Long Acting Implants

Question 1

What are the benefits of Long acting implants?

Answer 1

-improved patient compliance: reduce frequency of dosing and improved therapeutic outcomes
-Sustained drug delivery: stable plasma levels maintained or over an extended period
-Reduced healthcare burden
-Tailored treatment options
-Better disease management

Question 2

What is a monolithic device?

Answer 2

Most common
Single solid piece of material containing the drug
Simple to make via moulding
The drug diffuses out or the polymer erodes if biodegradable
Surgically administered and removed

Question 3

What is a reservoir system?

Answer 3

Drug is encapsulated in a shell. Reservoir may be in separate compartment or maybe a porous matrix.
Drug loaded as a solution suspension or solid
More complex manufacture
Surgically administered and removed

Question 4

What is a risk of using a reservoir system?

Answer 4

Drug dumping

Question 5

What is an in situ forming implant?

Answer 5

drug is dissolved in the polymer
Solution to gel transition
If PLGA is used it is biodegradable - releases drug whilst degrading
No surgery
Cost effective
Example is in the eyes

Question 6

What is an osmotic pump?

Answer 6

It has a semi permeable membrane ,an osmotic agent and an orifice (hole)
Can be subcutaneous or intratumour
An example is the Azlet system - Osmotic layer swells to release drug
Drug loading is limited as there are many agents involved
Surgically administered and removed

Question 7

What is a refillable implant?

Answer 7

A solid device made of metal or resistant polymer
With one or more chambers to release one or more drugs
Drug release via membrane
Refilled by hypodermic syringe and needles
Surgically ministered and removed
Delivery stopped by removal

Question 8

What is an example of a long acting contraceptive?

Answer 8

Nexplanon
Three-year contraceptive
Subcutaneous
Polymer is PEVA
Non-biodegradable

Question 9

What are characteristics of PEVA?

Answer 9

Well tolerated by the body
Offers controlled drug release
Flexible and durable
Has radio capacity - can be visible on x-ray
Easy to manufacture by moulding
Non-biodegradable

Question 10

What is an example of an ocular implant?

Answer 10

Ocusert
The drug is pilocarpine
One week release
Used for glaucoma
Prevents the need for multiple eyedrops
Under lower eyelid

Question 11

What is an example of pre-exposure prophylaxis implant?

Answer 11

Dapi ring
Neutralises HIV particles
For one month