BIOL122 Lecture 1: BIOL122 notes weeks 1-10
NHPA’s
National Health Priorities Australia:
• Diseases and conditions that significantly contribute to the burden of illness and
injury in the Australian community
• Arthritis and musculoskeletal conditions
• Asthma
• Cancer control
• Cardiovascular health
• Diabetes mellitus
• Injury prevention and control
• Mental health
• Obesity
• Dementia
Pharmacokinetics:
Studies of movement of drugs within the body; i.e. drug absorption, distribution,
metabolism and excretion. How the body acts on drugs
Drug Absorption:
Passage of a drug from its site of administration into plasma: i.e., how does the drug get
into the blood?
Drugs must cross cell membranes: e.g. oral drugs cross mucosa and epithelial layers of the
GI tract.
How are drugs transported across the membrane?
- membrane openings (filtration): movement of particles distinguished by size of molecule
- passive diffusion: movement down gradient, no energy required
- active transport: movement against gradient, energy required
- carrier molecules: can be active or passive
Week 1:
find more resources at oneclass.com
find more resources at oneclass.com
What determines drug absorption?
1 Nature of absorbing surface
• Number of cell membrane layers, many vs few. E.g. skin vs under the tounge
• Surface area. Large vs small/ e.g. lungs have huge surface area
• Blood supply. Good vs poor. E.g. connective tissues such as tendons and ligaments
are poorly vascularised
2 Chemical structure
• Lipid solubility
• Degree of ionisation
• Molecular weight
• Dissolution rate
• pH of aqueous phase
charged molecules are not allowed to get through a plasma membrane, but water molecules
can eause its so sall. Drugs that dissolve well will be absorbed fast
Drug
distribution:
The movement of a drug from site of administration to tissues (via blood)
Many drugs exist in circulatory system bound to plasma proteins
find more resources at oneclass.com
find more resources at oneclass.com
Ol fee dugs a eet phaaologial effets
Determinants of drug distribution:
• concentration of free drug
• concentration of plasma proteins
• proportion of body fat and body water
• barriers: blood- brain and placenta
Drug bioavailability:
• proportion of administered dose that
reaches systemic circulation and is able to
exert its effects
• reported as percentage of administered dose
• Variable. (dependant on route of
administration, absorption, etc.)
Drug metabolism
Enzyme modification of drug molecules
Start of the elimination process
Hepatic biotransformation (liver)
• Beginning of drug metabolism by liver enzymes
• A process which converts lipid soluble drugs into water soluble products- can no
longer be absorbed- preparation for excretion
• Some drugs are activated after biotransformation. E.g. codeine, aspirin
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
National health priorities australia: diseases and conditions that significantly contribute to the burden of illness and. Nhpa"s injury in the australian community: arthritis and musculoskeletal conditions, asthma, cancer control, cardiovascular health, diabetes mellitus, mental health, obesity, dementia. Studies of movement of drugs within the body; i. e. drug absorption, distribution, metabolism and excretion. Drugs must cross cell membranes: e. g. oral drugs cross mucosa and epithelial layers of the. Membrane openings (filtration): movement of particles distinguished by size of molecule. Passive diffusion: movement down gradient, no energy required. Active transport: movement against gradient, energy required. Carrier molecules: can be active or passive. 1 nature of absorbing surface: number of cell membrane layers, many vs few. E. g. skin vs under the tounge: surface area. Large vs small/ e. g. lungs have huge surface area: blood supply. E. g. connective tissues such as tendons and ligaments are poorly vascularised.