WO2020226889A1

WO2020226889A1 - Formulations of uridine triacetate in triacetin

Info

Publication number: WO2020226889A1
Application number: PCT/US2020/029060
Authority: WO
Inventors: Fedor Evgenievich Romantsev; Reid W. Von Borstel
Original assignee: Wellstat Therapeutics Corporation
Priority date: 2019-05-07
Filing date: 2020-04-21
Publication date: 2020-11-12

Abstract

This invention provides a solution comprising uridine triacetate dissolved in a solvent, wherein the solvent comprises triacetin. Diacetin can be added if the solution contains water or will be used in an aqueous environment. The solution of this invention and formulations comprising that solution are useful for administering uridine triacetate to a patient.

Description

FORMULATIONS OF URIDINE TRIACETATE IN TRIACETIN

BACKGROUND OF THE INVENTION

Liquid formulations of drugs that must be administered in relatively large quantities are generally more acceptable to patients than solid formulations. This is especially the case when doses are variable based on body weight or body surface area, as is the case for several important indications for uridine triacetate, such as hereditary orotic aciduria or mitochondrial cytopathies. A liquid formulation is particularly

advantageous for infants or for patients with swallowing difficulties or who must receive medications via gastrostomy or nasogastric tubes. A liquid formulation of uridine triacetate would be desirable, but the poor solubility of uridine triacetate in most solvents is a challenge

SUMMARY OF THE INVENTION

This invention provides a solution comprising uridine triacetate dissolved in a solvent, wherein the solvent comprises triacetin (glyceryl triacetate). The solution of this invention, and formulations comprising that solution are effective ways of administering uridine triacetate to a patient.

The solubility of uridine triacetate in water is less than 15 mg/ml, and even in a panel of versatile solvents, most of which cannot be given to humans as excipients, the maximum solubility was found to be 240 mg/ml or less (Table 1). Uridine triacetate was also not freely soluble in short chain triglycerides such as tributyrin, trihexanoate, tricaprylin, or in coconut oil (comprising medium-chain triglycerides), or in glycerol, the backbone for triglycerides (Table 2). Uridine triacetate is also not soluble in standard pharmaceutical liquid vehicles, syrups, or solvent such as propylene glycol, polyethylene glycol or ethanol. This invention is based, in part, on the unexpected discovery that triacetin permits solubilization of more than 600 mg/ml of uridine triacetate, as demonstrated in the examples below. DETAILED DESCRIPTION OF THE INVENTION Definitions and Abbreviations

As used herein the transitional term“comprising” is open-ended. A claim utilizing this term can contain elements in addition to those recited in such claim. UTA: uridine triacetate ; 2’,3’,5’-tri-O-acetyluridine.

5FU: 5-fluorouracil

UTP: uridine triphosphate

MTBE: Methyl tert-butyl ether

THF: tetrahydrofuran

PEG: polyethylene glycol

Triacetin; glyceryl triacetate

Diacetin; glyceryl diacetate; diacetyl glycerol

RTA: renal tubular acidosis

GI: gastrointestinal

FdUMP: Fluorodeoxyuridine monophosphate

TS: thymidylate synthase

DNA: deoxyribonucleic acid

RNA: ribonucleic acid

Solutions of the Invention In accordance with this invention, the solution can contain any concentration of uridine triacetate up to and including a saturated solution. In embodiments of this invention the concentration of uridine triacetate in the solution is from twenty percent to sixty percent by weight (20% (w/w) to 60% (w/w)), or more specifically from forty-six percent to sixty percent by weight (46% (w/w) to 60% (w/w)). Likewise the solution can contain any concentration of triacetin. In a more specific embodiment, the concentration of triacetin in the solution is at least twenty-eight percent by weight (28% (w/w)). The solution can further comprise one or more additional ingredients conventional in the art, including, but not limited to Tween, polyethylene glycol, acetyl triethyl citrate, glycerol trihexanoate, triethyl 2-acetylcitrate, and poly(D,L-lactide-co- glycolide). In a more specific embodiment the Tween is selected from the group consisting of Tween80, Tween40, and Tween20. In another embodiment the polyethylene glycol is PEG400.

The solution in accordance with this invention can be made by combining the uridine triacetate with the solvent, thereby yielding the solution. When the solution is to contain other ingredients, the method preferably comprises combining the uridine triacetate with the triacetin and then adding the one or more additional ingredients, thereby yielding the solution. Alternatively the ingredients can be combined in a different order. It is convenient to perform the combining step or steps at a temperature between 100°C and 115°C. The solution may then be cooled to a temperature between 20°C and 25 °C. It is important that such metastable or supersaturated solutions be protected from particulate matter or other impurities that may act as crystallization nuclei, which can cause premature precipitation. Uridine triacetate can stay in solution at concentrations for periods of years, if not indefinitely, at ambient room temperature (20-25° C) if carefully prepared and stored.

Pediatric formulation

A liquid formulation that can be administered via oral syringe is ideal for infants and young children as well as adults. Solid formulations of crystalline drugs, including granules or powders, are difficult to administer to infants, as they cannot generally be given mixed into solid or semisolid foods to nursing or bottle-fed children, and the granules may not stay suspended when liquids are used to try to deliver them via syringe or infant dosing spoon in a milk or formula vehicle. Importantly, uridine triacetate was found to be soluble in a relatively small volume of triacetin, limiting the total volume that must be administered to a child to deliver a therapeutic dose.

Sustained elevation of plasma uridine and Improved bioavailability

Administration of uridine triacetate in triacetin or triacetin/diacetin resulted in maintenance of elevated plasma uridine for a longer time compared to administration of a suspension that did not contain triacetin or diacetin, as demonstrated in Example 7 below. The use of triacetin or triacetin /diacetin formulations can reduce the number of uridine triacetate doses required per day to maintain plasma uridine at a maximally-effective concentration for elevating intracellular uridine nucleotides. A formulation according to this invention can be administered one, two, or three times per day, for example.

In addition, formulations of uridine triacetate dissolved in triacetin have better bioavailability than formulations containing crystalline or granular uridine triacetate. The bioavailability of oral uridine is 7-10 % in humans, as well as in mice. Solid or suspension formulations of crystalline or powdered uridine triacetate, administered as granules or tablets, deliver 4-6 times more uridine systemically than do equivalent oral doses of uridine in both species, for an absolute bioavailability of approximately 50%. Relatively high doses of uridine triacetate are required for many of its important clinical indications, so improvement of oral bioavailability is a major advantage. Improving bioavailability above 50% would allow patients to achieve therapeutic benefit at lower doses or improve therapeutic effects at a given oral dosage.

Gelatin capsule formulations Liquid formulations of drugs can be delivered in gelatin capsules or“gel caps”, which can contain a volume of liquid exceeding 1 ml, yet still be acceptable for swallowing by most patients. A solution of uridine triacetate in triacetin can contain more than 65% uridine triacetate by volume, permitting loading of amounts in the range of 1 gram of uridine triacetate into each gelatin capsule. This is a higher per-capsule load than has been possible for acceptable tablet formulations comprising solid excipients. Gelatin capsules reduce the bitter taste of uridine triacetate better than is possible in tablet or granule formulations due to the physical barrier between the drug and the tongue. Gelatin capsules can also protect acid-sensitive drugs from hydrolysis by stomach acid, thereby improving overall oral bioavailability. Uridine triacetate is an acetate ester prodrug subject to acid-catalyzed hydrolysis of the acetate prodrug moieties that are critical for efficient delivery of circulating uridine from the gastrointestinal tract. Thus the solutions and formulations of this invention can be encapsulated in a gel cap. Benefits of triacetin co-administered with uridine triacetate

Triacetin is an exceptionally benign excipient, yielding only acetate and glycerol when ingested and metabolized; both are primary intermediary metabolites in human nutritional biochemistry. Because it has a high density and can be completely metabolized, triacetin has been considered as a possible source of food energy in artificial food storage and regeneration systems on long space missions. It is believed to be safe to obtain more than half of one's dietary energy from triacetin. Shapira, J. et al.,“Current research on regenerative systems”, Life Sci Space Res. 7:123-9, 1969.

Triacetin and other short-chain triglycerides or diglycerides can provide alternative non-glucose fuels that are usable by the brain, e.g., acetate and glycerol. Uridine is also efficiently transported across the blood-brain barrier and can provide an efficient alternative fuel for the brain, via metabolism of the ribose moiety, and also provides benefits by improving bioenergetic efficiency via activation of the mitochondrial ATP-sensitive potassium channel by intracellular UDR

Formulations in accordance with this invention can be utilized to deliver uridine triacetate for any conventional treatment or preventative purpose. For example, uridine triacetate can be used to treat mitochondrial disorders as described in WO 2000/011952 (Wellstat Therapeutics Corp.) and WO 2000/050043 (The Regents of the University of California), the contents of which are incorporated herein by reference. Formulations of this invention are particularly useful in the treatment of renal tubular acidosis, since exogenous acetate can compensate for renal loss of bicarbonate.

Acetate moieties from uridine triacetate and triacetin work together for amelioration of renal tubular acidosis (RTA), in addition to the effect of uridine on RTA, especially in patients with RTA secondary to mitochondrial dysfunction, whether due to a primary mutation or secondary influences on mitochondrial function such as cystinosis or drug toxicities. In the treatment of RTA and other mitochondrial disorders in a human subject, a suitable dosage of the formulation in accordance with this invention contains from 500 milligrams to 3 grams per meter-squared of body surface area, ad ministered once, twice, three times, or four times per day. Preferably the amount of triacetin is an amount sufficient to solubilize the uridine triacetate at concentrations ranging from 20% to 60% uridine triacetate (w/v), more preferably about 50% uridine triacetate (w/v). Solid dosage forms of uridine triacetate

This invention provides a uridine triacetate formulation comprising the solution. The formulation can further comprise one or more pharmaceutically acceptable excipients. Examples of suitable pharmaceutically acceptable excipients include, but are not limited to, a long-chain triglyceride, a dark chocolate, a fish oil, glycerol, and diacetyl glycerol. The formulation may be a clear liquid, a slow-moving clear liquid, a semi gel, a slightly hazy liquid, or a solid.

Coformulation with triacetin and long chain triglycerides unexpectedly yields semisolid formulations with useful properties for administration to patients, and contain a high load of uridine triacetate per volume of material. Such formulations have improved taste characteristics. In one embodiment, coformulation of uridine triacetate in triacetin with dark chocolate yields a waxy-solid material with satisfactory taste and consistency for oral administration.

Water soluble formulations enabled with diacetin

Triacetin is not freely miscible with water. Aqueous formulations and formulations that are suitable for use in an aqueous environment are important for some therapeutic applications, such as mouth rinses for counteracting mucosal toxicity of 5-fluorouracil and other antimetabolites or cancer chemotherapy agents that interfere with pyrimidine metabolism. It was unexpectedly found that diacetin (diacetylglycerol), added to solutions of uridine triacetate in triacetin, enables preparation of aqueous solutions or solutions that are suitable for use in an aqueous environment. Diacetin, like triacetin, is classified as a food additive, and is metabolized to yield only acetate and glycerol. Therefore in accordance with this invention, in addition to uridine triacetate and triacetin, the solution may further comprise diacetin. In one

embodiment the concentration of diacetin in the solution is from forty percent to sixty-seven percent by volume (40% (v/v) to 67% (v/v)).

The optional addition of diacetin (glycerol diacetate) enables improved aqueous solubility, enabling preparation of stable aqueous solutions of uridine triacetate and permitting coformulation of uridine triacetate with water-soluble excipients and drugs as a solution, rather than as an emulsion or suspension. Therefore the solution may optionally comprise water. In an embodiment, the concentration of water in the solution is up to sixty percent by volume (60% (v/v)). In another embodiment the concentration of water in the solution is from three percent to sixty percent by volume (3% (v/v) to 60% (v/v)). In accordance with this invention the solution can contain any amount of water as long as the solution as a whole is either clear or a milky emulsion. It is convenient for the concentration of diacetin to water to be at least 0.55 by volume, or more specifically from 0.55 to 10 by volume.

For prevention or treatment of mucositis caused by antimetabolites such as fluorouracil, capecitabine, or methotrexate, an aqueous mouth rinse is suitable, and can be used multiple times per day as required, before, during or after administration of the chemotherapy.

The aqueous formulations are optionally sweetened or flavored with pharmaceutically acceptable excipients, including but not limited to sucralose, aspartame, saccharin, stevia, mogrosides, or sugar alcohols such as erythritol, sorbitol, or xylitol. Dextrose, sucrose, fructose or maltodextrin are optionally also used as sweeteners, though noncaloric sweeteners or sugar alcohols are preferred as they do not support bacterial growth. Standard flavoring agents known in the art are used to mask or modify perception of the bitter taste of pyrimidine nucleoside esters and of triacetin itself, and are used in quantities sufficient for taste modification not exceeding safe

concentrations.

Additional excipients or active agents known to be helpful in ameliorating chemotherapy-induced mucositis are optionally coformulated or coadministered with uridine triacetate or thymidine diacetate in an aqueous vehicle comprising triacetin, diacetin or a mixture of triacetin and diacetin. Such additional constituents include but are not limited to antihistamines such as diphenhydramine, protectants such as sucralfate, and corticosteroids or other anti-inflammatory agents. The concentrations of such constituents are in ranges known in the art to be beneficial and well-tolerated.

Topical and mouth rinse formulations

Liquid or gel or ointment formulations comprising uridine triacetate dissolved in triacetin, optionally comprising other excipients and active agents, are useful topical agents to reduce or prevent local toxicities of 5 -fluorouracil (5FU; which can also be delivered orally in the form of its prodrugs capecitabine, S-1, UFT or tegafur) to mucosal surfaces in the gastrointestinal (GI) tract, especially the mouth. Stomatitis, inflammation and ulceration of oral mucosa, is a painful, debilitating side effect of 5FU, as is mucosal damage throughout the GI tract; mucosal injury can permit bacteria and other pathogens from the intestine to enter the circulation and cause systemic infections which may be fatal.

Application of liquid formulations of uridine triacetate of the disclosure to the mouth, for example as a mouthwash used one to several times per day, for the before, during, or after infusion of 5FU reduces the severity of stomatitis, mucositis or ulceration. In an alterative embodiment, a solution of uridine triacetate, optionally including thymidine diacetate is incorporated into a mucoadhesive gel or paste for improved delivery to mucosal surfaces in the mouth.

5FU treatment, especially during a prolonged infusion or when 5FU is delivered with daily oral capecitabine, can cause cutaneous toxicity, particularly“hand-foot syndrome” affecting the palms and soles, involving pain, erythema, cracked and peeling skin, stinging, swelling and blistering. Liquid uridine triacetate formulations applied to skin before, during or after administration of 5FU reduces the severity of cutaneous 5FU toxicities, including hand-foot syndrome. Triacetin is a suitable base for topical application, optionally thickened with silicon dioxide or other compatible viscosity-enhancing agents.

5FU toxicity is mediated via two primary mechanisms. 5FU is anabolized to form intracellular fluorouridine nucleotides which cause cytotoxicity by interfering with normal uridine nucleotide metabolism. Fluorodeoxyuridine monophosphate

(FdUMP) inhibits thymidylate synthase (TS), the enzyme that produces thymidine from deoxyuridine as a precursor for DNA replication or repair. Fluorouridine triphosphate is misincorporated into RNA, causing cell death. Uridine derived from uridine triacetate can augment intracellular uridine triphosphate (UTP) concentrations; UTP competes with FUTP, reducing its incorporation into RNA and thereby reducing its cytotoxicity. Exogenous thymidine can bypass the blockade of TS by FdUMP by being directly converted to thymidine monophosphate, counteracting toxicity of 5FU or capecitabine mediated by inhibition of TS. As is the case with uridine triacetate, acetylation of thymidine improves its transport across biomembranes and through the epidermis and mucosal epithelium. In topical formulations for either mucositis or for cutaneous toxicities of 5FU, thymidine diacetate is optionally included with uridine triacetate. Relatively small amounts of thymidine diacetate are sufficient to bypass and compensate for thymidylate synthase inhibition by 5FU, versus the higher amounts of uridine triacetate required to compete with 5FU for misincorporation into RNA. The molar ratio of thymidine diacetate to uridine triacetate in formulations of the disclosure is typically in the range of 1:1 to 1:100, advantageously 1:5 to 1:20, and optimally 1:8 to 1:12. A ratio of about 1:10 is convenient.

The mouth rinse formulation can be prepared as a one-part system or a two-part system. In one embodiment, a mouth rinse formulation is prepared as solution of uridine triacetate and optionally also thymidine diacetate dissolved in triacetin or triacetin plus diacetin. This solution is mixed with an aqueous phase component at the time of use, minimizing the amount of time uridine triacetate and thymidine diacetate are in contact with water. The effective concentration range for thymidine diacetate is from 10 micromolar to 5 millimolar in the final mouthwash when ready to use, and will generally be about 10% of the concentration range of uridine triacetate. For example the mouth rinse can have a nonaqueous component (triacetin and diacetin) containing uridine triacetate and thymidine diacetate that is mixed with an aqueous phase (water plus diacetin, flavor, surfactant, or other excipients). In a two part system the concentration of uridine triacetate and thymidine diacetate before dilution with the aqueous phase could be up to, or more than, 10 times higher than in the final mouth rinse. Thus taking into account both diluted and concentrated formulations, the range of concentrations of thymidine diacetate could range from 10 micromolar to 50 millimolar, and the concentration range for of uridine triacetate is 2 to 10 times higher than that of thymidine diacetate.

Formulations according to this invention can be administered by any conventional route, for example orally, topically, by gastrostomy or nasogastric tube. Formulations according to this invention, whether containing diacetin or not, can optionally be mixed with foods, for example pudding, apple sauce, or yogurt, or optionally with pharmaceutical syrups. The invention will be better understood by reference to the following examples which illustrate but do not limit the invention described herein.

EXAMPLES Additional information regarding materials, methods, and technical details in connection with the examples may be found in the Addendum that appears after the examples.

Example 1 : Limited solubility of uridine triacetate in solvents and triglycerides

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Table 1: Solubility of Uridine Triacetate in Solvents at 20° C

Table 1 (continued)

Various known pharmaceutical excipients including triacetin, diacetin, trihexanoin, chocolate, glycerol, acetyl triethyl citrate, Tween 80, PEG 400 (polyethyleneglycol 400), and fish oils were tested to determine whether any of them as a single agent, or as a combinations in mixtures of the abovementioned excipients improved, enhanced, and/or provided better and/or higher solubility of UTA, and made it as a solution that may be delivered or administered by a standard and/or oral syringe, and/or by a softgel, and/or as a chocolate bar or roll, and/or as a gargle, and/or or as a topical application.

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Table 2

Example 2: Solubilization of uridine triacetate in triacetin

UTA (Uridine Triacetate) was dissolved in triacetin, at 100 - 115 °C at the various conditions, and evaluated at Room Temperature (22 °C) 1, 2 and 6 days later, and showed the following results:

Table 3

After dissolution in triacetin, it was then possible to formulate uridine triacetate solutions containing additional excipients. Table 4

Table 5

In view of the limited solubility of uridine triacetate in a large variety of solvents an in triglycerides, including short-chain triglycerides such as tributyrin (glycerol tributyrate), it was unexpected to discover that uridine triacetate is soluble in triacetin. Example 3: Aqueous formulations of uridine triacetate containing triacetin and diacetin

Triacetin is not freely miscible in aqueous media. Mixtures of triacetin and water in a range of ratios from 9:1 to 4:6 produce unstable emulsions, with phase separation occurring within less than 3 minutes after mixing. Similarly, triacetin containing uridine triacetate (1 gram in 1 ml triacetin) formed unstable emulsions when mixed with water, which also underwent rapid phase separation.

Table 6

Surfactants such as Tween 20, 40 or 80, which are acceptable as pharmaceutical excipients, did not enable preparation of a stable solution or emulsion. It was therefore unexpected that addition of diacetin to solutions of uridine triacetate in triacetin enabled preparation of aqueous solutions of uridine triacetate in

therapeutically adequate concentrations.

Preliminary testing shown in Table 7 showed that diacetin can overcome an incompatibility of triacetin and water, enabling preparation of aqueous solutions containing both triacetin and diacetin.

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Table 7

Aqueous formulations with uridine triacetate in vehicles comprising triacetin, diacetin and water were then prepared as follows.

All samples, mixtures and additions of components - were made at room temperature (23 °C, 16% humidity), except those of Uridine triacetate stock which was made by addition of 1 mL triacetin to 1 g of uridine triacetate in a glass vial with cap, vortexing 10 sec, and dissolving at 115 °C within 20 min, with vortexing for 10 seconds every 4 minutes. The clear, colorless stock solution prepared in this manner had a volume of 1.85 mL and a total weight of 2.16 grams, with a concentration of 0.54 g uridine triacetate per mL.

0.9 mL of clear colorless solution of uridine triacetate in triacetin (0.54 g/mL) mixed with 0.1 mL distilled water yielded 1 mL of an unstable emulsion, undergoing phase separation within 3 min. Addition of 0.5 ml diacetin resulted in 1.5 ml of a clear solution.

Similarly, mixing 0.1 mL of clear colorless solution of uridine triacetate in triacetin (0.54 g/mL) with 0.9 mL of distilled water yielded 1 mL of an unstable emulsion that also underwent phase separation within 3 minutes. Addition of 0.5 mL diacetin produced 1.5 mL of a stable clear solution.

Example 4: Aqueous mouth rinse formulations Stock solutions of 100 millimolar uridine triacetate were prepared in 1) triacetin; 2) diacetin; or 3) a 1 : 1 mixture (v/v) of triacetin and diacetin. Uridine triacetate was soluble in all three of these solvents, yielding clear colorless liquids. Uridine triacetate has a formula weight of 370.3, so an exemplary 100 millimolar solution is 370 milligrams in 10 ml of solvent. Stock solutions of 100 millimolar thymidine diacetate were prepared in 1) triacetin; 2) diacetin; or 3) a 1 : 1 mixture (v/v) of triacetin and diacetin. Thymidine diacetate was soluble in all three of these solvents, yielding clear colorless liquids. Uridine triacetate has a molecular formula weight of 326.3, so an exemplary 100 millimolar solution is 326 milligrams in 10 ml of solvent. A mixture comprising 1 part triacetin, 5 parts diacetin, and 9 parts distilled water (all parts by volume) was prepared as an aqueous diluent for the nucleoside ester stock solutions.

1 ml of the stock solution of uridine triacetate in triacetin, and 0.1 ml of the stock solution of thymidine diacetate was added to an of aliquot 8.9 ml of the aqueous diluent, yielding 10 ml of a solution containing 1 millimolar uridine triacetate and 1 millimolar thymidine diacetate. The resulting solution was stable and clear.

Stock solutions of uridine triacetate and thymidine diacetate in diacetin or a 1 : 1 mixture of triacetin and diacetin were also combined with the aqueous diluent to make aqueous formulations with final concentrations of 10 millimolar uridine triacetate and 1 millimolar thymidine diacetate. These formulations were also stable, clear solutions.

Example 5: Topical formulations

For prevention or treatment of cutaneous toxicities caused by antimetabolites or tyrosine kinase inhibitors used as anticancer agents, a suitable topical formulation should be readily absorbed into the skin, as affected cells are below the stratum corneum. Triacetin is a suitable primary excipient for topical formulations containing uridine triacetate and optionally thymidine diacetate. Additional excipients to improve pharmaceutical properties, such thickening agents such as silicon dioxide or long chain lipid molecules, waxes, glycols or other standard topical excipients.

Pharmaceutically acceptable preservatives, and penetration enhances such as transcutol, propylene glycol, or glycerol are also optional constituents.

For treatment or prevention of cutaneous toxicities caused by tyrosine kinase inhibitors, growth factor antagonists or ionizing radiation which are used for cancer treatment, topical formulations optionally contain acetate or other short chain fatty acid esters of thymidine, or in another embodiment, all four of the major

deoxyribonucleosides, deoxyadenosine, deoxycytidine, deoxyguanosine and thymidine, in quantities sufficient to reduce cutaneous toxicities of cancer treatments. Tyrosine kinase inhibitors interfere with pathways mediating effects of epithelial growth and survival factors. Inhibiting such growth factor or oncogene pathways can reduce nucleotide biosynthesis, contributing to cutaneous damage. Compositions of the disclosure counteract toxicity of tyrosine kinase inhibitors by locally replenishing intracellular nucleotides. Similarly, compositions of the disclosure containing deoxyribonucleoside acetates or other esters are useful for promoting DNA repair in skin caused by exposure to ultraviolet or solar radiation. Furthermore, compositions comprising deoxyribonucleosides or deoxynucleosde ester prodrugs such as diacetates in triacetin, optionally also with diacetin, are useful for mucositis and induced by cancer chemotherapy or radiation therapy, including but not limited to mucositis caused by fluoropyrimidines, methotrexate, tyrosine kinase inhibitors and growth factor antagonists such as antibodies that block signaling for epidermal growth factor, VEGF and other growth factors that promote mucosal healing and integrity.

Example 6: Solubility of uridine triacetate in diacetin

Uridine triacetate was dissolved in diacetin (glycerol diacetate) at 105 °C for 20 minutes, with vortexing for 10 seconds every 4 minutes. The solution was allowed to cool and stand at room temperature for 2 days Table 8

Example 7: Plasma uridine pharmacokinetics after oral administration of triacetin solutions of uridine triacetate versus solid suspension Plasma uridine concentrations were determined at various times after oral administration of three different formulations of uridine triacetate:

1. Powder suspended in 1% hydroxypropyl methylcellulose

2. 50% (w/v) uridine triacetate in triacetin

3. 50% (w/v) uridine triacetate in 1:1 triacetin: acetin Female BALB/C mice weighing approximately 20 grams were divided into 3 treatment groups of 18 mice each. Mice were fasted overnight and then uridine triacetate (2500 mg/kg in a dosing volume of 0.15 ml/10 grams body weight) was administered by oral gavage. Blood samples were collected into plasma separator tubes via the retro-orbital plexus at 6 time points: 15, 30, 60, 120, 180 and 240 minutes after uridine triacetate dosing. Blood was collected from individual mice at only 2 time points each, from subgroups of 6 mice with blood sampling at 1) 15 and 120 minutes, 2) 30 and 180 minutes, and 3) 60 and 240 minutes. Blood samples were immediately place on ice and centrifuged less than 30 minutes after collection.

Plasma samples were frozen on dry ice. For subsequent measurement of plasma uridine concentrations, plasma samples were deproteinized and analyzed with a reverse-phase LCMS assay.

The basal concentration of plasma uridine in untreated mice was approximately 1 mM. In the table below, plasma uridine concentrations ( pM) are displayed as a function of time after dosing. Table 9

Administration of the solid suspension formulation of uridine triacetate resulted in a rapid increase and subsequent decline in plasma uridine, with basal levels reached at the 240 minute time point. Administration of an equivalent dose of uridine triacetate in the triacetin and triacetin/diacetin liquid formulations resulted in maintenance of elevated plasma uridine for a longer time. Uridine uptake and conversion to intracellular uridine nucleotides is saturated at a concentration of approximately 100 micromolar.

ADDENDUM

Materials, Methods and Technical details

1. All samples, solutions, stocks and mixtures were prepared in a clear glass 2 mL vials, screw cap, certified clean for LC-MS applications, Agilent Part

Number 5182-0715, topped with screw caps, with PTFE/silicone/PTFE septa, Agilent Part Number 5185-5861.

Similarly, with the same procedures and results, samples were made in a 4 mL clear glass vials with caps, Wheaton Part Number 224892.

2. Standard laboratory pipettes, variable volume, capable to handle volumes in the range from 10 microL to 5 mL, Gilson Pipetman or equivalent, equipped with sterile disposable tips were used for samples preparation. 3. Analytical Balance, number ARBA008, with printer. Minimum sample weight label on the balance: 15 mg. Sartorius Model: BP2100. Serial Number:

60213245. Pro-Neuron label: 00558. Mettler calibration label: 1-800- METTLER, Calibrated: 020CT2014. Calibration due: OCT 2015.

4. Zerostat 3 anti-static electricity gun, Sigma-Aldrich catalog number: Z10,881-

2.

5. Dry heat-block, digital, VWR Part Number 13259-052, was used if samples needed to be heated.

6. OLIMPUS CK2 (Japan) microscope was used routinely to examine the

samples. 7. Uridine triacetate was Uridine Triacetate API, Strength: 100% (powder), Item code: D000156, Lot No.: Q000001095, Date of Manufacture 19

FEB 2002, Retest Date: MAY 2013, Bottle No.ll of 50,

Manufactured by Almac Sciences Limited (United Kingdom). 8. Glyceryl triacetate, Triacetin,

Glyceryl diacetate, Diacetin,

PEG 400, Tween 80, Tween 40, Tween 20, glycerol and other chemicals, reagents and ingredients were from Sigma- Aldrich, and of the highest purity, or equivalents from the other manufacturers/vendors.

Claims

CLAIMS What is claimed is:

1. A solution comprising uridine triacetate dissolved in a solvent, wherein the solvent comprises triacetin.

2. The solution of claim 1, wherein the concentration of uridine triacetate in the solution is from twenty percent to sixty percent by weight.

3. The solution of claim 2, wherein the concentration of uridine triacetate in the solution is from forty-six percent to sixty percent by weight.

4. The solution of claim 1, wherein the concentration of triacetin in the solution is at least twenty-eight percent by weight.

5. The solution of claim 1, further comprising thymidine diacetate.

6. The solution of claim 5, wherein the concentration of thymidine diacetate in the solution is from 10 micromolar to 50 millimolar.

7. The solution of claim 5, wherein the molar ratio of thymidine diacetate to uridine triacetate is from 1:1 to 1:100.

8 The solution of claim 7, wherein the molar ratio of thymidine diacetate to uridine diacetate is from 1:5 to 1:20.

9. The solution of claim 8, wherein the molar ratio of thymidine diacetate to uridine triacetate is from 1:8 to 1:12.

10. The solution of claim 1, further comprising diacetin.

11. The solution of claim 10, wherein the concentration of diacetin in the solution is from forty percent to sixty-seven percent by volume.

12. The solution of claim 10, further comprising water.

13. The solution of claim 12, wherein the concentration of water in the solution is up to sixty percent by volume.

14. The solution of claim 13, wherein the concentration of water in the solution is from three percent to sixty percent by volume.

15. The solution of claim 12, wherein the concentration of diacetin to water is at least 0.55 by volume.

16. The solution of claim 15, wherein the concentration of diacetin to water is from 0.55 to 10 by volume.

17. The solution of any one of claims 1-16, wherein the solution further comprises one or more additional ingredients selected from the group consisting of Tween, polyethylene glycol, acetyl triethyl citrate, glycerol trihexanoate, triethyl 2- acetylcitrate, and poly(D,L-lactide-co-glycolide).

18. The solution of claim 17, wherein the Tween is selected from the group consisting of Tween80, Tween40, and Tween20.

19. The solution of claim 17, wherein the polyethylene glycol is PEG400.

20. A uridine triacetate formulation comprising the solution of any one of claims 1-19.

21. The formulation of claim 20, further comprising one or more pharmaceutically acceptable excipients.

22. The formulation of claim 21, wherein the one or more pharmaceutically acceptable excipients are selected from the group consisting of a long-chain triglyceride, a dark chocolate, a fish oil, glycerol, and diacetyl glycerol.

23. The formulation of claim 21 or 22, wherein the formulation is a clear liquid, a slow-moving clear liquid, a semi-gel, or a slightly hazy liquid.

24. The formulation of claim 21 or 22, wherein the formulation is a solid.

25. The formulation of claim 21 or 22, encapsulated in a gel cap.

26. The formulation of claim 21 or 22, wherein the formulation is a mouthwash.

27. A method of administering uridine triacetate to a patient, comprising administering the solution of any one of claims 1-19 or the formulation of any one of claims 20-26 to the patient.

28. The method of claim 27, wherein the solution or formulation is administered orally.

29. The method of claim 27, wherein the solution or formulation is administered topically.

30. The method of claim 27, wherein the patient is a human patient.

31. A method of treating or preventing mucositis due to cancer chemotherapy or radiation therapy in a mammalian subject, comprising orally administering to the subject an effective amount of the solution of any one of claims 1-19 or the formulation of claim 23.

32 The method of claim 31, wherein the subject is a human subject.

33. A method of treating or preventing cutaneous toxicity in a mammalian subject, comprising topically administering to the subject an effective amount of the solution of any one of claims 1-19 or the formulation of claim 23 or 26.

34. The method of claim 33, wherein the cutaneous toxicity is associated with administration of 5-fluorouracil or capecitabine.

35. The method of claim 33, wherein the cutaneous toxicity is hand-foot syndrome.

36. The method of claim 33, wherein the subject is a human subject.

37. A method of treating a mitochondrial disorder in a mammalian subject, comprising administering to the subject an effective amount of the solution of any one of claims 1-19 or the formulation of any one of claims 20-26, thereby treating the mitochondrial disorder in the subject.

38. The method of claim 37, wherein the mitochondrial disorder is renal tubular acidosis.

39. The method of claim 37, wherein the solution or formulation is administered orally.

40. The method of claim 37, wherein the subject is a human subject.

41. A process for making the solution of any one of claims 1-4, comprising combining the uridine triacetate with the solvent, thereby yielding the solution.

42. A process for making the solution of any one of claims 5-19, comprising combining the uridine triacetate with the triacetin and then adding the one or more additional ingredients, thereby yielding the solution.

43. The process of claim 41 or 42, wherein the combining is done at a temperature between 100°C and 115°C.

44. The process of claim 43, further comprising cooling the solution to a temperature between 20°C and 25 °C.