Acid-Base Solutions

The smaller the pKa...

the more acidic the compound

What is the implication of the double arrows in an esterification reaction ?

The reaction is reversible

What is the main acidic functional group for drug structures?

-COOH Carboxylic Acids

What are the other 4 acidic functional groups common in drug structures?

Sulfonic Acid
Phosphoric Acid
Sulfonamide
Active Hydrogen

sulfonic acid

Phosphoric Acid

Sulfonamide

What are the 4 properties that make up a drug?

1. State of Matter
2. Molecule Size
3. Acid-Base Properties
4. Net Charge/Charge of the drug

What is the meaning of amphoteric?

a compound that has both acid and base groups

Are Amino Acids amphoteric?

Yes

What makes a group/compound neutral?

having no ionizable groups

What is a Bronsted Acid?

Proton Donor

What is a Lewis Acid?

Electron Pair Acceptor

What is a Bronsted Base?

Proton Acceptor

What is a Lewis Base?

Electron Pair Donator

What are the 4 structures of proteins?

primary, secondary, tertiary, quaternary

What is acid strength determined by?

pKa

pKa \=

-logKa

What does pKa measure?

disassociation ionization

What is correlation between disassociation of ionization and Strong acids?

If most of it disassociates that means it is a strong acid

What is correlation between disassociation of ionization and Weak acids?

if NOT a lot of it disassociates, then it is a weak acid

Ka \=

\[H3O+][A-]/[HA]

Henderson-Hasselbalch equation

pH \= pKa + log [base]/[acid]

Le Chatelier's Principle

when stress is applied to a system at equilibrium, the system changes to relieve the stress

STRONG ACID pKa value

x<2

Weak acid pKa value

4-6

Very weak acid pKa value

8-10

Not acidic in H2O pKa value

x\>12

STRONG BASE pKa Value

x\>12

Weak Base pKa Value

8-10

Very weak base pKa value

4-6

no basic properties

x<2

A Strong Acid has a...

weak Conj. Base

A weak acid has a...

STRONG Conj. Base

A Strong Base has a...

weak Conj. Acid

A Weak Base Has a...

Strong Conj. Acid

percent ionization for HA acids

100/1+10(pKa-pH)

percent ionization for BH+ acids

100/1+10(pH-pKa)

Find the LogP
Partition Coefficient: 1000

3

Find the Partition Coefficient
LogP: 2

100

Find the Partition Coefficient
LogP: 1

10

Find the Partition Coefficient
LogP: -5

0.00001

Find the LogP
Partition Coefficient: 0.001

-3

Find the LogP
Partition Coefficient: 1

0

Find the LogP
Partition Coefficient: 100,000

5

What does pKa stand for?

It is the pH at which a substance is half dissociated in a substance.

Cation exchangers are __________ charged.

negatively

Anion exchangers are __________ charged.

positively

The pI of a protein is 3.7. At physiological pH, it will bind to what type of ion-exchanger; positive or negative?

neither

The pI of a protein is 11.1. What type of IEC resin will it bind to at pH 7.4?

If the pI is greater than the pH, the molecule will have a positive charge meaning it will bind to a Negatively charged resin.

What is the meaning of pI?

the pH at which the net charge of a protein molecule is zero.

How would a protein in a buffer whose pH is equal to the pI behave in an electric field?

It will not move

How would you classify ion-exchange resins?

They can be described as cationic and anionic, then further subcategories include weak and strong.

Weak cationic exchangers have what type of groups?

COO-, Strong acid groups

Strong cationic exchangers have what type of groups?

SO3-, weak acidic groups

Weak anionic exchangers have what type of groups?

DEAE groups

Strong anionic exchangers have what type of groups?

Quaternary amino groups

What is the main characteristic of ion-exchange resins that make them different from other chromatographic resins?

their ability to bind and exchange ions based on their electrostatic interactions.

A researcher reacted an antibody with a red fluorescent molecule to help reveal the cellular location of an antigen in the cell. The process of reacting the antibody with the fluorescent molecule is known as:

Derivitization

When given an organic drug molecule, how would you determine whether it is an acid?

Look for the 6 acidic functional groups

What is an example of derivatization?

converting a drug into a prodrug

What do you understand by resolution in Chromatography?

Measure of the efficiency of a chromatographic separation

What is the resolution formula?

R2-R1/W1+W2(0.5)

Adsorption definition

Molecules stick to the surfaces of particles

Absorption definition

molecules soak into the particles

Elution defintion

\n The process of separation and removal of compounds in a \n sample from a chromatographic column using a gas or liquid.

Retention volume definition

volume of the liquid used to elute any molecule.

Elution time definition

Time from start of the run to the apex \n of the peak on a chromatogram.

Injection definition

applying a sample for separation into a \n chromatographic column

peak definition

on a chromatogram represents at least one molecule, the size of the peak indicating the quantity of the molecule giving rise to that peak

Chromatogram definition

display of the results of a chromatographic run. It is a chart with peaks that represent various molecules that constituted the separated sample.

Chromatograph definition

instrument used to effect chromatographic separations.

Chromatography definition

science of molecular separation to purify, analyze or quantify substances

Matrix, Gel, Solid Support, Resin, \n Stationary phase

stable materials that are packed into columns or placed in other types of research containers as test tubes for molecules to bind to, washed and desorbed.

What are 2 versions of a buffer

weak acid w conjugate base OR weake base with conjugate acid

What is buffer capacity measured by?

concentration of buffer substance in solution , pka of buffer substance, and pH at which it is being used.

What is buffer capacity?

***quantifies the ability of a solution to resist changes in pH by either absorbing or desorbing H+ and OH- ions***.

Rule of thumb #1, Why does pKa need to be close to pH?

This is because there is an equal chance of resistance on each end.

Rule of thumb #2 pH range.

in between -1, and +1

Molarity definition

Moles of solute per liter of solution

Molality definition

Moles of solute per kilogram of solvent

What are some steps that are taken to maximize sample recovery?

\-Manipulating the pH

\-Salting out

\-Ion-pairing

\-Repeated extractions

 **natural proteins/amino acids**

__L configuration__

 **artificial proteins**

__D-Amino acids__

Something you should know about the solubility of polar and non-polar solvents

Like dissolves like

Percent ionization “HA” acid, pH is +1

90%

Percent ionization “HA” acid, pH is -1

10%

Percent ionization “HA” acid, pH is the same as pKa

50%

Percent ionization “HA” acid, pH is +2

99%

Percent ionization “HA” acid, pH is +3

99\.9%

Percent ionization “HA” acid, pH is -2

1%

Percent ionization “HA” acid, pH is -3

0\.1%

Percent ionization “BH” acid, pH is -6

99\.9999%

Percent ionization “BH” acid, pH is -4

99\.99%

Percent ionization “BH” acid, pH is -3

99\.9%

Percent ionization “BH” acid, pH is -2

99%