exam 1 lecture 1 Flashcards

1
Q

Types of liquid dosage forms

A

Solution: homogenous molecular dispersion (nothing suspended - see through)
Emulsion: oil in water, water in oil (liquid drops suspending)
Suspension: solid in water or oil (solid suspended)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Advantages of solutions

A

Homogenous – no problems of content uniformity
Easy to manufacture
Good bioavailability –> already dissolved molecular level
Disadvantage: more reactive/ less stable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

components of solution dosage form

A

API
solvent: water, vegetable oil
co-solvent: ethanol, glycerin, propylene glycol
buffering agent: maintain pH
preservative: maintain stablility
antioxiadant/chelating agent
flavor: sucrose/sorbitol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

buffer principle

A

a solution of a weak acid and a salt of its conjugate base
weak acid removes base: HA+ + OH- –> H2O + A-
salt removes added acid: A- + H3O+ –> HA + H2O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

buffer equations

A

henderson hassalback
pH = pKa + log (A-/HA)
b = 2.3C * ((Ka[H3O+])/(Ka + [H3O+])^2))

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

selection of pH

A

select pKa close to pH bc minimize buffering capacity and allows for most stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

if cannot match pH of solution to pH of body fluid

A

minimize irritation with parenteral, opthalmic, or nasal dosage forms
adjust pH to be the same as pH of body fluid (7.4)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

antimicrobial preservatives

A

purpose: protect patient from pathogens + maintain potency and stability
MOA:
preservative absorb to bacterial membrane and disrupt the membrane. membrane is lipophilic and has net negative surface charge
absorption due to lipid solubility +electrostatic interactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

bacterial content allowed in dosage forms

A

ampules: must be sterile, single dose, no perservative
multiple dose vials: must be sterile, up to 10 doses, need preservative.
opthalmic solutions: must be sterile, need preservatives in multiple dose container
oral liquids: not sterile, but no pathogens
oral solids: less likely to have bacteria bc no water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

ideal preservatives

A

effective in low concentrations against wide variety of organisms
soluble in formulation
nontoxic
stable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

pharmaceutical preservatives

A

alcohols, acids, esters, quaternary ammonia compounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

factors affecting preservative action

A

pH: unionized species of weak acids are effective as a preservative
complex formation: only uncomplexed (free) preservative is active
absorption by solids: only unabsorbed preservative is active
chemical stability: consider shelf-life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

alcohols

A

ethanol: limited to oral products bc overtime conc. drops
benzyl alcohol: not orally used, water soluble, stable over wide pH range
chlorobutanol: not orally used

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

acids

A

only active in unionized form (lipid soluble)
benzioc acid (pka - 4.2) –> oral products
sorbic acid (pka 4.8) –> oral products, molds + yeast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

esters

A

widely used orally
hydrolyzed rapidly at pH above 7
most lipophilic: propyl + butyl paraben
less lipophilic: methyl + ethyl paraben
low solubility = problem
can cause skin sensitization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

quaternary ammonium compounds

A

benzalkonium chloride, cetyltrimethylammonium chloride
widely used in opthalmic –> very water soluble + fast killing

17
Q

oxidation

A

oxidation: main degradation pathway of pharmaceuticals
initiated by heat, light, peroxides, metals
drug substances are less stable in aqueous form
acid-base reactions, acid/base catalysis, oxidation or reduction may occur

18
Q

auto-oxidation

A

automatic reaction w/ oxygen w/o drastic external interference

19
Q

antioxidants

A

free-radical scavengers
reducing agents
chelating agents

20
Q

free-radical scavengers

A

retardant - delay oxidation by rapidly reacting with free radicals
propyl, octyl, dodecyl esters of gallic acids
butylated hydroxyanisole(BHA), butylated hydroxytoluene (BHT)
tocopherols, Vit. E

21
Q

reducing agents (antioxidant)

A

have lower redox potentials than drugs –> more readily oxidized
sodium bisulfite
ascorbic acid
thiols

22
Q

chelating agents (antioxidants)

A

acts indirectly
antioxidant synergists
little antioxidant effect themselves
remove trace metals
citric acid + EDTA