WO1996014841A1

WO1996014841A1 - Antiviral and antitumor pharmaceutical compositions

Info

Publication number: WO1996014841A1
Application number: PCT/US1995/014834
Authority: WO
Inventors: Gerhard Sauer; Eberhard Amtmann
Original assignee: Ct-Holding S.A.
Priority date: 1994-11-14
Filing date: 1995-11-13
Publication date: 1996-05-23
Also published as: AU4159596A

Abstract

This invention relates to compositions comprising a pharmaceutically effective amount of a xanthate compound and an adjuvant in a lipid-based or steroid-based carrier which are useful for the treatment of viruses and tumors. In particular, the compositions of the invention are effective for the treatment of HSV.

Description

ANTIVIRAL AND ANTITUMOR PHARMACEUTICAL COMPOSITIONS FIELD OF THE INVENTION The invention relates broadly to pharmaceutical compositions for the treatment of viral diseases and tumors. More specifically, the invention relates to compositions containing xanthate compounds and activity enhancing adjuvants in lipid- or steroid-based carriers.

BACKGROUND OF THE INVENTION Viral diseases and tumorigenic diseases are a major cause of mortality in man and animals. Lack of success in prior treatments is due primarily to the fact that both diseases are closely associated with the affected cells, e.g. replication of viruses is driven by the host cell biomechanics and tumor growth develops from preexisting tissue.

Of particular medical concern is the herpes simplex virus (HSV) . HSV is a serious and widespread health problem of epidemic proportion, due in large part to the proclivity of the virus to establish a latent infection and thereafter to produce spontaneous recurrent disease. Dr. Jonas Salk, in Prospects for the Control of AIDS by Immunizing Seropositive Individuals. Nature (London) Vol. 327 (1987) pgs. 473-476, estimated that up to 50% of teenagers, from a range of socioeconomic backgrounds and demographic locations, will be HSV seropositive by the age of 16. An HSV seropositive response indicates a past history of either HSV type 1 (HSV-1) or type 2 (HSV-2) infection.

An important obstacle to the development of antiviral and antitumor treatments is the development of a suitable delivery system that can target therapeutic agents in effective concentrations to sites of virus replication or tumor growth.

U.S. Patent No. 4,602,037 issued July 22, 1986 to Scherm et al. describes the antiviral and antitumor properties of xanthates. The disclosure of U.S. Patent No. 4,602,037 is hereby incorporated by reference.

The xanthates described in U.S. Patent No. 4,602,037 fall within the scope of formula I: S (i)

II

R^α O S — R²

wherein R¹ represents norbornyl, tricyclodecyl (including adamantyl) , benzyl, straight or branched C₃-C₂₀-alkyl, C₃- C ₀-cycloalkyl, furyl, pyridyl, or guinuclidinyl or the aforesaid straight or branched C₃-C₂₀-alkyl optionally substituted by hydroxy, C₁-C₄-alkoxy, or by halogen, or the aforesaid C₃-C₂₀-cycloalkyl optionally substituted by hydroxy, C₁-C₄-alkoxy, C₂-C₄-alkyl, or halogen; and wherein R² represents a monovalent or multivalent metal atom, straight or branched C^C₈-alkyl, which may optionally be substituted by hydroxy, C₁-C₄-alkoxy, amino, C₁-C₄-alkylamino, (C₂-C₄-alkyl)₂-amino, (C₂-C₄-alkyl)₃- ammoniu , or halogen, or 2,3-dihydroxypropyl or ω- hydroxy-(C₂-C₄-al oxy)-methyl. Sodium or potassium benzylxanthate, cyclohexylxanthate, l-adamantylxanthate, 8(9)- tricyclo[5.2.1.0^2,6]-decylxanthate, 2-endo or exo- bicyclo[2.2.1^1*4]-heptylxanthate, cyclododecylxanthate, n- dodecylxanthate, or 4-isobornyl-cyclohexylxanthate are compounds which have been found to be particularly effective.

Numerous xanthates of such structure have been tested for their antiviral characteristics. Sauer et al. , ^MDNA and RNA Virus Species are Inhibited by Xanthates, A Class of Antiviral Compounds With Unigue

Properties," Proc. Natl. Acad. Sci., Vol. 81 (June 1984) pp. 3263-3267 discuss the testing of the following compounds: D416: Cyclohexyl-oxy-dithioformic-acid sodium salt

D435: Cyclododecyl-oxy-dithioformic-acid potassium salt

D436: Dodecyl-oxy-dithioformic-acid potassium salt D442: Toluoyl-oxy-dithioformic-acid sodium salt

D607: Cyclohexyl-oxy-dithioformic-acid-methyl ester

D609: Tricyclo[5.2.1.0^2*6]-decy1-oxy- dithioformic-acid potassium salt

D611(endo) : 2-endo-bicyclo[2.2.1]-heptyl-dithioformic- acid potassium salt D611(exo) : 2-exo-bicyclo[2.2.1]-heptyl-dithioformic- acid potassium salt D614: Cyclohexyl-oxy-dithioformic-acid dimethylglycl-ester All of these compounds exhibited antiviral activity. In particular, D435, D609, and D611 were found to be very efficient virus inhibitors. It is also known that certain compounds can be used as adjuvants to increase the effectiveness of therapeutic compounds. Adjuvants, by themselves, do not exhibit therapeutic qualities, but when combined with therapeutic compounds enhance their effectiveness. U.S. Patent No. 4,851,435 issued July 25, 1989 to Sauer et al. describes using xanthates, as described in U.S. Patent No. 4,602,037, in conjunction with certain adjuvants. The disclosure of U.S. Patent No. 4,851,435 is hereby incorporated by reference. The adjuvants described in U.S. Patent No.

4,851,435 are ionic compounds having both lipophilic and hydrophilic groups. The compound is desirably one wherein the lipophilic group is a straight or branched aliphatic group with 6 to 18 carbon atoms and the hydrophilic group comprises 1 or 2 carboxyl and/or 1 or 2 sulphate, sulphonate, or phosphate groups. Advantageously, the adjuvant compound is an aliphatic mono or dicarboxylic acid, or fluorinated derivative thereof, or an aliphatic mono or disulphate, mono or disulphonate, or mono or diphosphate, and has 6 to 18 carbon atoms, or, such a compound having 1 or 2 ether and/or amide groups. Pharmaceutically acceptable salts of all the above compounds may be used.

Preferably the adjuvant compounds are aliphatic monocarboxylie acids with 9 to 13 carbon atoms or fluorinated derivatives thereof, or fatty alcohol sulphates, phosphates, ether phosphates, ether sulphates, alkane sulphonates, olefinic sulphonates, sulphocarboxylic acid esters or glyceride sulphates having 8-18 carbon atoms. Naturally occurring fatty acids or fatty alcohol sulphates with 8 to 18 carbon atoms are also effective. The most advantageous adjuvant compounds are the sodium and potassium salts of decanoic acid, undecanoic acid, dodecanoic acid, deoxycholic acid, dodecyl sulfate, or dodecylphosphonic acid, or pharmaceutically acceptable salts thereof.

A number of the above-discussed adjuvants have been tested for their antiviral enhancing characteristics. Music et al., "Mechanistic Aspects of the Synergistic Antiviral Effect of Xanthates and Monocarbonic Acids," Biochemical Pharmacology, Vol. 38, No. 12 (1989) pp. 1941-1945 discusses the testing of the adjuvants with the xanthate D609 (8(9)- tricyclo[5.2.1.0^2,6]-decyl xanthate). Fatty acids of eleven to fourteen carbon atoms (undecanoic acid, dodecanoic acid and myristic acid) were found to be effective adjuvants while shorter (6 carbon) and larger (18 carbon) monocarboxylic acids were shown to lack activity enhancing properties.

The xanthate and xanthate/adjuvant compositions have been found to have effective antiviral and/or antitumor activity if the requisite concentration is at least 2.5 wt% xanthate in a topical ointment and at least 10 mg/ml xanthate in a solution for intravenous or subcutaneous injection. When using xanthate/adjuvant compositions for topical application, it has been found that experimental animals can only tolerate a concentration of about 1 wt% xanthate in ointment. A concentration of 3 wt% xanthate causes skin irritation and a concentration of 5 wt% xanthate causes necrotic destruction of tissue. The 1% concentration is much too low to achieve the desired therapeutic effect.

When a xanthate/adjuvant composition was prepared as a solution for intravenous or subcutaneous injection, concentrations above 1 g/ml could not be tolerated by experimental mice without severe destruction of tissue. This concentration also is well below the levels necessary to achieve the desired therapeutic effect.

The challenge in producing a therapeutically effective composition is to develop an effective carrier to reduce the toxicity of the xanthates such that the antiviral and antitumoral xanthates can be delivered in effective concentrations to sites of virus replication or tumor growth.

OBJECTS OF THE INVENTION It is thus a primary object of the invention to provide a composition capable of delivering an effective amount of a xanthate compound plus adjuvant to sites of virus replication or tumor growth for combating said viruses or tumors. It is a further object of this invention to provide a carrier for a xanthate plus adjuvant composition which reduces the toxicity of the active components.

It is still a further object of this invention to provide a xanthate compound plus adjuvant composition in a carrier which can be used in topical applications or in intravenous or subcutaneous injections.

SUMMARY OF THE INVENTION These and other objects of the invention are achieved in compositions comprising a pharmaceutically effective amount of a xanthate compound and an adjuvant in a lipid-based or steroid-based carrier. These compositions are useful for the treatment of viruses and tumors. In particular, the compositions of the invention are effective for the treatment of HSV.

In preferred embodiments, the invention includes, as the active components, a xanthate which has antiviral or antitumoral activities, such as those described in U.S. Patent No. 4,602,037, and, an ionic adjuvant containing both a lipophilic and hydrophilic group which has been shown to enhance the activity of the xanthate, such as those described in U.S. Patent No. 4,851,435, and, as a carrier, cholesterol.

A particularly preferred composition includes the active components (a) a sodium or potassium salt of 8(9)-tricyclo[5.2.1.0^2*6]-decylxanthate (D609) , and (b) a sodium or potassium salt of lauric acid (KC12) , also known as dodecanoic acid, and in a liposome comprised of cholesterol.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing the irritating effects of D609-containing ointments.

FIG. 2 is a graph showing the irritating effect of D609-containing ointments, in cholesterol and in free- form, respectively, when topically administered to mice. FIG. 3 is a graph showing the irritating effect of D609-containing solutions, where the D609/KC12 is in free-form and in cholesterol, respectively, when subcutaneously injected in mice.

FIG. 4 is a graph of the dose-response curves of free-form D609/KC12, and D609/KC12 in cholesterol, respectively, when used to treat monkey kidney cells

(Rita) infected with herpes simplex virus type 1 (HSV-1) .

FIG. 5 is a graph showing the response of tumors in mice to D609/KC12 in cholesterol over a two week period. DETAILED DESCRIPTION OF THE INVENTION

The objects of the invention are achieved by compositions comprising an effective amount of a xanthate compound and an adjuvant in a lipid- or steroid-based carrier.

Broadly, the compositions include a xanthate compound of formula I:

S (I)

I

R¹ — 0 — C S — R²

wherein R¹ represents norbornyl, tricyclodecyl (including adamantyl) , benzyl, straight or branched C₃-C₂₀-alkyl, C₃- C₂₀-cycloalkyl, furyl, pyridyl, or quinuclidinyl or the aforesaid straight or branched C₃-C₂₀-alkyl optionally substituted by hydroxy, C₂-C₄-alkoxy, or by halogen, or the aforesaid C₃-C₂₀-cycloalkyl optionally substituted by hydroxy, C₂-C₄-alko y, C₂-C₄-alkyl, or halogen; and wherein R² represents a monovalent or ultivalent metal atom, straight or branched C₂-C₆-alkyl, which may optionally be substituted by hydroxy, C₂-C₄-alkoxy, a ino, C₂-C₄-alkylamino, (C₂-C₄-alkyl)₂-amino, (C₂-C₄-alkyl)₃- ammonium, or halogen, or 2,3-dihydroxypropyl or ω- hydroxy-(C₂-C₄-alkoxy)-methyl; an adjuvant compound, generally an ionic compound having both lipophilic and hydrophilic groups, wherein the lipophilic group is a straight or branched aliphatic mono or dicarboxylic acid, or fluorinated derivative thereof, or an aliphatic mono or disulphate, mono or disulphonate, or mono or diphosphate, having 6 to 18 carbon atoms, or such a compound having 1 or 2 ether and/or amide groups, and wherein the hydrophilic group comprises 1 or 2 carboxyl and/or 1 or 2 sulphate, sulphonate, or phosphate groups, or pharmaceutically acceptable salts thereof; and a lipid-based or steroid-based carrier. The preferred embodiment of the invention is the sodium or potassium salt of 8(9)-tricyclo[5.2.1.0^2,6]- decylxanthate (D609) mixed with the sodium or potassium salt of lauric acid, also known as dodecanoic acid (KC12) in cholesterol.

The carriers of the invention are lipid-based or steroid-based carriers. The lipid-based carrier are amphipathic lipids including phospholipids (e.g. lecithin, phosphatidylcholine, phosphatidylserine, phosphatidylinositol) , glycolipids (e.g. ganglioside) , sphingolipids (e.g. sphingomyelin) . The steroid-based carriers include stearyla ine, chondrillasterol, a,β, y sitosterol, cholesterol and its salts, and cholesterol derviatives such as cholestanol and cholanic acid. The carrier must be pharmaceutically acceptable and compatible with the active components, xanthate and adjuvant. The active components may be suspended within the carrier, may form micelles therewith, may be micro- emulsified within the carrier or may be encapsulated within a liposome structure.

Liposomes are generally spherical bilayer lipid structures having aqueous interiors. They are prepared by suspending a polar lipid film, such as a phospholipid, in an aqueous solution. They have basically the same structure as do cell membranes and therefore have many properties similar to those cell membranes. Liposomes are easy to manipulate mechanically, their compositions can be varied, and, they have the ability to encapsulate or complex a wide variety of hydrophilic or lipophilic biologically active compounds. Liposomes can be formed from a variety of substances, such as phospholipids, glycolipids, sphingolipids, and steroids. Numerous methods exist to make liposomes. These include sonication, ultrasonication, injection, centrifugation, entrapment by freezing, and dehydration/rehydration.

Of particular importance as a carrier is the steroid cholesterol. Cholesterol is the major constituent of animal tissue, and although cholesterol is almost entirely hydrocarbon in composition, it is amphipathic because it contains a hydroxy1 group that interacts with water. This characteristic makes cholesterol a particularly effective carrier for therapeutic compounds. The active components may be micro-emulsified in the cholesterol, forming a micelle therewith or be microencapsulated in a liposome thereof. Surprisingly, it has now been found that when the xanthate/adjuvant mixtures are incorporated into cholesterol, concentrations of up to 12.5 wt% D609 in topical ointments and up to 50 mg/ml D609 in solutions for injection were tolerated by experimental mice. Surprisingly, it was also found that the incorporation of the active components in cholesterol had no adverse effect upon the antiviral activity of the xanthate/adjuvant mixture.

Preparation of Therapeutic Compositions A therapeutic composition can be prepared by mixing approximately equal amounts of D609 and KC12 with cholesterol. The preferred ratio of cholesterol to D609/KC12 mixture is about 1:1. Sterile, pyrogen-free water is added to the D609/KC12/cholesterol mixture to form a suspension. The suspension is then sonified and centrifuged to form an emulsion. The term emulsion is used herein but may be understood to cover emulsions, micelles, liposomes and other complexations of the active compounds in the cholesterol. The emulsion is immediately frozen and lyophilized.

It has been found that solution emulsions of D609/adjuvant mixtures in cholesterol, in a ratio of one part xanthate, one part adjuvant and two parts cholesterol, can be prepared for intravenous or subcutaneous injection by addition of a buffer solution (aqueous NaCl) . Such solution emulsions may contain concentrations of D609 up to 50 mg/ml. Solution emulsions containing higher concentrations were too viscous to be effectively used for injections. Ointments for topical treatment can be prepared with liquid paraffin and vaseline. These contain the active components in a ratio of one part xanthate, one part adjuvant and two parts cholesterol. Concentrations of D609 up to 12.5 wt% in the ointment can be obtained. The upper limit of concentration is a physical limitation. The ointment becomes too viscous at higher concentrations to be effectively used for topical application. It has been found that an effective xanthate to adjuvant ratio is one to one. However, the xanthate to adjuvant ratio can vary from one part xanthate per ten parts adjuvant to ten parts xanthate per one part adjuvant. Such mixtures, when incorporated in the carriers of the invention, will exhibit effective antiviral and/or antitumor activity.

It has also been found that the ratio of xanthate/adjuvant mixture to cholesterol may be broadly from one part xanthate/adjuvant mixture to 0.25 part cholesterol to one part xanthate/adjuvant mixture to 4 parts cholesterol.

When administered in a cholesterol carrier, the xanthate/adjuvant mixture retains its therapeutic effectiveness, and is surprisingly and significantly less toxic. Most surprising was the discovery that the xanthate alone cannot be effectively incorporated into cholesterol without the adjuvant.

The following examples are presented to illustrate and provide a better understanding of the invention.

EXAMPLE 1 Incorporation of D609 in Cholesterol With and Without Lauric Acid D609 (without KC12) in cholesterol was prepared by mixing 400 milligrams of D609 and 400 milligrams of cholesterol suspended in a 50 ml plastic vial in 40 ml distilled water. D609 (with KC12) in cholesterol was prepared by mixing 400 milligrams of D609, 400 milligrams of KC12, and 800 milligrams of cholesterol suspended in a 50 ml plastic vial in 40 ml distilled water. Both suspensions were placed in an external ice bath and sonified with a Branson Sonifier B15 at a maximum energy output with 40% duty cycle for 15 minutes to form an emulsion.

Free D609 was separated from the suspensions by ultrafiltration (Amicon micro ultra-filtration vials, exclusion size 30kd, Sorvall centrifuge SS20 rotor at 5000 rpm for 15 minutes) after 1:10 dilution with phosphate buffered isotonic salt solution (pH 7.0). Five μl of each sample were applied to a Silia Gel 60 plate and the plate was run in acetonitrile. Aliquots (1-7 μl) of a solution containing 1 mg/ml D609 served as position markers and for quantitative determination.

D609 spots were visualized under ultraviolet light (300nm) . The absorption of each spot was quantitated with the aid of a computerized video system. The resulting analysis indicated that in the presence of KC12, 87% of D609 was incorporated in the cholesterol. However, in the absence of KC12, only 1% of D609 was incorporated.

Additional experiments were run to confirm that the presence of KC12 was necessary for effective incorporation of D609. The confirmatory results are indicated in Table 1.

TABLE 1

D609 KC12 Cholesterol Amount of cone, cone. cone. incorporated (mg/ml) (mg/ml) (mg/ml) D609 (%)

50 0 200 0.8

50 20 200 35

50 50 200 81

20 50 200 60

10 50 200 45

50 0 500 6.8

45 5 500 76.3

35 15 500 83.5

25 25 500 83.3

15 35 500 76.6

5 45 500 71.0

EXAMPLE 2

Preparation of Compositions Containing D609/KC12 in Cholesterol For Therapeutic Test Purposes

The composition was prepared by mixing 2 grams of D609 and 2 grams of KC12 with 4 grams of cholesterol and sterile, pyrogen-free water was added to make up a final volume of 40 ml of suspension. The suspension was placed in an external ice bath and sonified with a

Branson Sonifier B15 at a maximum energy output with 40% duty cycle for 15 minutes to form an emulsion. The emulsion was then centrifuged at about 3000 Gs for approximately 10 minutes. After centrifugation, the volume of the supernatant was adjusted to about 40 ml by the addition of distilled water. The emulsion was immediately frozen and lyophilized.

Solution emulsions for intravenous or subcutaneous injection were prepared by the addition of a saline buffer solution (0.9% NaCl) to the D609 emulsion. Solution emulsions with up to 50 mg/ml of D609 can be prepared. Ointments for topical treatments were prepared by mixing the solution emulsions with liquid paraffin and vaseline. Concentrations of D609 of up to 12.5 wt% were obtained.

EXAMPLE 3 Assessment of the Irritating Effects of D609-Containing ointments

In order to assess the irritating potential of D609-containing ointments, ointments containing various amounts of D609 in vaseline were administered to the each of the shoulder regions of four female mice (strain NMRI Nu/Nu, 8 weeks old) . The degree of irritation was scored beginning 16 hours after treatment according to the following stages: no effect (0), slight redness (0.5), redness (1.0), inflammation (1.5), and visible tissue damage (2.0) .

When examined 16 hours after treatment, the ointment containing 1.56 wt% free D609 had no effect and was given an irritation score of 0. The ointment with 3.13 wt% free D609 caused slight reddening in 2 sites, reddening in 3 sites, tissue destruction in 1 site, and had no effect in 1 site, and was given an irritation score of 6. The ointment with 6.25 wt% free D609 caused redness in 2 sites, tissue damage in 5 sites, and no effect in 1 site, and was given an irritation score of 12. The ointment with 12.5 wt% free D609 caused reddening in 1 site, inflammation in 1 site, and tissue damage in the remaining 6 sites, and was given an irritation score of 14.5.

The results of this study are graphically represented in FIG 1.

EXAMPLE 4

Assessment of the Irritating Effect of p6Q9/iςςi2-Cpntaining Ointments

P609/KC13 in Free Fo m In order to assess the irritating potential of

D609/KC12-containing ointments, ointments containing equal amounts of D609 and KC12 in free-form were administered to the flanks of eight female, 10 week old, nude mice twice daily. Four animals were treated on each flank with D609/KC12 ointment. The degree of irritation was scored beginning 4 hours after the initiation of treatment according to the following stages: no effect (0), slight redness (0.5), redness (1.0), inflammation (1.5), and visible tissue damage (2.0).

When examined 4 hours after treatment, the ointment containing 1.25 wt% free D609/KC12 caused reddening in 1 out of 8 application sites, and was given an irritation score of 1. The ointment with 2.5 wt% free D609/KC12 caused reddening in 3 sites, and was given an irritation score of 3. The ointment with 5 wt% free D609/KC12 caused redness in two sites and tissue damage in the remaining six sites, and was given an irritation score of 14. D609/KC12 in Free Form

The same protocol was followed except that the D609/KC12 mixture was incorporated in cholesterol. When examined 4 hours after treatment, the ointment with

D609/KC12 in cholesterol was very well tolerated. The concentrations of D609 had to be increased to 12.5 wt% in order to cause slight reddening in two sites. This test was given an irritation score of l. The reddening of the skin caused by the

D609/KC12 in cholesterol was found to be transient and disappeared within 16 hours after termination of the treatment. The tissue damage, in contrast, which was caused by free D609/KC12 (5 wt%) , failed to disappear within this period of time.

The results of this study are graphically represent in FIG 2.

EXAMPLE 5 Assessment of the Irritating Potential of D609-Containing Solutions After Subcutaneous Injection

In order to assess the irritating potential of D609-containing solutions after subcutaneous injection. 0.1 ml of solutions containing varying amounts of free D609, D609/KC12 mixtures and D609/KC12 mixtures in cholesterol were subcutaneously injected into four female mice (strain NMRI Nu/Nu, 8 weeks old) in both flanks. The degree of irritation was scored 16 hours after treatment according to the following stages: no effect (0), slight redness (0.5), redness (1.0), inflammation (1.5), and visible tissue damage (2.0).

The summarized scores of each treatment are indicated in Table 2 and FIG. 3.

EXAMPLE 6

Antiviral and Antitumor Activity of D609 Incorporated in Cholesterol

A. Antiviral Activity of the D605/KC12 Mixtures in Free

Form and in Cholesterol

Monkey kidney cells (Rita) were seeded in Linbro plates (4 x 10⁶ each) . After one day, the cells were infected with 100 pfu of herpes simplex virus type 1 (HSV-l) per well. After about one hour absorption, fresh tissue culture medium (Basal medium Eagle; 10% fetal calf serum, pH 7.4) containing concentrations of either free D609/KC12 (10 mg/ml in acetone) or D609/KC12 incorporated in cholesterol (10 mg/ml in 0.9% NaCl buffer solution) was added (2 wells each) . One day later, the tissue culture medium was omitted, the cells were fixed with 3% formaldehyde and stained with 0.5% cristal violett. Plagues were then counted and the mean values calculated. FIG. 4 shows the comparison of the dose- response curve for free D609/KC12 and D609/KC12 incorporated in cholesterol, respectively. The study demonstrates that there was no loss of antiviral activity by incorporation of the active components in cholesterol. B. Antitumor Activity of D609/KC12 Mixtures in Cholesterol

Human colorectal carcinoma cells (5 millions in 0.1 ml isotonic salt solution) were injected subcutaneously into both flanks of athymic nude mice (NMRI, 8 weeks old). After 10 days, tumors appeared and the mice were treated subcutaneously at the site of the tumors with a 0.2 ml of either a control solution of isotonic salt solution (placebo) or a test solution containing D609/KC12 incorporated in cholesterol having a concentration of lOmg/ml of D609. FIG. 5 and Table 3 show the treatment response to D609/KC12 in cholesterol. The mean values of relative tumor sizes (tumor size at the beginning of treatment = 100%) are given over a two week period. The study demonstrates that the xanthate/adjuvant mixture in cholesterol had excellent antitumor activity.

EXAMPLE 7

Preparation of Compositions Containing D609/KC12 in the Lipjd-Based Carrier Lecithin For Therapeutic Test

Purposes The composition is prepared in a manner similar to that of Example 2 by mixing 2 grams of D609 and 2 grams of KC12 with 4 grams of lecithin. Sterile, pyrogen-free water is added to make up a final volume of 40 ml of suspension. The suspension is placed in an external ice bath and sonified. The results achieved with this composition are similar to the results achieved with the composition of Example 2, with respect to skin irritation levels (Examples 4 and 5) , and with respect to antiviral and antitumor activity (Example 6) .

EXAMPLE 8 Preparation of Compositions Containing D609/KC12 in the Lipjd-Based Carrier Phosphatidylcholine For Therapeutic

Test Purposes The composition is prepared in a manner similar to that of Example 2 by mixing 2 grams of D609 and 2 grams of KC12 with 4 grams of phosphatidylcholine.

Sterile, pyrogen-free water is added to make up a final volume of 40 ml of suspension. The suspension is placed in an external ice bath and sonified. The results achieved with this composition are similar to the results achieved with the composition of Example 2, with respect to skin irritation levels (Examples 4 and 5) , and with respect to antiviral and antitumor activity (Example 6) . EXAMPLE 9

Preparation of compositions containing P6Q9/κci2 j_n the ipid-Pasefl Carrier Phosphatidyiserjne For Therape tic

Test Purposes The composition is prepared in a manner similar to that of Example 2 by mixing 2 grams of D609 and 2 grams of KC12 with 4 grams of phosphatidylserine. Sterile, pyrogen-free water is added to make up a final volume of 40 ml of suspension. The suspension is placed in an external ice bath and sonified. The results achieved with this composition are similar to the results achieved with the composition of Example 2, with respect to skin irritation levels (Examples 4 and 5) , and with respect to antiviral and antitumor activity (Example 6) .

EXAMPLE 10 Preparation of Compositions Containing D609/KC12 in the Lipid-Based Carrier Phosphatidylinsitol For Therapeutic

Test Purposes The composition is prepared in a manner similar to that of Example 2 by mixing 2 grams of D609 and 2 grams of KC12 with 4 grams of phosphatidylinositol.

Sterile, pyrogen-free water is added to make up a final volume of 40 ml of suspension. The suspension is placed in an external ice bath and sonified. The results achieved with this composition are similar to the results achieved with the composition of Example 2, with respect to skin irritation levels (Examples 4 and 5) , and with respect to antiviral and antitumor activity (Example 6) . EXAMPLE 11 Preparation of Compositions Containing D609/KC12 in the Lipid-Based Carrier Ganglioside For Therapeutic Test Purposes

The composition is prepared in a manner similar to that of Example 2 by mixing 2 grams of D609 and 2 grams of KC12 with 4 grams of ganglioside. Sterile, pyrogen-free water is added to make up a final volume of 40 ml of suspension. The suspension is placed in an external ice bath and sonified. The results achieved with this composition are similar to the results achieved with the composition of Example 2, with respect to skin irritation levels (Examples 4 and 5) , and with respect to antiviral and antitumor activity (Example 6) .

EXAMPLE 12

Preparation of Compositions Containing D609/KC12 in the

Lipid-Based Carrier Sphingomvelin For Therapeutic Test

Purposes The composition is prepared in a manner similar to that of Example 2 by mixing 2 grams of D609 and 2 grams of KC12 with 4 grams of sphingomyelin. Sterile, pyrogen-free water is added to make up a final volume of 40 ml of suspension. The suspension is placed in an external ice bath and sonified. The results achieved with this composition are similar to the results achieved with the composition of Example 2, with respect to skin irritation levels (Examples 4 and 5) , and with respect to antiviral and antitumor activity (Example 6) . EXAMPLE 13

Preparation of Compositions Containing D609/KC12 in the Steroid-Based Carrier Stearylaroine For Therapeutic Test

Purposes The composition is prepared in a manner similar to that of Example 2 by mixing 2 grams of D609 and 2 grams of KC12 with 4 grams of stearylamine. Sterile, pyrogen-free water is added to make up a final volume of 40 ml of suspension. The suspension is placed in an external ice bath and sonified. The results achieved with this composition are similar to the results achieved with the composition of Example 2, with respect to skin irritation levels (Examples 4 and 5) , and with respect to antiviral and antitumor activity (Example 6) .

EXAMPLE 14

Preparation pf Compositions containing PSPP/KClZ in the

Steroid-Based Carrier Chondrillasterol For Therapeutic Test Purposes

The composition is prepared in a manner similar to that of Example 2 by mixing 2 grams of D609 and 2 grams of KC12 with 4 grams of chondrillasterol. Sterile, pyrogen-free water is added to make up a final volume of 40 ml of suspension. The suspension is placed in an external ice bath and sonified. The results achieved with this composition are similar to the results achieved with the composition of Example 2, with respect to skin irritation levels (Examples 4 and 5) , and with respect to antiviral and antitumor activity (Example 6) .

EXAMPLE 15

Preparation of Compositions Containing D609/KC12 in the

Steroid-Based Carrier α.ff,γ Sitosterol For Therapeutic

Test Purposes The composition is prepared in a manner similar to that of Example 2 by mixing 2 grams of D609 and 2 grams of KC12 with 4 grams of α,,9,γ sitosterol. Sterile, pyrogen-free water is added to make up a final volume of 40 ml of suspension. The suspension is placed in an external ice bath and sonified. The results achieved with this composition are similar to the results achieved with the composition of Example 2, with respect to skin irritation levels (Examples 4 and 5) , and with respect to antiviral and antitumor activity (Example 6) . EXAMPLE 16 Preparation of Compositions Containing D609/KC12 in the Steroid-Based Carrier Cholestanol For Therapeutic Test

Purposes The composition is prepared in a manner similar to that of Example 2 by mixing 2 grams of D609 and 2 grams of KC12 with 4 grams of cholestanol. Sterile, pyrogen-free water is added to make up a final volume of 40 ml of suspension. The suspension is placed in an external ice bath and sonified. The results achieved with this composition are similar to the results achieved with the composition of Example 2, with respect to skin irritation levels (Examples 4 and 5) , and with respect to antiviral and antitumor activity (Example 6) .

EXAMPLE 17 Preparation of Compositions Containing D609/KC12 in the Steroid-Based Carrier Cholanic Acid For Therapeutic Test

Purposes The composition is prepared in a manner similar to that of Example 2 by mixing 2 grams of D609 and 2 grams of KC12 with 4 grams of cholanic acid. Sterile, pyrogen-free water is added to make up a final volume of 40 ml of suspension. The suspension is placed in an external ice bath and sonified. The results achieved with this composition are similar to the results achieved with the composition of Example 2, with respect to skin irritation levels (Examples 4 and 5) , and with respect to antiviral and antitumor activity (Example 6) .

Claims

WHAT IS CLAIMED IS:

1. A pharmaceutical composition having antiviral or antitumor activity comprising an effective amount of (a) a xanthate compound and (b) an activity enhancing adjuvant, incorporated in a lipid-based or steroid-based carrier.

2. A composition of claim 1 wherein the composition is an antiviral agent.

3. A composition of claim 1 wherein the composition is an antitumor agent.

4. A pharmaceutical composition having antiviral or antitumor activity comprising:

(a) a xanthate compound of the formula (I) :

S (I)

\ ₂ S — R² wherein

R¹ represents norbornyl, tricyclodecyl, benzyl, straight or branched C₃-C₂₀-alkyl, C₃-C₂₀- cycloalkyl, furyl, pyridyl, guinuclidinyl; straight or branched C₃-C₂₀-alkyl substituted by hydroxy,

C -C₄-alkoxy, or halogen; or C₃-C₂₀- cycloalkyl substituted by hydroxy, C₂-C₄-alkoxy, C₂-C₄-alkyl, or halogen; and R² represents a monovalent or ultivalent metal atom, straight or branched C₂-C₆-alkyl, straight or branched C₂-C₆-alkyl substituted by hydroxy, C₂-C₄-alkoxy, a ino, C₂~C₄- alkylamino, (C₂-c₄-alkyl)₂-amino, (C₂-C₄- alkyl)₃-ammonium, or halogen; or 2,3- dihydroxypropyl or ω-hydroxy-(C₂~C₄- alkoxy)-methyl, or a pharmaceutically acceptable salt thereof; (b) an activity enhancing adjuvant comprising a compound having both a lipophilic group and a hydrophilic group, wherein the lipophilic group comprises an aliphatic group with six to eighteen carbon atoms, and the hydrophilic group comprises one or two carboxyl, sulphate, sulphonate, or phosphate groups, or a pharmaceutically-acceptable salt thereof; and

(c) a lipid-based or steroid-based carrier.

5. A composition of claim 4 wherein the xanthate is sodium or potassium benzylxanthate, cyclohexylxanthate,

1-adamantylxanthate, 8(9)-tricyclo[5.2.1.0^2*6]- decylxanthate, 2-endo or exo-bicyclo[2.2.1^1,4]-heptyl- xanthate, cyclododeeylxanthate, n-dodecylxanthate, or 4- isoborny1-cyclohexylxanthate.

6. A composition of claim 4 wherein the adjuvant compound is an ionic compound having both lipophilic and hydrophilic groups, wherein the lipophilic group is a straight or branched aliphatic mono or dicarboxylic acid, or fluorinated derivative thereof, or an aliphatic mono or disulphate, mono or disulphonate, or mono or diphosphate, having 6 to 18 carbon atoms, or such a compound having 1 or 2 ether and/or amide groups, and wherein the hydrophilic group comprises 1 or 2 carboxyl and/or 1 or 2 sulphate, sulphonate, or phosphate groups, or pharmaceutically acceptable salts thereof.

7. A composition of claim 4 wherein the adjuvant compound is the sodium or potassium salt of decanoic acid, undecanoic acid, dodecanoic acid, deoxycholic acid, dodecyl sulfate, or dodecylphosphonic acid.

8. A composition of claim 4 wherein the weight ratio of xanthate to adjuvant is from 0.1 to 10 parts xanthate per one part adjuvant.

9. A composition of claim 4 wherein the weight ratio of xanthate to adjuvant is about 1:1.

10. A composition of claim 4 wherein the weight ratio of xanthate and adjuvant to carrier is one part xanthate and adjuvant to 0.25 to 4 parts carrier.

11. A composition of claim 4 wherein the carrier is cholesterol.

12. A composition of claim 4 wherein the xanthate and adjuvant are emulsified with said cholesterol form a micelle therewith or are encapsulated in a liposome made therefrom.

13. A composition of claim 4 wherein the active xanthate is sodium or potassium-8(9)- tricyclo[5.2.1.0²-⁶]-decylxanthate, the activity increasing adjuvant is the sodium or potassium salt of dodecanoic acid, and the carrier is cholesterol.

14. A method of combating a virus or tumor comprising administering to a site of viral disease or to a tumor, an effective amount of a pharmaceutical composition comprising: (a) a xanthate compound of the formula (I) :

S (i)

II

R¹ — O — C

\ S — R² wherein

R¹ represents norbornyl, tricyclodecyl, benzyl, straight or branched C₃-C₂₀-alkyl, C₃-C₂₀- cycloalkyl, furyl, pyridyl, quinuclidinyl; straight or branched

C₃-C₂₀-alkyl substituted by hydroxy, C₂-C₄-alko y, or halogen; or C₃-c₂₀- cycloalkyl substituted by hydroxy, C₂~C₄-alkoxy, C₂~C₄-alkyl, or halogen; and

R² represents a monovalent or multivalent metal atom, straight or branched C₂-C₆-alkyl, straight or branched C_j-Cg-alkyl substituted by hydroxy, C_j^^-alkoxy, amino, C₂-C₄- alkyiamino, (C2-C₄-alkyl)₂-amino, (C₂~C₄- alkyl)₃-ammonium, or halogen; or 2,3- dihydroxypropyl or ω-hydroxy-(C₂~C₄- alkoxy)-methyl , or a pharmaceutically acceptable salt thereof;

(b) an activity enhancing adjuvant comprising a compound having both a lipophilic group and a hydrophilic group, wherein the lipophilic group comprises an aliphatic group with six to eighteen carbon atoms, and the hydrophilic group comprises one or two carboxyl, sulphate, sulphonate, or phosphate groups, or a pharmaceutically-acceptable salt thereof; and

(c) a lipid-based or steroid-based carrier.

15. A method of claim 14 wherein the pharmaceutical composition comprises at least 2.5 wt% xanthate compound in a topical ointment.

16. A method of claim 14 wherein the pharmaceutical composition comprises at least 10 mg/ml xanthate in a solution for intravenous or subcutaneous injection.

17. A method of claim 14 wherein the xanthate is the sodium or potassium benzylxanthate, eye1ohexy1xanthate, 1-adamantylxanthate, 8(9)-tricyclo[5.2.1.0^2,6]- decylxanthate, 2-endo or exo-bicyclo[2.2.1^1,4]-heptyl- xanthate, cyclododeeylxanthate, n-dodecylxanthate, or 4- isobornyl-eye1ohexylxanthate.

18. A method of claim 14 wherein the adjuvant compound is an ionic compound having both lipophilic and hydrophilic groups, wherein the lipophilic group is a straight or branched aliphatic mono or dicarboxylic acid, or fluorinated derivative thereof, or an aliphatic mono or disulphate, mono or disulphonate, or mono or diphosphate, having 6 to 18 carbon atoms, or such a compound having 1 or 2 ether and/or amide groups, and wherein the hydrophilic group comprises 1 or 2 carboxyl and/or 1 or 2 sulphate, sulphonate, or phosphate groups, or pharmaceutically acceptable salts thereof.

19. A method of claim 14 wherein the adjuvant compound is the sodium or potassium salt of decanoic acid, undecanoic acid, dodecanoic acid, deoxycholic acid, dodecyl sulfate, or dodecylphosphonic acid.

20. A method of claim 14 wherein the weight ratio of xanthate to adjuvant is 0.1 to 10 parts xanthate to one part adjuvant.

21. A method of claim 14 wherein the weight ratio of xanthate to adjuvant is one to one.

22. A method of claim 14 wherein the weight ratio of xanthate/adjuvant mixture to carrier is one part xanthate/adjuvant mixture to 0.25 to 4 parts carrier.

23. A method of claim 14 wherein the steroid is cholesterol.

24. A method of claim 14 wherein the xanthate and adjuvant are emulsified within said cholesterol or are encapsulated in a liposome made therefrom.

25. A method of claim 14 wherein the active xanthate is sodium or potassium-8(9)-tricyclo[5.2.1.0²*⁶]- dec lxanthate, the activity increasing adjuvant is the sodium or potassium salt of dodecanoic acid and the carrier is cholesterol.