• Approved natural by Ecocert
• Solubilises a wide range of lipophilic ingredients
• Cold processable and easy to handle
• Ultimately biodegradable
• Does not adversely affect foaming of detergent systems
• Counter-irritant

NatraGem S140 has been designed to be used as an easy to handle, cold mix solubiliser. It can be incorporated into a formulation in three different ways:

• NatraGem S140 and the oil are premixed and added to the water phase with moderate stirring.
• NatraGem S140 and the oil are premixed, and then the water phase is added to the premix with moderate stirring.
• NatraGem S140 and the oil are premixed, and then twice the quantity of water is added and stirred to give a free flowing solution. This can then be added to the water phase with a minimal amount of stirring. This option is particularly useful if the final formulation has a tendency to foam.

Generally, NatraGem S140 will give clearer solutions over time, so formulations may take up to 24 hours to reach full clarity.

NatraGem S140 is an easy to handle liquid that can be used in cold process systems with efficient solubiliser to oil ratios. To demonstrate this, the solubilisation effectiveness of NatraGem S140 has been compared to two commonly used solubilisers, Polysorbate 20 and PEG-40 Hydrogenated Castor Oil. Polysorbate 20 is a cold process solubiliser that is similar to NatraGem S140 in terms of ease of use, whereas PEG-40 Hydrogenated Castor Oil, which is considered a highly efficient solubiliser, requires heating (~50°C) before use and can produce a surfactant gel on mixing with water. The gel needs further heating and stirring to ensure dissolution.

The solubilisers were tested with a wide range of lipophilic substances, including fragrances and essential oils. The base formulation used is shown below:

Lipophilic ingredient: 1%

Solubiliser: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20%
[NatraGem S140 or Polysorbate 20 or PEG-40 Hydrogenated Castor Oil]

Deionised water: upto 100%

The study involved altering the surfactant to oil ratio, until the lowest ratio that produced a clear solution after 24 hours was found. The surfactant to oil ratios evaluated were: 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 12:1, 15:1 and 20:1. For oils that could not be solubilised at 20:1, the result is listed as >20:1 and no further ratios were evaluated.

Pre-experimental information:

• The experiments involving NatraGem S140 and Polysorbate 20 were performed at room temperature.
• PEG-40 Hydrogenated Castor Oil was heated to 60°C when mixed with the water, further heating and rapid mixing was used up to 70°C to ensure that the surfactant gel formed had dissolved into the solution.
• Polysorbate 20 and PEG-40 Hydrogenated Castor Oil are both 100% active. NatraGem S140 is 80% active, so the surfactant to oil ratio is also shown as 100% active for a fair comparison.

Impact on Foaming

The impact on foaming of NatraGem S140 was investigated using the bath and shower base formulation (HC/HS/25), with and without 1g/L NatraGem S140 and fragrance in three different water hardness levels. The Ross Miles test was used, with foam height in mm being measured initially and after 5 minutes.

The results in Figure 1 show that NatraGem S140 can boost and stabilise foaming. The effect and its extent is dependant on the system and the level of NatraGem S140 required.

Figure 1: Ross Miles foam height comparisons of a detergent with and without the NatraGem S140 and fragrance

Counter-Irritancy Properties

NatraGem S140 has been proven to mitigate the irritancy effects of 1% sodium lauryl sulphate (SLS) in water, when patch tested on human skin. In order to demonstrate this excellent counter-irritancy effect, a study was carried out on 12 volunteers to measure Trans-Epidermal Water Loss (TEWL) and skin inflammation. Testing was carried out on the forearm of panellists, in a temperature and humidity controlled environment.

The products tested were:

• Water (used as a control)
• 1% SLS in water (w/w)
• 1% SLS + 1% NatraGem S140 in water (w/w)
• 1% SLS + 5% NatraGem S140 in water (w/w)
• Neat NatraGem S140

Basal TEWL and inflammation (using a Laser Doppler) readings were taken, and then equal amounts of each product were applied to filter paper before being applied to the skin and occluded for 24 hours. The patches were removed one hour prior to the TEWL and inflammation readings being taken again. All test sites were randomised.

The results of the TEWL readings are shown in Figure 2 and clearly illustrates that the SLS significantly disrupts the skin barrier, leading to an increase in water loss through the skin. The addition of 1% NatraGem S140 to 1% SLS significantly reduces this water loss, whilst the addition of 5% NatraGem S140 to 1% SLS lowers the water loss to show equivalence to that of water alone. Neat NatraGem S140 is shown to have no effect on water loss through the skin.

Figure 2: TEWL results of human patch testing to show counter-irritancy effects of NatraGem S140 with SLS

(***)1: significance vs. water p<0.001
(***)2: significance vs. SLS p<0.001
n.s: not significant vs. water

The results of the inflammation readings are shown in Figure 3, which demonstrates that 1% SLS significantly increases inflammation compared to the water control. There is, however, no significant increase in inflammation when 1 and 5% NatraGem S140 was added to 1% SLS. Neat NatraGem S140 also had no effect on the skin inflammation.

Figure 3: Inflammation results of human patch testing to show counter-irritancy effects of NatraGem S140 with SLS and correlating images

(***)1: significance vs. water p<0.001
n.s: not significant vs. water

Photos below in Figure 4 are taken from the human patch test study to show how the counter-irritancy benefits of NatraGem S140 with SLS can also be seen by human eye.

Figure 4: Photos from the human patch study to visually show the counter-irritancy benefits of NatraGem S140 with SLS