Selenium sulfide is an antifungal agent commonly used in shampoos to treat various scalp conditions. Here are some key points about its use in shampoos:

Uses:

1. Dandruff: Selenium sulfide helps reduce the flaking, itching, and irritation associated with dandruff.
2. Seborrheic Dermatitis: It is effective in managing this inflammatory condition that causes scaly patches and red skin, primarily on the scalp.
3. Tinea Versicolor: It can be used to treat this fungal infection that causes small, discolored patches on the skin.

How It Works:

Selenium sulfide works by slowing down the growth of the fungus that causes these conditions. It also helps to reduce the turnover of skin cells, which can alleviate scaling and itching.

Application:

• Shampoo: Usually, selenium sulfide shampoos are used twice a week for the first two weeks, then reduced to once a week or as directed by a healthcare provider. The shampoo should be massaged into the scalp and left on for a few minutes before rinsing thoroughly.
• Precautions: Avoid contact with the eyes, mouth, and broken skin. If accidental contact occurs, rinse thoroughly with water. It should not be used on inflamed or broken skin.

Concentrations:

1. 1% Selenium Sulfide:
   • Commonly found in over-the-counter dandruff shampoos.
   • Suitable for mild to moderate dandruff and scalp conditions.
2. 2.5% Selenium Sulfide (can only be used in drug, not allowed in cosmetics):
   • Often available by prescription.
   • Used for more severe cases of dandruff, seborrheic dermatitis, and tinea versicolor.

Usage Guidelines:

• 1% Shampoo: Typically used twice a week for the first two weeks, then reduced to once a week or as directed by a healthcare provider.
• 2.5% Shampoo (can only be used in drug, not allowed in cosmetics): Usage frequency should be directed by a healthcare provider, usually starting with twice a week and adjusting based on response and improvement.

Formulation Guideline:

1. Dispersion – Pre slurry the powder in ~5 % of the primary anionic surfactant under high shear until uniform.

2. Suspension control – Use 1 – 2 % magnesium aluminium silicate, hydroxypropyl methylcellulose or xanthan to prevent sedimentation.

3. pH window – Maintain final pH 4.5 – 6.0 (critical to stay < 6.5; degradation occurs above this range) Google Patents.

4. Surfactant system – Ammonium/TEA laureth sulfates + cocamidopropyl betaine give good foaming and compatibility.

5. Order of addition – Add fragrance and dyes only after the suspension is cooled below 40 °C to avoid agglomeration.

6. Viscosity adjustment – Sodium chloride or PEG 150 distearate can be used, but check settling after 4 week storage at 40 °C.

7. Chelates / oxidisers – Avoid EDTA Fe complexes and strong oxidisers; they can darken the slurry.

Use: used in medicate shampoo formulation.

How to mix: final mix The temperature of cosmetics must be below 40 °C

Utilization rate: 1% (FDA allows maximum 1% to be used in cosmetics, above this level the product must be registered as drug)

Product characteristics: orange/red/brown powder

Dissolution : insoluble in water

Storage: For long-term storage store at room temperature Avoid heat, humidity and sunlight. At least 24 months of shelf life.

INCI Name : Selenium sulfide