MODIFIED RELEASE DRUGS

Question 1

Advantages of Modified-Release Dosage Forms

Answer 1

1) Less fluctuation in blood levels
2) Reduced dosing frequency
3) Enhanced convenience and compliance
4) Reduced adverse side effects
5) Overall reduction in health care cost

Question 2

Disadvantages of Modified-Release Dosage Forms

Answer 2

1) Loss of flexibility in adjusting the drug dose and/or dosage regimen
2) Risk of dose dumping

Question 3

Modified-Release

Answer 3

Release features are based on time, course, and/or location that are designed to accomplish therapeutic or convenience objectives not offered by conventional or immediate-release forms

Question 4

Extended-Release

Answer 4

Allows a reduction in dosing frequency compared to that of a conventional dosage form

Question 5

Delayed-Release

Answer 5

Releases the drug from the dosage form at a time other than promptly after administration

Question 6

Repeat Action

Answer 6

Usually contain two single doses of medication, one for immediate release and the second for delayed release

Question 7

Targeted-Release

Answer 7

Directed toward isolating or concentrating a drug in a body region, tissue, or site for absorption or for drug action

Question 8

Drug Candidates for Extended-Release Products

Answer 8

1) They exhibit neither very slow nor very fast rates of absorption and excretion
2) They are uniformly absorbed from the GI tract
3) They are administered in relatively small doses
4) They possess a good margin of safety
5) They are used in the treatment of chronic rather than acute diseases

Question 9

Modification of Rate of Drug Release

Answer 9

1) Modify drug dissolution by controlling access of biologic fluids to the drug through the use of barrier coatings
2) Controlling drug diffusion rates through dosage forms
3) Chemical reaction or interaction between the drug substance or its pharmaceutical barrier and site-specific biologic fluids

Question 10

Coated Beads, Granules and Microspheres

Answer 10

1) Drug is distributed onto beads, pellets, granules or other particulate systems
2) Variation in coat thickness affect rate at which fluids can penetrate the coating to dissolve the drug

Question 11

Multitablet Systems

Answer 11

Small spherical compressed tablets with varying drug release characteristics can be placed within gelatin capsule shells

Question 12

Microencapsulation

Answer 12

Process of enclosing solids, liquids or gases within microscopic particles by forming thin coatings of wall material around the substance

Question 13

Embedding Drug in Slowly Eroding or Hydrophilic Matrix Systems

Answer 13

Drug substance is combined and made into granules with an excipient material that slowly erodes in body fluids, progressively releasing the drug for absorption

Question 14

Embedding Drug in Inert Plastic Matrix

Answer 14

Drug is granulated with an inert plastic material and the granulation is compressed into tablets; drug is slowly released from the matrix by diffusion

Question 15

Complex Formation

Answer 15

Chemical combination of drug substance with other agents to form complexes that may be only soluble in body fluid, depending on the pH of the environment

Question 16

Ion-Exchange Resins

Answer 16

1) Resin-drug complex is prepared and may be tableted, encapsulated or suspended in aqueous vehicle
2) Drug release depends on pH and electrolyte concentration in the GI tract

Question 17

Osmotic Pump

Answer 17

System composed of a core tablet surrounded by a semi-permeable membrane coating having a 0.4 mm diameter laser-produced hole through which drug is released by osmotic pressure