Creams and Lotions

What is a semisolid dosage form?

A viscous preparation that is not pourable/does not flow under low shear stress at room temp, but does spread on skin

Uses of semisolid dosage forms?

Protect skin/mucous membrane from chemical/physical irritants

Promote hydration of the skin, emollient

Provide a vehicle for medication

Characteristics of an ideal cream?

Non irritating

Non allergenic

Non staining

Able to be accurately dosed

Easy to apply

Doesn’t support bacterial/fungal growth

What are creams?

Semisolid dosage form

More than 20% water/volatiles

Less than 50% hydrocarbons, waxes, or polyols

For external application, can be w/o or o/w

What are oil in water emulsion bases?

Water washable/water removable bases

Can be applied on moist skin lesions

Form a semipermeable film at site of application upon evaporation of water

Examples of o/w bases

Dermabase, Cetaphil, Aquaphilic

What are the emulsifying aids used in o/w creams?

Beeswax, sterols, fatty acids, wool alcohols, wool fats, lanolin

What properties do o/w cream emulsifiers have?

Good emollient

Creamy white/translucent creams

High viscosity

What kind of emulsifiers are used in w/o creams?

Synthetic waxes, cetostearyl alcohol, cetyl/stearyl alcohols

What properties do w/o cream emulsifiers have?

Rapid absorption

Lower viscosity

How do you test for quality for topical semisolids?

Presence of particles/grittiness

pH

Viscosity

Physical stability