Transdermal Patches and Their Working

Having a powerful attitude, prolific mindset, and put under a magnifying glass test-and-adapt approach is the definitive way to stay firmly in front of any racing – and it’s a sure bet against becoming complacent. This dynamic mindset and out-of-the-box thinking made researchers develop something new, not the conventional one and this leads to the development of “Transdermal Patches.

It’s interesting to know how efficiently transdermal patches are designed to deliver medications through the skin. Transdermal Patches deliver a continuous amount of medicine over a period of time. Patients use transdermal patches to get relief from severe chronic pain. 

How do Transdermal Patches work

To foster a fruitful medicated transdermal patch, it requires a significant degree of effort, resources and technical expertise. 

Multiple layers are associated with transdermal patches, described as follows:

1. Innermost adhesive layer – This layer attaches/adheres to the skin.

2. Rate-controlling micropore membrane – The rate of drug delivery to the skin surface is controlled by this layer.

3. Main drug reservoir layer – The active drug to be delivered is contained in this layer.

4. Outer backing film – an occlusive supporting layer

Not only limited to these layers, the addition of permeation enhancers, stabilizers and packaging are equally needed to effectively design transdermal patches. As a carrier, a transdermal patch holds the drug until the point of application and then the adhesives allow the drug to permeate through the skin.

Now, let us look into a few checkpoints before administration of any Transdermal Patches:

• Whenever we are going to administer transdermal patches, we need to check for respiratory SOS and blood pressure in order to determine the right location where the patch can be applied for resulting an effective action.
• Selection of the right patient to get the patch administered
• Watching out for the right drug, dose and its timing as per the physician’s order
• Ensuring the ‘Sealed’ condition of the package to confirm no damage or tampering inside
• Ensuring the usage of the drug within the expiration date 

‘Mandatory Checks’ before administering Transdermal Patches:

Never administer medication without the proper credentials or authorizations. Always follow the latest news and employer protocols in your area for proper medication administration, storage, and disposal.

Advantages of Transdermal Pathes

• Provides continuous plasma concentration of drug 
• pH variations seen with gastrointestinal transit can be avoided with drugs administered through the skin 
• First-pass hepatic metabolism can be avoided with drugs administered through the skin. 
• Self- administration of the patch is possible. 
• Drugs delivery is performed in a non-invasive way without causing any pain 
• Increased bioavailability
• Systemic side effects are less 
• Reduced drug-to-drug interactions 

Shortcomings of Transdermal Patches

• Expensive solution 
• Chances of getting local irritation, rashes, or contact dermatitis by the use of the patch. 
• Limitation due to the small pore size of the skin, and the skin’s impermeability, only potent drugs can be chosen as suitable candidates for transdermal patches. 
• To cross the Stratum corneum layer of the skin effectively, only drugs with a lipophilic character and desirable physicochemical properties are suitable candidates for transdermal patches. 
• Dose limitation up to 5mg or less can be administered in a day. 
• Skin’s barrier function changes from one site to another on the same person, from person to person, and with age. 
• Adherence of the patch can be a problem depending on all types of skin, can become uncomfortable to wear as adhesives 
• The transdermal route does not facilitate the delivery of ionic drugs. 
• There are chances that the patch may fall off being unnoticed. 

Developing a successful transdermal patch and its applications

The design and development of an ideal transdermal patch is a significant endeavor. This technology brings large benefits to the patients by helping them avoid the inconvenience of parenteral therapy as well as invasive routes. Transdermal patches are becoming increasingly popular over medicines in the form of pills or shots. A few of the noteworthy applications of transdermal patches include a Nicotine patch to help with the cessation of tobacco smoking, a Fentanyl patch to relieve pain, and Estrogen patches to treat menopausal symptoms. The introduction of transdermal patches paved the way for new medical therapies while serving as a better alternative compared to oral drugs and thus benefiting a million users every year.

Anuj Pathak

Assistant Professor

KIET School of Pharmacy

Ghaziabad, India

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