Persistence of Perfumes Coefficient:↑ nature of evaporation ↓ value of the threshold concentration Volatility Odor intensity Threshold value Odor tonality
Stability of Fragrance Change of odor Change of color
Stability factors Oxygen Light Temperature Humidity pH of product
Microcapsules Small particles (1-100 μm) Active agent surrounded by polymeric membrane Protect from oxidation (by heat, light, humidity, exposure to other substances) Prevent evaporation Control release rate
Microcapsules Released by –Mechanical –Temperature –Diffusion –pH –Biodegradation –Dissolution
Interfacial Polymerization Technique Monomer A+Monomer B (Hydrophobic liquid)(Hydrophilic liquid) Emulsifying Polymer AB Microcapsules+by product Stirring
Mechanical Techniques Spray dry Atomization etc.
Selection of the technique and shell material –Application of products –Physical and chemical stability –Concentration –Desire particle size –Release mechanism –Manufacturing cost
Microencapsulation process of limonene by interfacial polymerization. Rodrigues, et al., Ind. Eng. Chem. Res. 2008, 47, 4142–4147 Oil phase (HMDI)+Aqueous phase 1 (PVA) Formation of oil/water emulsion Urethane formation Aqueous phase 2 (PEG 400, DBTDL) Urea formation Aqueous phase 3 (EDA) Urea formation Aqueous phase 4 (HYD) Separation/Washing Polymerization and shell formation
Optical microscopy of microcapsules solution. Magnification: (a) 20x (b) 100x. Textile Impregnated with Microcapsules Characterization. SEM Analysis Rodrigues, et al., Ind. Eng. Chem. Res. 2008, 47, 4142–4147
Macrocapsules Diameter over 1000 mm show a different porosity distribution, T. Gum ํ et al. / Desalination 245 (2009) 769–775 Polysulfone capsules containing different vanillin concentrations.
Polymeric microspheres Fragrance incorporated in the polymer –Controlled by Initial loading of fragrance Ability of fragrance to diffuse through polymeric barrier –Driving force Interaction between fragrance molecule and polymer matrix Vapor pressure of fragrance
SEMandTEMimages of spheres obtained with the starting polymer concentrations of (a) 2000–16,000 ppm, (b) 18,000ppmand (c) 24,000– 28,000 ppm. (a) SEM, (b) TEM and (c) AFM images of menthol-encapsulated polymeric nanoparticle suspension (polymer blend : EC, HPMC, PV(OH) A. Sansukcharearnpon et al. / Int J Pharm xxx (2010) xxx–xxx
Multiarm star-block copolymer Multiarm star-block copolymer compared to dendrimer –Less complex synthesis –Less time consuming –Lower cost Limitation –Lower loading capacity than dendrimer
Multiarm star-block copolymer Amphiphilic multiarm star-block copolymers with a hydrophilic inner and hydrophobic outer shell (top) and with a hydrophobic inner and hydrophilic outer shell (bottom). Ternat et al., Macromolecules, Vol. 41, No. 19, 2008 Hydrophilic arms Hydrophobic arms Hyperbranched core structure
Multiarm star-block copolymer Average structures of the Boltorn H40 core and amphiphilic multiarm star-block copolymers H40-(PnBuMA)p-b-(PPEGMA)q and H40- (PCL)p-b-(PAA)q. Ternat et al., Macromolecules, Vol. 41, No. 19, 2008
Comparison of the evaporation rates of benzyl acetate from an aqueous solution (containing 5% of ethanol) in the presence and absence of amphiphilic multiarm star-block copolymer H40-(PCL)24-b-(PAA)82. Multiarm star-block copolymer Benzyl acetate Benzyl acetate/ H40-(PCL)24-b-(PAA)82
Alginate complex capsules containing eucalyptus oil Interfacial insolubilization reaction Release by crashing the capsule between fingers Closed capsule wall Optimum condition –Concentration of alginate –Concentration of calcium salt –Cross-linking time
Microphotographs of alginate complex capsules before (a) and after (b) the hardening process (/80). The capsules were prepared at concentrations of 1.5% sodium alginate and 1.0% calcium chloride, and the cross-linking time of 20 min. C.P. Chang, T. Dobashi / Colloids and Surfaces B: Biointerfaces 32 (2003) 257/262
Time courses of oil release from capsules at incubation process for the samples prepared at various conditions: At different concentrations of sodium alginate at constant calcium chloride concentration of 1 w/v% at cross-linking time of 20 min. The symbols (circle), (triangle), (square) and (diamond) denote concentrations of sodium alginate of 0.25, 0.50, 1.0 and 2.0%, respectively.
Light induced controlled release of fragrances Alkyl phenyl ketones serve as delivery systems for fragrance molecules upon exposure to natural sunlight
Preparation of alginate nanocapsules containing turmeric oil Sodium alginate crosslink with calcium chloride alginate nanocapsule Lertsutthiwong P., Noomun K., Jongaroonngamsang N., Rojsitthisak P., Nimmannit U. 2008. Preparation of alginate nanocapsules containing turmeric oil. Carbohydrate Polymers. 74. 209–214.
Morphology and size of turmeric oil-loaded alginate nanocapsules TEM characterization of nanocapsules, indicating an average size of about 95 nm.