Topic overview

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Creams are emulsions that spread readily, while ointments are viscous, single-phase preparations that tend to be more occlusive. Gels use polymer networks to trap liquid and can provide a clear, cooling preparation; pastes are thicker ointments with a high solid content that helps them remain in place. These differences matter when matching a formulation to a site or skin condition. The lesson also connects base selection with washability, drug release, and preservative needs, and introduces quality checks such as rheology, pH, and in-vitro release. This preview outlines the key distinctions; the full lesson develops their formulation and practical implications.