Vesicular Delivery Systems: from Phospholipids to Silicone

for Targeted Skin Sites

Vesicular Delivery Systems: from Phospholipids to Silicone

for Targeted Skin Sites

Joanna Newton, Stéphanie Postiaux and Shaow Lin

Dow Corning

Outline

Consumer needs – market analysis

Vesicular systems

Conclusion

Outline

Consumer needs – market analysis

Vesicular systems

Conclusion

Approach

Understand the trends of the market

Understand the needs of our customers’ customers

Discuss innovative options concepts with end users

Design innovative and appropriate technical solutions for future developments

Life style & market trends

High profile food scares inc BSE,

Bird Flu, Sudan 1

Concern over food origins

Increasing awareness of origins of C & T ingredients

Epidemics – SAR’s; MRSA and HIV –

substantial media coverage

Emphasis on hygiene

Awareness of lifestyle related

diseases

Lung Cancer

Skin Cancer

Heart Disease

Type 2 diabetes

Ageing Population

Disease prevention via diets, supplements and

avoidance of causal factors

Looking young as well as feeling young

Obesity – a global problem

Fad diets

Healthy Eating

New products developed

Food intolerances on the increase

Launch of free-from products

Growth of alternative sectors

consumers

Cosmetics and naturals

Consumers are focusing on what they put on their body

Ingredients become increasingly exotic – green tea;

argan oil; soya; rice

Natural drives growth in mature markets and sectors such as

US and Germany and bath and shower

Consumers demand natural and organic C & T products

Traditional Asian ingredients –Chinese herbs and ayurveda –

have global potential

Multi-nationals use effective marketing to emphasis ‘natural’

Emerging markets keen on natural products

Consumer needs and delivery systems potential impact

ImprovedAppearance

Prevent & Protect Recover & Repair

•Cleanse & Exfoliate•Color, Shine•Even Skin Tone•Smoothness, Strength•Target Sensory Profiles

•Barrier Protection•Anti-microbial •Sun Protection•Environmental Protection•Color Retention•Odor & Wetness

•Nourish & Enhance Health•Reduced Inflammation•Reduced Irritation•Acne Mgmt •Scar healing•Skin Disease

Benefits of delivery systems applied to consumer needs

Increased, durable & visible efficacy

Safe use, low irritation

Innovative textures

Improved sensory during

& after application

Enhanced appearance of skin &

hair

Stabilization & protection

Consumer

Formulators

Delivery system

Actives supplier

Selection of actives

Starting from market needs identified as :Anti-aging

UV protectionLong-lasting fragrances

FragrancesVitamins UV sunscreens

Benefits of delivery systems

Stabilization and protection of fragile ingredientsAchieve longer lasting/ substantive effect of activeCombination of multiple incompatible activesTargeted and sustained release of substancesOdor masking Conversion of liquids to solidsEtc.

No one single delivery system can meet all needs

TIME OF RELEASE

“Magic Moment””

End-ProductForm

Leave-onRinse-off

Substrate

SkinHairFabric

Delivery Benefits

StabilizationProtectionLong-lasting

Active Chemistry

SunscreensFragrancesVitamins

Outline

Consumer needs – market analysis

Vesicular systemsPhospholipid vesiclesSilicone vesicles

Conclusion

Vesicular systems

Amphiphilic bilayer material in waterPhospholipids OR Silicone Polyethers

Outline

Consumer needs – market analysis

Vesicular systemsPhospholipid vesiclesSilicone vesicles

Conclusion

Phospholipid vesicles

Liposomes

PS = 100 – 400 nm

Cell membrane similarity

Skin penetration or deposition

Delivery of lipophilic and hydrophilic actives

Quality and stability improvements

Soy bean lecithin

High phosphatidylcholine (PC) and linoleic acid content

Stable particle size and pH for 12 weeks at room temperature, 4°C and 40°C

High chemical and oxidative stability of unsaturated fatty acids in liposomal form

Half life 31P NMR method Rancidity method

Liposome parameters

Electron spin resonance

ESR = measurement of the alignment reaction of a free radical or unpaired electron towards an applied magnetic field

Used forStability of anti-oxidantsPenetration of anti-oxidantsStability of liposome in end formulation

Stability of anti-oxidants•Vitamin E & Vitamin C•Best in synergy•Best stability in liposomal form

0

10

20

30

40

50

60

70

80

90

100

Multivitamin in dispersion Multivitamin in liposome

Day OWeek 8

Penetration of anti-oxidants

•Radical scavenging in deep layers of epidermis•Activity where needed•Significant improvement after 20 min

90

100

110

120

130

140

150

160

170

control 5 min 10 min 20 min 30 min

Stability of liposomes•Hydrophobic spin label•Spectrum linked to freedom•Specific formulations can be screened

H2O Medium Medium

330 332 334 336 338 340 342 330 332 334 336 338 340 342330 332 334 336 338 340 342

Spin Label Liposome

H2OH2O MediumMedium MediumMedium

330 332 334 336 338 340 342 330 332 334 336 338 340 342330 332 334 336 338 340 342

Spin LabelSpin Label LiposomeLiposome

332 334 336 338 340

magnetic field, mT

Liposomes in H2O Liposomes in Gel label in Gel

Deposition – Sterical hindrance

• Liposomes stabilized by a polymeric lipid

• The protective layer prevents liposome from penetrating the skin

• Completely new concept for cosmetic applications(medical uses)

Outline

Consumer needs – market analysis

Vesicular systemsPhospholipid vesiclesSilicone vesicles

Conclusion

Silicone vesicles

• Unique

• PS = 100 – 400 nm

• Skin deposition

Delivery of lipophilic and hydrophilic actives

SPE structure

Rake – comb:Pendent polyether chains on silicone backbone

ABnCo-block organization – alternate of polyether and silicone blocks

Structural organization in water

Silicone vesicles•High molecular weight silicone polyethers•“Assembly-required” process•Kinetically stable vesicles

Encapsulation methods

Pre-load Method:

Actives dispersedinto vesicle-formingMedia

Actives entrappedwithin vesicles asthey form

Processes to give Si vesicles in finalaqueous medium

Post-load Method:

Actives dispersedinto pre-formed empty Si Vesicles

Proprietary process toEncapsulate activesInto Si vesicles

Vesicle bilayer and payload capacity

• Bilayer thickness, not the vesicle size, controls the active payload potential

• Increasing the vesicle bilayer thickness may increase active payload capacity

Silicone

Polyether

Lipophilic Actives

Highpayload

Lowpayload

How?

Examples

Active Class Actives Investigated Via Pre-load Method

Via Post-load Method

Lipophilic Vitamin A palmitate, Vitamin A

15 to 25% 15 to 25%

Fragrances* None < 10 %

Hydrophilic Vitamin C 20 to 50%** 20 to 50%**

Centella asiatica Plant Extract (solids)*

Low Low

Silico-philic Silicone Fluid Emollients 40 to 80% 40 to 70%

% Payload = [Actives] / [SPE solids + Actives] * 100%* Carrier fluid or solvent required for solid actives or highly polar actives

** Including those in the aqueous continuous phase

Outline

Consumer needs – market analysis

Vesicular systems

Conclusion

Conclusion

Wide variety of opportunities from consumers perspective

Wide variety of solutions from actives perspectivesAvailability/efficacyStabilitySafety

continued need for targeted delivery systems

Questions?

Thank you for your attention!