Drug Stereochemistry

Question 1

there are 3 types of pharmaceutical agents

Answer 1

1. synthetic
2. natural
3. semi-synthetic (partial synthesis)

Question 2

1/3 of synthetic drugs are chiral and of that only 12% are

Answer 2

single enantiomers

Question 3

what is a chiral molecule

Answer 3

a chiral molecule possesses a asymmetric carbon centre capable of existing in more than one form or entantiomers

Question 4

what is an enantiomer

Answer 4

an enantiomer (or optical isomer) is one of two sterioisomers that are mirror images of each other and are non-superimposable

Question 5

Enantiomers of a drug can be (5 things)

Answer 5

• active
• inactive
• have different pharmacological effect
• can be toxic
• have unknown effect

Question 6

what is an example of a single enatiomeric drug

Answer 6

augmentin

lipitor

paxil

Question 7

the processes of active transport, protein binding and metabolism depend highly on (3 things) that impact reaction rates in different enatiomers

Answer 7

• chiral receptor channels
• transport molecules
• enzymes

Question 8

drug chirality does not impact

Answer 8

absorption, distribution or elimination

Question 9

more active isomer

Answer 9

entomer

Question 10

less active isomer

Answer 10

distomer

Question 11

identicial molecular formulae

differ in nautre and sequence of bonding

Answer 11

isomer

Question 12

what are 2 types of isomers

Answer 12

• constitutionally different
  
  • impact nature and sequence of binding
• stereoisomers
  
  • differ only in arrangement of atoms in space

Question 13

enatiomers

Answer 13

are not superimposable

e.g. lactic acid

Question 14

what atoms can act as asymmetrical centres and form chiral molecules

Answer 14

• carbon
• nitrogen
• phosphorus
• sulfur

Question 15

how is optical activity of a molecule measured

Answer 15

• using a polarimeter

Question 16

how does a polarimeter work?

Answer 16

• when polarized lisght is passed through a solution of organic molecules the plan of polarized light is rotated
• polarized light is passed through the sample to an anlayzer equipped with another polarizer
• the amount of rotation (alpha) is measured and reported in degrees

Question 17

compounds that can rotate a plane of polarized light are

Answer 17

optically active

Question 18

molecules which rotate to the right or clockwise are

Answer 18

• (+) Dextrorotatory

Question 19

molecules which rotate to the left, or counterclockwise are

Answer 19

(-) levorotatory

Question 20

specific rotation is defined as

Answer 20

the observed rotation when light of 589 nm is used (sodium D line), with a sample path of 1 decimeter and sample concentration of 1 g/ml

Question 21

how is specific rotation calculated