TDDS are topically administered medicaments in the form of patches that deliver drugs for systemic effects at predetermined and controlled rate.

1. Presented By;
PRABAKARAN.M
M.Pharm (1-Semester)
Sub: Drug Delivery System
Dept. of Pharmaceutics
Vinayaka Missions College Of Pharmacy
Salem

2. CONTENTS:
1. Introduction
2. Skin
3. Penetration Enhancers
4. Types of TDDS
5. Drug selection criteria
6. Advantages of TDDS
7. Disadvantages of TDDS
8. Basic components of TDDS
9. Evaluation study of TDDS

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.

4. SKIN:
Skinhas mainly 3 layers:
1)Epidermis
a) Stratum Corneum
(Horny Layer)
b) Stratum Lucidum
(Clear layer)
c) Stratum Granulosum
(Granular Layer)
d) Stratum Spinosum
(Spiny layer)
e) Stratum Germinativum
(Regenerative layer)
2)Dermis
3)Subcutaneous layer

5. 1. EPIDERMIS
a) Stratum Corneum- Consists of 25 to 30 layers of
flattened dead keratinocytes. Filled with keratin.
b) Stratum Lucidum- Consists of 3 to 5 transparent,
flattened dead keratinocytes.
c) Stratum Granulosum- Consists of 2 to 5 layers of
flattened keratinocytes.
d) Stratum Spinosum- Contains 8 to 10 layers of cells
and it is closely arranged.

6. d)Stratum Basal- consists of single layer of cubical or
columnar keratinocytes.
2. DERMIS
 Composed of strong connective tissue containing
collagen and elastic fibres, hence it can easily stretch
and easily recoil.
 Blood vessel, nerves gland and hair follicles are
embedded in this layer.

7. 3. SUBCUTANEOUS LAYER
 It is also called as Hypodermis.
 It is made up of loose connective tissue, including
Adipose tissue.
 This helps to protect the internal and external factors
of skin.

8. PERCUTANEOUSABSORPTION

9. PENETRATION ENHANCERS:
 Increases the absorption of penetrant through the skin.
Classification of Penetration enhancers:
Chemical Enhancers;
e.g. Azone, Pyrrolidone, Fatty acids, Essential oils,
terpenes, organic solvents.
Physical Enhancers;
e.g. Ionotophoresis, electroporation, Microneedles.

10.  Surfactants;
Anionic surfactant : Sodium Lauryl Sulphate,
Dioctyl sulphosuccinate.
Non-ionic surfactant: Pluronic F127, Pluronic F68
Bile Salts : Sodium taurocholate, Sodium
deoxycholate.
 Binary systems: Propylene glycol, Oleic acid.
 Sulfoxide: DMSO, DMF, DMA.
 Miscellaneous: Urea, Calcium thioglycholate.

11. Properties for Ideal Penetration Enhancers;
 Non-toxic, non-irritating and non-allergic.
 Rapid working.
No pharmacological activity within the body.
 Work unidirectionally.
 When removed from the skin, barrier properties
should return both rapidly and fully.
 Compatible with both excipients and drugs.
 Cosmetically acceptable.

12. Uses of Penetration Enhancers:
1. To increase the delivery of ionisable drugs.
Example: timolol maleate.
2. To deliver the impermeable drugs. Example: heparin.
3. To maintain level of drug into blood stream.
4. To improve the efficacy of less potent drugs with higher
dose. Example: oxymorphane.
5. To deliver the drugs having high molecular weight like
peptide and hormones
6. To decrease lag time of transdermal drug delivery system

13. Factors Affecting Transdermal Permeation
Partition co-efficient
pH Condition
Drug Concentration
Molecular weight.
TYPES OF TDDS:
1) Single layer Drug in Adhesive
2) Multi layer Drug in Adhesive
3) Drug Reservoir in Adhesive
4) Drug Matrix in Adhesive

14. 1) Single layer Drug in Adhesive
The Single-layer Drug-in-Adhesive system is
characterized by the inclusion of the drug directly
within the skin-contacting adhesive.
In this transdermal system design, the adhesive
not only serves to affix the system to the skin, but also
serves as the formulation foundation, containing the
drug and all the excipients under a single backing film.

15. 2) Multi layer Drug in Adhesive
The Multi layer Drug in Adhesive is similar to the
Single layer Drug-in-Adhesive in that the drug is
incorporated directly into the adhesive.
3) Drug Reservoir in Adhesive
The Reservoir transdermal system design is
characterized by the inclusion of a liquid compartment
containing a drug solution or suspension separated from the
release liner by a semi-permeable membrane and adhesive.

16. 4) Drug Matrix in Adhesive
The Matrix system design is characterized by
the inclusion of a semisolid matrix containing a drug
solution or suspension which is in direct contact with
the release liner.
The component responsible for skin adhesion is
incorporated in an overlay and forms a concentric
configuration around the semisolid matrix.

17. DRUG SELECTION CRITERIA

18. Drug Characters Suitable for TDDS:
Physico-chemical properties of drug
 Should have Molecular weight less than 1000
daltons (800-1000).
 Should have affinity for both lipophilic and
hydrophilic phases.
 Should have low melting point.
Biological properties of drug
Should be potent(less than 20mg).
Half life should be short.

19. Must not induce a cutaneous irritant or allergic
response.
Drugs which degrade in the GI tract or inactivated by
hepatic first pass effect are suitable candidate.
Tolerance to the drug must not develop.
Drugs which has to be administered for a longer
period of time can be formulated.
Drugs which cause adverse effects to non target
tissues can also be formulated.

20. ADVANTAGES OF TDDS:
 Easy to use.
 Avoidance of first-pass effect.
 Long duration of action.
 Comparable characteristics with IV infusion.
 No interference with gastric and intestinal fluids.
 More improved and convenient patient compliance.
 Self medication is possible.
Suitable for administered of drug having-
Very short half-life, e.g. nitroglycerine.
Narrow therapeutic window.
Poor oral availability.

21. DISADVANTAGES OF TDDS:
 Poor diffusion of large molecules.
 Skin irritation.
 Unsuitable –If drug dose is large.
 Absorption efficiency is vary with different sites of
skin.
 Daily dose more than 10mg is not possible.

22. Basic Components of TDDS:
1. Polymer matrix
Natural polymers
 Cellulose derivatives, Gelatin, Shellac, Waxes, Proteins
Gums, Natural rubbers, starch.
Synthetic polymers
 PVA, PVC, Poly amide, Poly acrylate, Polyurea, PVP,
Epoxy, etc.
2. The drug
3. Permeation enhancers
4. Other excipients

23. EVALUATION OF TDDS

24. Physicochemical evaluation of TDDS:

25. In-vitro evaluation of TDDS:

26. In-vivo evaluation of TDDS:

27. Stability study of TDDS:
According to the International Conference on
Harmonization (ICH) guidelines by storing the TDDS
samples at 40± 2°C and 75 ± 5% RH for 6 months. The
samples were withdrawn at 0, 30, 60, 90 and 180 days
and analyzed for drug content by suitable analytical
technique.