorbrol M Na 0.15 0.15

Saccharin Na 0.20 0.20

Polyethylene Glycol 400 3.50 3.50

Sorbitol (70% concentration) 40.00 40.00

Glycerol 25.00 25.00

Silica 5.00-according to Example 1

Silica according to Example 2-5.00

Silica according to example 3-11.00

Silica 11.00-according to Example 4

Aromatic Oils 1.00 1.00

Blowing agent 1.20 1.20

Determination of fluoride release kinetics as deposition effect point and pH kinetics as a function of time, using precipitated silica according to Example 1

See FIG. 1 (fluoride emission kinetics) and FIG. 2 (pH dynamics)

Amount of fluoride based on precipitated silica pH 2 minutes later 0.479 ppm 7.95 5 minutes later 0.767 ppm 7.91 15 minutes later 1.62 ppm 7.71 30 minutes later 2.24ppm 7.59 45 minutes later 2.86 ppm 7.42 60 minutes later 3.62ppm 7.29 120 minutes later 4.64ppm 7.09 150 minutes later 5.08 ppm 7.01 180 minutes later 5.28ppm 6.96 After 240 minutes 5.48ppm 6.91 After 300 minutes 5.73ppm 6.87 After 360 minutes 5.80ppm 6.84 24 hours later 7.09ppm 6.86 25 hours later 7.06ppm 6.79 26 hours later 6.89ppm 6.75 48 hours later 7.64ppm 6.73 49 hours later 7.49ppm 6.69 50 hours later 7.43ppm 6.67 51 hours later 7.40ppm 6.65

Calculated Value Using the Table Above

Total Fluoride In Test Suspension [F ^-] tot. 50 ppm Soluble fluoride [F ^-] sol. 7.8ppm Released fluoride sol. F ^- [%] 97.9

The amount of fluoride deposited in the silica according to the invention according to Example 1 is 5 mg F '/ g of silica per 50 ppm of test suspension. Based on the solubility of CaF ₂ , 7.8 ppm thereof is soluble. This experiment demonstrates that 97.9% of the soluble fluoride is released within 2 days.

Determination of Total Fluoride Content in Silica

The total fluoride content in silica is measured using thermohydrolysis and ion chromatography.

Silica according to Example 1 Experiment result[%] 0.51 ± 0.02

The results show that the total theoretical amount of fluoride used [5 mg F / g precipitated silica (g) (0.5 wt.%) Adhered to the precipitated silica.

Cleaning test in molar and surface analysis using XPS / SIMS

Using precipitated silica according to the invention, according to Example 1, it is shown that fluoride ions are stored on the surface of the tooth after a single cleaning process.

parameter Tooth 1 Tooth 2 Tooth 3 grinding Tooth surface polished Tooth surface polished Tooth surface polished First surface analysis (= initial state before cleaning) Analysis by XPS / SIMS Analysis by XPS / SIMS Analysis by XPS / SIMS Preparation of Toothpaste / Cleaning Suspension Homogenize suspension of Goat tooth decay toothpaste 1: 1 in water Standard paste A containing 20% silica according to Example 1 was dispersed 1: 1 in water Standard paste B containing 20% silica and 100 ppm CaF ₂ according to Example 2 was dispersed 1: 1 in water. Cleaning process Clean with an electric toothbrush for 5 minutes on a vibrating table Clean with an electric toothbrush for 5 minutes on a vibrating table Clean with an electric toothbrush for 5 minutes on a vibrating table

X-ray photoelectron spectroscopy (XPS)

The XPS technique based on the principle of the optoelectronic effect [1-4] is used to measure the surface composition of the tooth before and after treatment with the fluoride. Because XPS has a high surface specificity, the process is specifically analyzed at the outermost few nanometers, which is the boundary region where F is incorporated and chemical attack or polishing on enamel occurs.

The analysis covers only the outermost part of the atom, optionally the region in which fluoride is incorporated or eluted. Although the analysis is carried out up to several atomic layers of the substance, the analysis spot is especially relevant for the entire tooth, which can eliminate the microinhomogeneity effect from the analysis and the relevant macroscopic effects on the entire surface of the tooth. Data is obtained. Thus, the XPS method is about 1000 times more surface-sensitive than the energy dispersive X-ray analysis (EDX) technique used in electron microscopy.

The XPS method offers the advantage of effective quantifiability. In particular, it also provides data relating to the state of chemical bonding of enamel or dentin surfaces. Thus, XPS is an internationally recognized measurement method for dental research and dental clinicians (especially in the United States) to understand Ca's complexation behavior, Ca / P ratios on teeth or dentin surfaces, and effects due to cleaning agents and primers.

rule :

1. Insert

The molar tooth is inserted into the XPS test unit (Leybold LHS12) without further pretreatment. The apparatus used consists of several vacuum chambers. In the first chamber, the molar is gently moved from atmospheric to pre-vacuum conditions (about 10 ^-2 mbar, oil-free rotary disk-type pump vacuum), in particular organic and easy to remove moisture and other desorption from dentin Remove the ingredients. Thereafter, the approximately predried tooth is transferred to the manufacturing chamber. In this chamber, the material is placed under high or ultra high vacuum conditions (10 ^-7 to 10 ^-8 mbar, turbopump vacuum). In the meantime, a residual gas quadrupole mass spectrometer is used to test whether volatile residual components (particularly water) escape from the material under these extreme conditions. The pumping down process is performed only at room temperature. Thus, no bite force is applied to the teeth in any other way. Samples conditioned in this way are finally transferred to the actual assay chamber (base pressure; 6-8 × 10 ⁻¹⁰ mbar, turbopump, getter-ion pump and Ti sublimation pump vacuum).

2. Measuring method

Soft X-radiation (MgK _α radiation, 1253.6 electron volts, power 200 watts) is applied to the tooth surface over the entire surface of the tooth under ultra-high vacuum conditions. This initiates the light emitting process. Electrons (eg, F1s, Ca2p, P2s, C1s, O1s, etc.) are emitted. Due to the selected stimulus energy, photoelectrons with ultrashort average glass paths in the solid are emitted. Thus, this method is specific to the topmost region of the atom, i.e., in the case of oxidative minerals such as hydroxypertite / fluoropertite, the top two nanometers are optionally involved.

Only electrons emitted directly from the surface of the material can leave the material and act as data carriers. The power energy of the emitted electrons is measured using a hemispherical energy analyzer (CHA, Leybold EAllA). The binding energy of the photons off the surface atoms of the tooth is measured from the difference between the measured energy and the irradiated X-ray photon energy. Despite the high surface specificity, only about 1.5 cm 2 of surface area can be assayed and can be analyzed integrally using an optical microscope and a control laser. Therefore, microuniformity becomes an average value.

3. Evaluation

1. Surface concentration

The measured XPS spectrum is processed with a suitable polynomial and subtraction program to remove the so-called X-ray adjacent signal. After that, all elements (except H and He) detected in XPS are identified. Background subtraction is performed using the Shirley method [5] taking into account element-specific relative sensitivity factors and then quantified.

2. Coupling status

Based on the binding energy value, the chemical bonding state of the element can be measured. Thus, for example, carbonate carbon and carbon combined with aliphatic may differ in concrete. In the qualitative analysis of this important embodiment, sample-specific electrostatic charges on poorly conductive materials should be considered by internal reference procedures or compensation techniques.

references;

[1] K. Siegbahn et al., Nova Acta Reg. Soc. Sci. Ups. Ser. IV vol. 20 (1967)

[2] Practical Surface Analysis, Ed. D. Briggs, M. P. Seah, Second Edition, 1990, John Wiley, Chichester and Salle + Sauerlander, Aarau

[3] J. F. Moulder, W. F. Stickle, P. E. Sobol, K. D. Bomben, Handbook of X-ray Photoelectron Spectroscopy, Ed. J. Chastain, Perkin Elmer, Physical Electronics Division, Eden Prairis, Mi, USA, 1992)

[4] R. Holm, S. Storp, Methoden zur Untersuchung von Oberflachen, Ullmanns Enzyklopadie der technischen Chemie, vol 5, Verlag Chemie, Weinheim, 1980, pp. 242-256

[5] D. A. Shirley, Phys. Rev. B 5, 1992, 4709

Formulation of Rifenwert Standard Paste Used

Raw Material Standard Paste A [%] Standard Paste B [%]

1 Demineralized water 34.54 34.54

2 CMC, Blanos 7 MCF 1.00 1.00

3 Preservative, Sorbrol M 0.20 0.20

4 Sweeteners, Saccharin 0.10 0.10

5 CaF ₂ - 0.21

6 paraffin oil 0.50 0.50

7 Sorbitol 40.00 40.00

8 aromatic oils 1.00 1.00

Silica According to Example 2 According to Example 1

Precipitated Silica 20% Precipitated Silica 20%

Preparation of Standard Pastes A and B

The binder (CMC) is swelled in water in a Retsch mill RM1 and then components 3-8 are mixed and homogenized. While carrying out the shoe grinding operation, 160 g of the obtained mixture are weighed respectively, and 40 g of the specific precipitated silica according to Example 1 or 2 are added, respectively. After completion of the precipitated silica incorporation, the paste is homogenized three times in a precision triple roll mill.

Toothpaste / detergent suspension manufacture

Standard pastes A and B and colgate bifluoride are then diluted 1: 1 with water and dispersed in a 400 ml beaker for 5 minutes at 1500 rpm using a double blade stirrer.

Description of the cleaning process

The silica-containing toothpaste suspension is placed in a cleaning device, and the human tooth (molar tooth) whose polished chewing surface is cleaned with an electric toothbrush (Broxodent). The vibration table used in the cleaning apparatus is adjusted to 60 vibrations / minute to avoid the formation of fragments. After the cleaning process, the teeth are rinsed and dried with running water free of fluoride and the surface is analyzed.

In a comparative example, a colloidal bifluoride, a toothpaste commercial product, was also tested.

Test result Tooth 1 Colgate Bifluoride Tooth 1 Colgate Bifluoride Tooth 2 Standard Paste A Tooth 2 Standard Paste A Tooth 3 Standard Paste B Tooth 3 Standard Paste B Condition of human teeth, chewing surface grinding washing grinding washing grinding washing Surface% of fluoride, first feature 0.68 1.04 0.45 0.91 0.46 0.69 Δ%, first point +0.36 +0.46 +0.23 Repeated measurement Condition of human teeth, chewing surface grinding washing grinding washing grinding washing Surface% of fluoride, second point 0.33 0.75 0.41 0.91 0.35 0.33 Δ%, first point +0.42 +0.50 -0.02

Surprisingly, using these results, in standard paste A, the silica according to the invention from example 1 contains standard pastes B and NaF, NaMFP and calcium with abrasive silica and CaF ₂ alone added and long-lasting effect It can be shown that it causes significantly higher fluoride deposition after a one-time cleaning process than colgate bifluoride, a toothpaste that represents. This is expected to improve tooth resistance to mineral loss. At the same time, the fluoride release kinetics described in Figure 1 below suggest that fluoride is delayed release over days at 37 ° C in vivo.

Colgate toothpastes containing nonfluoride and calcium are commercially available. It contains the following components;

Dicalcium phosphate, water, glycerol, sorbitol, cellulose gum, sodium lauryl sulfate, flavoring agent, tetrasodium pyrophosphate, sodium saccharin, sodium monofluoro phosphate, sodium fluoride.

Determination of Fluoride Release Kinetics of Silica Topping with Alkali and Alkaline Earth Fluoride

Fluoride release in fluorine-containing silica is tested throughout the period of using this method. Therefore, it can be determined whether the silica has an adhesive effect.

Measurements are made using ion-selective electrodes and ion analyzers. For example, alkali metal and alkaline earth metal salts are used to dope the fluoride.

2) Devices and Reagents

2.1) device

Analytical Balance, Sartorius A 200 S

Spatula

250 ml plastic screw cap container

IKa magnetic stirrer with 2 cm stir bar, ES 5

Color thermometer with water bath

ORION pH / mV and ion metering model EA 940

pH electrode

Ion-selective electrodes

2.2) reagents

Distilled water

100 ppm Orion Fluoride Standard Solution for preparing 100 ppm, 50 ppm, 20 ppm calibration solutions

pH buffers: pH 4.0, 7.0 and 10.0

3) stability aspect

NaF is toxic.

R 23/24/25 S 1 / 2-26-44

At acidic pH, released HF is very toxic.

R 26/27 / 28-35 S 2 / 9-26 = 36 / 37-45

4) Detailed description of the experiment

4.1) Preparation of fluoride calibration solution

100 ppm orion fluoride standard solution is diluted 1: 1 or 1: 5 with distilled water for calibration purposes and stored in a 250 ml plastic screw capped container.

4.2) Standardization

Calibrate the ion meter before starting each experimental step. The calibration solutions and buffers mentioned above are used for this purpose. The electrode is washed with distilled water and carefully dried before immersed in the calibration solution. Observe the information provided by the manufacturer of the device while doing so.

4.3) Measurement

100 g of 1% concentration of silica / water suspension is precisely weighed 10 mg into a 250 ml plastic screw capped container. In order to prevent contact with any hydrofluoric acid released, the experiment is carried out in a ventilation chamber.

The suspension is kept constant at 37 ° C. in a water bath, and stirred at a stirring speed 3 using a magnetic stirrer.

Fluoride release is measured using ion-selective electrodes. To this end, according to the manufacturer's information, the membrane of the ion-selective electrode is cleaned with the solution contained in the electrode and then the level is readjusted to the correct level. The electrode is washed with distilled water and dried with a soft cloth. The tip of the electrode is immersed in the suspension and stirred at specific time intervals, and the concentration of fluoride is read and recorded in ppm. The measurement interval is increased from 2 minutes to several hours until the experimental value is constant.

At the same time, the pH of the suspension is measured. The electrode is washed with distilled water and then dried before taking the measurements. The ion analyzer is then switched for pH measurement. The electrode is immersed in the suspension, then the pH is measured and recorded with stirring.

To further measure fluoride concentration and pH, the electrode is immersed in the suspension. It is important to switch according to the specific type of electrode and then read the experimental values.

The fluoride release kinetics is graphically represented as the fluoride concentration over time.

1) After equilibration, record the fluoride concentration over time ([F] _eq , ppm)

2) Theoretical fluoride concentration ([F] _tot , ppm) from 1 g of silica per 100 g of suspension

3) Soluble fluoride concentration from 1 g of silica per 100 g of suspension ([F] _sol , ppm)

4) Data on fluoride concentration ([F] _eq ), recorded as% of soluble fluoride ([F] _sol )

The results show that fluoride-doped precipitated silicas having the same application-oriented properties can be prepared based on precipitated silicas which do not contain fluoride but which have the necessary deposition effect. The examples further show that abrasive silica, thickening silica and bifunctional silica can be used as the active ingredient carrier according to the invention.

Example 3 can be referred to as a representative example coated using four methods, and its deposition effect can also be detected.

Precipitated silicas containing the active ingredient according to the invention can be used in oral hygiene such as toothpastes, topical fluoro formulations, dental materials or medical chewing gums.

Claims (4)

A precipitated silica containing the active ingredient, wherein the precipitated silica is characterized by delayed release of the active ingredient. A method for producing precipitated silica containing the active ingredient according to claim 1 by known methods, in which the active ingredient, which is suitably soluble or poorly soluble in water, is added to the precipitation receiver or the precipitation suspension or washed and optionally redispersed. Drying with silica paste or simultaneously grinding with the dried material. Use of precipitated silica containing the active ingredient according to claim 1 in oral hygiene. 4. Use according to claim 3, wherein the precipitated silica containing the active ingredient is used in oral hygiene as an additive to release fluoride ions.