Aug 30 2009
Image Credits: Dmitriy Rybin/shutterstock.com
Nanotechnology is generally considered as one of the most significant sources of novel technology in the many years to come, and its advancement will have an impact on a wide range of end-users and industries.
Conversely, social, legal, ethical, and policy issues exist that need to be taken into account if the prospective benefits of nanotechnology have to be achieved in a safe and effective manner.
Opportunities for Nanotechnology in Drug Delivery
In the biomedical sector, specifically the diagnostic and medical device fields, drug delivery techniques that utilize the enabling technology of biomaterial and nanotechnology in optical devices are evolving strengths for Australian practitioners.
Today, most drug treatments have an impact on the entire body. A small yet considerable number of cancer patients are known to die from complications because of the toxic effects of radiation therapy and chemotherapy. In biopharmaceutical delivery, there are several traits of nanotechnology that make it an appropriate tool to deal with critical problems:
- Boosting oral bioavailability
- Increased surface area and reduction of particle size, improving solubility
- Vaccine and gene delivery
- Targeting of cells, tissues, and cellular receptors
- Encapsulating drugs in a wide range of nanoscale carriers, like carbon nanotubes or some other kind of molecule
- Crossing of biological membranes, specifically the blood-brain barrier
- Utilizing nanoparticles to penetrate into damaged cells and discharge enzymes that trigger cell repair or initiate the cells’ auto-destruct sequence, called “apoptosis”
- Using drug-eluding coatings on internal medical devices (for example, pacemakers) that can be “switched on and off” via nanomagnets to enable the diffusion of drug molecules into the body
- Adding particular nanoreceptors to drug surfaces to discharge therapeutic drugs precisely where required
- Utilizing nanoporous membranes to regulate time-release delivery of drug molecules, enabling a continuous rate of diffusion
- Offering more improved performance via nanoparticles (for example, pain reliever Aleve)
In March 2004, a market analysis was carried out, which recommended “Nanotechnology is currently applied in ~1% of drug delivery technologies under development; by 2015, ~14% of drug delivery technologies may use nanotechnology.”
Pulmonary Drug Delivery
There has been an increasing interest in the potential for the strategic delivery of therapeutic agents and drugs (for example, proteins and peptides) through pulmonary (inhalation) means. When compared to oral administration or other invasive delivery methods, pulmonary drug delivery provides an attractive option.
Fluids can be atomized as accurately controlled droplets with the help of pulmonary drug delivery based on Surface Acoustic Wave (SAW) technology. Upon activating the device, an electric field applied to the electrode surface creates an acoustic wave. After the drug is added to the electrode in the form of a liquid droplet, atomization takes place, creating nanoparticles or microparticles, which continue to remain as a liquid. The particles’ size can be suitably regulated by the electrode design as well as the electric field’s properties.
The nanoparticles can be subsequently inhaled into the lungs, where they are guided across the pulmonary alveoli and are finally absorbed into the bloodstream. When compared to injected insulin, this enables better efficacy of inhaled insulin because of faster uptake and clearance.
In particular, pulmonary delivery is preferred for several frequent-application drugs, like insulin for diabetics who have to inject on a day-to-day basis. Other benefits include delivering drugs in a pain-free and non-invasive manner, administrating small and large molecule drugs, as well as the potential to closely regulate drug dosage. The technology can also be packaged in a consumer-friendly compact personal inhaler, with an eye for increasing patient compliance.
In transdermal delivery, large biopharmaceutical molecules are delivered painlessly across the essentially impermeable skin’s outer layer via skin contact with topologically undulating patches like MicroArray patches.
MicroArray patches offer a pain-free and effective delivery system for large-sized molecules like hormones, DNA, drugs, proteins/peptides, and vaccines. Eventually, the MicroArray patches can be utilized by health care professionals and non-specialized personnel like animal owners, farmworkers, or the general public.
MicroArray patches include arrays of solid micro-protrusions developed from polymers that are biocompatible and/or biodegradable. The reagents meant for delivery are fixed to the MicroArray patch’s external surface, incorporated into the polymer or both. Upon applying the patch, the microneedles cross the stratum corneum and enter the epidermis. The microneedles do not enter sufficiently deep to penetrate the nerves or blood capillaries; therefore, the delivery is pain-free and non-invasive.
The MicroArray patch allows direct access to the cells of the immune system, and thus their potential in vaccination. Through transdermal delivery, drugs can be delivered in a systemic manner, dodging the gastrointestinal tract and the first-pass metabolism of the medication in the liver. As liver metabolism is prevented, lower doses of the drug can be utilized and thus liver toxicity can be decreased.
The MicroArray patch consistently discharges the drug over an extended period, producing steady-state blood levels and reducing dosage troughs and peaks. These, in turn, increase efficacy, reduce “break-through” events, and decrease the frequency and incidence of side effects. The MicroArray patches are suitable for drugs that have short half-lives, those that are too strong to be orally administered, or those that are not well tolerated through inhalation.
The MicroArray patches are easier to use when compared to conventional drug delivery systems. The patches not only eliminate the pain and trauma related to needles but also decrease the risk of infection. However, delivery from these patches is short term because the micro-protrusions are naturally shed from the skin within a period of three weeks.