Lecture 5&6: ointments Flashcards
Tylenol/APAP toxicity to animals
Cats
Chocolate and grape flavoring toxicity to animals
Dogs
Xylitol toxicity to animals
Dogs and birds
profound hypOglycemia
hepatocellular necrosis
Compounding needs for animal Rx
Dosage form
taste issues (tuna/beef flavoring)
mixing multiple medsfor easier application
customize dose
avoid toxicities in excipients of readily available Rxs
Common errors in vetinary dispensing
- identify breed of animal
- Identify occupation/intended use
Companion animal
least restriction of drug use
Performance animal
service, military/police, competitive sport
Food producing
drug use is strictly regulated and causes serious penalties if violated
AMDUCA: animal medicinal drug use claification act
AMDUCA
Animal medicinal drug use clarification act 1996
1. must have relationship between prescriber and animal/client (CVPR)
2. Avoid drug residues in the food chain for food producing animals
Algorithm for vet rx
check for all components:
1. licensed practitioner name, address, telephone, DEA if CS (vets don’t have NPI)
2. Owner name and info
3. Animal species/breed, DOB, weight, gender
4. Drug name and strength, directions, refill #
Banned medications in food producing animals that have toxicities to humans
chloramphenicol, diethylstilbesterol, fluoroquinolones, etc
“abx free chicken”
ointments
compounded
semisolid preps for external application to the skin or mucous membrane
pastes, gels, plasters, etc
Common uses for compounded ointments
protect skin/mucuous membrane
provide hydration (emolient)
vehicle for medication (local vs systemic)
Local ointment
antibiotic
Systemic ointment
nitroglycerin
Choosing an ointment base
decision depends on:
1. ointment use
2. properties of medication being incorporated
3. area of application
5 types of ointment bases
- hydrocarbon/oleaginous
- anhydrous
- water in oil emulsion
- oil in water emulsion
- water soluble
Compounding materials for ointments
- Slabs>pads
- metal spatula>plastic (unless rxn w/ metal like iodine)
- large scale - use mills or electric mixers
Levigating agents
reduce particle size by triturating w/ small amount of immicible liquid
Required to:
1. make ointment smooth elegant
2. adequately wet the solid (viscous, low surfance tension)
3. ex: mineral oil, glycerin, propylene glycol, PEG400, cottonseed oil, castor oil, etc
4. solid must be insoluble in levigating agent
Dissolution
- solid powder must be soluble in solvent
- solid dissolved in solvent prior to adding to ointment base
- absorption base is used to absorb the aqeuous solution
When are levigating agents NOT required?
- solid is very fine particle
- small quantity
- soft ointment base
- ointment intended to be a stiff paste
Ideal properties of ointment
- spreads easily
- compatible w/ toipcal use (hypoallengergic)
- stable (no bacteria)
- smooth and pliable (not hard or runny)
- softens/melts at room temp
- readily released medication
- easily removed (doesn’t stain clothing)
what increases drug release and penentration into the skin?
semisolid dosage forms
- more pressure
- greater surface area
- broken skin/open wound (thin = systemic adr)
- type of base (depends on drug)
- use of occlusive dressing
Dissolution examples
- solid, water-soluble powder –> petrolatum
— dissolve in distilled water - solid, oil-soluble powder –> petrolatum
– dissolve in mineral oil
anhydrous ointment bases
more challenges
not as washable
spreads less
more occlusive (protectant)
can incorporate fewer drugs
poor release of polar drug
hydrous ointment bases
spreads more easily
more washable
not as occlusive
more drugs can be incorporated (but not oils)
better release of polar drugs
Anhydrous vs hydrous base
most of the time hydrous > anhydrous
Types of anhydrous bases
hydrocarbon (white petrolatum, white ointment)
anhydrous (hydrophillic petrolatum, anhydrous lanolin, aquaphor, aquabase)
water soluble (PEG ointment, polybase)
Types of hydrous bases
Water/oil (cold cream, hydrous lanolin, hydrocream, eucerin)
oil/water (dermabase, velvachol, unibase)
water soluble (PEG ointment, polybase)
Hydrocarbon
white petrolatum
white ointment
Anhydrous
hydrophillic petrolatum
anhydrous lanolin
aquaphor
aquabase
Water/oil base
cold cream
hydrous lanolin
hydrocream
eucerin
oil/water base
dermabase
velvachol
unibase
Water soluble
PEG ointment
Polybase
Ointment compounding
depends on # of ingredients
1-2 ingredients: mix everything together
3 or more ingredients: add sequentially to base (geometrically)
ointment: choosing agent
must be chemically similar to ointment base
always use minimal amount of levigating agent unless otherwise specified by the prescriber
ointment: dissolution
dissolve solid in solvent prior to adding to ointment base when:
1. solids are hard to incorporate
2. powdered solid must be soluble in solvent
always use smallest amount of solvent (based on dissolution data)
ointment: adding liquid to ointment
- must be carefully spatulated or triturated into base
- place semisolid base on slab, create depression
- pour liquid in, keep contained
- spatulate in small proportions until well incorporated
ointment procedure
depends
