Pilling Issue in Hydroxyethyl Cellulose (HEC) Gel Formulation

Pilling that occurs when applying Hydroxyethyl Cellulose (HEC) gel onto the skin is often caused by several factors. The main reasons include:

• Excessive Concentration: If HEC is used at too high a concentration in the formula, the resulting gel might form a film on the skin that is too thick. When this film dries and is rubbed, it can peel off as pilling.
• Incompatibility with Other Ingredients: HEC is a non-ionic polymer and is generally compatible with many ingredients. However, incompatibility issues can arise with certain ingredients, such as some surfactants, high concentrations of salts/electrolytes, or other polymers/film-formers in the same formula. This can lead to subtle precipitation or separation, resulting in pilling upon application.
• Application Over Other Products: Applying the HEC gel over other products that have not fully absorbed or contain ingredients that interact with HEC can also cause aggregation and peeling as pilling.
• Rubbing on the Skin: Rubbing the gel too vigorously or for too long during application can cause the drying HEC film on the skin to frictionally detach and easily peel off as pilling.

To reduce pilling, you might try lowering the concentration of HEC in your formula, check for potential incompatibilities with other ingredients, and adjust the application method by applying gently and allowing it to absorb without excessive rubbing.