session 7 practice problems

a liquid preparation of one or more chemical compounds in a suitable solvent or mixture of miscible solvents

solution

these dissociate into solvated ions in solution

electrolytes

this includes both the active pharmaceutical ingredient (API) and usually other excipients

dosage form

the chemical compound dissolved in a solvent or mixture of miscible solvents

solute

a heterogeneous mixture of finely divided solid particles in a liquid; particles can settle over time and may be removed by filtration

suspension

a feature of solutions that refers to them having uniform appearance and composition throughout

homogenous

at a constant temperature, the solubility of a gas (Cg) in a particular solvent increases as the partial pressure (Pg) of the gas above the solution increases

Henry’s law

molar volume, aqueous solubility, lipophilicity, physical form, and pKa are all examples of these

physiochemical properties

a combination of two immiscible liquids in which one is finely and uniformly subdivided throughout the second; usually translucent or opaque and cannot be separated by filtration

emulsion

these contain less than the maximum amount of dissolved solute at a given temperature

unsaturated solutions

the density of a substance relative to the density of water

specific gravity

the most common mechanism of membrane permeation for small molecule drugs

passive diffusion

BIOAVAILABILITY (F) is the fraction of administered drug that reaches circulation. Bioavailability varies across different dosage forms, routes, and formulations. Results from an IV dose are typically set as F = 100%. Which of the following likely impacts the oral bioavailability of a drug?

 

the drug’s solubility in intestinal fluid

 

both the drug’s solubility in intestinal fluid and its ability to permeate GI epithelial cells

 

the drug’s ability to permeate GI epithelial cells

 

neither the drug’s solubility in intestinal fluid nor its ability to permeate GI epithelial cells

both the drug’s solubility in intestinal fluid and its ability to permeate GI epithelial cells

Both drug A and drug B are liquid medications. Drug A is dosed orally (PO) while drug B is dosed intravenously (IV) or intramuscularly (IM). The instructions for dosing drug A say to shake well before using. Which statement is most likely to be TRUE?

 

Neither medication is a solution

 

Both medications are solutions

 

Only medication B is a solution

 

Only medication A is a solution

Only medication B is a solution

Some cancer cells overexpress the efflux transporter known as P-glycoprotein (P-gp). Some chemotherapy drugs like paclitaxel are P-gp substrates, meaning that the transporter can move the drug across cell membranes. What can you conclude about the utility of drugs like paclitaxel to treat such cells?

 

Drugs like paclitaxel will be less effective treatments against cancer cells that overexpress P-gp.

 

Drugs like paclitaxel will be more effective treatments against cancer cells that overexpress P-gp.

 

P-gp expression will have no effect on the effectiveness of drugs like paclitaxel.

Drugs like paclitaxel will be less effective treatments against cancer cells that overexpress P-gp.

The solubility of solids in liquids generally increases with increasing temperature.

 

True

 

False

True

Particle size reduction can enhance the absolute solubility of a pure chemical substance held at a constant temperature and pressure.

 

True

 

False

False

Unsaturated solutions contain the maximum amount of dissolved solute at a given temperature.

 

True

 

False

False

The solubility of gases in liquids decreases with increasing temperature.

 

True

 

False

True

Melting point is an example of an ____ physical property.

intensive

Density is an example of an _____ physical property.

intensive

Regardless of dosage form or route of administration, a drug must be in ________________ to be absorbed.

solution

The rate at which a solute goes into solution can vary depending on factors such as degree of agitation.

 

True

 

False

true

_______________ electrolytes dissociate partially into ions in solution.

weak

The efflux transporter known as P-glycoprotein (P-gp) is highly expressed at the blood-brain barrier. The compounds carebastine and chlorpheniramine both antagonize histamine H₁ receptors. Antagonism of histamine H₁ receptors in the brain is associated with drowsiness. Carebastine is a substrate of P-gp; however, chlorpheniramine is not. Given this information, and assuming doses of each compound that lead to identical concentrations in the blood, which compound will be least likely to cause drowsiness?

 

chlorpheniramine

 

carebastine

 

both drugs will cause drowsiness

carebastine

Categorize the following four physical properties as intensive or extensive.

• Boling point =

• Mass =

• Specific gravity =

• Volume =

• intensive

• extensive

• intensive

• extensive

What is the term for a heterogeneous mixture of finely divided solid particles dispersed in a liquid?

 

suspension

 

solution

 

emulsion

suspension

The absolute solubility of a pure chemical substance at a given temperature and pressure is constant, but the rate of solution varies and depends on other factors such as particle size and degree of agitation.

 

True

 

False

True

Some cancer cells overexpress the efflux transporter known as BCRP. The chemotherapy drug mitoxantrone is a substrate of BCRP, meaning that the transporter can move the drug across cell membranes. Biopsies from two cancer patients, BB and PL, determine that BB's cancer overexpresses BCRP but PL's cancer does not. Given this information, and assuming all other things are equal, which patient is more likely to respond to mitoxantrone therapy? 

 

PL

 

BB

 

PL and BB are equally likely to respond

PL

The density of a substance relative to the density of water is known as that substance's:

specific gravity

At a constant temperature, the solubility of a gas in a particular solvent ______ as the partial pressure of the gas above the solution increases

increases