To apply neutral electrolyzed water, which is closest to the pH of saliva at rest (approximately 7) among electrolyzed water for sterilization, to gels for oral care, we investigated a simple method for preparing gels containing neutral electrolyzed water. Each prototype gel was prepared by mixing and stirring a neutral electrolyzed water (standard: 30 mg/L or high concentration: 140 mg/L) and a thickener/ gelling agent (carboxy vinyl polymer [carbomer], agar, or methylcellulose), and adjusting pH as appropriate. The effectiveness of each prototype gel as a gel for oral care was examined based on its available chlorine concentration and bacteria removal effect, and the operability of the gel preparation was examined based on the time required for the entire preparation process. The available chlorine concentration decreased with the addition of each thickener/ gelling agent in both concentrations of neutral electrolyzed water, with a reduction rate of more than 80% for carbomer, approximately 40% for agar, and approximately 10% for methylcellulose. The gel prepared with carbomer showed a less than 20% bacteria removal rate. On the other hand, the gel prepared with agar or methylcellulose showed a high bacteria removal rate of more than 99.9% even after 24-hour refrigerated storage. The preparation method by adding carbomer required pH adjustment, which took about 30 minutes, and the preparation method by adding agar required heating for solation and cooling for gelation, which took about 25 minutes. On the other hand, the preparation method by adding methylcellulose could be prepared within 1 minute by high-speed stirring. These results suggest that the preparation by adding methylcellulose is effective as a quick and simple method for preparing gels for oral care containing neutral electrolyzed water.
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