Writing in its European patent, Unilever said its formulation combined the well-known anti-fungal agent piroctone olamine with coconut oil to decrease the level of genus Malassezia species on the human scalp – a yeast that contributed to dandruff. Piroctone olamine was already widely used as a conventional anti-dandruff agent, the company said, but there remained a need to develop formulations that acted fast.
Reduced shower and bath time – faster rinse-off
“The need to lead a sustainable lifestyle; to use less water when showering or bathing, is becoming increasingly important,” Unilever wrote in the patent.
“This means there is a need for products that act quickly, necessitating less time when showering and thus result in less water usage. In addition, products that act quickly are seen as advantageous as they fit in with the consumer’s busy lifestyle.”
Unilever said its formulation could reduce the level of Malassezia species present on the scalp in less than 10 minutes, either in a rinse-off or leave-on format – preferably a rinse-off shampoo. When tested against the efficacy of fungistatic ingredient zinc pyrithione blended in coconut oil, the piroctone olamine-coconut oil blend showed “rapid effectiveness”.
“In the context of the present innovation, rinse-off compositions include shampoos and conditioners, as well as treatment compositions, which can be left on scalp for 0.5 minute to up to 15 minutes, preferably from one minute to ten minutes, more preferably one minute to ten minutes prior to being rinsed off.”
A carefully balanced formula with conditioning agent
Unilever said its blend incorporated 0.1 – 5% of piroctone olamine by weight of the total composition along with a conditioning oil, preferably coconut oil.
“Typically, the most popular conditioning agents used in cosmetic compositions are water-insoluble oily materials such as mineral oils, naturally occurring oils such as triglycerides and silicone oils. Conditioning benefit is achieved by the oily material being deposited onto the skin, resulting in the formation of a film, which makes the skin more lubricant and less dry,” it wrote in the patent.
The coconut oil could be incorporated at a level of 1 – 4 wt% of the final topical composition.
Unilever said the formulation also had to include an anionic cleansing surfactant and cationic deposition polymer, and could optionally include suspending agents, fragrance, dyes, preservatives and natural hair nutrients, such as botanicals, fruit extracts, sugar derivatives and amino acids. Importantly, the pH of the composition had to remain in the range of 5.5 to 6.5.
WIPO European Patent No. EP3695825
Published on: August 19, 2020. Filed on: February 11, 2020.
Title: “Hair care composition”
Inventor: Unilever – LZ. Collins, G. Chen and M. Pu