Lab 3 Flashcards
Name 2 uses for the Henderson-Hasselbach Equation
1.Calculating ratio of ionized to unionized species of a molecule when preparing buffer solutions
- To predict absorption, distribution, and excretion properties of a drug
What does pKa determine?
Gives the relative acid strength of a molecule
As pKa decreases, acidity _____
increases
As Ka increases, acidity______
increases
Are drugs in their ionized or nonionized form? Why?
Non ionized because they are lipophilic and will cross the cell membrane
The distribution of a drug can be manipulated by____
changing the pH
If you want a basic drug to be excreted from the body you should ____ the pH of the urine
decrease
What 2 things does solubility depend on?
- Molecular properties of the solute and solvent
- Temperature
What is intrinsic solubility?
Maximum amount of solute that can dissolve in a specified volume of solvent
Water-soluble compounds dissolve in water primarily via which two bonds?
Hydrogen and ionic
For weak acids, ionization _____ with increasing pH
increases
For weak bases, ionization ____ with decreasing pH
increases
Degree of ionization can be calculated using ______
Hendersen-Hasselbach equation
How to find [HA] if using a base??
plug in absorbance value for buffer into the standard curve equation as “y.” solving for x will give [A-]. To find [HA] subtract [A-] from C2
What is the formula for calculating molar extinction coefficient if using an acid?
E = absorbance/ 1cm * [HA]M
How to calculate intrinsic aqueous solubility?
Given intrinsic solubility (mg/mL) * final volume in mL
concentration could be measured in _____ or _____
g/L or mg/mL
How to calculate non intrinsic solubility??
mg solute - mg intrinsic aqueous solubility
How to calculate critical solubilizing pH??
pka + log [insoluble]/[intrinsically soluble]
The formation of a solution in a solute and solvent system is a _____ process
physical
When is a solution considered saturated?
Once the compound reaches maximum solubility
The interactions that determine the solubility of a substance in a liquid depends largely on ______
The ability of the solute to interact and form bonds with the solvent
Name 3 ways supersaturated aqueous solutions can be prepared
Manipulating pH, temperature, and mixing solvents
What 2 terms describe the phenomenon by which excess solute falls out of solution
crystallization and precipitation