DE4003783A1 - New phospholipid gel preserved by alcohol(s) - prepd. from natural phospholipid(s) obtd. from oil seeds, used for easy prepn. of liposomal solns. - Google Patents

Abstract

Phospholipid-contg. gel (I) preserved by alcohols, is new. The gel is prepd. from natural phospholipids, obtd. from oil seeds, including phosphatidyl choline (PC), acid phospholipids (AP) and other phospholipids (OP). USE/ADVANTAGE - Gels are useful in many areas, including the food industry, pharmaceutical and cosmetic industries, photography and analytical methods including chromatography. (I) may be used to prepare liposomal solns. (I) are prepd. via a technically easy process. Prepn. of liposomes or liposomal solns. of (I) does not require elevated temps. or ultrasound.

Description

The invention relates to a gel containing phospholipid and a Process for its preparation and its use for the production of liposomal solutions.

Gels are materials or compositions found in many technological fields find wide application, such as e.g. B. in the food industry, cosmetics and Pharmacy, photography or analytical methods like the chromatographic separation process.

Gels are generally considered to be highly viscous or infinite viscous mass considered in which a chain-linked macromolecular system.

However, the actual gel structure itself is very often not clarified, even if a more or less viscous Mass is viewed or labeled as a gel.

The most well known and widespread gels are the aqueous gels, in which water is always present Main component is used. Then it becomes one Added compound that causes gelling and that The strength of the solidification is affected. As the preferred material gelatin is used to produce a gel.

Also known are the so-called organogels, in which the main liquid component is an organic solvent and an added apolar polymer the gelation causes and affects their strength.

PCT / WO 86/02 264 describes a system reverse micelles by adding suitable Solvents such as B. squalene, miglyol or vegetable oils can be converted into appropriate gels. A pharmaceutical use is not possible.

Naturally only come for a pharmaceutical application consider such gels that are made up exclusively of there are pharmaceutically acceptable substances. Here Then the problem arises that many in pharmacy usable and required substances not able are to form gels or gel-like aggregate states.  

Systems in which gels have been studied most have been investigated so far from lecithin or general phospholipids, one Solvent, water and other auxiliary materials required be formed. However, such gels often only serve as Intermediate stage to ultimately create a liposome gel obtained or the desired end product are the liposomes self.

For example, EP-A 01 60 266 describes a liposome Composition claimed from one three dimensional network of liposomes and one Network material exists. For the network material preferably used polysaccharides in which the liposomes are embedded.

According to PCT / WO 85/03 640 loaded liposomes are in one Gel matrix of starch or modified starch claimed.

EP-A 00 69 307 describes a method of representation described a liposome gel, after which an aqueous and Solvent-based lecithin solution with ultrasound is treated. Depending on the duration of the sound and -Intensity forms a more or less viscous gel out. By extending the sonication time or by means of mechanical stirring effect is obtained as the end product Aqueous solution containing liposomes.

A so-called pre-liposome gel is obtained from one Mixture of phospholipids, fatty acids and one hydrating agent (EP-A 02 11 647). After adding Water or buffer solution form liposomes.

A thin gel containing phospholipid is used in the PCT / WO 89/00 077 for use as aerosol liposomes claimed. The system consists of lecithin, one  organic solvents and a little water. Here comes one wide range of liposome diameters in the range of 100 up to 2500 nm; for a meaningful application area a high proportion of solvent can be selected.

Surprisingly, it has now been found that it is possible a gel from the phospholipid-alcohol-water system obtained by using only a small amount of solvent, alcohol. The water forms in the gel clearly the main component.

It is also surprising that the gel is pyrogen-free and germ-free is, and that it is extremely simple in low-germ, pyrogen-free liposomal solutions can be transferred.

Pharmaceutically acceptable and physiologically acceptable alcohols, such as ethanol and 2-propanol used.

The gel is easy to produce Process characterized in which a phospholipid mixture certain composition with a certain amount of Alcohol is stirred briefly and by adding water and further stirring the gel formation takes place.

The method is further characterized in that it in any commercially available laboratory stirrer in any suitable vessel can be carried out. Basic requirement is only a sufficiently high speed, so that in strong mixing is achieved in a short time.

In the preferred embodiment, two different phospholipid mixtures used, the Quantity ratios are in the following areas:

Phospholipid mixture A:

80% phosphatidylcholine
1-19% acidic phospholipids
19-1% other phospholipids

Phospholipid mixture B:

60% phosphatidylcholine
10-30% acid phospholipids
10-30% other phospholipids

Natural ones have proven to be particularly suitable Phospholipid mixtures, such as those found in oilseeds can be won. These preferably include Soybean, rapeseed, sunflower oil and others.

The natural ones extracted from the oilseeds Phospholipid mixtures can, for example, according to EP-S 00 69 770 be worked up, taking the ones mentioned above Phospholipid mixtures A and / or B receives. In these Mixtures belong to the "other phospholipids" Lyso-phosphatidylcholine and phosphatidylinositol while according to the invention, the phosphatidic acid, phosphatidyl ethanolamine and N-acyl-phosphatidylethanolamine to the so-called acidic phospholipids.

Try other ones than those listed above Mixing ratios of A or B or with pure Incidentally, phosphatidylcholine did not lead to the products according to the invention.

A particular advantage of the invention is that too see that for a possibly desired subsequently Production of liposomes or liposomal solution none additional energy consuming steps like Increasing the temperature, ultrasound or the like is necessary are.

The gel formulation according to the invention can contain from 5 to 40 parts by weight of phospholipids will. However, those with 20-30 are preferred Parts by weight of phospholipid produced.  

The gels produced according to the invention have one Alcohol content of 15 to 20, typically 16 weight percent, so that the water content is 44 to 69% by weight, depending on the amount of phospholipid in the end formulation. Of course, instead of water also buffer solutions, such as phosphate buffers or physiological saline can be used.

The invention is illustrated by the examples below explained, the mixtures I as phospholipid mixtures or II can be used with the following composition (Figures in percent by weight).

example 1

10 g of the mixture I are in 8 g of ethanol with stirring dissolved. The solution has a viscosity of 806 mPas (at 25 ° C) and is homogeneous. The solution comes with 32 g demineralized water homogenized for 3 minutes, being a commercially available high-speed laboratory stirrer is used. A transparent gel is obtained with 20% by weight phospholipid content.  

Example 2

Analogously to Example 1, 15 g of mixture I are dissolved in 8 g of ethanol. The solution is stirred with 27 g of demineralized water for 3 minutes until a homogeneous, transparent gel is formed. The gel contains 30% by weight of phospholipids.

Example 3

Analogously to Example 1, 10 g of the mixture II in 8 g Ethanol dissolved. After adding 32 g demineralized Water is stirred for a further 3 minutes. It arises transparent gel with 20% by weight phospholipid content.

Example 4

Analogously to Example 1, 20 g of the mixture I in 8 g of 2- Dissolved propanol. There are 27 g of demineralized water added and stirred for three more minutes. It arises transparent gel with 27.5% by weight phospholipid content.

Example 5

As in Example 1, 10 g of mixture I become 8 g 2-propanol dissolved. After adding 37 g mineralized water is stirred for 3 minutes and one receives a transparent gel with 18.2% by weight phospholipid salary.

Example 6

Analogously to Example 1, 15 g of mixture II - instead of Mixture I - dissolved in 8 g of 2-propanol. After adding 27 g demineralized water and a stirring time of 3 minutes you get a transparent gel with 30% by weight Phospholipid content.

The following examples show how simple Process steps from the gel containing phospholipid Preserve low-germ and conserved liposomal solutions can be. The bacterial count is in all end products below 100 germs / g and thus corresponds to the USP21 and DAB9 standards.  

Example 7

The total amount of the phospholipid gel obtained in Example 1 (50 g) is mixed with 42 g of 0.2 molar NaKHPO ₄ buffer solution and stirred for 4 minutes. The resulting low-viscosity dispersion is mixed with 8 g of ethanol and stirred for a further 1 minute until the finished end product. The ratios of phospholipids: ethanol: water are 10: 16: 74. The particle size, measured by the laser scattered light method, is 204 nm (± 20%); the bacterial count is below 100 germs / g.

Example 8

The total amount of that obtained in Example 2 Phospholipid gels (50 g) are mixed with 84 g tap water added, stirred for 4 minutes and then 16 g of ethanol admitted. After a further stirring time of 1 minute the end product is a liposomal solution with 16% Phospholipid content and an average particle size of 194 nm (± 20%). Despite using tap water, usually with microorganisms and salts is contaminated, the product contains less than 100 germs / g.

Example 9

50 g of the phospholipid gel obtained according to Example 3 are mixed with 42 g of salt solution, stirred for 4 minutes, 8 g of ethanol were added and stirring was continued for 1 minute. The Ready-to-use vesicles liposomal solution have an average diameter of 154 nm (± 20%).

Example 10

Analogous to Example 8, the total amount of gel Example 4 111 g of physiological saline solution were added. After 4 minutes of stirring, 24 g of 2-propanol are added and stir for 1 more minute. The average particle size of the Vesicle in the liposomal solution is 122 nm (± 20%).  

Example 11

The phospholipid gel obtained in Example 5 is under 37 g of buffer solution (phosphate buffer) are added, 4 Stirred minutes, 8 g of 2-propanol were added and another 1 minute continued stirring. The average particle size of the vesicles in the liposomal solution is 187 nm (± 20%).

Example 12

The total amount of gel from example 6 is used. This is mixed with 111 g of phosphate buffer solution, Stirred for 4 minutes, 16 g of 2-propanol were added and 1 minute continued stirring. The mean size of the vesicles in the so obtained liposomal solution is 162 nm (± 20%).

As in Examples 9-15, the bacterial count is also here below 100 germs / g.

Summary

The invention relates to a gel containing phospholipid and a Process for its preparation and its use for the production of liposomal solutions.

Claims (10)

1. Phospholipid-containing gel, characterized in that it is preserved with alcohols. 2. Phospholipid gel according to claim 1, characterized characterized in that the starting material is natural Phospholipids derived from oilseeds be used. 3. Phospholipid-containing gel according to claim 1 and 2, characterized in that a phospholipid mixture of the composition 80 wt .-% phosphatidylcholine as the starting material
1-19% by weight acidic phospholipids
19-1% by weight of other phospholipids is used. 4. Phospholipid-containing gel according to claim 1 or 2, characterized in that a phospholipid mixture of the composition 60 wt.% Phosphatidylcholine as the starting material
10-30% by weight acidic phospholipids,
10-30% by weight of other phospholipids is used. 5. Phospholipid gel according to claims 1, 2, 3 or 4, characterized in that the alcohol is 2-propanol or is ethanol. 6. phospholipid-containing gel according to claims 1 to 5, characterized in that the alcohol content in the Gel formulation 15% to 20% by weight, typically 16% by weight. 7. phospholipid-containing gel according to claims 1-6, characterized in that the phospholipid content in Gel maximum 40% by weight, usually 20 to 30% by weight is. 8. phospholipid-containing gel according to claims 1 to 7, characterized in that the phospholipid Starting material a liquid phospholipid alcohol Mixture is. 9. Process for the preparation of a phospholipid Gels according to claims 1 to 8, characterized characterized in that a phospholipid-alcohol mixture according to the above claims with so much water stirs that a gel is formed. 10. Use of the phospholipid-containing gel of claims 1-8 for the preparation of liposomal solutions.