SOLVENT SYSTEM TO BE ENCLOSED IN CAPSULES

Abstract: To increase the solubility of acidic medicines, a high concentration solvent system to be encapsulated comprises a) 10-80 % by weight acidic medicine, b) 0.1-1.0 mole hydroxide ions for one mole equivalent of said medicine, and c) 1-20 % by weight water included in polyoxyethylene sorbitan fatty acid ester as the solvent.

Description: SOLVENT SYSTEM TO BE ENCLOSED IN CAPSULES BACKGROUND OF THE INVENTION In general, it is preferable that medicines are easy to swallow and in the administrational form of small volume or quantity. In addition, it is desirable that their ingredients are uniformly distributed and they are administered efficiently, e.g., in a high concentration. Encapsulation can satisfy such purposes as discussed in a Japanese patent application titled "Simplified Encapsulation of Medicines," which has been published in the Japanese Unexamined Patent Gazette No. 1-502185. This Gazette discloses a specific solvent solution system that is to be encapsulated and composed of an ionizable medicine, hydroxide ions or hydrogen ions enough to enhance the solubility of said medicine, and a specified amount of water and polyethylene glycol (PEG). However, this solvent system using PEG can cause a local reaction due to existing hydroxide ions depending on the properties of other components in the capsule. As the result, an ester may be produced and, thereby, may cause the purity of the encapsulated contents to be lowered. The inventors of the present invention have earnestly investigated the purity deterioration of the solute component (medicine) due to its reaction with the solvent and found that polyoxyethylene sorbitan fatty acid ester (hereaf er, abbreviated POSE) is a solvent useful for preventing the deterioration of purity, and have reached the present invention. Field of the Invention The present invention relates to a solvent system that includes a highly concentrated acidic medicine, the solubility of which is enhanced by partial ionization of said medicine. This solvent system is used by being enclosed in soft gels (soft elastic gelatin capsules) or hard gelatin shells. Outline of the Invention The present invention relates to a high concentration solvent system to be enclosed in capsules, said system being composed of a) 10-80% by weight acidic medicine, b) 0.1-1.0 mole hydroxide ions for one mole of said medicine, and c) 1-20% by weight water included in POSE, the mean molecular weight of said POSE being 600-3000. SUMMARY OF THE INVENTION Hereafter, the present invention will be explained in detail. a) Ibuprof en, Naproxen, Indomethacin, Acetaminophen, etc. may be exemplified as among the acidic medicines to be used in this invention. Said acidic medicine is selectively used in the range of about 10- 80% by weight for the amount of POSE in consideration of the kind of acidic medicine used. The use of the medicine in the region under or over said range is less advantageous because the system may become too low in concentration in the former while it may become inhomogeneous, causing the crystallization of the acidic medicine in the form of insoluble substances in the latter. b) In the present invention, about 0.1-1.0 mole hydroxide ions is used for each molar equivalent of said acidic medicine. Hydroxide ions originated, for example, from sodium and/or potassium hydroxide, are used together with water. Use of hydroxide ions in the concentration under or over the above-mentioned range is less advantageous because the acidic medicine may not be dissolved in the former, causing an inhomogeneous phase system and, on the other hand, the gelatin constituting the shell of capsules tends to be hydrolyzed in the latter, causing leaking capsules. c) in the present invention, about 1-20% by weight water is included in POSE. If the water content is lower than about 1% by weight, the ionization of the acidic medicine might be incomplete though it depends on the nature of the medicine used, making the desired solubility unattainable. On the other hand, if the water content is more than about 20% by weight, the capsule containing such water may be softened and impractical. In the present invention, this water can be added directly to the POSE or the acidic medicine; otherwise it can be added to the hydroxide to be used in order to obtain an aqueous solution of alkaline hydroxide, which is afterwards added to the POSE. In the present invention, POSEs with mean molecular weights of approximately 600-3000 are preferably used. Such POSEs are well known, for example, under the trade name of Tween (Atlas Powder Co.) and are easily available in the market. Specific POSEs useful in the present invention include: TWEEN 20 ethylene oxide condensate of sorbitanmonolaurate TWEEN 21 ethylene oxide condensate of sorbitanmonolaurate TWEEN 40 ethylene oxide condensate of sorbitanmonopalmitate TWEEN 60 ethylene oxide condensate of sorbitanmonostearate TWEEN 61 ethylene oxide condensate of sorbitanmonostearate TWEEN 65 ethylene oxide condensate of sorbitantristearate TWEEN 80 ethylene oxide condensate of sorbitanmonooleate TWEEN 81 ethylene oxide condensate of sorbitanmonooleate TWEEN 85 ethylene oxide condensate of sorbitantrioleate Effects of the Invention The effects of the present invention may be listed as follows: a) The solubility of acidic medicine can be increased by about 4- 400%. b) The chemical stability of the included medicine is higher than that in the case where PEG is used as the primary solvent. c) When filled in capsules, the capsule contents can be reduced in volume. d) No deteriorative effects are inflicted on the shell of capsules. DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments will be described with emphasis laid on the contrast with PEG so as to explain the present invention in further detail. Example l 10 g each of Ibuprofen and Naproxen, both acidic medicines, was partially neutralized with a potassium hydroxide solution in PEG 400 and polyoxyethylene sorbitan fatty acid easter ("polysorbate" in Japanese Pharmacopeia; trade name: TWEEN) and the solubilities of these medicines were measured. It is possible as shown in Table 1 to increase the solubility of the medicine. Table l Example 2 Ibuprofen in various polyoxyethylene sorbitan fatty acid ester solutions (TWEEN) was partially neutralized with an alkaline solution and preserved 105°C or 44 hours. The amount of ester produced between the acidic medici and the solvent and the content of the remaining Ibuprofen were measured an compared with those in the case where PEG is used instead of POSE. It is shown in Table 2 that the formation rate of ester can be made low than that in the case where PEG is used as solvent. Ta le 2 After Treated . . . Value determined after preserved at 105°C for 44 hours ND: Not Detected Example 3 Naproxen in various polyoxyethylene sorbitan fatty acid ester solutio was partially neutralized with an alkaline solution and preserved at 105°C f 44 hours. The amount of ester produced between the acidic medicine and t solvent and the content of the remaining Naproxen were measured to compared with those in the case where PEG is used. It is shown in Table 3 that the formation rate of ester can be made low than that in the case where PEG is used as solvent. Table 3 After Treated . . . Value determined after preserved at 105°C for 44 hours ND: Not Detected S B Example 4 Ibuprofen dissolved separate in three kinds of solvents - - two kinds polyoxyethylene sorbitan fatty acid ester (TWEEN 20 and TWEEN 80) an polyethylene glycol - - was partially neutralized (0.3-0.4 m/e) with alkali solutions and the obtained solutions were encapsulated into soft capsules whos shell films are made of 100 parts gelatin, 35 parts glycerin and 15 parts sorbit using a rotary soft-capsule filling machine, producing each capsule whose fi weight is approximately 390mg. It was found in these capsules preserved at 40°C for 6 months that th formation rate of ester is lower in the capsules filled with POSE than in thos filled with PEG. Table 4 -6/1- Change in Ester Formation with Time (%) -7- Example 5 Naproxen separately dissolved in three kinds of solvents - - two kinds of POSE (TWEEN 20, TWEEN 80) and PEG - - was partially neutralized with alkaline solutions and the obtained solutions were encapsulated into soft capsules whose shell films are made of 100 parts gelatin, 30 parts glycerin and 15 parts sorbitol using a rotary soft-capsule filling machine, producing each capsule whose fill weight is approximately 574 mg. It was found in these capsules preserved for 4 months at 40°C that the formation rate of ester is lower in the capsules filled with POSE than those in PEG. Ta le 5

Claims: -8- WE CLAIM AS OUR INVENTION: 1. A high concentration solvent system to be enclosed in capsules, said solvent system comprising a) about 10-80% by weight of an acidic medicine, b) about 0.1-1.0 mole of hydroxide ions for each mole of said medicine, and c) about 1-20% by weight water dissolved in a solvent consisting essentially of a polyoxyethylene sorbitan fatty acid ester, the mean molecular weight of said polyoxyethylene sorbitan fatty acid ester being between about 600-3000. 2. The high concentration solvent system described in Claim 1, said acidic medicine being ibuprofen or naproxen. 3. The high concentration solvent system of Claim 1, said hydroxide ions originating from an aqueous solution of alkaline hydroxide. 4. A high concentration solvent system of ibuprofen comprising 30- 80% by weight ibuprofen, 0.1-1.0 mole hydroxide ions for one mole ibuprofen and 1-20% by weight water included in polyoxyethylene sorbitan fatty acid ester as the solvent and being suitably enclosed in soft capsules or hard capsules or tableted. 5. A high concentration solvent system of naproxen comprising 20- 80% by weight naproxen, 0.3-0.6 mole hydroxide ions for one mole naproxen and 1-15% by weight water included in polyoxyethylene sorbitan fatty acid ester as the solvent and said hydroxide ions originating from potassium hydroxide or sodium hydroxide.

Inventors: HAKAMADA ICHIRO, MAKINO HIROKAZU, YAMADA OSAMU, HAKAMADA, ICHIRO, MAKINO, HIROKAZU, YAMADA, OSAMU
Applicants: SCHERER CORP R P, R.P. SCHERER CORPORATION
Application year: 1992
Main classification: A61K9
IPC codes: A61K9, A61K31, A61K47, A61P29