CA1063937A - Composition containing n4-acylcytosine arabinosides and process for preparation thereof - Google Patents

Abstract

AND PROCESS FOR PREPARATION THEREOF

ABSTRACT OF THE DISCLOSURE
A water-soluble composition at least comprising (1) an N4-acylcytosine arabinoside and (2) at least one additive selected from (a) polyoxyethylene-bonded hydroxy fatty acid glycerin esters, (b) polyoxyethylene fatty acid esters, (c) polyoxyethylene-bonded lanolin and (d) bile acids, preferably further containing (3) at least one auxiliary additive selected from saccharides, aliphatic polyols, inorganic chlorides, inorganic bromides, inorganic sulfates and aromatic carboxylic acids or salts thereof; and a process for preparing the same.
The composition enables N4-acylcytosine arabinosides to be used in a wider range of applications.

Description

~o63~37 BACKGROUND OF l`HE INVENTION
1 Field of the Invention This invention relates to water-soluble compositions comprising N4-acylcytosine arabinosides which are useful as medicines, and to a process for preparation thereof.

2. Description of the Prior Art Cytosine arabinoside has been sold as a medicine, but its pharmaceutical effect does not last long. Attempts have, therefore, been made to acylate its N4-position. Tests on mice intraperitoneally injected with N4-acylcytosine arabinosides show that the duration of the pharmacological activity of . . ~

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, N4-acylcytosine arabinosides against intraperitoneal diseases is improved and the acylcytosine arabinosides retain resistance to the enzymes which deactivate the cytosine arabinoside.
This effect of improvement differs depending upon the number of carbon atoms in the acyl group of the N4-acylcytosine arabinosides.
It is known that the improving effect is generally higher when the number of carbon atoms in the acyl group becomes 5 or more, and is especially ou~standing when the acyl group contains 14 to 24 carbon atoms. On the other hand, however, when N4-acylcytosine arabinosides having 5 or more carbon atoms in the acyl group are used as orally administrable agents, vascular injections such as intravenous injections, and external agents such as suppositories, their effects are inferior to the effect observed in intraperitoneal injection probably because the efficiency of utilization by the living body is poor.

SUMMARY OF THE INVENTION
This invention provides a water-soluble composition comprising (1) an N4-acylcytosine arabinoside and (2) at least one additive selected from the group consisting of (a) polyoxyethylene-bonded hydroxy fatty acid glycerin esters, (b) polyoxyethylene fatty acid esters, (c) polyoxyethylene-bonded lanolin and (d) bile acids, and a process for preparation thereof. Especially preferably, the invention provides a composition of the above ingredients, which further comprises (3) at least one auxiliary additive selected from the group consisting of saccharides, aliphatic polyols, inorganic chlorides, inorganic bromides, inorganic ~, ' , s sulfates an~ aromatic carboxylic acids or salts thereof, and a process for preparation thereof.

DETAILED DESCRIPTION OF T~IE INVFNTION
N4-Acylcytosine arabinosides become more difficult to dissolve in water as ~he number of carbon atoms in the acyl group increases. Those containing 5 or more carbon atoms in the acyl group are very sparingly soluble in water, and this property becomes especially outstanding with compounds having 14 or more carbon atoms.
It is one of the objects of this invention to solubilize N4-acylcytosine arabinosides by adding specified additives.
Another object of this invention is to increase the rate of biological utilization of N4-acylcytosine arabinosides.
Generally, when medicines not appreciably soluble under standard conditions are used together with surface active agents, the rate of their dissolving, their dispersibility in the blood and the angle of their contact with the skin or mucous membrane OT the wall of the alimentary canal increase, but the rate of their absorption from the skin, mucous membrane or the wall of the alimentary canal decreases, and their concentration in the blood is reduced by the metabolism or excretion through the kidneys, etc. It has been believed, therefore, that their effect against the peritoneal lesions by oral administration or intravenous injection is inferior to intraperitoneal injection that directly acts on the lesions.
The present inventor has now found that compositions

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~063937 of N4-acylcytosinc arabinosidcs containing specified additives become water-soluble, and their rate of biological utilization increases even when they are used as peroral agents, vascular injections such as intravenous injections and external agents, The present invention is directed to a ~later-soluble composi-tion at least comprising (1) an N4-acylcytosine arabinoside and (2) at least one additive selected from the group consisting of (a) polyoxyethylene-bonded hydroxy fatty acid glycerin esters, (b) polyoxyethylene fatty acid esters, (c) polyoxyethylene-bonded lanoline and (d) bile acids, and a process for preparation thereof. Preferably, the invention provides a water-soluble composition comprising (1) an N4-acylcytosyne arabinoside, (2) at least one additive selected from the group consisting of (a) polyoxyethylene-bonded hydroxy fatty acid glycerin esters, ~b) polyoxyethylene fatty acid esters, (c) polyoxyethylene-bonded lanolin and ~d) bile acids, and (3) at least one auxiliary additive selected from the group consisting of saccharides, aliphatic polyols, inorganic chlorides, inorganic bromides, inorganic sulfates and aromatic carboxylic acids or their salts, and a process for preparation thereof.
The composition comprising an N4-acylcytosine arabinoside and the above-mentioned additive is sold as a solid, and can be used after adding an aqueous solution of an auxiliary additive prior to use. The composition which further contains the auxiliary additive in addition to the above-described additive can be formulated preferably into a solid. The solid can very simply form a stable liquid by merely mixing it with water prior , - 3 ~-to use. Such compositions achieve the objccts and advantages of the present invention The composition containing the N4-acylcytosine arabinoside and the additive must be heated to 60 - 100C when it is dissolved in an aqueous solution of an auxiliary additive prior to use.
However, the composition which contains the auxiliary additive in advance readily dissolves in water at room temperature, and is more preferred.
The additive used in this invention is at least one compound selected from the group consisting of (a) polyoxyethylene-bonded hydroxy fatty acid glycerin esters, (b) polyoxyethylene fatty acid esters,(c) polyoxyethylene-bonded lanolin and (d) bile acids. When the additive contains a polyoxyethylene group (in the case of (a), (b) and (c)), it is preferred that 10 to 200 moles, preferably 20 to 100 moles, on an average, of oxyethylene be polymerized at the polyoxyethylene portion.
When the additive contains a fatty acid residue (in the case of (b)) or a hydroxy fatty acid residue (in the case of (a)), fatty acid residues or hydroxy fatty acid residues containing 10 to 20 carbon atoms (e.g., capric acid, hydroxycapric acid, stearic acid, hydroxystearic acid, eicosanoic acid, hydroxy-eicosanoic acid, etc.) are preferred.
Of the additives used in the present invention, bile acids (d) and glycerin esters of hydroxy fatty acids containing 10 to 20 carbon atoms (e.g., hydroxycapric acid, hydroxylauric acid, hydroxymyristic acid, hydroxypalmitic acid, hydroxymargaric acid, hydroxystearic acid, hydroxyeicosanoic acid, ricinoleic

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acid, etc.~ to which polyoxycthylene having an avcrage degrec of polymerization of 10 to 200 moles, prcferably 40 to 100 moles bonds, are especifically preferred. Of the latter, hydrogenated castor oil having added thereto polyoxyethylene having an average degree of polymerization of 40 to 100 moles and a glycerin ester of hydroxystearic acid having bonded thereto polyoxyethylene having an average degree of polymerization of 40 to 100 moles are more preferred.
The bile acids denote bile acids and their salts, and include, for example, such bile acids as deoxycholic acid, dehydrocholic acid, cholic acid, lithocholic acid, chenode-oxycholic acid, lagodeoxycholic acid, hyocholic acid and phocaecholic acid, and salts of these bile acids. Of these, the deoxycholic acid and dehydrocholic acid, and salts of these are especially preferred. As the salts of bile acids, alkali metal salts and ammonium salts are preferred. The sodium salts, potassium salts, ammonium salts, trimethylammonium salts and procaine salts are more preferred. The sodium salts are especially superior. Especially preferred bile acids are sodium deoxycholate and sodium dehydrocholate.
Accordingly, preferred additives are sodium deoxycholate, sodium dehydrocholate, hydrogenated castor oil having bonded thereto oxyethylene with an average degree of polymerization of 40 to 100 moles, and a glycerin ester of hydroxy stearic acid having bonded thereto oxyethylene having an average degree of polymerization of 40 to 100 moles. The hydrogenated castor oil having bonded thereto the oxyethylene is most preferred.

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10~;3937 The xuxiliary ad~itive is at least one compound selerted from sacchari~lcs, aliphatic polyols, inorganic chlorides, irlorgallic bromidcs, inorganic sulfates and aromat~ic carboxylic acids or their salts.
Preferred saccharides are monosaccharides such as ribose, arabinose, glucose, fructose, sorbitol, mannitol, xylose, and galactose, disaccharides such as lactose and saccharose and in oral administration only, polysaccharides such as cellulose.
Glucose is most preferred.
Examples of the aliphatic polyols are glycerol, propylene glycol and polyethylene glycol. The glycerol and propylene glycol are especially preferred.
Preferred inorganic chlorides or bromides are chlorides of alkali metals or alkaline earth metals, and bromides of alkali metals or alkaline earth metals. Especially preferred chlorides are NaCl, CaC12 and MgC12, and next comes KCl. On the other hand, MgSO4 is especially preferred as the inorganic sulfate.
The aromatic carboxylic acids are, for example, ben~oic acid and salicyclic acid, and are preferably used as alkali metal salts, alkaline earth metal salts and ammonium salts. The sodium salts are especially preferred, and sodium salicylate is the best among them.
The amount of the additive or the auxiliary additive is preferably 0.1 to 20 parts by weight per part by weight of the N4-acylcytosine arabinoside. If the amount is less than 0.1 part by weight, the effect desired is not obtained. On the other hand, amounts exceeding 20 parts by weight do not produce any special result, and are not economical because the concent-.
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, : , , ': ' ~063937 ration of the N4-acylcytosine arabinoside decreases.
The co~position containing the N4-acylcytosine arabinoside and the additive can be prepared by uniformly mixing these ingredients. In order to mix them uniformly, it is the general practice tG dissolve them in a solvent, which solvent is then evaporated off from the solution. This results in the formation of a composition consisting of the N4-acylcytosine arabinoside and the additive. The composition consisting of the N4-acylcytosine arabinoside and the additive is sold as a solid, and can be used after addition of an aqueous solution of an auxiliary additive prior to use.
The composition consisting of the N4-acylcytosine arabinoside, the additive and the auxiliary additive can be prepared by uniformly mixing these three ingredients.
Preferably, it is prepared by adding an aqueous solution of the auxiliary additive to a composition consisting of the N4-acylcytosine arabinoside and the additive. When water is evaporated after forming the solution, the composition becomes solid and is easy to transport. Lyophilization, however, is especially preferred to render this composition solid.
Such a solid composition very simply becomes a stable liquid by merely mixing it with water prior to use, and can achieve the objects and advantages of the present invention.
In other words, in order to solubilize the N4-acylcytosine arabinoside so as to meet the object of this invention, it is only sufficient to mix the N4-acylcytosine arabinoside and the additive, preferably further adding the auxiliary additive.

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~,' . , For uniform mixing, it is the gencral practice to dissolve the N4-acylcytosine arabinoside and the additive in a solvent, followed by evaporating the solvent from the solution.
Preferably the auxiliary additive and water, or an aqueous solution of the auxiliary additive, is added to the composition consisting of the N4-acylcytosine arabinoside and the additive, and the mixture is heated to form a solution, followed, if desired, by evaporating the water from the solution.
In dissolving the N4-acylcytosine arabinoside and the additive, the amount of the solvent used is not particularly critical, but generally, ranges from 10 to 1,000 parts by weight per part by weight of the N4-acylcytosine arabinoside.
The amount of water used together with the auxiliary additive is neither restricted. Generally, the amount is preferably S0 to 1,000 parts by weight per part by weight of the N4-acylcytosine arabinoside.
In uniformly mixing the N4-acylcytosine arabinoside and the additive and preferably further with the auxiliary additive, the pressure, temperature and time conditions shown below can be used. The N4-acylcytosine arabinoside and additive are dissolved in a solvent for these materials at a pressure of 1 to 2 atms. and at a temperature of -20C to the boiling point of the solvent, preferably 40 to 100C ~the boiling point when the boiling point is below 100C) for 1 minute to 20 hours, preferably 5 minutes to 2 hours. Then, the solvent is evaporated at a pressure of 0.001 to 1 atm. and at a tempe~ature of 0C to the boiling point of the solvent, preferably 40 to 80C (the ~ ., " . . , . -:
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boiling point ~hen the boiling point is below 80C) for ~ minutes to 20 hours, prefcrably 10 minutes to 4 hours. If required, the mixture is then dried at a pressure of 0.001 to 0.5 atms.
and at a temperature of 10 to 30C for 4 to 100 hours.
Pref-rably, water or both the auxiliary additive and water, or an aqueous solution of the auxiliary additive, is added to the water-soluble solid mentioned above (consisting of the N4-acylcytosine arablnoside and the additive), and the mixture is heated at 1 to 1.5 atms. and at 60 to 120C for 1 minute to 4 hours to form a solution. When the auxiliary additive is not added, the solution obtained be not allowed to cool spontaneously, but rapidly cooled to -40C to +20C with flowing water, ice water, dry ice-acetone, etc. This will increase the solubllity of the solid further. Where the auxiliary additive is added, the ingredients dissolve sufficiently without this rapid cooling operation.
In order to prepare an aqueous solution of the N4-acylcytosine arabinoside containing an organic solvent, an aqueous solution of the N4-acylcytosine arabinoside not at all containing the organic solvent is first prepared, and the organic solvent is then added to the aqueous solution.
Alternatively, an aqueous solution containing the organic solvent is added to the N4-acylcytosine arabinoside, and the mixture is heated, followed by rapidly cooling the resulting solution. Another alternative, which is sometimes difficult when the amount of the organic solvent to be added is small, is to add the organic solvent to the N4-acylcytosine arabinoside and additive, heat the mixture, and add water to an aqueous : 9 ,~ .
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s ~ s, s solution of the auxiliary additive either dircctly or after cooling the mi~ture to room temperature, to thereby form an aqueous solution of the N4-acylcytosine arabinoside containing the organic solvent. Another possible method is to add an aqueous sol~tion of the additive or both the additive and the auxiliary additive to an organic solvent containing the N4-acylcytosine arabinoside. It would also be possible to add an aqueous solution containing the additive, or both the additive and the auxiliary additive, and an organic solvent to the N4-acylcytosine arabinoside.
Examples of the solvent capable of dissolving the N4-acylcytosine arabinoside and the additive include ketones such as acetone and methyl ethyl ketone, esters such as ethyl acetate and butyl acetate, aliphatic ethers such as diethyl ether and methylethyl ether, cyclic ethers such as tetrahydTofuran, tetrahydropyran and dioxane, amides such as dimethyl acetamide, dimethyl formamide and diethyl acetamide, sulfoxides such as dimethyl sulfoxide, alcohols such as methanol, ethanol, n-propanol and isopropanol, bases such as pyridine and triethanolamines, and acids such as formic acid and acetic acid. Of these, the ketones, esters, cylic ethers, aliphatic ethers, amides and sulfoxides are preferred because they do not decompose the N4-acylcytosine arabinoside. The ketones, esters, aliphatic ethers, cyclic monoethers and alcohols are preferred because of their ease of evaporation. The ketones, amides and ethanol are preferred because of their low toxicity. Accordingly, the ketones are most preferred because of their superior stability ,. , .
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and evaporability and low toxicity. Since the cyclic monoethers are superior in stabi.lity, evaporability and solubility, they are as preferred as the ketones if they are completely evaporated after use. Since ethanol has good evaporability and solubility and low toxicity, it is as preferred as the ketones if the time of its contact with the N4-acylcytosine arabinoside is shortened.
It is time-consuming to evaporate the amides and the sulfoxides completely, but otherwise, they are preferred in the next place because of their superior stability and solubility and low toxicity.
The composition of this invention can be formulated into internal preparations (orally administrable preparations) such as tablets, trouches, buccal agents, chewable preparations, capsules, cachets, powders, granules, pills, extracts, fluid extracts, solutions, elixirs, spirit-incorporated preparations, syrups, lemonades, aromatic water preparations, emulsions or suspensions by adding, if required, vehicles, binders, disintegrants, coating agents, solvents, correctives, pH adjusters, thickening agents, stabilizers, wetting agents, defoamers, lubricants, colorants, color inhibitors, moisture-proof agents, flavoring agents, etc. The composition can also be formulated into externally applicable preparations such as ointments, creams, pastes, liniments, plasters, ophthalmic ointments, suppositories (through the anus, cavity or urethra), lotions, jellies, liquids (eye drops, nasal drops, lavages and baths), dusts (spray and powder), tablets, aerosols and the like by adding base agents, thickening agents, defoamers, stabilizers, flavoring agents, ~063937 colorants, solverlts> isotonicity-imparting agents, buffers or pain-reducing or -eli~inatillg agents. If further required, the composition can be formulated into injectables such as water preparations or oil preparations by adding pain-reducing or -eliminating agents, isotonicity-imparting agents, buffers, extenders or solvents. Or it can be formed into inhalants in aerosol form by adding solvents.
N4-Acylcytosine arabinosides having 14 to 24 carbon atoms in the acyl group at the N4-position are especially preferred because they exhibit high pharmacological actions in accordance with the present invention. Those in which the acyl group is a saturated or unsaturated and substituted or unsubstituted acyl group selected from myristoyl, palmitoyl, margaroyl, stearoyl, nonadecanoyl, arachidoyl, heneicosanoyl, behenoyl, tricosanoyl, lignoceroyl, oleoyl, 5-methyl nonadecanoyl, 2-chlorostearoyl, 18-hydroxystearoyl and 2-mercaptostearoyl exhibit favorable effects. Of these, N4-stearoylcytosine arabinoside and N4-behenoylcytosine arabinoside show especially favorable effects.
The N4-acylcytosine arabinosides having 14 to 24 carbon atoms in the acyl group are quite insoluble in water (soluble in a concentration of less than 0.00001% by weight), but become soluble in water in an amount of 0.02 to 4% by weight by adding 0.1 to 20% by weight of the specific additive and preferably also the same amount of the auxiliary additive.
Since the desirable concentration of the arabinoside in injectables for clinical purposes is 0.01 to 1% by weight . , .

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, ~ , ~ 063937 (preferably ad~inistered in a dosage of 0.1 to 1,000 mg, preferably 1 to 100 ~ng, per day for an adult), an aqueous solution of the arabinoside prepared in this invention has a sufficiently high concentration for use as injectables.
All of the additives used to form the N4-acylcytosine arabinoside compositions in this invention are known and commer-cially available.
The N -acylcytosine arabinosides are obtained, for example, by reacting cytosine arabinoside with acid anhydrides in the presence o water. For example, N4-behenoylcytosine arabinoside can be obtained in the following manner.
Cytosine arabinoside (1.23 millimoles) is dissolved in 2 ml of water, and 30 ml of dioxane and 2.47 millimoles of behenic anhydride are further added. The mixture is heated to 80C to dissolve the precipitate. After stirring at 80C for

5 hours, the reaction mixture is allowed to cool, and the precipitate is collected by filtration. The precipitate is thoroughly washed with water, and dried. To the dried precipitate is added n-hexane, and the mixture heated under reflux.
The product is cooled and collected by filtration. The product is then washed with benzene and then with toluene.
Recrystallization from ethyl acetate affords N4-behenoylcytosine arabinoside (AS-22) in a yield of 82.5%.
Other N4-acylcytosine arabinosides are synthesized by using acid anhydrides corresponding to the acyl groups of the desired products instead of behenic anhydride.
The following ~xamples illustrate the present invention .

in greater detail.
The determination of the pharmacological activity of the compounds of this invention is performed using mice injected with L-1210 leukemic cells. The L-1210 mouse leukemia is being employed as a standard of judging anticancer activity both by Cancer Institute, National Institute of Healthy of U. S. A. and by Cancer Chemotherapy Center, Japanese Foundation for Cancer Research on the ground that among perimental cancers, L-1210 leukemia on mice most predicts pharmacological effects of drug against cancer on humans.
Specifically, the test is conducted as follows:
An N4-acylcytosine arabinoside is administered to groups of mice each consisting of 10 mice of the CDFl line intraperitoneally injected with 106, for each mouse, of L-1210 leukemic cells.
The average survival time (T) of the mice in the experimental groups and the average survival time (C)of the mice in the control groups are determined, and the pharmacological effect of the N4-acylcytosine is expressed by the percentage of T based on C (T/C ~).
The acute toxicity of the N4-acylcytosine arabinoside is expressed by the dosage, per kilogram of body weight of mouse, of the N4-acylcytosine arabinoside which causes five out of 10 male mice of the CDFl line as one group to die. This is indicated as LD50 mg/kg.
The present invention will be described in more detail by the following examples.
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Example 1 One gram of N4-behenoylcytosine arabinoside and each of the additives shown in Table 1 in the amounts indicated were added to 100 g of dioxane. The mixture was heated at 1 atm. and at 80C for 10 minutes, and the dioxane was evaporated at 0.1 atm. and at 60C for 4 hours.
The residue and each of the auxiliary additives shown in Table 2 (the numbers correspond to those in Table 1) in the amounts indicated were added to 200 g of water. The mixture was heated at 95C and at 1 atm. for 20 minutes with stirring, and then çooled in ice water, followed by lyophilizing.
The compositions shown in Table 3 (the numbers also correspond to those in Tables 1 and 2) were obtained as white amorphous powders ~the composition Nos. 2 and 6 were white semi-fluids) in the yields indicated.

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~', , Table No. Additive Weight (g) 1 HCO-10 [polyoxyethylene(10) hydrogenated 0.1 castor oil]

3 HCO-60 [polyoxyethylene(6o) hydrogenated castor oil] 0.

6 HCO-200 [polyoxyethylene (200) hydrogenated castor oil] 0.1

7 HCO-200 20

8 Polyoxyethylene ~60)-glycerin 0.1 trihydroxycaprate

9 Polyoxyethylene ~60)-glycerin trihydroxycaprate 20 Polyoxyethylene ~60)-glycerin dihydroxyarachidate 0.1 11 Polyoxyethylene ~60)-glycerin dihydroxyarachidate 20 12 Polyoxyethylene ~60).glycerin trihydroxystearate/glycerin tristearate mixture (3:1) 0.1 13 Polyoxyethylene (60)-glycerine trihydroxystearate/glycerine tristearate mixture ~3:1) 20 14 HCO-60/sodium deoxycholate ~1:1) 0.2 lS HCO-60/sodium deoxycholate (70:1) 7.1 16 HCO-60/sodium d.eoxycholate (35:1) 7.2 ; 17 HCO-60/potassium deoxycholate (25:1) 5.2 18 Deoxycholic acid 0.1 . .

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10~;3937 lahle 1 (cont_n ed) No. Additive Weight ~g~
19 Deoxycholic acid 20 Sodium deoxycholate 0.1 21 Sodium deoxycholate 20 22 Potassium deoxycholate 0.1 23 Potassium deoxycholate 20 24 Dehydrocholic acid 0.1 Dehydrocholic acid 20 26 Sodium cholate 0.1 27 Sodium cholate 20 28 Sodium lithocholate 0.1 29 Sodium lithocholate 20 Chenodeoxycholic acid 0.1 31 Chenodeoxycholic acid 20 32 Ursodeoxycholic acid 0.1 33 Ursodeoxycholic acid 20 34 Sodium hyodeoxycholate 0.1 Sodium hyodeoxycholate 20 36 Sodium lagodeoxycholate 0.1 37 Sodium lagodeoxycholate 20 38 Sodium hyocholate 0.1 39 Sodium hyocholate 20 Sodium phocaecholate 0.1 41 Sodium phocaecholate 20 42 Ammonium deoxycholate 0.1 43 Ammonium deoxycholate 20 44 Trimethylammonium deoxycholate 0.1 - 17 - . .

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' ~063937 Tablc 1 (continucd)_ No. Additive Weight ~g) Trimethylammonium deoxycholate 20 46 Procaine deoxycholate 0.1 47 Procaine deoxycholate 20 HCO-60/sodium deoxycholate ~35:1) 7.2 56 HCO-60/sodium deoxycholate (35:1) 7.2 57 HCO-60/sodium deoxycholate (35:1) 7.2 58 HCO-60/sodium deoxycholate (35:1) 7.2 59 HCO-60/sodium deoxycholate (35:1) 7.2 HCO-60/sodium deoxycholate (35:1) 7.2 61 HCO-60/sodium deoxycholate (35:1) 7.2 62 HCO-60/sodium deoxycholate (35:1) 7.2 63 HCO-60/sodium deoxycholate (35:1) 7.2 64 HCO-60/sodium deoxycholate (35:1) 7.2 HCO-60/sodium deoxycholate (35:1) 7.2 66 HCO-60/sodium dehydrocholate (35:1) 7.2 67 HCO-60/sodium dehydrocholate (35:1) 7.2 68 HCO-60/sodium dehydrocholate (35:1) 7.2 69 HCO-60/sodium dehydrocholate (35:1) 7.2 HCO-60/sodium dehydrocholate (35:1) 7.2 ,, : - 18 -~' :
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~063937 Ta)lc 1 (continucd) No. Additive Weight 71 HCO-60/sodium dehydrocholate (35:1) 7.2 72 HCO-60/sodium dehydrocholate (35:1) 7.2 73 HCO-60/sodium dehydrocholate (35:1) 7.2 74 HCO-~0/sodium dehydrocholate (35:1) 7.2 HCO-60/sodium dehydrocholate (35:1) 7.2 76 HCO-60/sodium dehydrocholate (35:1) 7.2 Table 2 No. Auxiliary ~dditive Weight (g~ -1 Glycerol 20 2 Glycerol 0.1 3 Glucose 5 4 Glucose . 5 Glucose 5 6 Propylene glycol 20 7 Propylene glycol 0.1 8 Ribose 20 9 Ribose 0.1 Arabinose 20

11 Arabinose . 0.1

12 Fructose 20

13 Fructose 0.1

14 Sorbitol 20 Sorbitol 0.1 16 Mannitol 20 17 Mannitol 0.1 18 Lactose 20 19 Lactose 0.1 Saccharose 20 21 Saccharose 0.1 22 NaCl . 20 23 NaCl 0.1 24 KCl 20 ' ";

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KCl 0.1 26 CaC12 20 27 CaCl~ 0.1 28 MgC12 . 20 29 MgC12 0.1 Benzoic acid 20 31 Benzoic acid - 0.1 32 Sodium benzoate 20 33 Sodium benzoate 0.1 34 Potassium benzoate 20 Potassium benzoate 0.1 36 Salicylic acid 20 37 Salicyclic acid 0.1 38 Sodium salicylate 20 39 Sodium salicylate 0.1 Potassium salicylate 20 41 Potassium salicylate 0.1 42 Mixture of glucose and CaC12(10:1) 5.5 43 Mixture of glucose and MgC12(10:1) 5.5 44 Mixture of glucose and sodium benzoate (50:1) 5.1 Mixture of glucose and sodium salicylate (50:1) 5.1 46 Mixture of NaCl and CaC12 (1:1) 47 Mixture of NaCl and MgC12 (1:1) 48 Mixture of glucose and CaC12 (10:1) 5.5 49 Mixture of glucose and MgC12 (10:1) 5.5 Mixture of glucose and sodium salicylate (50:1) 5.1 ~, .

Tablc 2_ (con_i ued) _ No. AuYiliary Acklitivc .~eight ~g~
51 CaC12 52 MgC12 53 NaCl 54 KCl Mixture of glucose and CaC12 ~10:1) 5.5 56 Mixture of glucose and MgC12 ~10:1) 5.5 57 Mixture of gl~cose and sodium benzoate (50:1) 5.1 58 Mixture of glucose and sodium salicylate (50:1) 5.1 59 Glucose 5 NaCl 61 CaC12 62 MgC12 63 Sodium salicylate 0.1 64 Fructose 5 Lactose 5 66 Mixture of glucose and CaC12 (10:1) 5.5 67 Mixture of glucose and MgC12 ~10:1) 5.5 68 Mixture of glucose and sodium benzoate ~50:1) 5.1 69 Mixture of glucose and sodium salicylate ~50:1) 5.1 Glucose 5 71 NaCl 72 CaC12 73 MgC12 74 Sodium salicylate 0.1 Fructose 5 76 Lactose 5 Table 3 Yield N Composition %

1 Be-C:HCO-lO:Gly(1:01:20) 98 2 Be-C:HC0-lO:Gly (1:20:0.1) 98 3 Be-C:HCO-60:Glu (1:0.1:5) 98 4 Be-C:HCO-60:Glu (1 : 5 : 5) 98 Be-C:HCO-60:Glu (1:20:5) 98 6 Be-C:HCO-200:Pro (1:0.1:20) 98 7 Be-C:HCO-200:Pro (1:20:0.1) 98 8 Be-C:Cap-60:Rib(1:0.1:20) 97 9 Be-C:Cap-60:Rib (1:20:0.1) 97 Be-C:Ara-60:Ara(1:0.1:20) 97 11 Be-C:Ara-60:Ara(1:20:0.1) 97 12 Be-C:Ste-60:Fru (1:0.1:20) 97 13 Be-C:Ste-60:Fru(1:20:0.1) 97 14 Be-C:HCO-60:DeoxNa:Sor(1:0.1:0.1:20) 97 Be-C:HCO-60:DeoxNa:Sor(1:7:0.1:0.1) 97 16 Be-C:HCO-60:DeoxNa:Man(1:7:0,2:20) 97 17 Be-C:HCO-60:DeoxNa:Man(1:7:0.2:0.1) 97 18 Be-C:DeoxH:Lac (l:G.1:20) 97 19 Be-C:DeoxH:Lac (1:20:0.1) 97 Be-C:DeoxNa:Sac(1:0.1:20) 97 21 Be-C:DeoxNa:Sac(1:20:0.1) 97 22 Be-C:DeoxK:NaCl(1:0.1:20) 97 ~063937 Table 3 (continued) No. Composition Yield 23 Be-C:DeoxK:NaCl (1:20:0.1) 97 24 Be-C:DehH:KCl (1:0.1:20) 97 Be-C:DehH:KCl (1;20:0.1) 97 26 Be-C:CNa:CaCl2(1:0.1:20) 97 27 Be-C:CNa:CaC12(1:20:0.1) 97 28 Be-C:I,iNa:MgC12(1:0.1:20) 97 29 Be-C:LiNa:MgCl2(1:20:0.1) 97 Be-C:CheH:BenH(1:0.1:20) 98 31 Be-C:CheH:BenH(1:20:0.1) 98 32 Be-C:UruH:BenNa(1:0.1:20) 98 33 Be-C:UruH:BenNa(1:20:0.1) 98 34 Be-C:HyodNa:BenK(1:0.1:20) 98 Be-C:HyodNa:BenK(1:20:0.1) 98 36 Be-C:LagodNa:SalH(1:0.1:20) 98 37 Be-C:La~odNa:SalH(1:20:0.1) 98 38 Be-C:HyoNa:SalNa(1:0.1:20) 98 39 Be-C:HyoNa:SalNa(1:20:0.1) 98 Be-C:PhoNa:SalK (1:0.1:20) 98 41 Be-C:PhoNa:SalK (1:20:0.1) 98 42 Be-C:DeoxNH4:Glu:CaCi2 (1:0.1:5:0.5) 97 43 Be-C:DeoxNH4:Glu:MgC12 (1:20:5:0.5) 97 44 Be-C:DeoxT:Glu:BenNa (1:0.1:5:0.1) 98 Be-C:DeoxT:Glu:SalNa (1:20:5:0.1) 98 46 Be-C:DeoxPr:NaCl:CaC12 (1:0.1:0.5:0.5)97 Table 3 (continue~) No. Composition Yield 47 Be-C:DeoxPr:NaCl:~lgC12(1:20:0.5:0.5) 97 48 Be-C:HCO-60:Glu:CaC12(1:5:5:0.5) 97 49 Be-C:HCO-60:Glu:~lgC12(1:5:5:0.5) 97 Be-C:HCO-60:Glu:SalNa(1:5:5:0.1) 98 51 Be-C:HCO-60:CaC12 (1:5:1) 97 52 Be-C:HCO-60:MgC12 (1:5:1) 97 53 Be-C:HCO-60:NaCl (1:5:1) 97 54 Be-C:HCO-60:KCl (1:5:1) 97 Be-C:HCO-60:DeoxNa:Glu:CaC12 (1:7:0.2:5:0.5) 97 56 Be-C:HCO-60:DeoxNa:Glu:MgC12 (1:7:0.2:5:0.5) 97 57 Be-C:HCO-60:DeoxNa:Glu:BenNa (1:7:0.2:5:0.1) 98 58 Be-C:HCO-60:DeoxNa:Glu:SalNa (1:7:0.2:5~0.1) 98 59 Be-C:HCO-60:DeoxNa:Glu (1:7:0.2:5) 97 Be-C:HCO-60:DeoxNa:NaCl(1:7:0.2:1) 97 61 Be-C:HCO-60:DeoxNa:CaC12(1:7:0.2:1) 97 62 Be-C:HCO-60:DeoxNa:MgC12(1:7:0.2:1) 97 63 Be-C:HCO-60:DeoxNa:SalNa(1:7:0.2:0.1) 98 64 Be-C:HCO-60:DeoxNa:Fru(1:7:0.2:5) 97 Be-C:HCO-60:DeoxNa:Lac(1:7:0.2:5) 97 66 Be-C:HCO-60:DehNa:Glu:CaC12 (1:7:0.2:5:0.5) 97 67 Be-C:HCO-60:DehNa:Glu:MgC12 (1:7:0.2:5:0.5) 97 , . , - .

, Table 3 (continued) No. Composition Yield %
68 Be-C:HCO-60:DehNa:Clu:BenNa (1:7:0.2:5:0.1) 98 ~ 69 Be-C:HCO-60:DehNa:Glu:SalNa ; (1:7:0.2:5:0.1) 98 Be-C:HCO-60:DehNa:Glu(1:7:0.2:5)97 71 Be-C:HCO-60:DehNa:NaCl (1:7:0.2:1) 97 72 Be-C:HCO-60:DehNa:CaC12(1:7:0.2:1) 97 73 Be-C:HCO-60:DehNa:MgC12(1:7:0.2:1) 97 74 Be-C:HCO-60:DehNa:SalNa(1:7:0.2:0.1) 98 Be-C:HCO-60:DehNa:Fru (1:7:0.2:5) 97 76 Be-C:HCO-60:DehNa:Lac (1:7:0.2:5) 97 The abbreviations used in Tables 1, 2 and 3 and else-where have the following meanings.
Be-C: N4-Behenoylcytosine arabinoside HCO-10: Hydrogenated castor oil having bonded thereto polyoxyethylene with an average degree of polymerization of 10 HC0-60: Hydrogenated castor oil having bonded thereto polyoxyethylene with an average degree of polymerization of 60 HC0-200: Hydrogenated castor oil having bonded thereto polyoxyethylene with an average degree of polymerization of 200 Cap-60: Glycerin trihydroxycaprate having bonded thereto polyoxyethylene with an average degree of polymerization of 60 : Ara-60: Glycerin dihydroxyarachidate having bonded thereto polyoxyethylene with an average degree of polymerization of 60 Ste-60: Glycerin trihydroxystearate having bonded thereto polyoxyethylene with an average degree of polymerization of 60 DeoxNa: Sodium deoxycholate DeoxH: Deoxycholic acid DeoxK: Potassium deoxycholate DehH: Dehydrocholic acid DehNa: Sodium dehydrocholate CNa: Sodium cholate .

LiNa: Sodium lithocholate CheH: Chenodeoxycholic acid UruH: Ursodeoxycholic acid HyodNa: Sodium hyodeoxycholate LagodNa: Sodium lagodeoxycholate HyoNa: Sodium hyocholate PhoNa: Sodium Phocaecholate DeoxNH4: Ammonium deoxycholate DeoxT: Trimethylammonium deoxycholate DeoxPr: Procaine deoxycholate Gly: Glycerin Glu: Glucose Pro: Propylene glycol Rib: Ribose Ara: Arabinose Fru: Fructose Sor: Sorbitol Man: Mannitol Lac: Lactose Sac: . Saccharose BenH: Benzoic acid BenNa: Sodium benzoate Benk: Potassium benzoate SalH: Salicylic acid SalNa: Sodium salicylate Salk: Potassium salicylate In or~er to examine the anticancer activity of the compositions of this invention and N4-behenoylcytosine arabino-side alone in intravenous injection, groups of mice each con-sisting of 10 male mice of the CDFl line injected with 106, per mouse, of L-1210 leukemic cells were intravenously injected with an aqueous solution containing 100 mg, calculated as the N4-behenoylcytosine-arabinoside, of each of the compositions or 100 mg of N4-behenoylcytosine arabinoside alone once on the 2nd and 6th days. The average survival time of the mice (T) was determined, and divided by the average survival time (C) of control groups not administered with the drugs at all to obtain T/C % as shown in Table 4 below.
The toxicity of each of the compositions of the invention and N4-behenoylcytosine arabinoside in intravenous injection was expressed by the dosage, per kilogram of body weight of each mouse, of the N4-behenoylcytosine arabinoside contained in each composition which killed five out of 10 male mice of the CDFl line as one group to obtain LDso mg/kg as shown in Table 4.

Table 4 Composition No. Anticancer Activity Toxicity ( T/C %)(LD50 mg/kg) .

,, , - ~ , 1~)63937 Tabl~ 4rcontinued~
- Composition No. Anticancer Activity Toxic ~
T C (LD50 mg g) 11 ' 300 400 : 17 380 400 : 31 300 400 ~; - 30 -: ~., . ,., ,.,: .. :

Table 4 (continued) Composition No. Anticancer Activity Toxicity (T/C ~)(LD50 mg/kg~

34 3pO 400 41 . 300 400 , . . .
:' ' " ~-:' .

.
.
~ . .

Table 4 (continued) Composition No. Anticancer Activity Toxicity (T/C %)(LD50 mg/ g) ' 380 400 N -Behenoyl*

Note: * N4-Behenoylcytosine arabinoside suspended in a 0.5 ~ aqueous solution of methyl cellulose It can be scen from Table 4 that while the anticancer activity (T/C %) of N4-behenoylcytosine arabinoside alone in intravenous injection was 150%, the activity of the composition of this invention showed an increase to 300 to 380~. -Example 2 One gram each of the N4-acylcytosine arabinosides shown in Table 5 and 7 g of HC0-60 were added to 1 kg of acetone.
The mixture was heated at 55C and at 1 atm. for 10 minutes, and then the acetone was evaporated from the solution by heating at 40C and at 0.1 atm. for 4 hours.
The residue and 5 g of glucose were added to 500 g of water, and the mixture was heated with stirring at 95C and at 1 atm.
for 20 minutes and then cooled in ice water. It was then lyophilized. Thus, the compositions shown in Table 6 (the numbers correspond to those in Table 5) were obtained as white amorphous powders in the yields shown in Table 6.
The anticancer activity (T/C %) of each of the compositions obtained and N4-acylcytosine arabinosides alone in a 0.5% aqueous solution of methyl cellulose in intravenous injection (100 mg/kg x two times), and their toxicity [LD50 (mg/kg)] were determined in the same way as in Example 1, and the results are shown in Table 7.

, ' ' - ' .

, Table 5 N N4-Acylcytosine arabinoside 77 N4-Nonadecanoylcytosine arabinoside 78 N4-Arachidoylcytosine arabinoside 79 N4-Heneicosanoylcytosine arabinoside N4-Tricosanoylcytosine arabinoside 81 N4-Lignoceroylcytosine arabinoside 82 N4-(5-Methylnonadecanoyl)cytosine arabinoside Table 6 No. Composition Yield 77 N4-Nonadecanoyl CA:HC0-60:Glu(1:7:5) 97 78 N4-Arachidoyl CA:HC0-60:Glu (1:7:5) 97 79 N4-Heneicosanoyl CA:HCO-60:Glu (1:7:5) 97 N4-Tricosanoyl CA:HCO-60:Glu (1:7:5) 97 81 N4-Lignoceroyl CA:HC0-60:Glu (1:7:5) 97 82 N4-(5-Methylnonadecanoyl)CA:HCO-60:Glu(1:7:5) 97 CA: Cytosine arabinoside HC0-60 ~ Glu: The same as those defined in Example 1 ~063937 Table 7 Composition I~O. T/C (%) LDso (mg/kg) 81 , 350 400 N4-Nonadecanoylcytosine arabinoside 150 400 N4-Arachidoylcytosine arabinoside 150 400 N4-Heneicosanoylcytosine arabinoside 150 400 N4-Tricosanoylcytosine arabinoside 150 400 N4-Lignoceroylcytosine arabinoside 120 400 N4-(5-Methylnonadecanoyl)cytosine arabinoside 150 400 Example 3 One gram each of the N4-acylcytosine arabinosides indicated in Table 8 and each of the additives shown in Table 9 in the amounts indicated were added to 200 g of ethanol. The mixture was heated at 60C and at 1 atm. for 20 minutes, and then the ethanol was evaporated by heating at 40C and at 0.1 atm.
for 4 hours.
The residue and each of the auxiliary additives shown in Table 10 in the amounts indicated were added to 1 kg of water.
The mixture was heated at 95C and at 1 atm. for 20 minutes with stirring, and cooled in ice water, followed by lyophilizing.

. .
,~
... ' , ' . , ' ' :` ' Thus, the compositions shown in Table 11 ~the numbers correspond to those in Tables 8 to 10) were obtained as white amorphous powders in the yields shown in Table 11.
The anticancer activity (T/C %) and per oral ~oxicity LDso (mg/kg) of these compositions were determined in the same manner as in Example 1 except that an aqueous solution of 400 mg, per kg of body weight of mouse, of each composition calculated as the N4-acylcytosine arabinoside, or 400 mg on the same basis of a 0.5% aqueous solution of methyl cellulose containing each of the N4-acylcytosine arabinosides alone was administered orally to the L-1210 leukemia-inoculated mice three times (on the 3rd, 5th and 7th days). The results are shown in Table 12.

Table 8 No. N4-Acylcytosine arabinoside .
83 N4-Stearoylcytosine arabinoside 84 N4-Stearoylcytosine arabinoside N4-Stearoylcytosine arabinoside 86 N4-Stearoylcytosine arabinoside 87 N4-Myristoylcytosine arabinoside 88 N4-Palmitoylcytosine arabinoside 89 N4-Margaroylcytosine arabinoside N4-(2-Chlorostearoyl)cytosine arabinoside 91 N -(18-Hydroxystearoyl)cytosine arabinoside 92 N -(2-Mercaptostearoyl)cytosine arabinoside 93 N4-Margaroylcytosine arabinoside 94 N4-Margaroylcytosine arabinoside , Table 8 (continued) No. N4-Acylcytosine arabinoside N4-Margaroylcytosine arabinoside : 96 N4-Valeroylcytosine arabinoside 97 N4-Stearoylcytosine arabinoside , Table 9 No. Additive Weight (g) -86 Sodium deoxycholate 5 87 HC0-60/sodium deoxycholate (1:1) 4 88 HC0-60/sodium deoxycholate ~1:1) 4 89 HC0-60/sodium deoxycholate (1:1) 4 HC0-60/sodium deoxycholate (1:1) 4 91 HC0-60/sodium deoxycholate (1:1) 4 92 HC0-60/sodium deoxycholate (1:1) 4 93 Mys-45 5 : .

, . ., .
.
" ,, Table 10 No. Auxiliary additive Weight (g) 83 Glucose 5 84 Glucose and MgC12 (1:2) 15 Glucose and CaCl~ 2) 15 86 Glucose 5 87 Glucose , 5 88 Glucose 5 89 Glucose 5 Glucose S
91 ~lucose 5 92 Glucose 5 93 Glucose 5 94 Glucose 5 MgS04 10 96 Glucose 5 97 NaBr 0.1 Table 11 No. Composition Yield 83 St-CA:HCO-60:Glu (1:5:5) 97 84 St-CA:HCO-60:Glu:MgC12 (1:5:5:10) 97 St-CA:HCO-60:Glu:CaC12 (1:5:5:10) 97 86 St-CA:DeoxNa:Glu (1:5:5) 97 87 My-CA:HCO-60:DeoxNa:Glu (1:2:2:5) 97 88 Pa-CA:HCO-60:DeoxNa:Glu (1:2:2:5) 97 89 Ma-CA:HCO-60:DeoxNa:Glu (1:2:2:5) g7 2-Cl-St-CA:HCO-60:DeoxNa:Glu (1:2:2:5) 97 91 18-Hy-St-CA:HCO-60:DeoxNa:Glu(1:2:2:5) 97 92 2-Me-St-CA:HCO-60:DeoxyNa:Glu(1:2:2:5) 97 93 Ma-CA:Mys-45:Glu(1:5:5) 97 94 Ma-CA:TW-30:Glu (1:5:5) 97 Ma-CA:HCO-60:MgSO4 (1:5:10) 97 96 Va-CA:HCO-60:Glu (1:5:5) 97 97 St-CA:HCO-60:NaBr (1:5:0.1) 97 Compari-son Va-CA

.Y' Table 12 Composition No. T/C (%) LDso (mg/kg) 83 300 above 1600 84 380 above 1600 3B0 above 1600 86 350 above 1600 87 ' 350 1600 88 290 above 1600 89 290 above 1600 290 above 1600 91 290 above 1600 92 290 above 1600 - 95 350 above 1600 96 140 above 1600 97 280 above 1600 Comparisons ST-CA 150 above 1600 My-CA 150 . 1600 Pa-CA 150 above 1600 Ma-CA 150 above 1600 2-Cl-St-CA 150 above 1600 18-Hy-St-CA 150 above 1600 2-Me-St-CA 150 above 1600 Va-CA 110 above 1600 The abbreviations used in Tables 9 to 12 have the following meanings.
St-CA: N4-Stearoylcytosine arabinoside My-CA: N4-Myristoylcytosine arabinoside Pa-CA: N4-Palmitoylcytosine arabinoside Ma-CA: N4-Margaroylcytosine arabinoside 2-Cl-St-CA: N4-(2-Chlorostearoyl)cytosine arabinoside 18-~ly-St-CA: N4-(18-Hydroxystearoyl)cytosine arabinoside 2-Me-St-CA: N4-(2-Mercaptostearoyl)cytosine arabinoside Mys-45: Stearic acid ester of polyoxyethylene with an average degree of polymerization of 45 TW-30: Lanolin havingbonded thereto polyoxyethylene with an average degree of polymerization of 30 Va-CA: N4-Valeroylcytosine arabinoside It can be seen from Table 12 that while the anticancer activity (T/C %) in oral administration of each of the N4-acylcytosine arabinosides alone is 150%, the activities of the compositions containing the N4-acylcytosine arabinosides in-crease to 300 - 380%.

Example 4 Instead of oral administration in Example 3, 400 mg, per kilogram of body weight of mouse, of each of the composi-tions in powder form (calculated as the N4-acylcytosine ara-binoside) or of a mixture of each N4-acylcytosine arabinoside and methyl cellulose (2:1) was solidified in a rocket form, , and administered through the anus three times (once each on the 3rd, 5th and 7th days). The anticancer activities (T/C ~) and LDso values (mg/kg) in intra-anal administration were determined, and the results are shown in Table 13.
From these results, it is seen that the results were much the same for both oral and intra-anal administrations.

Table 13 Compound No. T/C (%) LDso (mg/kg) 83 300 above 1600 84 380 above 1600 380 above 1600 86 350 above 1600 88 280 above 1600 89 280 above 1600 280 above 1600 91 280 above 1600 92 280 above 1600 350 above 1600 96 140 above 1600 97 300 above 1600 - 42,-Table 13 (continued) Compound ~o. TtC (~) LD~n (mg/kg) Comparisons St-CA 150 above 1600 My-CA 150 1600 Pa-CA 150 above 1600 Ma-CA 150 above 1600 2-Cl-St-CA . 150 above 1600 18-Hy-St-CA 150 above 1600 2-Me-St-CA 150 above 1600 Va-CA 110 above 1600 Example 5 One gram of N4-behenoylcytosine arabinoside (AS-22 for brevity) and each of the additives shown in Table 14 in the amounts indicated were added to 400 ml of acetone. The mix-ture was heated at 55C and at 1 atm. for 10 minutes, and then the acetone was evaporated from the solution by heating at 55C
and at 0.2 atm. for 2 hours. The residue was dried in a vacuum desiccator at 20C and at 0.1 atm. for 20 hours. Thus, water-soluble compositions containing AS-22 were obtained in yields of 95 to 99%.
The solubility of each of the water-soluble solids of AS-22 was determined in the following manner. When a clear aqueous solution can be obtained by adding 100 ml of a 0.9% aqueous solution of sodium chloride to a water-soluble solid containing 1 g of AS-22, stirring the mixture in a hot water bath at 90C and rapidly cooling the resulting aqueous solution in an ice water bath , "
- , .., ' ~

the solubility of the water-soluble solid is determined to be more than lg/100 ml. When a precipitate forms under the above conditions, 100 ml. of a 0.9~ aqueous solution of sodium chloride is further added, and the aforesaid heating-rapid cooling procedure is repeated to form a solution. The solubility in this case is calculated as the amount of AS-22 dissolved per lO0 ml of water: The results are also shown in Table 14.

Table 14 No. Additive Weight solubility (g) of AS-22 ~g/100 ~1) 98 Polyoxyethylene (40) hydrogenated 1.8 0.5 castor oil 2 ~1 (HC0-40) 100 ~1 99 Polyoxyethylene (50) hydrogenated 1.8 0.5 castor oil 2 ~1 (HC0-50) 100 ~1 100 Polyoxyethylene (60) hydrogenated 1.8 0.5 castor oil 2 ~1 (HC0-60) 100 ~1 lOl Polyoxyethylene (80) hydrogenated 1.8 0.5 castor oil 2 ~1 (HCO-80) 100 ~1 102 Polyoxyethylene (100) hydrogenated 1.8 0-5 castor oil 2 71 (HCO-lO0) 100 ~1 103 Polyoxyethylene (40) castor oil 1.8 0.5 (C0-40TX) 2 ~1 100 ~1 104 Polyoxyethylene (60) castor oil 1.8 0.5 (CO-60TX) 2 71 ~ s, , . ,.,.~ "~ ~

~063937 I-a_ c ]~ (eontinucd) No Ad(Ijtive Weight Solubilit o,~~~
(~/lOb ml) 105 Polyo~ycthylenc (30) lanolin 1.8 0.5 (TIY-30) 2 71 . 100 ~1 106 Polyo~ycthylenc (40) stearatc 1.5 0.5 t~IYS-40) 2 ~ 1 107 Polyoxycthylene (~5) stearate 1.5 0.5 ~MYS-45) 2 71 lO0 71 108 Polyoxyethylene (5S) stearate 1.5 0.5 (~S-55) 2 ~ 1 100 ~1 - 109 Sodium desoxycholate 2 0.5 >1 ''................................................... 100 ~1 `- 110 AS-22 alone is suspended without the 0 0 use of the additive ' - ' . . .
In the above table, the abbreviations in the p~rentheses are the commodity numbers of the products (under the trademark Nikkol) of Nikko Chemicals Co., Ltd. It is expected that products of similar compositions made by other manufacturers such as Nissan Chemical Co., Ltd. or Atlas Company will have much the same solubilities.

. ' ' .

,' ' ,, ~ '.

.

Examplc 6 To l ~ Or ~S-22 wcrc ad~cd 2 ~ of polyoxycthylcnc (60) hydrogenatcd castor oil (Nikkol IIC0-60, a ploduct for use ;n drugs by Nikko Chcn1icals Co., Itd.), O.l g of polyoxycthylene (40) stcarate (Nikkol ~IYS-40), and 50 ml of cthanol. Thc m~xture was hcated at 75C for 5 minutes; The e~hanol was evaporatcd at 55C
and at 0.2 atm. for 30 minutcs, and thc residue was dried at 20C
and at O.l atm. for 4 hours to afford about 3.l ~ of a water-soluble solid. To the water-soluble solid containing AS-22 thus obtained, lO0 ml of a 0.8% aqueous solution of sodium chloride was added, and the mixture was heated in a hot water bath at 90C
to form a solution which was rapidly cooled in an ice water bath to afford an almost colorless clear 1% aqueous solution of AS-22.
The aqueous solution was passed through a membrane filter (with a pore size of 0.45 ~u) to give a 1% injectable of AS-22.

Example 7 .

To l g of AS-22 were added 2 g of polyoxyethylene (60) ~ .
hydrogenated castor oil (Nikkol ~IC0-60) and 50 ml of tetra-hydrofuran, and the mixture was heated at 50C for lO minutes.
To the resulting solution was added 0.8 g of sodium chloride in pcwder form, and then the tetrahydrofuran was evaporated at 50C
and at 0.2 atm. for 30 minutes. The residue was dried in a desiccator at 20C and at O.l atm. for 20 hours to afford a w;ter-soluble tacky white solid of AS-22.~1C0-60.NaCl. Water (100 ml) was added to the white solid, and the mixture heated in a hot water bath at 90C to form a solution which was rapidly c~oled in an ice water bath to afford a 1% aqueous solution of . ~ .
,. , , ' -.;,. , .
.~ ' AS-22. The aqueous solution was filtered by means of a mil-lipore filter of the type described in Example 6 to afford a 1% aqueous injectable of AS-22 (containing 1% of AS-22, 2% of HC0-60, and 0.8~ of NaCl).

Example 8 Dimethyl acetamide t2 ml) was added to 1 g of AS-22 and 4 g of polyoxyethylene (60) hydrogenated castor oil (Nikkol HC0-60), and the mixture was heated at 90C and at 1 atm. for lO minutes to form a solution. When the solution was allowed to cool to room temperature, it became a white solid. Water (100 ml) was added to the solid, and the mixture was heated at 90C for 2 hours with vigorous stirring to dissolve the solid.
The solution was dipped in ice water, and cooled with vigorous stirring. Thus, a 1% aqueous solution of AS-22 was obtained.

Example 9 Dimethyl acetamide (2 ml) was added to 1 g of AS-22, and the mixture heated at 90C and at 1 atm. for 10 minutes. To the solution was added 100 ml of a 4% aqueous solution of poly-oxyethylene (60) hydrogenated castor oil (Nikkol HC0-60) heated to 90C. The mixture was stirred vigorously at 90C for 2 hours.
A part of AS-22 dissolved. The mixture was rapidly cooled with ice water, and filtered to remove the insoluble part of AS-22 to afford a 0.1% aqueous solution of AS-22.

. . - , .

"' ' '' Example 10 An aqueous solution containing 2~ of dimethyl acetamide and ~ of polyoxyethylene (60) hydrogenated castor oil (Nikkol ~ICO-60) was added to 0.1 g of AS-22, and the mixture heated at 90C. A part of AS-22 dissolved. The mixture was rapidly cooled with ice water, and tlien filtered to remove the insoluble AS^22 to thereby aford a 0.02% aqueous solution of AS-22.

Example 11 Water (100 ml) was added to 0.3 g, 1.5 g or 3.0 g of a water-soluble solid obtained in the same way as in Example 5 from 1 part of AS-22 and 2 parts of polyoxyethylene (60) hydrogenated castor oil. Each of the mixtures obtained was heated at 90C for 2 hours. The solution was allowed to cool to room temperature.
On the other hand, 100 ml of water was added to 0.3 g, 1.5 g or 3.0 g of a water-soluble solid prepared from 1 part of AS-22 and 2 parts of polyoxyethylene (60) hydrogenated castor oil, and each of the mixtures was heated at 90C for 2 hours. The solution was rapidly cooled in ice water.
It was found that by rapid cooling, the aqueous solutions ; containing 0.1 g, 0.5 g and 1.0 g of AS-22 were all clear, but by spontaneous cooling, the aqueous solutions containing 0.1 g and 0.5 g of AS-22 were clear but the aqueous solution containing 1.0 g of AS-22 was non-transparent showing that AS-22 did not completely dissolve. Samples rapidly cooled were still trans-parent after storage for a week at room temperature, whereas samples spontaneously cooled developed white precipitates on storage for only one day at room temperature.
:

~063937 Example 12 Ethanol (40 ml) was added to 1 g of AS-22 and 2 g of polyoxyethylene (60) hydrogenated castor oil (Nikkol HCO-60), and the mixture heated at 60C. The ethanol was evaporated from the solution at 60C under reduced pressure. The residue was dried in a vacuum desiccator to afford 3 g of a white water-soluble solid. To the solid was added 100 ml of a 0.8% aqueous solution of sodium chloride, and the mixture heated in a hot water bath at 90C for 2 hours. The solution was rapidly cooled in an ice bath, and filtered by a millipore filter having a pore size of 0.45 ~u to remove microorganisms present. Thus, an in-jectable of AS-22 containing 1% of AS-22, 2% of HCO-60 and 0.8%
of NaCl was obtained.

Example 13 Each of the organic solvents indicated in Table 15 was added in the amounts indicated to 1 g of AS-22 and 2 g of poly-oxyethylene (60) hydrogenated castor oil (Nikkol HCO-60).
Each of the mixtures was heated at each of the temperatures indicated in Table 15 at 1 atm for 10 minutes. The solvent was-evaporated from the resulting solution at each of the temperatures shown in Table 15 at 0.2 atm. The residue was dried at 25C
for 20 hours in a vacuum desiccator. The amount of water required to dissolve the resulting water-soluble solids was determined.
It was found that all of these solids dissolved in 50 ml of water, and no difference was observed.
As a control, the same procedure as above was performed using 100 ml of hexane incapable of dissolving AS-22. It was .

, . ', ' ' ~'':

. .

found that ad~ition of hexane to a mixture of AS-22 and poly-oxyethylene (60) hydrogenated castor oil resulted in the dis-solving of only the polyoxyethylene hydrogenated castor oil in water, and AS-22 remained almost undissolved in water.

Table 15 Dissolving Evaporating Solubility Solvent Amount temper- temperature of AS-22 (ml) ature(C) (C) (g/100 ml) Methanol 200 75 50 2 Ethanol 50 75 50 2 n-Propanol 50 60 60 2 iso-Propanol 50 60 60 2 Tetrahydrofuran 20 50 50 2 Tetrahydropyran 20 50 50 2 Dioxane 50 80 80 2 Acetone 200 50 50 2 Methyl ethyl ketone 200 50 50 2 Dimethyl acetamide 20 80 80 2 Dimethyl formamide 20 80 80 2 Dimethyl sulfoxide 20 80 80 2 Diethyl acetamide20 80 -. 80 2 Ethyl acetate 500 50 40 2 Butyl acetate 500 50 40 2 Diethyl ether 500 35 - 40 2 Methylethyl ether500 35 40 2 Pyridine 50 40 40 2 Triethanolamine 50 40 40 2 Acetic acid 50 40 50 2 n-Hexane 1000 50 50 less than 0.02 ~xample 14 Acetone (50 ml) was added to l g of AS-22 and 4 g of polyoxyethylene (60) hydrogenated castor oil (Nikkol HCO-60) and the mixture heated at 55C and at 1 atm. for 2 hours. They did not completely dissolve. The acetone was evaporated from the mixture at 55C and at 0.2 atm. for 2 hours, and then water was added in an amount of 100 ml. The mixture was heated at 90C, and the resulting solution was rapidly cooled in an ice bath to obtain an aqueous solution containing 1% of AS-22 and 4% of HCO-60.

Example 15 One gram of each of the N4-acylcytosine arabinosides shown in Table 16 and 10 g of polyoxyethylene (60) hydrogenated castor oil (Nikkol HCO-60) were dissolved in 200 ml of acetone by heating at 55C and at 1 atm. for 10 minutes. The acetone was evaporated at 55C and at 0.2 atm. for 2 hours. The residue was dried in a vacuum desiccator at 20C and at 0.1 atm. for 20 hours to obtain an aqueous solid containing each of the N4-acylcytosine arabinosides in a yield of 99%. Water (100 ml) was added to 1 g of each of the water-soluble solids consisting of each of the N4-acylcytosine arabinosides and polyoxyethylene (60) hardened castor oil in a ratio of 1:10, and the mixture stirred in a hot water bath at 90C. The aqueous solution obtained was rapidly cooled in an ice water bath. Thus, clear solutions were obtained in a yield of 99%.

~o63937 Table 16 Compound Acyl group in the AS:I-ICO-60 Proportions No. N4-acylcytosine ratio in of As and arabinoside the water- HCO-60 in soluble aqueous solid solution 111 Valeryl 1 : 10 0.1~ 1%
112 Lauroyl 1 : 10 0.1 113 Palmitoyl 1 : 10 0.1 114 Stearoyl 1 : 10 0.1 115 Arachidoyl 1 : 10 0.1 116 Heneicosanoyl 1 : 10 0.1 117 Erucoyl 1 : 10 0.1 118 Behenoyl 1 : 10 0.1 119 Lignoceroyl 1 : 10 0.1 120 Hexatriacontanoyl 1 : 10 0.1 121 2-Chlorostearoyl 1 : 10 0.1 122 18-Hydroxystearoyl 1 : 10 0.1 123 2-Mercaptostearoyl 1 : 10 0.1 124 5-~ethylnonadecanoyl 1 : 10 0.1 - 1 125 Benzoyl 1 : 10 0.1 126 Phenylbutyryl 1 : 10 0.1 127 p-Nitrobenzoyl 1 : 10 0.1 * AS: N4-acylcytosine arabinoside ~o63937 Example 16 The solubility (I) in water of a composition consiting of an N4-acylcytosine arabinoside, an additive and an auxiliary additive (to be referred to as a three-component composition) J
the solubility (II) in an aqueous solution of an auxiliary additive of a composition consisting of an N4-acylcytosine arabinoside and an additive (to be referred to as a two-component .
composition), and the solubility (III) in water of the two-component composition were determined under the following three conditons.
(A) When stirring is performed at room temperature for 10 minutes;
(B) When stirring is performed at 90C for 10 minutes, and then the stirred mixture is allowed to cool to room temperature; and ~C) When stirring is performed at 90C for 10 minutes, and then the stirred mixture is rapidly cooled in ice water, and thereafter its temperature is retu~ned to room temperature.
Specific procedures were as follows: One gram, calculated as the N4-behenoylcytosine arabinoside (AS-22 for brevity), of each of the three-component composition Nos. 1 to 76 obtained in Example 1 was added to 100 ml of water, and the mixture was stirred at room temperature for 10 minutes and then filtered by a millipore filter (pore size 0.45~u). The aqueous solution was distilled at 50C and at 0.02 atm. for 4 hours. The residue was vacuum dried at 0.001 atm. and at 20C for 24 hours.

... .

By measuring the weight of the dried residue, the solubility of the composition under this condition (IA) was obtained.
Similarly, the solubilities of the composition under conditions B and C (IB and IC) were measured. The solubilities are expressed by the weight in grams of AS^22 dissolved in 100 ml of water. When AS-22 (1 g) completely dissolved, the above composition was fur~her added to the resulting solution to see whether AS-22 dissolved beyond 1 g under the same conditions.
Next, one gram, calculated as AS-22, of each of the two-component composition Nos. 1' to 76' obtained in Example 1 by dioxane treatment (each consisting of 1 g of AS-22 and each of the additives shown in Table 1 in the amounts shown in Table l;
the compositions 1' to 76' correspond to Nos. 1 to 76) was added to an aqueous solution consisting of lOO ml of water and each of the auxiliary additives shown in Table 2 in the amounts in-dicated in Table 2. In the same manner as described above, its solubilities under the conditions A, B and C (IIA, IIB and IIC) were measured.
Finally, 1 g, calculated as AS-22, of each of the two-component composition Nos. 1' to 76' was added to 100 ml of water, and in the same manner as above, its solubilities under the conditions A, B and C (IIIA, IIIB and IIIC) were measured.
The results are shown in Table 17.

Table 17 Composi- I C~posi- II III
tion ~ tion No. A B ~ No. A B C A B C
: l0.1 0.1 0.1 1' 0.050.1 0.1 0.01 0.050.1 21 >1 >1 2' 0.3 ~1 ~1 0.01 0.3 ~1 30.1 0.1 0.1 3' 0.050.1 0.1 0.01 0.050.1 41 >1 ~1 4' 0.4 >1 >1 0.01 0.4 ?1 S1 >1 ~1 5' 0.4 ~1 ~1 0.01 0.4 ~1 60.1 0.1 0.1 6' 0.050.1 0.1 0.01 0.050.1 71 >1 ?1 7' 0.3 >1 >1 0.01 0.3 ?1 81 0.1 0.1 8' 0.050.1 0.1 0.01 0.050.1 91 >1 ~1 9' 0.3 >1 ~1 0.01 0.3 ~1 : 100.1 0.1 0.1 10' 0.050.1 0.1 0.01 0.050.1 111 >1 ~1 11' 0.3 >1 >1 0.01 0.3 71 120.1 0.1 0.1 12' 0.050.1 0.1 0.01 0.050.1 131 >1 ~1 13' 0.3 ~1 ~1 0.01 0.3 ~1 140.2 0.2 0.2 14' 0.1 0.2 0.2 0.01 0.1 0.2 151 >1 ~1 15' 0.5 >1 ~1 0.01 0.5 ~1 161 ~1 ~1 16' 0.5 >1 ~1 0.01 0.5 ~ 1 171 ~1 ~1 17' 0.5 ~ 1 ~1 0.01 0.5 ~1 180.1 0.1 0.1 18' 0.050.1 0.1 0.01 0.050.1 19 -1 >1 >1 19' 0.3 ~1 ?1 0.01 0.3 ~1 200.1 0.1 0.1 20' 0.050.1 0.1 0.01 0.050.1 211 >1 71 21' 0.3 ~1 ~1 0.01 0.3 ~1 220.1 0.1 0.1 22' 0.050.1 0.1 0.01 0.050.1 231 ~1 ~1 23' 0.3 ?1 ~1 0.01 0.3 ~ 1 240.1 0.1 0.1 24' 0.050.1 0.1 0.01 0.050.1 i,' ' ' .. . .

Tablc 17 (continu~d) Compos i - I Compos i - I I I I I
tion tion No. A B C No. A B C A B C
1 71 ~1 25 '0.3 ~ 1 710.01 0.3 71 26 0.1 0.1 0.1 26'0.05 0.1 0.1 0.01 0.05 0.1 27 1 ~1 ~1 27' 0.3 ~1 ~10.01 0.3 7 1 28 0.1 0.1 0.1 28'0.05 0.1 0.1 0.01 0.05 0.1 29 1 ~1 ~1. 29' 0.3 71 ~10.01~0.3 ~1 0.1 0.1 0.1 30'0.05 0.1 0.1 0.01 0.05 0.1 31 1 ~1 >1 31' 0.3 ~1 ~10.01 0.3 71 32 0.1 0.1 0.1 32'0.05 0.1 0.1 0.01 0.05 0.1 33 1 ~1 >1 33' 0.3 71 ~10.01 0.3 ~1 34 0.1 0.1 0.1 34'0.05 0.1 0.1 0.01 0.05 0.1 1 ~1 ~1 35' 0.3 ~1 ~10.01 0.3 ~1 36 0.1 0.1 0.1 36'0.05 0.1 0.1 0.01 O.OS 0.1 37 1 ~1 ~1 37 '0.3 ~1 ~10.01 0.3 ~ 1 38 0.1 0.1 0.1 38'0.05 0.1 0.1 0.01 0.05 0.1 39 1 ~1 ~1 39' 0.3 ~1 ~10.01 0.3 ~1 0.1 0.1 0.1 40'0.05 0.1 0.1 0.01 0.05 0.1 41 1 >1 ~1 41' 0.3 ~1 ~10.01 0.3 ~1 42 0.1 0.1 0.1 42'0.05 0.1 0.1 0.01 0.05 0.1 43 1 ~1 ~1 43' 0.3 71 ~10.01 0.3 ~1 44 0.1 0.1 0.1 44'0.05 0.1 0.1 0.01 0.05 0.1 1 >1 >1 45' 0.3 ~1 ~10.01 0.3 ~1 46 0.1 0.1 0.1 46'0.05 0.1 0.1 0.01 0.05 0.1 47 1 ~1 ~1 47' 0.3 ~1 >10.01 0.3 71 48 1 71 ~1 48' 0.4 ~1 ~10.01 0.4 ~1 49 1 ~1 ~1 49 ' 0.4 ,71 71 0.01 0.4>1 1 >1 >1 50' 0.4 ~1 ~1 0.01 0.471 ' ' ., : . .

~o63937 Table 17 (continued) Composi- I Composi- II III
tlon A B C No. A B C A B C
51 1 ~l ~1 51' 0.4 >1 ~1 0.010.4 ~1 - 52 1 >1 >1 52' 0.4 >1 >1 0.010-.4 ~1 53 1 ~1 >1 53' 0.4 ~1 ~1 0.01~-4 >1 54 1 ?1 71 54t 0.4 ~1 71 0.010.4 ~1 1 ~1 ~1 55' 0.5 ~ 1 >1 0.010l5 ~1 56 1 >1 ~1 56' 0.5 ~ 1 >1 0.019.5 ~1 57 1 >1 ~1 57' 0.5 ~1 ~1 0.010.5 ~1 58 1 71 ~1 58' 0.5 71 ~1 0.010.5 71 59 1 ~1 ~l 59' 0.5 71 ~1 0.010.5 >1 1 71 ~1 60' 0.5 ~1 71 0.010.5 ~1 61 1 ~1 >1 61' 0.5 ~1 ~1 0.010.5 ~1 62 1 71 71 62' 0.5 ~1 71 0.010.5 ~1 63 1 ~1 >1 63' 0.5 ~1 71 0.010.5 ~1 - 64 1 ~1 >1 64' 0.5 ~1 ~l 0.010.5 71 1 ~1 ~1 65' 0.5 71 ~1 0.010.5 ~1 66 1 ~1 ~1 66' 0.5 71 71 0.010.5 ~1 67 1 ~1 ~1 67' 0.5 ~1 71 0.010.5 ~1 68 1 ~1 ~1 68' 0.5 71 >1 0.010.5 ~ 1 69 1 71 ~1 69' 0.5 ~ 1 ~71 0.010.5 71 1 ~1 ~1 70' 0.5 71 ~1 0.010.5 71 71 1 ~1 ~1 71' 0.5 ~1 ~1 0.010.5 7 1 72 1 71 ~1 72' 0.5 71 71 0.010.5 ~71 73 1 ~1 71 73' 0.5 ~1 ~1 0.010.5 71 74 1 71 ~1 74' 0.5 71 ~ 1 0.010.5 71 1 71 ~1 75' 0.5 71 ~1 0.010.5 ~1 76 1 ~1 ~1 76' 0.5 71 ;7 1 0.010.5 7 1 ~,.

, ' ~ , ~063937 It can be seen from Table 17 that under condition C
in which after stirring for 10 minutes at 90C, the stirred mixturc has rapidly cooled in ice water and then its temperature was returned to room temperature, compositions containing the auxiliary additives and those not containing them had the same solubilities, but that under condition B in which after stirring for 10 minutes at 90C, the stirred mixture was allowed to cool spontaneously to roo'm temperature, compositions containing the auxiliary additives had higher solubility than those not contain-ing the auxiliary additives.
On the other hand, under condition A in which stirring was effected for 10 minutes at room temperature, the three-component compositions which contained the auxiliary additives from the start had higher solubility than the two-component compositions to which the auxiliary additives were added later in the form of aqueous solution.
While the invention has been described in detail and with referencè to the specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirir and scope thereof.
:'

Claims (34)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1, A composition comprising (1) an N4-acylcytosine arabino-side and (2) at least one additive selected from the group consisting of (a) polyoxyethylene-bonded hydroxy fatty acid glycerin esters, (b) polyoxyethylene fatty acid esters, (c) poly-oxyethylene-bonded lanolin and (d) bile acids, wherein the amount of (2) is 0.1 to 20 parts by weight per part by weight of (1).

2. A composition comprising (1) an N4-acylcytosine arabino-side, (2) at least one additive selected from the group consisting of (a) polyoxyethylene-bonded hydroxy fatty acid glycerin esters, (b) polyoxyethylene fatty acid esters, (c) polyoxyethylene-bonded lanolin and (d) bile acids, and (3) at least one auxiliary additive selected from the group consisting of saccharides aliphatic polyols, pharmaceutically acceptable inorganic chlorides, bromides and sulfates, and aromatic carboxylic acids or pharmaceuti-cally acceptable salts thereof, wherein the amounts of (2) and (3) are both 0.1 to 20 parts by weight per part by weight of (1).

3. The composition of Claim 1 or 2, wherein the acyl group in the N4-acylcytosine arabinoside has 14 to 24 carbon atoms.

4. The composition of Claim 2, wherein the auxiliary additive is at least one compound selected from the group consisting of glucose, NaCl, CaCl2, MgCl2, MgSO4 and sodium salicylate.

5. The composition Claim 1, wherein the additive is at least one compound selected from the group consisting of bile acids and glycerin esters of hydroxy fatty acids containing 10 to 20 carbon atoms having bonded thereto polyoxyethylene with an average degree of polymerization of 10 to 200 moles.

6. The composition of Calim 1, wherein the bile acid is sodium deoxycholate or sodium dehydrocholate.

7. A process for preparing a composition of Claim 1, which comprise dissolving the N4-acylcytosine arabinoside and the additive in a solvent, and then evaporating the solvent.

8. A process for preparing a composition of Claim 1, which comprise dissolving the N4-acylcytosine arabinoside and the additive in a solvent, evaporating the solvent and then adding the auxiliary additive and water to the residue.

9. A process for preparing a composition of Claim 2, which comprise dissolving the N4-acylcytosine arabinoside and the additive in a solvent, evaporating the solvent and then adding the auxiliary additive and water to the residue followed by evaporating the water.

10. A process of Claim 7, 8, or 9 wherein the solvent capable of dissolving the N4-acylcytosine arabinoside and the additive is selected from the group consisting of ketones, ester, aliphatic ethers, cyclic ethers, amides, sulfoxides, alcohols, bases, and acids.

11. The process of Claim 7, 8 and 9 wherein the acyl group in the N4-acylcytosine arabinoside contains 14 to 24 carbon atoms.

12. The process of Claim 8 or 9 wherein the auxiliary additive is at least one saccharide selected form monosaccharides and disaccharides.

13. The process of Claim 8 or 9 wherein the auxiliary additive is at least one pharmaceutically acceptable inorganic halide selected from the group consisting of alkali metal chlorides, alkaline earth metal chlorides, alkali metal bromides and alkaline earth metal bromides.

14. The process of Claim 8 or 9 wherein the auxiliary additive is at least one aromatic carboxylic acid or its pharmaceutically acceptable salt selected from the group consisting of benzoic acid, alkali metal benzoates, ammonium benzoate, alkaline earth metal benzoates, salicylic acid alkali metal salicylates and alkaline earth metal salicylates.

15. The process of Claim 8 or 9 wherein the auxiliary additive is at least one compound selected from the group consisting of glucose, NaCl, CaCl2, MgSO4 and sodium salicylate.

16. The process of Claim 7, wherein the additive is at least one compound selected from the group consisting of bile acids and glycerin esters of hydroxy fatty acids containing 10 to 20 carbon atoms having bonded thereto polyoxyethylene with an average degree of polymerization of 10 to 200 moles.

17. The process of Claim 7, wherein the polyoxyethylene-bonded hydroxy fatty acid glycerin ester is hydrogenated castor oil having bonded thereto polyoxyethylene with an average degree of polymerization of 40 to 100 moles or glycerin hydroxystearate having bonded thereto polyoxyethylene with an average degree of polymerization of 40 to 100 moles.

18. The process of Claim 7, wherein the bile acid is sodium deoxycholate or sodium dehydrocholate.

19. A process for water-solubilizing an N4-acylcytosine arabinoside, which comprises adding at least one additive selected from the group consisting of (a) polyoxyethylene-bonded hydroxy fatty acid glycerin ester, (b) polyoxyethylene fatty acid esters, (c) polyoxyethylene-bonded lanolin and (d) bile acids to the N4-acylcytosine arabinoside.

20. A process for water-solubilizing an N4-acylcytosine arabinoside, which comprises adding at least on additive selected from the group consisting of (a) polyoxyethylene-bonded hydroxy fatty acid glycerin ester, (b) polyoxyethylene fatty acid ester, (c) polyoxyethylene-bonded lanolin and (d) bile acids, and further adding at least one auxiliary additive selected from the group consisting of saccharides, aliphatic polyols, pharmaceutically acceptable inorganic chloride, bromides and sulfates, and aromatic carboxylic acids or pharmaceutically acceptable salts thereof the the N4-acylcytosine arabinoside.

21. The process of Claim 19 wherein the N4-acylcytosine arabinoside and the additive are dissolved in a solvent therefor, then the solvent is evaporated, and water, or both water and the auxiliary additive, or an aqueous solution of the auxiliary additive is added to the residue and the mixture is heated.

22. The process of Claim 19 wherein the N4-acylcytosine arabinoside and the additive are dissolved in a solvent therefor, then the solvent is evaporated, and water, or both water and the auxiliary additive, or an aqueous solution of the auxiliary additive is added to the residue and the mixture is heated, followed by evaporating water from the solution.

23. The process of Claim 19 wherein the additive is used in an amount of 0.1 to 20 parts by weight per part by weight of the N4-acylcytosine arabinoside.

24. The process of Claim 20 wherein both the additive and the auxiliary additive are used in amounts of 0.1 to 20 parts by weight per part by weight of the N4-acylcytosine arabinoside.

25. The process of Clam 21 or 22 wherein the solvent capable of dissolving the N4-acylcytosine arabinoside and the additive is selected from the group consisting of ketones, esters, aliphatic ethers, cyclic ethers, amides, sulfoxides, alcohols, bases and acids.

26. The process of Claim 19 or 20 wherein the acyl group of the N4-acylcytosine arabinoside has 14 to 24 carbon atoms.

27. The process of Claim 19 or 20 wherein the additive is at least one compound selected form the group consisting of bile acids and glycerin esters of hydroxy fatty acids containing 10 to 20 carbon atoms having bonded thereto polyoxyethylene with an average degree of polymerization of 10 to 200 moles.

28. The process of Claim 20 wherein the auxiliary additive is at least one compound selected from the group consisting of glucose, NaCl, CaCl2, MgCl2, MgSO4 and sodium salicylate.

29. The process of Claim 19 wherein the N4-acylcytosine arabinoside and additive are dissolved in a solvent at a pressure of 1 to 2 atms. and at a temperature of -20°C to the boiling point of the solvent, for 1 minute to 20 hours, and then, the solvent is evaporated at a pressure of 0.001 to 1 atm.
and at a temperature of 0°C to the boiling point of the solvent, for 5 minutes to 20 hours, and, the mixture is then dried at a pressure of 0.001 to 0.5 atm. and at a temperature of 10 to 30°C for 4 to 100 hours.

30. The process of Claim 19 or 20 wherein the N4-acylcytosine arabinoside and additive are dissolved in a solvent at a pressure of 1 to 2 atms. and at a temperature of -20°C to the boiling point of the solvent, for 1 minute to 20 hours, and then, the solvent is evaporated at a pressure of 0.001 to 1 atm.
and at a temperature of 0°C to the boiling point of the solvent, for 5 minutes to 20 hours, and, the mixture is then dried at a pressure of 0.001 to 0.5 atm. and at a temperature of 10 to 30°C for 4 to 100 hours and water, or both the auxiliary additive and water, or an aqueous solution of the auxiliary additive, is added to the water-soluble solid mentioned above consisting of the N4-acylcytosine arabinoside and the additive, and the mixture is heated at 1 to 1.5 atms. and at 60 to 120°C for 1 minute to 4 hours to from a solution, and when the auxiliary additive is not added, the solution obtained be allowed to cool spontaneously, or rapidly cooled to -40°C to +20°C with flowing water, ice water,dry ice-acetone, or the like.

31. The process of Claim 19 or 20 wherein the N4-acylcytosine arabinoside and additive are dissolved in a solvent at a pressure of 1 to 2 atms. and at a temperature of -20°C to the boiling point of the solvent, for 1 minute to 20 hours, and then, the solvent is evaporated at a pressure of 0.001 to 1 atm. and at a temperature of 0°C to the boiling point of the solvent, for 5 minutes to 20 hours, and, the mixture is then dried at a pressure of 0.001 to 0.5 atm. and at a temperature of 10 to 30°C for 4 to 100 hours and water, or both the auxiliary additive and water, or an aqueous solution of the auxiliary additive, is added to the water-soluble solid mentioned above consisting of the N4-acylcytosine arabinoside and the additive, and the mixture is heated at 1 to 1.5 atms. and at 60 to 120°C for 1 minute to 4 hours to form a solution, and when the auxiliary additive is not added, the solution obtained be allowed to cool spontaneously, or rapidly cooled to -40°C + 20°C with flowing water, ice water, dry ice-acetone, or the like, followed by evaporating the water from the solution.

32. The process of claim 20 wherein the N4-acylcytosine arabinoside and the additive are dissolved in a solvent therefor, then the solvent is evaporated, and water, or both water and the auxiliary additive, or an aqueous solution of the auxiliary additive is added to the residue and the mixture is heated.

33. The process of claim 20 wherein the N4-acylcytosine arabinoside and the additive are dissolved in a solvent therefor, then the solvent is evaporated, and water or both water and the auxiliary additive, or an aqueous solution of the auxiliary additive is added to the residue and the mixture is heated, followed by evaporating water from the solution.

34. The process of claim 32 or 33 wherein the solvent capable of dissolving the N4-acylcytosine arabinoside and the additive is selected from the group consisting of ketones, esters, aliphatic ethers, cyclic ethers, amides, sulfoxides, alcohols, bases and acids.