L13: Getting drug to its site of action

Question 1

drug delivery

Answer 1

‘The method and route used to provide
medication’
– ‘The means by which a safe and efficacious
medicament is delivered in order to elicit a pre-
defined clinical response’
– Drug has to enter the body and distribute at the
right tissue at the right time

Question 2

drug or medicine

Answer 2

Drug or Medicine
Drug= Active Pharmaceutical Ingredient (API)
Most likely small molecular weight (ca 300-600) organic species
(synthesised by medicinal chemist)
or possibly peptide or oligonucleotide
(prepared by biotechnological means)
Medicine = API plus excipients
Excipients are materials should be inert and safe
– sole function is to act as a carrier or platform for the API

Question 3

some common problems

Answer 3

• SOME COMMON PROBLEMS
  – ROUTE??
• A drug that requires to be distributed to its active site via the systemic
  circulation is not orally absorbed
• E.g. Beclomethasone Dipropionate
  – Inhaler
  – Cream
  SOME COMMON PROBLEMS
  – ROUTE
• Patient compliance is low e.g. diabetes due to non patient friendly
  administration
• Reformulate into another drug delivery device
• Improves therapy
  STABILITY
• Active Pharmaceutical Ingredient may be physically or chemically unstable
• Excipient stabilisation
• Enhances shelf-life stability
  DOSING
• Drug may have a short
  half-life
• Controlled or extended
  release may be
  required
• Reduce dosing
  frequency
• Enhances half life

Question 4

the path to drug delivery

Answer 4

• Understand the chemistry of the molecule
• Appreciate the pharmacology of the disease
• Consider the patient and the target tissue
  – Patient needs
• Elderly
• Toddlers
• Babies
• Chronic vs acute
• Severity
• Chronopharmacology
• Design, manufacture and test a drug delivery system to achieve your aim i.e.
  provide clinical benefit for a patient