Vitamin B group compound composition and its production

Abstract: A composition which consists essentially of a compound belonging to the Vitamin B group and having a solubility in water of not more than 5% and mannitol, is stable in itself and undergoes less influence under ambient humidity conditions. Its good flowability is retained during storage, only with very small changes, if any.

Description: This invention relates to a vitamin B group compound composition which has good stability and flowability and can advantageously be used in the food, pharmaceutical and feed industries, among others, in the manufacture of such dosage forms as powders, fine granules, capsules, pills, tablets and pellets. BACKGROUND OF THE INVENTION Vitamin B group compounds, such as folic acid and vitamin B₂, are incorporated in various food, pharmaceutical, feed and other compositions generally at low addition levels. Therefore, it is particularly required that such compounds be distributed uniformly in said compositions. In particular, the levels of addition of folic acid and vitamin B₂ are low in most instances. However, since they occur as fine crystalline powders having a high specific volume and showing a strong tendency toward aggregation, their flowability and handling properties are poor and unsatisfactory. Therefore, for preparing homogeneous compositions, a preliminary dilution step is generally employed in which they are diluted 10-, 100- or 1,000-fold, for instance, with starch, alpha-starch, lactose or some other appropriate excipient. A method of obtaining free-flowing powders that has already been provided comprises contacting with a spray jet of a superfine absorbent powder and effecting spray drying (Japanese Patent Application KOKAI No. 49-7415). However, the superfine absorbent to be used is an inorganic material unsuited for pharmaceutical purposes. In addition, the method fails to give compositions containing folic acid or vitamin B₂ in high concentrations. Another method that has been provided for preparing a vitamin B₂ composition capable of being directly submitted to tableting (Japanese Patent Application KOKAI No. 62-174013) gives granules on fluidized bed granulation using a macromolecular compound, such as water-soluble cellulose, as a binding agent. However, this method can hardly be applied to the manufacture of pharmaceutical preparations which should contain vitamin B₂ in very low concentrations, for instance. US-A-3 145 146 discloses the use of spray dried mannitol for pharmaceutical tablets containing e.g. vitamin B group compounds. In some of the prior art compositions, the proportion of the excipient is too high for incorporation of other active ingredients into the compositions, while in others the excipient itself is unsuited for pharmaceutical preparations. These are the problems that remain to be solved. Accordingly, the advent of a composition which contains a vitamin B group compound, such as folic acid or vitamin B₂, has a low excipient content, has good flowability but no tendency toward aggregation, and can be used in the manufacture of pharmaceutical preparations is desired. SUMMARY OF THE INVENTION The present inventors found that a vitamin B group compound composition which is safe, has good flowability and can be readily incorporated into various formulations can be obtained by uniformly suspending a vitamin B group compound in an aqueous solution of mannitol and subjecting the resulting suspension to spray drying. They further found that said composition can be converted to a more stable granular powder composition by coating the same with a wax, an oil or fat. The present invention has been completed based on these findings. DETAILED DESCRIPTION OF THE INVENTION The invention thus provides a composition which consists essentially of mannitol and a compound belonging to the vitamin B group and having a solubility in water of not more than 5%, wherein the content of the compound belonging to the vitamin B group is within the range of 100 to 5,000 parts by weight per 100 parts by weight of mannitol, and a method of producing such composition. Any commercially available grade of mannitol can be used in the practice of the invention. Since mannitol is listed in the Japanese Pharmacopeia, the composition according to the invention can be used for pharmaceutical purposes. The invention is applicable to the following vitamin B group compounds, among others: folic acid, vitamin B₂, riboflavin butyrate ester, biotin, thiamine mononitrate, dibenzoylthiamine, dibenzoylthiamine hydrochloride, thiamine acetylsulfate, thiamine laurylsulfate, thiamine naphthaline-2,6-disulfonate, thiamine naphthaline-1,5-disulfonate, pyridoxine-3,4'-dioctanoate, pyridoxine-3,4'-dipalmitate, pyridoxine-3,4'-dilaurate and pyridoxine-3,4'-dilaurate hydrochloride. These have a solubility in water at 20°C of not more than 5% (weight/volume), preferably not more than 3%, more preferably not more than 1%. The vitamin B group compound content in the composition according to the invention is generally within the range of 100 to 5,000 parts by weight, preferably 200 to 3,000 parts by weight, more preferably 400 to 2000 parts by weight per 100 parts by weight of mannitol. In cases where the content of the vitamin B group compound, such as folic acid or vitamin B₂, exceeds 5,000 parts by weight per 100 parts by weight of mannitol, the granular composition obtained may readily be disintegrated. Where the vitamin B group compound content is below 100 parts by weight per 100 parts by weight of mannitol, the high excipient (mannitol) content may lead to an excessively high mannitol proportion in final preparations manufactured by admixing the composition with another or other active ingredients. That large quantity of mannitol, which is voluminous, may cause troubles in preparing such compositions as tablets. The composition according to the invention can be produced, for example, in the following manner. An aqueous solution of mannitol is prepared by dissolving mannitol in distilled water. A vitamin B group compound is added to this solution and uniformly dispersed therein by means of a homomixer. The resulting suspension is then subjected to spray drying using a spray drier. Since the vitamin B group compound to be used in the practice of the invention has a solubility in water of not more than 5%, said compound remains in a suspended state in the aqueous solution of mannitol. The aqueous solution of mannitol to be used should have a mannitol concentration of not less than 0.5% (weight/volume). Said concentration should appropriately be selected depending on such factors as the kind and amount of the vitamin B group compound to be contained in the composition to be prepared. The composition obtained by spray drying generally occurs as a powder which is considerably uniform in composition. The drying is performed at a drying temperature within the range of about 100-180°C, preferably 130-160°C, while the disk is rotated at a rate within the range of about 1,000-30,000 rpm (revolutions per minute), preferably 5,000-20,000 rpm. The composition according to the invention may be coated with a wax, an oil or fat, which is used in an amount within the range of 0.1 to 50% by weight, preferably 5 to 30% by weight, based on said composition. As examples of the wax, fat or oil which are usable in the practice of the invention, there may be mentioned carnauba wax, paraffins, stearic acid, white beeswax, macrogols, glycerol fatty acid esters, and varius hardened fats and oils (cottonseed oil, soybean oil, palm oil, corn oil, sunflower oil, rapeseed oil, lard, beef tallow, etc.), among others. While it is a primary object of the invention to provide a composition which comprises a single vitamin B group compound and mannitol, the invention can also provide, in another aspect thereof, a composition which contains two or more vitamin B group compounds and mannitol. As compared with the conventional compositions in which lactose, starch or the like is used, the composition according to the invention is stable in itself and undergoes less influence under ambient humidity conditions. Therefore, its good flowability is retained during storage, only with very small changes, if any. Furthermore, the composition coated with a wax, a fat or oil exerts little influence on another or other active ingredients when it is admixed with these, whereby the stability of the resulting combination composition itself is improved as well. Since it is sufficient to use only a small amount of mannitol as an excipient in the composition according to the invention, such operations as weighing and mixing can be rationalized in the manufacture of tablets, capsules, powders, granules, pellets and other preparations. Furthermore, since the composition according to the invention is small and uniform in grain size, it can be used for low addition level incorporation of a vitamin B group compound or compounds. The invention is particularly effective in cases where folic acid or vitamin B₂ is used; there, the invention affords a composition having good handling characteristics that have never been attained in the prior art. The following examples illustrate the invention in further detail. The ingredient materials used all occurred as powders. The sieve mesh designations are based on the Japanese Industrial Standard definition (JIS K 6900). Example 1 [The powder composition consisting of folic acid and mannitol] Folic acid was obtained from Takeda Chemical Industries and mannitol from Imperial Chemical Industries (I.C.I.). Folic acid (95 g) was added to a solution of 5 g of mannitol in 200 ml of distilled water and homogeneously dispersed therein by means of a homomixer (T.K. homomixer model M, manufactured by Tokushu Kika Kogyo Comp.). This folic acid suspension was subjected to spray drying using a mobile minor type spray drier (Ashizawa-Niro Atomizer LTD.) while the homogeneity of said suspension was maintained by stirring. The drying temperature was 150°C and the disk was rotated at 20,000 rpm. The thus-obtained composition occurred as a yellow powder. Particle size distribution and repose angle of the composition. (1) Particle size distribution (2) Repose angle: 42°. Example 2 [The powder composition consisting of vitamin B₂ and mannitol] Vitamin B₂ was obtained from Hoffmann-La Roche Inc. and mannitol from I.C.I. Vitamin B₂ (90 g) was added to a solution of 10 g of mannitol in 200 ml of distilled water and homogeneously dispersed therein by means of a homomixer (T.K. homomixer model M, manufactured by Tokushu Kika Kogyo Comp.). This vitamin B₂ suspension was subjected to spray drying using a mobile minor type spray drier (Ashizawa-Niro Atomizer LTD.) while the homogeneity of the suspension was maintained by stirring. The drying temperature was 150°C and the disk was rotated at 20,000 rpm. The thus-obtained composition occurred as a yellow powder. Particle size distribution and repose angle of the composition. (1) Particle size distribution (2) Repose angle: 40°. Example 3 [Wax-coated powder composition consisting of folic acid and mannitol] The powdery composition consisting of folic acid and mannitol obtained in Example 1 was wax-coated by the hot hexane method. Carnauba wax was used as the wax. Thus, in a tightly closable container, 0.5 g of carnauba wax was dissolved in 100 ml of hexane warmed to about 75°C, and 10 g of the powder composition was added to the solution with stirring by means of a stirrer. The resultant mixture was then allowed to cool to room temperature with the container tightly closed. Thereafter the mixture was filtered through a filter paper. The residue on the filter paper was dried at 40°C under vacuum to give a wax-coated powder composition consisting of folic acid and mannitol. Example 4 [The powder composition consisting of folic acid and mannitol] Folic acid was obtained from Takeda Chemical Industries and mannitol from I.C.I. Folic acid (90 g) was added to a solution of 10 g mannitol in 200 ml of distilled water and homogeneously dispersed therein with a homomixer (T.K. homomixer model M, manufactured by Tokushu Kika Kogyo Comp.). This folic acid suspension was subjected to spray drying using a mobile minor type spray drier (Ashizawa-Niro Atomizer LTD.) while homogeneity of the suspension was maintained by stirring. The drying temperature was 150°C and the disk was rotated at 20,000 rpm. The thus-obtained dry composition occurred as a yellow powder. Particle size distribution and repose angle of the composition (1) Particle size distribution (2) Repose angle: 41°. Example 5 [The powder composition consisting of vitamin B₂ and mannitol] Vitamin B₂ was obtained from Hoffmann-La Roche Inc. and mannitol from I.C.I. Vitamin B₂ (97 g) was added to a solution of 3 g of mannitol in 200 ml of distilled water and homogeneously dispersed therein by means of a homomixer (T.K. homomixer model M, manufactured by Tokushu Kika Kogyo Comp.). This vitamin B₂ suspension was subjected to spray drying using a mobile minor type spray drier (Ashizawa-Niro Atomizer LTD.) while the homogeneity of the suspension was maintained by stirring. The drying temperature was 150°C and the disk was rotated at 20,000 rpm. The thus-obtained composition occurred as a yellow powder. Particle size distribution and repose angle of the composition. (1) Particle size distribution (2) Repose angle: 42.2°. Test method 1 [Folic acid assay] In the experimental examples, the folic acid assay procedure was performed using light-impermeable containers and avoiding direct sunlight. Assay preparations were prepared by extracting 50 mg of a sample with 20 ml of a dichloromethane-1 N aqueous ammonia mixture (1:1) and subjected to assay by the USP (U.S. Pharmacopeia) method (high-performance liquid chromatography). Test method 2 [Vitamin B₂ assay] In the experimental examples, the vitamin B₂ assay procedure was performed using light-impermeable containers and avoiding direct sunlight. Assay preparations were prepared by extracting 30 mg of a sample with 50 ml of 5 N acetic acid and subjected to assay by the USP method (colorimetry). Test method 3 [Flowability evaluation (measurement of repose angle)] In the experimental examples, the compositions containning folic acid or vitamin B₂ were evaluated for their flowability as follows: Fifty-five-gram portions of each sample composition were placed in amber-glass desiccators respectively conditioned to 11%, 20%, 31%, 43%, 53%, 68%, 75%, 82% and 91% and, after 2 weeks of storing at 40°C, repose angle measurements were performed using a Konishi model FK repose angle measuring apparatus (Konishi Medical & Surgical Co.). Experimental Example 1 [Stability and repose angle data for a folic acid composition and a vitamin B₂ composition] Contents: Expressed in terms of residual percentage. As is evident from the data given in the above table, the folic acid composition and vitamin B₂ composition obtained in Example 1 and Example 2, respectively, did not suffer any substantial flowability losses during 2 weeks of storage at 40°C under various humidity conditions ranging from the highest 91% relative humidity to the lowest 11% relative humidity. The compositions retained their respective active ingredient contents stably. Experimental Example 2 [Stability of folic acid in a premix] The wax-coated composition obtained in Example 3 was packed in the form of a premix into a glass bottle and stored airtightly therein under the conditions specified in the table given below, followed by folic acid assay and residual percentage calculation. As the data in the above table indicate, the wax-coated folic acid composition obtained by the method of the invention was more stable than the folic acid bulk substance used as a control. The premix used was prepared according to the following formula (folic acid content = 100 mg/kg of premix): Experimental Example 3 [Flowability of a folic acid composition and of a vitamin B₂ composition] The folic acid composition obtained in Example 4 and the vitamin B₂ composition obtained in Example 2 as well as folic acid compositions and vitamin B₂ compositions containing the conventional excipient lactose or corn starch were subjected to flowability and stability testing for investigating possible influences of the humidity during storage on the flowability and stability of each composition. Each composition was allowed to stand at 40°C for 2 weeks under the respective humidity conditions (11% to 91% relative humidity) specified in the two tables given below, followed by water content determinations and repose angle measurements. The compositions used for comparison were as follows: (Folic acid) 10 % Lactose: Lactose 10 g Folic acid 90 g 10 % Corn starch: Corn starch 10 g Folic acid 90 g (Vitamin B₂) 10 % Lactose: Lactose 10 g Vitamin B₂ 90 g 10 % Corn starch: Corn starch 10 g Vitamin B₂ 90 g The above compositions for comparison were prepared by the same spray drying method as used in Examples 1 to 3 and submitted to measurements. A 2-gram portion of the samples containing of folic acid stored at a temperature of 40°C for 2 weeks under the specified humidity conditions (11% to 91 % relative humidity) was assayed for water content by the Karl-Fischer method and the increase or decrease in water content was calculated relative to the initial value. A 0.5-gram portion of the samples containing of vitamin B₂ stored at a temperature of 40°C for 2 weeks under the specified humidity conditions (11% to 91% relative humidity) was heated at a temperature of 105° for 2 to 3 hours, and the increase or decrease in water content was calculated relative to the initial value. The repose angle measurement was performed with a 100-gram portion each of the samples stored at a temperature of 40°C for 2 weeks under the specified humidity conditions (11% to 91% relative humidity) using a Konishi model FK angle-of-repose measuring apparatus (Konishi Medical & Surgical Co.). The samples were further evaluated for their flowability by the eye. The measurement and evaluation results were expressed in terms of (+),(-) and (±). Repose angle: (-) for 40-45°C, (±) for 45-50°, (+) for > 50°. Each data in the parentheses (lower row): Increase or decrease in water content relative to the initial vale. Repose angle: (-) for 40-45°C, (±) for 45-50°, (+) for > 50°. Each data in the parentheses (lower row): Increase or decrease in water content relative to the initial vale. The data shown in the above two tables have revealed that the compositions according to the invention in which mannitol is used show higher stability and less flowability losses during storage as compared with the compositions in which lactose or corn starch, each a conventional excipient, is used.

Claims: A composition which consists essentially of mannitol and a compound belonging to the vitamin B group and having a solubility in water of not more than 5%, wherein the content of the compound belonging to the vitamin B group is within the range of 100 to 5,000 parts by weight per 100 parts by weight of mannitol. A composition as claimed in Claim 1, wherein the compound belonging to the vitamin B group has a solubility in water of not more than 3%. A composition as claimed in Claim 1, wherein the compound belonging to the vitamin B group has a solubility in water of not more than 1%. A composition as claimed in any of Claims 1 to 3, wherein the compound belonging to the vitamin B group and having a solubility in water of not more than 5% is folic acid or vitamin B₂. A composition as claimed in any of Claims 1 to 4, said composition being in the form of a powder. A composition as claimed in any of Claims 1 to 5, wherein the content of the compound belonging to the vitamin B group is within the range of 200 to 3,000 parts by weight per 100 parts by weight of mannitol. A composition as claimed in any of Claims 1 to 5, wherein the content of the compound belonging to the vitamin B group is within the range of 400 to 2,000 parts by weight per 100 parts by weight of mannitol. A composition as claimed in any of Claims 1 to 7, as obtained by suspending, in an aqueous solution of mannitol, the compound belonging to the vitamin B group and subjecting the resulting suspension to spray drying. A composition as claimed in claim 8, wherein the compound belonging to the vitamin B group is folic acid or vitamin B₂. A method of producing a composition according to any of Claims 1 to 9, which comprises suspending, in an aqueous solution of mannitol, the compound belonging to the vitamin B group, and subjecting the resulting suspension to spray drying. A method as claimed in Claim 10, wherein the compound belonging to the vitamin B group is folic acid or vitamin B₂. A composition as claimed in any of Claims 1 to 9, said composition being coated with a wax, an oil or fat. A composition as claimed in Claim 12, wherein the wax is carnauba wax. A composition as claimed in Claim 12 or 13, wherein a wax, an oil or fat is used in an amount within the range of 0.1 to 50% by weight based on said composition. A composition as claimed in Claim 12 or 13, wherein a wax, an oil or fat is used in an amount within the range of 5 to 30% by weight based on said composition.

Inventors: IZUHARA SEIJI, KAKIGUCHI YOSHITOMI, YOKOTA KUNIHIKO, IZUHARA, SEIJI, KAKIGUCHI, YOSHITOMI, YOKOTA, KUNIHIKO
Applicants: TAKEDA CHEMICAL INDUSTRIES LTD, TAKEDA CHEMICAL INDUSTRIES, LTD.
Application year: 1990
Main classification: A61K9
IPC codes: A61K9, A23K1, A61K31, A61K47, A61P3