Drug delivery systems

Question 1

What 5 things are to be considered when determining dosage regime?

Answer 1

• Any renal/hepatic failure
• The recommended doses
• Age & weight
• Disease to be treated
• Drugs Toxicity
• starting dose and increased dose needed to achieve the desired effect

Question 2

Where are oral meds absorbed into systemic circulation?

Answer 2

GI tract

Question 3

Define a suspension:

Answer 3

Coarse drug particles in a liquid phase

Question 4

What type of drugs are used in suspension?

Answer 4

Insoluble & unpalatable drugs

Question 5

What type of patients would use solutoins/suspensions over tablets?

Answer 5

People with swallowing difficulties including the very young & old.

Question 6

How are solution & suspensions delivered?

Answer 6

By naso-gastric or Peg tubes

Question 7

What is the rate limitng step in tablet absorption?

Answer 7

The tablets break down or “dissolution”

Question 8

What are the main advantages of tablet/capsule drugs?

Answer 8

• convenient
• accurate doses
• easily reproduceable in mass
• high drug stability

Question 9

Why would you use an enteric coating on a tablet?

Answer 9

• to protect it from destructive stomach acid (Allowing it to reach the small intestine)
• to protect the stomach from a toxic drug,

Question 10

What drugs are enteric coated & why?

Answer 10

Omeprazole, to protect it from stomach acid

Aspirin to protect the stomach from it.

Question 11

Why don’t enteric coated tablets disintegrate till they reach the small intestine?

Answer 11

They only disintegrate in higher pHs, the stomach is very acidic so theyre unchanged in it.

Question 12

What are the advantages o prodrugs?

Answer 12

• avoid drug degradation in the gut

- prolongation of duration of action

Question 13

What does a prolonged release formulation do?

Answer 13

-contains more of the active drug but releases it more slowly over a prolonged period.

Question 14

How does usin prolonged release formulations improve patient compliance?

Answer 14

Prolonged release formulations need less frequent doses, increasing the odds a patient will take them all

Question 15

n what 3 forms do prolonged release formulation geerally come?

Answer 15

Oral tablets
Intramuscular Injection
Surgical implants

Question 16

What drugs are delivered by surgical implant?

Answer 16

Progesterone (contraception)

Testosterone

Question 17

Why drugs are ideal for buccal/sublingual administration?

Answer 17

Those with a large pre-systemic or first pass metabolism

Question 18

Do rectally delivered drugs treat locally or systemically?

Answer 18

Rectally delivered drugs can treat both local & systemic conditions

Question 19

For what type of patient are rectal route drugs useful?

Answer 19

those unable to swallow

Question 20

In what forms do rectal drugs come?

Answer 20

As creams
Liquids
Suppositories

Question 21

Do drugs delivered vaginally treat locally or systemically?

Answer 21

Vaginal route drugs treat local disease

Question 22

In what form are most vaginal route drugs?

Answer 22

Creams

Question 23

For what type of patient are IV drugs especiall useful?

Answer 23

Unconscious or comatose patients

Question 24

Why is IV good for drugs with short half-lives?

Answer 24

Allows constant infusion of them so the drug level remains within the therapeutic range.

Question 25

Are IV drugs rapid or slow release?

Answer 25

rapid systemic effects

Question 26

For what type of drugs is IV delivery especially useful.

Answer 26

Short half life drugs

And drugs with a narrow therapeutic index.

Question 27

what type of drus are delivered intramuscularly>

Answer 27

Insoluble drugs or those fomrualted in an oil base

Question 28

Examples of drugs given by subcutaenous injection?

Answer 28

HEparin
Insulin
Narcotic Analgesics

Question 29

How long do intramuscular injected drugs work?

Answer 29

Drugs injected intramuscularly can have sustained durations of up to months

Question 30

You cant see a patients veins but desperately need to deliver fluid what method do you use?

Answer 30

Subcutaneuous injection

Question 31

In what ways are subcutaneous injections deivered?

Answer 31

• Dermojet (needles)
• Solid pellet implanteed below skin
• Pumps (e.g. insulin pump)

Question 32

Drug is delivered via an adhesive patch on the skin, what delivery method is this?

Answer 32

Transdermal delivery

Question 33

How are transdermal drugs absorbed into circulation?

Answer 33

They cross skin by percutaneous absorbtion

Question 34

What is percutaneous absorbtion?

Answer 34

Absorption of a substance through unbroken skin

Question 35

Are transdermal drugs used for local or systemic effect?

Answer 35

Transdermal drugs can be systemic or local

Question 36

Are inhalation drugs used for local or systemic efects?

Answer 36

• Inhalation drugs have local effects.

- Only inhaled anaesthetics are systemic.

Question 37

Why are inhalation drugs useful?

Answer 37

Drugs are delivered direct to site of action with rapid effect & no first pass metaolism.

Question 38

Why do inhaled drugs only need small doses?

Answer 38

Only around 5-10% is absorbed systemically so the dose doesnt need to account for absorbtion or metabolism.

Question 39

Are inhaled drugs more less toxic?

Answer 39

Administering drugs by inhalation actually has a reduced adverse effect

Question 40

Name 4 carier based systems:

Answer 40

• Monoclonal antibodies
• Liposomal carriers
• Nanoparticles
• Genetic transfer systems

Question 41

What do monoclonal antibodies do?

Answer 41

• Monoclonal antibodies bind to cancer-specific antigens.

- Then produce induced immunological respones against the cancer

Question 42

What is a liposomal carrier?

Answer 42

A liposome packed with drugs, transports the trhough the blood

Question 43

How do liposomal carriers affect the drugs pharmacokinetics?

Answer 43

Drugs carried by liposomes acummulate at disease sites & have reduced distribution at senditive tissue

Question 44

Whats the main benefit of nanoparticle carriers?

Answer 44

Allow specific targeting/delivery of drugs.

Question 45

What effect do nanoparticles have on treatment?

Answer 45

The drug has reduced toxicity while maintaining therapeutic efficiency (beacue its targeted)

Question 46

What type of organisms are used as vectors for genetic transfer?

Answer 46

Viruses

Question 47

How are viruses altered for genetic tranfer systems?

Answer 47

The virus has the genes for viral replication removed and the therapeutic genes inserted.

Question 48

What does a genetic transfer system do?

Answer 48

The altered virus delivers the therapeutic gene to target cells.

Question 49

What do the different drug formulation allow?

Answer 49

A treatment regime to be tailored to a:

• patients needs
• pharmacological characteristics
• disease state

Question 50

Why are drug delivery systems formulated?

Answer 50

• to allow selective targeting to tissue site
• to avoid pre- or systemic metabolism
• to allow a 24 hour action

Question 51

what are the 4 ways drugs are deliverd?

Answer 51

-oral
-injection
0transdermal
-carrier based

Question 52

What are the three factors we used to determine which type of drug delivery system to use?

Answer 52

• dose of the drug to be given
• frequency of admiistration
• timing of administratin

Question 53

Examples of oral deliver systems?

Answer 53

• solutions and suspensions
• capsules
• tbablets
• modified release tablets

Question 54

Why are prolonged drugs useful?

Answer 54

• Most disorders require prolonged therapy
• Maintains drug levels within a therapeutic range over a longer period
• reduces the need for frequent dosing