sensory properties in consumer products
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Controlled delivery of water-insoluble active ingredients in air from hydrogel matrices
C. Dispenza1,2, G. Giammona3, M. Licciardi3, C. Lo Presti1, M. Ricca1, C. Spadaro1
1Dept. of Processing and Materials Chemical Engineering (DICPM)
2Interdept. Research Centre on Composite Materials (CIRMAC)
Dipartimento di Chimica e Tecnologie Farmaceutiche
SIBPA, Palermo 17-22 September 2006
logoUniversità di Palermo
Contents:
The context
“Functional” hydrogels from colloidal systems
“Functional” hydrogels obtained through ionising irradiation
Release behaviour of a model fragrance
Conclusions
Sensory properties in consumer products
CONSUMER PRODUCT
Informed choices
Value-based choices
Impulse-based choices
CONSUMER BEHAVIOUR
performance
appearance
experience
• Foods• Cosmetics• Smoke• Housefield• Paints and coatings
• Paper• Textiles• Automotive • ICT• …
Major investor for research & development in the field of smart delivery of fragrances: Nissan!
• Essential oils• Aroma chemicals• Absolutes• Balsams• Concentrated oils• Essences• Extracts• Resins• Infusions
Polymers delivering olfactory sensations
• Aromatic esters
• Aliphatic esters
• Ethers
• Ketones
• Alcohols
Micelles Vesicles
ACTIVE INGREDIENTS
d= 100 - 600 m
INCORPORATED / ENCAPSULATED INTO A POLYMER
dry powders
creams, foams, lotions, ect.
DISPERSED/EMULSIFIED
BARRIER MATERIALS
DIFFERENT ARCHITECTURES FORMED BY BLOCK-COPOLYMERS IN WATER
Bicontinuous phases Hexagonally packed vescicles Lamellae
• INERT, BIOCOMPATIBLE, BIODEGRADABLE
• HIGH LOADING CAPACITIES(non equilibrium systems & processes)
• Ensuring SYNCHRONISATION between the required TIME FOR THE SENSORIAL EFFECT and the actual RELEASE PROFILE
• Ensuring SITE OF RELEASE RECOGNITION
• Relatively STABLE TO STORAGE conditions over a long period of time
(for cosmetics: 2-3 years)
Polymers as delivery devices, some requirements…
Hydrogels by definition
High water content (>20% - 1000%)3D network structure with soft consistencyElastic structure with a memorised reference configuration
Linear polymer strands
PHYSICAL GEL
CHEMICAL GELS
“Virtual” cross-links formed by chain entanglements, electrostatic forces, hydrogen bonds
T, pH, solvents+ chem. reaction
+ chemical cross-links
DISSOLUTION SWELLING
+ H2O
T, pH, solvents
Tridimensional polymeric networks:
Ionising irradiation
Water + cross-linked polymer =
Water + water-soluble monomers and/or polymers
“Functional” hydrogels through ionising irradiation
CROSSLINKING of hydrophilic MONOMERS and POLYMERS (+ X-linking agents + initiators/catalysts) by thermal activation
• Complementary reactive groups: hydroxyl-aldehydes, amine-carboxylic acid, isocyanate-OH / NH2 etc.
• Reactive double bonds
crosslinksP
POHHPOH
eOHHOH aq
2
2 ,,Ionising
irradiation
IONIZING IRRADIATIONIONIZING IRRADIATION
The other way…
…to create reactive sites andpromote reactivity!
= IN SITU “FUNCTIONAL” HYDROGEL
“Functional” hydrogels through ionising irradiation
H y d r o p h i l i c m o n o m e r s a n d / o r p o l y m e r s
D i s p e r s e d “ o b j e c t s ” f r o m 5 u p t o 5 0 0 n m o f a v e r a g e d i a m e t e r
I R R A D I A T I O NW a t e r+ W a t e r
C r o s s l i n k e d p o l y m e r
“Active” ingredient:
• Water-insoluble molecules•heat sensitive and/or volatile
• Water-insoluble polymers(1,2)
•conductive polymers obtained via dispersion polymerisation
Water- insolubleActive Ingredient
Polymeric surfactant
Ionising irradiation
1 C. Dispenza, C. Lo Presti, C. Belfiore, G. Spadaro, S. Piazza, Polymer, 47, 961-971, 2006.
2 C. Dispenza, M. Leone, C. Lo Presti, F. Li Brizzi, G. Spadaro, V. Vetri, Journal of Non-Crystalline Solids, 352 (2006) 3835–3840.
DISPERSED “OBJECT”
flavours (aromas) and fragrances
H y d r o p h i l i c m o n o m e r s a n d / o r p o l y m e r s
D i s p e r s e d “ o b j e c t s ” f r o m 5 u p t o 5 0 0 n m o f a v e r a g e d i a m e t e r
I R R A D I A T I O NW a t e r+ W a t e r
C r o s s l i n k e d p o l y m e r
‘In-house’ developed, flexible polymer chemistry from..
HC
C
NH
NH
HC C
CH2
O
NH CH2 CH2 OH
C O
NH
O
C
O
NH CH2 CH2 OH
CH2
-POLY(N-2-HYDROXYETHYL)-D,L-ASPARTAMIDE
PHEA
Grafting of double bonds for easy of crosslinking
Grafting functional groups for stimuli sensitivity
Co60 gamma irradiator
( IGS-3 at Palermo University)
60 Co
1.33 MeV
60Co = 60 Ni + e -+ ’1.17 MeV
DOSE : 2,5-3,5 kGyDOSE RATE: 0,5 kGy/h
Gray: 1J of energy absorbed by 1 Kg of matter
Experimentals
PHEA + GMA = PHG
PHG + water + rays= PHG hydrogel
(Derivatisation degree= 0,3)
5% wt/vol PHG/water
H y d r o p h i l i c m o n o m e r s a n d / o r p o l y m e r s
D i s p e r s e d “ o b j e c t s ” f r o m 5 u p t o 5 0 0 n m o f a v e r a g e d i a m e t e r
I R R A D I A T I O NW a t e r+ W a t e r
C r o s s l i n k e d p o l y m e r
‘In-house’ developed, flexible polymer chemistry from..
HC
C
NH
NH
HC C
CH2
O
NH CH2 CH2 OH
C O
NH
O
C
O
NH CH2 CH2 OH
CH2
-POLY(N-2-HYDROXYETHYL)-D,L-ASPARTAMIDE
PHEA
Grafting of double bonds for easy of crosslinking
Grafting functional groups for stimuli sensitivity
Co60 gamma irradiator
( IGS-3 at Palermo University)
60 Co
1.33 MeV
60Co = 60 Ni + e -+ ’1.17 MeV
DOSE : 2,5-3,5 kGyDOSE RATE: 0,5 kGy/h
Gray: 1J of energy absorbed by 1 Kg of matter
Experimentals
PHEA + GMA = PHG
PHG + water + rays= PHG hydrogel
(Derivatisation degree= 0,3)
5% wt/vol PHG/water
Transparent – “reversible”
Model active
Tetra- HydroGeraniol (THG): 3-7 dimethyl octanol
Polymeric surfactantBRIJ 58P: polyoxyethylene (20) cetyl ether
Experimentals
Emulsions & microemulsions
20 % vol THG/water; 2 % wt/vol BriJ/water1% vol THG/water; 3 % wt/vol BriJ/water
20 %vol THG/water; 2 %wt/vol BriJ/water + 5 %wt/vol PHG1 %vol THG/water; 3 %wt/vol BriJ/water + 5 %wt/vol PHG
Hydrogels
5 %wt/vol PHG at 2.5 kGy5 %wt/vol PHG at 3.5 kGy
3 %wt/vol BriJ/water + 5 %wt/vol PHG
20 % vol THG/water; 2 % wt/vol BriJ/water + 5 %wt/vol PHG (stirred)1 %vol THG/water; 3 % wt/vol BriJ/water + 5 %wt/vol PHG
Effect of irradiation on chemical structure
Stability prior and upon irradiation
Effect of irradiation on chemical structure
Insoluble fractionsSwelling ratios
Fragrance release behaviour
CHARACTERISATIONSMATERIAL SYSTEMS
Flux meter
in out
“STATIC” HEAD-SPACE
“DYNAMIC” HEAD-SPACE
GC analysis
GC analysis
Air supply
Experimentals
FRAGRANCE RELEASE BEHAVIOUR37°C
37°C
Cum
ula
tive T
HG
rele
ase
d,
ppm
“Static” head-space release behaviour
Time, [hr]
0
200
400
600
800
1000
0 10 20 30 40 50 60
0 kGy
2,5 kGy
3,5 kGy
Head space saturation
EMULSIONS
19753,5BriJ58P-PHG-water
27652,5BriJ58P-PHG-water
9913,5PHG-water
10862,5PHG-water
Swelling ratio [Ws/Wd]
Insoluble fraction, [%]
Dose [kGy]System
Cum
ula
tive T
HG
rele
ase
d,
ppm
“Static” head-space release behaviour
Time, [hr]
0
200
400
600
800
1000
0 10 20 30 40 50 60
0 kGy
2.5 kGy
3,5 kGy
Head space saturation
EMULSIONS
Cum
ula
tive T
HG
rele
ase
d,
ppm
0
100
200
300
400
500
600
700
800
900
0 10 20 30 40 50 60 70
Time, [hr]
0 kGy
2,5 kGy
3,5 kGy
Head space saturation
MICRO-EMULSIONS
“Dynamic” head-space release behaviour
Time, [hr]
Cum
ula
tive T
HG
rele
ase
d,
[mg]
0
1
2
3
4
5
6
7
8
9
0 10 20 30 40 50
0 kGy
3,5 kGy
2,5 kGy
Total amount of THG loaded
MICRO-EMULSIONS
0.00
0.20
0.40
0.60
0.80
1.00
1.20
0 10 20 30 40 50
Time, [hr]
Weig
ht
loss
, [
g]
0 kGy
3,5 kGy
2,5 kGy
Initial weight of water + THG
Cu
mu
lati
ve T
HG
rele
ased
, [m
g]
4,7
4,9
5,1
5,3
5,5
5,7
5,9
30 35 40 45 50 55
Time, [hr]
Re-hydration of the surface
OFFON ON OFF
2,5 kGy
SURFACE-REGULATED RELEASE MECHANISMSURFACE-REGULATED RELEASE MECHANISM
hydration
“ON-PHASE” OF THE RELEASE“OFF-PHASE” OF THE RELEASE
de-hydration
SKIN
“REVERSIBLE”!
• the faster the hydrogel looses water the sooner the skin is formed!
• the looser is the polymeric network the faster is the release of water
• water represent, by large, the main volatile component released
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1
0 10 20 30 40 50
Time, [hr]
W(t)
W0
0 kGy
3,5 kGy
2,5 kGy
Dotted line: water + THGSolid line: THG
SURFACE-REGULATED RELEASE MECHANISMSURFACE-REGULATED RELEASE MECHANISM
Conclusions:
Ionising irradiation can be a stimulating tool to obtain “functional” hydrogels from water-soluble polymeric precursors.
Crosslinking degree and density can be controlled by tuning irradiation conditions, thus affecting the water retention properties of the gels.
Oil insoluble fragrances can be incorporated by coupling irradiation and emulsification techniques.
Hydrogel formation can prevent macroscopic phase-separation of otherwise unstable systems.
The hydrogel network offers a diffusion barrier to the fragrance.
Water loss kinetics may be exploited for a on-off, surface hydration regulated, release behavior.
Controlled delivery of water-insoluble active ingredients in air from hydrogel matrices
SIBPA, Palermo 17-22 September 2006
CONTACT DETAILSClelia DispenzaDipartimento di Ingegneria Chimica dei Processi e dei MaterialiUniversità degli Studi di PalermoTel +39 091 6567210Fax+ 39 091 6567280dispenza@dicpm.unipa.it
THANK YOU
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