Solutions and solubility

Question 1

solution

Answer 1

a homogenous mixture of 2 or more substances

Question 2

solubility

Answer 2

the number of parts of solvent (by volume) that willdissolve one part of solute (by weight)

Question 3

unsaturated solution

Answer 3

more solutedissolves.
No solid remains inflask.

Question 4

saturated solution

Answer 4

no more solute dissolves. Undissolved solid remains in flask.

Question 5

supersaturated solution

Answer 5

more solute than is normally possible.
Becomes unstable,crystals form

Question 6

Aqueous solubility of a drug

Answer 6

the concentration at which the solution is said to besaturated. Any further addition of the drug will result in drug precipitation

Question 7

when the components of a solution are of the same phase, are we more likely to talk in terms of miscibility or solubility?

Answer 7

miscibility

Question 8

is dissolution the same as reaction
how would you tell a dissolution from a reaction

Answer 8

no
dissolution is a physical change, and can be reversed to the original state by evaporation
if this cannot be done then it is a reaction

Question 9

pros of pharmaceutical solutions

Answer 9

Liquids easier to swallow more acceptable by paediatric and geriatric pts

Faster therapeutic response

Uniform distribution of drug through out the preparation, c.f.suspensions andemulsions.

Reduced irritation to the gastric mucosa

Question 10

Classification of solutions based on solvent polarity

Answer 10

aqueous and non aqueous

Question 11

advantages of aqueous solutions

Answer 11

Lack of toxicity
Non-expensive
Physiological compatibility

Question 12

disadvantages of aqueous solutions

Answer 12

could cause hydrolysis of some drugs

Question 13

has to do with dissolution

why is the maximum level of solubility pharmaceutically important

Answer 13

because it dictates the rate of dissolution

Question 14

how soluble are the following salts of drugs in water? and how are their respective solubility determined?
atropine sulfate
codeine phosphate
codeine sulfate
morphine sulfate
phernobarbital sodium

Answer 14

very soluble
freely soluble
sparingly soluble
soluble
freely soluble

determined by measuring the weight of solvent required to dissovle 1 gram of the solute or the drug

Question 15

why are the salts of drugs typically more soluble than the free base or uncahrged form of the drug itself

Answer 15

due to differences in their chemical properties like different ionization states, different intermolecular forces btn structure and polarity…etc

Question 16

types of water

Answer 16

portable
purified
water used for injections

Question 17

portable water

Answer 17

Water freshly drawnfrom the public watersupply (main system)and suitable fordrinking.

Question 18

purified water

Answer 18

Freshly boiled andcooled immediately before use to destroymicroorganisms

Question 19

porperties of water used for injections

Answer 19

is sterile
CO2-free
low electrical conductivity
low endotoxins
high purity
absence of pyrogens…etc

Question 20

types of pharmaceutical solutions

Answer 20

Solid-in-liquid
Liquid-in-liquid
Solid-in-solid
Gas-in-gas
Gas-in-liquid

Question 21

liquid in liquid solution

Answer 21

A liquid-in-liquid solution is a one-phase molecular dispersion of twoliquids which are MISCIBLE with each other (e.g. ethanol and water).

Question 22

Solid-in-solid solutions

what do solid in solid solutions result to

Answer 22

A solid-in-solid solution is a molecular dispersion of a solid solute ina solid solvent.

the formation of a mixed crystal of both components

Question 23

importance of a solid-in-solid solution

Answer 23

can be used to enhance the dissolution of a poorly soluble drug.

Question 24

total moles of a solution formula

Answer 24

moles of solute + moles of solvent

Question 25

molarity (Formula)
molality (formula)

Answer 25

The number of moles of solute in ONE litre of solvent (moles of solute/ volume of solution)

The number of moles of solute in ONE kg of solvent (moles of solute/ mass of solvent)

Question 26

why is molality preferrable to molarity

Answer 26

It is independent of solution temperature (volume can change with temperature).It is unaffected by addition of another solute

Question 27

facotrs affecting solubility

Answer 27

particle size
pressure
temperature
polarity
polymorphs

Question 28

straight chain monohydric organic compounds like alcohols, with four or five carbon atoms cannot enter the hydrogen bonded structure of water, true or false

Answer 28

true, hence they are only slightly soluble

Question 29

ways to enhance solubility

Answer 29

co-solvency
pH adjustment
chemical modification
salt formation
adjusting temperature
particle size control

Question 31

How does temperature influence the solubility of gases in liquids?
reason for answer

Answer 31

Generally, the solubility of gases in liquids decreases with increasing temperature.

Increasing temperature imparts greater kinetic energy to gas molecules, weakening the intermolecular forces between gas and liquid. This reduces gas solubility in liquids, as higher energy levels hinder the formation of stable gas-liquid interactions.

Question 32

What is the purpose of using solubility charts or tables in pharmacy?

Answer 32

provide information on the maximum amount of solute that can dissolve in a given solvent under specific conditions.