A1,
A2,
B,
C1,
C2,
D,
E,
F,
G-H,
I-K,
L,
M,
N,
O,
P1,
P2,
Q-R,
S,
T,
U-V,
W-Z
Catapres-TTS Online, Description, Chemistry, Ingredients - Clonidine Patch
Catapres-TTS Online, Description, Chemistry, Ingredients - Clonidine Patch
DESCRIPTION
Transdermal Therapeutic System
Programmed delivery in vivo of 0.1, 0.2, or 0.3 mg
clonidine per day, for one week.
Catapres-TTS (clonidine) is a transdermal system
providing continuous systemic delivery of clonidine for 7 days at
an approximately constant rate. Clonidine is a centrally acting
alpha agonist
and is an antihypertensive agent. It is an imidazoline derivative
whose chemical name
is 2,6-dichloro-N-2-imidazolidinylidenebenzenamine.
System Structure and Components: Catapres-TTS is
a multilayered film, 0.2 mm
thick, containing clonidine as the active agent. System area is
3.5, 7.0, or 10.5 cm2 and the amount of drug
released is directly proportional to area. (See Release Rate
Concept). The composition per
unit area
of all three dosages is identical.
Proceeding from the visible
surface towards the
surface attached to
the skin, are four layers 1) a backing layer
of pigmented polyester
film; 2) a drug reservoir
of clonidine, mineral
oil, polyisobutylene, and colloidal silicon dioxide; 3) a microporous
polypropylene membrane
that controls the rate
of delivery of clonidine from the system
to the skin surface; 4)
an adhesive formulation
of clonidine, mineral
oil, polyisobutylene, and colloidal silicon
dioxide. Prior to use, a protective
peel strip of polyester
that covers layer 4 is
removed.
Cross Section of the System - Backing; Drug Reservoir; Control
Membrane; Adhesive; Protective Peel Strip
Release Rate Concept: Clonidine film
is programmed to release clonidine at an approximately constant
rate for 7 days. The energy
source for drug release
derives from the concentration
gradient existing between
a saturated solution
of drug in the system
and the much lower concentration prevailing in the skin. Clonidine
flows in the direction of the lower concentration at a constant
rate, limited by the rate-controlling membrane, so long as a saturated
solution is maintained
in the drug reservoir.
Following system application
to intact skin, clonidine in the adhesive layer saturates the skin
sites below the system. Clonidine from the drug reservoir then begins
to wflow through the rate-controlling
membrane and the adhesive
layer of the system
into the systemic circulation
via the capillaries beneath
the skin. Therapeutic plasma
clonidine levels are achieved 2 to 3 days after initial
application of clonidine film.
The 3.5, 7.0, and 10.5 cm2 systems respectively deliver
0.1, 0.2, and 0.3 mg clonidine per
day. To ensure constant release
of drug over 7 days, the total
drug content of the system
is greater than the total amount of drug
delivered. Application of a new system
to a fresh skin site at weekly
intervals continuously maintains therapeutic
plasma concentrations of clonidine.
If the clonidine film is removed
and not replaced with a new system, therapeutic
plasma clonidine levels will
persist for about 8 hours and than decline
slowly over several days. Over this time
period, blood plasma returns
gradually to pretreatment
levels. If the patient experiences
localized skin irritation
before completing 7 days of use, the system
may be removed and replaced with a new one applied on a fresh skin
site.
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