Semisolid Lecture Flashcards
Define semisolid
Retain their shape until force is applied
Easily deformed
Touch of finger creates a track that does not refill after removal
Semisolid systems?
Ointments Solidified emulsions Creams Gels Magmas Rigid foam Pastes Plasters
Application sites?
Skin, eye, nose, vagina, rectum
- local effects
Define topical product
Deliver a drug to the skin and treat dermal disorders
Define transdermal product
Deliver drug via the skin to the general circulation
Define ointment
Hydrocarbon based
applied to skin
Medicated or non-medicated (protective and ;lube)
Ointment bases?
Oleaginous (oil based)
Absorption (water inside)
Water-removal (wash with water)
Water-soluble
Define oleaginous bases
Protects against moisture escape
Remain longer on skin
Difficult to wsh
Categories of oleginous bases
Petrolatum (semisolid, yellow petrolatum) White petrolatum (decolorized) Yellow ointment (mixture of petrolatum and yellow wax) White ointment (mix of petrolatum and white wax)
Define absorption bases
Absorbs water or aqueous solution without significant change in consistency
Types of absorption bases?
Emulsifiable bases: no water w/o with water (hydrophilic petrolatum)
Emulsion bases: w/o, allow incorporation of water (lanolin)
Define o/w emulsions
Removed from skin
Wash with water
PEG
Define incorporation with powder
Levigated (grinding an insoluble substance to a fine powder while wet)
Define incorporation with liquids
Water soluble mixed with water soluble bases up to a certain limit
- Add aqueous solution with a small amount of hydrophilic base and then mix with oleaginous base
Define fusion
All or some of the components are melted together and cooled with constant stirring
- Not melted are added to the congealing mixture as it cools upon stirring
Define emulsion base ointments
Oil-soluble ingredients are melted together
Water soluble ingredients are then mixed separrately
Aqueous phase is then added to oil slowly
Define reams
One or more med may be dispersed
- Looks creamy because it reflex light
Define vanishing cream
o/w emulsion with water, stearic acid and other oleginous components
Define pastes
Semisolid
- Larger amount of solid
Stiffer than ointment
- allows paste to remain in place after application
Define plasters
Solid or semisolid adhesive masses spread on a backing paper
Filling jars?
Filled by transferring weighed amount of the ointment into the jar with a spatula
Filling tubes?
Open back end of the tube, opposite the cap end
Define jelly
Coherent matrix is rich in liquid
Define xerogel
Liquid is removed and only framework remains
Gels can be?
Two phase or single phase
Inorganic or organic
Define two phase gels
“Magma”
- Consist of floccules of small and distinct particles
Define single phase gells
Consist of macromolecules existing as twisted or matted strands
No definite boundary
Strong vander Waals forces
Define inorganic gels
two phase
aluminum hydroxide
Define organic gels
Single phase
Condensed matrix is dissolved in liquid
Define hydrogel
water based
Gelatin
Define organogel
Organic liquid base
Petrolatum
Properties of gels
Syneresis (gels shrinks bc some liquid squeezes out)
Swelling (gel takes up liquid)
Imbibition (certain amount of liquid but no measurable increase in volume)
Define precipitation of dispersed phase
- Prepared by freshly precipitating the disperse phase
- Precipitation reduces the particle size
Define gelling agents
Forms gels upon contact with suitable solvent
Powdered gelling agents are mixed with the solution of the drug
- Heating and overnight hydration may be required
Bentonite magma?
Used as suspending agent
Aluminum hydroxide?
Antacid
- aqueous suspension of gelatinous precipitate insoluble aluminum oxide
Milk of magnesia?
Antacid
- Made by precipitates
