Drug Delivery Systems

Question 1

Name the type of drug delivery systems available

Answer 1

Oral
Injection based
Transdermal
Carrier based

Question 2

In what forms/formulations can drugs be given to patients (7)

Answer 2

Tablets or capsules
Solutions or suspensions
Ointments and creams
Inhalation
Injections
Suppositories
Pessaries

Question 3

What types of tablets/capsules are there

Answer 3

Regular
Modified release
Prodrugs
Enteric coated

Question 4

How can a drug delivery system be formulated

Answer 4

To allow selective targeting of a tissue site
To avoid pre- or systemic metabolism
To allow a 24 hour action

Question 5

What do drug formulations allow

Answer 5

A treatment regime to be tailored to a patients needs, pharmacological characteristics and disease state

Question 6

What determines the drug delivery system used

Answer 6

The dose of the drug to be given
The frequency of administration
The timing of administration

Question 7

What should be considered when choosing a dosage regime (7)

Answer 7

Find out the recommended dose (BNF/BNFc)
Is there impaired renal function
Is there impaired hepatic function
Age and weight
Disease to be treated
Drug toxicity
Give a starting dose and increase dose to achieve the desired effect

Question 8

What are commonly used oral delivery systems (5)

Answer 8

Solutions
Suspensions
Capsules
Tablets
Modified release tablets

Question 9

Where is absorption through using oral delivery systems

Answer 9

GI tract

Question 10

When are solutions and suspensions a useful form of administration

Answer 10

In the young, elderly and patients with swallowing difficulties

Question 11

How can solutions and suspensions be given

Answer 11

Through a nasogastric tube or PEG tube

Question 12

What is the rate of absorption for drugs administered through a nasogastric tube or PEG tube

Answer 12

Extremely rapidly

Question 13

What is absorption dependent on

Answer 13

Gastric emptying and is most rapid from the small intestine

Question 14

Describe suspensions

Answer 14

Dispersions of coarse drug particles in a liquid phase

The dose can be contained in a small volume

Question 15

What are suspensions good for

Answer 15

Drugs which are insoluble unpalatable as they are better tolerated

Question 16

What limits the rate limiting step in the absorption of tablets

Answer 16

Dissolution or tablet break down

Question 17

What are the advantages of tablets and capsules

Answer 17

Convenience
Accuracy of dose
Reproducibility
Drug stability
Ease of mass production

Question 18

What does the enteric coating of tablets do

Answer 18

It delays disintegration of the tablet until it reaches the small intestine

Question 19

Why are some tablets enteric coated

Answer 19

Protect the drug from stomach acid (e.g. Omeprazole)

Protect the stomach from the drug (e.g. Aspirin)

Question 20

Why are prolonged release formulations useful

Answer 20

Most disorders required prolonged therapy
Maintains drug levels within a therapeutic range
Reduces the need for frequent dosing
Compliance is improved
Improved nursing and doctor compliance

Question 21

How can the time course for a drug in the body be prolonged

Answer 21

By giving the drug in a form that has a slower but sustained rate of release
This type of preparation contains more of the active drug but releases it more slowly over a prolonged period

Question 22

Name some oral preparations

Answer 22

Verapamil
Diltiazem
Isosorbide mononitrate
Lithium
Carbamazepine

Question 23

Name some parenteral perparations

Answer 23

Intramuscular injections of flupentixol or risperidone

Question 24

Name some surgical implants

Answer 24

Progesterone contraception

Testosterone

Question 25

What are prodrugs

Answer 25

Synthesised inactive derivatives of an active drug which requires to be metabolically activated after administration

Question 26

What are the advantages of prodrugs

Answer 26

Prolongation of duration of action | Avoidance of degradation of the drug in the gut

Question 27

When are buccal and sublingual administration ideal

Answer 27

For drugs which have extensive pre-systemic or first pass metabolism

Question 28

What are sublingual tablets

Answer 28

Small and dissolve slowly under the tongue or in the buccal cavity (e.g. GTN)

Question 29

What can be administered through the rectal route

Answer 29

Suppositories, Creams and Liquids

Question 30

When is the rectal route useful

Answer 30

In the young or old | Patients unable to swallow

Question 31

Why may drugs be administered rectally

Answer 31

To treat local conditions such as proctitis | To achieve systemic absorption (indomethacin)

Question 32

How is the rectal drugs administered

Answer 32

As a suppository

Question 33

What is a benefit of the rectal route

Answer 33

Bypass pre-systemic metabolism

Question 34

What can be used through the vaginal route

Answer 34

Pessaries | Creams

Question 35

What do drugs administered through the vaginal route treat

Answer 35

Local disease

Question 36

What are the benefits of injection based drug delivery systems

Answer 36

Provide fast systemic effects bypassing first-pass metabolism Drugs can be administered in unconscious or comatose patients Drugs having short half-life can be infused continuously

Question 37

Name the three different methods of injection based drug delivery systems

Answer 37

Intradermal (10-15 degree angle) Subcutaneous (45 degree angle) Intramuscular (90 degree angle)

Question 38

When are drugs given intravenously

Answer 38

When: A rapid onset of action is required Careful control of plasma levels is required A drug has a short half-life

Question 39

How can IV formulations be given

Answer 39

Rapidly Slowly to prevent toxic effects Continuous infusion to ensure accurate control of blood levels especially when a drug has a narrow therapeutic index

Question 40

What is an intramuscular injection

Answer 40

An injection of the drug given into the muscle mass | They allow a more sustained duration of action up to months

Question 41

What type of drugs can be given intramuscularlly

Answer 41

Drugs insoluble or formulated in an oil base

Question 42

Give examples of intramuscular drugs

Answer 42

Depot injections contraceptive | Neuroleptics

Question 43

What is a disadvantage of the intramuscular injection

Answer 43

May be painful

Question 44

Describe the subcutaneous injection

Answer 44

A common route of administration | Easy to use and bypasses need for venous access

Question 45

Give examples of subcutaneous injections

Answer 45

Insulin Heparin Narcotic analgesics

Question 46

What is dermojet

Answer 46

It is a sub-cutaneous needleless injection used for mass inoculation

Question 47

What is a pellet implantation

Answer 47

Drug as a solid pellet is implanted under the skin to provide uniform systemic effect (e.g. testosterone)

Question 48

What us a transdermal drug delivery system

Answer 48

Adhesive patches containing the drug are applied on the skin

Question 49

How do drugs cross the skin surface in the transdermal drug delivery system

Answer 49

By diffusion by percutaneous absorption and goes into systemic circulation

Question 50

What does the transdermal drug delivery system bypass

Answer 50

First-pass hepatic inactivation

Question 51

What types of drug delivery systems have percutaneous administration

Answer 51

Creams Ointments Skin patches

Question 52

What is percutaneous administration

Answer 52

Drugs that can be administered to the skin to achieve a local effect (e.g. steroids) or a systemic effect (e.g. HRT or nitroglycerin)

Question 53

Describe skin patches

Answer 53

They allow the release of a drug from a reservoir into the skin and then into the systemic circulation Using skin patches it is possible to obtain controlled, sustained blood levels of the administered drug

Question 54

Give examples of skin patches

Answer 54

``` Nicotine Nitroglycerin Opiates HRT Contraception ```

Question 55

What is the hydrogel transdermal patch used for

Answer 55

In the treatment of burns

Question 56

What is the scoplamine (SCOP) patch used for

Answer 56

Motion sickness

Question 57

What are inhalation drugs commonly used to deliver

Answer 57

Drugs directly to the lung for local effect or to achieve a systemic effect (e.g. anaesthetics)

Question 58

How is inhalation medication administered

Answer 58

Pressurised aerosol Breath actuated aerosol Nebuliser Dry powder device

Question 59

What are the advantages of inhalation

Answer 59

``` Drug delivered directly to site of action Rapid effect Small doses used Little systemic absorption Reduced adverse effects ```

Question 60

What is a disadvantage of inhalation

Answer 60

Patient education is essential

Question 61

How can drug delivery systems be developed in the future

Answer 61

Drugs will be designed according to individual genotypes, so enhancing safety and efficacy

Question 62

Name the carriers in carrier based drug delivery systems (6)

Answer 62

``` Vesicles Micelles Liquid crystals Nanocapsules Nanospheres Multifunctional dendritic polymers ```

Question 63

How do monoclonal antibodies act in regards to cancer

Answer 63

Act directly when binding to a cancer specific antigen and induce immunological response to cancer cells

Question 64

How have monoclonal antibodies been modified

Answer 64

For delivery of a toxin, cytokine or other active drug

Question 65

What do pre-clinical and clinical liposomal packed drugs show

Answer 65

Reduced toxicities with enhanced efficiency

Question 66

What do altered pharmokinetics do to liposomal drug delivery

Answer 66

Drug accumulation at disease sites and reduced distribution to sensitive tissue (target delivery of drugs)

Question 67

What is nanoparticle based drug delivery

Answer 67

Drugs targeted to a precise location which would make the drug much more effective & reduce the chances of possible side-effects

Question 68

What are the benefits of nanoparticle based drug delivery

Answer 68

More specific drug targeting & delivery | Reduction in toxicity while maintaining therapeutic efficiency

Question 69

Name 3 nanocarriers

Answer 69

Nanoparticles Nanotubule Nanoshell

Question 70

When are carbon nanotubules used

Answer 70

Treatment of Bronchial asthma

Question 71

When are gold nanoparticles used

Answer 71

Cancer chemotherapy (free radical generation)

Question 72

What are nanoerythrosomes

Answer 72

Erythrocytes that can carry proteins, enzymes & macromolecules

Question 73

When are nanoerythrosomes used

Answer 73

Treatment of liver tumours, parasitic disease | & enzyme disease

Question 74

What is the genetic transfer system

Answer 74

When the natural virus has the genes for viral replication removed and therapeutic genes inserted This forms a virus carrying the therapeutic gene which infects and delivers the therapeutic gene to target cells

Question 75

What could the genetic transfer system potentially be used for

Answer 75

Adenovirus | HIV

Question 76

What is a dendrimer

Answer 76

A highly branched globular biodegradable synthetic molecule

Question 77

Describe the modified buckyball

Answer 77

They deliver radioactivity to the tumour (e.g. C-60 against CA colon) The transfer of radiation is within the ball hence it minimises strong radiation to healthy tissue