TDDS are topically administered medicaments in the form of patches that deliver drugs for systemic effects at predetermined and controlled rate.
Transdermal patch is an adhesive patch, that has a coating of medicine (drug), that is placed on the skin to deliver specific dose of the medicine, into the blood over a period of time.
2. CONTENTS:
Introduction
Advantages-Disadvantages
Comparison between IV, Oral and TDDS
Anatomy and Physiology of Skin
Permeation of Drug Molecule through Skin
Percutaneous Absorption
Basic components of TDDS
Factors affecting Transdermal Permeation
Evaluation of TDDS
Application
Marketed Product
Conclusion
References.
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3. INTRODUCTION-
TDDS are topically administered medicaments in the form of
patches that deliver drugs for systemic effects at
predetermined and controlled rate.
Transdermal patch is an adhesive patch, that has a coating
of medicine (drug), that is placed on the skin to deliver
specific dose of the medicine, into the blood over a period of
time.
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4. INTRODUCTION-
TDDS is a one in which:
Drug is delieverd by skin portal to systemic circulation
At a predetermined rate
At maintained clinically effective conceration
Over prolonged period of time
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5. ADVANTAGES:
Avoidance of first-pass effect,
Long duration of action,
Comparable characteristics with IV infusion,
Ease of termination of drug action, if necessary,
No interference with gastric and intestinal fluids,
Suitable for administered of drug having-
* Very short half-life, e.g. nitroglycerine.
* Narrow therapeutic window.
*Poor oral availability.
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6. DISADVANTAGES:
Poor diffusion of large molecules,
Skin irritation,
Requires high drug load,
Unsuitable –If drug dose is large,
Absorption efficiency is vary with different sites of skin
It cannot achieve high drug
level in blood or plasma.
It cannot deliver ionic drugs.
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7. COMPARISON BETWEEN
IV,ORAL AND TDDS:
ADVANTAGES IV ORAL TDD
Avoid hepatic
first-pass effects
YES NO YES
Constant drug
levels
YES NO YES
Self-
administration
NO YES YES
Termination of
therapy
NO YES YES
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9. Skin is the part of Integrated system i.e. it helps to
maintain body temp and protect It from surrounding
environment.
It covers an area of about 2m2 and 4.5-5 kg i.e. about
16% of total body weight in adults.
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11. 1.EPIDERMIS-
Stratum Cornium- consists of 25 to 30 layers of flattened
dead keratinocytes. Which makes it water repellent.
Stratum Granulosm- consists of 3 to 5 layers and under
goes Apoptosis. It contains granules known as Keratohyalin.
These granules release Lipid rich secretion, which acts as
the water repellent.
Stratum Spinosum-
contains 8 to 10 layers of
cells and it is closely
arranged.
Stratum Basal-consists of
single layer of cubical or
columnar keratinocytes.
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12. 2.DERMIS-
Composed of strong connective tissue containing collagen
and elastic fibres, hence it can easily stretch and recoil
easily.
Blood vessel, nerves gland and hair follicles are
embedded in this layer.
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13. 3.SUBCUTANEOUS LAYER-
It is also called as Hypodermis.
It is made up of loose connective tissue, including Adipose
tissue.
This helps to insulate
the body by monitoring
heat gain and heat loss.
The dermis is the layer
of tissue that is Deeper
and Thicker than
epidermis.
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14. PERMEATION OF DRUG
MOLECULE THROUGH
SKIN:
It express by Fick’s first law of Diffusion-Drug molecule
diffuse from a region of higher conc. to one of lower conc.
until equilibrium is attained.
The process of Diffusion of molecule is driven by gradient
between high concentration to low concentration.
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15. Fick’s First law of Diffusion-
dm/dt = J = D A K/h
Where,
dm / dt =J= study state flux
D = diffusion coefficient
A = surface area
K = partial coefficient between the Stratum
corneum and the vehicle
h = diffusional path length or membrane
thickness
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21. Pressure Sensitive Adhesives (PSA)-
A PSA is a material that helps in maintaining an intimate
contact between transdermal system and the skin surface.
Some widely used pressure sensitive adhesives are-
Eg- Polyisobutylenes, Polyacrylates, Silicones.
Backing Laminate:
Hold and protect the drug reservoir from exposure to
atmosphere.
Avoid loss of drug
Accept printing
High flexibility
Eg- vinyl, polyethylene and polyester films, aluminium foil.
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22. Liner-
Protects the patch during storage. The liner is removed prior
to use. Drug – Drug solution in direct contact with release
liner.
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24. Evaluation of TDDS:
1. Evaluation of Adhesive
a. Peel Adhesion Properties- It is the force required to remove
coating from a test substrate.
b. Tack Properties- It is the ability of polymer to adhere to a
substrate with little contact pressure.
Probe tack test
c. Shear Strength Properties- It is the measurement of the
cohesive strength of an adhesive polymer.
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25. APPLICATIONS:
For treatment of Angina Pectoris,
Smoking cessation(Nicotine Patch),
Contraceptive,
Antiemetic,
Anti-inflammatory,
Cosmetics.
Transdermal patch of nicotine, which releases nicotine in
controlled doses to help with cessation of tobacco smoking.
Nitroglycerine patches are also sometimes prescribed for the
treatment of Angina
Clonidine, the antihypertensive drug and ketoprofen, the
non-steroidal anti-inflammatory drug are also available in the
form of transdermal patches
Transdermal delivery agent for the Attention Deficit
Hyperactivity Disorder (ADHD).
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27. CONCLUSION
As we know, the basic functions of the skin is protection and
hence it is difficult to target the skin for drug delivery.
Because skin having numerous layers. But using novel
techniques in TDDS we have successfully penetrate the drug
into systemic circulation.
Transdermal drug delivery system is useful for topical and
local action of the drug. Due to large advantages of the
Transdermal Drug Delivery System and various permeation
enhancers which would significantly increase the number of
drugs suitable for Transdermal drug delivery system, this
system interests a lot of researchers. Transdermal Drug
Delivery System a realistic practical application as the next
generation of drug delivery system.
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28. REFERENCES
Brahmankar D. M., Jaiswal Sunil B.(2009) Biopharmaceutics
and Pharmacotherapeutics-A Treatise, 2nd edition, pp-495-
501.
Jain, N.K. (1997) Controlled and novel drug delivery. 1st ed.
New Delhi: CBS publishers and distributors, pp. 100- 127.
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