Soft capsule coating and soft capsule

Abstract

To provide a soft capsule coating that has flexibility and resilience without containing glycerol, and a soft capsule having the soft capsule coating.SOLUTION: A soft capsule coating contains gelatin and sodium salt of 3-hydroxybutyric acid but is free of glycerol. The proportion of sodium salt of 3-hydroxybutyric acid may be 35 pts.wt. or more and 55 pts.wt. or less relative to 100 pts.wt. of gelatin. The soft capsule coating is filled with contents, forming a soft capsule.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a soft capsule film and a soft capsule provided with the soft capsule film.

Background Art

[0002] Flexibility and elasticity are required for the soft capsule film. This is mainly because the content encapsulated in the soft capsule film is usually a "liquid" (solution or suspension), and the volume change due to the temperature change of the environment is large. When the soft capsule film lacks flexibility and elasticity, cracks may occur in the soft capsule film due to the volume change of the content, and the content may leak out. Therefore, a plasticizer is generally added to the soft capsule film to enhance flexibility and elasticity, and glycerin has been widely used as the plasticizer.

[0003] On the other hand, the present applicant has proposed a technology that can impart flexibility and elasticity to the soft capsule film without using glycerin (see Patent Documents 1 and 2).

[0004] The technology of Patent Document 1 is a soft capsule film having gelatin as a film base, containing highly saccharified reduced starch syrup and erythritol without containing glycerin. The technology of Patent Document 2 is a soft capsule film having gelatin as a film base, containing monoacetylmonoacylglycerol without containing glycerin.

[0005] The present applicant has continuously searched for a new plasticizer that can impart flexibility and elasticity to the soft capsule film in place of glycerin. The present invention has been made in that process.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] As described above, the present invention aims to provide a soft capsule coating that is flexible and elastic without containing glycerin, and a soft capsule equipped with said soft capsule coating. [Means for solving the problem]

[0008] To solve the above problems, the soft capsule coating according to the present invention is It contains gelatin and the sodium salt of 3-hydroxybutyric acid, but does not contain glycerin.

[0009] In this invention, the soft capsule shell, which uses gelatin as a film base, contains the sodium salt of 3-hydroxybutyric acid (β-hydroxybutyric acid) without containing glycerin. 3-hydroxybutyric acid is a substance represented by the molecular formula C4H8O3 or CH3CHOHCH2COOH, and is produced in the human body when glucose concentration is insufficient, by the breakdown of fat in the liver as an alternative energy source. In recent years, 3-hydroxybutyric acid has also been artificially produced by fermenting sugars from natural food materials. Due to the presence of a chiral carbon atom, D-type and L-type optical isomers exist.

[0010] In the process of searching for a novel plasticizer that could replace glycerin, the applicant focused on the high hygroscopicity and low volatility of 3-hydroxybutyric acid and considered whether it could act as a plasticizer. As a result of the investigation described in detail below, it was found that the sodium salt of 3-hydroxybutyric acid can be used as a plasticizer to replace glycerin, leading to the present invention.

[0011] Therefore, by incorporating 3-hydroxybutyric acid into a soft capsule coating using gelatin as the coating base, it is possible to provide a soft capsule coating that is flexible and elastic without containing glycerin.

[0012] The soft capsule coating according to the present invention has the above configuration, The product may contain "35 to 55 parts by weight of sodium 3-hydroxybutyric acid per 100 parts by weight of gelatin."

[0013] By setting the ratio of sodium 3-hydroxybutyric acid to gelatin within the above range, as will be described in detail later, it is possible to provide a soft capsule coating that is excellent in film formation, flexibility, and elasticity, without containing glycerin.

[0014] Next, the soft capsule according to the present invention is "The contents are filled into the soft capsule shell described above."

[0015] The "contents" can include any pharmaceutical ingredients, herbal ingredients, health food ingredients, or nutritional supplements without any particular limitations. These ingredients (the substance to be ingested) can be dissolved or suspended in oil or a fat or oily substance, or the substance itself can be in the form of an oil or paste.

[0016] This configuration makes it possible to provide a soft capsule having a flexible and elastic soft capsule coating.

[0017] Furthermore, 3-hydroxybutyric acid is said to have effects that suppress oxidation reactions and inflammatory reactions, in addition to its function as an energy source that can replace glucose. Therefore, it is possible to provide soft capsules in which the capsule shell itself, which is filled with ingredients that contribute to human health, such as pharmaceutical ingredients and nutritional supplements, contains the sodium salt of 3-hydroxybutyric acid, which is a health-beneficial ingredient. [Effects of the Invention]

[0018] As described above, according to the present invention, it is possible to provide a soft capsule film having flexibility and elasticity without containing glycerin, and a soft capsule provided with the soft capsule film.

Embodiment for Carrying Out the Invention

[0019] Hereinafter, a soft capsule film which is an embodiment of the present invention, and a soft capsule provided with the soft capsule film will be described.

[0020] The soft capsule film of the present embodiment contains gelatin and a sodium salt of 3-hydroxybutyric acid (hereinafter sometimes abbreviated as "3HB"), and does not contain glycerin.

[0021] A soft capsule provided with such a soft capsule film can be produced using a rotary die type forming device, and includes a film stock solution preparation step of preparing a film stock solution of the soft capsule film, a forming / filling step of filling and encapsulating the contents into the soft capsule film simultaneously with the formation of the soft capsule film, and a drying step of drying the soft capsule after the forming / filling step.

[0022] In the film stock solution preparation step, gelatin which is a film base is dissolved in water while heating, and a sodium salt (powder) of 3HB is added thereto and heated and dissolved, and then well stirred and mixed to prepare a film stock solution.

[0023] The forming / filling step is performed using a rotary die type forming device. A rotary die type forming device generally mainly includes a casting drum for forming a film stock solution into a film shape, a pair of die rolls having a forming mold formed on the outer surface, a wedge-shaped segment disposed between the die rolls, and a pump for pressing the contents into the segment and extruding the contents from the tip of the segment.

[0024] In the molding and filling process, the film concentrate is first poured onto the surface of the casting drum and gelled to form a film. Next, two of the formed films are fed between a pair of die rolls along the segments. As the pair of die rolls rotate in opposite directions, the two films are heat-sealed to form a capsule with an open space at the top, into which the contents extruded from the segments are filled. Simultaneously, the two films are heat-sealed at the top, forming a soft capsule with the contents filled into a closed internal space. Soft capsules molded in a rotary die molding machine have seams, which are the marks left by the heat seals.

[0025] In the drying process, the soft capsule coating is dried in a humidity-controlled dryer until it reaches a predetermined moisture content.

[0026] Next, we will explain the research that led to the inclusion of 3HB sodium salt as a substitute for glycerin in the soft capsule coating, which uses gelatin as the coating base.

[0027] Using gelatin as the film-forming base, film-forming stock solutions for samples S1 to S4 were prepared by containing a 40% by mass aqueous solution of 3HB, sodium salt of 3HB (3HB content 81.8% by mass), magnesium salt of 3HB (3HB content 89.6% by mass), and calcium salt of 3HB (3HB content 83.8% by mass), respectively. For the 40% by mass aqueous solution of 3HB, sodium salt of 3HB (powder), magnesium salt of HB (powder), and calcium salt of 3HB (powder), the D-type 3HB and its salt "OKETOA®" manufactured by Osaka Gas Chemical Co., Ltd. were used.

[0028] The proportions of these 3HB compounds and their salts relative to 100 parts by weight of gelatin were set to 40 parts by weight in terms of 3HB equivalent. This was determined by referring to the fact that the composition of a typical soft capsule coating, which uses gelatin as the coating base and glycerin as the plasticizer, is 40 parts by weight of glycerin per 100 parts by weight of gelatin.

[0029] In contrast, the sodium salt of 3HB is formed by substituting one hydrogen atom in the -COOH group of each molecule of 3HB with sodium, whereas the magnesium salt and calcium salt of 3HB are formed by substituting one hydrogen atom in the -COOH group of each of two molecules of 3HB with one atom of magnesium or calcium.

[0030] The undiluted coating solutions of samples S1 to S4 were each cast onto a smooth surface, and their film-forming properties and flexibility / elasticity after drying were evaluated as follows. Hereafter, the soft capsule coating may be simply referred to as "the coating."

[0031] <Film-forming properties> When the undried coating was peeled off the smooth surface of the casting target, if the coating could be peeled off in a sheet and stretched without breaking when pulled by hand, it was evaluated as a "○" indicating that a coating with appropriate strength was formed well. If the coating could not be peeled off in a sheet or broke when pulled, it was evaluated as a "×" indicating poor coating formation.

[0032] <Flexibility and elasticity> After drying the sheet-like coating until its moisture content reached 8% by mass, the coating was folded in half. If no cracks or fissures were observed with the naked eye, it was evaluated as having good flexibility and elasticity ("○"). If even slight cracks or fissures were observed, it was evaluated as having poor flexibility and elasticity ("×"). In cases where the coating formation was poor, the evaluation of flexibility and elasticity was not performed.

[0033] Table 1 shows the evaluation results for film formation and flexibility / elasticity after drying for each film obtained from samples S1 to S4, along with the composition of the film concentrate.

[0034] [Table 1]

[0035] When using a 40% by mass aqueous solution of 3HB for sample S1, no film was formed on the film-forming stock solution, suggesting that the film-forming ability inherent in gelatin was impaired. This was thought to be due to the low pH of the 40% by mass aqueous solution of 3HB affecting the film-forming ability of gelatin.

[0036] Furthermore, regarding the samples using 3HB salts, sample S2, which used the sodium salt, showed good film formation and flexibility / elasticity after drying. However, samples S3 and S4, which used the magnesium salt and calcium salt respectively, showed good film formation but poor flexibility / elasticity after drying. This was thought to be because the sodium salt of 3HB has higher solubility in water and superior hygroscopicity (moisture retention) compared to the magnesium and calcium salts of 3HB, allowing the soft capsule film to retain moisture more easily, and the retained moisture enhances the flexibility and elasticity of the film.

[0037] From the results above, it was found that the sodium salt of 3HB acts as a plasticizer that imparts flexibility and elasticity to the soft capsule coating with gelatin as the coating base. Therefore, the desirable ratio of sodium salt of 3HB to gelatin was investigated. Specifically, the coating solutions of samples S11 to S19, each with a different ratio of sodium salt of 3HB to 100 parts by weight of gelatin, were cast onto a smooth surface in the same manner as above, and the film-forming ability and the flexibility and elasticity after drying were evaluated using the same method as above. The results, along with the composition of the coating solutions, are shown in Table 2.

[0038] [Table 2]

[0039] As shown in Table 2, the film-forming solutions of samples S12 to S16, in which the ratio of sodium 3HB to 100 parts by weight of gelatin was 35 parts by weight or more and 55 parts by weight or less, showed good film-forming properties, and the flexibility and elasticity of the film after drying were also good. In contrast, the film-forming solutions of samples S17 to S19, in which the ratio of sodium 3HB to 100 parts by weight of gelatin was 30 parts by weight or less, showed good film-forming properties, but the flexibility and elasticity of the film after drying were poor, suggesting that there was insufficient sodium 3HB as a plasticizer. On the other hand, the film-forming solution of sample S11, in which the ratio of sodium 3HB to 100 parts by weight of gelatin was 60 parts by weight, showed poor film-forming properties, suggesting that too much sodium 3HB inhibits the film-forming ability of gelatin.

[0040] For sample S15, which exhibits good film-forming properties and good flexibility and elasticity after drying, the non-adhesion (difficulty in adhering) and disintegration properties of the dried soft capsule film were confirmed using the following method. For comparison, the same evaluation was performed on sample R, a conventional film stock solution using gelatin as the film base and glycerin as the plasticizer.

[0041] <Non-adherent> After casting the undiluted coating solution onto a smooth surface to form a film, the film was dried in the same manner as described above and cut into 1cm x 1cm sheet pieces. Fifty of these sheet pieces were placed in a standard No. 9 glass bottle and stored for 100 hours under three different conditions. After 100 hours, when the sheet pieces were removed from the bottle, if there was no adhesion between the sheet pieces and each piece was completely separated, it was evaluated as having very good non-adhesion ("◎"). If some sheet pieces were adhered but could be easily peeled off by hand, it was evaluated as having good non-adhesion ("○"). If any adhesion occurred that could not be peeled off by hand, even if only partially, it was evaluated as having poor non-adhesion ("×").

[0042] The three types of preservation conditions are as follows: • Room temperature environment (normal storage conditions) Condition A: Temperature 40°C, relative humidity 75% (more severe conditions than normal storage conditions) Condition B: Temperature 50°C (even more severe conditions than Condition A)

[0043] <Collapse-like> 0.5 grams of the dried sheet-like coating was immersed in 100 grams of water maintained at 37°C. If the coating completely disintegrated within 20 minutes, it was evaluated as having good disintegration properties ("○"). If the coating remained intact after 20 minutes, it was evaluated as having poor disintegration properties ("×"). The evaluation results, along with the composition of the undiluted coating solution, are shown in Table 3.

[0044] [Table 3]

[0045] As shown in Table 3, the soft capsule coating using the sodium salt of 3HB as a plasticizer exhibited non-adhesion properties comparable to those of conventional soft capsule coatings using glycerin as a plasticizer, and also showed excellent disintegration properties similar to those of conventional soft capsule coatings using glycerin as a plasticizer.

[0046] As described above, by incorporating 3HB sodium salt as a plasticizer into a soft capsule coating using gelatin as the coating base, without including glycerin, we were able to create a soft capsule coating with good flexibility and elasticity. In particular, by setting the proportion of 3HB sodium salt to 35 parts by weight or more and 55 parts by weight or less per 100 parts by weight of gelatin, good coating formation was achieved, as well as excellent flexibility and elasticity of the soft capsule coating. Furthermore, the non-adhesion of the soft capsule coatings to each other and their disintegration in water at a temperature similar to body temperature were comparable to those of conventional soft capsule coatings containing glycerin as a plasticizer, indicating that 3HB sodium salt can be used as a novel plasticizer to replace glycerin.

[0047] In addition, 3HB is said to have effects that suppress oxidation reactions and inflammatory reactions, as well as acting as an energy source that can replace glucose. Normally, soft capsules are filled with ingredients that contribute to human health, such as pharmaceutical ingredients or nutritional supplements, within a soft capsule shell. However, the soft capsule with the soft capsule shell of this embodiment is a novel soft capsule in which not only the contents but also the soft capsule shell itself contains ingredients that contribute to health.

[0048] Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various improvements and design changes are possible without departing from the spirit of the present invention, as shown below.

[0049] For example, other additives such as colorants and fragrances can be added to the soft capsule coating produced by the present invention.

Claims

1. It contains gelatin and the sodium salt of 3-hydroxybutyric acid, but does not contain glycerin. A soft capsule coating characterized by the following features.

2. The product contains 35 to 55 parts by weight of sodium salt of 3-hydroxybutyric acid per 100 parts by weight of gelatin. The soft capsule coating according to feature 1.

3. The soft capsule coating according to claim 1 or claim 2 is filled with contents. A soft capsule characterized by the following features.

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