ceutics transdermal 2

permeation enhancer

increase permeability of stratum corneum

how can solvents increase penetration

swell polar pathway and fluidize lipid

= enhance uptake of hydrophilic compounds

ex: methanol, ethanol, DMSO, DMA

t/f: ethanol can increase drug penetration by fluidizing lipid and increasing uptake of hydrophilic drugs

true

surfactants increase penetration of _________ drugs

hydrophilic

examples of anionic and cationic surfactants in TDDS

anionic= dioctyl sulpho succinate, SLS, decodemethyl sulphoxide

cationic= pluronic F127, pluronic F58

_________ is the permeation of IONIZED drugs via electrical current

iontophoresis

describe how iontophoresis works

1. current passed between active electrode (has API applied) and inactive electrode

2. repels drug AWAY from the active electrode and into skin

= used for ionized drugs than cannot past lipophilic skin

advantages of iontophoresis

-enhanced drug penetration

-control of penetration rates

-rapid termination of drug delivery

-skin remain intact (low infection risk)

t/f: iontophoresis has a lower risk of systemic absorption compared to injection

true

t/f: iontophoresis bypasses the first pass effect

true

reverse iontophoresis

current causes an ion(API) to enter and to escape(analyte)

-allows analyte sampling and drug delivery

ex: glucose devices

sonophoresis/ phonophoresis

ultrasound sends waves through the skin to assist in product penetration

(iontophoresis uses electrical charge, this uses sound waves)

Phonophoresis/sonophoresis mechanism

1. ultrasound waves pass through skin= fluidizes lipid bilayer and forms bubbles (cavitation)

2. cavitation allows hydrophilic drugs to pass through

electroporation

electrical pulse produces hydrophilic pores in between skin cells by realigning lipids momentarily

which technique forms hydrophilic pores in the s. corneum by realigning lipids and allows larger drug molecules to pass through

electroporation

what is peel adhesion

force required to remove adhesive coating

peel adhesion properties are affected by

1. molecular weight of adhesive

2. additives

3. polymer composition

how is peel adhesion evaluated

measuring the force required to pull a single coated tape at 180 degree angle

tack vs peel adhesion

tack= ability to adhere with no pressure

peel adhesion= force required to remove adhesive

3 tests for tack

1. rolling ball test: stainless steel ball rolled down ramp, with adhesive applied to flat floor. measure distance

2. quick-stick(peel-tack): peel force required to break bond measured by pulling tape at 90 degree angle at 12inch/min (higher value= more tack)

3. probe tack test: force required to pull probe away from adhesive

_______ is the measurement of the cohesive strength of an adhesive polymer

shear strength/creep resistance

how is shear strength/ creep resistance determined

measuring the time it takes to pull an adhesive tape with weight off of stainless steel plate

**no force applied here, just changing the weight on the adhesive

in-vitro drug release evaluation uses _______ skin

hairless mouse skin

franz-diffusion cell mechanism

measures the diffusion of drug past skin into receptor chamber

franz-diffusion cell advanatges

-helps study drug permeation through skin

-time for steady state permeation obtained

-preliminary for in-vivo studies

- more easy, less expensive, no complications (compared to in vivo)

2 types of contact dermatitis: definition and tests

1. Irritant Contact Dermatitis (ICD)

=results from direct toxic injury to cell

a. 10 day primary irritation test

b. 21 day irritation test

2. Allergic Contact Dermatitis (ACD)

=immunology rxn to antigen

a. guinea pig maximization test

microarray needle patch TDDS

needles 1) coated with drug or 2) hollow and filled with drug, penetrate s. corneum and epidermis without reaching nerve endings in dermis

=400 microneedles

=increase in flux up to 100,000x

= creates painless micropores through which water soluble drugs pass through

micro trans TDDS can deliver? sense?

-large proteins, antibodies, hormones

-small molecules hard to diffuse

-vaccines

senses: glucose, hormones, gases, drug levels

t/f: a micro trans can both sense and deliver drugs

true

crystal reservoir technology

-oversaturates polymer with a drug= forming crystals

-both molecular and crystal state allows high concentration and constant drug supply

- as skin absorbs dissolved drug, the crystals re-dissolve to maintain solubility limit

-smaller and thinner patch

which TDDS results in a smaller and thinner patch

crystal reservoir