Drug Delivery Systems Flashcards
What are different kinds of drug delivery?
Oral
Intravenous (IV)
Transdermal
Carrier based
What are different forms of drugs that may be given to patients?
Tablets or capsules
Solutions or suspensions
Ointments and creams
Inhalation
Injections
Suppositories (insterted into rectum or vagina)
Pessaries (inserted into vagina)
What are soppositories?
Drugs that are inserted into the rectum or the vagina
What are pessaries?
Drugs that are inserted into the vagina
What are things that determine which drug delivery system to use?
Dose of the drug being given
Frequency of administration
Timing of administration
Disease being treated
What do we consider when deciding what dose to use?
Recommended dose
Impaired renal function
Impaired liver function
Age and weight
Disease to be treated
Drug toxicity
What is oral medication absorbed by?
The GI tract:
Buccal
Sublingual
Oral
Rectal
What are solutions and suspension useful for?
Giving medicine to the young, elderly and patients with swollowing difficulties
What is an advantage of using solutions or suspensions?
Absorbed extrememly rapidly
What does the absorption of solutions or suspensions depend on?
Gastric emptying and is more rapid from the small intestine
Where is absorption from solutions or suspensions most rapid from?
Small intestine
What is the rate limiting step for the absorption of tablets?
Dissolution (tablet breakdown)
What are the advantages of using tablets or capsules?
Convenience
Accuracy of dose
Reproducibility
Drug stability
Ease of mass production
What do enteric coated tablets do?
Delay the disintegration of the tablet until it reaches the small instestine
Why would enteric coated tablets be used?
Protect the drug from stomach acid
Protect the stomach from the drug
What are prolonged release formulations useful for?
Most disorders required prolonged therapy
Maintains drug level within a therapeutic range
Reduces the need for frequent dosing
Compliance is improved
What kind of therapy do most disorders require?
Prolonged therapy
What are different kinds of prolonged release drugs?
Oral preparations
Parenteral preparations (intermuscular injections)
Surgical implants
What can you not do when using prolonged release drugs?
Swap someone from one form to another
What are prodrugs?
Synthesised inactive derivatives of an active drug which requires to be metabolically activated after administration
What are the advantages of using prodrugs?
Prolongation of duration of action
Avoidance of the drug in the gut
What are buccal and sublingual adminstration ideal for?
Drugs which have an extensive first pass metabolism
What are sublingual tablets?
Ones which dissolve slowly under the tongue
Who is the rectal route often used for?
Young
Old
Patients unable to swollow
What is an advantage of using the rectal route?
Bypass first pass metabolism
How may drugs from the rectal route act?
Locally
Systematically
How do drugs from the vaginal route act?
Locally
What do drugs from the vaginal route include?
Creams
Pessaries
What do injection based drug delivery systems include?
Intravenous (IV)
Intramuscular
Subcutaneous
Intradermal
What do injection based drugs provide?
Fast systematic effects by bypassing first pass metabolism
What can you say about the half life of injection based drugs?
Short half life
What is useful about the infusion on injection based drugs?
Can be infused continuously
What kinds of patents who are not able to swollow drugs can injection based drugs be given to?
Unconscious ones
When are drugs given intravaneously?
Rapid onset of action is required
Careful control of plasma level is required
Drug has a short half life
How may IV formulations be given?
Rapidly
Slowly (prevent toxic effects)
Continuous infusion to ensure acurate control
Why would an IV drug be infused slowly?
To prevent toxic effects
Why would an IV drug be infused continuously?
Ensure accurate control
What is an intramuscular injection?
Injection given into muscle mass
What is an advantage of intramuscular injection?
Allows more sustained duration of action up to months
What is a subcutaneous injection?
Injection applied under the skin
What is the advantage of a subcutaneous injection?
Bypass the nedd for venous access
What are transdermal drug delivery systems?
Adhesive patches containing the drug are applied to the skin where the drug then crosses the skin surface by diffusion and enters systematic circulation
What is an advantage of transdermal drug deliver systems?
Bypass first pass metabolism
What does inhalation drugs do?
Delivers drugs directly to the things for local effect or to achieve systematic effect
What is an advantage of inhalation drugs?
Rapid effect using smaller doses so less side effects
What does utilising carriers allow?
Small amounts of drugs to be administered and to be taken to where they are needed
What are examples of pharmaceutical carriers?
Micelles
Vesicles
Multifunctional dendritic polymers
Nanospheres
Nanocapsules
Liquid crystals
Why does the colour of a drug have an impact on its effect?
The placebo effect
