drug delivery
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Customized Adhesive
And CoAting
teChnologies
enAble novel drug
delivery methods
Pharmaceutical-grade pressure-sensitive adhesives (PSAs) have played a critical role in the function and accurate
delivery of transdermal drug delivery systems (TDDS) ever since the launch of the scopolamine transdermal patch in
the late 1970s. Most drug delivery development projects begin by considering an existing base adhesive technology.
However, the end result is typically a customized adhesive based on application design input and the requirements
of each customer’s manufacturing process. New advances in adhesive technology during the past 10 years have
opened up new windows of opportunity for the development of transdermal delivery products, encompassing many
new and exciting applications that would have been unheard of just a decade ago.
lthough transdermal patches offer many advantages, passive a sustained immune response. When considering adhesive and
systems are restricted to low-dosage lipophilic and low component materials for this type of delivery system, formulators
molecular-weight molecules (<500 Daltons).1 Much of the must ensure the proper chemical compatibility of these materials
current growth for transdermal drug delivery is focused on with the device’s proteins and active ingredients. In addition, the
active systems to deliver a wider range of drug molecules, including proteins materials should not contain any biocides or toxic leachables that
such as vaccines. As transdermal product designs and capabilities continue could potentially denature proteins or interfere with biological activities
to evolve, adhesive manufacturers are embracing new opportunities to or targeted immunization response. Skin-contact adhesives should
formulate highly specialized pressure-sensitive adhesives (PSAs), coatings demonstrate good wear properties and moisture control to prevent
and related polymer technologies to meet the requirements of these lateral movement of the vaccine, which could alter dosage and
delivery systems (Table I, Figure 1). decrease device efficacy.
Needle-Free Vaccine Delivery AS DevelOPerS exPlOre Iontophoretic Drug Delivery
The needle-free delivery of therapeutics and PSAs perform multiple functions in iontophoretic
vaccines can potentially address the growing
New MeTHODS Of drug delivery systems, including bonding to the
global issues associated with diseases skin, creating a protective seal and forming
that are passed intravenously through the DeliveriNg DrugS, PSA conductive bonds for internal electronic
improper use and disposal of needles. component assemblies. Iontophoretic devices
Patch-based needle-free immunization MANufAcTurerS will offer a non-invasive alternative for delivering
systems for the safe and convenient delivery therapeutic substances via the electrotransport
of vaccines are currently in clinical trials.2 The cONTiNue TO PuSH THe of molecules that would not normally diffuse
construction of the vaccine patch is similar across the skin. A small electric current passes
to that of a transdermal patch, but contains cAPAbiliTieS TO MeeT THe through the patient’s skin, between positively
an antigen and an immune-boosting adjuvant and negatively charged electrodes. The drug
to stimulate the body’s immune system. The uNique cHAlleNgeS Of or active substance is located at one of the
patch works by delivering the vaccine to a electrode sites, depending upon the drug’s
group of antigen-presenting cells in the skin New AND eMergiNg polarity. The active electrode repels the charged
called Langerhans cells, which transport the drug, forcing it into the skin by electrorepulsion,
vaccine to nearby lymph nodes to produce APPlicATiONS. where it is picked up by the blood or lymph
Sept/Oct 2009
drug delivery
www.pharma-mag.com
Adhesive Description Chemistry Functional Properties for Drug Delivery
Skin-friendly PSAs