JP5442501B2 - Coating liquid - Google Patents

Description

The present invention relates to a coating solution used for pharmaceuticals, foods, and the like, and a coated product whose surface is coated with the coating solution.

In food products such as pharmaceutical tablets, gums, and chocolates, a colored film coating is often applied to conceal the color of the edible core material and increase the commercial value. In Japan, there is a tendency that coloring with white color or high brightness is preferred, and a coating solution using hydroxypropylmethylcellulose or the like as a film agent and titanium dioxide as a white pigment is generally used.

Titanium dioxide has a high refractive index and is a white pigment with excellent hiding power, but has a high specific gravity and thus tends to settle in a dispersion. For this reason, the coating liquid which mix | blended titanium dioxide has the problem that a titanium dioxide precipitates during a process or a preservation | save, and coloring becomes non-uniform | heterogenous.

In order to solve such a problem, a method of adding a synthetic hydrotalcite-like compound in an aqueous dispersion phase of inorganic fine particles such as titanium dioxide has been proposed (Patent Document 1).
However, synthetic hydrotalcite-like compounds cannot be used for pharmaceuticals and foods from the viewpoint of safety because they are compounds composed of boron, nickel and the like.

Moreover, in the manufacture of a polysaccharide film containing titanium dioxide, a method of adding an emulsifier such as soybean lecithin to the polysaccharide solution is disclosed (Patent Document 2). However, this method can improve the dispersion of titanium dioxide, but cannot prevent its settling.

Conventionally, hydroxypropyl methylcellulose has been mainly used as a coating agent for colored film coating. In recent years, hydroxypropylcellulose, which has a lower moisture permeability than hydroxypropylmethylcellulose, has attracted attention and has been approved not only as a pharmaceutical product but also as a food additive. However, hydroxypropylcellulose has a drawback that the film strength is weaker than hydroxypropylmethylcellulose.

A plate gum coating method using a coating solution containing titanium dioxide, hydroxypropylcellulose, and reduced palatinose is also disclosed (Patent Document 3). However, reduced palatinose is a sugar alcohol that is extremely difficult to dissolve in water, and has a property that crystals are rapidly precipitated by a subtle temperature change.
Therefore, when used in an aqueous solution, the rate of crystallization of reduced palatinose cannot be controlled arbitrarily in the coating process, and when left at room temperature, the crystals of reduced palatinose grow and the size of the crystal particles varies, resulting in a final product. There is a possibility that a large unevenness is generated on the surface of the surface, and the appearance is remarkably deteriorated. Furthermore, reduced palatinose dissolved in water does not have an effect of preventing the precipitation of titanium dioxide, and the problem of uneven coloring cannot be solved.

Japanese Patent Laid-Open No. 2008-201984 JP-A-5-146271 International Publication No. 97/08958

An object of the present invention is to provide a stable edible coating solution in which precipitation of titanium dioxide does not occur in the coating process, and a coating with high film strength and uniform color.

As a result of diligent research to solve the above problems, the present inventors have found that a stable coating liquid is obtained by dispersing reduced palatinose as solid particles in a system containing reduced palatinose, hydroxypropyl cellulose, titanium dioxide, and water-containing ethanol. As a result, it was found that a coating with a good appearance was obtained, and the present invention was completed.

The reduced palatinose according to the present invention is a disaccharide sugar alcohol obtained by hydrogenation of palatinose, and is an equimolar mixture of α-glucopyranosyl-1,6-D-sorbitol and α-glucopyranosyl-1,6-D-mannitol. is there.
Reduced palatinose is low in calories, excellent in moisture absorption resistance, heat resistance and acid resistance, and has a refreshing sweetness, so it is extremely useful as a pharmaceutical or food material. On the other hand, it is the least soluble in sugar alcohol and has a drawback that the crystallization is difficult to control in the conventional coating liquid preparation method because the solubility changes rapidly with temperature.

The compounding quantity of the reduced palatinose in the coating liquid of this invention is 3 to 25 weight%, Preferably it is 3 to 20 weight%. Since it is necessary to disperse the reduced palatinose of the solid particles in the coating liquid, it is desirable that the particle diameter is small. Specifically, it is preferably 150 μm or less, particularly preferably 100 μm or less.

The hydroxypropyl cellulose according to the present invention is a nonionic cellulose ether obtained by reacting propylene oxide or the like with cellulose. In Japan, it is approved for use in medicines and foods, and is used as a tablet coating agent and binder, a syrup stabilizer, and a jelly base material.

Various hydroxypropyl celluloses having different degrees of polymerization and substitution are commercially available, and can be appropriately selected and used as required. The amount of hydroxypropyl cellulose is 0.1 to 20% by weight, more preferably 1 to 16% by weight.

Titanium dioxide can be used in either a rutile type or anatase type. However, since the coating solution of the present invention is used for ingestion, it is desirable to use a high-purity product that is approved for use in pharmaceuticals or foods.

The amount of titanium dioxide is appropriately adjusted according to the color tone of the core material to be coated, the appearance color of the final product, and the like, but in many cases is about 0.1 to 10% by weight. The particle diameter of titanium dioxide is not particularly limited, but a particle diameter of about 0.2 to 0.4 μm is preferable in consideration of the hiding power.

  Hydrous ethanol is used for the coating liquid according to the present invention. The water content in hydrous ethanol is 5 to 30% by weight. In addition, the compounding quantity of hydrous ethanol is suitably adjusted with the compounding quantity of reduced palatinose, hydroxypropyl cellulose, titanium dioxide, and other components.

In the coating liquid according to the present invention, other components can be blended as necessary. For example, coating agents such as hydroxypropylmethylcellulose, hydroxyethylcellulose, hydroxyethylmethylcellulose, hydroxypropylmethylcellulose acetate succinate, hydroxypropylmethylcellulose phthalate, shellac and zein, plasticizers such as oleic acid, soybean fatty acid, glycerin and propylene glycol, erythritol , Sugar alcohols such as maltitol, sorbitol, mannitol, xylitol, lactitol, and reduced starch saccharified product, pigments such as calcium carbonate, anhydrous silicic acid, calcium phosphate, and talc, various tar dyes, cochineal dyes, caramel dyes, and cacao Pigments such as pigments, sweeteners such as acesulfame potassium, sucralose, stevia and thaumatin, mint oil, silica Perfume such as oil, orange oil, and lemon oil, sucrose fatty acid ester, glycerin fatty acid ester, polyglycerin fatty acid ester, sorbitan fatty acid ester, surfactant such as lecithin, ascorbic acid, riboflavin, pyridoxine, niacin, tocopherol, etc. Amino acids such as vitamins, valine, leucine, isoleucine, lysine, glycine and glutamine.

The coating liquid according to the present invention can be produced by dispersing solid particles of reduced palatinose and titanium dioxide in hydrous ethanol containing hydroxypropylcellulose, reduced palatinose, and titanium dioxide.
A method in which reduced palatinose is pulverized with a hammer mill, pin mill or the like into a fine powder, added to hydrous ethanol in which hydroxypropylcellulose is dissolved and stirred and dispersed with titanium dioxide, and reduced palatinose and titanium dioxide are dissolved in hydroxypropylcellulose. In addition to hydrous ethanol, existing dispersion methods such as a method of pulverizing and dispersing with a homomixer, a colloid mill, a high speed mixer, a sand mill or the like can be employed.

In the coating liquid of the present invention, titanium dioxide is uniformly dispersed, and precipitation of titanium dioxide does not occur even when left at room temperature. When the coating solution is used, the coating strength is high, and a uniform colored coating can be obtained.
The reason why titanium dioxide does not precipitate in the coating liquid of the present invention is not clear, but the solid particles of reduced palatinose form a gentle three-dimensional structure in hydrous ethanol, and the precipitation of titanium dioxide is suppressed. Presumed.
It should be noted that other sugar alcohols such as erythritol, maltitol, sorbitol, and xylitol are easily dissolved in water-containing ethanol and immediately settled even when dispersed as solid particles, so that precipitation of titanium dioxide cannot be prevented.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto.

(Examples 1-5)
Hydroxypropyl cellulose 4% by weight, titanium dioxide 1% by weight, reduced palatinose 3 to 25% by weight, water content 15% by weight hydrous ethanol 70 to 92% by weight 50 ° C. hydrous ethanol in which hydroxypropyl cellulose is dissolved Reduced palatinose and titanium dioxide were added to the mixture, and the mixture was stirred with a homomixer at a rotational speed of 5000 rpm for 5 minutes to prepare 200 g of the coating solutions of Examples 1 to 5.

In the same manner, Comparative Example 1 containing 4% by weight of hydroxypropyl cellulose, 1% by weight of titanium dioxide, and 95% by weight of water-containing ethanol having a water content of 15% by weight, 4% by weight of hydroxypropyl cellulose, 1% by weight of titanium dioxide Comparative Example 2 containing 1% by weight of reduced palatinose and 94% by weight of water-containing ethanol having a water content of 15% by weight, and 4% by weight of hydroxypropyl cellulose, 1% by weight of titanium dioxide, 33% by weight of reduced palatinose, and water content 200 g of a coating solution of Comparative Example 3 containing 15% by weight of water-containing ethanol and 62% by weight was prepared.

Table 1 shows the composition of each coating solution, the presence or absence of titanium dioxide precipitation, the film hardness, and the fluidity of the coating solution. Precipitation was visually observed when the coating solution was allowed to stand at room temperature for 2 hours. The film was prepared by making each coating solution into a thin film using a doctor blade having a thickness of 200 μm and naturally drying at room temperature for 24 hours. The film hardness was determined by a JIS pencil scratch test, and the hardness of the hardest pencil that did not damage the film was defined as the film hardness.

When the coating solutions of Comparative Examples 1 and 2 were allowed to stand at room temperature for 2 hours, precipitation of titanium dioxide was observed. The coating liquid of Comparative Example 3 had poor fluidity and was not suitable as a coating liquid. Further, the film of Comparative Example 1 containing no reduced palatinose had a low hardness.

On the other hand, the coating liquids of Examples 1 to 5 having a reduced palatinose content of 3 to 25% by weight had no titanium dioxide precipitation, and the film hardness and the fluidity of the coating liquid were good. In particular, the coating liquids of Examples 1 to 4 having a reduced palatinose content of 3 to 20% by weight were excellent in film hardness and fluidity of the coating liquid.

(Examples 6 to 9)
Reduction to hydrous ethanol at 50 ° C. in which hydroxypropyl cellulose is dissolved in the range of 8% by weight of hydroxypropyl cellulose, 1% by weight of titanium dioxide, 5% by weight of reduced palatinose, and 86% by weight of hydrous ethanol having a water content of 5 to 30% by weight. Palatinose and titanium dioxide were added, and the mixture was stirred with a homomixer at a rotational speed of 5000 rpm for 5 minutes to prepare 200 g of coating solutions of Examples 6-9.

Coating solutions of Comparative Examples 4 and 5 using the same amount of hydroxypropylcellulose, titanium dioxide, and reduced palatinose, and using the same method and ethanol containing no water and water containing 35% by weight of water containing 86% by weight 200 g was prepared.

Table 2 shows the composition of each coating solution, the presence or absence of titanium dioxide precipitation, and the film hardness. When the coating solutions of Comparative Examples 4 and 5 were allowed to stand at room temperature for 2 hours, precipitation of titanium dioxide was observed. On the other hand, the coating liquids of Examples 6 to 9 in which the water content of the water-containing ethanol was 5 to 30% by weight had no precipitation of titanium dioxide and the film hardness was good.

(Examples 10 to 14)
Hydroxypropyl cellulose was dissolved in a range of 0.1 to 20% by weight of hydroxypropyl cellulose, 1% by weight of titanium dioxide, 5% by weight of reduced palatinose, and 74 to 93.9% by weight of hydrous ethanol having a water content of 15% by weight. Reduced palatinose and titanium dioxide were added to hydrous ethanol at 0 ° C. and stirred with a homomixer at a rotational speed of 5000 rpm for 5 minutes to prepare 200 g of a coating solution of Examples 10-14.

In the same manner, 200 g of a coating solution of Comparative Example 6 comprising 30% by weight of hydroxypropyl cellulose, 1% by weight of titanium dioxide, 5% by weight of reduced palatinose, and 64% by weight of water-containing ethanol having a water content of 15% by weight was prepared.

Table 3 shows the composition of each coating solution, the presence or absence of precipitation of titanium dioxide, the film hardness, and the fluidity of the coating solution. The coating liquid of Comparative Example 6 had poor fluidity and was unsuitable as a coating liquid.

In contrast, the coating liquids of Examples 10 to 14 having a hydroxypropyl cellulose content of 0.1 to 20% by weight have no precipitation of titanium dioxide, and are good in both film hardness and fluidity of the coating liquid. Met. In particular, the coating liquids of Examples 11 to 14 having a hydroxypropyl cellulose content of 1 to 16% by weight were excellent in film hardness and fluidity of the coating liquid.

(Examples 15 and 16)
Hydrous ethanol at 50 ° C. in which hydroxypropylcellulose is dissolved in a composition of 86.5% by weight of hydroxypropylcellulose, 0.5% by weight of titanium dioxide, 5% by weight of reduced palatinose, and 86.5% by weight of hydrous ethanol having a water content of 20% by weight. Reduced palatinose and titanium dioxide were added to the mixture, stirred with a homomixer at a rotational speed of 5000 rpm for 5 minutes, and sieved with 140 mesh (aperture 106 μm) to prepare 200 g of a coating solution of Example 15. The obtained coating liquid was not allowed to precipitate titanium dioxide even when allowed to stand at room temperature for 2 hours.

In a composition of 8% by weight of hydroxypropyl cellulose, 0.5% by weight of titanium dioxide, and 91.5% by weight of water-containing ethanol having a water content of 20% by weight, titanium dioxide was added to water-containing ethanol at 50 ° C. in which hydroxypropyl cellulose was dissolved, The mixture was stirred with a homomixer at a rotational speed of 5000 rpm for 5 minutes, and sieved with 140 mesh (aperture 106 μm) to prepare 200 g of a coating solution of Comparative Example 7. When the resulting coating solution was allowed to stand at room temperature for 2 hours, precipitation of titanium dioxide was observed.

Tablets were coated using the coating liquids of Example 15 and Comparative Example 7, and coated tablets of Example 16 and Comparative Example 8 were prepared and their appearance and drop strength were compared.
The drop strength was determined by a test in which an acrylic tube having a diameter of 1.5 cm and a length of 100 cm was vertically installed on an iron plate having a thickness of 5 mm, and the coated tablet was dropped from the upper part of the cylinder onto the iron plate. The coated tablets of Example 16 and Comparative Example 8 were dropped 5 times each and the presence or absence of peeling of the film was visually observed.
Table 4 shows the prescription and coating conditions of the tablets used, and the coating amount and drop strength of the obtained coated tablets are shown below.

Tablet [Prescription] Compounding amount (% by weight)
(1) Reishi extract 20.0
(2) Reduced palatinose 50.0
(3) Cornstarch 29.0
(4) Magnesium stearate 1.0
[Production Method] Components 1 to 3 are mixed and granulated, then Component 4 is added and mixed, and then molded with a tableting machine to obtain tablets of 300 mg / tablet, diameter 9 mm, tablet thickness 4.5 mm.

Coating conditions (1) Coating pan: 15cm in diameter
(2) Amount of tablets: 50g
(3) Coating method: Spray (4) Pan rotation speed: 50 rpm
(5) Blower temperature: 60 ° C

In the coated tablet of Comparative Example 8, the white coating with titanium dioxide was weak and the base color was exposed. In the drop test, peeling of the film was observed. On the other hand, the coated tablet of Example 16 was uniformly coated with white, and no film peeling was observed in the drop test.

As described above, the coating liquid according to the present invention does not cause precipitation of titanium dioxide as in the comparative example even when allowed to stand, and can produce a uniformly colored coating with high film strength.

Claims (4)

In an edible coating liquid containing 3 to 25% by weight reduced palatinose, 0.1 to 20% by weight hydroxypropylcellulose, 0.1 to 10% by weight titanium dioxide, and water-containing ethanol having a water content of 5 to 30% by weight An edible coating liquid in which reduced palatinose is dispersed as solid particles. The edible coating solution according to claim 1, wherein the reduced palatinose is 3 to 20 % by weight and the hydroxypropyl cellulose is 1 to 16% by weight. A coated product coated with the edible coating solution according to claim 1. In an edible coating liquid containing 3 to 25% by weight reduced palatinose, 0.1 to 20% by weight hydroxypropylcellulose, 0.1 to 10% by weight titanium dioxide, and water-containing ethanol having a water content of 5 to 30% by weight A method for producing an edible coating liquid, wherein reduced palatinose is dispersed as solid particles.