SOLUBILITY Flashcards
concentration of a substance (solute) that dissolves in a given volume of solution (solvent) at a certain temperature to form a homogenous solution
SOLUBILITY
describes the solubility at a specific pH
buffer solubility
buffer solubility is also known as
apparent solubility
refers to the solubility of an ionizable compound in its neutral form
intrinsic solubility
the concentration of solute in a saturated solution at a certain temperature
QUANTITATIVE SOLUBILITY
the spontaneous interaction of two or more substances to form a homogenous molecular dispersion
QUALITATIVE SOLUBILITY
solute in solution is in equilibrium with the solid phase
SATURATED
- solute concentration < saturation point
- the dissolved solute in a concentration is below the necessary for complete saturation
UNSATURATED
- solute concentration > saturation point
- contains more of the dissolved solute than it would normally contain
- undissolved solute is present
SUPERSATURATED
the USP classified solubility into how many groups
7
Refer to standard reference works such as official compendia (e.g., USP, European pharmacopoeia) and the Merck Index for solubilities of specific substances.
United States Pharmacopeia (USP)
Solubility of drugs as parts of solvents required for one part of solute
United States Pharmacopeia (USP)
The greater the ____ between the solute and the solvent (similar physical-chemical properties), the greater the solubility
SIMILARITY
like dissolves like
Polar groups (-OH, -SH, -COOH) relationship w water solubility
increase
Non-polar groups (-CH3) relationship w water solubility
decrease
Ability to form H-bonds is
more significant
Polar solvent dissolve ____ or ____ solutes
ionic or polar
dissolves phenols, alcohols, aldehydes, ketones, and amines
water
Solubility of drug is due in large measure to ____
polarity of the solvent
solubility also depends on ____ features
structural
SOLUBILITY
longer chains
less soluble
SOLUBILITY
straight chain
slightly soluble
increases water solubility
branching
separation of the ends of a dipole and the magnitude of the charges
dipole moment
a quantity measuring the ability of a substance to store electrical energy in an electric field
dielectric constant
ability to store electrical charge
dielectric constant
decreasing polarity (less polar), decreasing water solubility (less water-soluble)
lower dielectric constant
solvents that are unable to reduce the attraction between ions of strong & weak electrolytes because of the solvents’ low dielectric constants
Nonpolar solvents
- can induce a certain polarity in nonpolar solvents
- e.g. ketones & alcohols
- can act as intermediate solvents
semipolar solvents
MISCIBILITY
benzene + alcohol
miscible
MISCIBILITY
polar + nonpolar liquids
miscible
MISCIBILITY
PEG + water + peppermint oil
miscible
REMEMBER
decreasing dielectric constant
decreasing polarity
decreasing solubility
TYSM