Page 23 - Pharmaceutics-II (02-06-01 203)

Ideal properties of semi-solid dosage forms
• Smooth texture
• Elegant appearance
• Non dehydrating
• Non gritty
• Non greasy and non-staining
• Non hygroscopic
• Easily applicable with efficient drug release

Formulation of semi-solid dosage forms:
1. Base: single or compound, natural or synthetic. According to the nature of the base, the
preparation may be hydrophilic or hydrophobic.
2. Active ingredients: one or more either dissolved or dispersed.
3. Excipients: e.g antimicrobials, fragrances, permeation enhancers,….etc.

Types of semi-solid dosage preparations:
• Ointments
• Creams
• Gels
• Pastes
• Poultices
• Medicated plasters
• Dressing
• Rigid foam

Ointments

What are ointments?

Ointments are semisolid preparations consist of a single-phase base in which solids or liquids
may be dispersed.

Types of ointments

a) Medicated: those with medicaments for treatments of cutaneous (skin diseases). Examples:
Sulfur Ointment, Zinc Oxide Ointment and ophthalmic ointment

b) Non-medicated: also referred to as “ointment bases” used as such for their emollient or
lubricating effect or used as vehicles in medicated ointments. Example: White Ointment

Essential criteria of ointment bases:

• Semi-solid bases do not only act as carriers of the medicaments, but they also control the
extent of absorption of drugs incorporated in them

• An ointment base should be compatible with the skin, stable, smooth, non-irritating, inert,
and capable of releasing the drug incorporated in it readily

22