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Title: HEALTH & MEDICINE - DRUG DELIVERY * Image courtesy of


1
HEALTH MEDICINE - DRUG DELIVERY
2
MODULE OUTCOMES
  • Have an understanding of vaccination
  • Investigate the structure and functions of skin,
    and how vaccines/drugs are delivered through it
  • Understand why transdermal patches offer
    advantages over current immunisation practises
  • Identify recent developments in nanotechnology
    and how they impact on vaccination strategy and
    other health outcomes.

3
WHAT IF?
  • WHAT IF YOU NEVER HAD TO HAVE ANOTHER NEEDLE?

4
WHAT IF?
  • WHAT IF YOU COULD PREVENT DISEASE MORE EASILY IN
    DEVELOPING COUNTRIES?

5
DID YOU KNOW?
  • A young person with Type 1 diabetes will use up
    to 1500 syringes a year - Associate Professor
    John Fitzgerald, School of Population Health,
    University of Melbourne, July 2007
  • Globally, around 30 billion syringes are used per
    year 800 million are used by Australians.

6
WHAT IF?
  • What if there was an alternative to needles for
    delivery of vaccines and drugs like insulin?

7
WHAT IS A TRANSDERMAL PATCH?
Delivery of drug/vaccine into skin
Example of transdermal patch
  • DefinitionAn adhesive patch containing micro
    sized needles that painlessly penetrate the skin
    to deliver nano-formulated drugs and vaccines.
  • (This example developed by Nanotechnology
    Victoria)

8
ACTIVITY 1
Complete the Vaccination SWOT Analysis Activity
to compare the strengths and weaknesses of
conventional and transdermal methods of
vaccination.
9
HOW DO VACCINES WORK?
  • Vaccines deliver antigens to the skin or blood
    stream antigens are fragments of infectious
    agents
  • The antigen is gobbled up by an antigen
    presenting cell (APC)
  • The APC travels to a lymph node where it
    interacts with lymphocytes (a type of immune
    cell).

10
HOW DO VACCINES WORK?
  • In the lymph node, specific lymphocytes targeted
    at the antigen in the vaccine are produced-
    these cells persist in the body as memory cells
  • Then if an actual infectionoccurs, the memory
    cells are primed and ready to act and combat the
    infectione.g. produce antibodies specific to the
    antigen.

11
ANIMATION
Watch the Vaccination and Transdermal Patch
Animations to improve your understanding of
delivering vaccines and drugs via the skin.
12
BENEFITS OF TRANSDERMAL PATCHES
What are the benefits of transdermal delivery
from a medical point of view?
13
BENEFITS OF TRANSDERMAL PATCHES
  • Protrusions can be specifically engineered to
    ensure
  • Delivery directly to immune cells therefore less
    material required
  • Painless application and no scar tissue formation
  • Versatility in applications vaccines, drugs,
    hormones, wound healing proteins.

Microscopic images of transdermal patch
protrusions
14
BENEFITS OF TRANSDERMAL PATCHES
  • Transdermal patches can deliver nano-formulated
    drugs/vaccines, which- have unique properties-
    can easily enter blood vessels once delivered to
    skin- can target particular cell types, such as
    immune cells
  • Examples of drugs that could be patch-delivered
    - proteins such as insulin
  • Examples of vaccines that could be patch
    delivered- protein vaccines- DNA vaccines.

15
BENEFITS OF TRANSDERMAL PATCHES
  • Due to directed delivery of nano-formulated
    drugs/vaccines, the use of patches means that-
    only small quantities of drugs/vaccines are
    required- less drug/vaccine is wasted i.e.
    dispersed in blood or connective tissue before it
    reaches target cells- less side effects due to
    small dosage delivered directly to target cells
    - an optimal immune response is generated.

16
NANO-FORMULATED VACCINES TRIGGER AN OPTIMAL
IMMUNE RESPONSE
Data was generated by vaccinating mice with
various sized particles, and then counting the
number of activated immune cells.
17
ADVANTAGES OF TRANSDERMAL PATCHES SUMMARY
  • Delivery of nano-sized particles directly to the
    immune system
  • Delivery of molecules that normally cannot
    penetrate the skin
  • Lower dosages less side effects
  • Easy to use, no needle-stick injury, low risk of
    infection, pain-free
  • Can be self-administered, or given by a
    non-medical person
  • Smaller, lighter, lower transport cost
  • Mass production cost benefits
  • Suitable for public health programse.g. air-drop
    into disaster zones
  • Suitable for veterinary purposes
  • Biocompatible and biodegradable material used to
    make patches
  • Can achieve short- long-term delivery.

18
OTHER EXAMPLES OF TRANSDERMAL PATCHES
  • In addition to Nanotechnology Victoria, other
    groups within Australia are working on
    transdermal patches eg Dr Mark Kendall at AIBN,
    Queensland- developing a micro-nano projection
    array patch (Nanopatch)- could be used for
    vaccination or DNA delivery- vaccine/DNA
    molecules are dry-coated on to the patch
    projections for delivery to target cells through
    the top layer of skin (epidermis)
  • Nicotine patches (to help smokers quit)- plastic
    chamber within patch containsnicotine- a
    selectively permeable membrane allows diffusion
    of nicotine into the skin.

19
WEARABLE TRANSDERMAL PATCHES
  • Transdermal patches could be incorporated into
    jewellery
  • This would be particularly beneficial for the
    transdermal delivery of drugs such as insulin.

Insulin-dispensing rings designed by
Nanotechnology Victoria Artist in Residence Ms
Leah Heiss
20
ACTIVITY 2
Perform the Transdermal Patches Activity to gain
an understanding of the history and development
of transdermal patches.
21
EXPERIMENT 1 TRANSDERMAL IMMUNISATION
Perform the Modelling Transdermal Immunisation
Experiment to better visualise this mode of
delivering vaccines and drugs.
22
DESIGNING BETTER TRANSDERMAL PATCHES
  • To design better patches and drugs/antigens,
    scientists need to understand skin
  • For example, certain drugs can penetrate
    particular layers of the skin more effectively
    than others
  • Lets examine the structure and function of
    human skin.

23
HUMAN SKIN
THE SKIN IS THE LARGEST AND HEAVIEST ORGAN OF THE
BODY.
  • Functions of skin
  • A barrier against pathogens
  • A water proof coat
  • Contains melanin a pigment that helps protect
    against UV radiation
  • Protects internal organs.

24
WHAT IS SKIN MADE OF?
  • Epidermis the outer most layer
  • Dermis holds the hair, muscles, blood supply,
    sebaceous glands, nerve receptors and fat.

25
ACTIVITY 3 EXPERIMENT 2
Perform the Structure and Function of Skin
Activity and/or the Skin Observation Experiment
to learn more about skin.
26
FUNCTION OF SKIN BARRIER
  • Skin cells are being replaced 24/7
  • New cells are made in the lower epidermis by cell
    division
  • New cells move towards the surface to replace old
    cells
  • Old cells die and flake off
  • In the epidermis the cells become flatter and
    keratinized making them tough and water proof.

27
FUNCTION OF SKIN TEMPERATURE CONTROL
  • Human body temperature is 37C
  • The skin is critical in temperature control
  • Humans have adaptations to help control
    temperature
  • Sweating
  • Capillaries changing size
  • Gooses bumps
  • Shivering.

28
TEMPERATURE CONTROL SWEATING
  • The skins temperature receptors sense the
    external temperature change and send a signal to
    the brain
  • Brain sends a message for the skin to produce
    sweat
  • Energy (heat) needed to change liquid water to
    gas
  • Sweat evaporates and cools the body down.

energy absorbed
SOLID
LIQUID
GAS
energy released
29
TEMPERATURE CONTROL VASODILATION
  • Blood in the skin has a network of small
    capillaries
  • When you are cold, the muscles around capillaries
    constrict, capillaries become narrow, less blood
    passes to the surface and less heat is lost
  • When hot, the muscles around capillaries relax,
    more blood passes to the surface and more heat
    passes to the skin surface.

30
TEMPERATURE CONTROL GOOSE BUMPS
  • When you are cold the muscles around the hairs in
    the skin contract and the hairs become erect
  • Hairs trap a layer of warm air
  • Reduces heat loss.

warm
cold
31
EXTENDED LEARNING
OTHER EXAMPLES OF NANOTECHNOLOGY IN MEDICINE.
  • HIV/AIDS Dendrimers
  • Teeth Recaldent.

32
WHAT IF?
What if you could stop the spread of HIV in the
developing world?
Photo taken outside a school in Zambia, Africa in
2005
33
HIV PREVENTION VIVA GELTM
  • Viva Gel contains active ingredients called
    dendrimers
  • Viva Gel is used at the skin surface to prevent
    viral infection
  • Dendrimers are branched, nanosized molecules with
    specific known properties and are tailor made for
    a specific purpose.

34
HIV INFECTION
  • The HIV virus (yellow and purple) infects human
    T-cells (pink) by attaching to receptors on the
    surface of the T-cell (an important immune cell)
  • The virus then enters the T cell and reproduces
    inside it
  • The virus kills the T cells causing the person to
    lose immunity.

35
HOW THE DENDRIMER WORKS
  • The dendrimer binds to proteins on the surface of
    the HIV virus.
  • The virus cant attach to the receptors on the
    human T cells.
  • Infection is prevented.

36
TOOTH REPAIR RECALDENT
  • A nano-modified milk protein that delivers
    Calcium and Phosphate to teeth to reform the
    tooth enamel.

Recaldent was developed in Australia
Watch video www.gcamerica.com
37
SUMMARY
  • Transdermal patches incorporating nanotechnology
    can be utilised for vaccine and drug delivery via
    the skin
  • Nanotechnology Victoria is developing transdermal
    patches for drug delivery
  • Designing and understanding how vaccines work
    requires an appreciation of the structure and
    function of skin.

38
REVISION
  • Why are scientists interested in transdermal drug
    delivery?
  • How does vaccination work?
  • Apart from vaccines, what other substance could
    be delivered through the skin?
  • Describe the functions of human skin.

39
HEALTH MEDICINE - DRUG DELIVERY
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