Polyquaternium-7

Ribeiro, H. M., et al. International journal of cosmetic science, 2004, 26(2), 47-59.

The effects of two synthetic cationic polymers, Polyquaternium-7 and Polyquaternium-11, and a natural anionic polymer, gum arabic, on the rheology and microstructure of creams prepared with a nonionic mixed emulsifier (cetylstearyl-12EO/cetyl alcohol) were investigated.
· Formulation of emulsions
The polymer gels (Polyquaternium-7, Polyquaternium-11, and gum arabic) were initially prepared in water to form gels with the same dry weight of 10% (w/v). This was to ensure that the polymers were pre-hydrated.
Polymer emulsions were prepared according to the following formulation w/w: surfactant (cetyl stearyl alcohol 12mol EO) 3%, (cetyl alcohol) 15%, polymer gel 10%, oily component (decyl oleate) 6%, humectant (propylene glycol) 3%, preservatives (diazolidinyl urea) 0.5% and (methyl dibromoglutaronitrile and phenoxyethanol) 0.2% and up to 100% deionized water. To prepare the emulsions, the oil and water phases were heated to 75 °C separately, then the oil phase was added to the water phase and the system was mixed (130 r.p.m) with constant stirring until 30 °C.
· Effect of cationic surfactants
Cationic polymers interacted with other excipients in the creams, resulting in a significant loss of structure with an increase in droplet size. In continuous shear, the apparent viscosity of the cationic creams was significantly lower than that of the control, while in creep and oscillation, lower elastic and viscous moduli confirmed that these creams were less structured than the control. The DSC data suggest that the cationic polymer does not associate with the nonionic surfactant alone but may reduce the swelling of the lamellar crystalline gel phase, thereby increasing the anhydrous content of the continuous phase.

Nunes, Andreia, et al. Journal of Surfactants and Detergents, 2020, 23(4), 809-819.

In this work, a series of shampoos containing sugar-derived surfactants (i.e., alkyl polyglycosides, decyl glucoside, and coco-glucoside) were formulated with different thickeners and conditioning ingredients to improve the formulation properties, including polyquaternium-7 (formulations 4 and 5). Comparison of formulation efficacy
The efficacy was investigated by in vitro hair combing force assay and in vivo sensory analysis using sodium lauryl sulfate (SLES) formulations as control, and several formulations showed the following characteristics:
(i) Higher pH than SLES (later lowered with lactic acid);
(ii) Stronger foaming than SLES and high wetting;
(iii) Predominantly Newtonian behavior and liquid state with appropriate viscosity;
(iv) Low cytotoxicity to human keratinocytes and retinal cell lines (in contrast to SLES);
(v) Easier combing than SLES when using polyquaternium-7 as a conditioner;
(vi) Effective and mild shampooing;
(vii) Good sensory analysis confirming the previous washing performance.