Final Formulation Stability: The Effect of Ingredient Quality

In this week’s blog post, we look at the quality control of raw materials in the cosmetics industry, and how the Turbiscan Classic can be used to assess this.

Formulation development is a vital activity for many industries, including pharmaceuticals, paints, and coatings. As sales of formulated products amount to approximately £180 billion per year in the UK, getting formulations “right” is a crucial and valuable goal.

Stability is a crucial attribute for many products with a direct impact on performance, shelf-life, kerb appeal and ultimately, worth. A systematic approach to understanding and developing stability can therefore be extremely helpful in improving the likelihood of success in long term stability trials, and accelerating formulation. Part of this process depends on the quality of the ingredients.

This is because the nature and the quality of a constituent in a formulation may influence its stability. As a formulator, you need to test the stability of your emulsions, suspensions, and foams with different types of raw materials. When dealing with natural products, the difference in quality can be more noticeable when moving from one supplier to another.

To examine this, the effect on the stability of two cosmetic emulsions via the introduction of Jojoba oil from different suppliers was analysed using the Turbiscan Classic.

How was the study carried out?

Two kinds of emulsion, a Sport lotion and a Sensitive lotion were prepared with Jojoba oil from different suppliers:

• with oil noted 1
• with oil noted 2
Samples number: 4
Analysis volume: 6 ml
Temperature of analysis: 43°C
Analysis Duration: 24 hours

Two hours were needed to bring the samples to the required temperature (43°C). The curve after 2 hours of analysis was selected as a reference. The subsequent traces show the changes in back scattered light intensity (%, y-axis) on the tube height (mm, x-axis) as a function of time (the last curve is always displayed in red).

What were the results of the study?

The profiles obtained show different kinds of backscattering change:

• NO significant backscatter change at the top of the samples prepared with oil 1, characteristic of no change in this zone (please see Figure 1 below).

• a backscattering decrease at the top of the samples prepared with oil 2, characteristic of a clarification of the samples in this zone (please see Figure 2 below).

The calculation of the slope of the graph over 12 hours allows the calculation of the destabilisation speed as a function of the Jojoba oil type used (Figure 4).

The jojoba oil 1 used in both formulations made more stable emulsions than Jojoba oil 2. This quality difference can be explained by the different oil extraction methods employed by the different suppliers.

In conclusion, the Turbiscan range can detect particle migration phenomena in a few hours and allows for a quantitative comparison of the results to be made for each sample. It is, therefore, a useful tool for those formulators looking to study the effect of raw material variation on their samples.

For more information about the Turbiscan and how it can help your own formulations, please email: sales@fullbrook.com or call: 01442 876777.