Lab 4

Question 1

name 7 reasons for formulating drugs as suspensions

Answer 1

-water insoluble drugs can be administered in liquid form

-if the drug is chemically unstable in solution but stable in suspension

-if the patient prefers liquids over solids

-dosage flexibility for infants, children, and the elderly

-suspension helps improve the taste of some poor-tasting drugs

-liquid preparation is suitable dosage form for IM and SUBQ injections

-unstable drugs to be reconstituted from powders

Question 2

true or false

insoluble drugs generally do not impart taste

Answer 2

true

Question 3

the _______ nature of a drug determines the degree of wettability of the drug

Answer 3

hydrophobic/nonpolar nature

Question 4

drugs containing ___ and/or ____ tend to be hydrophobic (nonpolar)

Answer 4

alkyl groups and/or aromatic rings

Question 5

some water insoluble drugs _____ within the water while others _____

Answer 5

some drugs may form large porous clumps WITHIN the liquid

others remain on the surface and become attached to the upper part of the contaienr

Question 6

when it’s determined that a wetting agent is needed for an insoluble drug, what should you do first?

Answer 6

check if any of the excipients included in the formulation can be used for wetting

if not, choose a suitable wetting agent

Question 7

name 3 suitable wetting agents

Answer 7

glycerin, ethanol, propylene glycol

Question 8

in what concentration should wetting agents be used?

Answer 8

the LOWEST CONCENTRATION that provides adequate wetting

Question 9

suspending agents are used for ___ enhancing properties

Answer 9

viscosity

Question 10

true or false

suspending agents may be charged in solution

Answer 10

true

Question 11

suspending agents may have ___ properties

Answer 11

flocculating (forming readily dispersible aggregates)

Question 12

the selection of suspending agents depends on what 4 things?

Answer 12

-the drug properties
-properties of the suspending agent
-presence of other suspending agents
-properties of the suspension (pH, storage)

Question 13

the amount of suspending agent used in any given formulation depends on what?

Answer 13

the volume of the vehicle being thickened

Question 14

true or false

the amount of suspending agent used in any given formulation varies with the amount of drug in the preparation

Answer 14

FALSE – only varies with the volume of the medium being thickened

Question 15

explain what Co-trimoxazole is

Answer 15

a combo of trimethoprim and sulfamethoxazole in a 1:5 (fixed) ratio

commonly prescribed to treat UTIs

Question 16

Sulfamethoxazole is a ___ drug

Answer 16

sulfonamide

Question 17

explain the physical properties of sulfamethoxazole

Answer 17

tasteless, odorless, almost white crystalline powder

Question 18

Give the chemical properties of sulfamethoxazole.

include:
pka
ionized form
aqueous solubility

Answer 18

pka = 6.1
ionized form = cationic
aqueous solubility - slightly less than 350mg/100mL at pH range 5.5-7.4

Question 19

true or false

the primary amine in sulfamethoxazole can ionize and form ionic interactions

Answer 19

true

Question 20

an ionized primary amine can act as a strong what?

Answer 20

hydrogen bond donor

Question 21

explain the significance of the aromatic ring in the structure of sulfamethoxazole

Answer 21

increases the hydrophobic character and affects solubility

Question 22

________ reactions have been observed with sulfamethoxazole

Answer 22

hypersensitivity
-drug fever, skin allergies, and photosensitivity

Question 23

what is trimethoprim?

Answer 23

an antibacterial agent used in combination with other anti-infectives.

Question 24

trimethoprim eliminates bacteria that cause what?

Answer 24

urinary tract infections

Question 25

trimethoprim is used in combination with other drugs to treat certain types of ___ and ____

Answer 25

pneumonia and traveler’s diarrhea

Question 26

is Co-trimoxazole chemically stable in the presence of sucrose?

Answer 26

yes

Question 27

what is the pH range of Co-trimoxazole suspension

Answer 27

5.5-7

Question 28

true or false

preservatives must be added to Co-trimoxazole suspension if it is to be stored at room temperature

Answer 28

TRUE

to contain/prevent microbial growth

when NO preservative is added, the suspension has to be stored in the fridge and the duration of storage must be reduced

Question 29

explain the preservative effects of simple syrup

Answer 29

simple syrup is self preserving, but the ingredients contain some moisture so the product is able to absorb moisture (hygroscopic)

Question 30

When a high sucrose content is undesirable, what happens?

Answer 30

other low or non calorie, non-glycemic sugars or artifical sweeteners are used to replace the sucrose

Question 31

saccharin is a _____ sweetener

Answer 31

artificial

Question 32

to reduce the after taste of saccharin, what is sometimes added?

Answer 32

some sucrose or other natural sugars

Question 33

true or false

sucrose is not a natural sweetener

Answer 33

false – it is

Question 34

when sucrose content is reduced in suspensions, what is a concern?

Answer 34

reduction in viscosity

thus, a viscosity enhancer/suspending agent must be added to the preparation

Question 35

Tragacanth is effective and stable at what pH?

Answer 35

5.5-7

Question 36

true or false

Co-trimoxazole is compatible with tragacanth

Answer 36

true

Question 37

is tragacanth a natural or artifical product?

Answer 37

natural.

for all natural products, microbial contamination is a concern. therefore, a preservative must be added

Question 38

what is the function of tragacanth

Answer 38

a suspending agent

also has flocculating and viscosity enhancing properties

Question 39

of the ingredients used in the Co-trimoxazole suspension, which is VERY hydrophilic?

what should you do with this information?

Answer 39

tragacanth is very hydrophilic

therefore, it should NOT be added directly to water. To prevent lumping and fish eyes, 1st prepare a slurry in a non aqueous substance or first blend with the dry ingredients