Lecture 2 concept notes Flashcards

1
Q

What do physiochemical properties of a drug influence?

A

Their pharmacokinetics and their pharmacodynamics

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2
Q

What are some factors that affect the kinetics and dynamics?

A

The acid/base properties of the drug
the water solubility
the partition coefficient
the stereochemistry

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3
Q

Lipinski’s Rule of Five

A

A guideline or gold standard for making an ideal drug

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4
Q

Drug should have a Molecular Weight of ____ or below?

A

500

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5
Q

Drug should have _____ than _____ H-bond donating functional groups ?

A

Fewer than 5 H-bond donating groups

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6
Q

Drug should have ____ than ____ H-bond accepting functional groups?

A

Fewer than 10 H- bond accepting groups

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7
Q

Drug should have a calculated ____ of ____than 5?

A

LogP less than 5

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8
Q

The larger the LogP the ____?

A

the more hydrophobic the drug is

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9
Q

Life cycle of a drug

A

Can be taken orally, absorbed through the GI tract or through injections, will have a systemic effect, and then taken to the liver to be metabolized

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10
Q

What happens to a drug if it binds to an unintended receptor?

A

IF the drug is an ideal drug, it will survive this binding.

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11
Q

Why does a drug need to be hydrophilic as well as lipophilic?

A

The body has both aqueous and lipid phases that the drug needs to pass through. Aqueous = bodily fluids like blood. Lipid= Bilayer

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12
Q

If a drug binds to an unintended receptor and degrades, is it an ideal drug?

A

No. an ideal drug needs to be able to survive binding to inert sites.

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13
Q

What does a drug have to do until it reaches the intended receptor or site of action?

A

Has to penetrate until the site of action

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14
Q

Name the criteria for ideal drugs

A

Soluble in water
Able to pass through lipid bilayers
Survive binding to inert or unintended receptors
Endure metabolic modifications
Penetrate until the site of action
bind to the right receptor & have the intended biological response

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15
Q

How do functional groups affect a drug?

A

Can affect the pharmacodynamics and kinetics of the drug

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16
Q

How does the acidity or basicity of a drug affect it?

A

It will affect the ADME of the drug

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17
Q

Most drugs with a pKa outside of 5-9 tend to be strongly ionized. What does this mean for absorption across the membrane?

A

The drug will not be permeable to the membrane. It will be too polar to pass, and thus hydrophilic. In order to pass the membrane, the drug needs to be lipophilic and this non-polar.

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18
Q

how can we change the solubility of a drug?

A

We can modify the drug’s structure by adding functional groups that are acidic or basic.

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19
Q

Salt formation can ___ (increase//decrease) water solubility

A

Can increase water solubility.

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20
Q

Ionizable drugs

A

Usually have at least one basic group

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21
Q

Use other deck for acidic and basic drugs

A

(sengshang lin) memorize now.

22
Q

acidic drugs?

A

penicillin
phenobarbital
vitamin c
aspirin
phenytoin
boric acid

23
Q

Basic drugs

A

Caffeine
zalcitabine
morphine
erythromycin
amphetamine

24
Q

Use Anki for functional groups

A

memorize now.

25
Q

Acid/base theory

A

Acid- donates a proton
base- accepts a proton

26
Q

How to determine percent ionization?

A

Using the formulas derived from Henderson hasselbach

27
Q

ionization formula for an acidic drug?

A

It will have a (-) charge since it donates a proton

% ionization = 100/ 1+ 10^pka-pH

28
Q

ionization formula for an basic drug

A

It will have a (+) charge since it accepts a proton
% ionization = 100/ 1+ 10^pH-pKa

29
Q

Acidic drugs in an acidic environment

A

will be non-ionized

30
Q

Acidic drugs in a basic environment

A

will be ionized

31
Q

Basic drugs in a basic environment

A

will be non-ionized

32
Q

Basic drugs in an acidic enviornment

A

Will be ionized

33
Q

Lipophillicity

A

Important property in the ADME profile
Can affect solubility, adsorption, etc

34
Q

Partition Coefficient

A

Helps determine the absorption of the drug in the body

35
Q

The higher the partition coefficient, the ___ the absorption?

A

The higher the absorption in the body

36
Q

The lower the partition coefficient, the ___ the absorption?

A

the lower the absorption in the body

37
Q

logP

A

the partition coefficient

38
Q

logP is a measure of ____ in the absence of ___?

A

logP is measured in the ABSENCE of ionization.
It is a measure of how much of the drug has an affinity for the lipid and aqueous phases of a solution.

39
Q

Why is 1-Octanol is commonly used to measure logP?

A

It has polar and non polar regions. Mimics the bilayer, and P is easy to measure.

40
Q

Distribution Coefficient

A

Takes into account ionization. **
The partitioning of a molecule between the lipid and aqueous phase will depend on the pH.

41
Q

What does the distribution coefficient take into account?

A

The lipophillicity of the drug as well as the degree of ionization at a given pH

42
Q

What does aqueous solubility depend on?

A

It depends on the ionization of functional groups as well as their H bond properties

43
Q

How can we improve solubility

A

Decrease logP. Recall that a higher logP = more hydrophobicity. We want a lower logP so we will have less hydrophobic properties in the drug

44
Q

How can we decrease logP

A

By increasing ionizable groups, H-bonding groups and more polar groups

45
Q

How else can we improve solubility

A

Reduce crystal packing. Preventing molecules from tightly packing together will make it more soluble

46
Q

Organic vs Inorganic salts

A

Organic salts = Carbon containing
Inorganic salts= no-carbons

47
Q

Which is more soluble? Organic or inorganic?

A

Inorganic salts are more soluble

48
Q

What are some factors that will cause a drug to not reach the intended site of action?

A

Protein binding
Binding to neutral fats
Drug metabolism
and
Excretion

49
Q

Protein Binding

A

Drugs can bind to proteins like albumin and it is reversible. However, once bound, the drug cannot pass through lipid membranes and will spend longer in the body without doing anything. When unbound, it can then be metabolized or excreted

50
Q

Clinical significancee of protein binding

A

Warfarin can be displaced from its binding site by drugs like sulfonamides. this is a drug drug interaction

51
Q

Which type of drugs will bind to neutral fats

A

Drugs that are lipophilic are more likely to deposit in neural fats and then will slowly redistribute to the fattu tissue.