This document discusses approaches used in the development of transdermal drug delivery systems. It describes four main approaches: 1) membrane permeation-controlled systems, 2) adhesive dispersion-type systems, 3) matrix diffusion-controlled systems, and 4) microreservoir or microsealed dissolution systems. It also discusses the basic components of transdermal drug delivery systems, which include polymer matrices, drugs, permeation enhancers, and other excipients.

1. Approaches Uses in
Devolopment of Transdermal
Drug Delivery Systems
PRESENTED BY :
DIPAYAN DAS
B.PHARM 6TH SEM
DEPT. OF PHARMACEUTICS
NETAJI SUBHAS CHANDRA BOSE INSTITUTE OF PHARMACY

2. Definition :
 Transdermal therapeutic systems are defined as self-contained, discrete
dosage forms which, when applied to the intact skin, at a controlled rate to
the systemic circulation.
OR
 Transdermal drug delivery systems (TDDS) are system that utilize skin as a
site for continuous drug administration into the systemic circulation.

3. Advantages :
 Transdermal delivery can increase the therapeutic value of many drugs by avoiding
specification due to hepatic ‘First-pass’ effects, formation of metabolites that cause
side effects, short half-life frequent dosing.
 Self-administration is possible with this system.
 The drug input can be terminated at any point of time by removing transdermal
patch.
 Allows effective use of drugs with short biological half-life.
 Allow administration of drugs with narrow therapeutic window.
 Provides controlled plasma level of very potent drugs.
 Drug input can be promptly interrupted when toxicity occurs.

4. Disadvantages :
 The barrier function of the skin changes from one side to another on the
same person, from person to person and with age.
 Drug that require high blood levels can’t be administrated adhesive may
not adhere well to all types of skin.
 Drug or drug formulation may cause skin irritation or sensitization.
 Uncomfortable to wear.
 May not be economical.

5. BASIC COMPONENTS OF TRANSDERMAL DRUG
DELIVERY SYSTEMS :
The components of transdermal devices include :
I. Polymer matrix or matrices –
1. Natural Polymers, 2. Synthetic Elastomers, 3. Synthetic Polymers
II. The drug –
1. Physiochemical properties, 2. Biological properties
III. Permeation enhancers –
1. Solvents, 2. Surfactants, 3. Binary Systems, 4. Miscellaneous chemicals
IV. Other excipients –
1. Adhesive, 2. Backing Membrane

6. APPROACHES USED IN DEVOLOPMENT OF
TRANSDERMAL DRUG DELIVERY SYSTEMS :
 1. Membrane permeation – controlled
systems : Drug reservoir is encapsulated in a shallow
compartment moulded from a drug-impermeable
metallic plastic laminate and a rate controlling
polymeric membrane which may be micro porous or
non-porous. The drug molecules are permitted to
release only through the rate – controlling polymeric
membrane. Examples of this system are Transderm-
nitro, Transderm-scop etc.

7. APPROACHES USED IN DEVOLOPMENT OF
TRANSDERMAL DRUG DELIVERY SYSTEMS :
 2. Adhesive Dispersion – Type Systems: The
drug reservoir is formulated by directly dispersing
the drug in an adhesive polymer and then
spreading the medicated adhesive, by solvent
casting, on to a flat sheet of drug impermeable
metallic plastic backing to form a thin drug
reservoir layer. On the top of the drug reservoir
layer, thin layers of non-medicated, rate-
controlling adhesive polymer and constant
thickness are produce an adhesive diffusion –
controlled delivery system.

8. APPROACHES USED IN DEVOLOPMENT OF
TRANSDERMAL DRUG DELIVERY SYSTEMS :
 3. Matrix Diffusion - Controlled Systems: The
drug reservoir is formed by homogenously
dispersing the drug solids in a hydrophilic or
lipophilic polymer matrix. The medicated polymer
is then molded into a medicated disc with a
defined surface area and controlled thickness.
Drug reservoir containing polymer disc is then
pasted onto an Occlusive base plate in a
compartment fabricated from a drug-
impermeable plastic backing membrane. e.g.
Nitro-Door.

9. APPROACHES USED IN DEVOLOPMENT OF
TRANSDERMAL DRUG DELIVERY SYSTEMS :
 4. Micro reservoir type or Micro
sealed Dissolution - The micro reservoir
type drug delivery system can be
considered a combination of the reservoir
and matrix diffusion type drug delivery
systems. This transfer is then produced by
positioning the medicated disc at the
centre and surrounding it with an adhesive
rim. E.g. nitroglycerine.

10. The Future
 The future development of transdermal therapeutic system is
multifaceted. Improvement in the presently available devices
to provide optimum blood levels, availability of better skin
permeability enhancers and extensive use of redesigned drug
molecules (prodrugs) and novel formulation approaches
include liposomes, niosomes and microemulsions are some of
the aspects envisioned. The market for transdermal devices
has been estimated to increase in future and has recently
experienced annual growth of at rate of 25%. This figure will
rise in future as novel devices emerge and list of marketed
transdermal drug increases. Transdermal delivery of
analgesicsis likely to continue to increase in popularity as
there are further improvements in design.

11. References :
 N.K.Jain, Controlled & Novel Drug Delivery, CBS Publisers & Distributers, New Delhi,
5th edition, Page 100-121, 2007.
 Y.W.Chien, Novel Drug Delivery Systems, Infoma Medicals, Vol. 50, New York, Page
211-229, 1991
 www.wikipedia.org/wiki/Transdermal patch
 www.Google.com/Transdermal Drug Delivery Systems