Water-soluble film for chemical agent packaging and chemical agent packaging capsule

Abstract

Provided is a water-soluble film for chemical agent packaging, which, even when a chemical agent is housed in a packaging capsule formed of the water-soluble film and is stored for a long period of time, is capable of sufficiently reducing yellowing that occurs in the water-soluble film. This water-soluble film for chemical agent packaging is characterized by comprising: a water-soluble polyvinyl alcohol-based resin including an anion group-modified polyvinyl alcohol-based resin; a plasticizer; and an aldehyde scavenger. The aldehyde scavenger is preferably a urea derivative or a guanidine-based compound having an amino group.

Description

Water-soluble film for drug packaging and drug packaging capsules

[0001] The present invention relates to a water-soluble film for packaging medicines such as agricultural chemicals and detergents, and to a medicine-packaging capsule.

[0002] As a water-soluble film for packaging chemicals such as pesticides and detergents, a water-soluble film formed from a water-soluble polyvinyl alcohol resin containing an anionic group-modified polyvinyl alcohol resin is used, taking into consideration the solubility of the water-soluble film and its formability into packaging capsules. A predetermined amount of chemical can be stored in the packaging capsule obtained by forming the water-soluble film, and by placing the packaging capsule containing the chemical in a predetermined amount of water, the water-soluble film dissolves, yielding an aqueous solution of the chemical at a predetermined concentration.

[0003] Such a water-soluble film is obtained by forming a water-soluble polyvinyl alcohol-based resin containing an anionic group-modified polyvinyl alcohol-based resin, and in the film-forming process, the resin and / or the water-soluble film are heated. To prevent yellowing due to oxidation of the resin and / or the water-soluble film during this heating, a water-soluble polyvinyl alcohol-based resin containing an antioxidant, such as a triazole-based compound (see Patent Document 1 below) or a sulfite (see Patent Document 2 below), is used for film formation.

[0004] JP 2001-19819 A JP 2005-179390 A

[0005] The water-soluble polyvinyl alcohol resin containing the antioxidant described above can prevent yellowing during film formation, thereby obtaining a transparent water-soluble film. However, according to the inventors' studies, even if the water-soluble film produced has sufficient transparency, yellowing can occur in the water-soluble film when a drug is stored in a packaging capsule obtained by molding the water-soluble film and the capsule is stored for a long period of time. When yellowing occurs in the water-soluble film forming the packaging capsule, the appearance of the packaging capsule is impaired, and the drug contained therein appears to be deteriorated. Yellowing during storage of packaging capsules containing detergents containing oxygen-based bleaching agents such as sodium percarbonate as a drug has been significantly observed.

[0006] The present invention aims to provide a water-soluble film for packaging medicines and a medicine-packaging capsule that can sufficiently reduce yellowing that occurs in the water-soluble film even when medicines are stored in the packaging capsule formed from the water-soluble film for a long period of time.

[0007] The water-soluble film for packaging medicines that can achieve the above-mentioned object is characterized by containing a water-soluble polyvinyl alcohol-based resin including an anionic group-modified polyvinyl alcohol-based resin, a plasticizer, and an aldehyde scavenger.

[0008] The aldehyde scavenger is preferably a guanidine compound or a urea derivative having an amino group.

[0009] The amount of the aldehyde scavenger is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the water-soluble polyvinyl alcohol resin.

[0010] The anionic group-modified polyvinyl alcohol resin is preferably a maleic acid-modified polyvinyl alcohol resin, and the degree of modification is preferably 0.5 to 4.0 mol %.

[0011] The plasticizer preferably includes one or more selected from glycerin, sorbitol, polyethylene glycol, and diglycerin.

[0012] The water-soluble film preferably contains a sulfite as an antioxidant.

[0013] A drug-packaged capsule that can achieve the object of the present invention is a capsule that is formed from the above-mentioned water-soluble drug packaging film and contains a drug.

[0014] Compared to a water-soluble film that does not contain an aldehyde scavenger, the water-soluble film for packaging medicines according to the present invention can sufficiently reduce yellowing of the packaging capsules even when medicines are stored in the packaging capsules formed from the water-soluble film, and the appearance of the packaging capsules is not impaired, and the medicines stored do not appear to have deteriorated.

[0015] 1 is a graph showing that the yellowing of the water-soluble film forming the drug packaging capsule according to the present invention can be reduced compared to conventional water-soluble films.

[0016] The water-soluble film for pharmaceutical packaging according to the present invention (hereinafter simply referred to as the water-soluble film) contains a water-soluble polyvinyl alcohol resin including an anionic group-modified polyvinyl alcohol resin. The anionic group-modified polyvinyl alcohol resin contained in the water-soluble polyvinyl alcohol resin is not particularly limited, but examples include maleic acid-modified polyvinyl alcohol resin, itaconic acid-modified polyvinyl alcohol resin, acrylic acid-modified polyvinyl alcohol resin, methacrylic acid-modified polyvinyl alcohol resin, and 2-acrylamido-2-methylpropanesulfonic acid-modified polyvinyl alcohol resin. In this anionic group-modified polyvinyl alcohol resin, the ratio (modification degree) of the number of moles of monomers reacted for modification to the number of moles of all monomers constituting the anionic group-modified polyvinyl alcohol resin is preferably 0.5 to 4.0 mol%, more preferably 0.5 to 2.0 mol%. When the modification degree of the anionic group-modified polyvinyl alcohol resin is less than 0.5 mol%, the solubility in water tends to decrease, while when it exceeds 4.0 mol%, the productivity of the anionic group-modified polyvinyl alcohol resin tends to decrease. In particular, an anionic group-modified polyvinyl alcohol resin is preferably one in which the modified species is maleic acid-modified and the degree of modification is 0.5 to 4.0 mol %, since this improves the solubility of the drug packaging capsule in water.

[0017] The anionic group-modified polyvinyl alcohol resin used in the present invention may have repeating units of the following monomers to the extent that the effects of the present invention are not impaired. Examples of such monomers include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, and α-octadecene; complete alkyl esters of unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, and itaconic acid; nitriles such as acrylonitrile and methacrylonitrile; amides such as acrylamide and methacrylamide; alkyl vinyl ethers; N-acrylamidomethyltrimethylammonium chloride, allyltrimethylammonium chloride, dimethyldiallylammonium chloride, dimethylallyl vinyl ketone, N-vinylpyrrolidone, vinyl chloride, vinylidene chloride, polyoxyethylene (meth)allyl ether, polyoxypropylene (meth)allyl ether, and the like. polyoxyalkylene (meth)allyl ethers such as polyoxyethylene (meth)acrylate and polyoxypropylene (meth)acrylate; polyoxyalkylene (meth)acrylamides such as polyoxyethylene (meth)acrylamide and polyoxypropylene (meth)acrylamide; polyoxyethylene (1-(meth)acrylamide-1,1-dimethylpropyl) ester; polyoxyethylene vinyl ether; polyoxypropylene vinyl ether; polyoxyethylene allylamine; polyoxypropylene allylamine; polyoxyethylene vinylamine; polyoxypropylene vinylamine; and diacrylacetonamide.

[0018] Further examples include cationic group-containing monomers such as N-acrylamidomethyltrimethylammonium chloride, N-acrylamidoethyltrimethylammonium chloride, N-acrylamidopropyltrimethylammonium chloride, 2-acryloxyethyltrimethylammonium chloride, 2-methacryloxyethyltrimethylammonium chloride, 2-hydroxy-3-methacryloyloxypropyltrimethylammonium chloride, allyltrimethylammonium chloride, methallyltrimethylammonium chloride, 3-butenetrimethylammonium chloride, dimethyldiallylammonium chloride, and diethyldiallylammonium chloride.

[0019] Anionic group-modified polyvinyl alcohol resins are obtained by polymerizing a polymer by a known method, such as solution polymerization, bulk polymerization, or suspension polymerization, and then saponifying the polymer. Saponification is carried out using an alkali or acid, with alkali being particularly preferred. The degree of saponification is not particularly limited, but a range of 86 to 100 mol% is preferred because it makes it easier to adjust the solubility in water, with 87 to 99 mol% being more preferred, and 88 to 94 mol% being even more preferred. If the degree of saponification is less than 86 mol%, the water solubility of the anionic group-modified polyvinyl alcohol resin tends to decrease. The degree of saponification is measured in accordance with JIS K6726 (1994).

[0020] The degree of polymerization of the anionic group-modified polyvinyl alcohol resin is not particularly limited, but is preferably 700 or more, more preferably 900 or more, and even more preferably 1200 or more. If the degree of polymerization is less than 700, the mechanical properties of the water-soluble film and the pressure resistance of the final packaging capsule tend to decrease. The upper limit of the degree of polymerization is preferably 2500, more preferably 2200 or less, and even more preferably 1700 or less. If the degree of polymerization exceeds 2500, the water solubility of the water-soluble film tends to decrease.

[0021] The viscosity of a 4% by mass aqueous solution of the anionic group-modified polyvinyl alcohol resin at 20°C is not particularly limited, but is preferably 7.0 to 55 mPa s, more preferably 9.0 to 50 mPa s, and even more preferably 12 to 35 mPa s. The viscosity of the 4% by mass aqueous solution is measured in accordance with JIS K6726 (1994).

[0022] The water-soluble polyvinyl alcohol resin forming the water-soluble film of the present invention may be a mixture of anionic group-modified polyvinyl alcohol resins. In this case, anionic group-modified polyvinyl alcohol resins that differ in at least one of molecular weight, degree of polymerization, viscosity of a 4% by mass aqueous solution, degree of saponification, degree of modification, modified species, etc. may be used. Note that, as long as the object of the present invention is not impaired, other modified polyvinyl alcohol resins and / or unmodified polyvinyl alcohol resins may be contained as necessary.

[0023] The water-soluble film of the present invention contains a plasticizer to ensure moldability and prevent embrittlement of the film. The plasticizer preferably contains one or more selected from glycerin, sorbitol, polyethylene glycol, and diglycerin. Sorbitol is a sugar alcohol with a melting point of 80°C or higher. Furthermore, polyethylene glycol preferably has a weight-average molecular weight (hereinafter simply referred to as average molecular weight) of 106 or more, more preferably 150 to 400, and particularly preferably 200. Polyethylene glycols with an average molecular weight of less than 106 tend to volatilize easily from the water-soluble film, while those with an average molecular weight of more than 400 tend to have reduced compatibility with water-soluble polyvinyl alcohol-based resins containing an anionic group-modified polyvinyl alcohol-based resin. The content of the plasticizer is preferably 5 to 50 parts by mass, more preferably 8 to 40 parts by mass, and even more preferably 10 to 35 parts by mass, per 100 parts by mass of the water-soluble polyvinyl alcohol-based resin. If the amount of plasticizer is less than 5 parts by mass, the flexibility of the water-soluble film will be insufficient and the processability will be reduced, whereas if the amount of plasticizer is more than 50 parts by mass, the plasticizer will bleed out and the film will be prone to becoming sticky.

[0024] In addition to the plasticizers described above, the water-soluble film of the present invention may contain, within the scope of the object of the present invention, commonly used plasticizers, for example, polyhydric alcohols such as diethylene glycol, trimethylolpropane, triethylene glycol, dipropylene glycol, propylene glycol, 2-methyl-1,3-propanediol, and polyglycerin, polyethers such as polypropylene glycol, phenol derivatives such as bisphenol A and bisphenol S, sugar alcohols such as mannitol, xylitol, and pentaerythritol, amide compounds such as N-methylpyrrolidone, and compounds in which ethylene oxide is added to polyhydric alcohols such as pentaerythritol and sorbitol. These may be used alone or in combination of two or more.

[0025] The water-soluble polyvinyl alcohol resin forming the water-soluble film of the present invention preferably contains an antioxidant to prevent yellowing due to oxidation caused by heating during the film formation process. The antioxidant is preferably a sulfite, specifically an alkali metal salt of sulfite (e.g., sodium sulfite, potassium sulfite, etc.), preferably sodium sulfite. The sulfite content is preferably 0.1 to 1.9 parts by mass, more preferably 0.3 to 1.5 parts by mass, and even more preferably 0.3 to 1.1 parts by mass, per 100 parts by mass of the water-soluble polyvinyl alcohol resin. A sulfite content within this range can prevent yellowing due to heating during film formation or molding, and can also prevent precipitation of sulfite during storage of the formed water-soluble film.

[0026] The water-soluble film according to the present invention contains an aldehyde scavenger that captures aldehyde components generated during the decomposition of a water-soluble polyvinyl alcohol-based resin. Any aldehyde scavenger can be used as long as it has the ability to capture aldehyde components generated during the decomposition of a water-soluble polyvinyl alcohol-based resin and is compatible with the water-soluble polyvinyl alcohol-based resin. Examples of aldehyde scavengers include compounds having an amino group that reacts with aldehyde components, specifically guanidine compounds or urea derivatives having an amino group. Particularly preferred are aminoguanidine hydrochloride, semicarbazide hydrochloride, Aircleans FC-HA010D (trade name; an aqueous solution containing 16±1% by mass of a guanidine compound, an inorganic salt, and malic acid, ≦0.3% by mass of a nonionic surfactant (penetrating agent), and a pH adjuster) manufactured by Union Chemical Co., Ltd., and Chemcatch H6000HS and Chemcatch P9600 (both trade names; aldehyde catcher agents containing an amino group-containing compound as an active ingredient) manufactured by Otsuka Chemical Co., Ltd. The content of the aldehyde scavenger is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the water-soluble polyvinyl alcohol-based resin. If the content of the aldehyde scavenger is less than 0.01 part by mass, the aldehyde component generated by decomposition of the water-soluble polyvinyl alcohol-based resin tends to be insufficiently captured. On the other hand, if the content of the aldehyde scavenger exceeds 5 parts by mass, the aldehyde scavenger tends to precipitate on the surface of the water-soluble film.

[0027] Thus, compared with capsules formed from a water-soluble film containing an aldehyde scavenger, yellowing of the water-soluble film and capsules can be significantly reduced when a drug is stored in the capsules, compared with capsules formed from a water-soluble film without an aldehyde scavenger. The cause of this is presumed to be as follows: Water-soluble polyvinyl alcohol resins undergo degradation and yellowing in a two-stage manner. In the first stage, hydroxyl groups are oxidized to carbonyl groups. In the second stage, the carbonyl-initiated dehydration generates conjugated double bonds, which leads to the elongation of the conjugated system and / or the carbonyl-initiated cleavage of the main chain generates aldol condensation between lower aldehydes, followed by dehydration, oxidation, and the accumulation of unsaturated carboxylic acids such as crotonic acid, which are yellow substances. Thus, the formation of conjugated double bonds due to dehydration initiated by carbonyls and the resulting elongation of the conjugated system, combined with the accumulation of yellow substances due to scission of the main chain initiated by carbonyls, results in yellowing of water-soluble films containing water-soluble polyvinyl alcohol resins. The first stage of oxidation can be prevented by antioxidants such as sulfites contained in the water-soluble polyvinyl alcohol resins. However, the antioxidants exert their antioxidant effect during heating and other processes during film formation, significantly reducing their amount. Therefore, it is believed that the antioxidants are unable to exert sufficient antioxidant effect during storage of capsules containing pharmaceuticals. Furthermore, the second stage of formation of conjugated double bonds and the resulting elongation of the conjugated system is a dehydration reaction, while the scission of the main chain initiated by carbonyls is a retro-aldol reaction. Therefore, it is believed that antioxidants cannot suppress yellowing. In particular, the second stage is likely to progress in capsules containing detergents containing oxygen-based bleaching agents such as sodium percarbonate, which easily causes yellowing of the water-soluble films forming the capsules.

[0028] In this regard, by including an aldehyde scavenger having an amino group in the water-soluble film forming the packaging capsule, the aldehyde or lower aldehyde produced in the second stage reacts with the amino group of the aldehyde scavenger to produce imine, thereby suppressing aldol condensation between aldehyde components, thereby suppressing the production of unsaturated carboxylic acids, which are yellow substances, and thereby suppressing yellowing of the water-soluble film containing the water-soluble polyvinyl alcohol-based resin.

[0029] The water-soluble film of the present invention may contain other additives within a range that does not impair the physical properties of the water-soluble film. Examples of other additives include surfactants, water-soluble polymers, and additives. Examples of surfactants include nonionic surfactants, anionic surfactants, cationic surfactants, and zwitterionic surfactants. Among these, preferred surfactants are polyoxyethylene lauryl ether acetate sodium salt, polyoxyethylene alkyl ether phosphate potassium salt, di-2-ethylhexyl sulfosuccinate sodium salt, and polyoxyethylene alkyl ether sulfate sodium salt. These surfactants may be used alone or in combination. The content of the surfactant is preferably 0.03 to 1.00 parts by mass, more preferably 0.1 to 0.7 parts by mass, and even more preferably 0.2 to 0.4 parts by mass, per 100 parts by mass of the water-soluble polyvinyl alcohol resin. The surfactant can impart releasability from the cast surface during production of the water-soluble film, and can also facilitate processing such as sealing (water sealing, heat sealing) when producing pharmaceuticals, particularly liquid detergent packaging capsules, powder detergent packaging capsules, or packaging capsules containing powder detergent and liquid detergent.

[0030] Examples of water-soluble polymers include sodium polyacrylate, polyethylene oxide, polyvinylpyrrolidone, dextrin, chitosan, chitin, methylcellulose, hydroxyethyl cellulose, etc. Examples of additives include various fillers such as silica, aluminosilicate (zeolite), titanium oxide, talc, starch, and crosslinked acrylic fine particles, colorants, fragrances, extenders, antifoaming agents, release agents, ultraviolet absorbers, rust inhibitors, liquid paraffins, fluorescent brighteners, chelating agents, bittering agents such as denatonium benzoate, fatty acid substances, and inorganic powders.

[0031] The method for producing a water-soluble film for packaging medicines of the present invention includes a step of preparing an aqueous solution and a film-forming step of producing a water-soluble film.

[0032] The method for preparing the aqueous solution is not particularly limited, but examples include dissolving a water-soluble polyvinyl alcohol resin and additives such as a plasticizer, surfactant, and filler in a dissolution tank, or kneading a water-soluble polyvinyl alcohol resin in a hydrous state with additives such as a plasticizer, surfactant, and filler using a twin-screw extruder. The method for producing a water-soluble film containing a water-soluble polyvinyl alcohol resin is not particularly limited, but for example, a method can be used in which an aqueous solution or aqueous solvent solution of a water-soluble film composition containing a water-soluble polyvinyl alcohol resin is supplied to the surface of a rotating metal roll or other support member (including a metal belt surface) using a known device, and then peeled from the surface of the metal roll or other support member (including a metal belt surface) and wound up while drying. Known methods such as solution casting (casting) and roll coating can be used as this supply method. Furthermore, if necessary, the water-soluble film may be embossed, for example, matte embossed, by heating and pressing it between two rollers having embossed irregularities on the surface to form an embossed pattern.

[0033] The moisture content of the water-soluble film of the present invention obtained by film formation is preferably 4.0 to 9.0% by mass, more preferably 4.5 to 8.0% by mass, and even more preferably 5.0 to 7.5% by mass, under an environment of normal temperature, normal pressure, and normal humidity. If the moisture content is less than 4.0% by mass, the flexibility of the water-soluble film tends to decrease, and if the moisture content exceeds 9.0% by mass, the water-soluble film tends to adhere to itself.

[0034] The thickness of the water-soluble film for medicinal packaging of the present invention obtained by film formation is preferably 20 to 120 μm, more preferably 50 to 110 μm, and even more preferably 60 to 90 μm. Water-soluble films with a thickness of less than 20 μm tend to have insufficient tensile strength for use in medicinal packaging capsules, while water-soluble films with a thickness of more than 120 μm tend to have reduced moldability when formed into medicinal packaging capsules.

[0035] The obtained water-soluble film for medicinal packaging may be formed from only one layer, or may be formed by laminating two or more layers of the same or different water-soluble films having the same composition as the water-soluble film. A capsule package using such a water-soluble film is formed by bonding the edges of at least two sheets of water-soluble film together, and contains a medicinal product such as a detergent. Furthermore, the medicinal packaging capsule is produced by filling and sealing the contents with heat sealing or water sealing. The medicinal packaging capsule is preferably formed by a thermoforming method or a vertical-form-fill-seal (VFFS) method, and more preferably formed by a thermoforming method.

[0036] The packaging capsules formed with the water-soluble film for packaging medicinal products of the present invention are suitable for storing powder detergent as the medicinal product. They may also store powder detergent and liquid detergent and / or gel detergent. They may also be single-packaged, multi-chamber detergent packaging capsules that store a single powder detergent or liquid detergent, or two or more separate powder detergents and liquid detergents. They may also be pesticide packaging capsules that store pesticides as the medicinal product. In particular, the water-soluble film of the present invention is useful for packaging medicinal products containing oxygen bleaches such as sodium percarbonate, preferably powder detergents containing oxygen bleaches such as sodium percarbonate.

[0037] Examples of the present invention will be described in detail below, but the scope of the present invention is not limited to these examples.

[0038] (Water-soluble film composition) (1) The following materials were used for the water-soluble film composition. Water-soluble polyvinyl alcohol (PVA) resins A-1: ​​maleic acid-modified polyvinyl alcohol resin Degree of polymerization: 1700, degree of saponification: 88 mol%, degree of modification: 1.9 mol%, 4% by mass aqueous solution viscosity at 20°C: 28 mPa·s A-2: maleic acid-modified polyvinyl alcohol resin Degree of polymerization: 1000, degree of saponification: 88 mol%, degree of modification: 1.9 mol%, 4% by mass aqueous solution viscosity at 20°C: 10.5 mPa·s Plasticizers B-1: glycerin B-2: diglycerin B-3: polyethylene glycol (PEG: average molecular weight 200) B-4: sorbitol Antioxidant C-1: sodium sulfite Surfactant D-1: polyoxyethylene alkyl ether phosphate potassium salt Aldehyde scavenger E-1: aminoguanidine hydrochloride E-2: Semicarbazide hydrochloride E-3: Aircleans FC-HA010D (trade name, manufactured by Union Chemical Co., Ltd.) [16±1 mass% as solid content] (2) Water-soluble film compositions The PVA resin, plasticizer, antioxidant, surfactant, aldehyde scavenger, and water shown in Table 1 were added and kneaded to prepare the water-soluble film compositions of Examples 1 to 10 and Comparative Example 1. E-3 was added so that the solid content would be the parts by mass shown in Table 1.

[0039]

[0040] (Film Formation) The water-soluble film composition shown in Table 1 was formed into a film. The viscosity of this composition was measured at 85°C using a Brookfield viscometer and found to be approximately 3,000 mPa·s. A metal roll was prepared as a casting surface, and its surface was cleaned by wiping with a cloth moistened with pure water. The water-soluble film composition was cast onto the metal roll while heating the surface temperature of the metal roll to approximately 80 to 95°C. The metal roll was dried for 8 minutes while rotating, producing a water-soluble film for packaging capsules with a thickness of 75 μm. The moisture content of the resulting water-soluble film was measured in accordance with JIS K 6726 3.4, and the obtained volatile content value was measured as the moisture content.

[0041] (Yellowing Evaluation Test) The obtained water-soluble film was cut into a size of 165 mm x 75 mm, and the long side was folded in half so that the surface that would come into contact with the metal roll during casting would be on the outside. The two opposite sides were heat-sealed using a heat sealer (FS-315, manufactured by Fuji Impulse) to prepare a flat bag of 82 mm x 75 mm. 25 g of powder detergent ("finish" (registered trademark) Power & Pure Powder (trade name), manufactured by Reckitt Benckiser, pH: 10.6) was placed into the flat bag, and the remaining side was heat-sealed to produce a packaged capsule containing the powder detergent. The packaged capsule containing the powder detergent was then placed in a PET 15 μm / PE 50 μm laminated bag, sealed, and stored in an accelerated environment of 40°C and 20% RH for 14 days. After storage, the heat-sealed portion of the packaging capsule was cut off, the detergent was removed, and the detergent adhering to the film was wiped off. The yellowness index (YI value) of the water-soluble film was then measured using a spectrophotometer (SD 7000, manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS Z8722 (2009). The results are shown in Table 2 below. Table 2 also lists the moisture content (measured in accordance with JIS K 6726 3.4) and initial YI value of the water-soluble film obtained by film formation.

[0042]

[0043] As is clear from Table 2 and Figure 1, Examples 1 to 10, which contained an aldehyde scavenger, all had reduced YI values ​​after 14 days of storage compared to Comparative Example 1, which did not contain an aldehyde scavenger. Examples 1 to 6 and 10, which used both an antioxidant and an aldehyde scavenger, had even lower YI values ​​after 14 days of storage compared to Example 7, which contained only an aldehyde scavenger. In particular, the water-soluble film forming the packaging capsules of Example 5 had a YI value of less than 1.0 after 14 days of storage, and the water-soluble film was not perceived as yellowish to the naked eye and was sufficiently colorless and transparent. On the other hand, Examples 8 and 9, which did not contain an antioxidant but used multiple types of plasticizers, had even lower YI values ​​after 14 days of storage compared to Examples 1 to 4, 6, and 10, which contained an antioxidant.

[0044] The water-soluble film for packaging medicinal substances according to the present invention can be used for packaging capsules for packaging and storing medicinal substances such as agricultural chemicals and detergents.

Claims

1. A water-soluble polyvinyl alcohol-based film for pharmaceutical packaging, characterized by containing a water-soluble polyvinyl alcohol-based resin containing an anion group-modified polyvinyl alcohol-based resin, a plasticizer, and an aldehyde scavenger.

2. The water-soluble polyvinyl alcohol-based film for pharmaceutical packaging according to claim 1, wherein the aldehyde scavenger is a guanidine-based compound or a urea derivative having an amino group.

3. The water-soluble polyvinyl alcohol-based film for pharmaceutical packaging according to claim 1, wherein the aldehyde scavenger is 0.01 to 5 parts by mass with respect to 100 parts by mass of the water-soluble polyvinyl alcohol-based resin.

4. The water-soluble polyvinyl alcohol-based film for pharmaceutical packaging according to claim 1, wherein the anion group-modified polyvinyl alcohol-based resin is a maleic acid-modified polyvinyl alcohol resin, and the degree of modification is 0.5 to 4.0 mol%.

5. The water-soluble polyvinyl alcohol-based film for pharmaceutical packaging according to claim 1, wherein the plasticizer contains one or more selected from glycerin, sorbitol, polyethylene glycol, and diglycerin.

6. The water-soluble polyvinyl alcohol-based film for pharmaceutical packaging according to claim 1, wherein the water-soluble film contains a sulfite as an antioxidant.

7. A pharmaceutical packaging capsule, characterized in that a drug is stored in a packaging capsule formed of the water-soluble polyvinyl alcohol-based film for pharmaceutical packaging according to claim 1.

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