Writing in four separate international patents [I, II, III, IV], Colgate-Palmolive said the use of certain fatty acid salts ensured stability of single-phase whitening formulas and high-water abrasive compositions, enabling lower levels of calcium salt abrasives in the latter.
Fatty acid salts to stabilise whiteners
Conventional whitening oral care products such as toothpastes, gels and dental trays made with agents like peroxide were often formatted in a two-component system to separate the hydrogen peroxide from potentially reactive components until time of use. However, Colgate-Palmolive said this design was “cost-prohibitive” and often exhibited “decreased mixing efficiency”. What was needed, therefore, was “improved single-phase oral care compositions” with “increased peroxide stability”, the company said in its patent filings.
“Applicants have discovered that utilisation of certain fatty acid salts is effective as a gelling agent for oral care products, particularly for oral care products containing whitening agent,” Colgate-Palmolive wrote.
Use of these fatty acid salts in single-phase whitening formulas “surprisingly and unexpectedly” increased the stability of agents like peroxide, the company said.
In its three separate patents, the company outlined different blends of fatty acid salts that could be used in single-phase whitening oral care formulas. The fatty acids could be saturated or unsaturated, it said, and the salts selected from sodium, potassium, lithium salts or stearates.
The formulas, Colgate-Palmolive said, were able to stabilise hydrogen peroxide included at 1-50 wt%, preferably less than 10 wt%, and support abrasive components up to 15 wt%. The pH of the formulas could also be controlled to sit between 6.0 and 9.0 pH.
Importantly, the method enabled the creation of oral care compositions “free, or substantially free, of fatty alcohols” and the peroxide stability was achieved “without encapsulations and/or film-type materials”, it said.
Colgate-Palmolive said the composition could be used to develop a range of finished oral care whitening products, including toothpaste, tooth polish, tooth gel, chewing gum, lozenges, mouthwash, whitening strips, tooth varnish and even dental trays comprising a gel or paste.
Fatty acid salts to reduce abrasive components
In its fourth patent, Colgate-Palmolive outlined how fatty acid salts could also be used to reduce the levels of abrasive components in high-water oral care formulas, in turn also improving stability of the finished product.
“It is difficult to stabilise high-water toothpaste containing less than 30% precipitated calcium carbonate (PCC) or natural calcium carbonate (NCC) abrasive,” the company wrote. “It would therefore be desirable to provide an oral care composition which comprises a lower levels of calcium salt abrasive, but which also maintains the stability and beneficial physical attributes of higher calcium salt containing compositions.”
The suggested formula, Colgate-Palmolive said, enabled calcium carbonate abrasives to be incorporated at less than 30%
Patent I: WIPO International Patent No. WO/2022/051209
Published on: March 10, 2022. Filed on: August 30, 2021.
Title: “Oral care compositions”
Inventors: Colgate-Palmolive – G. Pan, L. Fei and S. Chopra
Patent II: WIPO International Patent No. WO/2022/051221
Published on: March 10, 2022. Filed on: August 30, 2021.
Title: “Oral care compositions”
Inventors: Colgate-Palmolive – G. Pan, L. Fei and S. Chopra
Patent III: WIPO International Patent No. WO/2022/051214
Published on: March 10, 2022. Filed on: August 30, 2021.
Title: “Oral care compositions”
Inventors: Colgate-Palmolive – G. Pan, L. Fei and S. Chopra
Patent IV: WIPO International Patent No. WO/2022/051227
Published on: March 10, 2022. Filed on: August 30, 2021.
Title: “Oral care compositions”
Inventors: Colgate-Palmolive – G. Pan, L. Fei, S. Chopra and P. Kulkarni