exam revision Flashcards
(34 cards)
Delayed Release
products coated and designed to pass through the stomach and only release within the INTESTINAL tract
Extended Release
Products designed to release medication in a controlled manner at a pre-determined rate, duration and location. Helps achieve and maintain optimum therapeutic blood levels of drug
What are the main advantages of Modified Drug release system?
- Less fluctuation in drug blood levels
- Frequency reduction in dosing
- enhanced convenience and compliance
- Reduction in ADRs
- Reduction in overall health cost
What are the disadvantages of Modified drug release?
- loss of flexibility
- dose dumping
- constraints on the types of drugs that suitable for the candidates
- limits the max period (approx. 12 hrs)
What are the 8 extended release technologies?
- Coated beads, granules, microspheres
- Multitablet system
- Microencapsulated drug
- Hydrophilic matrix systems
- Insoluble polymer matrix
- Complex Formation
- Ion Exchange resins
- Osmotic pumps
Delayed release of drug can be intentional till the intestines as it ensures:
- protection of drug from gastric fluids
- reduces gastric distress caused by the drug
- facilitating GI transit for drugs that are better absorbed from the intestines.
What are the 3 dependeds for enteric coating?
- pH
- time
- enzyme
What is repeat action? (Repeatabs)
Initial dose of drug is released immediately and a second dose follows later
What type of condition is repeat action used for?
- chronic conditions that require repeat doses
- Two layers may have one layer for immediate release with a second layer releasing drug later in an extended manner
How are targeted release drugs absorbed?
- colonic drug delivery which are only digested by colonic bacteria.
What are some clinical considerations to consider for modified drug release?
- should not use modified release products interchangeably with immediate release forms of the SAME drug
- patients who are stabilised on modified release product should not be changed as different extended release drugs can have different characteristics
- not to be crushed or chewed
- nasogastric tubes
What is transdermal drug delivery?
passage of therapeutic quantities of drug through the skin and into general circulation
What are the factors affecting percutaneous absorption?
- increase in drug concentration
- larger area of application
- drugs with a MW 100-800 with aqueous and lipid solubility
- has greater physiochemical attraction to the skin than vehicle
- Drugs generally penetrate better in their unionised nonpolar/lipophilic
- duration
- site
What are the advantages of Transdermal Drug Therapy?
- avoids GI drug absorption
- oral route is unsuitable as with vomiting and diarrhoea
- Avoids first-pass effect
- Non-invasive
- extended therapy with single application
- activity of drugs with shorter half-life
- terminated rapidly
- easily and rapidly identified
What are the main disadvantages of transdermal Drug Therapy?
- Relatively potent drugs are suitable due to natural limits of drug entry imposed via skin’s permeability
- Contact dermatitis
How is bioavailability of transdermal drug maximised?
- pro-drugs
- chemical potential adjustment
- hydration
- ion pairs
- ultrasound
- iontophoresis
- electroporation
- Stratum corneum removal
- photomechanical wave
- needleless injection
- needle array
- liposomes
- penetration enhancers
What is the structure of transdermal patch?
- protective layer
- adhesive layer
- backing layer
Where is the drug mainly located in a transdermal patch?
- adhesive layer
- contains the loading dose and penetration enhancers.
What occurs in the matrix system?
separate matrix to increase drug content and control release.
What is rate-limiting membrane system?
- contains drug in a reservoir with release controlled through a semipermeable membrane
What are some clinical considerations for Transdermal patch?
- rotate locations
- site of application
- clean, dry skin
- sensitivity
- cutting the patch may destroy its integrity
What types of drugs can be delivered via Transdermal?
- testosterone
- anti-inflammatories
- promethazine
- veterinary applications
- oestradiol
- nicotine
What are the implantable drug delivery systems types?
- nonbiodegradable implants via diffusion
- biodegradable implants which release via surface or bulk degradation
- mini pumps
- stents
- bioresponsive
What are the advantages of implantable drug delivery?
- convenience
- compliance
- controlled release
- intermittent/bio-responsive release
- improved drug delivery
- flexibility
- commercial advantages
