Study Set Content:
If it is not converted to its (blank) (polar or water soluble) form the drug will stay longer in the body as a result it will have an intensified pharmacological activity.
ionized
The un-ionized form is responsible for the
activity
while the ionized form enhances water solubility leading to
excretion of the drug
To be able to quantitatively predict the degree of ionization of a molecule, 1. the pKa values of each of the (blank) functional groups present
acidic and basic
the(blank) of the environment in which the molecule will be located must be known
pH
pKa is constant for any given functional group, the ratio of acid to conjugate base (or conjugate acid to base) will determine the pH of the solution.
Henderson Hasselbach
Henderson Hasselbach equation
The solubility of a drug molecule in water greatly affects the routes of administration that are available as well as its
absorption, and elimination
Two key concepts when considering the water (or fat) solubility of a molecule
a. Potential for hydrogen bond formulation
b. Ionization of one or more functional groups within the molecule
Each functional group capable of donating or accepting a hydrogen bond contribute to the overall
water solubility of the compound
Each functional group capable of donating or accepting a hydrogen bond contribute to the overall water solubility of the compound and increases the
hydrophilic (water-loving) nature of the molecule
Conversely, functional groups that cannot form hydrogen bonds do not enhance
hydrophilicity
Conversely, functional groups that cannot form hydrogen bonds do not enhance hydrophilicity and will contribute to the
hydrophobic (waterfearing) nature of the molecule.
A special case of what are usually referred to as dipole-dipole interactions
Hydrogen bonds
A permanent dipole occurs as a result of an (blank) sharing of electrons between the two atoms within a covalent bond
unequal
When the positive end of the dipole is a hydrogen atom, this interactions is referred to as a
“hydrogen” or h-bond
Thus, for a hydrogen bonding interaction to occur, at least one functional group must contain a dipole with an
electropositive hydrogen
The hydrogen atom must be covalently could bond to electronegative atom, such as
oxygen (O), nitrogen (N), sulfur (S), selenium (Se)
Of these four elements, only (blank) atoms contribute significantly to the dipole, hydrogen-bonding capability
oxygen and nitrogen
Of these four elements, only oxygen and nitrogen atoms contribute significantly to the dipole, hydrogen-bonding capability (specifically as hydrogen bond donors) of; a. Functional groups that contain a bond between
oxygen and hydrogen atoms e.g. alcohols
