540 - Drug Delivery Systems - Exam Iii - Im And Sc Administration

Front 1

Describe what is entailed by intramuscular (IM) administration of a drug.

Back 1

A solution, suspension, or emulsion of drug in a syringe is injected by needle into a muscle.

Front 2

What is a bolus?

Back 2

A bolus is a concentrated dosage of a drug given in a single administration.

Front 3

Describe what happens when a bolus of a drug having low solubility is injected intramuscularly or subcutaneously.

Back 3

The injected bolus forms a depot that releases the drug over a period of time.

Front 4

What are two salient advantages of a depot injection versus other routes of administration, such as administering oral capsules or tablets?

Back 4

First, the sustained-release effect of a depot injection avoids high peak concentrations. Second, patient compliance is often a challenge with oral administration. Depot injections preclude the need for vigilant adherence to an oral dosing schedule on the part of the patient.

Front 5

Factors that influence IM or SC drug absorption can be divided into two general considerations. What are they?

Back 5

1) Characteristics of the drug, such as its solubility and dosage form, and 2) Physiologic factors, such as blood flow at the site of injection.

Front 6

What are three common sites of IM administration in the lower body?

Back 6

The buttocks, lateral thigh, and quadriceps are common sites of IM administration.

Front 7

What is one disadvantage of intramuscular (IM) or subcutaneous (SC) injections for some drugs?

Back 7

Some drugs are not fully absorbed following an IM or SC injection.

Front 8

What is the typical volume of an IM injection?

Back 8

2 to 5 mL

Front 9

What is the typical volume of an IM injection for an infant?

Back 9

0.25 mL

Front 10

What type of process is typical for the absorption of an intramuscularly administered aqueous solution? How long does it usually take?

Back 10

The absorption of an aqueous solution administered via IM injection is often a first order process and it usually occurs within 30 minutes.

Front 11

What range of blood flow rates, in mL/min, is typical of IM injection sites? On what variable does blood flow within this range most strongly depend?

Back 11

0.02 to 0.07 mL/min is the typical blood flow rate, depending on the level of muscle activity.

Front 12

What three factors are said to contribute to variability in injected drug absorption?

Back 12

1) Blood flow rate, which can be effected by exercise or disease, 2) Manner of injection, & 3) Dispersal

Front 13

Name three common intramuscular injection sites and rank the relative absorption rates (rapid, intermediate, or slow).

Back 13

1) Deltoid, i.e. shoulder (rapid), 2) Vastus lateralis, i.e. lateral thigh (intermediate), & 3) Gluteal muscle, i.e. butt (slow).

Front 14

Describe what is entailed by subcutaneous (SC) administration of a drug.

Back 14

A small volume bolus of drug in a syringe is injected by needle under the skin.

Front 15

What is the typical volume limit of an SC injection?

Back 15

2 mL

Front 16

Describe how and why the onset of action and the absorption rates of a SC injection differ from that of an IM or IV injection.

Back 16

Both the onset of action and the absorption rate of a SC injection is usually slower than with IM or IV injections because of the relatively low blood flow to SC tissue.

Front 17

What is the term for subcutaneous infusion of a large volume parenteral (LVP) fluid, at a relatively slow rate for a few days, in order to maintain adequate hydration of an elderly patient or to provide a continuous supply of a drug, e.g. for antibiotic treatment of a child.

Back 17

Hypodermoclysis (NOT hyperdermoclysis)

Front 18

What is the name of the enzyme that can be given as bolus, at the subsequent infusion site, to enhance fluid absorption via hypodermoclysis via temporarily lysing the normal interstitial barrier?

Back 18

Hyaluronidase

Front 19

Rank, from fastest to slowest, the relative absorption rate constants of the following, alphabetically-arranged preparations: aqueous solution, aqueous suspension, oil-in-water emulsion, oil solution, oil suspension, pellet implant, & water-in-oil emulsion

Back 19

The relative absorption rate constants, from fastest to slowest, are aqueous solution (min to hrs) > aqueous suspension > oil solution > oil-in-water emulsion > water-in-oil emulsion > oil suspension (weeks to months) > pellet implant.

Front 20

Name the process that dictates the capillary absorption rate for an aqueous solution of a drug from a site of IM or SC injection.

Back 20

Diffusion

Front 21

Describe the two processes that dictate the absorption rate for an aqueous suspension of a drug from a site of injection.

Back 21

First the suspended particles must undergo dissolution. Then the dissolved drug must reach capillaries via diffusion.

Front 22

Describe the two processes that dictate the absorption rate for an oil solution of a drug from an injection site.

Back 22

First the drug must partition from the oil phase into the aqueous phase. Then the aqueous form must reach capillaries via diffusion.

Front 23

What is represented the expression Ko/w?

Back 23

Ko/w is the equilibrium constant for the partitioning of a substance, such as a drug, between the oil and water, i.e. [drug] in oil / [drug] in water.

Front 24

What effect does a high Ko/w have on the rate of a drug’s release from an injection site via absorption from an oil solution?

Back 24

A high Ko/w prolongs the release of a drug from an oil solution by slowing its absorption rate.

Front 25

List four mechanisms by which an oil is cleared from a site of injection?

Back 25

1) Absorption through capillaries, 2) Lymphatic absorption, 3) Phagocytosis, & 4) Metabolism at the site of injection, followed via absorption of the metabolites.

Front 26

What is the major use of parenteral suspensions, in oil or water, injected intramuscularly or subcutaneously?

Back 26

Parenteral suspensions in oil or water provide a prolonged, sustained-release effect from a single dose.

Front 27

What is typically the rate limiting step in the absorption of a relatively insoluble drug formulated as a parenteral suspension in oil or water?

Back 27

The rate limiting step of a relatively insoluble drug, formulated as a suspension in oil or water, is its dissolution rate.

Front 28

What particle size range is considered the limit for a parenteral suspension of a drug, in oil or water, for intravenous injection? What other criterion must the particle meet?

Back 28

The size of a particle suspended in oil or water for IV injection must be less than 0.5 to 1.0 micron, and it must be biodegradable.