Formulations

Question 1

Describe drug formulation

Answer 1

Taking a given drug and helping it reach its target tissue to optimise efficiency
Non-drug components - excipients
Formulation improve solubility for IV drugs
Improve drug stability in pills
Reduce number of doses required for pill
Modify delivery of a drug
Reduces side effects

Question 2

What are the drug formulations

Answer 2

Sublingual
Topical (skin)
rectal
Inhalation (inhalers)
Intranasal (nose)
Ocular (eye)
Vaginal
Otic (ear)
Intravenous
Subcutaneous
Intramuscular

Question 3

Why do side effects occur

Answer 3

When the drug travels to non-target tissues

Question 4

What happens if a drug doesn’t dissolve in the blood

Answer 4

Can cause blood clots - IV must be soluble before injection

Question 5

What happens if a drug doesn’t dissolve in the stomach

Answer 5

Bioavailability = 0

Question 6

What is a polymorph

Answer 6

Different molecular arrangements of the same atom or molecule

Question 7

What is the influence of crystal form

Answer 7

Affect solubility in gastrointestinal tract - ensure consistently one crystal form

Question 8

Describe the relationship between particle size and drug solubility

Answer 8

Small particles dissolve faster than larger particles
Drugs only enter blood in soluble form
Drug dissolution directly related to particle surface area
Smaller particles dissolve faster (increased absorption)

Question 9

Describe causes of poor patient adherence

Answer 9

Family and social support
Employment status
Cost of drug/treatment
Complexity of the therapeutic regiment and duration
Past failures
Adverse events
frequent dosing
High number of prescribed medications
Drug formulation or poor taste

Question 10

How can organoleptic properties improve patient adherence

Answer 10

Pills look, smell, taste and feel
Coatings with no or pleasant taste

Question 11

How do fixed dose combinations improve patient adherence

Answer 11

Multiple drugs combined to reduce number of pills to take

Question 12

Describe extended release formulations

Answer 12

attain consistent drug levels in plasma
- reduced variability
- improves patient adherence

Question 13

Describe the ideal formulation

Answer 13

Zero order release - released at a consistent rate over time to match the rate of metabolism and excretion - allows consistent plasma drug levels in therapeutic window

Question 14

Describe the effect of salt forms

Answer 14

Extended release - modified to control drug dissolution

Question 15

What can counterions affect

Answer 15

logP, dissolution and molecular weight
(Sodium, ethylamine, ethylenediamine, dimethylamine, trimethylamine)

Question 16

Describe extended release formulations

Answer 16

Dissolution-controlled reservoir systems - dispersed within polymer coating and immediately releases drug
Dissolution-controlled matrix system - dispersed through polymer matrix and release as it dissolves

Question 17

Describe confusion-controlled systems

Answer 17

Solid drugs dispersed with hydrophilic powder in insoluble particle coating or matrix - forms gel - slowly diffuses out of coating or matrix

Question 18

Describe osmotic pump formulation

Answer 18

Insoluble, impermeable polymer shell - hole laser-drilled to create orifice - hydrophilic hydrogel in shell - water enters and causes swelling and pushes drug molecules out