RU2530093C1 - Method of producing monocrystals of serotonin salts by crystallisation from aqueous solutions - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method includes dissolving a starting salt in water and obtaining a saturated salt solution at 25±3°C, heating the solution to 40-50°C and adding not more than 50% of the starting salt dissolved at 25±3°C, cooling to 4±2°C and then to -18±2°C until the solution completely freezes, then thawing at room temperature of 25±3°C to form monocrystals of the starting serotonin salt and separating the mother solution by decantation. The starting salt used is serotonin adipate or serotonin creatinine sulphate monohydrate. The method enables to obtain transparent lamellar crystals of serotonin adipate with average size of 0.15×0.12×0.05 mm (±0.02 mm in each plane), serotonin creatinine sulphate monohydrate with average size of 0.30×0.20×0.08 mm without serotonin degradation features.

EFFECT: enabling the investigation of the internal structure and conformational features of serotonin in a solid phase.

3 cl, 2 tbl, 2 ex

Description

The invention relates to the pharmaceutical and food industries, in particular to the production of biologically active substances that can be used as biologically active additives. More specifically, an improved method for producing single crystals of serotonin salts by crystallization from aqueous solutions.

The neurotransmitter serotonin is involved in various physiological aspects of human and animal life. Serotonin is a stimulant of smooth muscle, peristalsis and secretory activity of the gastrointestinal tract; increases capillary stability, is involved in the regulation of the sleep - wake cycle and other significant processes [Mohammad-Zadeh L.F., Moses L., Gwaltney-Brant S.M. Serotonin: a review. // Journal of veterinary pharmacology and therapeutics. 2008. Vol.31, No. 3. P.187-199., Berger M., Gray J. a. Roth B.L. The expanded biology of serotonin. // Annual review of medicine. 2009. Vol.60. P.355-366]. It is reliably known that the level of the content of neurotransmitters in general and serotonin in particular largely determines the behavioral capabilities of an animal or person, its mood, tone, and social behavior (McGuire, MT, Troishi A., 1998. Darwinian psychiatry. New York: Oxford University Press , JH Tumer, Handbook of Social theory // Springer, 2000, 745p.), Which was first shown on primates (RD Masters, MT McGuire, The Neurotransmitter Revolution: Serotonin, Social Behavior, and the Law // Southern Illinois University, 1994 , 285p.). Such extensive and various properties of serotonin in the human body are usually associated with its conformational features, which allows serotonin to efficiently bind to receptors responsible for various functions [Akhrem A. et al. Theoretical Investigation of the Conformational Mobility of the serotonin molecule and several of its analogs // Theoretical and Experimental Chemistry. 1978. Vol.13, No. 5. P.682-686.]. The study of conformations in various salts of serotonin is most efficiently carried out in the crystalline state by the method of single crystal diffraction.

According to the latest version of the Cambridge Structural Data Bank (February 2013), crystals have been grown to date and the internal structure of only three salts of serotonin (serotonin oxalate, serotonin creatinine sulfate monohydrate, picotrate serotonin monohydrate) has been deciphered. The authors noted difficulties when using traditional techniques for crystallization of serotonin salts. The fourth structure (serotonin adipate) was deciphered by us using a crystal grown by the proposed method.

When decoding the structure of serotonin oxalate, a crystal was used from the commercial powder preparation Sigma Co., St. Louis, and the attempt to crystallize from methanol was unsuccessful - the crystals quickly degraded in air [Aniy A. et al. The Crystal Structure of Serotonin Hydrogen Oxalate // Acta Chem. Scand. A. 1978. Vol. 32, No. 3. P.267-270].

To obtain crystals of serotonin creatinine sulfate monohydrate and picotrate of serotonin monohydrate, the technique of slow cooling of an aqueous solution was used, which led to a change in the color of the crystal of serotonin creatinine sulfate and was noted by the authors [Thewalt U., Bugg C.E. The crystal and molecular structure of serotonin picrate monohydrate // Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry. International Union of Crystallography, 1972. Vol. 28, No. 1. P.82-92, Karle I. L., Dragonette K.S., Brenner S. a. The crystal and molecular structure of the serotonin-creatinine sulphate complex // Acta Crystallographica. International Union of Crystallography, 1965. Vol.19, No. 5. P.713-716].

A common drawback of these methods is the significant degradation of serotonin salts, which is diagnosed by a color change. Chemical degradation of biologically active amines (including serotonin) is a common problem for this class of compounds and occurs due to the prolonged presence in the liquid phase during crystallization.

The objective of the invention is to create a method for producing single crystals of serotonin salts from aqueous solutions, the technical result of which is to obtain single crystals of serotonin salts of the correct form without signs of degradation, allowing the study of the internal structure and conformational features of serotonin in the solid phase

The problem is solved by creating a method in which a salt solution is saturated at a temperature of 25 ± 3 ° C, then the solution is heated to a temperature of 40-50 ° C and no more than 50% of the amount of the initial salt dissolved at 25 ± 3 ° C is added, after which sequential cooling is carried out to 4 ± 2 ° C, then to -18 ± 2 ° C until the solution is completely frozen, then thawed at room temperature (25 ± 3 ° C) to form single crystals of the initial serotonin salt, the mother liquor is separated by decantation.

Serotonin adipate and serotonin creatinine sulfate monohydrate were used as the starting salt.

Example 1. In 3-4 ml of distilled water at 25 ± 3 ° C, a weighed portion of serotonin adipate was dissolved to obtain a saturated solution. Thus, 5 samples were prepared, which were then heated to 35, 40, 45, 50 55 ° C, adding no more than 50% of the amount of serotonin adipate from the dissolved at 25 ± 3 ° C. The solutions were successively cooled at room temperature (25 ± 3 ° C) for several minutes, then in the refrigerator (+ 4 ± 2 ° C), then in the freezer (-18 ± 2 ° C) until the solution was completely frozen. The solutions were thawed at room temperature (25 ± 3 ° C), the mother liquor was separated from the precipitate by decantation immediately after defrosting. On the bottom and walls of the vessel, even crystals of regular shape were observed without signs of degradation of serotonin in serotonin adipate (transparent color). Serotonin adipate crystals were plates with an average size of 0.15 × 0.12 × 0.05 mm (± 0.02 mm in each plane).

Adding more than 50% of the amount of serotonin adipate from dissolved at 25 ± 3 ° C leads to rapid degradation of serotonin in the liquid phase, it is impossible to obtain crystals without signs of degradation.

The obtained crystals were used in diffraction experiments and the internal structure of the crystalline serotonin adipate was first established, the conformational features of the serotonin molecule in this adipic salt in the solid phase were determined in comparison with the known serotonin salts.

Crystalline products were investigated by x-ray diffraction analysis (Oxford Diffraction Gemini R Ultra difractometer, Mo Kα radiation). Decryption and analysis of the data was carried out using the following programs: CrysAlis PRO; SHELXS97, SHELXL97, Olex2 vl. 2. Mercury 3.0, Platon and CrystalExplorer.

The results of varying the temperature range when heating a solution of serotonin adipate are shown in table 1.

Table 1 Heating temperature Crystal color Quantity and quality assessment of crystal sizes Result 35 ° C Transparent Many, the average size does not exceed 0.10 × 0.08 × 0.03 mm (± 0.01 mm in each plane) - 40 ° C Transparent Small, average size 0.15 × 0.12 × 0.05 mm (± 0.02 mm in each plane) + 45 ° C Transparent Small, average size 0.15 × 0.12 × 0.05 mm (± 0.02 mm in each plane) + 50 ° C Transparent Small, average size 0.15 × 0.12 × 0.05 mm (± 0.02 mm in each plane) + 55 ° C Brown Small, average size 0.15 × 0.12 × 0.05 mm (± 0.02 mm in each plane) -

Example 2. A sample of serotonin creatinine sulfate monohydrate was dissolved in 3-4 ml of distilled water at 25 ± 3 ° C until a saturated solution was obtained. Thus, 5 samples were prepared, which were then heated to 35, 40, 45, 50 55 ° C, adding serotonin creatinine sulfate monohydrate in an amount of not more than 50% of the original salt dissolved at 25 ± 3 ° C. The solutions were successively cooled at room temperature (25 ± 3 ° C) for several minutes, then in a refrigerator (4 ± 2 ° C), then in a freezer (-18 ± 2 ° C) until the solution was completely frozen. The solutions were thawed at room temperature (25 ± 3 ° C), the mother liquor was separated from the solid phase by decantation immediately after defrosting. On the bottom and walls of the vessel, even crystals of regular shape were observed without signs of degradation of serotonin in serotonin creatinine sulfate monohydrate (transparent color). Crystals of serotonin creatinine sulfate monohydrate were plates with an average size of 0.30 × 0.20 × 0.08 mm.

Adding more than 50% of the amount of serotonin creatinine sulfate monohydrate from dissolved at 25 ± 3 ° C leads to rapid degradation of serotonin in the liquid phase, it is impossible to obtain crystals without signs of degradation.

Based on the obtained crystals, diffraction experiments were carried out, the internal structure of crystalline serotonin creatinine sulfate monohydrate was established, the conformational features of the serotonin molecule in the complex of creatinine sulfate monohydrate in the solid phase were determined.

Crystalline products were investigated by x-ray diffraction analysis (Oxford Diffraction Gemini R Ultra diffractometer, Mo Kα radiation). Decryption and analysis of the data was carried out using the following programs: CrysAlis PRO; SHELXS97, SHELXL97, Olex2 vl. 2, Mercury 3.0, Platon and CrystalExplorer.

The results of varying the temperature range when heating the solution are shown in table 2.

table 2 Heating temperature Crystal color Quantity and quality assessment of crystal sizes Result 35 ° C Transparent Many, the average size does not exceed 0.15 × 0.12 × 0.05 mm (± 0.01 mm in each plane) - 40 ° C Transparent Small, average size 0.30 × 0.20 × 0.08 mm (± 0.02 mm in each plane) + 45 ° C Transparent Small, average size 0.30 × 0.20 × 0.08 mm (± 0.02 mm in each plane) + 50 ° C Transparent Small, average size 0.30 × 0.20 × 0.08 mm (± 0.02 mm in each plane) + 55 ° C Brown Small, average size 0.30 × 0.20 × 0.08 mm (± 0.02 mm in each plane) -

Claims (3)

1. A method of producing single crystals of serotonin salts from an aqueous solution, comprising dissolving the initial salt in water, characterized in that the salt solution is saturated at a temperature of 25 ± 3 ° C, then the solution is heated to a temperature of 40-50 ° C and no more than 50% is added from the amount of the initial salt dissolved at 25 ± 3 ° C, after which sequential cooling is carried out to 4 ± 2 ° C, then to -18 ± 2 ° C until the solution is completely frozen, then thawed at room temperature 25 ± 3 ° C with the formation of single crystals initial salt of serotonin, uterine growth op is separated by decantation. 2. The method according to claim 1, characterized in that the serotonin adipate is used as the starting salt. 3. The method according to claim 1, characterized in that as the starting salt, serotonin creatinine sulfate monohydrate is used.