Things worth knowing about "Unguentum emulsificans aquosum"
Unguentum emulsificans aquosum is a water-containing, emollient base ointment used in pharmacy as a moisturizing skin care product and as a vehicle for individualized topical preparations.
What is Unguentum emulsificans aquosum?
Unguentum emulsificans aquosum (Latin for “aqueous emulsifying ointment”) is a standardized base ointment described in the German Pharmacopoeia (Deutsches Arzneibuch, DAB). It belongs to the group of hydrophilic ointment bases and is used both as a standalone skin care product and as a vehicle for compounding individual topical medications in the pharmacy.
The ointment is white to off-white, has a soft, cream-like consistency, and spreads easily on the skin. Due to its composition, it intensively moisturizes and nourishes the skin, protects against moisture loss, and supports the natural skin barrier.
Composition
According to the German Pharmacopoeia (DAB), Unguentum emulsificans aquosum consists of the following ingredients:
- Emulsifying cetostearyl alcohol (Lanette N): A mixture of cetyl alcohol, stearyl alcohol, and sodium lauryl sulfate that acts as an emulsifier, binding the water and oil phases together.
- White soft paraffin (Vaseline): A hydrocarbon gel that provides an occlusive layer on the skin, reducing water evaporation.
- Liquid paraffin (mineral oil): An additional hydrocarbon oil that adds emollient properties and enhances the smoothness of the ointment.
- Purified water (Aqua purificata): Forms the aqueous phase of the emulsion and provides direct hydration to the skin.
Mechanism of Action and Pharmacological Properties
Unguentum emulsificans aquosum is an O/W emulsion (oil-in-water emulsion) in which the oily and aqueous phases are stably combined by the emulsifier. The key mechanisms of action include:
- Occlusion: The lipophilic components (white soft paraffin, liquid paraffin) form a thin film over the skin surface, reducing transepidermal water loss (TEWL).
- Hydration: The high water content directly moisturizes the upper layers of the skin, making it softer and more supple.
- Emolliency: The fat components replenish lipids lost from dry or damaged skin.
- Emulsification: The cetostearyl alcohol ensures a stable, homogeneous consistency and allows the uniform distribution of active ingredients in compounded preparations.
Indications and Areas of Use
Unguentum emulsificans aquosum is used in various clinical and cosmetic contexts:
- Basic therapy for dry skin (xerosis cutis): Intensive care and moisture supply for very dry, cracked, or scaling skin.
- Supportive care in dermatological conditions: For example, in atopic dermatitis (eczema), psoriasis, ichthyosis, or other chronic skin conditions as part of an emollient therapy regimen.
- Compounding base in pharmacy: As a vehicle for incorporating active substances such as corticosteroids, urea, or antibiotics into individually tailored topical preparations.
- Skin protection: Prevention of skin damage caused by external factors such as cold, dryness, or irritation.
Application and Dosage
The ointment is typically applied once or twice daily in a thin layer to the affected skin areas and gently massaged in. Particularly effective application occurs directly after bathing or showering while the skin is still slightly moist, helping to lock in moisture. The exact dosage and frequency depend on the individual skin condition and medical recommendation.
Tolerability and Side Effects
Unguentum emulsificans aquosum is generally considered well tolerated. In rare cases, the following reactions may occur:
- Contact allergies: Particularly to sodium lauryl sulfate (a surfactant contained in the emulsifier), which may cause irritation or allergic reactions in sensitive skin.
- Comedogenicity: When applied to the face, the occlusive nature of the ointment may promote blackheads in individuals with oily or acne-prone skin.
- Skin irritation: In the presence of severely inflamed or weeping skin (e.g., open wounds, exudative eczema), use should be discussed with a physician or pharmacist.
Storage
The ointment should be stored at room temperature (15–25 °C), protected from light. The container should always be tightly closed after use to prevent contamination or drying out.
References
- Deutsches Arzneibuch (DAB) 2023 – Monograph: Unguentum emulsificans aquosum. Deutscher Apotheker Verlag, Stuttgart.
- European Pharmacopoeia (Ph. Eur.) 11th Edition – Emulsifying Ointment. Council of Europe, Strasbourg, 2023.
- Schauder S, Schauder C – Dermatological Compounding Formulas and Ointment Bases. Springer Medizin Verlag, Berlin, 2020.