unit 3 Flashcards

1
Q

The biological activity of a targeted drug molecule is solely dependent on its physicochemical characteristics, essentially the ___ and ____

A
  • NATURE AND TYPE OF FUNCTIONAL MOIETIES
  • SPATIAL ARRANGEMENT
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2
Q

Modulating the structure of a drug implies ___,___,___ of certain groups in the drug.

A

INTRODUCTION
ELIMINATION
SUBSTITUTION

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3
Q

It plays an important role in modifying the biological activities of many compounds.

A

PHYSICOCHEMICAL PROPERTIES

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4
Q

Substances that are present at the same proportional saturation in a given medium have the same degree of biological action

A

FERGUSON PRINCIPLE

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5
Q

According to ___, it is unnecessary neither to define the nature of the biophase or the receptor nor to to measure the concentration of the drug at this site.

A

FERGUSON

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6
Q

If equilibrium conditions exist between the drug in molecular biophase and in extracellular fluids, the tendency to escape from each phase is the same, even though the concentrations in the two phases are different.

A

THERMODYNAMIC ACTIVITY

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7
Q

It is approximately equivalent to the degree of saturation of each phase

A

THERMODYNAMIC ACTIVITY

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8
Q

It is a bond in which a hydrogen atom serves to hold two other atoms together.

A

HYDROGEN BOND

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9
Q

The H-bond is usually formed only between:

A

HYDROGEN AND ELECTRONEGATIVE ATOMS

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10
Q

Most common atoms capable of forming H-bonds

A

FLUORINE
OXYGEN
NITROGEN

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11
Q

Atoms capable of forming H-bonds to a lesser extent:

A

CHLORINE
SULFUR

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12
Q

The compounds that are capable of forming hydrogen bonding are only:

A

SOLUBLE IN WATER

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13
Q

The hydrogen bonds occur within one molecule

A

INTRAMOLECULAR HYDROGEN BONDING

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14
Q

The hydrogen bonds occur between two or more molecules

A

INTERMOLECULAR HYDROGEN BONDING

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15
Q

They are frequently much weaker than the other.

A

INTERMOLECULAR; INTRAMOLECULAR

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16
Q

It would greatly increase its potential for aqueous solubility.

A

MULTIPLE HYDROGEN BONDING GROUPS IN ANY DRUG MOLECULE

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17
Q

It is essential for all the drug molecules to transport to the site of action on a receptor.

A

MINIMAL AQUEOUS SOLUBILITY

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18
Q

H-bond strength of acetic acid dimer in vapour state

A

7.64 kcal/mol

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19
Q

H-bond strength of acetic acid dimer in benzene

A

4.85 kcal/mol

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20
Q

In water, the h-bond strength is:

A

4.5 kcal/mol

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21
Q

In ice, the bond strength is:

A

6 kcal/mol

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22
Q

The physical states of substances, such as water, DNA, protein and various drug molecules are maintained by:

A

HYDROGEN BONDING

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23
Q

The most frequently observed H-bonds in biological systems are between the:

A

HYDROXYL (OH)
AMINO (NH)

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24
Q

No analgesic property
Melting point: 127 degrees C
Insoluble in Water
Slightly soluble in Ether
Forms intermolecular H-bond

A

1-Phenyl-3-methy-5-pyrazolone

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25
Q

Good analgesic agent
Melting point: 112 degrees C
Soluble in Water
Moderately soluble in Ether
Does not form intermolecular h-bond

A

1-Phenyl-2,3-dimethy-5-pyrazolone (antipyrine)

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26
Q

Increase in ionization INTENSIFIES A DRUG’s WATER SOLUBILITY and DECREASES ITS LIPOSOLUBILITY

A
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27
Q

Drugs cross cellular membranes in UNDISSOCIATED forms as:

A

INTACT MOLECULES

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28
Q

Drugs cross cellular membranes in DISSOCIATED form as:

A

IONS

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29
Q

Are predominantly of the UNIONIZED form at the LOWER pH of the gastric fluid, and absorbed from the stomach as well as intestine.

A

WEAKLY ACIDIC DRUGS

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30
Q

Some very weak acidic drugs whose pKa are greater than 7 and are unionized at all pH values

A

PHENYTOIN
MANY BARBITURATES

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31
Q

They are poorly absorbed in the stomach since they are present largely in the ionized form at low pH

A

MOST WEAK BASES

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32
Q

Those with pKa values between 5 and 11, shows pH dependent absorption.

A

STRONG BASE

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33
Q

This stronger base has a pKa > 11 and are ionized throughout the gastrointestinal tract and tend to be POORLY ABSORBED.

A

GUANITHIDINE

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34
Q

The liposolubility is affected by pH of the environment medium and by the degree of dissociation pKa.

A
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35
Q

The degree of dissociation, pKa, is calculated from the following equation.

A

HENDERSON-HASSELBALCH EQUATION

36
Q

STRONG ACID - LOW PKA VALUE
WEAK ACID - HIGH PKA VALUE

A
37
Q

STRONG BASE - HIGH PKA VALUE
WEAK BASE - LOW PKA VALUE

A
38
Q

It may be defined as a quantitative expression of the tendency of a compound that has to give or receive electrons.

A

REDOX POTENTIAL

39
Q

Redox Potential equation

A

Eh = E10 - 0.06 / n

40
Q

Eh =
E10 =
n =

A
  • REDOX POTENTIAL OF THE SYSTEM BEING STUDIED
  • STANDARD POTENTIAL AT GIVEN PH
  • NUMBER OF ELECTRONS TRANSFERRED
41
Q

It means greater tendency for reduction to occur.

A

HIGHER EO

42
Q

It means greater tendency for oxidation to occur

A

LOWER EO

43
Q

The property of the surface of a liquid that allows it to resist an external force, due to the cohesive nature of its molecules.

A

SURFACE TENSION

44
Q

It is defined as a material that can reduce the surface tension of water. at lower concentrations.

A

SURFACTANT

45
Q

It may enhance or retard the drug absorption, which depends upon the chemical nature of surfactant, its concentration, its effect on biological membrane, and micelle formation.

A

SURFACE AGENT

46
Q

At lower concentrations, the surfactants _____

A

ENHANCE THE ABSORPTION RATE

47
Q

Molecular aggregates which entrap the drug molecule in their hydrophobic core, and result in the retardation of the rate of absorption.

A

MICELLE

48
Q

Classification of Surface-active agents

A

ANIONIC SURFACTANTS
CATIONIC SURFACTANTS
NONIONIC SURFACTANTS
AMPHOTERIC SURFACTANTS

49
Q

Examples of Anionic Surfactants

A
  • ORDINARY SOAPS
  • SALTS OF BILE ACIDS
  • SALTS OF THE SULPHATE OR PHOSPHATE ESTERS OF ALCOHOLS
  • SALTS OF SULPHONIC ACID
50
Q

Examples of Cationic Surfactants

A
  • HIGH MOLECULAR WEIGHT ALIPHATIC AMINES
  • QUATERNARY AMMONIUM DERIVATIVES
51
Q

Examples of Nonionic Surfactants

A
  • POLYETHYLENE ETHERS
  • GLYCOL ESTERS OF FATTY ACIDS
52
Q

Application of Surface Tension

A

BACTERICIDAL ACTIVITY
ANTHELMINTIC ACTIVITY OF HYDROXY RESORCINOL

53
Q

It results from a donor-acceptor mechanism or Lewis acid-base reaction.

A

COMPLEXES OR COORDINATION

54
Q

The compounds that are obtained by donating electrons to metal ions with the formation of ring structures.

A

CHELATES

55
Q

The compounds that are capable of forming a ring structure with metal atoms.

A

LIGANDS

56
Q

A ligand that has a single basic group capable of bonding to the metal ion and is an UNIDENTATE LIGAND

A

AMMONIA

57
Q

A ligand having more than one accessible basic binding site

A

MULTIDENTATE

58
Q

It is a BIDENTATE ligand form, and chelates with Cu (II)

A

ETHYLENEDIAMINE

59
Q

An antidote that chelates iron in iron poisoning

A

DEFEROXAMINE

60
Q

Used in treatment of lead poisoning

A

DIMERCAPROL

61
Q

Used to treat Anemia

A

VITAMIN B12

62
Q

A naturally-occuring cobalt complex

A

VITAMIN B12

63
Q

Used in the treatment of Copper and Wilson’s disease

A

L-PENICILLAMINE

64
Q

Different ways atom can flex or bend

A

CONFORMATIONAL ISOMERS

65
Q

Different arrangements in the space for atoms or groups in single bonds.

A

CONFORMATIONS

66
Q

Two ways conformational isomers are presented:

A

SAWHORSE FORMULA
NEWMAN’S PROJECTION FORMULA

67
Q

It shows how the spatial orientation of all C-H bonds is arranged at an angle.

A

SAWHORSE FORMULA

68
Q

The two carbon atoms are represented by a circle and a carbon-carbon bond is viewed along its axis.

A

NEWMAN’S PROJECTION FORMULA

69
Q

Line representation towards the center of the circle represents the bonds attached to the FRONT CARBON

A

NEWMAN’s PROJECTION FORMULA

70
Q

Lines going to the edge of the circle are used to view the bonds attached to the REAR CARBON

A

NEWMAN’s PROJECTION FORMULA

71
Q

It has a higher energy than the anticonformation (staggered) due to stearic chuchu

A

GAUCHE CONFORMATION

72
Q

HIGH ENERGY MOLECULE - LEAST STABLE
LOW ENERGY MOLECULE - MORE STABLE

A
73
Q

It has lower energy (the most stable)

A

ANTICONFORMATION / STAGGERED

74
Q

Energy and Stability is inversely proportional

A
75
Q

Most stable to least stable

A
  1. STAGGERED CONFORMATION
  2. GAUCHE
  3. ECLIPSED CONFORMATION
  4. ECLIPSED (A)
76
Q

Are configurational isomers which have the ability to rotate plane-polarized light clockwise or counterclockwise.

A

OPTICAL ISOMERS

77
Q

Categories of Optical Isomers

A

ENANTIOMERS
DIASTEREOMERS

78
Q

Are mirror images, non superimposable

A

ENANTIOMERS

79
Q

Are a pair of molecules that exist in two forms that are mirror images of one another but cannot be superimposed one upon the other.

A

ENANTIOMERS

80
Q

non-mirror images, non-superimposable

A

DIASTEREOMERS

81
Q

Defined as compounds which have the same molecular formula and sequence of bonded elements but which are non-superimposable, non-mirror images

A

DIASTEREOMERS

82
Q

It is of vital importance to the medicinal chemists because the biological characteristics of isosteres appear to be similar; more frequently than physical or chemical characteristics.

A

ISOSTERISM

83
Q

It is used to reduce toxicity, change bioavailability, or modify the activity of the lead compound, and may alter the metabolism of the lead.

A

BIOISOSTERISM

84
Q

Two types of Bioisosteres

A

CLASSICAL
NONCLASSICAL

85
Q

They have similarities in shape and electronic configuration of atoms, groups, and molecules, which they replace.

A

CLASSICAL BIOISOSTERES

86
Q

They do not obey the steric and electronic definition of classical isosteres. Also, they do not have the same number of atoms as replacements.

A

NONCLASSICAL BIOISOSTERES