Writer: Natasha Matta
Hypodermic needles currently being used for drug delivery and vaccines are invasive, painful and inefficient, and they can damage blood capillaries or nerve endings if administered incorrectly and risk skin infection. Microneedles, microscopic spikes/applicators, are designed to puncture certain layers of the skin (usually the outermost one) to deliver a treatment. This procedure is minimally invasive and does not incur the risks of traditional methods of drug delivery, such as accidentally coming into contact with a blood capillary or damaging a nerve.
Additionally, microneedles are oftentimes psychologically better for patients. People needing to receive a vaccine or drug may be needle-phobic, especially young children, and so, less intimidating microneedles may improve patient compliance, making it an easier process for both the patient and healthcare professional.
Microneedles come in four different types: hollow, solid, polymer and coated, and they are applied through patches or implants. Hollow microneedles infuse a drug through small holes, solid microneedles create larger, deeper puncture holes in the skin to increase permeability where the medication is delivered, polymer microneedles come in dissolving, non-dissolving or hydrogel-forming options, allowing for better adhesion and site-specific drug delivery, and coated microneedles have a treatment on their surface. Greater customization with the four types of microneedles and different methods of application allows for more effective and targeted drug delivery (e.g. administering a drug near an area of high inflammation rather than it circulating through the entire bloodstream) and less risk (e.g. choosing a microneedle which only punctures a specific layer of skin and stronger adhesion to the skin mitigates risk of injury and injection into the incorrect layer of the skin). Patches allow medication to be easily and quickly absorbed into the bloodstream, and implants create a port for drugs to be easily delivered and systematically distributed.
Receiving a vaccine is usually a small inconvenience every few months or years, but for serious ailments, patients can require daily, weekly or monthly hypodermic injections, which often lead to pain, bruising and heightened sensitivity at the injection site. Transdermal microneedle patches are virtually pain-free and can be self-administered, likely resulting in improved medication compliance.
In addition, drug delivery is more effective transdermally than hypodermically, and this trend becomes even more apparent over an extended period of time. Orally administered drugs travel through the metabolic system of the liver, eliminating a large amount of the medication before widespread distribution. In contrast, administration through transdermal devices requires a lesser amount of drugs for the same efficacy of delivery. Patches and implants using microneedles can deliver a continuous flow of the active ingredient of a medication for long periods of time, as much as 24 hours or 7 days straight. Doctors can ensure patients are receiving the correct dosage at a specific time of day instead of relying on a patient to remember to take a pill at a certain time everyday.
Microneedles are more effective than hypodermic solutions for immunization: administering a vaccine through a transdermal patch is more effective in initiating a defense response to protect the body. Overall, microneedle patches and implants allow for site-specific, highly effective drug delivery, better autonomy of patients, stronger immune responses, customization for the individual, and incur less pain, discomfort, bruising and sensitivity than with a hypodermic alternative.
After establishing the insufficiencies with current methods (hypodermic needles), the author introduces a safer and more effective method of drug delivery (transdermal microneedles). She approaches the issue of vaccines and drug delivery from several different perspectives and considers various aspects, thoroughly explaining how microneedle patches and implants are better for patient psychology and compliance, site-specific and effective drug delivery, customization, and immunization properties. Her work is not based on conjecture but backed by research, which she cites. The writer used reputable sources including research papers from peer-reviewed science journals and wrote professionally, using third person and employing correct spelling, grammar, and formatting.
Figure 1. Microneedle drug delivery patch
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