Pharmaceutics exam 2 study

The term “miscible” would apply to which state of matter? Solid | Liquid | Gas

Liquid

What is the term used for a liquid state of matter going to a gas?

Evaporation or vaporization

Which state of matter has the most ordered structure?

Solid

Most active pharmaceutical ingredients (APIs) are which state of matter? Solid | Liquid | Gas

Solid

For the states of matter listed below, rank them in the order of how ordered the molecules in that state of matter is (i.e. “1” would be the most ordered structure): Solid, Liquid, Gas

1 Solid; 2 Liquid; 3 Gas

Name two variables that will affect the phase in which a chemical exists.

Any two: temperature, pressure, concentration

Most solid drugs will have a phase diagram similar to the one shown here. True or False

False

What specific phase(s) is/are present in each of the following areas? Mark ALL that apply.

Read each region from the phase diagram: above both curves = liquid mixture; between a curve and eutectic line = one solid plus liquid mixture; below eutectic line = both solids.

How many degrees of freedom exist at a temperature of 40°C and a composition of 70% Drug Spring?

1 degree of freedom; F = C − P + 1 = 2 − 2 + 1 = 1

The eutectic point occurs at _____ °C and _____ % Drug Spring, and _____ degrees of freedom exist at this point.

12°C, 27% Drug Spring, and zero degrees of freedom

The point at approximately 46% Drug S and 50°C is known as the _____ point.

Eutectic point

What is the melting point of pure Drug Hallo?

Approximately 220°C

Two solids that form a eutectic mixture would be a disadvantage in which type of dosage form?

A dry, solid dosage form

A eutectic mixture would be a disadvantage in which type of dosage form? Why?

A dry, solid dosage form because the solids forming a liquid would cause the dosage form to become sticky and clumpy.

Two chemicals that form a eutectic mixture would be an advantage in a SOLID | LIQUID | GAS dosage form. Why?

Liquid; incorporating the drugs as a liquefied mixture can eliminate grittiness.

What is the general term used to describe reducing particle size of a solid to a finer state of subdivision?

Comminution

There are four main objectives of comminution (i.e. why would reducing particle size be important). Name two of them.

Any two: increase dissolution rate; aid the formulation process; enhance absorption; facilitate crude-drug extraction.

_____ is the manual comminution method of grinding a drug using a mortar and pestle to reduce its particle size.

Trituration

The use of a liquid in which the solid is soluble to aid in particle size reduction…

Pulverization by intervention

The process of grinding a small amount of powder using a pill tile and spatula…

Spatulation

Which manual technique can only be used for liquid and semisolid dosage forms?

Levigation

Which mechanical comminution technique cannot be used for drugs that are thermolabile?

Spray drying

In the mechanical comminution technique of lyophilization, temperature and pressure are INCREASED | DECREASED to bring the solvent to its BOILING | FREEZING | SUBLIMATION point.

Temperature and pressure are decreased to bring the solvent to its sublimation point.

Which mechanical technique utilizes sublimation of the solvent to reduce particle size by starting with the drug in solution then decreasing temperature and pressure?

Lyophilization

Name one mechanical comminution technique based on #7.

Lyophilization or spray drying

Comminution of a solid will increase its dissolution rate. Why?

Comminution decreases particle size, which increases the total surface area exposed to solvent and therefore increases dissolution rate.

You have a cubic drug particle of anacanapanasan that is 550 mcm on edge. How many smaller particles will be formed and what would be the new total surface area (in cm²) if this particle is broken down into cubic particles that are 25 mcm on edge?

10,648 particles and 0.399 cm²

All solutions are transparent. True or False

True

There are three main characteristics of solutions. One is that they form spontaneously, or without assistance. List one of the other two characteristics.

They are transparent, or their particles are in their smallest size.

In order for a solution to form, the solute’s intermolecular forces of attraction must be overcome by…

Attractive forces between solute and solvent molecules

A solvent with a low dielectric constant would be LESS | MORE polar than a solvent with a high dielectric constant.

Less polar

Alcohols have a dielectric constant (ε) of 30 and glycols have a dielectric constant of 50. Which of these substances would be the most polar?

Glycols

Polar solvents have High | Low dielectric constants and solubilize compounds by… (Mark all that apply): Van der Waals forces | Hydrogen bonding | Magic

High dielectric constants; hydrogen bonding

Which type of solvent dissolves a solute through dipole interactions (a.k.a. van der Waal’s forces)? Polar | Nonpolar

Nonpolar

A drug has a diffusion coefficient of 0.29 cm²/hr when prepared in an aqueous solution, a stagnant layer length of 2.08 cm with no agitation, and a surface area of 7.67 cm². The solubility of this drug is 11.23 mg/mL at 25°C. How long will it take for 25 mg of this drug to dissolve?

2.08 hours, or approximately 2 hours 5 minutes. First calculate rate = DAS/ℓ = 12.01 mg/hr, then 25 mg ÷ 12.01 mg/hr.

How can the length of the stagnant layer be reduced in #12 to increase the dissolution rate?

Stir or agitate the mixture

A high-viscosity solvent would have a higher | lower | same dissolution rate for a drug than a lower-viscosity solvent because…

Lower; a high-viscosity solvent creates a longer stagnant layer, causing a slower dissolution rate.

Heating a mixture will usually increase the dissolution rate of the solute, because heat will most likely affect which variable related to dissolution rate? Surface area of the solute | Length of the stagnant layer | Solubility of the solute | None of these

Solubility of the solute

Name one situation where the statement in #24, heating a mixture will usually increase the dissolution rate of the solute, would not be true.

When the drug has a negative heat of solution

According to the relative terms of solubility, anacanapanasan is “soluble” in water as shown by the solubility given in #14. It is also “sparingly soluble” in ethyl alcohol and “freely soluble” in glycerin. Therefore, anacanapanasan has the highest solubility in… Water | Ethyl alcohol | Glycerin

Glycerin

Which of the following will affect the solubility of a drug? Mark ALL that apply. Particle size | Agitation of the mixture | Temperature | pH

Temperature and pH

Decreasing the particle size of a solute will increase its solubility. True or False

False; it increases dissolution rate, not equilibrium solubility.

You need to increase the solubility of an acidic drug with a positive heat of solution. Which of the following will help you increase the solubility of this drug? (Mark ALL that apply): Increase the pH | Decrease the pH | Reduce the particle size of the drug | Increase the temperature | Decrease the temperature | Stir the solution vigorously and continuously

Increase the pH and increase the temperature

Sodium bicarbonate has a solubility of approximately 100 mg/mL in water at 25°C, and the heat of solution for sodium bicarbonate is 2.81 kcal/mol. What is the solubility of sodium bicarbonate at 60°C?

164.69 mg/mL

What would be one problem with heating the solution as described in #18 to increase the solubility of sodium bicarbonate?

Any one: drug instability, solvent evaporation, or the solution must remain at the higher temperature to maintain solubility.

In general, if the pH of a solution decreases, the aqueous solubility of a basic drug will Increase | Decrease | Cannot be determined from the information given

Increase

In general, a/an increase | decrease in pH will increase the aqueous solubility of an acidic drug & decrease the aqueous solubility of a basic drug.

Increase

When calculating the effect of pH change on solubility, the solubility must be expressed in what units? Why?

Molarity, to account for the chemical change that occurs and affects molecular weight.

In general, the presence of other compounds in a solution will decrease the solubility of the drug because of competition for solvent binding. However, a compound might be added for solubilization or complexation of the drug. Which of these two would be the most likely to cause chemical degradation of the drug? Solubilization | Complexation

Complexation

Solubilization is a Chemical | Physical phenomenon and complexation is a Chemical | Physical phenomenon used to increase the solubility of a drug.

Solubilization is physical; complexation is chemical.

Besides the techniques described in #16, #18, and #19, what is one other factor that will affect solubility or a technique that can be done to increase solubility?

Add a cosolvent or change the drug to its salt form.

When an additional solvent is added to the primary solvent to increase solubility, the additional solvent is known as a/an _____.

Cosolvent or adjunct solvent

Sodium bicarbonate is available as an 8.4% w/v aqueous solution with a specific gravity of 1.04. What would be the strength of this solution expressed as % w/w and molarity? (m.w. NaHCO₃ = 84)

8.08% w/w and 1 M

A saturated solution of potassium permanganate at 25°C has a concentration of 76 mg/mL. Express the concentration as % w/v and molarity. (m.w. KMnO₄ = 158.03)

7.6% w/v and 0.481 M

Fentanyl citrate injectable solution is available in a prefilled syringe with a concentration of 25 mcg/0.5 mL. Express this concentration as a ratio strength and molarity. (m.w. fentanyl citrate = 528.6)

1:20,000 w/v and 0.000095 M, or 9.46 × 10⁻⁵ M

Syrup NF is an aqueous solution containing 85% w/v sucrose and has a specific gravity of 1.313. Express this concentration in mg/mL and molarity. (m.w. sucrose = 342.3)

850 mg/mL and 2.48 M

Colligative properties depend on the number of particles (or ions, or molecules) in solution. True or False

True

Which colligative property is the most important physiologically?

Osmotic pressure

Osmotic pressure is the pressure needed to stop the passage of _____ through a semipermeable _____.

Solvent; membrane

Citra pH® is an antacid solution containing 2.7 g of sodium citrate dihydrate in 30 mL aqueous solution. A. The boiling point of this solution would be higher than | lower than | exactly 100°C. B. The freezing point of this solution would be higher than | lower than | exactly 0°C.

A. Higher than 100°C. B. Lower than 0°C.

Why should the concentration of solution be multiplied by the dissociation factor (i) when calculating a colligative property of a solution such as vapor pressure lowering?

Colligative properties depend on the number of particles in solution, so i accounts for the particles produced by dissociation.

A change in one colligative property can be used to predict a change in the other colligative properties. Why is this statement important?

Osmotic pressure is physiologically important but difficult to measure; freezing- or boiling-point changes are easier to measure and can predict osmotic pressure.

A change in one colligative property can be used to predict a change in the other. True or False

True

Sodium bicarbonate (NaHCO₃) is a 2-ion electrolyte, whereas sodium carbonate (Na₂CO₃) is a 3-ion electrolyte. If a solution of sodium carbonate is prepared at the same molar concentration as the solution in #20, the freezing point of this solution would be ____ the freezing point of the sodium bicarbonate solution in #20. Higher than | Lower than | Exactly | Not enough information to determine

Lower than

Name one of the USP methods for preparing purified water.

Distillation, ion exchange, or reverse osmosis

The most common solvent used in pharmaceutical preparations is…

Water

Alcohol USP contains _____% v/v ethyl alcohol.

95% v/v

What is the key ingredient in a syrup? (what ingredient added to an aqueous solution makes it a syrup?)

Sucrose or another sweetener

Which type of oral solution would be better at taste masking in general? Syrup | Elixir

Syrup

A/an Syrup | Elixir would be easier to prepare.

Elixir

Why should elixirs not be prepared using the technique in #24?

They contain alcohol, which will evaporate if heated.

Name two advantages of an elixir as a dosage form in comparison to other solution dosage forms.

Any two: easy to prepare; microbiologically stable; physically stable; lower chance of solubility problems.

FDA recommends an alcohol content limit of _____ in nonprescription products for children 6–12 years old. 0.5% | 2% | 5% | 10% | 20%

5%

A/an _____ is a clear, sweetened, hydroalcoholic solution intended for oral use, and is usually flavored to enhance its palatability.

Elixir

A collodion is a liquid preparation composed of _____ dissolved in a 3:1 mixture of _____:_____.

Pyroxylin; ether; ethyl alcohol

Which ingredient in #28 causes it to be highly flammable?

Ether

A/an _____ is an alcoholic or hydroalcoholic solution prepared from vegetable materials or from chemical substances. Elixir | Tincture | Spirit | Aromatic water | Liniment

Tincture

In an extraction process the solvent used to extract the active ingredient(s) is the… Marc | Extractive | Menstruum | Percolator | Crude drug

Menstruum

The “leftovers” in an extraction process after all the desired constituents have been removed is known as the… Extractive | Menstruum | Marc | Percolate

Marc

A/an _____ is a proton donor and a/an _____ is a proton acceptor.

Acid; base

An acid with a low Ka would be Weaker | Stronger than an acid with a high Ka.

Weaker

A weak acid completely dissociates in water. True or False

False

Calcium hydroxide is a weak base, which means that it completely ionizes in water. True or False

False

Calculate the pH of 0.075 M sodium hydroxide.

12.88

What is the pH of a calcium hydroxide solution with a concentration of 1.4 mg/mL? (m.w. Ca(OH)₂ = 74, pKb = 2.37)

11.95

Atropine is a weak base with a Kb of 4.5 × 10⁻⁵ and a molecular weight of 289.4. What would be the pH of an injectable solution containing 2 mg of atropine in 0.7 mL of solution?

10.82

Fentanyl citrate is a weak acid with a Ka of 2.02 × 10⁻⁹. What would be the pH of the solution in #19?

6.36

A buffer is usually a/an _____ solution that resists changes in _____.

Aqueous; pH

The primary function of a buffer is to resist changes in _____.

pH

The definition of buffer capacity is the ability of a buffer solution to resist _____ upon addition of _____.

pH changes; acid or base

A pharmaceutical formulation contains a buffer for enhancing/maintaining the _____ of the drug in most cases. Solubility | Stability | Activity | Absorption | Patient comfort

Stability

Name two reasons why controlling the pH of a formulation might be important.

Any two: drug stability, drug solubility, drug activity, drug absorption, patient comfort.

When buffering a formulation for stability purposes, the pH should be maintained where the rate constant (k) is the… Lowest | Highest | Not enough information to determine

Lowest

A buffer is prepared by mixing 150 mL of 0.1 M phosphoric acid with 200 mL of 0.05 M sodium phosphate monobasic. What is the pH of this buffer? (Ka of phosphoric acid = 7.5 × 10⁻³, both solutions are aqueous so assume volumes are additive)

1.95

A borate buffer has a buffer capacity of 0.075 M and a pH of 6.7. How much sodium hydroxide (in milligrams) should be added to 250 mL of this buffer to raise the pH to 7.4? (assume negligible volume displacement by the sodium hydroxide, m.w. NaOH = 40)

525 mg

An acetate buffer has a buffer capacity of 0.04 M and a pH of 7.5. If 20 mL of 0.5 M HCl is added to 100 mL of this buffer, what would be the predicted pH? (m.w. HCl = 36.5, assume volumes are additive)

5.42

Calculate the pH of the following buffer: Sodium phosphate, monobasic 0.2 M—120 mL; Sodium hydroxide 0.1 M—80 mL; Water q.s.—250 mL. pKa NaH₂PO₄ = 7.21, m.w. NaH₂PO₄ = 120, m.w. Na₂HPO₄ = 142, m.w. NaOH = 40

6.91

What would be the buffer capacity of the buffer in #34? (Hint: you can calculate the buffer capacity by first calculating the pH change after adding a certain amount, i.e. 0.003 mole, of HCl or NaOH, and assume negligible volume displacement, or you can use Van Slyke’s equation)

Approximately 0.05 M by Van Slyke’s equation; the worked acid/base methods give approximately 0.043–0.053 M.