The dissolvable microneedles infused with ethanolic lipid nanoparticles loaded with the drug benidipine, which were shown to be effective in delivering the anti-hypertensive drug in rats. — Dr SYED MAHMOOD
Microneedles are micrometre-sized (µm) needles arranged on microneedle devices in the form of a small patch.
They can gently penetrate the skin without causing pain, making it a better alternative than the usual syringe that is used in hospitals, especially for patient compliance with medication.
Microneedles have a predefined size and shape that allow them to penetrate the stratum corneum (the outer layer of our skin), which is about 10–20 μm in thickness.
They are a transdermal drug delivery platform that can be used to treat various diseases.
Transdermal means that the delivery is done through the skin and into the blood circulation.
This pathway is preferred as it is a painless approach to deliver drugs into the blood vessels located beneath the skin, while bypassing the hepatic first-pass effect (i.e. the effects of liver metabolism).
Microneedles are very much in use nowadays, especially in aesthetic medicine clinics for procedures to treat skin conditions like acne, scars and wrinkles, as well as in certain hair growth procedures.
Over the last two decades, they have also been studied and researched extensively for use in other medical procedures.
These include the delivery of vaccines, RNA/DNA, insulin, hormones and other drugs for medical conditions like HIV (human immunodeficiency virus), glaucoma, infections, cancer and many more.
Many patents have been registered and many clinical trials are actively testing microneedles for the potential human use.
Recently, our research group in the Faculty of Pharmacy at Universiti Malaya completed a study on dissolvable microneedles infused with ethanolic lipid-nanoparticles loaded with the drug benidipine.
Benidipine is commonly prescribed for the management of hypertension (high blood pressure) and angina pectoris (chest pain or discomfort due to coronary heart disease).
The dose of the tablet is usually 2-4 milligrammes daily, gradually increasing to 8mg according to need.
The purpose of using microneedles to deliver drugs such as benidipine is to enhance their efficacy, increase solubility and reduce the side effects.
Working with fellow researchers from Universiti Malaysia Pahang Al-Sultan Abdullah and International Medical University, we used dissolvable microneedles, which are made using specialised materials that will dissolve in the body after use.
To prepare our dissolvable microneedles, we used a lab-based hyaluronic acid.
Hyaluronic acid is a natural substance found in the fluids in our eyes and joints.
Our study found that our microneedles were capable of delivering benidipine in the required amount using the animal model.
The microneedles integrated with benidipine nanoparticles had sufficient mechanical strength, good insertion capability and fast dissolution when tested on rat skin.
The relative bioavailability of benidipine was also improved by about 1.58 times compared to the tablet form.
In conclusion, benidipine-loaded lipid nanoparticles integrated into dissolving microneedles have shown high potential as carriers for the transdermal delivery of this drug over oral delivery.
We believe that our study, published in the science journal Surface and Interface in August (2024), is the first reported from a Malaysian university on dissolvable microneedles involving hypertensive drugs in animals.
We hope to continue our research with these benidipine-loaded microneedles in larger animals like rabbits and guinea pigs.
Our research group is also working on using microneedles to deliver insulin, as well as other drugs for HIV and cancer.
Dr Syed Mahmood is a senior lecturer at the Department of Pharmaceutical Technology in Universiti Malaya. For more information, email starhealth@thestar.com.my. The information provided is for educational and communication purposes only, and should not be considered as medical advice. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this article. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.
