Solutions Flashcards
define solutions vs suspensions vs emulsions
solutions - CLEAR liquid preparations w 1 or more agents DISSOLVED in a vehicle
suspensions = solid in liquid dispersions
emulsions - liquid in liquid dispersion
true or false
suspensions and emulsions are not homogenous, while solutions are
TRUE
as mentioned, solutions are homogenous - a mixture of 1 or more solutes dissolved in a solvent.
this dissolution is at the ____ or ____ level
molecular or ionic
true or false
solutions are not thermodynamically stable and is a 1 phase system
FALSE - they are 1 phase systems, but ARE thermodynamically stable
true or false
a solution can only be a solid homogenously dissolved in a liquid
FALSE
can be a combination of solids, liquids, and/or gasses
HOWEVER, for PHARMACEUTICAL SOLUTIONS — limited to a solid or liquid homogenously dissolved in a LIQUID SOLVENT
when looking at a compounding procedure, what is 1 way to tell that you are making a solution by looking at the instructions?
will say, “completely dissolved” in vehicle
true or false
a disadvantage of solutions is that they are not immediately available for absorption
FALSE - they are
no disintegration or dissolution needed like in the case of a tablet
true or false
solutions can be used via various routes of absorption, and this is an advantage
TRUE
ie - oral, topical, rectal, ophthalmic, otic, etc
which are more stable - solids or solutions
SOLIDS
thus, low stability is an issue with solutions
true or false
a disadvantage of solutions is that you need to mask any unpleasant taste
TRUE
bc when you drink it it spreads all over the tongue — suspensions and capsules are better for drugs that taste bad
what is a disadvantage of solutions when compared to unit dose forms
they are less accurate in their dosing
true or false
solutions are homogenous and can give a uniform dose
TRUE
true or false
solutions are hard to administer in patients who have difficulty swallowing, and this is a disadvantage
FALSE
easier to administer - ie - pediatrics who cant swallow pills
true or false
it is difficult to adjust the dose of solutions and this is a disadvantage
FALSE - easy to adjust and this is an advantag3e
do solutions need to be shaken before use?
NO
they are a homogenous, thermodynamically stable, 1 phase system
solutions are a ____ phase system
1
which gives faster absorption***
solutions or emulsions
SOLUTIONS ALWAYS
suspensions and emulsions need to still dissolve in the gastric fluid
true or false
a disadvantage of solutions is that they are difficult to handle, package, transport and store
TRUE
they are bulkier and heavier than tablets
________ may limit the use of solutionS
INTRINSIC SOLUBILITY
ie - if drug A is insoluble in water, we cannot make a stable solution
true or false
neither disintegration NOR dissolution is needed for solutions to absorb
true
explain how the USP defines approximate solubility using descriptive terms**
“parts of solventrequired for 1 part of solute”
ie - how many mL needed to dissolve 1 gram of solute
which is more soluble in water
Drug A: 1-10
Drug B: 30-100
“parts of solvent to dissolve 1 part solvent”
so higher the number = less soluble
DRUG A IS MORE SOLUBLE. less mL of solvent needed to dissolve the drug
“the solubility of a drug is the expression of quantity of a drug that can be maintained in solution at a given ___ and ___ and is usually expressed as….”
temp and pressure
mL solvent needed to dissolve 1 g of drug
name 4 types of aqueous solutions
syrups
aromatic waters
mucilages
aqueous acids
ALL aqueous solutions (syrups, aromatic waters, mucilages, aqueous acids), have what in common
WATER as the major vehicle
___ or ___ water should always be used when preparing pharmaceutical solutions
distilled or purified
syrups are a concentrated or nearly saturated solution of ____ in water
____% ____
less than ____10%____
SUCROSE
60-80% sucrose
less than 10% alcohol (to preserve free water in the syrup)
explain what aromatic waters are
saturated solutions of volatile oils in water - used to provide plesant flavor/smell
TYPE OF AQUEOUS SOLUTION
Explain what mucilages are
type of aqueous solution
THICK AND VISCOUS - vegetable gums dispersed in water
used as suspending or thickening agents
explain what aqueous acids are
dilute aqueous solutions of acids (usually less than 10%)
TYPE OF AQUEOUS SOLUTION
not dispensed - used as stock solution for compounding
*** syrup, USP contains _____g of sucrose and ____mL of water in EACH LITER OF SYRUP
thus, how many mL can be occupied by sucrose powder?
850g and 463mL water
1000mL - 463mL = 537mL of 1000mL can be occupied by sucrose
2 purposes of syrup USP
-sweetening agent
-vehicle for other syrups
true or false
Syrup, USP needs excipients to preserve it
FALSE
it is self preserving with miminal chance of crystallization
HOWEVER, DILUTED sucrose solutions are good for microorganism growth, so if the sucrose cons is below 85% w/v, SHOULD ADD ANOTHER PRESERVATIVE
As mentioned, Syrup, USP is self preserving.
however, there is 463mL of water in 1000mL of Syrup, USP
how is this water being preserved?
the high sucrose concentration
**Alcohol content of “Alcohol, USP”
95%
NOT 100%!!!!!!!
non aqueous solutions are solutions that contain solvents other than water
name 2 frequently used non aqueous solvents
alcohol OR a binary mixture containing alcogol
name 4 non aqueous solutions AND THEIR ALCOHOL CONTENTS*****
Elixir - 5-40%
spirits/essences - 62-85%
tinctures - 15-80%
KEY WORD for tinctures
prepared from VEGETABLE OR CHEMICAL SUBSTANCES BY MACERATION OR PERCOLATION
_______are alcoholic or hydroalcoholic solutions of volatile substances
spirits or essences
compared with syrups, elixirs are _____ sweet and ____ viscous
less sweet and less viscous (bc lower proportion of sugar)
which are better at masking the taste of medicinal substances - syrups or elixirs?
syrups
which is better to maintain BOTH water soluble and alcohol soluble components in solution- elixirs or aqueous syrups
elixirs - bc of hydroalcoholic character
spirits are a convenient means of obtaining a proper amount of…..
A FLAVORING OIL
ie - peppermint spirit USP
“clearm sweetened, hydroalcoholic liquids intended for oral use”
elixirs
**FDA limits on hydroalcoholic solutions for children
less than 6 yrs = less than 0.5%
6-12 yrs = less than 5%
children over 12 yrs = less than 10%
usually, less than ___% of preservatives are needed
less than 1%
how to differentiate between single and multi dose vials just from looking at the label
multi dose will have PRESERVATIVES
Explain what antioxidants are and why they may be added to solutions
substances that prevent or inhibit oxidation
added to protect the components that are subject to chemical degradation by oxidation
give some ex of antioxidants
vitamin c (ascorbic acid)
vitamin e (ascorbyl palmitate)
sodium bisulfate
sodium sulfite
BHA (butylated hydroxyanisole)
BHT (butylated hydroxytoluene)
tocopherol
monothioglycerol
LOOK FOR SULFATE.SULFITE, BUTYL, ETC
2 purposes of sweeteners/flavoring agents in solutions
-enhances viscosity
-gives pleasant taste and texture
_______ possess sweetening power that can be used for diabetic preparations
polyhydric alcohols (sorbitol, mannitol, glycerol)
**4 examples of common cosolvents
alcohol
glycerin
PEG400
propylene glycol
purpose of cosolvents in solution
to improve the solubility of poorly water soluble drugs
what do sufactants do?
reduce INTERFACIAL TENSION between particles and the liquid vehicle, thus promoting wetting and solubilization
CREATES A HOMOGENEOUS DISPERSION OF SOLID PARTICLES IN A LIQUID VEHICLE
Surfactants form ______ in solution when _____
micelles
at concentration over cmc (critical micelle concentration
when a surfactant is added to a water insoluble drug in water, where does the water insoluble drug go?
solubilized in the hydrophobic core of the micelle
4 examples of surfactants/solubilizers
tweens
spans
poloxamers
SLS
true or false
ascorbic acid is an antimicrobial preservative
FALSE - it’s antioxidant
is SLS a preservative
no - surfactant
true or false
solutions should be clear with NO PARTICLES VISIBLE
true
explain the general procedure for compounding solutions
- check solubility of all ingredients and make sure everything will dissolve in specified amount of solvent
- dissolve the solids in the solvent - AFTER TRITURATING THEM – BC SMOLER PARTICLES DISSOLVE FASTER!
- dissolve all powders at same time
- do the dissolution in a beaker with a stirring rod bc you can stir more effectively in a beaker than a grad cylinder
true or false
trituration is optional for solutions
true!
if you already know it will dissolve in the solvent, you dont NEED to triturate
where should you perform the dissolution when preparing solutions
IN A BEAKER - not grad cylinder
when dissolving solids to prepare solution, explain how much solvent you should use
for ex, if solubility of drug is 1g/5mL of water and the formulation calls for 20mL, use all of the 20mL to dissolve the drug
**when compounding solutions:
if the vehicle consists of more than 1 solvent (ie - alc and water) - which solvent should you dissolve the solid in??
the one in which the solid is MOST SOLUBLE
after the solid dissolves in this, add other solvents in order of decreasing solubility
ie - most soluble to least soluble
when the solid is completely dissolved in the solvents, the solution should be transferred to a ________ to be “qs’ed” with the vehicle
NEVER transfer to a ____
GRAD CYLINDER
NEVER TO A BOTTLE
in compounding solutions, we should never QS in a ___ or ____
beaker or bottle
***differentiate between how the strength of API is expressed for solutions depending on the ROUTE OF ADMINISTRATION
topical - %
oral - amt/vol of each dose
tocopherol is a preservative
(true or false)
FALSE - antioxidant. vitamin E
true or false
bentonite is NOT a preservative
TRUE - it’s a clay that can increase the thickness of topical ointments
true or false
cresol is not a preservative
FALSE - it is
true or false
Pharmaceutical solutions are chemically more stable than solid dosage forms
FALSE
true or false
alcohol is a vehicle used for topical solutions only
FALSE - as long as below certain % as mentioned, can be oral.
true or false
syrups are concentrated aqueous solutions of sucrose containing 60-85% sucrose
TRUE
true or false
spirits are clear, sweetened hydroalcoholic liquids intended for oral use and contain 5-40% alcohol
FALSE
this is elixir
