introduction to medicinal products part 3

Question 1

what is a solution?

Answer 1

mixing two or more substances forming a single phase that are similar molecularly

Question 2

what is one property about solutions?

Answer 2

they are clear

Question 3

why are most pharmaceutical solutions water based?

Answer 3

water isn’t toxic and is cheap

Question 4

why is tap water not used for pharmaceutical solutions?

Answer 4

may contain substances that will effect the solubility and stability of the drug

Question 5

how is water purified?

Answer 5

distillation, ion exchange or reverse osmosis

Question 6

what routes are solutions delivered?

Answer 6

oral, ocular, otic, nasal, pulmonary route, parenteral, topical, rectal

Question 7

why do the requirements of solutions vary?

Answer 7

different routes of administration

Question 8

what are the requirements for oral solutions?

Answer 8

palatable and viscosity should allow for pouring of the solution

Question 9

requirements for topical solutions?

Answer 9

easy to transfer from container, should be able to attach to the surface without difficulty when removing

Question 10

what are the requirements for ocular?

Answer 10

sterile, ph has to be close to 7.4 (ph of tears) so no discomfort is created, isotonic with tears so it doesn’t cause irritation for the eye or discomfort, appropriate viscosity for the eye

Question 11

what ph can an eye tolerate?

Answer 11

3-9

Question 12

why are non-aqueous solvents not used for all routes of administration?

Answer 12

unpalatable, toxic and doesn’t mix with other liquids.

Question 13

what routes of administration are non-aqueous solvents used for?

Answer 13

intramuscular and topic

Question 14

examples of non-aqueous solvents used?

Answer 14

esters and vegetable oil

Question 15

what instances can non-aqueous solvents be used in?

Answer 15

when API is unstable and not soluble in aqueous solutions

Question 16

what are the requirements for nasal solutions?

Answer 16

isotonic to fluids in the nose, ph 5.5-6.5, appropriate viscosity which is similar to mucus, taste masked in case its swallowed

Question 17

what are the requirements for parenteral solutions?

Answer 17

sterile, isotonic when given in large volumes, appropriate ph to physiological ph so tissue necrosis doesn’t happen

Question 18

what are the excipients used in solutions?

Answer 18

flavourings, colouring agents, antioxidants, ph adjusters, viscosity enhancers, isotonicity adjusters, antimicrobial adjusters, antimicrobial preservatives, solubility enhancers

Question 19

what is the purpose of adding flavourings?

Answer 19

to make the solution more desirable for the patient to take

Question 20

examples of flavourings used?

Answer 20

methanol, orange oil, lemon oil

Question 21

what is the purpose of colourings?

Answer 21

makes the medicine more attractive to the eye (organoleptic properties) and should match the flavourings added

Question 22

what is the purpose of atioxidants?

Answer 22

for stability

Question 23

examples of antioxidants used?

Answer 23

sodium bisulphate and sodium sulphite

Question 24

purpose of ph adjusters?

Answer 24

added to make sure the ph of medicine doesn’t cause irritation or discomfort or necrosis

Question 25

examples of ph adjusters?

Answer 25

citric acid, buffers, sodium hydroxide

Question 26

what are viscosity enhancers for?

Answer 26

to make solutions easier to handle and makes sure they stay on the site of administration for however long its required

Question 27

examples of viscosity enhancers?

Answer 27

hydroxymethyl cellulose

Question 28

what is isotonicity enhancers used for?

Answer 28

to make sure the solution is isotonic

Question 29

what are antimicrobial preservatives used for?

Answer 29

they don't allow the growth of microorganisms

Question 30

examples of antimicrobial preservatives?

Answer 30

parabens, benzalkonium chloride

Question 31

why is benzalkonium chloride not used nebulizer solutions but is used in oral solutions?

Answer 31

because it can cause bronchoconstriction

Question 32

what are solubility enhancers for?

Answer 32

to keep the solubility of the drug constant and to improve it

Question 33

what are suspensions?

Answer 33

solid particles within liquid because the solid doesn't dissolve enough in the liquid

Question 34

why do many drugs cause challengers when it comes to formulation?

Answer 34

they have low aqueous solubility because they fit in hydrophobic pockets of a receptor to actually work

Question 35

what does a good suspension include?

Answer 35

the solid particles of the same size are evenly distributed in the liquid and stay like that for a long time so every dose of drug is the same therefore has the same effect on the patient

Question 36

what is sedimentation?

Answer 36

particles being dragged downwards due to gravity pull

Question 37

why is sedimentation a problem in suspensions?

Answer 37

solid particles aren't evenly distributed so same dosage won't be received by each patient

Question 38

how to reduce the rate of sedimentation?

Answer 38

reducing the size of solid particles, increase viscosity of liquid, reduce density difference between particle and liquid

Question 39

what instances can you and can't you redisperse a medicine?

Answer 39

sedimentation- can shake to make a uniform suspension caking- can't redisperse even after shaking

Question 40

what excipients are present in suspensions?

Answer 40

antimicrobial preservatives, buffers, chemical stabiliser, suspension agents, viscosity modifiers, flocculation modifier

Question 41

what are buffers for?

Answer 41

keeps ph within a narrow limit

Question 42

examples of chemical stabilizer?

Answer 42

ascorbic acid (vitamin C), EDTA

Question 43

what are suspending density and viscosity modifiers for?

Answer 43

increasing density, reduces the rate of sedimentation

Question 44

examples of suspending density and viscosity modifiers?

Answer 44

methylcellulose and hydroxypropyl cellulose are cellulose ethers

Question 45

what are flocculation modifiers for?

Answer 45

reduces the number of floccules forming which are loose particles

Question 46

why are suspension sometimes used for medicines for children over solutions?

Answer 46

because the taste of the drug isn't as strong

Question 47

how does ph control drugs?

Answer 47

effects the amount of ionisation which in turn effects solubilit

Question 48

what percentage of drugs are weak bases?

Answer 48

75 percent

Question 49

what is the purpose of a buffer?

Answer 49

so drug doesn't cause irritation or necrosis at site of application ensures stability of API and excipients used ensure solubility in solutions to subdue solubility in suspenssions

Question 50

draw a graph on how percentage ionized, percentage of solubility differ between weak bases and weak acids

Answer 50

refer to slide 19 introduction to medicinal products part 3 ppt

Question 51

what equation is used to calculate ionization of a weak acid?

Answer 51

pH= pK_a + (log_10 ([A^− ] )/[HA])

Question 52

what equation is used to calculate ionization of a weak base?

Answer 52

pH= pK_a + (log_10 ([𝐵] )/[〖𝐵𝐻〗^+ ])

Question 53

what does a buffer do in a solution?

Answer 53

maintains the ph when small amounts of acid or alkali is added

Question 54

example of a buffer?

Answer 54

acetic acid and its salt

Question 55

what is the name given for a buffer to handle changes in ph?

Answer 55

buffer capacity (β)

Question 56

what is β equal to?

Answer 56

the moles of H+ needed to change 1 litre of buffer by 1 ph unit

Question 57

when does buffer capacity increase?

Answer 57

when concentrations of substances increase

Question 58

when is buffer capacity the greatest?

Answer 58

when ph=pKa of acid

Question 59

examples of buffer solutions?

Answer 59

acetate, citrate and phosphate buffer

Question 60

when can absorption occur in the gastrointestinal tract?

Answer 60

when drug is in solution

Question 61

what are the biopharmaceutical considerations of drugs diagram?

Answer 61

slide 23 ppt introduction to medicinal products part 3

Question 62

what order of bioavailability do drugs follow?

Answer 62

aqueous solutions > aqueous suspensions > solid dosage forms

Question 63

which step does solution administration bypass?

Answer 63

disintegration