Effect of Fragrances on Perfume Emulsion Stability Matt Vanden Eynden, Ph.D. Formulaction, Inc.
Presentation Outline • Fragrances, once introduced into cosmetic and personal care applications, can occasionally impact the cohesion and stability of end-products and lead to instabilities. • The disruption of the emulsion or the movement kinetics of the fragrance component can cause visual phase separation, redispersibility issues and performance issues that render the material unlike the unaged version. It is essential to provide stable products to avoid customer dissatisfaction. • While visual shelf life analysis is a direct method for investigation it can become time consuming and can also be a subjective measurement. • Therefore, it is of interest to the formulator to design a test or have access to data that will quantify these destabilizations.
Presentation Outline • A group at Givaudan (Switzerland) provided stability data on some perfume and fabric care emulsions, demonstrating the stability of the materials and how they are analyzed inside of their labs. • Monitoring is done in less than a day to provide quantitative stability results for these emulsions.
Turbiscan: Instrument Technology and Theory • Turbiscan technology (Formulaction, FR) utilizes an 880 nm light source and a moving reading head to analyze the static light scattering data at all points in transparent (transmission) and opaque (backscatter) samples. • By detecting the light intensities at every 40 µm of sample height, a resolved picture of the particle migration and particle size change can be quantitatively determined. • Samples as high as 95% volume fraction of particles can be analyzed, allowing materials to remain in their native state for analysis.
Turbiscan: Instrument Technology and Theory Backscattering and transmission signals are Repetition of the measurement provides: dependent upon two factors: Δ d : change in particle size d : particle size Δ Φ : change in particle concentration Φ : particle concentration Scans are made over the entire sample height and over time: Signal variation ➠ Variation in the sample ➠ Monitoring of stability
Data analysis Sedimentation and Creaming Sedimentation Top of vial: signal decrease (clarification) Bottom of vial: signal increase (sediment) Creaming Top of vial: signal increase (creaming) Bottom of vial: signal decrease (clarification)
Data Analysis Destabilization Kinetics Sedimentation Layer Quantification Phase separation thickness (bottom of sample) A A B B Concentration variation (bottom of sample) A Sample A particle migration B Higher sedimentation thickness Higher phase concentration
Data Analysis Flocculation and Coalescence Size change Entire sample: signal decrease/increase
Data Analysis Multiple Destabilization Events Flocculation 2 nd 1 st 2 nd Creaming Complete understanding of the destabilization and kinetic of each phenomena
Data Analysis Turbiscan Stability Index (TSI) One-click Stability Criteria : T urbiscan S tability I ndex Less stable Sample TSI Name (8 days) Test 1 4.1 Test 2 1.5 Ref 1.1 Test 3 0.6 More stable One-click parameter No additional information required Takes in account ALL DESTABILIZATIONS One unique number to rank & compare samples
Publications using the 300 250 Number of publications 200 150 100 50 0 2010 2011 2012 2013 2014 2015 2016 2017
Data Analysis Mean Particle Size Calculations Type of sample Particle Particle Refractive index TiO 2 I (I) SiO 2 H Polystyrene K ZnO G TiO 2 S-MLS CaCO 3 F (C) (@ 0.001%) DLS SiO 2 Suspension E (G) Talc D TiO 2 C (K) (B) (F) (H) Al 2 O 3 B ZnO (L) (J) Ludox (colloidal silica) A (N) (E) (13 nm) (A) (D) (P) Polystyrene J (O) (M) Bovine Serum Albumin Protein L Mean diameter (µm) Emulsion with sunflower oil P (surfactant tween 20) Concentration (%v/v) (Q) Emulsion N Emulsions Emulsion with sunflower oil O (surfactant sodium caseinate) Hair foam Healthcare emulsion M (155 µm @ 60%) Hair foam Foam Q SMLS covers a wider concentration area than DLS (17% of samples)
Stability Applications Home & Personal Care
Stability Applications Perfume Stability: Experiment Design • A standard perfumed base is tested for stability by incorporating three different fragrances at varying dosages. Quick analysis to optimize each formulation. • Each fragrance is currently on the market in a standard emulsion formulation. Here, the same fragrances will be tested in a new emulsion to track the stability of the new formula. Controls stability from formula to formula – match, mimic, and predict shelf life. • The experiment is performed for 2 hours at 45 º C, scanning once per minute. This allows full destabilization profiles to be seen by the Turbiscan while no visual phase separation is seen by the naked eye. Extensive shelf life studies are not required (days, weeks, months). • After the analysis, global stability (TSI) is tracked to quickly analyze the formulations as acceptable or non-acceptable. One-click analysis to understand the impact of destabilization kinetics. • If needed, individual kinetics can be analyzed for a more in-depth understanding of the phenomena. Detailed information about each formulation as it ages.
Stability Applications Perfume Stability: Results • Data can be split into three regions in the bottom, middle, and top of the sample in order to show specific destabilization phenomena. Bottom of sample: decrease in BS signal – particles migrating away from this region Middle of sample: global change in BS signal = particle size increase Top of sample: local decrease in BS signal – oil layer formation + coalescence
Stability Applications Perfume Stability: Results • Utilizing the TSI function, all destabilization phenomena are derived into a single number and the kinetics of this global function are plotted for each variable. • Dosed at 1% and 1.75%, the lower amount of fragrance A is similar to the un-perfumed formulation, signifying a similar stability for the two emulsions.
Stability Applications Perfume Stability: Results • Fragrance B shows a much better overall stability (TSI = 1.6 and 1.2) than that of fragrance A (TSI = 1.1 and 4.4). • In fact, dosing at 1.75% shows better destabilization kinetics than when the emulsion is dosed at 1%.
Stability Applications Perfume Stability: Results • Interestingly, a 1% dosing of fragrance C increased the stability of the formulation when compared to the un-fragranced emulsion. Dosing at 1.75% showed a clear decrease in stability.
Stability Applications Perfume Stability: Results • Graphing the TSI values at the end of the experiment gives a better display as to the effect of the formulation differences. • Internally, this customer set a stability threshold of TSI = 2. Everything above that is considered a “fail” and will not be optimized further, in favor of the alternate formulations. Stable sample This 2-hour experiment provides quantitative stability data and fast formulation optimization.
Stability Applications Detergent Stability • A “heavy duty” liquid fabric detergent is monitored in order to optimize the perfume identity in the emulsion for maximum stability. • The experiment is performed at 45 º C for 7 hours . • In a similar manner as before, full destabilization profiles are captured and then analyzed with the TSI in order to optimize the formulation without excessive visual shelf life studies.
Stability Applications Detergent Stability: Results • Data can be split into three regions in the bottom, middle, and top of the sample in order to show specific destabilization phenomena. Bottom of sample: decrease in BS signal – particles migrating away from this region Middle of sample: no change = no flocculation or coalescence events Top of sample: local increase in BS signal – creaming of oil layer
Stability Applications Detergent Stability: Results • The large TSI observed in only a few hours of the original perfume provides an unstable, phase- separated emulsion. • Modification to an alternate perfume provides a much greater enhancement to stability. The best additive is quickly identified and can be further optimized
Stability Applications Fabric Softener Stability • A fabric softener formulation was deemed unstable, but contains many components. • Each component was tested individually and the culprit was the encapsulated perfume that was used. • Knowing this, the formulation can be modified to further enhance stability. Differences are seen after 1 hour = significant time savings
Thank you! Visit us at booth #223 matt@formulactionusa.com Formulaction.com
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