Liquid formulations of folates

Abstract

The present invention relates to formulations of folate, in particular D-glucosamine 5-methyl-(6S)-tetrahydrofolate, in the form of a suspension in a mixture of medium chain triglyceride oil and stearin. Medium chain triglyceride oil and stearin having a water content of less than 0.5 wt% and a free glycerol and / or ethylene glycol content of less than 2 wt% are preferably used. The invention also discloses a method for preparing the preparation.

Description

[0001] The present invention relates to a folate formulation in the form of a suspension in a mixture of medium-chain triglyceride oil and stearin. BACKGROUND

[0003] Folic acid (i.e. N-[4-[[(2-amino-1,4-dihydro-4-oxo-6-pteridinyl)methyl]amino] benzoyl]-L-glutamic acid) and folates (the anion thereof) are water-soluble vitamin B9 and precursors of dihydrofolic acid and tetrahydrofolic acid and the respective anion thereof. They occur naturally in food, mainly as their conjugates, especially in liver, kidney, yeast, fruits and green leafy vegetables, and can also be taken as a supplement. The commercially available folic acid as a derivative thereof described above is yet to be synthetically prepared.

[0004] Folic acid occurs as a yellow or yellow-orange crystalline powder and is only slightly soluble in water and insoluble in alcohol; it is readily soluble in dilute solutions of alkali hydroxides and carbonates. Aqueous solutions of folic acid are sensitive to heat and rapidly decompose in the presence of light and / or riboflavin; therefore, solutions should be stored in the cool and protected from light.

[0005] B vitamins help the body convert carbohydrates into glucose, which is then metabolized to produce energy. These vitamins are essential for the breakdown of fats and proteins and play an important role in maintaining muscle tone of the digestive tract and in promoting the health of the nervous system, skin, hair, eyes, mouth and liver.

[0006] Folic acid is known to be essential for the production and maintenance of new cells. This is particularly important during periods of rapid cell division and growth, such as infancy and pregnancy. Replicating DNA requires folate. Therefore, folate deficiency hinders DNA synthesis and cell division, with the greatest clinical impact being on the bone marrow, which is a site of rapid cell turnover. Because RNA and protein synthesis are not hindered, large red blood cells, i.e. megaloblasts, are produced, leading to megaloblastic anemia, such as megaloblastic anemia (as can be seen in celiac disease) and nutritional anemia, or during pregnancy, infancy or childhood. Therefore, folate is needed by both adults and children to produce normal red blood cells and to prevent anemia. Folate also helps to prevent DNA changes that can lead to cancer.

[0007] Tetrahydrofolic acid and its derivatives are highly unstable, particularly due to their susceptibility to oxidation.

[0008] In particular, 5-methyltetrahydrofolic acid has importance as a pharmaceutical ingredient, mainly in oncology, as an adjuvant therapy to methotrexate and 5-fluorouracil treatments, and for the treatment of folic acid deficiency anemia associated with pregnancy, antibiotic therapy, etc.

[0009] FR 2137186 describes water-soluble alkylammonium salts of folic acid.

[0010] Among folates and reduced folates, mention can be made of calcium salts as the most relatively stable derivatives: US 5817659 and US 6441168 disclose crystalline salts of 5-methyl-(6R,S)-, -(6S)- or -(6R)-tetrahydrofolic acid, preferably calcium salts, having at least one equivalent of crystalline water per equivalent of the acid. 5-methyltetrahydrofolate calcium is the only folate derivative on the market that is able to directly cross the blood-brain barrier without further metabolism. Naturally occurring 5-methyltetrahydrofolate is only in the S form; the R form is biochemically inactive and is excreted by the kidneys.

[0011] The insolubility of these salts in water has been reported. In addition to this, numerous compositions for human and animal consumption comprising folates and / or reduced folates are disclosed, in various forms and together with vitamins, arginine, lysine, thiamine and / or other active ingredients, for example in US 5817659, US 5997915, US 6093703, US 6241996, US 6254904, US 6261600, US 6271374, US 6440450, US 6441168, US 6444218, US 6451360, US 6514973, US 6544944, US 6596721, US 6605646, US 6673381, US 6808725, US 6914073, US 6921754, US 6995158, US 20020094970, US 20040219262, US 20050113332, US 20060063768, US 2021338572, as nutritional supplements or for the treatment and prevention of various diseases, such as neurological diseases, pathopsychological diseases, cardiovascular diseases, arthritis and inflammatory conditions.

[0012] EP 2 245 032 (WO 2009103334) discloses water-soluble crystalline or amorphous D-glucosamine and D-galactosamine folates, in particular D-glucosamine salts of 5-methyl-5-methyl-(6S)-tetrahydrofolic acid.

[0013] Liquid formulations of folates are generally available as dietary supplements or as prescription drugs, for example disclosed in WO2017112588.

[0014] Liquid formulations of folates offer several advantages over traditional tablet or capsule forms, in particular for individuals who have difficulty swallowing or absorbing solid oral medications. Liquid folate supplements are generally easier to take, in particular for children, the elderly or individuals with difficulty swallowing.

[0015] Liquid folate formulations are typically in the form of oral solutions or suspensions. These products contain measured amounts of folate, usually expressed in micrograms (mcg) or milligrams (mg). They are designed to be administered orally by measuring the appropriate dose using a dropper, syringe or measuring device provided.

[0016] In view of the solubility properties of folates, most known liquid formulations are essentially aqueous. However, known liquid formulations suffer from stability problems, limiting their widespread use.

[0017] Invention description

[0018] It has now been found that stable oily liquid formulations of folates can be obtained by suspending the active ingredient in a mixture of medium chain triglyceride oil and hard fat.

[0019] In a first embodiment, the present invention accordingly provides a formulation of a folate in the form of a suspension in a mixture of medium chain triglyceride oil and hard fat.

[0020] The term "folate" means folic acid, dihydrofolic acid, tetrahydrofolic acid, unsubstituted or substituted by a 5-methyl-, 5-formyl-, 10-formyl-, 5,10-methylene-, 5,10-methenyl- moiety, in (6R,S), (6S) or (6R) configuration, salts or derivatives thereof.

[0021] Sodium, calcium or glucosamine salts in amorphous or crystalline form are preferred, in particular the D-glucosamine salt disclosed in EP 2 245 032.

[0022] Examples of preferred folates include D-glucosamine-folate, D-galactosamine-folate, D-glucosamine (6R,S)-tetrahydrofolate, D-glucosamine (6S)-tetrahydrofolate, D-glucosamine (6R)-tetrahydrofolate; D-galactosamine (6R,S)-tetrahydrofolate, D-galactosamine (6S)-tetrahydrofolate, D-galactosamine (6R)-tetrahydrofolate; D-glucosamine 5-methyl-(6R,S)-tetrahydrofolate, D-glucosamine 5-methyl-(6S)-tetrahydrofolate, D-glucosamine 5-methyl-(6R)-tetrahydrofolate; D-galactosamine 5-methyl-(6R,S)-tetrahydrofolate, D-galactosamine 5-methyl-(6S)-tetrahydrofolate, D-galactosamine 5-methyl-(6R)-tetrahydrofolate. D-glucosamine 5-methyl-(6S)-tetrahydrofolate is particularly preferred.

[0023] The term "medium-chain triglyceride oil" refers to triglycerides of fatty acids having two or three aliphatic chains of 6-12 carbon atoms (i.e. medium-chain fatty acids). The oil is commercially available from several sources and can be obtained from palm kernel oil and coconut oil.

[0024] The weight ratio of the included medium-chain triglyceride oil and hard fat is preferably 10:1 to 90:1.

[0025] The water content of the hard fat (E 570) and MCT (medium-chain triglyceride) oil is preferably below 0.5% by weight.

[0026] The weight concentration of the folate in the formulation according to the present application ranges from 0.01% to 5.0%.

[0027] According to a second embodiment, the present application provides a method for preparing a stable oily suspension of a folate, the method comprising:

[0028] - dispersing hard fat in medium-chain triglyceride (MCT) oil at 70°C,

[0029] - cooling to 30°C under stirring;

[0030] - adding the folate to the turbid oily suspension under stirring at room temperature.

[0031] The formulation according to the present application is characterized by the stability of the active ingredient at temperatures up to 40°C for 90 days or more at a relative humidity of 75% (RH) without any noticeable colour change.

[0032] Formulations prepared using conventional excipients and carriers (e.g. glyceryl dimyristate, polyoxyethylene (20) sorbitol, beeswax derivatives, silicon dioxide, polyglyceryl-3-oleate, magnesium stearate, sunflower lecithin, glyceryl di-stearate, polyethylene glycol (PEG 400)) have not been successfully proven to obtain satisfactory stability: suspensions prepared with said components were observed to rapidly brown, resulting in degradation of the active ingredient. Even the addition of antioxidants (e.g.: ascorbic acid, alpha-tocopherol, sodium sulphite, butylated hydroxyanisole, sodium ascorbate) did not have a positive effect on the stability of the suspension.

[0033] The present application is described in more detail in the following examples.

[0034] Example 1

[0035]

[0036] (*) equivalent to 460 mcg of 5-MTHF acid (calculated at a drug substance assay of 51.10%) and containing a 15% overdose.

[0037] Example 2

[0038]

[0039] (*) equivalent to 4.0 mg of 5-MTHF acid (calculated as drug substance at 51.10%) and containing a 15% overdose.

[0040] Example 3

[0041]

[0042] (*) equivalent to 460 meg of 5-MTHF acid (calculated as drug substance at 82.00%) and containing a 15% overdose.

[0043] Example 4

[0044]

[0045] (*) equivalent to 460 meg of 5-MTHF acid (calculated as drug substance at 83.10%) and containing a 15% overdose.

[0046] Example 5

[0047]

[0048] (*) equivalent to 460 meg of 5-MTHF acid (calculated as drug substance at 79.00%) and containing a 15% overdose.

[0049] Example 6

[0050]

[0051] (*) equivalent to 460 meg of 5-MTHF acid (calculated as drug substance at 100.00%) and containing a 15% overdose.

[0052] Example 7

[0053]

[0054] (*) equivalent to 460 meg of 5-MTHF acid (calculated as drug substance at 51.10%) and containing a 15% overdose.

[0055] Example 8

[0056] To provide further evidence regarding the different active ingredients, liquid formulations of crystalline calcium salt 5-MTHF were prepared using the same combination of excipients (MCT oil and hard fat).

[0057]

[0058] Example 9 Stability testing

[0059] The stability of the formulation of Example 1 was tested at 5°C, 25°C, 30°C and 40°C at 75% RH. Normalized results are reported in the table below:

[0060] Table 1

[0061]

[0062] Table 2

[0063]

[0064] Table 3

[0065]

[0066] Table 4

[0067]

[0068] Example 10 Stability testing

[0069] The stability of the formulation of Example 8 was tested at 40°C at 75% RH. Normalized results are reported in the table below.

[0070] Table 5

[0071]

[0072] As shown by the recovery and purity values, the stability of the formulation containing the calcium salt was substantially equivalent to the stability of the glucosamine salt of 5-MTHF.

Claims

1. A formulation of folic acid salts, in the form of a suspension in a mixture of medium-chain triglyceride oil and stearin.

2. The formulation according to claim 1, wherein the folic acid is in the form of an amorphous or crystalline sodium salt, calcium salt, or glucosamine salt.

3. The formulation according to claim 1 or 2, wherein the folic acid is selected from folic acid, dihydrofolate, tetrahydrofolate, and is unsubstituted or partially substituted with 5-methyl-, 5-formyl-, 10-formyl-, 5,10-methylene-, or 5,10-methimethylene-, having a (6R,S), (6S), or (6R) configuration, preferably D-glucosamine-folate, D-galactosamine-folate, D-glucosamine(6R,S)-tetrahydrofolate, D-glucosamine(6S)-tetrahydrofolate, or D-glucosamine(6R)-tetrahydrofolate; D-galactosamine(6R,S) D-galactosamine (6S)-tetrahydrofolate, D-galactosamine (6R)-tetrahydrofolate; D-glucosamine 5-methyl-(6R,S)-tetrahydrofolate, D-glucosamine 5-methyl-(6S)-tetrahydrofolate, D-glucosamine 5-methyl-(6R)-tetrahydrofolate; D-galactosamine 5-methyl-(6R,S)-tetrahydrofolate, D-galactosamine 5-methyl-(6S)-tetrahydrofolate, D-galactosamine 5-methyl-(6R)-tetrahydrofolate, more preferably D-glucosamine 5-methyl-(6S)-tetrahydrofolate.

4. The formulation according to any one of claims 1 to 3, wherein the medium-chain triglyceride oil and stearin have a water content of less than 0.5% by weight and a free glycerol and / or ethylene glycol content of less than 2% by weight.

5. The formulation according to any one of claims 1 to 4, wherein the weight ratio of medium-chain triglyceride oil to stearin contained therein is 10:1 to 90:

1.

6. The formulation according to any one of claims 1 to 5, wherein the weight concentration of folic acid, its salt or derivative ranges from 0.01% by weight to 5.0% by weight.

7. A method for preparing the formulation of claims 1 to 6, the method comprising: - Disperse stearin in MCT oil at 70°C. - Cool to 30°C with stirring; - Add folic acid to the turbid, oily suspension while stirring at room temperature.

8. The method of claim 7, wherein the folic acid is a glucosamine salt.

9. The method according to claim 8, wherein the folate is D-glucosamine 5-methyl-(6S)-tetrahydrofolate.

Images