Pharmacology Flashcards

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1
Q

What is almost as important as the type of drug chosen in producing the therapeutic effect

A

The vehicle in which the drug is solubilised/ delivered

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2
Q

Drug administration via the skin can be used to treat systemic disease. True or false

A

True

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3
Q

What are the 3 major routes of administration for skin

A

Topical
Transdermal
Subcutaneous/ depot

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4
Q

What kind of effect do topical treatments have

A

local effect but also can treat underlying tissues

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5
Q

What type of effects do subcutaneous and transdermal treatments have

A

systemic effects (often prolonged)

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6
Q

What route of administration is required to reach the skin barrier

A

Depot injection

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7
Q

What is the single most important barrier to drug penetration

A

The stratum corneum

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8
Q

What does the stratum corneum consist of?

A

Hardened, dead, keratinocytes surrounded by intercellular lipids forming 10-30 sheets of tissue that are constantly shed and renewed

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9
Q

What are the corneocytes suspended in?

A

Lipids in lamellar structures / layers

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10
Q

What are the bricks in the Brick and Mortar Model

A

Corneocytes

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11
Q

What are adjacent corneocytes held together by? Where are these found?

A

corneodesmosomes (intercellular junctions)

living more inner layers of the skin

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12
Q

What is the mortar made up of?

A

intracellular lipids in an intensely hydrophobic environment

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13
Q

What is the ratio of different lipid content in the stratum corneum and why is this important?

A

1:1:1

any change in this can cause major changes to the skin

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14
Q

What can the mortar act as?

A

A reservoir for lipid-soluble drugs (topical steroids)

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15
Q

In what case does the drug have to travel across the stratum corneum

A

When you are trying to achieve either a local or a systemic effect.

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16
Q

What is meant by topical route of administration

A

when a drug is applied directly to the surface of the skin

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17
Q

When are topical drugs used?

A
superficial skin disorders - psoriasis and eczema 
skin infections 
itching 
dry skin
warts
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18
Q

Name some vehicles for topical routes of admisistration

A
ointments
creams
gels
lotions
pastes
powders
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19
Q

What dictates the choice of the vehicle

A
  1. Physicochemical properties of the drug

2. the clinical condition

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20
Q

What types of drugs are applied to relieve itching

A

H1 recepto antagonists

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21
Q

What is oftenused to treat dry skin

A

Moisturising agents

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22
Q

How do warts arise

A

Abnormal division of keratinocytes

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23
Q

What is the point in having vehicles

A

A vehicle which may be suitable for wet/ oozing skin is probably not suitable for dry skin

24
Q

Drug absorption across the skin is a passive process. true or false

A

true

25
Q

what can be described by Fick’s first law of diffusion

A

The rate of absorption of a drug across the skin

26
Q

What are 2 important facrots relating to the role of the vehicle

A

Solubility of the drug in the vehicle

Maximising the movement of the drug from vehicle to the stratum corneum

27
Q

What is Km

A

the equilibrium solubility of the drug in the stratum corneum relative to its solubility in the vehicle

28
Q

A very soluble drug will penetrate easily. true or false

A

false

29
Q

What type of base is vest for a lipothilic drug

A

Hydrophilic base

30
Q

What tends to break down the permeability barrier

A

hydration

31
Q

Are hydrophilic or lipothilic drugs better for absorption

A

lipothilic

32
Q

What provides the driving force for absorption

A

The soluble fraction of a drug

33
Q

Inclusion of what can enhance solubility and absorption

A

The inclusion of exipients

34
Q

Give an example of an excipient

A

propylene glycol

35
Q

Why are topically applied drugs generally poorly absorbed

A

Only a small fraction partitions into the stratum corneum

36
Q

What does an increased partitoning result from

A

a reduction in the barrier function of the stratum corneum

37
Q

What can be used to increase the solubility of hydrophobic drugs

A

Inclusion of excipients

38
Q

Name some factors that influence the absorption of topically applied drugs

A
The nature of the skin - the thickness 
Hydration of the skin
Integrity of the epidermis 
Drug concentration
The drug salt 
The vehicle
39
Q

Why can a pharmacist not substitute the vehicle

A

It has been prescribed just as much as the drug itself

40
Q

Why might a cream be used rather than an ointment

A

For cosmetic reasons

41
Q

Glucocorticosteroids signal via what and specifically what

A

Nuclear receptors - GRalpha

42
Q

What is meant by Subcutaneous Route

A

Drug delivered by a needle into the adipose tissue just beneath the surface of the skin

43
Q

What are some advantages of administering a drug subcutaneously

A

Absorption is relatively sore due to poor vascular supply
Route of adminsitration for many protein drugs (insulin)
Suitable for administration fof depot of drug under the skin that

44
Q

What is the main disadvantage of using subcutaneous route of administration

A

Injection volume is limited

45
Q

What are 4 advantages of a drug being administered topically for a systemic affect

A

Simple and non-sterile technique
Steady-state plasma concentration over a prolonged period of time
Avoids first pass metabolism
terminated rapidly

46
Q

What is meant by transdermal drug delivery

A

Drug is incorporated into a n adhesive patch and applied to the epidermis

47
Q

What 4 types of drugs is Trasdermal drug delivery useful for

A

low molecular weight
moderately lipophilic
potent
realtively brief half life

48
Q

What are some advantages of using transdermal drug delivery

A

Relatively few drugs are suitable

Chance of allerfies and cost

49
Q

Name some drugs wihch are administered transdermally

A

nicotine
GTN
fentanyl
estradiol

50
Q

WHat is the puropse of using chemical enhancements in transdermal drug delivery

A

Increases permeability
Low cost
Can be incorporated into vehicles

51
Q

What are some disadvantages of transdermal drug delivery

A

Skin irritation/ toxicity

Not effective for highly water soluble drugs

52
Q

What agents tend to be used to enhance

A

Water - prolonged occlusion

A variety of solvents and surfactants (ethanol, and sodium dodecyl sulphate

53
Q

What is iontophoresis

A

application of low voltage electrical pulses to the skin via a surface electrode over a prolonged period of time

54
Q

What is meant by electroporation

A

very brief high voltage pulses lead to pore formation. Has the potential for the delivery of hydrophilic and changed molecules into the skin

55
Q

what is sonophoresis

A

the use of ultrasound to increased skin permeability

56
Q

How do microneedles work

A

they punch microscopic holes i nthe skin - largely experimental