Gel Formation Issue in Sunscreen Formula

Your formula contains oil-soluble UV filters (OMC, Octocrylene, Octisalate) and Isododecane, along with Hectorite. Hectorite is an oil-thickening clay, and while it helps increase viscosity, a high concentration like 10% might still not be sufficient to form a stable gel depending on the specific type of Hectorite and the overall composition of the oil phase.

To achieve a gel texture in this type of oil-based or anhydrous system, you need an effective oil gelling agent. Ethylcellulose is a suitable option for gelling oil phases.

Ethylcellulose acts as an oil thickener and film former. Different grades of Ethylcellulose are available, offering varying levels of viscosity. You would typically disperse Ethylcellulose in the oil phase and heat it to around 70-85°C until it dissolves clearly. Upon cooling, the mixture will thicken and form a gel.

You can experiment with different grades and concentrations of Ethylcellulose to achieve the desired gel consistency for your sunscreen formulation.