Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmaceutics 2 Winter Final > 5 - Parenteral > Flashcards

5 - Parenteral Flashcards

1
Q

Why is the IM route often chosen over other parenteral routes?

A
  • Relative simplicity

- Lack of need for specially trained personnel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the common routes of parenteral administration?

A
  • Intravenous
  • Intramuscular
  • Subcutaneous
  • Intradermal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are advantages to IV administration?

A
  • Fastest onset of action b/c drug is injected directly into systemic circulation
  • No lag time for drug to be absorbed
  • Provides 100% bioavailability
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the difference between bolus and infusion?

A
  • Bolus = dose given all at once over short period of time; Cmax achieved almost instantaneously
  • Infusion = drug injected into vein over sustained period; may be intermittent where dose is administered at timed intervals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When and why is a loading dose given? What are examples of drugs that require loading dose?

A
  • For drugs w/ short half-life and narrow therapeutic window
  • Given to achieve therapeutic serum levels faster
  • Ex: heparin, lidocaine (desirable for serum levels to remain constant); nitroglycerin, dopamine (dose adjustments made according to px response)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are some reasons to choose IV route over oral?

A
  • Drug is subject to first-pass metabolism or destroyed in GI tract
  • Drug not absorbed via GI tract
  • Poor oral absorption and drug is a vesicant (causes blistering)
  • Dose too high to give orally
  • Rapid response is required
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are problems w/ the IV route?

A
  • Some drugs given too rapidly may cause toxicities

- For some products, excipients like alcohol or propylene glycol may be a problem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which drugs are solubilized using propylene glycol (PG)? What is the problem w/ PG?

A
  • Lorazepam, phenytoin, pentobarbital, and digoxin

- Infants can’t metabolize and excrete PG efficiently, so repeated dosing of these may lead to toxicity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are side effects of propylene glycol?

A
  • CNS toxicity
  • Hyperosmolarity
  • Hemolysis
  • Cardiac arrhythmia
  • Seizures
  • Agitation
  • Lactic acidosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the common sites of IM injections?

A
  • Deltoid
  • Gluteus
  • Lateral thigh
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why does the IM route produce a longer time to onset of action than IV?

A
  • Drug must move from muscle to systemic circulation

- Distribution to circulation is diffusion controlled

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What affects the rate of absorption of IM injections?

A
  • Local blood flow

- Injections to deltoid have faster onset of action than injections to gluteal muscle b/c deltoid has better blood flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What affects volume of absorption of IM injections?

A
  • Site of injection
  • Gluteal muscles can absorb 4-5 mL
  • Deltoid muscle can absorb 2-3 mL
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How are water soluble drugs and water insoluble drugs formulated?

A
  • Water soluble = aqueous solutions; distribute fairly quickly after injection
  • Water insoluble = dissolved in fixed oils; stay at site of injection and slowly release drug as vehicle is metabolized
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the depot formulation? What is it used for?

A
  • Water insoluble drug + fixed oil (ex: ester or oil-soluble salt dissolved in fixed oil)
  • Used to maintain therapy through prolonged release
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is an example of a depot formulation?

A
  • Fluphenazine, antipsychotic

- Depot formulation allows dosing every 2-6 weeks depending on px response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is an example of depot injections formulated as an aqueous suspensions? How does it work?

A
  • Penicillin G benzathine / penicillin G procaine w/ carboxymethylcellulose as suspending agent
  • Insoluble drugs hydrolyzed in tissues, releasing free penicillin G which is absorbed systemically
18
Q

Where are subcutaneous injections administered?

A

Into fatty tissue layer just below epidermis and dermis

19
Q

What is the max volume of SC injections? What happens if this volume is exceeded? Which drugs does it deliver?

A
  • Max = 1.5 mL; over 2 mL associated w/ various issues including injection pain and injection site leakage
  • Delivers protein biopharmaceuticals
20
Q

What happens if a drug given SC requires a high dose?

A

Must use a concentrated solution

21
Q

What affects the stability of SC injections? Why?

A
  • Protein concentration

- Increases chance for aggregation and particle formation during shelf-life

22
Q

Are SC injections absorbed slower or faster than IM injections? Why?

A
  • Slower

- Less blood flow to fatty tissue below the skin than to muscle

23
Q

Which drugs are often given by the SC route?

A
  • Insulin
  • Growth hormone
  • Heparin
  • Various vaccines
24
Q

What are the systems used for drugs where toxicity and/or delivery to site is problematical?

A
  • Liposomal systems

- Polymeric systems

25
Q

What are liposomes?

A

Closed spherical vesicles made of phospholipid bilayer where drug is encapsulated either in the cavity or wall structure

26
Q

What happens when liposomes are administered orally?

A

Destroyed by stomach acid, bile acids and enzymes of GI tract

27
Q

Which types of drugs can liposomes encapsulate?

A
  • Both lipophilic and hydrophilic

- Lipophilic inserted into bilayer membrane and hydrophilic in aqueous center

28
Q

What are advantages of liposomal systems?

A
  • Biocompatibility
  • Ability to carry large drug payloads
  • Can be modified to control biological characteristics through surface modification w/ polymers and ligands
  • Protect compounds from early inactivation, degradation and dilution in circulation
29
Q

Are liposomes active? Do they produce toxicity?

A

Inactive and minimal toxicity b/c composed of natural phospholipids

30
Q

What are the 4 key types of liposomal delivery systems?

A
  • Conventional liposomes
  • Sterically-stabilized liposomes
  • Ligand-targeted liposomes
  • Combination of previous
31
Q

What are conventional liposomes?

A
  • Lipid bilayer that can be composed of cationic, anionic, or neutral (phospho)lipids and cholesterol enclosing aqueous center
  • Reduce toxicity of compounds by modifying PK and biodistribution to enhance drug delivery to diseased tissue
  • Prone to rapid elimination from bloodstream due to uptake by fixed macrophages of reticuloendothelial system (RES), mainly in liver and spleen
32
Q

What are PEGylated liposomes? What are they used for? What is a disadvantage to this?

A
  • Improve stability and prolong circulation times in blood
  • Hydrophilic polymer (PEG) used to obtain sterically-stabilized liposomes, which slow uptake by RES thereby prolonging blood residence time, providing accumulation at pathological sites, and attenuating SE
  • Can reduce ability to interact w/ intended targets
33
Q

How do ligand-targeted liposomes work?

A

Offer site-specific delivery of drugs to designated cell types which selectively express or over-express specific ligands (like receptors or cell adhesion molecules) at site of disease

34
Q

What are the possible ligands for ligand-targeted liposomes?

A

Antibodies, peptides/proteins, and carbs

35
Q

Contrast the outer membrane surface of conventional, PEGylated, and ligand-targeted liposomes

A
  • Conventional = negatively and positively charged lipids
  • PEGylated = PEG attached to hydrophilic heads of membrane
  • Ligand-targeted = receptors for common ligands (proteins, antibodies, carbs) attached to PEG which is attached to hydrophilic head of membrane
36
Q

Describe the doxorubicin liposome injection. When is it used?

A
  • Doxorubicin encapsulated in PEGylated liposomes
  • Various types of cancer; found to be effective alternative to conventional doxorubicin in px w/ pre-existing cardiac dysfunction
37
Q

What is the benefit to a doxorubicin liposome injection?

A

Doxorubicin in PEGylated liposomes minimizes uptake and clearance by RES, prolonging serum and plasma half-life and allows drug to accumulate in tumour tissue rather than non-target healthy tissue

38
Q

Which side effect is reduced w/ the amphotericin-B liposome injection?

A

Renal toxicity

39
Q

What determines drug release from IM or SC depot injections?

A

Diffusion or erosion of polymer matrix

40
Q

What are commonly used synthetic biodegradable polymers?

A
  • Polyesters (most common; PLA, PGA, and PLGA w/ PGA releasing drug the fastest)
  • Polyanhydrides
  • Polyamides
41
Q

What is leuprolide acetate? When is it used?

A
  • Microsphere formulation where drug is embedded in matrix of PLGA
  • Used in men to treat symptoms of prostate cancer and in women to treat sx of endometriosis or uterine fibroids
42
Q

What is paclitaxel used for?

A

Tx of metastatic breast cancer

Pharmaceutics 2 Winter Final (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions