As rheology modifier, NM-Carbomer products are capable of providing high viscosity, excellent thickening and suspending performance not only in personal care products field, but also in toothpastes and other oral care products. Hydrogen peroxide is a disinfectant and is used as a bleaching agent in several tooth-whitening oral care formulations. It is meaningful study to determine the stability of pharmaceutical grade NM-Carbomer gels with various grades of hydrogen peroxide. 

The parameters studied were viscosity, pH, peroxide content, and Brookfield Yield Value, which estimates the ability of a formulation to support a stable suspension. The study for NM-Carbomer 970G, 974P, 10G, 934P was conducted at room temperature and at 45°C, with measurements taken initially and at 1, 3, 6, 9, and 12 weeks. 

Conclusion:  

In hydrogen peroxide formulations, peroxide source and grade are critical factors to consider with regard to carbomer stability.  

 Study results indicate that NM-Carbomer 970G with high crosslink density. would be the better choice if viscosity retention is critical to formulation performance.  NM-Carbomer 10G might be a good alternative if easy processing is critical.  Additionally, if yield value retention is a critical formulation parameter then NM-Carbomer 934P and 974P would be the most suitable choices.

Carbomer crosslink density is also important as highly crosslinked NM-Carbomer best retained their viscosity and yield values.  

Finally, higher peroxide levels may shorten shelf life.