Introduction: A Transdermal patch (TD patch) is a
medicated adhesive patch that is placed on the skin to
deliver a time released dose of drug through the skin
and into the systemic circulation. The most common
transdermal patch, popularly called the nicotine patch,
contains nicotine and is used to quit the habit of
tobacco smoking (smoking deterrent) and is the first TD
patch on the Indian market. Transdermal patches have
been available on the global market for more than 25
years as a successful alternative to systemic drug
delivery for selected drug molecules, and are know as
Transdermal Drug Delivery Systems (TDDS). They are also
known as Transdermal Therapeutic Systems, abbreviated as
TTS. The drug delivery mechanism is the passive
diffusion of drug across the skin from this adhesive
transdermal patch. Despite the relatively higher costs,
the transdermal patches have proved advantageous for
delivery of selected drugs, such as estradiol, ethinyl
estradiol, clonidine, fentanyl, lidocaine, nicotine,
nitroglycerin, norethindrone acetate, norelgestromin,
oxybutynin, prilocaine, scopolamine, and testosterone.
Since the first transdermal patch, scopolamine was
approved in 1979 all the drug molecules mentioned above
are available as approved transdermal products in
American and European market. In India TD patches
containing active drug molecule such as nicotine,
estradiol, fentanyl, glyceryl trinitrate, and
testosterone are available. Transdermal patches are
utilized for mainly hormonal therapy, narcotic
analgesia, antihypertensive & anti-emetic therapies, and
smoking deterrent. Transdermal patches offer superior
uniformity of drug concentrations in plasma throughout
their duration of use. This results in reduced side
effects and, sometimes, improved efficacy over other
dosage forms.
The principal advantages of the transdermal patches
include avoidance of biochemical degradation of the drug
molecule in the gastrointestinal tract, variable
gastrointestinal absorption and metabolism in liver, and
reduced frequency of drug dosage for short acting drugs.
The drug needs only once in 2/3 days or even a week from
patch instead of several times a day. The major
limitation of TDDS is the low skin permeability of most
of the drugs. That is, the skin barrier limits the
number of drugs that can be delivered by passive
diffusion from the TD patch.
|
The above content is an
abstract only. For the full Article please contact:
KONGPOSH Publications Pvt. Ltd.
ICS House, C-19, Commercial Complex, SDA, Opp. IIT Gate,
New Delhi, India -110016
Tel.: 26855839, 20057149, Fax: 91-11-26855876
Email:
info@kppub.com /
fpc@vsnl.com, Website:
http://www.kppub.com |
