CA2172147A1 - 2',5'-oligoadenylate-2',3'-cyclophosphates - Google Patents

Abstract

The object of the invention is new 2',5' oligoadenylates 2'3' cyclophosphates with the formula:

I

where 0 n 10, particularly 0 to 10, preferably 1 or 2, and medicines containing these as active ingredients, and their applications.

Description

- 2172~7 .

2 ', 5 ' OLIGOADENYLATE 2 ', 3 ' -CYCLOPHOSPHATE

The present invention concerns 2',5' oligoadenylates having a cyclophosphate group at the 3' end and a free OH group at the 5' end, a procedure for producing these compounds, a pharmaceutical preparation containing them and the use of these compounds in treating papilloma-induced medical conditions.
The present invention concerns new chemical compounds, namely 2',5' oligoadenylate 2',3'-cyclophosphates having the general formula:

- I

~O - C~
1- ~

0~ 0 /O
0~o~

o~ /o~
~P o~ C~ 2 O
\1 1/

O O
~Y~o wherein o c n 5 10, particularly 2 0 to 10, preferably 1 or 2.

In particular, compounds where n = 1 or 2 can be advantageously used for medical purposes, namely for 2172~7 .

topical treatment of skin and epithelial lesions caused by papilloma viruses.

Papillomatoses caused by papilloma viruses of the family papovaviridae are widely occurring infections in human and animal populations. More than 60 varieties of human papilloma viruses are currently known.

All of these viruses are similarly structured. The genome has a double-stranded covalent closed ring-form DNA with 8000 base pairs, which codes the virion proteins and other proteins necessary for the intercellular development of the virus. The genome of the papillomaviruses is replicated in the infected cell in the form of episomes (dozens of copies per cell) over the course of many generations. Formation of mature virions does not occur within cells until the final step of differentiation.

In the persistent intracellular state, only the early genes of the papilloma virus genome are expressed. These cause a change in the cell's phenotype and lead to the formation of papillomatoses. Depending on the type of virus and other factors, the virus genome may become integrated into the genome of the infected cells. This in turn may trigger malignant transformation. It is known that a significant number of tumors in humans are the result of malignant transformation by papillomaviruses. They thus represent a result of persistent latent viral infections.

Sexually transmitted anogenital papillomatoses are among the most likely to undergo malignant transformation (see M.
Spitzer, Obest. Gynecol, 1989 vol 73, N3, 303-307; H. zur Hausen, A. Schneider, "The Role of Papillomaviruses in Human Anogenital Cancer" in The Papovaviridae. (ed N.P.
Alzman), 1987, vol 2, 245-263; H. zur Hausen, "Papillomaviruses as Carcinomaviruses" in Adv. in Virus Oneology, (ed G. Klein), 1989, vol 8, 1-26.

21721~7 Since papillomatoses are easily diagnosed pre-cancerous illnesses, the development of many tumors can be prevented by treatment of benign papillomatoses, ie before metamorphosis to a malignant state has occurred in the infected cells.

Currently, the most important methods for treating papillomatoses are surgical removal of the papillomas as well as electro-, cryo-, or laser cauterizing therapy (see "Virus infections: etiology, epidemiology, clinics, pathogenesis and diagnosis", Rep . Col . of Sci en t . Publ i c ., Sverdlovsk, 1985 (in Russian)). Liquid oxygen, acids and their mixtures (saltpeter, oxal and lactic acid, etc) are used for this purpose, but they cause necrosis of surrounding healthy tissue and lead to formation of scars on the site of application, and often lead to recurrence as well as appearance of new papillomas near the site of removal (see S.A. Bashi "Cryotherapy versus podophyllin in the treatment of genital warts", Int. ~. Dermatol, 1985, vol 24, N8, 535-536).

The effectiveness of medical methods in treating papillomatoses using podophyllotoxin and interferon is low and is furthermore accompanied by significant side effects and sequelae, even if therapeutic doses are administered.

The biological activity of podophyllin may be explained by its antimitotic effect, which is comparable to colchicine.
Its use often provokes local reactions (inflammation, allergic contact dermatosis, occasionally erosion of the skin, etc) as well as undesirable after effects such as peripheral neuropathy, tachypnea, hematuria and abortus spontaneus. (see K.R. Beutner "Podophyllotoxin in the Treatment of Genital Human Papillomavirus Infections", S~n1in~rs in Dermatology, 1987, vol 6, N1, 10-18).

The use of interferon in treating papillomatoses has only 2172~ 47 limited effectiveness and doses used for this treatment can lead to suppression of the immune system as well as triggering auto-immune diseases, etc. (see F.G. Bruins, A.J.C. von den Brule, R. Mulinik, G.M.M. Walboomers, C.J.
Meijer, R. Willemze, J. Invest. Dermatol., 1989, vol 93, N4, 544-545; M. Foldvan, A. Moreland, M. Nezei, ibid, 550;
G. Gross, Roussaki, ibid, 553; M. Niimura, ibid, 567.) Synthetic analogs of 2',5' oligoadenylates (2.5 A) are known to display immuno-suppressory activity and have previously been recommended for surgical transplants. It has been stated that oligoadenylates can mediate the effects of interferon with less toxicity and greater effectiveness both specifically and generally (see A.
Kimchi et al, US Patent 4378352(1983)).

The same effect is also achieved with a terminal synthetic 2.5 A containing a morpholine group (see R. Torrence et al, US Patent 4515781 (1985)).
2.5 A analogs with at least three adenosine fragments are known to be active inhibitors or virus protein synthesis in vitro (see Jan M. Kerr et al. US Patent 4,21,P,746 (1980)).

Some synthetic analogs of 2.5 A oligo 3' deoxyadenylates and their derivatives inhibit particularly the infection and transformation of animal cells with herpes simplex and Epstein-Barr-Viruses, but are inactive in the case of already infected or transformed cells (see R.I. Suhadolnik et al, US Patent 4464359 (1984); R.I. Suhadolnik et al, US
Patent 4539313 (1985); R.I. Suhadolnik et al, US Patent 4708935 (1987).

It is also possible to use 2.5 A to treat infectious diseases caused by cytomegalovirus, hepatitis B virus and varicella zoster viruses (see EP-B-121 635 (Au. No. J. Dk.
Fi. Fr. Es.) 1984).

2172~47 A task of research is to make available an effecti~e medicine with selective effect for treating skin and epithelial lesions caused by papillomaviruses.

The purpose of the invention is achieved by producing 2',5' oligoadenylate 2~,3'cyclophosphates having formula I:

N~
I

~ ~ ~
W ~ - I
~O - C~

0~5 0 ~OH
0~0 {~ 2 O

2 0 0~ (~ ~G ~/

o~P ~o-- - - C ~ 2 O
\l 1/
~ ` O O
~0 ~
where 0 5 n 5 10, particularly 2 0 to 10, preferably 1 or 2.

The object of the invention is also the procedure for producing the new compounds, as described in detail below, beginning with poly(A).

These compounds may be produced in a recognizable manner beginning with poly(A~ with irregular 2',5' and 3',5' internucleotide bonds, using a familiar procedure (see A.M.

2172~47 t Michelson in The Chemistry of the Nucleosides and Nucleotides, Academic Press, 1963, 418 and 419) by chemical polymerization of 2'(3') adenosine monophosphate. The subsequent split of the 3',5' bonds in this polymer by ribonuclease from B intermedius (EC.3.1.4.23) leads to a monomer and 2',5' oligoadenylates of varying lengths with a mixture containing a terminal 2',3' cyclophosphate group.

Another two-step procedure may be used to obtain the same result:

1. Division of poly(A) with ribonuclease T2 (or similar ribonucleases) which leads to a series of 2',5' oligoadenylates in which every oligomer represents a mixture of 2',3' cyclophosphate and 3' monophosphate; and, 2. Processing of this mixture with a lOOx excess of BrCN in a buffered aqueous solution, which leads to a transformation of the terminal 3' phosphate group into the 2',3' cyclophosphate group.

These two methods of synthesis may be represented schematically as follows:

poly(A) with irregular 3',5' and 2',5' internucleotide bonds Binase / \ RNAse T2 A>p + A2'p5'(A2'p5' )n A>p Br~ A3'p + A2'p5'(A2'p5' )n A3'p The resulting mixtures of 2',5' oligoadenylates are analysed and the desired oligonucleotides are purified using HPLC according to formula 1.

2',5' oligoadenylates with a terminal 2',3' cyclophosphate 21721 ~7 group as isolated compounds have not been previously described. Both the 2'(3')phosphate groups and the 2',3' cyclophosphate groups in the 2',5' oligoadenylates effectively prevent hydrolysis of these compounds by cellular enzymes. The effectiveness of the 2',3' cyclophosphate analogs as compared to the natural 2',5' oligoadenylates containing the 5' triphosphate group may be explained by the greater potential for cell permeation because of a lower charge and the resistance to hydrolysis with cell enzymes, such as phosphodiesterases.

The 2',5' oligoadenylates to be used in the inventlon can be dissolved in water or aqueous solutions of neutral salts and applied to skin lesions once or twice daily for 2 weeks (usually flat warts and sole warts, condylomas etc). The concentration of the active ingredient is 10-4 to 10-7 M.

This treatment of the condylomas stops their growth. There was no new formation and, in most cases, the old condylomas regress within 4 to 6 weeks.

In the case of ordinary warts, the papules generally flatten out towards the end of the first week and disappear completely 2 to 4 weeks after the beginning of treatment.
Patients with flat warts were completely cured 1 month after the beginning of treatment.

In the course of treatment of the papillomas, new formations shrunk after 1.5 to 2 weeks while smaller papillomas disappeared. Complete reduction of skin lesions occurred within 1 month. There was not a single instance of scarring. The healing was also not accompanied by toxic-allergic reactions or other side effects.

The concentration of active oligoadenylates in the treatment solutions is two orders of magnitude greater than for interferon induced cells, but the total quantity of 2172~47 solution applied generally falls under 1.0 ml. Even if all the oligoadenylates are absorbed, the resulting average concentration in cells and body fluids (blood, urine, etc) is far below that in non-induced cells. The concentration of compounds used will be higher only temporarily (immediately after application) than that of their natural analogs in normal cells, and that only in tissue immediately surrounding the area of application.

The 2',5' oligoadenylates are easily degraded by nucleases and phosphatases inside and outside of cells in the organism. The end products include adenyl acid and adenosine, which represent ordinary cell metabolites whose average concentration in cells is under 10-3 M.
Both oligoadenylates corresponding to ormula I and mixtures containing them may be used in treating skin and epithelial lesions induced by papillomaviruses.

Topical application of low dosages of 2',5' oligoadenylates based on this invention to treat papillomatoses was widely ef~ective, and no negative skin reactions or systemic side effects were observed. The result of treatment of the lesions was complete reduction in more than 80~ of patients. At the end of a 3-month observation period there was no evidence of recurrence.

The preparation based on the invention can be administered in various forms appropriate for topical application.
These are produced by careful mixing or dissolving of the individual compounds or their mixtures with a pharmaceutically compatible carrier using standard techniques. Depending on the desired form of preparation for the application (external skin, mucous membrane tissue, etc), the form of the carrier may vary greatly. The most diverse pharmaceutical media can be used to produce preparations, for example liquid carriers such as water, 2~72~47 .

dimethyl sulfoxide with or without alcohols, glycols etc or pomades, ointments and plasters. For convenience, it is especially useful to arrange these preparations in single-dose units. The expression "single-dose unit" refers to physically discrete units of which each one contains a specific quantity of the active ingredient calculated to achieve the desired therapeutic effect when combined with the required pharmaceutical carrier. The corresponding dosage for a single application in treating papillomatoses should be 10-9-10-8 M of active ingredient (n = 1 and/or 2) per papula (3-5 mm in diameter). The total duration of treatment is up to 30 days with daily application.

The following examples illustrate the production of oligonucleotide mixtures and individual 2',5' oligoadenylates.

Chemical-enzymatic synthesis, purification and analysis of 2',5~-oligoadenylates All reactions are carried out at room temperature.

a) Synthesis of poly(A):

0.9 g (2.5 mMol) of adenosine 2'(3') monophosphate in H+
form and 1.2 ml (2.6 mMol) of tri-n-octylamine are dissolved in 30 ml of methanol/ethanol (1:1) and the solution is stirred for several hours. Then the undissolved portions are filtered out using a glass filter, and the filtrate is evaporated using a rotary evaporator until dry. The resulting solid is then dissolved in 10 ml abs. dioxane and evaporated until dry using a rotary evaporator. Both procedures are repeated twice. Then the resulting solid is dissolved in 5 ml abs. dioxane and 0.77 ml (3.75 mMol) of diphenylphosphorylchloride is dripped onto it while the mixture i~ stirred with a magnetic stirring device. Then 3.3. ml (7.5 mMol) tri-n-octylamine 21721~7 are added. The resulting mixture is stirred for an hour after which 0.77 ml of diphenylphosphorylchloride and 3.2 ml tri-n-octylamine are added, and the mixture is stirred for 4 more hours. Then the reaction mixture is poured into 5 volumes of hexane/ether (4:6) while being stirred. The sediment is then filtered off using a glass filter, washed with the same mixture and then with ether and dried in a vacuum. The result is a white powder of polyadenylate with irregular 2',5' and 3',5'-internucleotide bonds. The general formula of the mixture is (A2'(3')p-)~A>p, where n=10.

The dry polymer mixture is then dissolved in 12 ml of water and the pH is adjusted to 9.3 by adding a conc. ammonia solution. Then 3 volumes of ethanol are added and the pH
is adjusted to 3.0 by adding 5 M HCl. The sediment which forms when the mixture is stored at -18C is centrifuged off, washed with 75~ ethanol and dried in an air-stream.
A considerable portion of the monomer remains in the supernatant.

b) Selective splitting of the 3',5' internucleotide bonds by splitting with binase:

The precipitate resulting from a) is dissolved in 40 ml H2O
and the pH is adjusted to 7.0 with a 3 M solution of tris-base, after which 2 ml of a solution of Bacillus intermedius RNAse (binase, E.C.3.1.4.23) (150 E/mg) is added and then stirred for 10 to 12 hours. The enzyme is then extracted using the same volume of chloroform/isoamyl alcohol (24:1). The resulting aqueous phase contains a mixture of 2',3' cyclophosphates of adenosine and 2',5' oligoadenylates.

c) Isolation of the individual compounds:

The procedure for separating the individual components is 21721 ~7 based on ion exchange chromatography using DEAE spheron 1000 in HCO3- form (16 x 600 mm, 120 ml). The enzymatic division product of poly(A) is deproteinated and then concentrated in a rotary evaporator 8 to 10 times. 10 volumes of ethanol are added and the mixture is left at -18OC for 12 hours. A~ter centrifuging (10 to 20 min at 3000 rpm) the sediment is dissolved in water and loaded onto the column (optical thickness 25,000 to 50,000 E at 260 nm).
After the column is washed with water and 0.05 M triethyl ammonium bicarbonate (pH 8.0) the products are eluted at a linear gradient of this salt (0.1 to 0.8 M, total volume 1 L). The fractions containing the individual compounds thus separated are evaporated until dry in a rotary evaporator and lyophilated to completely remove the buffer components.
HP~C is used for the final cleaning of the individual compounds as explained below (a coating of ca. 2000 E
optical thickness on the semi-preparative columns).
Desalting the solution is achieved by adsorption of a 10 to 20x diluted solution on small DEAE columns, washing with water, elution with a small quantity of 1 M triethyl ammonium bicarbonate and lyophilation.

d) Cleaninq and analysis of the 2',5' oliqoadenylate with HPLC chromatoqraphy:

Ion exchange chromatography is performed with a NH3 diasorb column (8 ~m, 4 x 150 mm for the analysis and 10 ~m, 9.2 x 250 mm for the final preparative cleaning); linear gradient; elutrient A - 20~ MeOH; B - 2M AmAc, 20~ MeOH, 2~
B per mixture; fluidity (flow-through time) - 0.7 ml/min for the analytic column and 4 ml/min for the preparative (fig. 1 - 3). Detection is with a W monitoring device at 260 nm.
On the basis of the optical thickness of 260 nm the mixtures contain 40 to 50~ monomer, ca. 20~ to 30~

217~1~7 .

diadenylate, ca. 5~ to 15~ triadenylate, 2~ to 8~
tetraadenylate and 2~ to 7~ of higher oligoadenylates. The average molar extinction coefficient was 15 x 103 per adenosine residue, 36.8 x 103 for the trimer and 45.8 x 103 for the tetramer.

e) Determining the comPOsitiOn of individual compounds:

Each compound was kept at pH 1.0 (1 hour at 370C) to open the cyclophosphate group, dephosphorylated with bacterial alkaline phosphatases and subjected to alkaline hydrolysis of the internucleotide bonds (0.3 M NaOH, 48 hours at 200C). The relation of the end products (adenosine to adenosine 2'(3') phosphate was achieved by HPLC. The actual results agree closely with those given above:
Ado:AMP = 1:1 for the dimer, 1:2 for the trimer and 1:3 for the tetramer. The standard deviation was less than 5~.

On the basis of their HPLC mobility and NMR spectra (31p and lH), the compounds produced by the acid opening of the 2',3' cyclophosphate group were identical to familiar 2'(3') phosphates of the corresponding oligoadenylates. On the other hand, the resulting 2'(3') phosphates were quantatively converted into 2',3' cyclophosphates of the corresponding oligoadenylates in an aqueous solution at room temperature due to the effect of the BrCN (lOOx molar excess).

f) Determining the internucleotide bond type:
The treatment of the 2',3' cyclophosphates of the individual 2',5' oligoadenylates with fresh binase operates under conditions which lead to complete cleavage of 3',5' polyadenylic acid cyclophosphate produces no change in the HPLC separation profile and in the 31p NMR spectra.

Only peaks corresponding to the terminal cyclophosphate 217~1~7 group (20 to 21 ppm) and the 2',5'-internucleotide phosphate (0.02 to 0.4 ppm) were determined in the 31p NMR
spectra, at a relation of 1:1 for the dimer, 1:2 for the trimer and 1:3 for the tetramer. The standard deviation was less than 2~. The 3',5' bond (less than 1~
internucleotide phosphate) has been demonstrated only for the tetramer.

Oligoadenylates are colorless compounds readily soluble in water (up to 10-2M), dimethylsulfoxide, aqueous ethanol or glycerol. They remain dissolved in a neutral aqueous solution at 40C for several months and indefinitely when frozen in solution (-200C) or in a lyophilized state.

Pharmacoloqical ExamPles Clinical research of the pharmaceutical preparation has been conducted on papillomatose patients. Treatment was with Na- or triethyl ammonium salt of the corresponding compound, which had been diluted to the required concentration with 0.1 ml NaCl. The concentration of the effective compound in the final solution achieved using its optical thickness at 260 nm following the molar extinction coefficient procedure described above. The results are described below. The examples serve to illustrate the invention, but do not limit it.

Example 1 Clinical test of 2',5' triadenylate 2',3' cyclophosphate (n=l, AIII).

Diagnosis of female patient M. (1958): 4 sharp-edged condylomas located in the perineal region (d=l to 2 mm, h = 2 to 8 mm), skin-colored, raw, elastic and sometimes painful. Accompanying illness: colpitis.

21721 ~7 Daily application of ca. 50 ~m AIII(10-4M) per condyloma. On the fourth day all condylomas showed a wrinkled surface; by the eighth day they had completely disappeared. No recurrence was observed after 8 weeks.

Diagnosis of female patient P. (1950): 14 condylomas located in the perineal region (d=2 to 8 mm, h = 2 to 5 mm), elastic, skin-colored and often painful.

Daily application of 50 ~m AIII(10-4M) per condyloma for two weeks. By the sixth day all condylomas had shrunk by one-half to one-third. By the 10th day 8 condylomas had completely disappeared without leaving any trace on the skin. The remaining 6 condylomas were still present and 3 to 4 weeks after treatment regained their original size.
Treatment was not continued further. No changes were observed 10 weeks after the end of treatment (no recurrences, no formation of new condylomas).

Diagnosis of female patient C. (1958): a sole wart on the underside of the big toe (d=5 mm, h 3 mm), compact, same color as surrounding tissue, with rough outer surface and extremely painful when walking.

Daily application of 50 ~m AIII(10-4M) per wart. On the sixth day the wart had grown softer and the surface of the wart was rubbed away mechanically. By the tenth day the wart had completely disappeared and walking did not cause any pain. At a checkup after 12 weeks no recurrence was observed. The affected skin surface area was indistinguishable from the surrounding tissue.

Diagnosis of female patient C. (1926): 7 papillomas were found on the front and right side of the throat, 2 large (d=3 and 2 mm, h = 2.5 mm, dark brown) and 5 smaller (d =
0.8 to 1.5 mm, h = 0.8 to 1.5 mm, skin-colored), The papillomas had appeared in 1982 during menopause.

2172~7 Daily application of ca. 50 ~m AIII(10-4M) per papilloma for two weeks. On the fifth day the smaller papillomas had turned pale, shrunk and flattened out. No further changes were ob~erved. Two to 3 weeks after the end of treatment the papillomas had regained their original form and size.

Example 2 Clinical test of 2',5' tetraadenylate 2',3' cyclophosphate (n=2, AIV).

Diagnosis of female patient S, 27 years old: ordinary warts on the stomach, 3 cm underneath the navel, grey in color, protruding, diameter 2 to 3 mm). The warts were treated daily with 1 to 3 drops of AIV(10-5M). On the 7th to 10th day after beginning of treatment all the warts had shrunk and flattened out. Three weeks after the end of treatment one of the warts had completely disappeared and four weeks after the end of treatment all the others. No scar-like changes in the skin.

Seven other patients with numerous warts, condylomas (six patient~), ordinary warts (three patients) and unidentified warts (four patients) were treated daily for two weeks with an aqueous solution (10-sM) of AIV. The condylomas were found on the external genitalia and on the breast, the warts on the wrist, body and legs.

In most cases the condylomas and warts (especially the former) shrank after 6 to 9 day treatment. 1 to 2 weeks after the end of treatment or during treatment three patients were already completely free of condylomas and two showed no more ordinary warts. One patient was completely free of all six condylomas under the armpit about 6 weeks after the end of treatment. In two cases, small condylomas (d < 3 mm, total 11) on the external genitalia disappeared during or after treatment while larger ones in the same 2172~7 area (d > 5 mm, two in the first case, three in the second) regained their original size and form 2 to 6 weeks after treatment. Two of the six unidentified warts disappeared 2 to 3 weeks after treatment, but the others showed no reaction. Negative reactions, traces on the skin or recurrences were not observed in a single case during treatment or 8 to 12 weeks afterwards.

Example 3 Clinical test of mixture A (mixture of 2',5' oligoadenylate 2',3' cyclophosphate (n>0). Two patients were tested, one with three ordinary warts (3 to 4 mm) on the neckand the other with two condylomata acuminata on the inner side of the leg. Each wart was moistened daily with 1 to 2 drops of 10-4M aqueous solution of mixture A. On the 9th day of treatment all the ordinary warts had disappeared. One small condyloma disappeared after 7 days of treatment, another three weeks after the end of treatment, ie five weeks after the beginning of treatment.

The results achieved show clearly the high effectiveness of the compounds under research as well as the procedure for treating skin and epithelial lesions caused by human papillomaviruses. Treatment of the papillomaviruses with 2',5' oligoadenylate was not accompanied in a single case by painful or inflammatory reaction nor by a subjective or objective worsening of condition.

The high clinical effectiveness of 2',5' oligoadenylate at very low dosages and the absence of local reactions and systemic side effects as well as lack of recidivism demonstrate the advantages of the compounds under consideration for treating papillomatoses.
Similar results in treating papillomatoses were also achieved using already familiar compounds, ie 2',5' 217~147 .

oligoadenylates with natural adenosine residues and 2'(3') phosphate groups (series B) or free 2' and 3' hydroxyl groups (series C) on a 3-terminal adenosine residue. In these cases both isolated compounds, for example trimers and tetramers or their mixtures with other oligomers, (trimers B and C, tetramers B and C, mixtures B and C) proved to be widely effective in the treatment of external papillomaviruses.

Description of the figures Fig. 1:
HPLC analysis of mixture A (2',5' oligoadenylate 2',3', cyclophosphate. Column: diasorb NH2, 4 x 150 mm. Mobile phase: A - 20~ CH30H; B - 2M Ac0NH4 in 20~ CH30H; Fluidity:
0.7 ml/min; 0'-2' - 1~ B, 2'-14' - 0.5~ B/min, 14'-50' - 2 B/min. Detection at 260 nm. Composition of the mixture corresponding to absorption at 260 nm: 23~ monomer (8.7 min), 22.5~ dimer (17.5 min), 14~ trimer (23 min), 6.8 tetramer (26.8 min).

Fig. 2:
HPLC analysi~ of the purified 2',5' trimer (A) and tetramer (B) 2',3' cyclophosphate. Column, composition of the mobile phase and fluidity as in fig. 1, gradient - 2~ B/min.

Claims (3)

Claims:

1. 2',5' oligoadenylate 2',3' cyclophosphates with the general formula:

I

wherein 0 n 10, particularly 0 to 10, preferably 1 or 2.

2. A method for producing the compounds of Claim 1 distinguished by the identifiable manner in which adenosine 2'(3') phosphate polymerizes to poly(A) with irregular 3',5' and 2',5' internucleotide bonds and this polymer is treated with RNAse from B intermedius (E.C.3.1.4.23).

3. A pharmaceutical preparation for treating benign or precancerous skin and mucous membrane lesions caused by papillomaviruses. The preparation contains one of the compounds in Claim 1 or mixtures in which it is the active ingredient, combined with a pharmaceutically appropriate carrier or a solvent.