topical transdermal revised

Question 1

living dermis

Answer 1

living cells without capillaries
cells get nutrition by diffusion from dermis
source of skin color and tanning

Question 2

dermis

Answer 2

contains capillaries
drug needs to reach these capillaries to achieve systemic action
contain pain, thermal, and tactile sensors
injury must reach dermis to produce scarring

Question 3

hair follicles and sweat glands

Answer 3

secondary route of drug absorption that bypasses the stratum corneum

Question 4

stratum corneum

Answer 4

main (lipid) barrier to permeation
brick and mortar model (dead cells and lipid)

Question 5

transdermal permeation

Answer 5

state of hydration is directly related to ease
occurs by partitioning through the lipid material between the dead cells

Question 6

functions of the skin

Answer 6

containment
microbial barrier
chemical barrier
radiation barrier
electrical barrier
thermal barrier
body temp regulation

Question 7

microbial barrier function

Answer 7

pH of skin is 5, inhibiting growth of bacteria
sebum contains bacteriostatic and fungistatic fatty acids

Question 8

electrical barrier function

Answer 8

offers high impedance to the flow of an electrical current
needs to treat the skin with salt solution (granular salt suspensions, creams, pastes containing electrolytes) to overcome impedance and measure body potentials

Question 9

reason for topical drug delivery

Answer 9

local effects (surface vs stratum corneum)
drug action on the skin’s glands
effects in deep tissues

Question 10

local SURFACE effect examples

Answer 10

zinc oxide paste for diaper rash
sunblock and sunscreen
lip balm for chapped lips
calamine lotion for poison ivy and poison oak
antibiotics
deodorant
medicated soap

Question 11

local STRATUM CORNEUM effect examples

Answer 11

emolliency – softening of horny tissue
keratolysis – chemical digestion and removal of horny tissue

Question 12

drug action on skin’s gland

Answer 12

antiperspirants (aluminum chloride)
acne (soap, alcoholic solutions, antibiotics)
hair removers (depilatories)

Question 13

retinoid

Answer 13

prevent the formation of lesion by resetting the process of epidermal proliferation and differentiation

Question 14

effects in deep tissues

Answer 14

topical corticosteroids
NSAIDs (diclofenac)
local anesthetics (benzocaine)
lighten excessively pigmented skin (hydroquinone)
skin cancer (5-flurouracil

Question 15

reason for transdermal drug delivery

Answer 15

systemic purposes

Question 16

topical systems

Answer 16

ointments
pastes
creams
gels
rigid foams

Question 17

types of ointments

Answer 17

hydrocarbon based (most hydrophobic, petrolatum)
silicone based
absorption based (O/W)
water soluble based (most hydrophilic)

Question 18

pastes

Answer 18

ointments into which a high concentration of insoluble particulate solids are added

Question 19

gels

Answer 19

liquid phase trapped in matrix of natural or synthetic polymer (like tragacanth, pectin, carrageenan, methylcellulose, carboxymethylcellulose, carbopol)
example - topical scalp gel

Question 20

rigid foams

Answer 20

air or other gas emulsified in liquid phase that contains the drug
examples - aerosol shaving creams, medicated quick-breaking antiseptic foams

Question 21

drugs suitable for transdermal delivery

Answer 21

drugs with a short systemic half-life, undergo extensive first pass metabolism, thus requiring frequent dosing
high skin permeability
low dose requirement
drug is small and hydrophobic

Question 22

factoring affecting drug permeability

Answer 22

correlates to drug’s MW and Ko/w
hydration (more hydrated, greater permeability)
solubility of drug
excipients
pH (affects drug ionization status)

Question 23

black box warning for xulane patch

Answer 23

cigarrette smoking and serious CV risks
risk of VTE
PK profile - 60% higher in women using norelgestromin and EE transdermal system compared to women using an OC (but peak conc is 25% lower)

Question 24

methods to improve transdermal drug delivery

Answer 24

iontophroesis
electoporation
ultrasound
prodrugs
(chemical) penetration enhancers
ionic surfactants
ascorbate, dithiothreitol
azone
dimethyl sulfoxide (DMSO)
microneedles

Question 25

iontophroesis

Answer 25

use low voltage electrical current to drive charged drugs through the skin

Question 26

electoporation

Answer 26

use high voltage to create transient pores in teh skin
early stage, but works well

Question 27

ultrasound

Answer 27

use low frequency ultrasonic energy to disrupt the skin (Stratum corneum)

Question 28

ionic surfactants

Answer 28

disorder the lipid layer of stratum corneum to swell and/or leach out some of the structural components
reduces the diffusional resistance

Question 29

ascorbate, dithiothreitol

Answer 29

reducing agents
disrupt disulfide bonds of protein keratinized cells

Question 30

azone

Answer 30

nonpolar oily liquid
fluidize intracellular lipid lamella region of stratum corenum

Question 31

DMSO

Answer 31

dipolar solvent
enter aqueous region of stratum corneum to interact with the lipid polar heads
expands hydrophilic region between the polar heads

Question 32

microneedles

Answer 32

pretreatment to increase skin permeability before the subsequent application of drug loaded patch
coated with drug that is released from teh needles while skin embedded
hollow ones have been made to flow drug solutions in the skin

Question 33

potential patch patient errors

Answer 33

must be applied directly to skin
must remove protective liner
must be only one patch at a time
must not cut
where to place
when to change
usage of transparent patches
preparation
removal
application
monitoring (influence of heat, patch displacement)
storage and disposal