AU704264B2 - Incorporation of a water-soluble active principle in a lipid - Google Patents

Abstract

A water soluble active material (I) is incorporated into a fatty material (II) by the following method: a) lecithin is treated to give a fraction practically free from phosphatidyl choline; b) an aqueous solution of (I) is incorporated into a mixture of the lecithin fraction and (II) under vigorous agitation and in sufficient quantity to ensure hydration of the lecithin fraction, thus forming a heterogeneous mixture, and c) this mixture is dried to form a homogeneous product.

Description

1

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: Actual Inventor: Address for Service: SOCIETE DES PRODUITS NESTLE S.A.

Raymond BERTHOLET SHELSTON WATERS Margaret Street SYDNEY NSW 2000 "INCORPORATION OF A WATER-SOLUBLE ACTIVE PRINCIPLE IN A LIPID" Invention Title: The following statement is a full description of this invention, including the best method of performing it known to us:- This invention relates to a process for incorporating a water-soluble active principle in a lipid and, more particularly, for stabilizing a water-soluble antioxidant in a lipidic phase.

The majority of oils and certain fats used in food, cosmetic and pharmaceutical products are rich in polyunsaturated fatty acids and, because of this, are particularly sensitive to oxidation. Their stability can be improved by the addition of synthetic antioxidants such as, for example, BHA (butyl hydroxyanisole), BHT (butyl hydroxytoluene) or TBHQ (tert.butyl hydroquinone).

Unfortunately, the harmlessness of these compounds is questionable.

Attempts have been made to replace them with natural 15 antioxidant compounds of the fat-soluble type such as, for example, the tocopherols or ascorbyl palmitate or of the water-soluble type such as, for example, ascorbic acid, vegetable extracts, organic acids or amino acids.

In the case of the water-soluble compounds, an emulsi- 20 fier, such as a phospholipid for example, has to be used for incorporating the water-soluble antioxidants in the oils in the form of micelles.

S. By virtue of their structure, the phospholipids are capable of creating associations with certain water- 25 soluble compounds to form micelles which, for their part, are fat-soluble.

The incorporation of vitamin C or other watersoluble compounds in oils using phospholipids is known, for example, from EP-A-0 326 829. Unfortunately, this known process uses an organic solvent, for example ethanol, which promotes the formation of a single phase in view of its hydrophilic and lipophilic properties. In addition, the process in question which uses an unfrac- -2tionated soya lecithin is attended by the disadvantage that problems of colour, odour and flocculation in storage cannot be avoided.

According to US-A-5,084,289, inverse micelles, i.e. micelles in which the continuous phase is the lipophilic phase, are formed by dissolving in an oil a phospholipid and then a small quantity of an aqueous solution containing a water-soluble antioxidant, for example vitamin C, in a high concentration. The mixture is stirred to form inverse micelles, a single phase thus being obtained. The small quantity of aqueous phase relative to the lipidic phase makes homogenization difficult or even virtually impossible on a large scale. In addition, it is only possible by this process to incorporate substances highly soluble in water, for example vitamin C, and not sparingly watersoluble substances such as, for example, ethylene dinitrotetraacetic acid (EDTA).

S. Finally, this process does not avoid the appearance of undesirable colours and odours in storage because the lecithin is not fractionated.

It has now surprisingly been found that these disadvantages can be completely 15 eliminated by using a lecithin fraction substantially free from phosphatidyl choline.

Accordingly, the present invention relates to a process for incorporating a water- *soluble active principle, the active principle being a cosmetic agent, a dermatological agent or an antioxidant, in a fat to be protected from oxidation in the presence of lecithin, wherein the lecithin is treated to produce a lecithin fraction substantially free from phosphatidyl choline, an aqueous solution of the water-soluble active principle is incorporated in the mixture of this fraction and fat in liquid form with vigorous stirring in a quantity sufficient to hydrate the lecithin fraction to form a heterogeneous mixture and the mixture obtained is dried and thus becomes homogeneous.

I Sl01 -0i DOC :n the context of the present invention, a "lecithin fraction substantially free from phosphatidyl choline" is understood to be a fraction obtained from commercial Lecithin, for example soya, by a treatment which enables tne phosphatidyl choline to be separated from the other constituents, such as phosphatidyl ethanolamine, phosphatidyl inositl and phosphatidic acid, hereinafter referred to as "other PLS" (other phospholipids).

In a first embodiment, the commercial lecithin is treated in solution in the oil with a bleaching earth as adsorbent, after which the oil thus treated is separated.

In a second embodiment, which is preferred, the lecithin is treated in solution in a mixture of organic solvents by liquid chromatography in a column of silica gel in known manner and the fraction containing the other ?LS, which is also freed from most of the triglycerides, is collected.

The water-soluble active principles envisaged in o* accordance with the invention are cosmetic 20 or derr.atological agents or water-soluble antioxidants.

S They include, for example, conventional antioxidants, for example vitamin C, vegetable extracts, for example rcsemary, green tea, organic acids, for example hydroxy acids, such as citric acid,, phenolic acids, for example caffeic, quinic and chlorogenic acids, caffeine, amino acids, phenyl indanes and sequestering agents, for examole citrates or EDTA.

The fat to be protected against oxidation is rich in unsaturated fatty acids, more particularly polyunsatura- :30 ted fatty acids. The fat may be a vegetable oil, for example sunflower oil, wheat germ oil, grapeseed oil, corn oil, safflower oil, olive oil, evening primrose oil, borage oil and blackcurrant seed oil, or an animal oil, for example chicken fat, butter oil, a marine animal oil, more particularly fish oil.

-4- Preferably, the incorporation of the water-soluble active principle takes place with vigorous st-rring at a temperature above 60°C and more preferably at a temperature of the order of 80 0 C. The water-soluble active principle may be introduced in the form of an aqueous solution or, alternatively, in dry form, in which case water is subsequently added. The quantity of water in the mixture should be sufficient to hydrate the quantity of lecithin fraction which it contains. Preferably, it represents 2 to 8% by weight of the mixture and, more preferably, approximately 5% thereof. Preferably, this operation takes place over a period of 10 to 30 minutes in the absence of air, for example in a nitrogen atmosphere, which results in the formation of a heterogeneous mixture.

Preferably, the water is then eliminated from the heterogeneous mixture by heating in vacuo, preferably to 60 to 90°C and advantageously to 60 to 70 0 C under a vacuum of 0.5 to 35 mbar. Preferably, a homogeneous and stable micellar phase is formed.

The invention is illustrated by the following Examples in which parts and percentages are by weight, unless otherwise indicated.

15 Example 1 A refined soya lecithin low in heavy metals (Top-lecithin 200®) and containing of phospholipids (referred to hereinafter as PLS) is dissolved under nitrogen in a sunflower oil (SFO).

The solution is then treated with a bleaching earth (Tonsil Optimum FF®) for minutes at 85 to 90°C, under a pressure of 35 mbar and in the presence of a foam inhibitor (Rhodosil 70414®), the quantity of adsorbent corresponding to four times the quantity of phospholipids, after which the solution is separated from the adsorbent by filtration.

-The quantities shown in Table 1 below of vitamin C t806 1 -00 DOC and EDTA in solid form and then 5% of demineralized water are subsequently added to the solution. After vigorous stirring under nitrogen for 15 minutes at 80"C, a heterogeneous mixture is obtained and is then dried for minutes at 80-90'C under a pressure of 35 mbar and then mbar and filtered. A homogeneous micellar phase is obtained.

The stabilized oil (la) is evaluated by comparison with the same, unstabilized oil (lb) and with an oil stabilized with a commercial lecithin which has not been treated with bleaching earth (Ic): From the point of view of their stability to oxidation as measured by the Rancimat® accelerated oxidation test at 110°C. The induction times obtained, expressed in h, 15 represent the OSI (oil stability index) values.

From the point of view of their stability in storage at 15"C by visual and olfactory assessment.

The results obtained are set out in Table 1 below: Table 1 20 Test PL Vit. C EDTA Treat- OSI, Colour mg/kg mg/kg mg/kg ment 110°C,h la 10000 1000 200 Yes 19.5 Yellow lb 5 Light yellow 25 Ic 10000 1000 200 No 17.5 Orangeyellow It can be seen that the treatment of lecithin with a bleaching earth improves its colour and increases its stability to oxidation.

Examples 2-10 SFO is stabilized in the same way as in Example 1 using vitamin C in conjunction with various sequestering agents in various quantities. The OSI values of unstabilized SFO (2a) and SFO containing the PL fraction treated with the adsorbent (2b) are measured by way of comparison.

The protection factor which corresponds to the quotient: PF OSI of the stabilized oil/OSI of the unstabilized oil (this quotient represents the increase in the induction time), is calculated from the OSI values.

The results are set out in Table 2 below: Table 2 Exam- PL ple mg/kg o Vit.C Sequesmg/kg trant,

SA

1000 2a 2b 2 5000 5000 3 5000 1000 EDTA 4 5000 1000 EDTA 5000 1000 EDTA 6 5000 1000 EDTA Na2 25 7 5000 1000 Citric acid 8 5000 1000 Citric acid Na3 9 5000 1000 Citric acid Na3 5000 1000 EDTA citric acid Na3 SA OSI PF Stability mg/kg 110*C, at h after 5 1 Clear 5.7 1.14 Clear 19 3.8 Slightly cloudy 100 22.5 4.5 Slijhtly cloudy 200 22 4.4 Clear 400 20 4 Clear 200 21 4.2 Slightly cloudy 200 17 3.4 Slightly cloudy 200 20.5 4.1 Slightly cloudy 400 16 3.2 Clear 200 21.8 4.36 Slightly cloudy It can be seen that the use of PL on its own is not sufficient to stabilize the oil (2b compared with 2a).

Examples 11-15 Following the procedure of Example 1, SFO stabilized with various ratios of vit.C to PL is evaluated for stability in storage, OSI and PF. The results are set out in Table 3 below by comparison with the unprotected oil (lla) and with the same oil to which 1.66% of a ternary mixture of vit.C, PL and vit.E in quantities of 1000 mg/kg vit.C, 4500 mg/kg PL and 500 mg/kg vit.E is added (lib).

r r Example

PL

mg/kg Vit.C EDTA mg/kg mg/kg la lib 4500 1000 +500 mg/kg vit.E 11 2500 1000 200 12 5000 1000 200 13 6600 1000 200 Table 3 Vit.C/ PLx100 22 40 20 15 13.3 10

OSI

110C, h 5 15.8 PF Stability at after 1 Clear 3.16 Slightly cloudy 14.7 2.94 Slightly cloudy 22 4.4 Slightly cloudy 20.8 4.16 Slightly cloudy 20 4 Clear 20 4 Clear 7500 10000 1000 200 1000 200 It can be seen that the use of a ternary mixture comprising vit.E does not improve the stability of the oil or its antioxidant properties in relation to the use of a mixture of PL and vit.C (llb compared with 11-15).

Accordingly, it may be concluded that the synergism between vit.C and vit.E already occurs with the vit.E 8 naturally present in SFO (corresponding to 760 mg/kg).

Accordingly, for vegetable oils naturally containing vit.E, the addition of more vit.E is not beneficial.

The stabilized oils were stored for 1 month at It was found that the oils stabilized with a ratio of vit.C to PL of greater than 13% became cloudy during that period. Accordingly, this ratio is preferably less than or equal to 13% to ensure optimal stability of the oil.

Examples 16-19 Following the procedure of Example 1, SFO stabilized with various quantities of vit.C (the ratio of vit.C to PL being constant) was evaluated for stability in storage, OSI and PF. The results obtained are set out in Table 4 below by comparison with the unprotected oil 15 (16a).

e STable 4 Exam- PL Vit.C EDTA Vit.C/ OSI PF Stability Sple mg/kg mg/kg mg/kg PLxl00 110*C, at h after 20 16a 5 1 Clear 16 2500 250 200 10 12.3 2.4 Clear 17 5000 500 200 10 16 3.2 Clear 18 7500 750 200 10 18 3.6 Clear 19 10000 1000 200 10 20 4 Clear S 25 Examples 20-24 Following the procedure of Example 1 to stabilize blackcurrant seed oil (BCSO), BCSO stabilized with a constant ratio of vit.C to PL is evaluated for stability in storage, OSI and PF. The results are set out in Table 5 below by comparison with the unprotected oil (20a) and with the same oil to which 1.66% of a ternary mixture of vit.C, PL and vit.E in quantities of 1000 mg/kg vit.C, 4500 mg/kg PL and 500 mg/kg vit.E (20b) has been added.

I

Example 20a 21 22 23 24

PL

mg/kg Vit.C EDTA mg/kg mg/kg Table Vit. E mg/kg 4500 1000 10000 10000 10000 10000 5000 1000 1000 1000 1000 500 500 500 400 400 500 200 Vit.C/ OSI PF Stability PL x 100"C, at 100 h after 4 1 Clear 22 17.5 4.38 Slightly cloudy 10 19.8 4.95 Clear 10 17.6 4.4 Clear 10 24 6 Clear 10 20.2 5.05 Clear 10 17.2 4.3 Clear

C

C

C

C o The results confirm those obtained with SFO (Examples 11 to 15), namely that the addition of vit.E does 15 not improve the stability of BCSO to oxidation but would actually seem to have a pro-oxidizing effect in a vegetable oil naturally containing around 750 ppm of vit.E (Example 22 compared with 23).

Example 20 Following the procedure of Example 1 to stabilize chicken fat free from vit.E, the chicken fat is evaluated for OSI, PF and colour with and without added vit.E by comparison with the unprotected fat. The results obtained are set out in Table 6 below.

PL

mg/kg 5000 5000 5000 5000 Vit.C mg/kg 500 500 500 500 Vit.E mg/kg Table 6 EDTA OSI mg/kg 120"C,h 2 7.3 PF Colour after Rancimat 1 Yellow 3.65 Yellow 8.25 Orange 5.25 Yellow 9.65 Yellow 250 100 250 100 16.5 10.5 19.3 The above results confirm that the synergistic effect between vit.C and vit.E exists when the fat to be protected does not naturally contain vit.E.

Example 26 A soya lecithin free from PC (other PLS fraction), which has been obtained as second fraction by liquid chromatography in a column of silica gel using a mixture of hexane, 2-propanol and water in a ratio of 1:1:0.1, is dissolved in SFO. A first fraction rich in phosphatidyl choline (PC fraction) is also collected.

Quantities of 10,000 mg/kg of each lecithin fraction, 1000 mg/kg of vit.C and 200 mg/kg of EDTA in solid form and then 5% of demineralized water are added to the oil. After vigorous stirring under nitrogen for 15 minutes at 20°C, a heterogeneous mixture is obtained and is dried for minutes at 80 to 90"C under a pressure of 35 mbar and then mbar. Filtration gives a homogeneous micellar phase in the case of the oil stabilized with the other PLS fraction.

By contrast, the PC fraction could not be dissolved in oil.

20 The OSI is then evaluated. The results are set out in Table 7 below.

Table 7 Phospholipids OSI 110"C Remarks PC Fraction The fraction could not 25 be dissolved in the oil Other PLS fraction 21 The fraction dissolves in the oil which is perfectly clear Examples 27-31 SFO is stabilized with various water-soluble antioxidant active principles in the same way as described in Example 26. The results are set out in Table 8 below. SFO with no additive (27a) was evaluated for 11 comparison.

The phenyl indanes were obtained from coffee by the extraction process according to European Patent Application No.94109355.1 filed on 17.06.1994 under the title "Phenyl indanes, a process for their production and their uses".

Example PL mg/kg Table 8 Active AP EDTA principle mg/kg mg/kg

(AP)

OSI

1100C,h 27a 27 28 29 30 10000 L-histidine 10000 L-cysteine 10000 Rosemary extract 10000 Green tea extract 1000 1000 1000 200 200 200 11.5 12 14 1 2.3 2.4 28 2.4 1000 200 12 10000 phenyl indanes 500 30.5 6.1 s Examples 32-33 20 The procedure described in Example 1 up to hydration of the PLS is used to stabilize an SFO. The drying step is carried out at various temperatures. The antioxidant properties and the colour of the stabilized oils are evaluated by comparison with the unstabilized oil (32a).

The results are set out in Table 9 below.

Table 9 Exam- Drying PL Vit.C EDTA OSI pie temper- without mg/kg mg/kg 110"C, ature PC h PF Colour measurement Lovibond 5.25" Y R 1 8.4 1.3 32a 32 80- 33 60- 5 10000 1000 400 10000 1000 400 21 4.2 43 4.8 22.8 4.56 18.5 2.7 It can be seen that the colour is less intense where drying is carried out at a lower temperature.

o r o r e o

Claims (6)

1. A process for incorporating a water-soluble active principle, said active principle being a cosmetic agent, a dermatological agent or an antioxidant, in a fat to be protected against oxidation, in the presence of lecithin, wherein the lecithin is treated to produce a lecithin fraction substantially free from phosphatidyl choline, an aqueous solution of the water-soluble active principle is incorporated in the mixture of this fraction and fat in liquid form with vigorous stirring in a quantity sufficient to hydrate the lecithin fraction to form a heterogeneous mixture and the mixture obtained is dried and thus becomes homogeneous.

2. A process as claimed in claim 1, wherein the lecithin is treated in solution in the fat in liquid form with a bleaching earth as adsorbent, after which the fat in liquid form thus treated is separated.

3. A process as claimed in claim 1, wherein the lecithin is treated in solution ii an organic solvent mixture by liquid column chromatography in known manner and the 15 fraction containing the phospholipids other than phosphatidyl choline, which is also freed from most of the triglycerides, is collected.

4. A process as claimed in claim 1, wherein the water-soluble active principles envisaged are cosmetic or dermatological agents or water-soluble antioxidants, more particularly conventional antioxidants, such as vitamin C, vegetable extracts, organic acids, amino acids and sequestering agents.

5. A process as claimed in claim 1, wherein the fat to be protected against oxidation *2 is rich in unsaturated fatty acids, more particularly sunflower oil, wheat germ oil, I W6i1 -00 DOC

14- grapeseed oil, corn oil, safflower oil, olive oil, evenin, ,mrose oil, borage oil, blackcurrant seed oil, chicken fat, butter oil or a marine animal oil. 6. A process as claimed in claim 1, wherein the water-soluble active principle is incorporated with vigorous stirring at a temperature above 7. A process as claimed in claim 1, wherein the active principle is incorporated in the form of an aqueous solution or in dried form, after which water is added to the mixture in a quantity sufficient to hydrate the quantity of lecithin fraction which it contains. 8. A process as claimed in claim 7, wherein the water represents 2 to 8% by weight of the mixture and in that hydration takes place for 10 to 30 minutes in the absence of air which results in the formation Af a heterogeneous mixture. 9. A process as claimed in claim 7, wherein the water is removed from the heterogeneous mixture by heating to 60-90°C under a vacuum of 0.5 to 35 mbar to obtain a homogeneous micellar phase. 10. A food, cosmetic or pharmaceutical product containing lipids, wherein its fatty 15 phase contains a water-soluble active principle in micellar form incorporated by the process claimed in any one of claims 1 to 9. 11. A process for incorporating a water-soluble active principle in a fat in the presence of lecithin which process is substantially as herein described with reference to any one of the Examples. DATED this 12th day of February 1999 SOCIETE DES PRODUITS NESTLE S.A. Attorney: PAUL G. HARRISON Fellow Institute of Patent Attorneys of Australia of BALDWIN SHELSTON WATERS IiIOl I ~iTO Abstract To incorporate a water-soluble active principle in a stable lipidic phase, the water-soluble active prin- ciple is added with stirring in the presence of water to a fat containing a lecithin fraction low in phosphatidyl choline and the heterogeneous mixture obtained is dried to form a homogeneous micellar phase. eO o **oo e