4_4TopTransderm3 Flashcards
(54 cards)
What are the advantages to transdermal patches?
1) well-documented release rate and amount, 2) long-term admin, 3) more practical and better control of dose/rate than ointment
What are the disadvantages of transdermal patches?
very expensive compared to ointment
What are the components of a patch?
1) drug reservoir, 2) rate-controlling membrane, 3) means of attachment
What are the characteristics of drugs employed in transdermal patches?
1) potency (most of drug isn’t released), 2) good permeability
What is the max surface area for a patch?
50 cm2
What are the concerns over transdermal patches?
1) poisonings, 2) abuse
How should a patch be disposed?
folded in half and disposed away from kids/pets
How are patches classified?
by release mechanism
What are the types of transdermal patches?
1) polymer membrane permeation controlled, 2) polymer matrix diffusion controlled, 3) drug reservoir gradient controlled, 4) micro-reservoir dissolution controlled
What is the RLS in polymer membrane permeation (PMP) controlled patches?
drug diffusion from polymer membrane
What is the most common polymer employed in RCMs?
ethylene vinyl acetate
What are the components of a PMP-controlled patch?
1) RCM (polymer), 2) adhesive layer spanning entire area, 3) drug reservoir
What are the components of a PMD-controlled patch?
1) drug/polymer matrix reservoir (no RCM); 2) adhesive RIM 3) occlusive baseplate, absorbent pad, impermeable plastic backing
What is the RLS in a PMD-controlled patch?
diffusion out of drug/polymer matrix reservoir (no RCM)
According to what do PMD-controlled patches release the drug?
square root of time
When are kinetics able to me estimated in a PMD-controlled patch?
only when loading concentration»_space; solubility in polymer
What is the RLS in a DRG-controlled patch?
diffusion out of polymer mixture
What are the components of a DRG-controlled patch?
1) drug/polymer reservoir gradients, 2) impermeable laminate backing
What are the components of a MRD-controlled patch?
1) adhesive RIM, 2) adhesive foam pad against occlusive baseplate, 3) polymer matrix reservoir of individual microscopic drug reservoirs
What is the RLS in an MRD patch?
diffusion of particles, dissolution of drug, or both
Future research in transdermal deliver focuses on what 3 classes?
1) hydrophilic drugs, 2) proteins and macromolecules, 3) vaccines and the immune response of the skin
What patch system is susceptible to an intial burst?
PMP-controlled (adhesive has drug incorporated to saturate drug-binding sites in skin)
What technologies are future methods of transdermal drug delivery?
1) low-pain microneedles, 2) iontophoresis, 3) ultrasound/sonophoresis/phonophoresis, 4) heat-induced permeation
Define iontophoresis
the facilitated transport of compounds across the skin using applied electrical field
