Pharmacology Flashcards
What are the two routes a drug can take to cross the skin?
Transcellular and intercellular.
What are the three depths of drug administration through the skin?
Topical- Local effect
Transdermal- Systemic effects
Subcutaneous- Systemic effects
What is the major barrier to drugs penetrating the skin?
Stratum corneum- keratin layer
Out of transcellular and intercellular which route is most common?
Intercellular
What must a drug be to pass though the intercellular route?
LMW and lipophilic
List the 7 forms topical treatment can take.
Ointments Creams Gels Lotions Pastes Powders Foams
What factors must be considered when picking a vehicle?
Skin condition
Drug
Patient preferences
Why is there an excess of undissolved drug?
As dissolved drug is absorbed the undissolved drug becomes dissolved thus giving a steady supply for a long time.
How can the absorption of drugs be increased topically.
Skin hydration
Inclusion of excipients to increase solubility.
Drug salt form
Choice of vehicle
What are the advantages of topical treatments?
Direct application to required area
Reduced systemic effect
What are the disadvantages of topical treatments?
Time consuming
Dosing difficulties
Messy
What is a cream?
Semisolid emulsion of oil in water containing emulsifiers and preservatives. Non greasy with high water content.
What is an ointment?
Semisolid grease or oil with no preservatives. Good for preventing water loss.
What is a lotion?
Suspension of drug in water or alcohol. Treat hairy areas.
What is a gel?
Semi-solid aqueous solution containing high molecular weight polymers. Treat face and hairy areas.
