Biotechnology
Chemical Kinetics
3 M
Henderson
Hasselbalch
Hasselbalch
Ionization
and pH partition
and pH partition
Solubility
100
What is the pH at which a protein has a net charge of zero called?
Isoelectric point (pI)
100
What is stability
Ability of a medication to maintain the original chemical, physical, microbiological, therapeutic, and toxicological specifications
100
A solution of sodium chloride (MW 58.5 g/mol) is prepared by dissolving 35 gram in 200 mL of water. How many moles are in this solution?
35 g / 58.5 g/mol
0.60 moles
100
Why are most drugs in the salt form?
To improve the solubility
100
Provide 2 common cations
Aluminum, Calcium, Magnesium, Potassium, and Sodium
100
How many parts of solvent needed for slightly soluble
100-1000
200
What is the term for a protein adhering to a surface, such as the inside of a vial?
Adsorption
200
What is zero order reaction
The loss of the drug is independent of the drug concentration. First order is dependent of the drug concentration
200
A solution of magnesium sulfate (120.37 g/mol) is prepared by dissolving 44 grams in 500 mL of water. How many millimoles are in this solution?
44 g/ 120.37 g/mol = 0.366 moles x 1000 =
366 mmoles
200
Is sodium hydroxide acidic or basic?
Basic
200
How many ions does dextrose dissociate into?
One
200
Can unionized drugs cross biological membranes?
yes, because it is highly lipophilic
Ionized drugs are hydrophilic making them excretable
300
What process occurs when misfolded proteined accumulate and clump together
Aggregation
300
A drug suspension (250 mg/mL) decays by zero-order kinetics with a reaction rate constant of 0.6 mg/mL/hour. What is the concentration of intact drug remaining after 80 hours?
Use C = C0 - K0 x t
202 mg/mL at 80 hours
300
A solution of dextrose (MW 180 g/mol) is prepared by dissolving 23 grams in 250 mL of water. What is the molarity?
23 g/ 180 g/mol = 0.128 moles
0.128 moles / .250 L =
0.511 M
300
What is the purpose of a buffer?
To resist changes in pH
300
If the pKa of a weak base is 5, what is the % ionization of the drug if the pH of the medium is 4?
Unionized: 10
Ionized: 90
300
What is the difference between unsaturated and saturated solutions?
Unsaturated: the amount of dissolved solute is below saturated point so more can be dissolved
Saturated: the amount of dissolved solute is at saturated point so no more solute can be dissolved
400
What is purity
The freedom from extraneous matter in the finished product
400
A drug solution (20 mg/mL) exhibits a first-order degradation with a rate of 0.0005 -day. How much drug will remain after 90 days?
Use C = C0 x e^-kt
19.1 mg/mL
400
A nurse has 250 mL of IV solution containing 10% dextrose in water (MW 180 g/mol). What is the molarity?
10 g x 250 mL / 100 mL = 25 g
25 g/ 180 g/mol = 0.139 mole
0.139 moles / .250 L =
0.556 M
400
If the Kb of ammonia is 1.8 x 10^-5 at 25 degrees Celsius; Calculate the pKa
pKb = -log(Kb)
-log(1.8 x 10^-5) = 4.74
pKa = pKw - pKb
14-4.74 = 9.26
400
Describe fick's first law of diffusion
substances will diffuse from a region of high concentration to a low concentration
Net diffusion from higher to lower concentration
400
How does increase in temperature affect the rate of solubility?
Increases solubility
500
What chemical process involves the breakdown of bonds through a reaction with water
Hydrolysis
500
A drug solution (40 mg/mL) decays by first order kinetics with a reaction rate constant of 0.04 -day. What is the half life?
Use t(1/2) = ln(2)/k
17.3 days
500
A solution of ferrous sulfate (MW 151.9 g/mol) is prepared by dissolving 45 g in 500 g of water. What is the molality?
45 g/ 151.9 g/mol = 0.296 moles
0.296 moles / .5 kg =
0.592 mol/kg
500
What is the pH of a buffer solution prepared with 0.7 M disodium phosphate and 4 M sodium acid phosphate (pKa = 7.21)?
pH = pKa + log (Salt/Acid)
pH = 7.21 + log 0.7 M (salt)/ 4 M (acid)
pH = 6.45
500
In the GI tract (pH = 7), a drug with the pKa 5 was: 1% ionized and 99% unionized. Is this drug basic or acidic?
Basic
500
What happens to solubility when viscosity increases?
Solubility decreases
600
What is the key difference between a biosimilar and an interchangeable product
Interchangeable: meets additional standard of producing the same clinical result as reference product and may be substituted without prescriber intervention where permitted by state law
Biosimilar: highly similar to reference product with no clinically meaningful differences, cannot be substituted for the reference product
600
What type of reaction is this
First order reaction
600
How many grams of magnesium sulfate (MW 120.37 g/mol) are in 900 mL of a 250 mM solution?
250 mmoles/L x 0.900 L = 225 mmoles
225 mmoles = 0.225 moles
0.225 moles x 120.37 g/mol =
27.08 g
600
Calculate the pH of a solution made by mixing 35 mL of 0.6 M benzoic acid and 50 mL of 0.2 M sodium benzoate (pKa=4.22)?
pH = pKa + log (mL x salt/ mL x acid)
pH = 4.22 + log (50 mL x 0.2 M/ 35 mL x 0.6 M)
pH = 3.90
600
What is the ionization if the pKa of a weak base is 6 when the pH is 6.5?
Unionized: 75%
Ionized: 25%
600
What factors decreases solubility in water? Provide two examples
Increase in melting point, converting from anhydrous to trihydrate form, when the length of hydrocarbons increase, removing a hydroxyl group
700
What is the name of the FDA application to seek approval to market a biological product and what information must it contain (6)
Biological license application
- manufacturing, chemistry, pharmacology, purity, potency, and clinical-effect information
700
A newly reconstituted product is labeled to be stable for 24 h
at 5 degrees C. It’s stored at 4 degrees C for 6 hours. At the 6 h mark, a nurse
removes the product from the fridge and accidentally leaves
the drug product out on the counter for an additional 1.2 h,
what is the remaining life of the product? (assume a Q10 of 2).
1.2 = t90/2^(20/10)
1.2 = t90/4
t90 = 4.8
24-6-4.8 = 13.2
13.2 hours
700
What is the difference between molality and molarity?
Molality is the concentration of a solution expressed in moles per kilogram of solvent. Molarity is the concentration of a solution expressed in moles per liter
700
What is the pH of a buffer solution prepared with 15 mL of 0.05 M ammonia and 24 mL of 0.07 M ammonium chloride? The Kb value of ammonia is 1.80 x 10^-5
Calculate pKb first --> -log(1.8 x 10^-5) = 4.74
pH = (14-4.74) + log (15 mL x 0.05 M / 24 mL x 0.07 M)
pH = 8.91
700
If the pKa of a weak acid is 4, what is the ionization if the pH is 4?
Unionized: 50%
Ionized: 50%
700
What does the Noyes-Whitney equation help us understand?
the rate at which a drug dissolves in a solvent under static conditions