Formulation with Urea and Gluconolactone

Thank you for your question regarding the formulation of Urea with Gluconolactone. It's correct that using Gluconolactone at approximately 15% of the Urea concentration is recommended for stabilization.

Regarding your questions:

1. Reducing Gluconolactone Percentage:
   The recommendation to use Gluconolactone at about 15% of the Urea amount is primarily for stabilizing the Urea and preventing its pH from rising over time, especially in warmer conditions or for products requiring a long shelf life. Reducing the percentage of Gluconolactone below this recommended ratio may compromise the long-term stability of the Urea and its ability to effectively counteract the pH increase. While reducing it would likely raise the initial pH, it might negatively affect the stability benefit.

2. Adjusting pH with a Base:
   Yes, if using the recommended ratio of Urea and Gluconolactone results in a pH that is lower than your target range of 4-5.5 (as you observed with a pH below 3), you can and should use a suitable base (alkaline ingredient) to adjust the pH upwards to your desired range. This is a standard procedure in cosmetic formulation to achieve the optimal pH for the final product. Common bases used for this purpose include Sodium Hydroxide or Triethanolamine.

By using the recommended ratio of Gluconolactone for stabilization and then adjusting the final pH with a base, you can achieve both the desired stability and the target pH range for your formulation.