Exam 2- Lecture 7 (Part II of Dosage Form Design: Biopharmaceutical Considerations)

Question 1

What is the rate limiting step for absorption?

Answer 1

Dissolution

Question 2

What is dissolution?

Answer 2

Amount of substance that goes into solution per unit time under standard conditions of liquid solid interface: temperature and solvent

Question 3

The solvent of oral formulations?

Answer 3

Gastric fluid

Question 4

How does temperature affect dissolution?

Answer 4

As temperature increases the rate of dissolution increases because high temps break bonds and the drug is available at a faster rate.

Question 5

Noyes Whitney equation is used to determine what?

Answer 5

Drug concentration with respect to time

Question 6

What physiological factors affect dissolution?

Answer 6

Solubility

pKa

Size

Excipients

Viscosity of medium

Temperature

pH of medium

Question 7

What are the formulation factors that affect dissolution?

Answer 7

Diluent: what the solute is being dissolved in

Disintegrating agents: high concentration of these agents will break down the drug before you want it to

Lubricants: hydrophobic, too much lubricant can prevent breaking of tablet. Has low water solubility

Question 8

What are the processing factors that affect dissolution?

Answer 8

• Method of granulation: wet vs. dry. Wet is preferred
• Compression force: too much force can cause the tablet to be too hard. Result in dense cake

Question 9

How do particle size, surface area, and rate of disassociation relate to one another?

Answer 9

Decrease particle size:

increase surface area

increase the rate of dissolution.

Question 10

Which is more soluble the amorphous form or crystallation form?

Answer 10

Amorphous form

Question 11

With time the rate of dissolution increases or decreases?

Answer 11

Decreases, once you reach peak, rate decreases because there is more drug in the bulk layer than the stagnant layer.

Question 12

How does hydration, food, pH of GI tract, absorption, drug interactions and aging affect dissolution?

Answer 12

Hydration:

• anhydrous forms have higher solubility than hydrate form

Food:

• affects how quickly the drug can pass through stomach, food can decrease the rate of dissolution

pH:

• increase or decrease

Absorption:

• reduces absorption because molecules can absorb to insoluble materials

Drug interactions:

• some molecules reduce absorption when bound to certain drugs

Aging:

• physiological changes as you age
• pH, SA of endostein, and body response to a drug changes

Question 13

What is bioavailability?

Answer 13

• Rate and extent of active drug that is absorbed from drug product and becomes available at site of action
• How fast and how much of the drug is going into the systemic circulation

Question 14

What is bioequivalence?

Answer 14

Comparing bioavailability of different formulations, drug products, or different batches of the same drug product

• A generic drug and brand drug are bioequivalent when there is no statistically significant difference between rate and extent of absorption

Question 15

What is bioavilabiity used to determine?

Answer 15

• Amount drug absorbed from dosage form
• Rate drug is absorbed
• Duration of drug’s presence in body
• Relationship between blood levels and efficacy of drug

Question 16

What is MEC?

Answer 16

Minimum effective concentration:

• minimum amount of drug concentration to be considered effective. (below won’t be effective)

Question 17

What is MTC?

Answer 17

Minimum toxic concentration:

• minimum amount of drug concentration that can be considered toxic (side effects can happen)

Question 18

Brands are cheaper than generics?

Answer 18

False, generics don’t have to go through the same pre-clinical and clinical stages that brand products have to go through

Question 19

Similarity in Generic and Brand Drugs

Answer 19

• mechanism of action
• active ingredients
• efficacy
• Formulation (recipe- exact quantities)
• route of administration
• dosage form
• strength
• conditions of use

Question 20

The only difference between brand and generic is the in-active ingredients? (excipients)

Answer 20

True

• Differences in inactive ingredietns results in some side effects to patients if they are susceptible to certain inactive ingredients

Question 21

Generic drugs are only required to do bioequivalence and bioavailability testing.

Answer 21

True

Question 22

FDA can give drug exclusivity for 6 months to 7 years

Answer 22

True

Question 23

US trade mark and US patent gives patent protection for 20 years.

Answer 23

True

Question 24

What if a new indication arises for the drug?

Answer 24

Will have to do some small trials to verify. Doesn’t have to go through whole process again. After that, the new indication will be able to be added to the label