Medical Design Briefs - October 2024 - 12

Transdermal Technology
TRANSDERMAL SYSTEMS
Transdermal patches are medicated
adhesive patches applied to the skin to
deliver a specific dose of medication
through the skin and continuously into
the bloodstream for periods of 1-7 days
per patch. It provides a sustained, controlled
release of the drug, via bypassing
the digestive system and first pass metabolism,
which minimizes the drug plasma
peaks/troughs observed with multiple
oral doses of drug and therefore potentially
reducing side effects.
Delivery Advantages
* Bypass first pass metabolism.
* Potential for fewer side effects.
* Sustained delivery for up to seven days
with a single patch.
Corplex®
, a flexible, transdermal drug-delivery innovation platform, is used in Crest White Strips. (Credit:
Corium Innovations)
Administering Drugs via Patch
So how best to determine whether
a patch system will work for a certain
drug? It starts with a feasibility program,
which takes about four weeks to complete.
Corium Innovations, for example,
has a program called the 1-2-3 Transdermal
Development that is implemented
in three stages:
Stage 1. The first stage takes a customer-provided
molecule and assesses it
against different models through a oneto-two-week
paper screening exercise
that defines the probability of success.
* Assess key drug properties.
* Determine partner/patient clinical
demand.
* Model potential for skin irritation.
* Source quantitative likelihood of formulation
success.
Stage 2. The next stage involves
understanding and generating data
on the solubility and incompatibility
of the drug with respect to specific
components that are typically used in
transdermal application during a twoto-three-week
period for a Solubility
Study that determines:
* Drug solubility in multiple-GRAS excipients
and process aids.
* Gross compatibility of multiple adhesive
mixes.
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* Map prototype formulation from
combined results.
Stage 3. The final stage is to design
a prototype that generates flux data to
a cadaver skin of a human that demonstrates
through evidence that the drug
will be delivered and be able to be absorbed
through a suitable three-to-fourweek
skin flux testing that includes:
* Produce 3-5 patch prototypes.
* Run skin flux testing (N=3) on all test
patch systems.
* Perform physical and chemical testing
of the systems.
* Issue report of generated data and recommendations.
For
scientists, there are screening processes
that are based on several properties
such as molecular weight, predictive
bioavailability, permeation or log P values,
log S values, or partitioning, plus
additional properties. If four or five of
these attributes are met, then it is considered
a viable transdermal option from
a low- and manageable-risk standpoint.
Six-Layer Patch for Alzheimer's
To see how patch technology works
best, a good example is Adlarity, the first
and only once-weekly treatment for Alzheimer's.
Approved by the FDA in 2022 at
5 mg and 10 mg daily doses, the Adlarity
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* Improved patient compliance.
* No fed-fast effects.
* Easier drug administration - no food
effect, eliminates dosing/timing
issues.
* Avoids swallowing issues prevalent with
certain diseases/population.
Added Benefits
* Excellent adhesion/ease of removal.
* Adheres to both wet and dry surfaces.
* Flexibility with natural skin movement.
* Improved drug bioavailability.
patch comes in six layers:
* Layer 1: Overlay backing with adhesive.
* Layer 2: Separating layer.
* Layer 3: Drug matrix.
* Layer 4: Microporous membrane.
* Layer 5: Contract adhesive.
* Layer 6: Release liner.
The
seven-day multi-layer Adlarity
patch delivers in a dose-proportional
manner, which means that there is a 5-mg
strength and the proportional-dose 10mg
strength product that is protected by
Corium Innovations intellectual property
till 2042. Other products are expected
to be developed based on this platform
as well.
Right now, Ozanimod for multiple
sclerosis is under development. Ozanimod
has cardiovascular side effects such
as bradycardia, which is the lowering of
the heart rate to significantly low levels
that could lead to a cardiac event or
acute prolongation concerns.
Medical Design Briefs, October 2024

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Medical Design Briefs - October 2024

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