Pharmacology Flashcards

1
Q

What aare adjacent corneocytes held together by?

A

corneodesmosomes

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2
Q

What is conventional transdermal drug delivery driven by?

A

diffusion

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3
Q

What is Fick’s Law?

A

Rate of absorption (flux) is equal to the permeability coefficient times the concentration of drug

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4
Q

What are the important factors in the role of the vehicle?

A

The solubility of the drug in vehicle (Cy)

Maximising the movement of the drug from vehicle to the atratum corneum (drug must escape from vehicle)

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5
Q

What is the permeability coefficient (Km) described as?

A

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

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6
Q

What is the purpose of excipients?

A

They are put into the vehicle to enhance the solubitliy of the drug and so enhance absorption

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7
Q

Why might excess, non-dissolved drug be included into transdermal patches?

A

increases duration of effectiveness nad porvides a constant rate of delivery- dissolved drug that is removed by absorption is replaced by undissolved drug maintaining a fairly constant soluble concentration

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8
Q

Why are topically applied drugs generally poorly absorbed?

A

only a small fraction partitions into the stratum corneum

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9
Q

Name some factors that can improve partitioning

A

hydration of the skin by occlusion (increases the reservoir with which the drug can be absorbed)
inclusion of excipients which also increase the solubility of hydrophobic drugs

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10
Q

What are the factors that affect the absorption of topically applied drugs in drug preparation?

A
drug conc.
the drug salt (different salts can have varying potencies)
the vehicle (can affect how active a drug is)
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11
Q

What do glucocorticoids combine with in the cytoplasm?

A

GRalpha

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12
Q

What does combination of steroid with GRalpha cause the dissociation of?

A

inhibitory heat shock proteins

they were previously joined to GRalpha but steroid kicks it out

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13
Q

What does the steroid and GRalpha do in the nucleus?

A

bind to the glucocorticoid response elements which switches on or off transcription of specific

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14
Q

Where is subcutaneous drug delivered?

A

adipose tissue just beneath teh surface of the skin

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15
Q

How does subcutaneous drug reach systemic circulation?

A

diffuses into capillaries or lymphatics

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16
Q

What are some advantages to subcut drug administration?

A

absorption is relatively slow (poor vascular supply)

can be used to introduce a depot of drug under the skin that is very slowly released into the circulation

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17
Q

What is an advantage of subcut drug administration?

A

injection volume is limited

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18
Q

What is the skin a good route for a systemic effect?

A

avoids first pass metabolism

drug absorption can be terminated rapidly

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19
Q

What makes a drug suitable for transdermal drug delivery?

A

low molecular weight
moderately lipophilic
potenet
relatively brief half life

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20
Q

What is iontophoresis

A

application of low voltage electrical pulses to the skin via a surface electrode over a prolonged period of time can drive low molecular mass molecules (of the same charge) through the skin- move away from the same charge

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21
Q

What is electroporation?

A

very brief high volatge pulses lead to “pore” formation

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22
Q

What is sonophoresis?

A

use of ultrasound to increase skin permeability

23
Q

What is a cream?

A

semisolid emulsion of oil in water

24
Q

Creams contain both an emulsifier and a..

A

preservative

25
Due to their high water content, creams do what to the skin?
cool and moisturise
26
What is an ointment?
semisolid grease/oil (soft paraffin)
27
Do ointments contain preservative?
no
28
Why do ointments help to moisturise the skin?
occlusive- restrict transepidermal water loss
29
What is a lotion?
a liquid formulation- suspension or solution of medication in water, alcohol or other liquids
30
What areas are lotions used to treat?
scalp and other hair-bearing areas
31
What is a gel?
semi-solid, thickened aqueous lotions containing high molecular weight polymers
32
What areas are gels used to treat?
scalp, hair bearing areas, face
33
What are pastes?
semisolids, contain finely powdered material
34
What are the advantages of pastes?
protective, occlusive hydrating
35
What does an emollient do?
enhance rehydration of epidermis
36
What kind of conditions are emollients used for?
all dry/scaly conditions esp. eczema and psoriasis
37
What is wet wrap therapy used for?
very dry (xerotic) skin
38
What are the modes of action of corticosteroids?
vasoconstrictive anti-inflam antiproliferative
39
What are topical corticosteroids used for treating?
eczema psoriasis other non-infective inflammatory dermatoses- lichen planus keloid scars
40
What are the skin side efects of topical steroids?
thinning of the skin; purpura; stretch marks; atrophy; steroid rosacea; perioral dermatitis; fixed telangiectasia
41
What are other non-skin related effects of topical steroids?
may worsen/ mask infections systemic absorption tachyphylaxis- decrease in response to anti-inflam effects rebound flare of disease (esp. psoriasis)
42
What are antiseptics used for?
recurrent infections antibiotic resistsance wound irrigation
43
What conditions are topical antibiotics used for?
acne rosacea impetigo infected eczema
44
What conditions require an oral antiviral?
eczema herpeticum; herpes zoster
45
What are topical antifungals used to treat?
candida dermatophytes (ringworm) pityriasis versicolor
46
Name 4 antipruritics
menthol capsaicin (red chilli peppers) camphor/phenol-pruritis ani (around the anus) crotamiton
47
What are keratolytics used for?
viral warts hyperkeratotic eczema and psoriasis corn and calluses to remove keratin plaques in scalp
48
What topical treatments can be used to treat psoriasis?
emollients and - coal tar - vit D analogue - keratolytic - topical steroid - dithranol
49
What is the mode of action of imiquimod?
enhances innate and cell- mediated immunity and so has anti-viral and anti-tumour effects
50
What is imiquimod used to treat?
viral warts and superficial BCC
51
What do calicneurin inhibitors do?
suppress lymphocyte activation
52
what are calicneurin inhibitors used to treat
atopic eczema esp face and in children
53
What are the side efects of topical therapies?
burning or irritation contact allergic dermatits local toxicity systemic toxicity
54
How many grams is needed for an adult to cover the whole bodyin ointment?
30g