Transdermal Drug Delivery system

1. Submitted To- Dr. Rameshwar Das
Associate Professor
Submitted By- Muskan
M-506
M.Pharm.
1st Semester

2.  Introduction
 Advantages and Limitations
 Structure of Skin
 Components of Transdermal Patch
 Penetration Enhancers
 Classification of TDDS

3.  Transdermal drug delivery is defined as a self contained
discrete dosage form, which when applied to the intact skin,
will deliver the drug at a controlled rate to the systemic
circulation

4.  Avoidance of first-pass metabolism
 Long duration of action
 Ease of termination of drug action
 Reduces frequency of dosing
 No interference with gastric and intestinal fluids
 Suitable for administered of drug having-
a. Very short half-life, e.g. nitroglycerine.
b. Narrow therapeutic window.
c. Poor oral availability

5.  Heat, cold, sweating and showering prevent the patch from
sticking to the surface of the skin for more than one day. A
new patch has to be applied daily.
 Skin irritation and allergic response
 Restricted to Potent drugs.
 Cannot be used for Large molecules(>500 D)
 Limited Skin Permeability

7. Epidermis It consists of 5 layers-Stratum
corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum germinativum
Dermis Drug is absorbed in this layer
It consists of-
Sweat duct
Hair follicle
Sebaceous gland
Subcutaneous It consists of fat containing areolar
tissue

8. Macro Routes
1. Sweat Duct
2. Through stratum corneum
3. Hair Follicles
Micro Routes
1. Intercellular
2. Transcellular

10. Backing MEmbrane It act as a protivar layer and avoids back
diffusion of drug . It is made up of either
of these-
Polypropylene
Polyethylene
Polyester
Drug Permeable Membrane It act as a rate controlling membrane
It is made up of either of these-
Ethylene vinyl acetate
Microporous polyethylene
Adhesives It enables the patch to adhere to the surface
of skin (stick). It is classified as follows –
Rubber based pressure sensitive adhesives
Acrylic based pressure sensitive adhesive
Release liners It consists of anti-adherent coating
Silicones
Fluoro polymers

11. Suitable Drug Candidate
Physico chemical properties of
drug-
 Should have MW less than 1000
daltons(800-1000)
 Should have affinity for both
lipophilic and hydrophilic phases
 Should have low melting pont
Biological properties of drug-
 Should be potent(less than 20mg)
 Half life should be short
 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

12.  To enhance stratum corneum permeability
Solvents water,ethanol, methanol,DMS, homologs
of methyl sulphoxide, dimethyl
acetamide
Surfactants Anionic surfactants-
Dioctyl sulpho succinate, SLS
Non ionic surfactants-
Pluronic F127, Pluronic F68,etc.
Bile salts-
Sodium taurocholate, sodium deoxy
cholate, sodium tauroglycocholate.
Miscellaneous Urea-hydrating and keratolytic agent,N,N-
dimethyl-m-toluamide, calcium
thioglycolate
Potential Permeation Enhancers Euclyptol,di-o-methyl-B-cyclodextrin and
soyabean casein

13.  Polymer membrane permeation-controlled.
 Polymer matrix diffusion- controlled
 Adhesive diffusion/ dispersion controlled
 Micro reservoir dissolution-controlled

14. 1) Membrane Permeation controlled
( Reservoir Type)
2)Matrix Diffusion Controlled
3) Adhesive diffusion/ dispersion
controlled
4)Micro reservoir dissolution
controlled