Novel solid phases comprising metformin

Abstract

The present invention describes novel solid phases comprising metformin (MET) and a molecule having a hydroxyl, carboxyl or phenol group as co-formers, with improved pharmaceutical properties in comparison with metformin compounds already known in the prior art. In some embodiments of the present invention, the co-forming agents are selected from anticholesterolemic agents, antilipidemic agents and antioxidants. Preferably, the solid phases can be included in pharmaceutical compositions. Other embodiments of the invention describe the uses of the solid phases to manufacture a drug for treating or preventing metabolic syndrome and / or diabetes.

Description

[0001] NEW SOLID PHASES OF METFORMIN

[0002] FIELD OF INVENTION

[0003] The present invention relates to novel solid phases (NFS) of metformin, in particular to amorphous and crystalline solids thereof, and their use in the preparation of compositions for the treatment of type 2 diabetes mellitus, metabolic syndrome, and related diseases. More specifically, the present invention relates to novel solid phases comprising metformin and a coformer, with improved physicochemical and pharmacological properties.

[0004] BACKGROUND OF THE INVENTION

[0005] Metformin (MET) is an oral antidiabetic drug belonging to the biguanide group. Currently, MET is the first-line treatment for type 2 diabetes mellitus in most clinical guidelines and is used daily by more than 200 million patients.

[0006] Metformin reduces blood glucose levels, primarily by improving the sensitivity of the liver and peripheral tissues to insulin without affecting insulin secretion. Furthermore, it has been shown to have a protective effect against diabetes complications.

[0007] Metformin (MET) is commonly administered as the metformin hydrochloride salt (METHC1), which has the formula C4H11N5HC1 and a molecular weight of 165.6 g / mol. Its physicochemical properties include a melting point of 223–226°C and a log P of -2.6. METHC1 has high water solubility (484–496 mg / mL at 20°C) and low bioavailability (50%) after oral administration. While MET in its free base form is pharmaceutically useful, it is unstable.

[0008] Oral absorption of metformin (MET) is variable and incomplete, with an oral bioavailability of 50–60% under fasting conditions, and it is absorbed slowly. Peak plasma concentrations (Cmax) are reached between one and three hours after taking immediate-release metformin and between four and eight hours with extended-release formulations. Therefore, the bioavailability and plasma binding of metformin are poor.

[0009] In the present invention, the term novel solid phases (NSPs) refers to any solid material consisting of at least two molecular or ionic entities in any stoichiometric ratio, which may be salts, cocrystals, coamorphs, or solvates. It is understood that a phase has unique characteristics that define the compound.

[0010] Obtaining solid phases of pharmaceutical compounds represents a promising strategy for optimizing the physicochemical characteristics of active ingredients without altering their chemical structure. Composed of an active ingredient and a coformer linked by intermolecular forces such as hydrogen bonds, Van der Waals forces, or nn bonds, these solid phases can improve the solubility, bioavailability, dissolution rate, stability, and mechanical properties of the drug.

[0011] During the process of obtaining new solid phases, one can think of a large number of combinations with possible coformers; however, only some of these combinations generate a stable solid phase, as demonstrated in the description of this application.

[0012] Several metformin salts have been reported, but there remains a need for improved metformin salts with greater health benefits; in the present invention, the novel solid phases (NFS) of metformin resveratrol (METRES), metformin propionic acid (METAP), and metformin butyric acid (METAB) are innovative therapeutic alternatives for use in conditions related to metabolic syndrome, type II diabetes, hypercholesterolemia, obesity, and hypertension, among others.

[0013] The NFS of METAP and METAB comprise in their molecular structure metformin and short-chain fatty acids such as propionic acid and butyric acid, which have shown beneficial effects on the intestinal microbiota, in the reduction of insulin tolerance, reduction or control in the treatment of obesity, blood pressure control, better control of triglycerides, cholesterol and other conditions related to alterations of the metabolic syndrome.

[0014] Prior art efforts have been made to obtain solid forms of metformin. For example, document KR101104912B1 describes a MET cocrystal with nicotinic acid, document KR20130055391A discloses crystalline forms of metformin salts with Gava or Gaba derivatives, and document W02012090225A3 describes metformin cocrystals with oleylethanolamide.

[0015] BRIEF DESCRIPTION OF THE INVENTION

[0016] The present invention relates to metformin solid phases with improved physicochemical and biopharmaceutical properties, such as physical and chemical stability, which confer advantages for the preparation of compositions, such as improved bioavailability, solubility, and fewer adverse effects, compared to metformin hydrochloride, to obtain safe and effective therapeutic alternatives. These solid phases comprise metformin and a coformer consisting of at least one molecule with anticholesterolemic and antilipidemic properties, or other beneficial properties in the treatment of metabolic syndrome and related diseases.

[0017] The NFS of the present invention show beneficial effects in mice on a high-fat, high-sucrose diet, showing a reduction in insulin levels, improvement in insulin sensitivity, improvement in triglyceride and LDL cholesterol levels, among other conditions.

[0018] In the present invention, the new solid phases comprise: a) an amorphous solid phase comprising metformin and resveratrol (METRES coamorph) in a 1:1 molar ratio; b) a crystalline solid phase comprising metformin and resveratrol with ethyl acetate (METRES-AcOEt) in a 1:1:1 molar ratio; c) a crystalline solid phase comprising metformin and propionic acid (METAP) in a 1:1 molar ratio; and d) a crystalline solid phase comprising metformin and butyric acid (METAB) in a 1:1 molar ratio.

[0019] In another embodiment, the present invention relates to pharmaceutical compositions comprising coamorphous METRES, METRES-AcOEt, METAP, and METAB with improved physicochemical and biopharmaceutical properties.

[0020] The present invention provides methods for manufacturing the solid phases of metformin, comprising contacting the metformin base, obtained from metformin hydrochloride, with the coformer under suitable conditions.

[0021] In another embodiment, the present invention provides methods for treating conditions or diseases, such as diabetes and its comorbidities, metabolic syndrome and related diseases, cardiovascular diseases, and diseases involving inflammation. These treatment methods comprise the administration of NFS to a subject in need.

[0022] In another embodiment, the present invention provides uses of metformin NFS: METRES coamorph, METRES-AcOEt, METAP and METAB, to manufacture a pharmaceutical composition or drug for the prevention and / or treatment of the aforementioned conditions or diseases.

[0023] These and other embodiments of the present invention are described in more detail below.

[0024] BRIEF DESCRIPTION OF THE FIGURES

[0025] The figures illustrate the result of the characterization of the metformin NFS obtained in the present invention.

[0026] Figure 1. DRXP pattern of: a) metformin (MET) , b) resveratrol (RES) and c) the NFS METRES coamorph.

[0027] Figure 2. 1H-NMR spectrum of the NFS METRES coamorph in DMSO-d6.

[0028] Figure 3. FT-infrared spectrum of: a) metformin (MET), b) resveratrol (RES) and c) the coamorphous NFS METRES.

[0029] Figure 4. DRXP pattern of: a) metformin (MET) , b) resveratrol (RES) and c) the NFS METRES-AcOEt .

[0030] Figure 1H-NMR spectrum of the NFS METRES-AcOEt in DMSO-d6.

[0031] Figure 6. 13C-NMR spectrum of the NFS METRES-AcOEt in DMSO-d6.

[0032] Figure 7. Results of the TGA analysis of metformin (MET), resveratrol (RES) and the NFS METRES-AcOEt.

[0033] Figure 8. FT-infrared spectrum of: a) metformin (MET), b) resveratrol (RES) and c) the NFS METRES-AcOEt.

[0034] Figure 9. DRXP pattern of: a) metformin (MET) ; and b) the NFS ME TAP.

[0035] Figure 10. 1H-NMR spectrum of the NFS METAP in DMSO- d6.

[0036] Figure 11. 13C-NMR spectrum of the NFS METAP in DMSO- d6.

[0037] Figure 12. Results of the TGA analysis of metformin (MET) and NFS METAP. Figure 13. FT-Infrared spectrum of: a) metformin (MET), b) propionic acid (AP); and c) NFS METAP.

[0038] Figure 14. DRXP patterns of: a) MET, b) METAP and solids at the end of a 30-day stability test at: c) 40°C, d) 50°C and e) 40°C / 75% RH.

[0039] Figure 15. DRXP pattern of: a) metformin (MET) ; and b) the NFS ME TAB.

[0040] Figure 16. 1H-NMR spectrum of the NFS of METAB in DMSO- d6.

[0041] Figure 17. 13C-NMR spectrum of NFS METAB in DMSO- d6.

[0042] Figure 18. Results of the TGA analysis of metformin (MET) and NFS METAB.

[0043] Figure 19. FT-Infrared spectrum of: a) metformin (MET), b) butyric acid (AB) and c) NFS METAB.

[0044] Figure 20. DRXP patterns of: a) MET, b) METAB and solids at the end of a 30-day stability test at: c) 40°C, d) 50°C and e) 40°C / 75% RH.

[0045] Figure 21. PDX pattern of: a) MET, b) METAP, c) the solid recovered by filtration from the solubility experiments in BE pH 6.8 at 37°C; and d) the solid recovered from the evaporation of the filtrate.

[0046] Figure 22. PDX pattern of: a) MET, b) METAB, c) the solid recovered by filtration from the solubility experiments in BE pH 6.8 at 37°C; and d) the solid recovered from the evaporation of the filtrate.

[0047] DETAILED DESCRIPTION OF THE INVENTION

[0048] The present invention relates to novel metformin solid phases with improved pharmaceutical properties, comprising metformin and, as a coforming agent, a compound selected from resveratrol, short-chain fatty acids selected from propionic acid and butyric acid, among others.

[0049] In general, a salt is a chemical compound formed by cations (positively charged ions) and anions (negatively charged ions) in an equivalent proportion, which is held together by ionic interactions (an ionic bond).

[0050] A cocrystal is a homogeneous solid phase composed of two or more different chemical species, which are solid as pure compounds, and are typically held together by hydrogen bonds and other non-covalent interactions.

[0051] The term solvate refers to an aggregate or crystal formed during the crystallization process of a molecular or ionic compound that contains one or more solvent molecules within its crystal assembly in a stoichiometric or non-stoichiometric manner.

[0052] In the present invention, metformin NFS are obtained by combining the drug with a coformer, wherein said coformer is selected from compounds possessing hydroxyl, carboxyl, or phenol groups.

[0053] Resveratrol

[0054] Resveratrol (5-[(E)-2-(4-hydroxyphenyl)ethenyl]benzene-1,3-diol) (RES) is a naturally occurring polyphenol found in some foods, such as grape skins, peanuts, and red wine. As a phenolic compound, it contributes to the antioxidant potential of red wine and, therefore, may play a role in the prevention of various diseases, including cardiovascular, respiratory, and metabolic diseases, among others. This compound has also been found to modulate lipid metabolism and inhibit low-density lipoprotein oxidation and platelet aggregation. Additionally, it has been found to possess anti-inflammatory and anticancer properties. Resveratrol is a compound with low water solubility (0.03 mg / mL at 25°C), so it is considered a Class II compound of the Biopharmaceutical Classification System (BCS).

[0055] Fatty acids with a carbon chain of up to six atoms are considered short-chain fatty acids; the most relevant in human metabolism are acetate (C2), propionate (C3), and butyrate (C4). These compounds originate primarily from the fermentation of undigested dietary fiber in the colon by intestinal bacteria and are absorbed by non-ionic diffusion and active transport into colonocytes, for which butyrate is the main source of energy.

[0056] Short-chain fatty acids have been shown to regulate the structure of the gut microbiota, improve the function of the intestinal epithelial barrier, and are beneficial in slowing the progression of diseases related to metabolic disorders, gastrointestinal disorders, for example, type 2 diabetes (T2D), obesity, non-alcoholic fatty liver disease, chronic kidney disease (CKD), hypertension, infectious bowel disease (IBD), irritable bowel syndrome (IBS), and colorectal cancer (CRC).

[0057] Propionic acid

[0058] Propionic acid, also known as propanoic acid (PA), is a short-chain fatty acid and a major metabolite of the fermentation of undigested food by the gut microbiota. Propionate is derived, among other sources, from carbohydrate metabolism during glycolysis, primarily via the succinate pathway. This compound occurs naturally in some foods, such as milk and dairy products. Due to its antifungal and antibacterial effects, it is also used as a preservative in some foods.

[0059] It is known that PA decreases fatty acid content in the liver and plasma, reduces food intake, exerts immunosuppressive effects, and is believed to improve tissue insulin sensitivity. Therefore, an increase in PA production by the gut microbiota or in its intake could be considered beneficial in the context of preventing obesity or type 2 diabetes.

[0060] AP in mouse models of hypertension demonstrated that oral propionate treatment reduces the development of atherosclerosis, pathological cardiac hypertrophy, and fibrosis.

[0061] Butyric acid

[0062] Butyric acid (BA) is a short-chain fatty acid primarily produced by the colonic microbiota. 70-90% of BA is consumed by colonocytes, representing 70% of their energy source through beta-oxidation. BA has been found to play several beneficial roles in the gastrointestinal tract, including being an important regulator of colonocyte proliferation and apoptosis, gastrointestinal motility, and bacterial microbiota composition, as well as participating in immunomodulatory processes and anti-inflammatory activity. Additionally, butyrate is a potential agent for the treatment of irritable bowel syndrome.

[0063] Butyric acid is produced in the colon through the fermentation of dietary fiber. Because of this, quantifying butyric acid levels after administration is difficult, but it is known to have immunomodulatory and anti-inflammatory properties, presumably based on the topical inhibition of inflammatory mediators in the epithelium. Butyrate likely has a beneficial influence on the hypersensitivity of intestinal receptors, resulting in a decrease in intra-abdominal pressure. Furthermore, it improves intestinal peristalsis and the retractability of the surrounding muscular layer.

[0064] The solid phases, which in the present invention are also described as metformin salts, comprise a coforming agent selected from resveratrol, propionic acid, butyric acid, and have defined molar or stoichiometric ratios between MET and the coforming agent.

[0065] In another aspect, the novel salts comprising metformin with a selected coforming agent of resveratrol, propionic acid, and butyric acid are used as therapeutically valuable compounds that have a synergistic effect. Consequently, the novel solid phases are used as an enhanced antidiabetic agent.

[0066] In one embodiment, the pharmaceutical composition according to the present invention comprises pharmaceutically acceptable excipients that may be selected from the group consisting of a filling agent, a binding agent, a disintegrating agent, a preservative, a diluent, a flavoring agent, a sweetening agent, a lubricant, an oral dispersing agent, a colorant, a flavor masking agent, a pH modifier, a stabilizing agent, a compacting agent, and combinations thereof.

[0067] In certain formulations, the pharmaceutical composition may be presented in solid forms: tablets, powders, capsules, lozenges; liquids: syrups, suspensions, emulsions, elixirs, drops, ointments, gels; transdermal patches; and parenteral dosage forms. Such compositions may have different release profiles, for example, immediate-release, prolonged-release, or combinations thereof. The present invention also relates to methods for preparing the novel metformin salts, selected from rapid solvent evaporation, crystallization from solution, and milling. The methods for identifying and / or characterizing the novel solid phases consist of Powder X-ray Diffraction (PXRD), Fourier Transform Infrared Spectrometry (FT-IR), Differential Scanning Calorimetry - Thermogravimetric Analysis (DSC-TGA), and Proton Nuclear Magnetic Resonance (PNMR). 1H-NMR) or carbon ( 13 C-MRI) .

[0068] Table 1 describes the characteristics of Metformin NFS. Table 1 to 1

[0069] Obtaining NFS of Metformin with Resveratrol

[0070] Amorphous Metformin-Resveratrol NFS (amorphous METRES) Synthesis Method

[0071] Experiments to obtain a metformin NFS with the coformer resveratrol were performed in solution with the solvent ethyl acetate. For this, 0.13 mmol of resveratrol was dissolved at room temperature, and then small amounts of metformin (MET) were added until solid precipitation was obtained. The stirring time was 15 minutes. The XRD pattern of the resulting solid indicates that it is amorphous. Physically, the amorphous solid resulting from the metformin-resveratrol NFS has a light grayish-yellow color and is easy to handle and dry. Table 2 shows the experimental conditions for obtaining the amorphous MET NFS. Figure 1 shows the XRD spectrum of the raw materials: a) MET, b) resveratrol, and c) the resulting amorphous solid.

[0072] Table 2

[0073] Experiments were performed under similar conditions using other solvents such as acetone, n-butanol, and acetonitrile; however, in these cases, dark precipitates with an oily appearance were obtained, which were difficult to dry and handle. NMR characterization of coamorphous METRES

[0074] The METRES coamorphous solid was analyzed by proton nuclear magnetic resonance ( 1¹H-NMR) to determine the presence of MET and RES, and the stoichiometric ratio. In the NMR spectrum of the amorphous METRES sample (Figure 2), signals corresponding to specific protons from each of the MET and RES molecules are observed. The signal present at 2.88 ppm integrates for six protons from the two methyl groups (-CH3) present in the MET molecule. For the RES molecule, five groups of signals are observed in the range between 6.0 ppm and 7.21 ppm, integrating for a total of nine protons corresponding to the aromatic groups and the trans alkene. Therefore, the integration of the aforementioned signals confirms the 1:1 stoichiometry of this METRES solid phase.

[0075] FT-IR characterization of coamorphous METRES

[0076] Figure 3 shows the IR spectra of the coamorphous METRES and the raw materials. In the IR spectrum of MET in Figure 3a, the bands at 3416 CTÍT 1 and 3261 cnr 1that correspond to stretching vibrations of the NH bonds of the primary amine of the MET undergo a shift in wavenumber, as seen in the spectrum of coamorphous METRES (Figure 3c, indicating the formation of new bonds between the MET and the RES.

[0077] Crystalline NFS of Metformin - Resveratrol (METRES-AcOEt)

[0078] Synthesis method

[0079] Experiments to obtain a non-solid solution (NSS) of metformin with the coformer resveratrol were performed in solution with ethyl acetate solvent. For this purpose, 0.13 mmol of resveratrol was dissolved at room temperature, and then small amounts of metformin were added until precipitation of the solid was obtained. The stirring time was 5 hours. The resulting solid showed a characteristic XRD pattern of a crystalline solid. Physically, the crystalline solid is gray in color and easy to handle and dry. Table 3 shows the experimental conditions for obtaining the NFS of metformin and ethyl acetate.

[0080] As shown in Figure 4c, the NFS METRES-AcOEt exhibits a powder X-ray diffraction pattern comprising peak positions at angles 20°, selected from the group consisting of 9.48°, 14.46°, 15.17°, 16.71°, 17.64°, 18.43°, 20.39°, 22.38°, 23.74°, and 24.72°. In one aspect, METRES-AcOEt comprises peaks at the angles 20°: 14.46°, 16.71°,

[0081] 18.43°, 20.39°, 22.38°, or, it comprises peaks at the angles 20: 16.71°, 20.39°, 22.38°.

[0082] Table 3.

[0083] Experiments under similar conditions using other solvents such as acetone, n-butanol, and acetonitrile did not produce crystalline solids; rather, in these cases, dark precipitates with an oily appearance were obtained, which were difficult to dry and handle. Characterization by 1 H-MRI and 13 NFS C-MRI of METRES-AcOEt

[0084] The METRES-AcOEt crystalline solid was analyzed by proton nuclear magnetic resonance ( 1 1H-NMR) was used to determine the presence of MET and RES, the solvent, and the stoichiometric ratio. As shown in Figure 5, the signal at 2.87 ppm integrates for six protons from the two methyl groups (-CH3) present in the MET molecule. For the RES molecule, five groups of signals were observed in the range of 6.0 ppm to 7.22 ppm, integrating for a total of nine protons corresponding to the aromatic groups and the trans alkene. The integration of these signals confirms the 1:1 stoichiometry of metformin:resveratrol. In addition to the MET and RES signals, three more signals were observed at 4.02 ppm, 1.99 ppm, and 1.17 ppm, corresponding to ethyl acetate signals in a proportion close to one molar equivalent.

[0085] The spectrum of 13¹³C NMR (Figure 6) shows the signal at 36.98 ppm corresponding to the methyl groups at positions 3 and 4 of MET, while the carbons of the imino groups at positions 1 and 2 appear at 159.5 and 160.1 ppm. For resveratrol, eight signals were observed in the range between 101.8 ppm and 139.3 ppm, corresponding to the carbons of the phenyl rings at positions 6, 7, 10, 11, 12, and 18 (due to symmetry, carbons 14, 15, and 16 appear in the same position as 6, 11, and 12), and of the double bond at carbons 8 and 9. The phenolic carbons 5, 13, and 17 are located at 159.5 and 160.4 ppm. Additionally, signals were observed at 170.35, 59.76, 20.77 and 14.09, which correspond to carbons 19, 20, 21 and 22 of the ethyl acetate present in the sample.

[0086] TGA characterization of the NFS of METRES-AcOEt

[0087] The result of the thermogravimetric analysis of

[0088] METRES-AcOEt, shown in Figure 7, exhibits mass loss in two stages starting at Tonset 102°C. This behavior differs from that observed for the initial materials, as MET decomposes starting at Tonset 143°C, and RES decomposes starting at Tonset 269°C. The first mass loss of METRES-AcOEt corresponds to 18.3%, which is similar to one molar equivalent of ethyl acetate (approximately 19.7%). The second mass loss decreases steadily to 23% by mass at 450°C. No events attributable to mass loss of MET or RES are observed within this temperature range, suggesting simultaneous decomposition and evaporation of these two components of the NFS. This TGA result, in conjunction with the NMR spectra of 3 H and 13 C indicates that this NFS corresponds to a solvate with ethyl acetate in a MET : RES : AcOEt 1:1:1 ratio.

[0089] FT-IR characterization of the METRES-AcOEt NFS

[0090] Figure 8 shows the IR spectra of the crystalline solid METRES-AcOEt and the raw materials. In the IR spectrum of MET (Figure 8a), bands are visible at 3416 cnr 1 and 3261 cnr 1 which correspond to stretching vibrations of the NH bonds of the primary amine of MET, which undergo a shift in wavenumber at 3430 cnr 1 and 3324 cnr respectively (Figure 8c), indicating the formation of new hydrogen bonds between the MET and the RES. Additionally, a band is observed at 3075 cnr 1 which corresponds to the stretching vibrations of the NH bonds due to the formation of a salt by the transfer of a proton from the RES to one of the secondary amines of the MET.

[0091] Regarding RES, the band that corresponds to vibration stretching at 3180 cnr 1The -OH groups (Figure 8b) are not clearly observed in the IR spectrum of the crystalline NFS (Figure 8c) due to the presence of the band indicating salt formation at 3230 cnr 1 While the band corresponding to bending vibrations at 1381 cnr 1 of the -OH groups are shifted in the METRES-AcOEt spectrum (1375 cnr 1 ) which indicates the formation of new hydrogen bonds.

[0092] Crystalline NFS of Metformin and Propionic Acid (METAP)

[0093] Synthesis method

[0094] To obtain the non-solid phase (NSF) of metformin and propionic acid, metformin base was dissolved in ethanol or acetone with stirring at room temperature. Subsequently, propionic acid (PA) was added. The resulting solid was isolated by filtration and analyzed using various techniques. As shown in Figure 9, the obtained solid exhibited a characteristic XRD pattern of a crystalline solid, distinct from that of metformin, indicating the formation of a new solid phase, ME TAP.

[0095] The NFS METAP exhibits a powder X-ray diffraction pattern comprising peak positions at 20° angles, selected from the group consisting of 10.12°, 11.01°, 17.54°, 20.26°, 22.04°, 24.08°, 24.30°, 26.63°, 28.31°, 33.28°. In one aspect, the crystalline solid form of metformin and resveratrol comprises peaks at the 20° angles: 11.01°, 17.54°, 22.04°, 24.08°, 26.63°, or, alternatively, comprises peaks at the 20° angles: 11.01°, 22.04°, 26.63°.

[0096] 1H-NMR and 13C-NMR characterization of the NFS METAP

[0097] The NFS METAP was analyzed by 1 ¹H NMR in a DMSO-de solution. As shown in Figure 10, the signal at 2.90 ppm integrates for six protons corresponding to the two methyl groups present in the MET molecule. Furthermore, the signals at 0.89 ppm and 2.08 ppm integrate for the protons corresponding to the CH3 and CH2 groups of the AP molecule. This indicates that this crystalline METAP NFS contains one equivalent of each component without any solvent present. Table 4 shows the chemical shift and signal integration values ​​assigned to protons in the MET and AP molecules.

[0098] Table 4

[0099] The 13C-NMR spectrum in Figure 11 shows three signals assigned to the MET molecule: the signals at 159.1 and 160.3 ppm correspond to the guanidine carbons at positions 1 and 2, respectively, while the signal at 37.8 ppm corresponds to the methyl group carbons at positions 3 and 4. With reference to AP, the signals at 178.6, 31.5, and 11.7 ppm correspond to the carbons at positions 5, 6, and 7, respectively. The multiple signal at 39.5 ppm corresponds to the solvent used in the DMSO-d6 solution, and no additional signals are observed. This confirms the composition of the METAP solid.

[0100] TGA characterization of the NFS METAP

[0101] The thermogravimetric profile of NFS METAP differs from that of MET. The MET thermogram (Figure 12) shows a two-stage mass loss beginning at Tonset 143°C and reaching a residual mass of 5% at temperatures above 400°C. In contrast, NFS METAP exhibits a single mass loss at Tonset 178°C, indicating an increase in its thermal stability at 35°C. This result confirms that this solid phase is anhydrous. FT-IR characterization of NFS METAP

[0102] Figure 13 shows the IR spectra of the NFS METAP and the raw materials. The bands at 3416 cnr 1 and 3261 cnr 1 The vibrations corresponding to stretching vibrations of the NH bonds of the primary amine of MET (Figure 13a) shifted towards shorter wavelengths (Figure 13c), indicating the formation of new hydrogen bonds between MET and AP, confirming the generation of an NFS METAP. Additionally, a band appears at 3028 cnr1 which corresponds to the stretching vibrations of the NH bonds due to the formation of a salt as a consequence of the protonation of one of the secondary amines of MET. The band that appears at 1599 cnr 1 which corresponds to the bending vibrations of the NH bonds of the primary amine in MET, was no longer observed in NFS.

[0103] With respect to AP (Figure 13b), the bands that correspond to stretching vibrations at 3300-2500 and out-of-plane bending at 927 cnr 1 of the hydroxyl, already carbonyl stretching vibrations at 1708 cnr 1 They no longer appeared in the METAP spectrum. However, two new bands appeared at 1655 cnr 1 and 1397 cnr 1 in the NFS spectrum, suggesting the formation of the carboxylate anion from the AP molecule due to proton transfer from the carboxylic acid group to metformin. Therefore, this NFS METAP corresponds to a salt.

[0104] Stability Study

[0105] Stability studies were performed with the NFS METAP for one month under stress conditions: at 40°C, 50°C and a combination of 40°C and 75% RH.

[0106] Figure 14 shows the XRD patterns of: a) MET; b) the NFS of METAP; as well as the samples that were subjected to: c) 40°C, d) 50°C and e) 40°C / 75 %RH. For the patterns in Figures 14c, 14d and 14e, only peaks corresponding to the reference crystalline METAP phase are observed, without the presence of additional peaks that could indicate any phase transformation.

[0107] Crystalline NFS of Metformin and Butyric Acid (METAB)

[0108] Synthesis method

[0109] Based on previous experiments for obtaining the NFS of METAP, similar experimental procedures were followed to obtain the NFS of MET with butyric acid (AB). For these experiments, an AB solution in acetone was used, followed by the addition of MET and the stirring of the suspension. The suspended solid was isolated by filtration and analyzed by XRD (Figure 15). The XRD pattern of the resulting product (Figure 15b) shows novel diffraction peaks in positions different from the MET starting material, indicating the production of the NFS METAB.

[0110] The NFS of METAB exhibits a DRXP pattern comprising at least twenty peak positions at 20° angles, selected from the group consisting of 10.18°, 11.71°, 17.90°, 20.51°, 21.40°, 23.22°, 24.08°, 25.32°, 27.10°, 30.09°. In one aspect, the solid form of metformin butyrate (METAB) comprises peaks at the 20° angles: 10.18°, 11.71°, 20.51°, 21.40°, 25.32°.

[0111] 1H-NMR and 13C-NMR characterization of NFS METAB.

[0112] The NFS METAB was analyzed by 1¹H NMR (Figure 16) was used to determine the stoichiometric relationship between MET and AB. The signal at 2.90 ppm integrates for six protons and corresponds to the two methyl groups of the MET molecule. The signals at 0.82 ppm, 1.42 ppm, and 1.84 ppm integrate for the protons of the CH3 group and the CH2 groups in the alpha and beta positions, relative to the carboxylic acid of the AB molecule. Based on this result, a 1:1 molar ratio was established for this NFS. Table 5 presents the chemical shift and signal integration values ​​assigned to protons in the MET and AB molecules.

[0113] The 13C-NMR spectrum (Figure 17) shows three signals assigned to the MET molecule: the signals at 158.9 and 160.7 ppm correspond to the guanidine carbons at positions 1 and 2, respectively, while the signal at 37.8 ppm corresponds to the methyl group carbons at positions 3 and 4. Regarding AB, the signals at 177.6, 41.0, 20.1, and 14.9 ppm correspond to the carbons at positions 5, 6, 7, and 8, respectively. The multiple signal at 39.5 ppm corresponds to the solvent used in the DMSO-d6 solution, and no additional signals are observed, confirming the composition of the solid METAB.

[0114] TGA characterization of NFS METAB

[0115] A TGA calorimetric study was performed on the NFS METAB sample. The MET thermogram (Figure 18) shows a two-stage mass loss, beginning at Tonset 143 °C and reaching a residual mass of 5% at temperatures above 400 °C. Furthermore, the METAB sample begins to lose mass at Tonset 180 °C, indicating increased thermal stability compared to metformin at 37 °C. This result confirms that this solid phase is anhydrous. FT-IR characterization of NFS METAB

[0116] In the IR characterization (Figure 19), the position in the wavenumber of the bands that correspond to functional groups that can interact by hydrogen bonds coincides with that reported in the literature for MET and AB.

[0117] In the IR spectrum of the MET (Figure 19a), the bands at 3416 cnr 1 and 3261 cnr 1which correspond to stretching vibrations of the NH bonds of the primary amine of MET are shifted towards 3427 cnr 1 and 3320 cnr 1 in the spectrum of Figure 19c, indicating the formation of new hydrogen bonds between MET and AB, thus demonstrating the generation of the NFS METAB. Additionally, a band appears at 3128 cnr 1 which corresponds to the stretching vibrations of the NH bonds due to the formation of a salt as a consequence of the protonation of one of the secondary amines of MET. The band that appears at 1599 cnr 1 (Figure 19a) comprising the bending vibrations of the NH bonds of the primary amine in MET, in NFS (Figure 19c) is no longer observed.

[0118] With respect to AB (Figure 19b), the bands that correspond to stretching vibrations at 3300-2500 cnr 1 and out-of-plane bending at 929 cnr 1of the hydroxyl, already carbonyl stretching vibrations at 1704 cnr 1 These bands are no longer observed in the METAB spectrum (Figure 19c). However, two new bands appear at 1660 cnr in the latter. 1 and 1399 cnr 1 This suggests the formation of the carboxylate anion from the AB molecule due to proton transfer from the carboxylic acid group to metformin. Therefore, this NFS METAB corresponds to a salt. Stability Study

[0119] Stability studies were performed with the NFS METAB for one month under stress conditions: at 40°C, 50°C and a combination of 40°C and 75% RH.

[0120] Figure 20 shows the XRD patterns of: a) MET; b) the NFS of METAP; as well as the samples that were subjected to: c) 40°C, d) 50°C and e) 40°C / 75 %RH. For the patterns in Figures 20c, 20d and 20e, only peaks corresponding to the reference crystalline METAB phase are observed, without the presence of additional peaks that could indicate any phase transformation.

[0121] Determination of the solubility of solid NFS of Metformin

[0122] Experiments were performed to determine the solubility of the following metformin NFS: METRES-AcOEt, METAP, and METAB. The tests were performed using a phosphate buffer (BE) solution at pH 6.8 at 37°C under constant stirring.

[0123] The tests with each NFS were performed as follows: 1 mL of BF pH 6.8 was mixed with a sufficient amount of each NFS until the solid no longer dissolved, forming a saturated solution. The suspensions were then stirred for 24 hours at 37 °C, after which the samples were filtered. Each solid sample retained on the filter paper was dried at 30 °C and analyzed by XRD, yielding a first solid. The pH of the filtrate was measured, and the concentration of the compounds of interest in solution was quantified. Finally, the filtered solutions were evaporated to 30 °C to remove all the water, and once dry, they were analyzed by XRD to determine if the recovered solid phase was the same as the initial NFS and remained stable after this process, yielding a second solid.

[0124] In the case of NFS METRES-AcOEt, the diffraction pattern of the solid recovered by filtration after 24 h does not show the same pattern as the initial solid, but rather the one corresponding to RES. Therefore, the solubility of NFS METRES-AcOEt could not be determined using the procedure employed.

[0125] In the other NFS METAP and METAB (Figures 21 and 22) that were in contact with the aqueous medium for 24 h at 37 °C, the diffraction patterns of the solids recovered by filtration (Figures 21c and 22c) were similar to the original phases before the experiment. These results indicate that the METAP and METAB solids remain unchanged in contact with the saturated solution. This is relevant, since a reliable measurement of solubility could only be obtained in cases where the solid remains unchanged in contact with the saturated solution. It is also observed that the METAP and METAB solids reform after being dissolved in the filtered solution and recrystallize upon evaporation of the solvent (Figures 21d and 22d).

[0126] The results of the NFS solubility experiments are shown in Table 6. For comparison, the results for metformin base (>500 mg / mL of MET) and metformin hydrochloride (373 ± 13 mg / mL of MET) are also included.

[0127] The NFS METAP showed a metformin solubility value of 558 ± 18 mg / mL which is 1.5 times greater than the reference salt MET HC1.

[0128] For the NFS METAB assay, more than 1800 mg of the solid were added to observe undissolved material; it is evident that this solid is highly soluble (indicated as >500 mg / mL as a qualitative estimate) and solubilizes metformin at values ​​higher than the solubility of the reference salt. Table 6. Results of the solubilization experiments of the new metformin salts aThe experiments were performed by adding the indicated amount of solid to 1 mL of phosphate buffer pH 6.8 at 37 °C. This amount is sufficient to observe suspended solid in contact with the saturated solution.

[0129] Preclinical Studies: A preclinical study tested the effect of novel metformin phases—metformin-resveratrol, metformin-propionic acid, and metformin-butyric acid—on the growth, stress resistance, and longevity of the wild-type N2 strain of Caenorhabditis elegans. The results of this research demonstrated the beneficial effects of the new solid phases. These benefits were observed when evaluating three key parameters:

[0130] Impact on resistance to oxidative stress: The survival percentage of C. elegans subjected to oxidative stress conditions induced by NaAsO2 was analyzed. The data showed that metformin solid phases increased the nematodes' resistance to oxidative stress, suggesting a potential improvement in the antioxidant capacity of the compounds. Effect on lifespan under high glucose concentrations

[0131] For this experiment, the lifespan of C. elegans exposed to high concentrations of glucose was evaluated. The results indicated that the solid phases of metformin contributed to a significant prolongation of the nematodes' longevity compared to the controls.

[0132] Determination of survival curves

[0133] Survival studies were performed using Kaplan-Meier curves for nematodes cultured under standard conditions and exposed to the new solid phases of metformin. These analyses showed an increase in the overall survival of the nematodes.

[0134] The results of this study suggest a possible application of the NFS obtained in the management of disorders related to aging and metabolic and oxidative stress.

[0135] In another preclinical study, the effects of novel solid-phase metformin (metformin-resveratrol, metformin-propionic acid, metformin-butyric acid) were evaluated in male mice fed a high-fat, high-sucrose diet for 12 to 14 weeks. Once obesity was established, treatment was initiated by administering the novel solid-phase metformin orally for 4 to 5 weeks.

[0136] Weight gain, body composition, and fasting glucose and insulin levels were monitored. In addition, metabolic parameters such as adiponectin, leptin, total cholesterol, and LDL cholesterol were measured; as well as markers of liver damage such as ALT and AST; markers of renal function such as creatinine and urea; and markers related to inflammation, such as IL-6. Thermogenesis activation was also assessed using the UCP1 and PGC1 markers, and adipocyte size distribution was determined. Finally, changes in microbiota structure and short-chain fatty acid concentration were analyzed in stool samples collected 5 days before the end of the study.

[0137] The results showed a decrease in weight gain, as well as less lean mass loss and a reduction in fat mass gain. Glucose tolerance and insulin levels improved after 4 weeks of treatment. A decrease in triglyceride, LDL cholesterol, and pro-inflammatory cytokine levels, such as IL-6, was also observed.

[0138] These studies show that NFS represent a significant innovative advance as they comprehensively address multiple aspects of metabolic diseases such as insulin resistance, inflammation, and oxidative stress. These NFS have the potential to offer an innovative therapeutic alternative in the problem of metabolic syndrome and conditions related to metabolic alterations.

Claims

NOVELTY OF THE INVENTION Having described the present invention as above, the contents of the following are considered novel and, therefore, are claimed as property. CLAIMS 1. A solid phase comprising metformin and a coforming agent, wherein the coforming agent is selected from the group consisting of resveratrol, butyric acid, and propionic acid.

2. The solid phase according to claim 1, wherein the coforming agent is propionic acid and the molar ratio metformin : coformer is 1:

1.

3. The solid phase according to claim 1, wherein the coforming agent is butyric acid and the molar ratio metformin : coformer is 1:

1.

4. The solid phase in accordance with claim 1, where the coforming agent is resveratrol and the solid phase corresponds to a solvate with a molar ratio metformin : coformer : solvent equal to 1:1:

1.

5. The solid phase according to claim 4, wherein the solid phase exhibits powder X-ray diffraction peaks at angles 20° at 20.39, 16.71, 22.38, 14.46 and 18.

43.

6. The solid phase in accordance with claim 2, where the solid phase exhibits powder X-ray diffraction peaks at angles 20 at 22.04, 11.01, 26.63, 24.08, 17.

54.

7. The solid phase in accordance with claim 3, where the solid phase exhibits powder X-ray diffraction peaks at angles 20 at 10.18, 25.32, 11.71, 20.51, 21.

40.

8. The solid phase of claims 1 to 7, wherein the solid phase is a crystalline salt.

9. The solid phase according to claim 1, wherein the coforming agent is resveratrol and the molar ratio metformin: coformer is 1:

1.

10. The solid phase according to claim 9, wherein the solid phase is a coamorphous solid.

11. The solid phase according to any of the preceding claims, wherein the metformin is freebase metformin.

12. A pharmaceutical composition characterized in that it comprises the solid phase in accordance with any of claims 1 to 11 and pharmaceutically acceptable excipients.

13. The use of the solid phase according to any of claims 1 to 11, in the manufacture of a medicament for the treatment and / or prevention of diseases or symptoms selected from the group consisting of hyperglycemia, cardiovascular risk, cardiovascular disease, obesity, high blood pressure (HTA), diabetes, type I diabetes, type II diabetes, hyperlipidemia, fatty liver, obesity and / or reduction of blood cholesterol levels.

14. Use in accordance with claim 13, wherein the disease or symptom is metabolic syndrome or diabetes.

Images