1. TRANSDERMAL DRUG DELIVERY SYSTEM
(TDDS)
Presented By;
Mr. Trilok D. Shahare
M.Pharm, I Semester
Department of Pharmaceutics
D. B. C. O. P. Besa, Nagpur
Guided By;
Dr. N. M. Mahajan
Department of pharmaceutics
D. B. C. O. P. Besa, Nagpur
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2. CONTENTS
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1 Introduction
2 Advantages
3 Disadvantages
4 Skin And Structure Of Skin
5 Function Of Skin
6 Factor Affecting TDDS
7 Type/Technology For Development Of TDDS
8 Evaluation Parameters
9 Reference
3. INTRODUCTION
- Transdermal drug delivery system (TDDS), also known as
patches.
- Transdermal is a rout of administration wherein active
ingredient are delivered across the skin for systemic
distribution.
- It is a dosage forms designed to deliver a therapeutically
effective amount of drug across a patient’s skin.
- Transdermal system, was approved by FDA in 1979 for the
prevention of nausea and vomiting.
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5. General Patches….
Backing – protect the patch from environment.
Membrane – Control the release of drug.
Adhesive – Adher the component of patch together adhere the patch release.
Liner- Protect the patch during storage
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6. TDDS offers…
Iv Oral TDDS
Reduced first-pass
effect.
Yes No Yes
Constant drug level Yes No* Yes
Self-administration No Yes Yes
Unrestricted patient
activity
No Yes Yes
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7. Advantages :
Easy to use.
Self medication is possible.
Avoidance of first pass metabolism, Salivary
metabolism and intestinal metabolism.
Avoidance of gastrointestinal incompatibility.
No interaction with food or drink, and enzyme.
Prolong duration of action (ranging from few hrs. to one
week)
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8. Disadvantages :
Local irritation at site of application.
Allergic reaction.
Difficult in long time adherence.
Cannot deliver ionic drug.
The adhesive used may not adhere well to all type of
skin.
Difficult to administer large dose.
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9. About Skin :
Skin is the largest organ in the body.
Primary site of delivery.
It consist of 6% of total body weight (e.g 50kg person-3kg of
skin).
Skin pH acidic 4.2-5.6 pH.
The skin contains a protein called keratin which is also in
found in hair and nails.
Each 5 square cm of skin may have up to 600 sweat gland.
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10. Structure of skin :
• I. Epidermis
Stratum corneum (Horny cell layer)
Stratum granulosum ( Granular Layer)
Stratum spinosum (Prickly layer)
Stratum basale
• II. Dermis
• III. Hypodermis or Subcutaneous layer
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11. I. Epidermis :
Outer most layer
Composed of stratified squamous
epithelial cell.
Epidermis layer provides a
barrier to infection from
environmental pathogen.
And regulate amount of water
release from the body.
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12. a) Stratum corneum :
This is the outermost layer of skin called as horny layer with
approximately 10 mm thickness.
Which comprises of 15–30 sheet of non-viable, but
biochemically active corneocytes.
b) Stratum granulosum : is the middle layer of epidermis and
chiefly involved in providing waterproof function. It also
contributes keratinization process of the skin.
c) Stratum spinosum : composed of 8–10 sheet of keratinocytes
with limited dividing capacity.
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13. c) Stratum spinosum : composed of 8–10 sheet of keratinocytes
with limited dividing capacity and is also a seat for langerhan’s cell
d) Stratum basal : is a hub for maturing/aging keratinocytes,
melanocytes, Merkel cells referred as a receptor cells.
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14. II. Dermis
Dermis is a layer of skin between the epidermis and subcutaneous tissues.
It’s major role to provide the much needed responsible for the tensile
strength of skin.
It is a 3 to 5 mm thick layer, composed of matrix connective tissue which
contains blood vessels, lymph vessels and nerves.
In which mechanoreceptors that provides the sense of touch and heat.
Primarily regulates temp. and also provide nutrients and oxygen to the skin.
Major components include :
I. Hair follicles
II. Connective tissue
III. Sweat gland
IV. Blood vessels 14
15. III) Subcutaneous layer :
Subcutaneous tissue, which also known as the hypodermis,
hypoderm is the inner most layer of skin.
It’s is made up of fat and connective tissues that house larger
blood vessels and nerves.
Subcutaneous tissue act as an insulator and regulate body
temperature.
The subcutaneous tissue layer its function to protect the muscle
and bones.
For transdermal drug delivery drug has to penetrate through all
these three layers and reach into systemic circulation.
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16. Function of Skin :
Protection
Sensation e.g. heat, cold, touch, pressure, vibration, tissue injury.
Regulation of body temperature
Formation of vitamin D – by the action of UV on certain parts of skin.
Absorption
Excretion – sweat.
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17. Fig . Diagram showing absorption of molecules through skin layers
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19. MECHANISM OF ABSORPTION
(through skin)
Mechanism involved is passive diffusion.
This can be expressed by FICK’s steady state diffusion,
J = KD/h (co – ci )
Where,
• J = flux per unit area,
• K = stratum corneum –formulation partition coefficient of
drug,
• D = diffusion coefficient in the stratum corneum of path length ‘h’; Co
= Conc. of drug applied to skin & ci = conc. inside the skin.
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25. 1. Polymers Membrane Partition-Controlled TDDS
In this type of systems, the drug reservoir is sandwiched between a drug
impermeable metallic-plastic lamination and rate controlling polymeric
membrane.
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26. Drug mixed with
polymeric solution
Containing unleachable
viscous fluid
That forms
paste like
suspension
Upper coat- drug impermeable metallic-plastic lamination
Middle coat- rate controlling membrane
Lower coat- thin adhesive polymer layer
Molding as TDD System
Packaging machinery
Primary packaging
Secondary packaging
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27. The intrinsic drug release from this type of TDDS is defined by :
𝑑𝑄
𝑑𝑡
=
𝐾𝑚/𝑟
𝐾𝑚/𝑟
𝐾𝑎/𝑚𝐷𝑎𝐷𝑚
𝐷𝑚ℎ𝑎+𝐾𝑎/𝑚𝐷𝑎ℎ𝑚
𝐶𝑟
Where,
Cr – Drug conc. in reservoir compartment.
Km/r & Ka/m – partition coefficient for the interfacial partitioning of drug
from reservoir to membrane & membrane to adhesive respectively.
Da & Dm – Diffusion coefficient in rate control membrane & adhesive
layer.
ha & hm – Thickness of rate controlled membrane and adhesive layer.
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31. The rate of drug release from this type of TDDS is defined.
Where,
Ld – Drug loading dose initially dispersed in polymer matrix
Cp – Solubility of drug in polymer matrix
Dp – Diffusivity of drug in polymer matrix
example :
Nitro-dur II system for angina pectoris
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32. 3. Drug Reservoir Gradient-Controlled TDDS
Drug-impermeable laminate
Drug
Reservoir
Gradient
Adhesive layer
Drug molecules
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33. Drug release from this type can be expressed by-
𝑑𝑄
𝑑𝑡
=
𝐾𝑎/𝑟𝐷𝑎
ℎ𝑎(𝑡)
𝐿𝑑 (ℎ𝑎)
Where,
Ka/r – Partition coefficient for interfacial partitioning of drug from the
reservoir layer to adhesive layer.
Example :
Verapamil for Hypertension
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34. 4. Microreservoir Dissolution-Controlled TDDS
This is combination of reservoir and matrix diffusion type of DDS.
Microreservoir dissolution controlled patch is ready
This medication disc positioned at the centered and surrounded by an
adhesive rim
Drug suspension dispersed into lipophilic polymer to form unleachable
microspheres of drug reservoir
Solid drug suspended in aq. Solution of water soluble polymer
Drug suspension
By polymeric cross linkingUnstable dispersion converted to stable
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36. • The rate of drug release from this system is defined by :
where,
Kl – liquid compartment to polymer matrix
Km – polymer matrix to polymer compartment
Kp – polymer coating membrane
Dl – liquid compartment
Dp – polymer coating membrane
Ds – elution solution
Sl – liquid compartment
Sp – polymer matrix 36
37. hl – liquid layer surround drug particles.
hp – polymer membrane coating around polymer matrix
hd – hydrodynamic diffusion layer surrounding the polymer coating
membrane.
Examples :
Nitro-disc for angina pectoris.
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38. EVALUATION OF TDDS
1) Interaction Studies
2) Thickness of the Patch
3) Weight Uniformity
4) Folding Endurance
5) % Moisture Content
6) % Moisture Uptake
7) Drug Content
8) Polariscope Examination
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40. REFERENCE :
Novel drug delivery systems, 2nd edition, by Y.W. Chien
page no : 301 – 375.
Tanwar, Transdermal drug delivery system : A review,
International Science and Research 2016, 7(6) : 2274-
2290.
Novel drug delivery system, Nirali Prakashan, by Dr.
Dheeraj T. Baviskar, page no : 6.1 to 6.36
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