HYGIENE
Skin moisturisation was inferred from measuring transepidermal water loss using a Tewameter TM 300, following the same clinical protocol as described previously. This is an indispensable parameter for the evaluation of the water barrier function of the skin. Even the slightest damage in the skin water
barrier can be determined at an early stage. The deterioration in hand skin condition is often observed as hand sanitisers are used, due to the drying effect of ethanol. The results of this test are shown in Figure
2. The reduction in water loss is represented in the diagram, therefore a higher result means a better skin moisturisation. At all time points, both test formulas show
a better result than the control, untreated skin. However, the improvement on skin moisturisation is statistically significantly higher for the formula containing HPC than the one containing carbomer. Although technical measures give non-
subjective results, the consumer experience is the determining factor for acceptance of personal care products. A sensory evaluation was conducted to compare key tactile attributes. The results are shown in Figure 3 in the shape of a spider chart. The higher the score (from 0 to 5), the more preferred by the panellists. The low pH hand sanitiser formulation
listed in Table 3 was compared to a carbomer containing one. The scores on all attributes were similar or significantly superior to the placebo. The absolute score was high for the HPC containing formulation on spreadability, glide/slip, ability to rest on skin and moisture feel.
Conclusion Alcohol-based hand sanitisers often cause dryness and an unpleasant hand feel, resulting in lower consumer acceptance. The problem is exacerbated with a higher alcohol content. Therefore, it is important to incorporate
ingredients in the formula that offer added benefits of moisturisation and improved skin sensory properties, without compromising on performance of the formula. Hand sanitiser formulas containing up to 70% ethanol in addition to an organic acid have proven to be effective against both enveloped and non-enveloped viruses, resulting in full virucidal activity. Formulations are thickened with cellulose-
derived polymers as these molecules are compatible with weak acid, have a wide pH and electrolyte tolerance and can thicken high levels of alcohol (up to 100% for Klucel). Therefore, cellulose-derived rheology modifiers can improve the sustainability profile of the product while improving the moisturisation and skin feel.
■ T30min ■ T60min ■ T90min
50 45 40 35 30 25 20 15 10 5 0
**** 45%
**** 40%
**** 40%
77
7% 1% Untreated
5%
5%
4%
2%
Carbomer formula #M200-1294D
Low pH formula #M200-1330
NS: Not significant, p<0.1 Δ: Directional 0.05<p<0.1 *: Significant, p<0.05
**: Very Significant, p<0.01 ***: Highly Significant, p<0.005 ****: Extremely Significant, p<0.0001
Figure 1: Improvement in skin hydration, quoted as a percentage for untreated skin or treated with formulas from Table 2 and Table 3. The measurement was performed using a Corneometer CM825 that determines the hydration level of the skin surface (stratum corneum) by measuring the change in the dielectric constant due to skin surface hydration changing the capacitance of a precision capacitor. Results were statistically analysed following a paired t-test methodology
■ T30min ■ T60min ■ T90min
30 25 20 15 10 5 0
23% ***
*** 19%
12% 10% 4% 2% Untreated 1%
Carbomer formula #M200-1294D
Low pH formula #M200-1330
NS: Not significant, p<0.1 Δ: Directional 0.05<p<0.1 *: Significant, p<0.05
**: Very Significant, p<0.01 ***: Highly Significant, p<0.005 ****: Extremely Significant, p<0.0001
Figure 2: Reduction in transepidermal water loss (TEWL), quoted as a percentage for untreated skin or treated with formulas from Table 2 and Table 3. The Tewameter TM 300 measures the density gradient of the water evaporation from the skin which is then reported as TEWL. Results were statistically analysed following a paired t-test methodology
■ Hand sanitiser with Klucel™ H CS HPC @ low pH ■ Carbomer formula
Spreadability *** Non-tacky Δ
5.0 4.0 3.0 2.0 1.0 0.0
11% 22% ***
Ability to rest on skin ****
PC
References 1. Kramer et al. Journal of Hospital Infection. 2006, 62, 98–106
2. Sato et al. Nature Scientific Reports. 2020, 10:15878
3. Kampf G. Journal of Hospital Infection. 2018, 98
www.personalcaremagazine.com Moisture feel **
Clean feel Δ
Glide & Slip ****
NS: Not significant, p<0.1 Δ: Directional 0.05<p<0.1 *: Significant, p<0.05
**: Very Significant, p<0.01 ***: Highly Significant, p<0.005 ****: Extremely Significant, p<0.0001
Figure 3: Sensory evaluation comparing a hand sanitiser formulation thickened with HPC and one thickened with carbomer. The higher the score the more preferred by the panellists
October 2022 PERSONAL CARE
Reduction in TEWL
% Improvement in Skin Hydration
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108
