Drug Movement Across Biological Membranes Flashcards

1
Q

Amphipathic phospholipids are not very permeable to what?

A

polar (charged molecules)

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2
Q

What part of the phospholipid molecule is the phosphate containing group?

A

the hydrophilic part (polar head)

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3
Q

What part of the phospholipid molecule is the carbon chain?

A

the hydrophobic part (non-polar tail)

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4
Q

True or false: Not all polar things are charged, but all charged things are polar.

A

true

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5
Q

What is the most important mechanism for the passage of drugs across membranes?

A

passive diffusion

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6
Q

What type of molecules will diffuse through the lipid bilayer?

A

non-polar molecules

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7
Q

In the oil-water partition coefficient, what would increased polarity be due to?

A

hydroxyl and amine groups

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8
Q

In the oil-water partition coefficient, what would the decreased polarity be due to?

A

methyl groups

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9
Q

What does the association constant describe?

A

the constant relationship between the relative concentrations of protons, the unprotonated acid, and the protonated acid

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10
Q

What is pKa?

A

the pH at which 50% of the molecule is protonated

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11
Q

What is an acid?

A

a proton donor

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12
Q

When is an acid in its protonated form?

A

when there is a proton associated with a weak acid, it is non-ionized, non-charged, and non-polar

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13
Q

In what environment is an acid protonated?

A

in low pH

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14
Q

What is a base?

A

a proton acceptor

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15
Q

When is a base in its protonated form?

A

if there is a proton associated with a weak base, it is ionized, charged, and polar

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16
Q

In what environment is a base protonated?

A

in low pH (it is in the presence of lots of protons)

17
Q

In what kind of environment would most weak acids be able to cross membranes?

A

low pH

18
Q

In what state would a weak acid tend to be when it gets into a higher pH environment?

A

it will be unprotonated and therefore will not be able to pass back across the membrane