Common Excipients in Formulations

Question 1

Recall Lipinski’s Rule of 5.

Answer 1

• =< 5 H bond DONORS
• =< 10 H bond ACCEPTORS
• < 500 Da (< 300Da for hydrophilic, < 1 kDa for lipophilic)
• Log P < 5
• Unionised

Use Lipinski’s Rule as a guide rather than a hard and fast rule for drugs/substances. Strategy is to look at the overall molecule based on the Lipinski’s rule, see how many it fulfills and make a decision on whether it passes through BBB.

Question 2

Acetic and citric acids

Answer 2

pH adjustment/ buffer

Question 3

Sodium hydroxide

Answer 3

pH adjustment

Question 4

Hydrochloric acid

Answer 4

pH adjustment

Question 5

Sodium borate

Answer 5

pH adjustment

Question 6

Boric acid

Answer 6

pH adjustment

Question 7

Sodium acetate, citrate, and phosphates

Answer 7

Buffer

Question 8

Potassium phosphate

Answer 8

Buffer

Question 9

Edetate disodium

Answer 9

Metal chelator / Preservative enhancer

Question 10

Benzalkonium chloride

Answer 10

Preservative (known effect on cillia)

Question 11

Benzethonium chloride

Answer 11

Preservative

Question 12

Benzyl alcohol

Answer 12

Preservative

Question 13

Chlorhexidine (di)gluconate

Answer 13

Preservative

Question 14

Chlorobutanol

Answer 14

Preservative (known effect on cillia)

Question 15

Methylparaben

Answer 15

Preservative (known effect on cilia)

Question 16

Phenylethyl alcohol

Answer 16

Preservative

Question 17

Propylparaben

Answer 17

Preservative (known effect on cilia)

Question 18

Potassium chloride

Answer 18

Tonicity adjustment

Question 19

Sodium chloride

Answer 19

Tonicity adjustment

Question 20

Me-OH-Pr cellulose (Hydroxypropyl Methylcellulose)

Answer 20

Viscosity adjustment

Question 21

Celluloses
e.g. Sodium Carboxymethyl Cellulose (Na CMC), Microcrysalline Cellulose, Carboxymethylcellulose (CMC), Hydroxypropyl Methyl Cellulose (HPMC)

Answer 21

Viscosity adjustment
Transdermal: viscosity adjustment, matrix polymer

Question 22

Ethanol

Answer 22

Solvent
Transdermal: solvent, permeation enhancer

Question 23

Glycerin

Answer 23

Solvent/ tonicity adjustment

Question 24

Glycerol

Answer 24

Solvent/ tonicity adjustment

Question 25

Glycine

Answer 25

Solvent/ tonicity adjustment

Question 26

PEG

Answer 26

Solvent

Question 27

Polyethene glycol

Answer 27

Solvent

Question 28

Glyceryl dioleate

Answer 28

Solvent/ surfactant

Question 29

Glyceryl monoleate

Answer 29

Surfactant Transdermal: permeation enhancer, bioadhesive, sustained release agent

Question 30

Lecithin

Answer 30

Surfactant

Question 31

Polysorbate 20 & 80

Answer 31

Surfactant

Question 32

Tyloxapol

Answer 32

Surfactant

Question 33

Menthol

Answer 33

Flavouring agent

Question 34

Saccharin sodium

Answer 34

Flavouring agent (sweetener)

Question 35

Sorbitol

Answer 35

Flavouring agent (sweetener)

Question 36

What is Lipinski's Rule of 5 for **CNS Delivery**?

Answer 36

* <3 H bond DONORS * <7 H bond ACCEPTORS * < 450 Da * Log P 1-3 * Unionised ## Footnote Use Lipinski's Rule as a guide rather than a hard and fast rule for drugs/substances. Strategy is to look at the overall molecule based on the Lipinski's rule, see how many it fulfills and make a decision on whether it passes through BBB.

Question 37

Cyclodextrin

Answer 37

Transdermal: permeation enhancer

Question 38

What is Lipinski's Rule of 5 for **Transdermal Delivery**?

Answer 38

* =< 5 H bond DONORS * =< 10 H bond ACCEPTORS * < 500 Da * Log P 1-3 * Unionised ## Footnote Use Lipinski's Rule as a guide rather than a hard and fast rule for drugs/substances. Strategy is to look at the overall molecule based on the Lipinski's rule, see how many it fulfills and make a decision on whether it passes through BBB.

Question 39

Propylene glycol

Answer 39

Transdermal: solvent, permeation enhancer

Question 40

Hyaluronate sodium

Answer 40

Transdermal: viscosity adjustment, humectant, matrix polymer

Question 41

Calcium alginate

Answer 41

Transdermal: viscosity adjustment, adhesive, matrix polymer

Question 42

Carbomer

Answer 42

Transdermal: viscosity adjustment, adhesive

Question 43

Poly(methyl vinyl ether/ maleic anhydride)

Answer 43

Transdermal: viscosity adjustment, adhesive

Question 44

Polyester

Answer 44

Transdermal: polymer matrix in **backing layer**

Question 45

Silicone

Answer 45

Transdermal: adhesive

Question 46

Ascorbyl Palmitate

Answer 46

Transdermal: permeation enhancer

Question 47

Phenol

Answer 47

Preservative

Question 48

Thiomersal

Answer 48

Preservative

Question 49

Mannitol

Answer 49

Tonicity adjustment / cryoprotectant ## Footnote Cryoprotectant: for injection solutions that are frozen, to maintain integrity of molecules