Adding Ketoconazole to Shampoo

Ketoconazole is a pharmaceutical active ingredient commonly used in medicated shampoos for treating fungal infections like dandruff. Adding it directly to a pre-made shampoo base requires careful consideration and is generally not recommended for home formulators without proper knowledge of stability, compatibility, and efficacy.

Commercial ketoconazole shampoos are specifically formulated to ensure the ingredient remains stable, evenly dispersed, and effective, while also being safe and pleasant to use. Simply mixing ketoconazole powder or a different form into an existing shampoo base may lead to issues such as:

• Stability problems: The ketoconazole might degrade over time.
• Solubility/Dispersion issues: It might not dissolve or disperse evenly, leading to reduced efficacy or sedimentation.
• Compatibility issues: It could react with other ingredients in the shampoo base.
• Efficacy concerns: The final product might not deliver the intended therapeutic effect.
• Safety concerns: Incorrect concentration or dispersion could lead to skin irritation or other adverse effects.

For these reasons, it is best to use commercially available ketoconazole shampoos or consult with a professional formulator if you intend to create a custom product.

Calculating 2% by Weight

If you were to add an ingredient at a concentration of 2% by weight to a formulation, the calculation is based on the total weight of the final product. The formula is:

(Weight of Ingredient / Total Weight of Formulation) * 100% = Percentage Concentration

To find the weight of the ingredient needed for a desired total weight of formulation at a specific percentage:

Weight of Ingredient = (Desired Percentage / 100) * Total Weight of Formulation

Example: To make 100 grams of shampoo containing 2% ketoconazole:

Weight of Ketoconazole = (2 / 100) * 100 grams = 2 grams

So, you would need 2 grams of ketoconazole and 98 grams of the shampoo base (or other ingredients) to make a total of 100 grams of product with 2% ketoconazole by weight. You would need an accurate scale to weigh both the ingredient and the base.

However, as mentioned, simply mixing may not result in a stable or effective product.