CA2079868A1

CA2079868A1 - Pharmaceutical for treating viral diseases

Info

Publication number: CA2079868A1
Application number: CA002079868A
Authority: CA
Inventors: Joachim Roding; Ursula Meusel
Original assignee: Individual
Current assignee: A Natterman und Cie GmbH
Priority date: 1991-02-07
Filing date: 1992-02-03
Publication date: 1992-08-08
Also published as: DE4121389A1; JPH05506671A; IE920400A1; EP0527979A1; WO1992013524A1

Abstract

Abstract A pharmaceutical product is described for the treatment of virus diseases, particularly of virus diseases of the skin, whereby the pharmaceutical product is characterized by at least one virucidal active ingredient, that is encapsulated in a multilamellar liposome system.

Description

21~7.98G,8 Pharmaceutical product for the treatment of virus d~seases The present inventlon relatès to a pharmaceutical product for the treatment of viru~ ea~es ~ith the characteri~tic~
of the general descrlption ~n claim 1.

In order to treat vlrus disea~es, particularly virus-depen-dent skin diseases, ~uch à9, for example, herpes simplex, herpes labialis, herpe~ genltalis, herpe~ anali~, herpe~
gestationis, herpes faciali~, herpes febrilis, herpes men-struali~ or herpes zoster, it is cu~tomary to apply an ointment-like or cream-likè product to the areas of ~kin affected by the disease. So, for example, a cream fre~uently employed for the therapeutic treatment of the aforementioned diseases contalns 50 mg acyclovir as active in~redient together wlth conventional ~dditives such a~, for example, propylene glycol, poloxame~ ind cetyl~tearyl alcohol.

2 ~ S ~

However, the known creams and ointments suffer from the disadvantage that they must be applied regularly and at short intervals, for example every 2 to 4 hours, since healing or relief cannot otherwise be guaranteed. However, this treatment is not always carried out conscientiously by all patients, so that the desired success frequently does not occur. Furthermore, treatment with the known pharmaceut-ical products is limited to a few days, for example to 5 or a maximum of 10 days.
The purpose of the present invention is to make available a pharmaceutical product of the aforementioned type that can be npplied safely and without side effects over a longer period of time.
According to the invention this purpose is fulfilled by a pharmaceutical product with the characteristic attributes of claim 1.

Thus, according to the invention, a pharmaceutical product is proposed for the topical treatment of virus diseases, particularly of virus diseases of the skin, with at least one virucidal active ingredient encapsulated in a multi-lamellar liposome system.
Whereby in the present application the term liposomes is understood to refer to spheres (vesicles) that are bounded by lipid double membranes and contain within them an aqueous phase in which at least one virucidal active ingredient is dissolved, dispersed or emulsified.

The pharmaceutical product according to the invention exhi-bits a number of advantages over the known ointment-like or cream-like preparations. Firstly, it has become apparent that, in contrast to the known agents, the preparation - 2~79~,~8 according to the invention has to be applied to the diseased areas appreciably less frequently over a period of time, for example one day. This is attributed to the pharmaceutical product accordinq to the invention possessing a depot effect since the active ingredient is encapsulated in the liposomes and i5 slowly and evenly released from these. Furthermore, the therapeutic product according to the invention possesses a better bioavailability, since the liposomes are stored in the skin and particularly in the stratum corneum, so that it is not necessary to cross the barrier of the horny layer.
This again leads to the deeper skin layers in the dermis being reached so that the viruses to be found in these deeper skin layers are killed. Furthermore, the pharma-ceutical preparation according to the invention possesses a high storage stability, since as stated previously, the minimum of one active ingredient is encapsulated in the liposomes and, hence, is optimally protected against exter-nal influences, for example oxidation.

At least one polyanion, preferably dextran sulphate and/or a derivative thereof as virucidal agent has been found to be a particularly suitable method of realizing the pharmaceutical product according to the invention. Hereby this is preferab-ly a sulfuric acid ester of dextran, whereby dextran is a glucose polymer.

Particularly dextran sulphate is employed in the form of a salt, preferably its sodium or potassium salt.

The derivatives of dextran sulphate that come into question are particularly the esters, preferably the methyl, ethyl, propyl, butyl esters, whereby esterification can involve both the SO~OH groups and the hydroxy groups.

2~7!~fi~

The molecular weight of the polyanion, particularly of the dextran sulphate, of the corresponding salt and/or deriva-tive lies preferably between 5000 and 15000, particularly between 7000 and 12000.

The concentration of the virucidal active ingredient or of the mixture of virucidal active ingredientq in the pharma-ceutical product according to the invention is adjusted according to the nature of the virucidal compounds employed, the regions of the body to be treated and the severity of the disease. In general the concentration of virucidal active ingredient in the product according to the invention ranges from 0.001% by weight to 5~ by weight of the mass of the liposome system in which the active ingredient is encap-sulated. In the case of mild disorders and for applicationto the mucosa application forms of the product according to the invention are employed whose active ingredient concen-tration lies between 0.001% by weight and 0.1% by weight. In the case of severe disorders and particularly of those disorders where the virus infection does not extend to the mucous membranes, products are preferably used whose active ingredient concentration lies between 0.1% by weight and 2%
by weight. However, if it is desired to exploit the depot effect brought about by encapsulation of the active ingre-dient or active ingredient mixture in the liposome systemthe active ingredient concentration in the product according to the invention can be raised to 2% by weight to 5% by weight, whereby such a product must be applied at correspon-dingly extended intervals, particularly in a 24 hour rhythm.
The aforementioned concentration ranges are in each case with respect to the mass of the liposome system that encap-sulates the active ingredient or the active ingredient mixture.

207.~8 In order to improve the deposition of the product in the skin and particularly in the stratum corneum, in the case of the product according to the invention such liposome systems are preferably chosen whose liposomes have a mean diameter between 100 nm and 500 nm. Here liposome systems with a mean liposome diameter of about 150 nm to about 300 nm have shown themselves to be particularly advantageous.

It has also been established to be advantageous, that such liposome systems that exhibit a negative surface charge penetrate the skin particularly rapidly and well and, hence, possess high effectivîty.

With respect to the liposome system encapsulating the active ingredient or mixture of active ingredients in the pharma-ceutical product according to the invention, it may be stated in general that any suitable liposome system may be used that fulfils the aforementioned conditions concerning mean diameter and surface charge and forms multilamellar vesicles. However, the product according to the invention is preferably used in which the liposomes are present in the form of a gel-like dispersion, that contains 8 to 22% by weight soya phospholipids together with water and/or alcohol in addition to the active ingredient or active ingredient mixture.

A particularly high efficacy, expressed in the form of a good depot effect, and a particularly good bioavailability of the active ingredient or of the active ingredient mixture are exhibited by forms of realization of the pharmaceutical product according to the invention where the soya phospholi-pids contain a high concentration of phosphatidylcholine, particularly from 60% by weight to 98% by weight phosphati-dylcholine and 2% by weight to 40% by weight of other phos-pholipids, such as, in particular, phosphatidylethanolamine, 2 ~ 8 phosphatidic acid and/or phosphatidylinositol.

A further improvement in efficacy, particularly with respect to herpes simplex, is achieved for the product according to the invention where a liposome system is used which i9 made up of specific soya phospholipids, whereby these specific soya phospholipids contain 76 + 3% by weight phosphatidyl-choline and 0 to 6% by weight lysophosphatidylcholine. More-over, these soya phospholipids can also contain the afore-mentioned other phospholipids particularly ca. 5% by weightphosphatidylethanolamine, ca. 8% by weight phosphatidic acid and/or traces of phosphatidylinositol. In particular such a liposome system is excellently suitable for the encapsula-tion of active ingredients based on polyanions, particularly based on dextran sulphate, derivatives andJor salts of dex-tran sulphate, and for the release of these evenly over an appropriately extended period of time after penetration of the liposomes into the skin, so that such a mode of execu-tion of the product according to the invention possesses an excellent depot effect and, hence, an excellent long-term effect.

A form of realization of the product according to the inven-tion characterized by high purity soya phospholipids con-taining 93 + 3% by weight phosphatidylcholine and 0-6% by weight lysophosphatidylcholine was found to be particularly suitable for the complete avoidance of undesired but harm-less side effects, such as, for example, the occurrence of skin reddening in especially sensitive patients, and for further improvement of the aforementioned advantages. These soya phospholipids do not contain or contain only traces of the aforementioned other phospholipids, whose detection limit is ca. 0.5% by weight.

In order to ensure that the product according to the ~ S~ T

2~7~98fi8 invention has a long storage life and in particular to ensure good liposome stability, the product according to the invention contains, in addition to the liposome system and the active ingredient, between ca. 12% by weight and ca. 20%
by weight, preferably ca. 16% by weight alcohol, particular-ly ethanol and/or 2-propanol, as well as between ca. 80% by weight and about 58% by weight water. In this context it has been established that, in addition to exhibiting excellent storage properties over several years, such a product is also topically applicable with outstanding effectivity and without the occurrence of skin irritation.

The present invention also refers to a method for the prepa-ration of the pharmaceutical product described above, that contains soya phospholipids of the aforementioned type as the liposome system.

According to the invention such a product is prepared by dissolving a phospholipid mixture in alcohol, preferably ethanol and/or 2-propanol, and thereafter adding sufficient water to produce a gel and then mixing the gel, for example by stirring, with at least one active ingredient.

Unexpectedly it could be established that the aforementioned method resulted in the formation of liposomes, that encapsu-late the aforementioned added active ingredient, whereby these liposomes display a defined and constant particle size between ca. 150 nm and ca. 300 nm, preferably ca. 230 nm.
Furthermore, it could also be established that, as a result of the addition of water and/or further dilution with water, free liposomes with several bilayers were formed in the pharmaceutical product. Furthermore, in the method according to the invention it is not necessary to carry out addition-al, energy-consuming steps involving, for example, the rais-ing of the temperature, the application of ultrasound or SHEE~

2~7~

excessive stirring in order to prepare the liposomes that encapsulate the active ingredient or mixture of active in-gredients. It i9 sufficient here if the above-mentioned components are stirred together for 2 to 8 minutes with a laboratory stirrer of conventional construction. Further-more, it was also possible to establish that the product according to the invention has an extremely low microbiolo-gical count of less than 100 organisms/g, thus fulfilling the USP 21 and DAB 9 standard~.
A further mode of execution of the method according to the invention proposes that the phospholipid mixture be dissol-ved in only a part of the required quantity of alcohol and that the remaining part of the alcohol be added during and/or after stirring the gel with the active ingredient and then the necessary amount of water be added in order to adjust the viscosity to that desired for the pharmaceutical product. Here it has been found to be particularly suitable when the phospholipid mixture is first dissolved in 10% by weight to 30% by weight of the required amount of alcohol and then the remaining alcohol, i.e. 70% by weight to 90% by weight, is added during and/or after stirring the gel with the active ingredient.

Advantageous developments of the pharmaceutical product according to the invention are mentioned in later claims.

The pharmaceutical product according to the invention will be further explained with the aid of two execution examples.
Example 1 20 g of a phospholipid mixture comprising 82.5 + 3.5% by weight phosphatidylcholine (3-Sn-PC), not more than 10% by weight phosphatidylethanolamine 5~3~ ~~ S~ T

2079~6~

0 - 6% by weight lysophosphatidylcholine and not more than 10~ by weight other lipids with a peroxide value of not more than 5 and a total micro-biological count of not more than 100 or~anisms/~ was dissolved in 3.6 g ethanol. Then 47 g demineralized water was added to this solution and the solution waR homogenized for 3 minutes with a rapidly operating laboratory stirrer. A
transparent gel was produced thereby. This gel was stirred with 12.4 g ethanol and differing quantities of dextran sulphate (Table 1), that took the form of a sodium salt and had a molecular weight of ca. 8000 (rapidly operating labor-atory stirrer, 2 minutes). Then the batch was made up to 100 g finished product by the addition of demineralized water followed by a final stirring with a rapidly operating labor-atory stirrer for 2 minutes.

The products so produced were designated products 1-4.

In addition a product range 5-8 was also prepared in parall-el, whereby the same starting materials were used in identi-cal amounts as for products 1-4. However, this time the corresponding amounts of dextran sulphate were not added until the last water had been added and the dextran sulphate and the liposome system were mixed manually in a convention-al mortar.

A product 9 was also prepared in parallel, whereby product 9contained the same components as products 1-8 except that dextran sulphate was omitted from product 9.

2~7~6~

Table 1 Product Concentration of dextran sulphate in 100 g completed product Example 1 Example 2 1 or 1' 1.6 g 2 or 2' 0.16 g 3 or 3' 0.016 g 4 or 4' 0.0016 g or 5' 1.6 g 6 or 6' 0.16 g 7 or 7' 0.016 g 8 or 8' 0.0016 g 9 or 9' 0 g The afore mentioned products 1 to 9 were te~ted on a group of 30 randomly chosen patients all suffering from herpes sim-plex. For this purpose products 1 to 9 were applied locallyto the diseased areas of skin and briefly rubbed in twice daily at 12 hourly intervals.

only three days after the beginning of the treatment there was an appreciable improvement in the disease in patients treated with products 1 to 8. After 6 days of application of products 1, 2, 5 and 6 50S of the patients treated no longer exhibited herpes simplex.

After 6 days of treatment with products 3, 4, 7 and 8 40% of the patients treated no longer exhibited herpes si~plex.

After a further 4 days of treatment the remaining 50% of the patients treated with products 1, 2, 5 and 6 no longer exhibited herpes simplex, while the patients treated with ~ S~E~

~ ~ r~ 8 products 3, 4, 7 and 8 required a total treatment period of 14 days before the herpes simplex disappeared completely.

All patients treated with product 9 exhibited unchanged herpes simplex even after treatment for a period of 14 days.

Example 2 20 g of a phospholipid mixture (soya phospholipid), comprising 95% by weight phosphatidylcholine, 3% by weight lysophosphatidylcholine and 2% by weight other not identified phospholipids was dissolved in 3.6 g ethanol. Then g7 g demineralized water was added to this solution and the solution was homo-genized for three minutes with a rapidly operating labora-tory stirrer. A transparent gel was produced thereby. This gel was stirred with 12.4 g ethanol and the aforementioned differing quantities of dextran sulphate (Table 1), that took the form of a sodium salt and had a molecular weight of ca. 8000 trapidly operating laboratory stirrer, 2 minutes).
Then the batch was made up to 100 g finished product by the addition of demineralized water followed by a final stirring with a rapidly operating laboratory stirrer for 2 minutes.
The products so prepared were designated products 1' - 4'.

Products 5' - 8' were also prepared in parallel, whereby the same starting materials were used in identical amounts as for products 1'-~'. However, this time the corresponding quantities of dextran sulphate were not added until the last water had been added and the dextran sulphate and the lipo-some system were mixed manually in a conventional mortar.

5~ ET

A further product 9' was also prepared in parallel, whereby product 9 contained the same components as products 1' - 8' except that dextran sulphate was omitted from product 9'.

rO The aforementioned products 1' to 9' were tested on a group of 30 chosen patients all suffering from herpes simplex who all complained of skin irritation after the application of other preparations. For this purpose products 1' to 9' were applied locally to the diseased areas of skin and to the neighbouring healthy areas of skin and briefly rubbed in twice daily at 12 hourly intervals.

With respect to the treatment of herpes simplex the results were basically the same as those obtained in example 1, whereby the impression was obtained that the total treatment times tended to be shortened by about 1 to 2 days. However, it was worthy of note that none of the patients suffered skin irritation.

This treatment investigation was naturally also confirmed by the fact that all the patients treated with product 3' exhibited unchanged herpes simplex even after treatment for a period of 14 days.

~?~ ~F~T

Claims

Patent claims

1. Pharmaceutical product for the treatment of virus diseases, particularly virus diseases of the skin, with at least one virucidal active ingredient, wherein the active ingredient is encapsulated in a multilamellar liposome system.

2. Product according to claim 1, wherein it contains at least one polyanion, preferably dextran sulphate, a salt and/or a derivative thereof as virucidal active ingredient.

3. Product according to claim a, wherein the virucidal polyanion has a molecular weight of between 5000 and 15000, preferably between 7000 and 12000.

4. Product according to one of claims 1 to 3, wherein the virucidal active ingredient is present to a concentration of between 0.001% by weight and 5% by weight with respect to the mass of the liposome system.

SUBSTITUTE SHEET

5. Product according to one of the aforementioned claims, wherein it contains a liposome system, containing liposomes with a mean diameter of between 100 nm and 500 nm.

6. Product according to claim 5, wherein the liposomes of the liposome system possess a mean diameter of between about 150 nm and 300 nm.

7. Product according to one of the aforementioned claims, wherein it contains a liposome system that possesses a negative surface charge.

8. Product according to one of the aforementioned claims, wherein the liposome system is a gel-like liposome disper-sion, that, in addition to at least one active ingredient, contains 8 to 22% by weight soya phospholipids together with water and/or alcohol.

9. Product according to claim 8, wherein the soya phospho-lipids contain 60 to 98% by weight phosphatidylcholine and 2 to 40% by weight other phospholipids.

10. Product according to claim 8 or 9, wherein the soya phospholipids contain 76 ? 3% by weight phosphatidylcholine and 0 to 6% by weight lysophosphatidylcholine.
SUBSTITUTE SHEET

11. Product according to claim 8 or 9, wherein the soya phospholipids contain 93 ? 3% by weight phosphatidylcholine and 0 to 6% by weight lysophosphatidylcholine.

12. Product according to one of claims 5 to 11, wherein the liposome system contains between 12% by weight and 20% by weight alcohol, in particular ethanol and/or 2-propanol, and between 80% by weight and 58% by weight water in addition to the phospholipids.

13. Method of preparation of the pharmaceutical product according to one of claims 8 to 12, wherein the soya phos-pholipids are dissolved in alcohol, preferably ethanol or 2-propanol, then sufficient water is added to produce a gel and the gel is mixed with at least one active ingredient.

14. Method according to claim 13, wherein the soya phospho-lipids are dissolved in only a portion of the quantity of alcohol and the remainder of the alcohol and water is added during and/or after mixing the gel with the active ingre-dient.

15. Method according to claim 14, wherein the first portion of the alcohol amounts to between 10 and 30% by weight and the remaining portion lies between 70 and 90% by weight.
SUBSTITUTE SHEET