JPS647983B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a stable aqueous solution of a compound having a thiol group. More particularly, the present invention relates to a process for preparing a stable aqueous solution of a compound having a thiol group selected from captopril, cysteine, glutathione and mercaptopropionylglycine, which comprises adding an amino acid or a salt thereof, gelatin or a dipeptide. Compounds having a thiol group are widely distributed in nature, such as animals, plants, and microorganisms. These compounds exert various remarkable physiological effects, such as in-vivo oxidation-reduction, detoxification, and cell activation, and are widely used in the treatment and prevention of diseases. Therefore, obtaining stable formulations of compounds having these thiol groups is a very important issue. However, compounds with thiol groups are extremely unstable in the presence of water, and as shown in the following,
It has the property of being easily self-oxidized. 4R-SH+O ₂ →2R-S-S-R+2H ₂ O This oxidation reaction is accelerated by the aging temperature, residual oxygen in the sealed container, etc. Therefore, in order to improve these drawbacks, various methods have been studied in the past. For example, a method of adding zinc ions to an aqueous cysteine solution [Pharmacy, 35 , 171-175 (1975)], a method of adding zinc sulfate to a glutathione solution [Pharmaceutical, 28 , 73-75]
(1968)], a method of adding ethylenediaminetetraacetic acid (EDTA) to an aqueous cysteine solution [Chemical
Chem.Pharm.Bull., 19 , 1006-1010.
(1971)], a method of adding polyhydric alcohols and soluble sulfites to an aqueous cysteine solution (Japanese Patent Publication No. 46
-31993), a method of adding lactams such as pyrrolidone and pyroglutamic acid as stabilizers to an aqueous solution of cysteine and glutathione (Japanese Patent Publication No. 46
-31994), proteins with thiol groups and cysteine, glutathione or thiamine are combined into vitamins.
A method for obtaining a mixed disulfide compound by reacting in the presence of a _B12 analog (Japanese Patent Publication No. 16321/1989), a method for reacting activated dextran treated with a cyanide halide or an organic cyanate ester with glutathione, and a composite obtained by reacting with glutathione. A method for stabilizing thiol compounds by allowing the body to coexist with thiol compounds (Japanese Patent Application Laid-Open No. 50-57979). A method for stabilizing a thiol compound by coexisting the complex with a thiol compound (Japanese Patent Application Laid-Open No. 51-100025
No.) etc. are known. Additionally, conventional methods using antioxidants, reducing agents (eg, sodium sulfite, sodium bisulfite, sodium thiosulfite, hydroquinone, hydrosulfite, etc.) are widely used. However, these methods do not necessarily produce the desired effects and have drawbacks when applied to pharmaceutical preparations. As a result of intensive research into the stabilization of compounds having a thiol group, the present inventors found that by adding an amino acid or its salt, gelatin, or dipeptide to an aqueous solution of the compound having a thiol group, the compound having a thiol group was stabilized. The present invention was completed based on this discovery. The compound having a thiol group used in the present invention is captopril.

【formula】 cysteine

[Formula] Glutathione or mercaptopropionylglycine

[Formula] can be mentioned. Amino acids used in the present invention include:
Neutral, acidic and basic amino acids are used without particular limitation. These amino acids include, for example, neutral amino acids such as glycine, alanine, serine, diencholic acid, aminobutyric acid, threonine,
Valine, norvaline, methionine, leucine, isoleucine, citrulline, phenylalanine, tyrosine, thyroxine, proline, oxyproline or tryptophan; acidic amino acids include aspartic acid or glutamic acid; basic amino acids include arginine, lysine, oxylysine,
Ornithine, canavanine or histidine can be mentioned. Of these amino acids,
Preferably glycine, serine, threonine, phenylalanine, aspartic acid, glutamic acid,
Arginine, lysine or histidine. Furthermore, as salts of amino acids, alkali metal salts such as sodium salts and potassium salts; mineral acid salts such as hydrochlorides and sulfates can be used without particular limitation. Additionally, gelatin or dipeptides can be used in the present invention. Examples of dipeptides include glycylglycine, glycylalanine or lysyllysine. Among these, gelatin or glycylglycine is preferred. In the present invention, the preferred pH range is usually 3.0 to
9.0, most preferably 5.0 to 6.0. Further, the amount of the amino acid or its salt, gelatin or dipeptide added in the present invention is effective even if it is small, but it is usually preferably 0.5 molar equivalent or more of the compound having a thiol group. The present invention will be explained in more detail below with reference to Examples and Test Examples, but the present invention is not limited thereto. Example 1 While blowing nitrogen gas into 900 ml of distilled water for injection, 2.0 g of captopril was dissolved, followed by 1.0 g of anhydrous citric acid and 3.2 g of arginine.
After adjusting the pH to 5.0 using an aqueous N-sodium hydroxide solution, the total amount was adjusted to 1. The solution prepared in this manner was dispensed into 2 ml white ampoules, and the space was then filled with nitrogen gas as required, followed by sealing to obtain an injection solution. Example 2 While blowing nitrogen gas into 900 ml of distilled water for injection, 1.12 g of cysteine was dissolved, followed by 1.0 g of anhydrous citric acid and 1.50 g of glycine. Thereafter, an injection solution was prepared in the same manner as in Example 1. Example 3 While blowing nitrogen gas into 900 ml of distilled water for injection, 28.3 g of glutathione was dissolved, followed by 2.0 g of sodium monohydrogen phosphate and 32.1 g of arginine.
was dissolved. After adjusting the pH to 6.0 using N-hydrochloric acid,
The total amount was set as 1. The solution prepared in this manner was dispensed into 2 ml white ampoules, and the space was then filled with nitrogen gas as required, followed by sealing to obtain an injection solution. Example 4 While blowing nitrogen gas into 900 ml of distilled water for injection, 1.70 g of mercaptopropionylglycine was dissolved, followed by 1.0 g of anhydrous citric acid and 3.2 g of arginine.
g and 7.5 g of sodium chloride were dissolved. below,
An injection solution was prepared in the same manner as in Example 1. Test Example 1 Stability of Compounds Having Thiol Groups Due to Addition of Amino Acids The injection solutions prepared in Examples 1 to 4 were kept at 100°C for 64 hours in a thermostatic water bath, and then dithiopyridine colorimetric method [RD Grassetti et al.; Arch.Biochem .
Biophys., 119 , 41 (1967)], the residual rate of the compound having a thiol group was measured. In addition, as a comparison, a sample without amino acid addition was prepared in the same way.
A similar test was conducted. In all of these samples, the ampoule space was replaced with nitrogen gas. The test results are shown first.

【table】

[Table] All the results showed that the addition of amino acids showed superior stability compared to the case without addition of amino acids. Test Example 2 Stability of captopril against the influence of temperature depending on the type of added amino acids In Example 1, the added amino acids were determined as shown in Table 2 below.
The reaction rate of captopril at each temperature was measured according to a conventional method using various amino acids shown in Table 1.
As a comparison, a sample without arginine was prepared in the same manner as in Example 1 and tested in the same manner. These samples were used as they were without replacing the ampoule space with nitrogen gas. The test results are shown in Table 2. In Table 2, smaller values indicate better stability.

[Table] The results showed superior stability when various amino acids were added compared to when no amino acids were added. Test Example 3 Stability of captopril against the influence of oxygen due to the addition of amino acids The injection solution prepared in Example 1 (captopril 2
mg/ml, citric acid 1mg/ml, arginine 3.2mg/
ml, PH=5.0) 0.45ml is sealed in a 2ml ampoule,
Next, oxygen was sealed in this. This sample was kept at 100°C for a certain period of time according to a conventional method, and the residual rate of captopril was measured. As a comparison, a sample without arginine was prepared in the same manner and tested in the same manner. The test results are shown in Table 3.

[Table] All of the results showed superior stability when arginine was added compared to when arginine was not added.

Claims (1)

[Claims] 1. A method for producing a stable aqueous solution of a compound having a thiol group selected from captopril, cysteine, glutathione and mercaptopropionylglycine, which comprises adding an amino acid or a salt thereof, gelatin or dipeptide.