An Overview of Transdermal Drug Delivery System (TDDS)

1. Welcome to my presentation

2. Presentation Topic:
An Overview of Transdermal Drug
Delivery System (TDDS)
Presented by
Md. Nur-A-Rahman
Reg No: 17207010
Department of Pharmacy
University of Asia Pacific

3. Contents :
 Definition
 Ideal Characteristics
 Advantages
 Disadvantages
 Uses
 Anatomy of Skin
 Mechanism of Transdermal drug
 Factors Affecting of TDDS

4. Contents……
 Types
 Basic Components of TDDS
 Recent Development of TDDS
 Evaluation Parameters
 Recent Enhancing Techniques for TDDS
 Conclusion

5. Introduction
Definition:
Transdermal drug delivery system (TDDS) are systems
that utilize skin as a site for continuous drug administration
into the systemic circulation.
Example:
Scopolamine which is controlled release Transdermal drug that
is used in motion sickness

6. Ideal Characteristics of TDDS
The ideal characteristics of Transdermal drug delivery are as
follows:
 The pH of the solution should be between 5-9.
 Drugs with low melting point (less than 200°C) should use.
 Patch size should be less than 40 cm2.
 Shelf life up to 2 years.

7. Advantages of TDDS
 Topical patch are painless.
 Self-administration is possible.
 Patches are cost effective.
 Duration of action gets extended & predictable.

8. Disadvantages of TDDS
 It requires high blood concentration.
 It may be uneconomic.
 Transdermal drug delivery system is restricted to
potent drug.
 Uncomfortable to wear.

9. Uses
 Nitroglycerin patches are used for the treatment of
angina in lieu of sublingual pills.
 The first commercially available vapor patch of
nicotine to reduce smoking was approved in Europe in
2007.

10. Anatomy of Skin
1. Epidermis
a) Stratum corneum
b) Stratum lucidum
c) Stratum granulosum
d) Stratum spinosum
2. Dermis
3. Hypodermis

11. Mechanism of Transdermal Permeation
Transdermal permeation of a drug moiety involves the following steps-
 Sorption by stratum corneum
 Permeation of drug through viable epidermis
 Uptake of the drug moiety by the capillary network in the dermal papillary layer.
 The rate of permeation of drug moiety across the skin is governed by following equation:
dQ/dt= Ps(Cd-Cr)
Where,
 dQ/dt – Rate of permeation
 Ps – Permeability coefficient
 Cd – Concentration in donor compartment
 Cr – Concentration in receptor compartment

12. Factors Affecting of TDDS
Factors affecting can be divided in two classes as-
 Biological factors
a) Condition of Skin
b) Skin Age
c) Blood Supply
d) Skin Metabolism
 Physicochemical factors
a) Skin Hydration
b) Temperature and pH
c) Drug Concentration
d) Molecular Size and Shape

13. Types of TDDS
There are four main 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

15. Basic Components of TDDS
1) Polymer matrix
2) Drug
3) Permeation enhancers.
4) Pressure sensitive adhesives (PSAs)
5) Backing membrane
6) Release liner
7) Other excipients

16. Recent Development of TDDS
Several technologies have been successfully developed to
provide a rate control over the release and the transdermal
permeation of drugs. These technologies can be classified into
four approaches as follows-
1. Membrane permeation – controlled systems
2. Adhesive dispersion – type systems.
3. Matrix diffusion – controlled systems.
4. Micro reservoir type systems.

17. Evaluation Parameters of TDDS
The evaluation methods for ransdermal dosage form can be classified into
following type-
1. Physicochemical evaluation
a)Thickness b)weight Uniformity
2. In vitro evaluation
a) Flow-Through Diffusion Cell b)The Paddle over Disc
3. In vivo evaluation
a)Animal models b)Human models
4. Stability studies

18. Recent Techniques for Enhancing TDDS
1. Structure-Based Enhancement Techniques
2. Electrically-Based Enhancement Techniques
3. Velocity Based Enhancement Techniques
4. Other Enhancement Techniques

19. Conclusion:
 Transdermal drug delivery technologies are becoming
one of the fastest growing sectors within the
pharmaceutical industry.
 Despite some disadvantages, transdermal drug delivery
offers many advantages capable of improving patient
health and quality of life