Creams, gels and ointments

What are semi-solid dosage forms?

Semi-solid dosage forms are formulations between solid and liquid states, designed for topical or mucosal application, providing localized treatment and ease of application.

What are the advantages of semi-solid dosage forms?

Easy to apply, provide localized treatment, and suitable for skin and mucosal surfaces.

What are the key benefits of oil-in-water creams?

They provide a cooling effect as water evaporates and are ideal for weepy or moist skin conditions.

What makes water-in-oil creams different from oil-in-water creams?

Water-in-oil creams are predominantly oily, offering mild occlusion and better hydration for dry skin conditions.

Why are creams white in appearance?

Micron-sized droplets in the emulsion scatter light uniformly, creating a white appearance.

What are the defining features of ointments?

Ointments are highly viscous, occlusive, and contain less than 20% water and volatiles but more than 50% hydrocarbons, waxes, or polyethylene glycols.

What are the advantages of ointments?

Long-lasting hydration, enhanced drug penetration, and minimal preservatives reduce allergenicity.

What is the primary disadvantage of ointments?

They have a greasy texture, making them less cosmetically appealing.

What is the function of hydrophobic bases in ointments?

They act as occlusive dressings, retaining moisture and protecting wounds, and ensure prolonged drug contact with the skin.

What are gels, and how do they differ from creams and ointments?

Gels are semi-solid solutions or dispersions incorporating gelling agents, forming a clear, non-greasy film.

What makes gels suitable for application in hairy areas?

Their non-greasy texture and ease of removal.

What is a common disadvantage of gels?

They are non-occlusive and may wash off with perspiration.

What role do emulsifiers play in creams?

Emulsifiers stabilize oil and water phases, ensuring uniformity in cream formulations.

What is the main therapeutic use of ointments?

Treating dry, scaly skin and enhancing drug penetration in occlusive conditions.

Name two common methods of ointment preparation.

Trituration (grinding) and melting/blending.

What happens when water-soluble bases absorb water?

They lose their semi-solid consistency if the water content exceeds 10%.