Formulation of Advanced or Complex Medicines 30 Flashcards
How does ultrasound work to deliver drugs?
Low frequency ultrasound creates cavitation, increasing permeability
- may also act as a physical adjuvant for transcutaneous immunisation
How does an abrasive patch work to deliver drugs?
Skin is pre-treated with an abrasive strip prior to patch application
Antigen and/or adjuvants are delivered to the skin immune cells
Demonstrated efficacy and safety in more than 35 clinical trials
- including seasonal and pandemic influenza
Microdermabrasion works in a similar way
- physical exfoliation
What are microneedles?
Needle or needles less than 1mm in length
Vary in height, sharpness, width, spacing
Hollow, solid, cone, cylinder, pyramid, blade
Silicon, metal, glass, polymer, carbohydrate
What are the four different methods of drug delivery with microneedle arrays?
Poke and patch
- remove needles and apply patch
Coat and poke
- drug on surface of the needles
- leave needles in place for drug to dissolve
Poke and dissolve
- needles stay in the body and dissolve
Poke and release
Give two examples of non-biodegradable polymer implants
Reservoir device
Matrix device
Describe the reservoir in non-biodegradable polymer implants
Drug surrounded by rate controlling polymer membrane
Drug release governed by diffusion
Water influx initiates drug release
Release depends on membrane and drug properties
Give examples of the polymer membrane that are in non-biodegradable polymer implants
Silicones
EVA
- ethylene vinyl acetate
Copolymer
Describe the matrix in a non-biodegradable polymer implant
Drug dispersed in polymeric matrix
Drug release governed by diffusion
Release decreases over time
- drug depleted boundary
Give examples of polymers used in matrix non-biodegradable polymer implants
Silicone rubbers
Methacrylates
Give two examples of biodegradable polymer-based depot formulations used parenterally
Controlled release polymer matrices designed to give zero order release over weeks to months
- rods
- microparticles
Controlled release but also local delivery
- polymer-matrix discs
What are the advantages of using biodegradable polymer based depot formulations used parenterally?
Can be left in situ as they can be absorbed into the body
What is the mechanism of action of Goseriline acetate (Zoladex) and leuprolide acetate (Lupron)?
They are LHRH analogues
- they act on the LHRH receptors in the pituitary gland, the same way as natural gonadorelin
Initially, goserelin causes an increase in the amount of FSH and LH released from the pituitary gland
Chronic administration of goserelin desensitises the pituitary gland
- it produces less and less FSH and LH
- stops the production of oestrogens in the female
- stops the production of androgens in the male
Reduction in the levels of sex hormone can be exploited to treat disorders that are linked to levels of oestrogen or testosterone
What is the difference in formulation between goserelin and leuprolide?
Goserelin is a rod
Leuprolide is a microparticle
What factors affect the release rate of goserelin and leuprolide?
Particle size
Drug loading
What are the advantages of polymer depot formulations for controlled release?
Can be used as a CR depot to maintain plasma concentrations over long period
Easy to administer
Good patient compliance
