Pharmaceutics

Question 1

Hydrophobic Solutes

Answer 1

Cl, F, CH2, CH3, OCH2CH3

Question 2

Hydrophilic Solutes

Answer 2

OH, COO-, NH3+

Question 3

What is the flickering cluster model?

Answer 3

Involves clusters of H-bonded “ice-like” water within pools of unbound (i.e. no H-bonding) water.

Question 4

What’s a Real solution?

Answer 4

Interactions occur between dissolved solutes which reduce the effective concentration

Question 5

What’s an ideal solution?

Answer 5

There are no interactions between dissolved solutes.

Question 6

Equation for activity coefficient

Answer 6

Activity/Concentration

Question 7

Weakly Acidic Drugs Solubility Equation

Answer 7

pH=pKa + Log S-So/So

Question 8

Weakly Basic Drugs Solubility Equation

Answer 8

pH=pKa + Log So/S-So

Question 9

What’s the isoelectric point?

Answer 9

Isoelectric point is the pH at which the drug carries no net electric charge.

Question 10

What’s Partitioning?

Answer 10

Partitioning is the distribution (or moving) of a substance between two miscible phases.

Question 11

Partition coefficient equation

Answer 11

Co/Cw

Co=Conc. in organic phase

Cw=Conc. in aqueous phase

Question 12

Partition of weak acid equation

Answer 12

Log (P/Papp -1) = pH-pKa

Question 13

Partition of a weak base equation

Answer 13

Log (P/Papp -1)=pKa-pH

Question 14

What does polydisperse mean?

Answer 14

Polymers exist within a range of different molecular weights

Question 15

Methods of determining polymer molecular weight?

Answer 15

• Number average molecular weight (Mn)
• Weight average molecular weight (Mw)

A viscosity average molecular weight (Mv)

Mn>Mv>Mw

Question 16

Techniques to characterise polymers

Answer 16

• Light scattering techniques
• Viscosity techniques
• Analytical ultracentrifugation
• Gel electrophoresis
• NMR

Question 17

Water soluble polymers

Answer 17

Able to:

Increase solvent viscosity

Swell

Therefore good suspending agents

Question 18

Velocity of penetration

Answer 18

S=kM-A

k and A constant

M-Polymer molecular weight

Question 19

Viscosity and molecular weight

Answer 19

n=KMa

k and a are constants

M-Molecular weight

Question 20

Gels

Answer 20

Type 1: Irreversible eg contact lenses

Type 2: Heat reversible eg agar

Question 21

Serendipituous

Answer 21

A chance discovery eg alginate for heartburn, penicillin etc

Question 22

Gavison Excipients

Answer 22

Carbomer: Suspending agent

Parahydroxybenzoate: Antimicrobial preservative

Sodium Saccharin: Sweetener

Sodium Hydroxide: pH adjuster (due to acidic parahydroxybenzoate)

Question 23

Containers

Answer 23

Glass

High-density polyethylene

Polyethylene terephthalate

(Greater potential for parabens absorption as you go down)

Question 24

Why coat tablets?

Answer 24

Protect from environement

Mask a taste

Easier to swallow

Identification

Question 25

Film Coating

Answer 25

Polymer 10%

Solvent 90%

Drying process removes solvent and leaves behind film.

Cellulose and Cellulose ethers (Immediate release)

Question 26

Enteric Coating

Answer 26

Cellulose acetate phthalate

Methacrylic acid copolymers

Omeprazole:

Gelatin capsule dissolves, enteric coat on granules doesnt

Granules can pass through pyloric sphincter

Question 27

MUPS

Answer 27

Multiple Unit Pellet System

Enteric coated particles compressed into a tablet

Mathacrylic acid copolymers