What are some examples of alchols and fatty acids?
What are some physcial methods that enhance percutaneous absorption?
delivery of charge chemicals across the skin using electrical field
High-frequency ultrasound facilitates drug penetration through the Stratum Corneum
What are some advantages of TDDS?
Avoid GI difficulties
Substitute ORAL administration
Avoid first-pass effect
Substitute parenteral therapy
Provide multi-day therapy with single application because they act as a reservoir of drug (better compliance)
Drug effects can be terminated by removal of system
Fast identification during emergencies
What are some disadvantages of TDDS?
Unsuitable for irritating and sensitizing drugs or highly sensitive persons, contact dermatitis
Only relatively potent drugs can be prepared as TDDS
Technical difficulties during preparations of TDDS
What are the two different designs of TDDS?
What is the monolithic system?
Most have excess drug, continual drug avaliabilty
The skin controls the rate of absorption of drug
Maintains wide range of plasma concentration over which the drug is effective but not toxic
Drug and molymer matrix (mixture) are blended or dissolved
Drug-matrix layer is dried, gelled matrix (sheet or cylindrical form)
Assembling between backing and frontal layers (foil cover-strip)
What is the membrane-controlled system?
The system controls the rate of drug delivery, rate -controlling membrane
Delivers uniform quantities of drug to the skin over a period of time
Drug in the reservoir (liquid or gell) remains saturated and the release rate of drug is constant
Adhesive layer contains an initial priming dose
Backing layer (water resistant) and drug reservior (liquid or gel) and Controlling semipermeable membrane and adhesive layer containing priming dose (holds the system onto the skin and protective peel strip
Used for motion sickness as antiemetic applied to the post-auricular area