SE518823C2 - Oil-in-water emulsions - Google Patents

Abstract

The invention relates to an oil-in-water emulsion comprising 0.01-50 percent by weight of the total preparation, preferably 0.1-10 percent, of a galactolipid material as an emulsifier. The galactolipid material consists of at least 50 percent digalactosyldiacylglycerols, the remainder being other polar lipids. The said emulsion is suitable as a carrier for one or more active substances in a pharmaceutical composition, but also in nutritional, cosmetical, food and agricultural products.

Description

n. n. 1. f. f. "n an g. '' 0 c n 518 823 - ~ -m :: m 11 w-- n; ø z:" z: °: e - - - - s fl ~. ». n. I. 1 :. ',' 2 smiles industrial safety and handling aspects.

Prior Art EP-A2-0 402 090 describes an edible oil-in-water emulsion suitable for creams and dressings comprising 10-99% of the entire oil and fat content of a diglyceride mixture. To improve stability, the emulsion may also contain 0.1-10%, based on the oil phase, phospholipids.

EP-A2-0 391 369 discloses a stable pharmaceutical composition of an oil-in-water type emulsion comprising an effective amount of a lipophilic drug. The emulsion is composed of 3-50% of an oily carrier, mainly MCT oil, 0.05-20% of a phospholipid, 0.03-10% of a nonionic surfactant, and 0.05- -50% of a ionic surfactant. The improved stability is said to be caused by a synergism between the indicated constituents.

Glycosylglycerides are a type of glycolipids that are well known constituents of cell membranes in plants. Two types based on galactose are very common, monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) which make up up to 40% of the dry weight of the thylakoid membranes. The monoacyl compounds may also be present to some extent, i.e. monogalactosyl monoacylglycerol (MGMG) and digalactosyl monoacylglycerol (DGMG). To some extent, a sulfolipid consisting of MGDG containing -SO 3 H and known as sulfokinovosyldiacylglycerol may also be present.

SE 9400368-8 describes an industrially useful process for the preparation of glycosylglycerides from plants, preferably cereals, by means of extraction and chromatographic separations.

There is no knowledge or description in the art of any preparation or formulation of the type described below based on glycosylglycerides.

Disclosure of the Invention The present invention relates to an oil-in-water emulsion comprising 0.01-50% by weight of the whole composition, preferably 0.1-10%, of an emulsifier and 0.1-70% by weight of the whole the preparation of an oily material emulsified in an aqueous solution, characterized in that the emulsifier is a glycosylglyceride having the general formula 518 823; :: = ¿:: _; fi f fi g. .

R 1 -o-cnz R 2 -o-cH Hzc-o I (monosaccharide cnzo) n-Ra wherein R 1 and R 2 are independently saturated or unsaturated, linear or branched fatty acid residues having 0-24 carbon atoms and 0-6 double bonds; monosaccharide independently represents a pentose or a hexose; n is 1-5; and R 3 is hydrogen or -SO 2 H; or a mixture thereof, optionally with phospholipids or other emulsifiers.

The oily material is any lipophilic material that has a liquid or semi-solid consistency at room temperature. There are no special restrictions on the oily material. Vegetable oils, animal oils, synthetic oils, fatty acids, natural synthetic glycerides and lipophilic drugs, etc. can be mentioned as examples.

The ratio of emulsifier to oily material is in the range 1: 40-1: 10 by weight, preferably 1: 25-1: 15 by weight.

The glycosylglyceride emulsifier is suitably a mixture of glycosylglycerides of the general formula R1-o-c cz Rz-o-cn Hzc-o II galactose CH20-R3 wherein R1 and R2 are independently saturated or unsaturated fatty acid residues with 10-22 carbon atoms, suitably 16 18, and 0-3 double bonds, and R 3 is hydrogen or a galactose group.

Preferred examples of fatty acid residues R1 and R2 are naturally occurring fatty acyl groups, such as from the saturated acids palmitic acid (C15H31CO; 16: 0) and stearic acid (C17H35CO; 18: 0) from the monounsaturated acid oleic acid (C17H33CO; 18: 1) and from the polyunsaturated acids linoleic acid (C 17 H 31 CO; 18: 2) and. | a. .. 518 823 H nu .n J »J. Ü .. linolenic acid (C17H29CO; 18: 3).

Preferred examples of monosaccharides are the pentoses ribose, arabinose, xylose and ribulose; the hexoses glucose, mannose, galactose, fructose and sorbos.

An advantageous inherent property of the glycosylglycerides is the carbohydrate moieties which comprise the polar head group in each lipid molecule, which can sterically stabilize the emulsion droplets and thereby give an extended life after injection into the blood.

The specific amounts of the components of the glycosylglyceride material used as an emulsifier are not critical to the present invention. However, maximum benefits are achieved through a high content of digalactosyldiacylglycerols (DGDG), the most important bilayer component, in every conceivable application.

A preferred glycosylglyceride material therefore consists mainly of DGDG but also of monogalactosyldiacylglycerols (MGDG). Synthetic glycosylglycerides based on galactose or any other carbohydrate moiety, such as glucose, and natural glycosylglycerides, isolated from any source, based on non-galactose carbohydrate moieties, such as glucose, may be used in accordance with the invention.

The glycosylglyceride material can be extracted from almost any type of glycolipid-containing plant material. Preferred plant materials are seeds and grains from cereals and cereals, e.g. wheat, rye, oats, corn, rice, millet and sesame. Oatmeal as well as wheat gluten have a high lipid concentration and are therefore suitable for use in the production process.

The oil-in-water emulsions of the invention are prepared using glycosylglycerides as emulsifiers but may contain other low molecular weight compounds in an effective isotonic amount. The oil-in-water emulsion may optionally also include other additives known in the art to enhance various aspects of the composition, such as flavors, colorants, preservatives, antioxidants, etc.

The emulsions are prepared by conventional methods. For example, a 30% (w / w) emulsion of medium chain triacylglycerol oil (MCT oil) is prepared in water by dispersing the emulsifier, i.e. the glycosylglyceride material, in the oil.

Glycerol and water are mixed. The oil phase as well as the aqueous phase are 518 szs: Ißgiig 555; _ .a- «u ø a | | . . . Is heated and then the oil phase is added to the aqueous phase while mixing with vigorous shaking. The pre-emulsion is adjusted to pH 7-8.5 during this mixture with vigorous shaking. It is then subjected to homogenization under high pressure.

The invention also relates to a pharmaceutical composition comprising a bioactive material in combination with the oil-in-water emulsion.

The bioactive substance can be a lipophilic drug such as anticancer drugs, antimicrobial and especially antifungal drugs, immunosuppressive drugs such as cyclosporine, dermatological drugs, psychotropic drugs, anesthetic drugs and other lipophilic drugs that have formulation solutions. by the use of glycosylglycerides. A preferred oily material for the emulsion is an MCT oil. There are also many lipids such as fatty acids, mono-, di- and triacylglycerols, phospholipids, cholesterol esters and lipids of many other types which have a therapeutic effect per se and which can be advantageously formulated as an emulsion, based on the glycosylglycerides. In this case, the bioactive material is the oily material. The pharmaceutical composition may be formulated for oral, enteral, parenteral, rectal, vaginal, topical, ocular, nasal or aural administration to animals, especially mammals, including humans.

A pharmaceutical composition may be as follows: An active substance in a therapeutically effective amount; a glycosyl glyceride emulsifier, 0.1-5.0% by weight of the total composition; an oily material, 5-50% by weight of the total preparation. The isotonic agent is e.g. glycerol, but can also be any other isotonic agent in an isotonically effective amount.

The emulsions based on glycosylglycerides are surprisingly stable preparations compared to phospholipid emulsions made from egg lecithin or soy lecithin. Shake tests, which destroy phospholipid emulsions, have no effect on glycosylglyceride emulsions.

The glycosylglyceride emulsions also show a narrow and even particle size distribution, which normally poses a problem with phospholipid emulsions. Commercially available fat emulsions based on egg lecithin often have the problem of containing excessive particles, which can lead to problems such as the phenomenon 518 825 = ::. F: 1 :. . 6 creaming or appearance of oil droplets on the surface.

The glycosylglyceride emulsions are also surprisingly stable to sterilization by autoclaving in a standard autoclave. Commercially available fat emulsions often need to be autoclaved in special rotating autoclaves, which is a technical problem. The use of standard methods for autoclaving constitutes a pronounced industrial improvement achieved by the invention.

Examples For the following examples, glycosylglycerides have been prepared as described below. The glycosylglyceride material consists mainly of digalactosyldiacylglycerols (DGDG) but also of monogalactosyldiacylglycerols (MGDG).

Soybean oil and medium chain triacylglycerol oil (MCT oil) are used as model oils. However, the type of oily material is not critical to the attainment of the specific advantages of the present invention.

The oils used in Examples 1-7 were manufactured by Karlshamns AB and chromatographically purified by Karlshamns LipidTeknik AB.

Commercially available chemicals were used without further purification unless otherwise stated. Deionized, membrane-filtered water is used in all preparations.

The emulsions were prepared by high pressure homogenization (Mini-Lab 8.30 H homogenizer, Rannie, Denmark). The particle size distribution in the obtained emulsions was determined by dynamic light scattering (Zetasizer 4, Malvern Instruments, England) at room temperature. The measurements were performed at an angle of 90 ° using a ZET5110 size measuring cell and multimodal analysis. Data are reported as Z averages.

Process for the preparation of glycosylglycerides used as emulsifier 200 kg of oat kernels (Kungsörnen, Sweden) were ground and extracted with 1000 l of 95% ethanol at 70 ° C for 3 hours in an extraction tank with stirring. The slurry was centrifuged while still hot and separated from solid particles. The liquid fraction was evaporated at a maximum of 60 ° C to give about 10 kg. = u. .of 7 extracts in the form of a light brown oil.

The carbohydrates were removed as follows: 10 kg of the extract were thoroughly mixed with 10 l of hexane (hexane of polymerization grade, distillation range 65-70 ° C, Shell) and 50 l of 70% aqueous ethanol. The mixture separated into two phases overnight. The lower, more polar phase, which contained the carbohydrates was discarded. The lipids were in the upper phase.

The upper phase, which amounted to about 20 l, was applied to a stainless steel column of 30 cm x 20 cm (ID xh) with a volume of about 14 l and containing 6.25 kg of silica gel (Matrex Siloca Si, particle size 20). -45 mm, pore diameter 60 Å, from Amicon Corp., Danvers). The column was heated to 50 ° C and then washed with 30 L of a hexane: isopropanol mixture, 90:10, to remove any triglycerides.

The glycosylglyceride material was then eluted from the column with 20 l of a mixture of hexanesisopropanol, 60:40, to give a glycosylglyceride fraction. Evaporation of this fraction gave about 700 g of glycosylglycerides. The most important lipid class was DGDG,> 70% (of the surface), according to analysis by high-resolution liquid chromatography. The glycosylglycerides were then lyophilized to give a free flowing powder.

Example 1. Preparation of a 10% fat emulsion (MCT oil) An oil-in-water (o / v) emulsion was prepared which contained the following ingredients: Ingredient% (w / w) Emulsifier 0.5 Triacylglycerol with medium 10.0 long chains Glycerol, 99% (w / w) 2.5 Water 87.0 The emulsifier, ie. the glycosylglycerides, were dispersed in the oil.

Glycerol and water were mixed. The oil phase and the aqueous phase were preheated to 70 ° C and 85 ° C, respectively. The aqueous phase was added to the oil phase with mixing under vigorous shear at 18,000 rpm for 6 minutes. The pre-emulsion was adjusted to pH 8 using a 2 M NaOH solution under this mixture with vigorous shaking. The 518 825 * šfšfffš-If ...... .- 8 was then homogenized at 80 MPA and 50 ° C for six cycles.

Example 2. Preparation of a 203 g fat emulsion (MCT oil) An oil-in-water (o / v) emulsion was prepared which contained the following ingredients: Ingredient% (w / w) Emulsifier 1.0 Triacylglycerol with medium , 1 long chains Glycerol, 99% (w / w) 2.5 Water 76.4 The emulsifier, ie. the glycosylglycerides, were dispersed in the oil.

Glycerol and water were mixed. The oil phase was preheated to 90 ° C and the aqueous phase to 50 ° C. The oil phase was added to the aqueous phase while mixing under vigorous shear at 14,000 rpm for 4 minutes. The pre-emulsion was adjusted to pH 7.5 by adding a 2 M NaOH solution under this mixture while shaking vigorously. It was then homogenized at 80 MPa and 45 ° C for five cycles.

The emulsion formed had an average particle size of 213 nm. This average size did not change significantly after autoclaving (121 ° C, 20 min) and shaking (120 h, 150 cycles / min).

Example 3. Preparation of a 30% fat emulsion (MCT oil) An oil-in-water (o / v) emulsion was prepared using the following ingredients.

Ingredient% (w / w) Emulsifier 1.5 Triacylglycerol with medium 30.1 long chains Glycerol, 99% (w / w) 2.5 Water 65.9 The emulsifier, ie. the glycosylglycerides, were dispersed in the oil.

Glycerol and water were mixed. The oil phase was preheated to 67 ° C and the aqueous phase to 55 ° C. The oil phase was added to the aqueous phase while mixing under vigorous shear at 13,000 rpm for 6 minutes. The pre-emulsion was adjusted to pH 8 using a 2 M NaOH solution under this mixture with vigorous shaking. It was then homogenized at 80 MPa and 40 ° C for six cycles to give an average particle size of 200 nm.

A portion of the resulting emulsion was heat sterilized in a standard bench autoclave at 121 ° C for 20 minutes. After the heat treatment, a particle size of 209 nm could be determined, which shows that the emulsion droplets were not significantly affected during the process.

Another portion of the emulsion was exposed to a shake test at 150 cycles / min for five days. No aggregation of emulsion droplets and subsequent creaming could be observed after the shake test. The average particle size, 206 nm, showed that the emulsion was very stable against shaking at high frequency for a long period of time. The heat-sterilized emulsion was also subjected to the same shaking test without any appreciable change in behavior during the experiment.

An emulsion based on 1.2% (w / w) egg phospholipids and 20% (w / w) soybean oil did not pass the shake test at the same frequency; already after 1-2 hours, creaming could be observed on top of the egg phospholipid emulsion.

Example 4. Preparation of a 39% fat emulsion (MCT oil) An oil-in-water (o / v) emulsion was prepared using the following ingredients.

Ingredient% (w / w) Emulsifier 2.0 Triacylglycerol with medium- 39.4 long chains Water 58.6 The emulsifier, ie. the glycosylglycerides, were dispersed in the oil.

The water and oil phases were preheated to 70 ° C and the oil was added to the aqueous phase with mixing under vigorous shaking at 16,000 rpm for 7 minutes. The pre-emulsion was adjusted to pH 8 using a 2 M NaOH solution under this mixture with vigorous shaking.

It was then homogenized at 82 MPa and 50 ° C for six cycles of 5 hours.

This formulation gave an emulsion with a slightly creamy consistency and a narrow size distribution with an average particle size of 206 nm.

Example 5. Preparation of a 503 g fat emulsion (MC2 oil) An oil-in-water (o / v) emulsion was prepared which contained the following ingredients: ßgstågdsdgl § (w / w) Emulsifier 2.5 Triacylglycerol with medium , 3 long chains Glycerol, 99% (w / w) 2.5 Water 44.7 The emulsifier, ie. the glycosylglycerides, were dispersed in the oil.

Glycerol and water were mixed. The oil phase was preheated to 60 ° C and the aqueous phase to 75 ° C. The oil phase was added to the aqueous phase with mixing under vigorous shear at 20,000 rpm for 4.5 minutes. The pre-emulsion was adjusted to pH 7.0 with the addition of a 2 M NaOH solution under this mixture with vigorous shaking. It was then homogenized at 80 MPa and 55 ° C for five cycles.

The emulsion formed had a fairly high viscosity ("yogurt-like") with an average particle size of 235 nm.

Example 6. Preparation of a 20% fat emulsion (MCT3 soybean oil) An oil-in-water (o / w) emulsion was prepared containing the following ingredients: Ingredient% (w / w) Glycosylglycerides 1.0 Phosphatidylcholine from soybean 1.0 beans Soybean oil 10.0 Triacylglycerol with medium 10.0 long chains Glycerol, 99% (w / w) 2.5 Water 75.5 11 The glycosylglycerides and soybean phosphatidylcholine were dispersed in the oil mixture. Glycerol and water were mixed. The oil phase was preheated to 65 ° C and the aqueous phase to 55 ° C. The aqueous phase was added to the oil phase with mixing under vigorous shear at 11,000 rpm for 9 minutes. The pre-emulsion was adjusted to pH 8.1 by adding a 2 M NaOH solution under this mixture with vigorous shaking. It was then homogenized at 80 MPa and 46 ° C for five cycles. The emulsion formed had an average particle size of 262 nm and did not change significantly after autoclaving.

Example 7. Preparation of a 20§ fat emulsion (soybean oil) An oil-in-water (o / v) emulsion was prepared using the following ingredients: Ingredient% (w / w) Emulsifier 1.5 Soybean oil 20.0 Glycerol .99% (w / w) 2.5 Water 76.0 The emulsifier, i.e. the glycosylglycerides, were dispersed and hydrated in a portion of the water. Glycerol and the remainder of the water were then added and mixed. The aqueous dispersion was subjected to high pressure homogenization for two cycles at 60 MPa and 40 ° C. The soybean oil, preheated to 40 ° C, was added to the aqueous dispersion while mixing with vigorous shaking at 13,000 rpm for 10 minutes. The pre-emulsion was then homogenized at 80 MPa and 40 ° C for six cycles. After cooling to room temperature, the emulsion was adjusted to pH 7.2 using a 2 M NaOH solution.

Table 1 summarizes the average particle size in nm of the emulsions described in Examples 1-7. 518,823 u; u | n ». ,, I n n U. "" .¿. u nos nu 12 Table 1 Example Oily material Initial After auto- After shake- no emulsion piano test 1 10% MCT 243 2 20% MCT 213 226 222 3 30% MCT 200 209 206 4 39% MCT 206 216 5 50% MCT 235 6 10% MCT; 10% 262 266 soybean oil 7 20% soybean oil 400 Conclusions According to the invention it has been found that it is possible to produce remarkably stable oil-in-water emulsions based on the glycosylglycerides which meet the important and necessary requirements of being able to autoclave and that be resistant to harsh mechanical treatment. The emulsions have particle size distributions suitable for parenteral and intravenous use. The emulsions do not exhibit any unpleasant odor or taste and are remarkably stable to oxidation. The present invention provides an alternative to phospholipid emulsions which provides concrete advantages over such emulsions.

Claims (9)

1,518,825 fr; -s 4 Q _. ._ ...........,. PATENT REQUIREMENTS An oil-in-water emulsion comprising 0.01-50% by weight of the total preparation, preferably 0.1-10%, of an emulsifier and 0.1-70% by weight of the total preparation of a oily material emulsified in an aqueous solution, characterized in that the emulsifier is a galactosyl glyceride of the general formula R1-o-'cnz Rz -o-on nzc-o II galactose-cH2o-R3 wherein R1 and R2 are independently saturated or unsaturated fatty acid residues having 10-22 carbon atoms, preferably 16-18, and 0-3 double bonds, and R 3 is hydrogen or a galactose group; or a mixture thereof, optionally with phospholipids or other emulsifiers. A stable emulsion according to claim 1, which has an average particle size of 200-400 nm. Use of an emulsion according to any one of claims 1-2 as a carrier for an active substance in a pharmaceutical product, nutritional product, cosmetic product, food or agricultural product. Use of an emulsion according to any one of claims 1-2 as a carrier for an active substance. A pharmaceutical composition comprising an oil-in-water emulsion according to any one of claims 1-2 in combination with a bioactive substance. A pharmaceutical composition according to claim 5, wherein the oily material is a triacylglycerol oil, preferably a medium chain triglyceride oil (MCT oil) or a bioactive substance. f 7. ~. | A pharmaceutical composition according to claim 5 or 6, comprising a bioactive substance in a therapeutically effective amount, a glycosylglyceride emulsifier, 0.1-5.0% by weight of the total preparation, an oily material , 5-50% by weight of the total preparation, an isotonic agent in an isotonically effective amount. A pharmaceutical composition according to any one of claims 5-7, for oral, enteral, parenteral, rectal, vaginal, topical, ocular, nasal or aural administration. Use of a glycosylglyceride of the general formula R1-o-one, R2-o-en Hzc-o II galactose cnzo-R3 wherein R1 and R2 are independently saturated or unsaturated fatty acid residues having 10-22 carbon atoms, preferably 16- 18, and 0-3 double bonds, and R 3 is hydrogen or a galactose group; or a mixture thereof, as an emulsifier in an oil-in-water emulsion, optionally in combination with phospholipids or other emulsifiers.