Semisolids Flashcards
Ointments
- Semisolid preparations intended for external application to the skin or mucous membranes
- Medicated or non-medicated
- Used for physical effects - protectants, emollients, lubricants
Ointment Bases (4)
- Oleaginous (hydrocarbons)
- Absorption bases
- Water removable bases
- Water soluble bases
More hydrophilic as you go down
Oleaginous Bases
-Emollient effect on skin (occlusive)
-Reside on skin for prolonged periods
-Difficult to wash off
-Small amounts of water and aqueous preparations can be incorporated with difficulty
-Solids can be incorporated with levigation
EX: Petrolatum, White Petrolatum, Yellow & White Ointment
Absorption Bases
-Those that permit the incorporation of aqueous solutions resulting in W/O emulsions
-W/O Emulsions permit additional quantities of aqueous solutions
-Not as occlusive as oleaginous bases, semi-occlusive, not easily removed with water
EX: Hydrophilic Petrolatum, Lanolin
Water Removable Bases
-O/W Emulsions resemble creams
-Easily washed from skin
-Able to be diluted with water or aqueous solutions
-Can absorb serous discharge
EX: Hydrophilic ointment
Water Soluble Bases
-No oleaginous components
-Completed water-washable (greaseless)
-Does not incorporate water or aqueous solutions well (softens)
-Cetyl or steryl alcohol is added to increase firmness
-Mostly used for incorporation of solids
EX: Polyethylene Glycol Ointment
Selection of Appropriate Bases Considerations (7)
- Desired release rate
- Topical or percutaneous absorption
- Degree of occlusion of moisture from the skin
- Stability of drug in base
- Effect, if any, of drug on consistency of base
- Water washability
- Surface to be applied (dry/scaly v.s. weeping skin)
Preparations of Ointments (2)
- Fusion
2. Incorporation
Fusion
- All or some of the components of an ointment are combined by melting together and cooled with constant stirring until congealed
- Highest MP substances are melted first then others follow in order based on MP
- Non-melting components are added during constant stirring in the cooling stages
Incorporation
- Components are mixed until uniform
- Can use a mortar and pestle or an ointment slab and spatula
Solids
- Use geometric dilution to combine base and fine powders (mixed in mortar/pestle) together uniformly
- Use levigation to mix solid material in a vehicle in which it is insoluble (like glycerin or mineral oil) to make a smooth dispersion
Liquids
- Need to consider base capacity to absorb liquid
- May use small amount of hydrophilic base (incorporated with liquid) to add to hydrophobic base
- Small amounts of alcohol solutions can also be added to oil bases
Compendial Requirements (5)
- Microbial content
- Minimal Fill
- Packaging
- Storage
- Labeling
Microbial Content
- Not sterile (unless ophthalmic), but has requirements
- Preservatives (Sorbic acid, phenols, Methyl or Propylparaben are examples)
- Preparations with water tend to have a larger chance of harboring growth
- Certain preparations are checked for specific agents
Dermatologicals + Microbial Content
Checked for P. Aerginosa and S. Aureus
Rectal/Urethral/Vaginal + Microbial Content
Checked for yeast and mold
Minimal Fill
Used to determine net weight and volume of contents of filled containers to ensure labeled amounts.