SK237290A3 - Highly water soluble, stable crystalline salt of 2',3'- -dideoxy-2',3'-didehydrothymidine, method of producing the same and pharmaceutical composition containing same - Google Patents

Description

HIGH SOLUBLE, STABLE CRYSTALLINE 2 ', 3'DIDEOXY ^' IN WATER S'-DIDEHYDROTYMIDINE, S? O ^ <Pg her A FAitM Aéei (T / éXV '? & 2ΓΓΛ / & Ζ) 0 £ more

Technical field

The invention relates to a highly water soluble and stable salt of 2 ', 3'-dideoxy 2', 3'-didehydrotymidine with antiviral activity, including against retroviruses. In particular, sodium salt may be mentioned.

BACKGROUND OF THE INVENTION

Infectious viral diseases are a serious health problem. Progress in the treatment of infectious viral diseases requires, in particular, the development of selective antiviral agents which, of course, are not intended to be detrimental to hunting normal cell lines. At present, experiments are carried out with a number of antiviral agents which appear to have some selectivity. It is a nucleoside analogue, generally a structural analogue of natural nucleosides. Structural modifications, as in part of the purine or pyrimidine base and / or carbohydrate component, may result in synthetically modified derivatives which, upon incorporation into the viral nucleic acid, interrupt the further steps of the synthesis of such viral nucleic acid during its formation.

The efficacy of these antiviral agents depends on the selective conversion of virus enzymes, but not the host enzyme, from the corresponding nucleotide analogue, which is then converted to triphosphates with subsequent incorporation into the viral nucleic acid. A major problem in this case is the emergence of certain viral strains, whose enzymes cause only minor phosphorylation of nucleic acids and analogues. To circumvent this problem, it may be possible to use intact nucleotide analogs as antiviral agents for incorporation into the nucleic acids of the virus.

European Patent Application 273 277 (Lin and Prusoff) discloses the use of 2 ', 3'-dideoxy-2', 3'-didehydrotymidine for the treatment of patients with retroviral infection.

Erik de Clercq describes, see Potential Drugs for the Treatment of AIDS, Journal of Antimicrobial Chemotherapy, 23, Supplement A, p. 35-46 (1989) use of dideoxynucleoside analogues to inhibit the infectivity and cytopathic effect of human immunodeficiency virus HIV.

SUMMARY OF THE INVENTION

The present invention relates to water-soluble, stable crystalline salts of 2 ', 3'-dideoxy-2', 3'-didehydrotymidine of formula I, see also D4T

.H ₂ O

d) wherein X is a cation such as sodium, potassium or magnesium.

The present invention also includes pharmaceutical compositions which contain as an active ingredient an antiviral effective amount of these salts together with a solid, liquid or even gaseous carrier or a physiologically acceptable diluent.

Such compositions can be used to treat warm-blooded individuals, for example humans.

As mentioned hereinbefore, the invention relates in particular to cationic salts of the substance, which are suitable from a pharmaceutical point of view, for example sodium, lithium, potassium, calcium and magnesium salts, the salts may also contain organic cations, alkaline earth metals, ammonium or quaternary ammonium ions. A preferred salt is the sodium salt.

The metal salts can be prepared by treating the metal with 2 ', 3'-dideoxy-2', 3'-didehydrotymidine. The less soluble salt precipitates out of solution, the more soluble salt remains in solution.

The compound of the invention has the desired antiviral effect, such as Herpes simplex I, Herpes simplex II, cytomegalovirus, herpes virus, influenza, vaccinia, polio, rubella, varicella, cowpox, Epstein-Barr virus, measles virus , an effect against human respiratory disease viruses, papillomavirus and Sinbis virus has also been observed; only part of the viruses against which the sodium salt is effective has been listed. In addition, it is effective against retroviruses, for example against human immunodeficiency virus, i. HIV.

As mentioned above, this sodium salt is a useful and effective ingredient of pharmaceutical formulations in human and veterinary medicine for the treatment and prophylaxis of diseases caused by retroviruses. Examples of medical indications are:

1. Treatment or prophylaxis of retrovirus infection in humans.

2. The treatment or prophylaxis of diseases caused by HIV, first termed HTLV / LAV or AIDS, further stages associated with infection by the virus, such as ARC, i. AIDS-associated complex and also Las, i. lymphatic adenopathy syndrome, as well as immunological system deficiency and encephalopathy caused by these retroviruses.

3. Treatment or prophylaxis of HTLVI or HTLVII infections.

4. Treatment or prophylaxis of AIDS carriers where the disease is already communicable.

5. Treatment and prophylaxis of diseases caused by hepatitis B virus

Examples of indications for use of these salts in veterinary medicine are the following:

1. Maedivisna in sheep and goats.

2. Progressive pneumonia virus in sheep and goats.

3. Inflammatory joint virus and encephalitis in sheep and goats.

4. Zwoegerziekte virus in sheep.

5. Infectious anemia virus in horses.

6. Leukemia virus infection in cats.

When used against viral diseases, the compound of the invention may be formulated as a pharmaceutical composition. These may contain, in addition to the active ingredient, pharmaceutically acceptable carriers. Typical carriers and methods of making the compositions are described in Remington's Pharmaceutical Sciences, 17th edition, A.R. Cennaro, edited by the Mack Publishing Company, 1985.

The active ingredient of the present invention can be administered systemically to warm-blooded individuals, including humans. It can be administered orally, rectally or parenterally, in this case intramuscular, intravenous, subcutaneous, or the substance can be administered via the nasal mucosa. Usually, when administered orally, it is necessary to increase the amount of compound to achieve the same effect as parenteral administration. In accordance with clinical practice, it is desirable to administer the active ingredient in an amount that will produce the desired antiviral effect without causing undesirable side effects.

In both treatment and prophylaxis, the compound of the invention is usually administered in the form of a pharmaceutical composition comprising the active ingredient and a carrier or excipients. The pharmaceutical compositions comprise a compound of the invention in an amount of 100 to 0.5% in combination with a pharmaceutical carrier, and may be one or more solid, semi-solid or liquid, i.e., diluents, fillers, and excipients. All must be nontoxic, inert, i.e. pharmaceutically acceptable.

Preferably, the pharmaceutical composition is in unit dosage form, i.e., physically discrete units, each containing a predetermined amount of active ingredient that corresponds to a fraction or multiple of the calculated dose required to produce the desired effect. The composition may also contain other active ingredients.

Preferably, the pharmaceutical compositions and preparations contain 50 mg to 2 g of active ingredient per unit dose, and can be tablets, including those intended to be dissolved under the tongue, capsules, powders, granules, suspensions in water or oil, syrups, elixirs and aqueous solutions. Preferred dosage forms for oral administration are tablets and capsules, which may contain other excipients such as binding agents such as syrups, acacia gum, gelatin, sorbitol, tragacanth or polyvinylpyrrolidone, and fillers such as lactose, sugar, corn starch, calcium phosphate, sorbitol or glycine, glidants such as magnesium stearate, talc, polyethylene glycol or silica, disintegrants such as starch, inorganic or organic buffers, and wetting agents such as sodium lauryl sulfuric acid.

Solutions or suspensions of such compounds in a conventional vehicle may be used for parenteral administration. For intravenous injections, these are aqueous solutions, for intramuscular injections, suspensions in oil. Compositions of the desired clarity and stability for parenteral use can be obtained by dissolving 0.1-35% by weight of the active ingredient in water or a vehicle containing a polyhydric aliphatic alcohol such as glycerol, propylene glycol and polyethylene glycol, or a mixture thereof. substances. Polyethylene glycols are mixtures of non-volatile, usually liquid, water-soluble and organic-liquid polyethylene glycols having a molecular weight of 200 to 1,500.

The compounds are hydrolyzed under acidic conditions. For optimal bioavailability, tablets, capsules and granules for oral administration should be enteric coated or contain a strong buffer against gastric juice, both of which may also be used.

The salt of the present invention is stable, crystalline with high solubility in water, above 300 mg / ml, making it ideally suited for the preparation of injectable solutions for parenteral administration using a small volume. The high alkalinity at pH 9.5-11 of this salt ensures their own buffering ability under the action of stomach acid. Thus, it is possible to use a smaller amount of buffer when processed into oral forms.

The salt of the present invention and similar salts are reversibly immobilized in enol form and can thus be considered as intermediates for the synthesis of various potential biological derivatives such as enol esters and enol ethers. These ester and ether groups may also have the role of protecting groups to allow synthetic work on other moieties or functional groups of the molecule.

From the point of view of biological activity, these substances have an antiviral effect, particularly suitable for their use in the treatment of viral infections. These are mainly mammalian viral infections, including retroviral infections.

An effective dose is in the range of 0.1 to 5 mg, preferably 1 to 4 mg / kg of weight. For clinical purposes, the compounds of the invention may be administered in a similar manner to the comparator azidovudine (AZT). In clinical use, the dosage should be carefully adjusted for each individual case and the dosage will vary according to usual factors such as age, weight, general condition of the patient, route of administration and the nature and severity of the disease being treated. Usually, for oral administration, the dosage will be in the range of 150 mg to 5 g, preferably 50 to 1500 mg of the compound in question, one to three times daily. In some cases, it may be possible to achieve a sufficient therapeutic effect even at lower doses, but sometimes higher doses than indicated may be necessary.

The substance underlying the present invention will be described in more detail by way of example, but only to illustrate the invention, and in no way limit it.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail with reference to the accompanying drawings:

In the drawing no. 1 is an IR spectrum of the sodium salt of 2 ', 3'-dideoxy-2', 3'-dihydrothymidine.

In the drawing no. 2 is a TGA thermal analysis run for the same sodium salt.

In the drawing no. 3 is a DSC thermal analysis run for the same sodium salt.

In the drawing no. 4 are X-ray diffraction data for the same sodium salt.

In the drawing no. 5 is the NMR spectrum of the same sodium salt.

DETAILED DESCRIPTION OF THE INVENTION

Process for preparing D4T sodium salt hydrate

mol. weight D4T = 224.2 mol. NaOH mass = 40 g D4T / 224.21 = X / 40 = 170.4 mg NaOH / 40

This means that 4.46 ml of 1 N sodium hydroxide solution is equivalent to 1 g

D4T so that the molar ratio of both substances is 1: 1.

1. Add 1 g of D4T to 4.7 ml of 1 N aqueous sodium hydroxide solution (1.5 mol equivalents) and stir the reaction mixture gently at 15-25 ° C for 5 minutes. A solution having a pH of 9.5 to 11 is obtained.

2. If necessary, the solution may be clarified by passing through a 0.2 to 0.45 micron orifice filter, such as Celman HT-Tuffryn. These two steps usually last 90 minutes.

3. The sodium salt solution is added to 50 to 75 ml of vigorously stirred isopropyl alcohol or acetone over 10 to 15 minutes. Crystals precipitated and the mixture was vigorously stirred for 2 hours in a sealed vessel.

4. The crystals are suctioned off, with the filter portion not being too dry to dry, and the filter portion is adjusted to contain neither cracks nor slits. At the same time, too much air should not pass through this proportion.

5. Wash the filter in three portions of 15 ml of isopropyl alcohol or acetone, followed by three portions of 20 ml of acetone each. Between the washes, the air passage should not be too large and again the filter portion should be adjusted so that there are no cracks or slits.

6. The crystals are dried under high vacuum at 24-35 ° C for 24 hours.

7. If desired, it is possible to replace the otherwise preferred isopropyl alcohol with acetone, the addition process can also be reversed as necessary, and the solvent added to the stirred D4T solution at half-hour intervals.

Yield D4T = 1 g to 1.1 g

Chemical and physical parameters for D4T sodium salt hydrate.

1. Solubility ´ in water at pH 9,5 to 11 above 300 mg / ml,

2. Persistence of aqueous solution:

week at 50 ° C, 20% balance.

3. Stability in solid state: 1 week at 70 ° C, loss 0

4. Elemental analysis for C- |HH | - |N NO4.HHO calculated: 45.5% C, 5.0% H, 10.6% N, 8.7 Na

H2O for monohydrate: 6.8% found: 45.05% C, 4.89% H, 10.37% N, 8.43 Na

H2O for monohydrate: 6.9%

Mol. Weight: 264.22

5. IR spectrum, see FIG. 1

6. DSC, see FIG. 2

7. TGA, see FIG. 3

8. X-ray diffraction: see FIG. 4

The HPLC ratio is shown in the following table:

table

column: IBM phenyl, 5 µm, 4.5 x 150 nm Mobile phase: 98% 0.015 M NH 4 H 2 PO 4 solution The pH of 7.1 was adjusted with a concentrated solution of ammonia in 2% acetonitrile Flow rate: 0.1 mg / ml Injected volume: 25 microlitres Analysis time: 20 minutes Wavelength: 254 nm temperature: 20-30 ° C Sample concentration: 0.1 mg / ml (water) Retention time: D4T 8 min., Thymine 3 min.

Claims (4)

PATENT CLAIMS A highly water-soluble, stable crystalline salt of 2 ', 3'-dideoxy-2', 3'-dihydrothymidine of the general formula I wherein X represents an organic or inorganic cation. The water-soluble, stable crystalline salt of 2 ', 3'-dideoxy-2', 3'-anhydride according to claim 1, characterized in that X is sodium. A pharmaceutical composition having an antiviral effect, comprising as active ingredient an antiviral effective amount of the salt of claim 1 and a diluent, solid or liquid, suitable from a physiological point of view. 4. A process for producing a highly water soluble, stable crystalline salt of a compound of formula I ', wherein X is an organic or inorganic cation, characterized in that ,, by treatment of ^2', 3'-dideoxy-2 ^', 3'-didehydrothymidine in an inert aqueous solution with the corresponding base, and then the desired salt is crystallized from the solution. Sodium salt 2 ´, 3´-dideoxy-2 ´, 3´- didehydrotymidine