Nanomedicine and nanotechnology delivery systems are relatively new but have shown promising results and potential for innovative new drugs. Nanoscale materials can be used as diagnostic tools or aid in targeted and controlled delivery of previously challenging to administer drugs. Work is being undertaken to understand nanomedicine’s potential application in numerous disease areas, including cancer, diabetes, neurodegenerative diseases, and vascular diseases.
Nanomedicines for Cancer
Nanomedicine has the potential to overcome problems with other forms of cancer treatments and has made significant contributions to oncology in the past few decades. The most common cancer treatment used today is chemotherapy. The major drawback to this method is that chemotherapy drugs not only kill tumour cells but kill other dividing cells causing undesired side effects. Additionally, the remaining drugs that manage to reach the tumour after passing through biological barriers are often not enough to penetrate tumour cells effectively.
Liposomes were the first class of therapeutic nanoparticles to receive clinical approval for cancer treatment, along with other lipid-based nanoparticles, and still represent a large proportion of clinical-stage nanotherapeutics drugs.
Using nanotechnology, chemotherapy can target a tumour more effectively while decreasing exposure to the rest of the body. However, with that said, current nanomedicines need to be better targeted to destroy cancerous tissue specifically. Currently, several challenges in their clinical development hinder specificity, including problems identifying appropriate biomarkers to target, scalability, variability, and reproducible characterisation.
Improving the effectiveness of cancer therapies is a priority for many pharmaceutical companies and the promise of nanotechnologies to focus delivery to the tumour tissues is enticing despite the challenges. Current treatments have already displayed the ability to deliver smaller therapeutic doses in a sustained manner over time and improve drug penetration into the tumour tissue. Nanoparticles can be designed with specialised surface coatings to break through biological barriers and allow penetration through the tissue to allow higher doses of a drug to reach tumour cells.
Improving Drug Delivery: Nanomedicine and Solubility
Recent trends in drug development have been making delivery more challenging, requiring innovative new methods. Professor Moein Moghimi (Professor of Nanomedicine, Newcastle University) explains that “a lot of molecules from industry are becoming larger and larger, more and more insoluble, and you need to find new ways of solubilisation” and that the solution lies in technologies such as “nano crystal technology and hydrogels are areas that nanomedicine could flourish and help the industry.” Generally, larger molecules, which are increasingly prevalent, are usually less soluble, hindering drug delivery. It is estimated that over 80% of pharmaceutical pipeline API’s are poorly soluble in water.
Another challenge is delivering therapies through the blood-brain barrier (BBB). This protects the brain from foreign substances and blood-borne infections, but it also makes it challenging for therapeutic compounds to be delivered in an efficient way. Due to this, high doses must be administered, with increased risks of adverse side effects. Among the different approaches explored in recent years to overcome the delivery challenges is the application of nanoparticle-based systems ranging from polymer particles to liposomes & administering these through the BBB. A major breakthrough has been the development of peptide self-assemblies (also known as NanoLigand Carriers) for the delivery of nucleic acid medicines to neurons and microglia on intravenous administration showing unprecedented pharmacological activity and safety.
Nanomedicines: Future Goals & Priorities
Nanomedicine approaches, especially for cancer therapies, have often led to underwhelming results when translated from the pre-clinical to the clinical arena due to the complex and still poorly understood nature of the nano-bio interactions.
Several key areas have received a great deal of attention. One is determining the distribution of nanoparticulate carriers in the body following systemic administration through any route.
New imaging modalities are required to provide a clearer picture of biodistribution. While a variety of molecules have been used previously in nuclear imaging, the exceptional properties of nanostructures in recent research enable the deployment of accurate and efficient diagnostic agents using radionuclide-nanostructures. In addition, understanding how an administered drug spreads through the body are essential for ensuring safety and avoiding off-target effects.
Another goal is increasing understanding about what makes individuals respond differently to the same drugs. Varied responses and individual differences are posited to be a significant part of why nanotechnologies cannot always improve the therapeutic output of medications for every patient. Therefore, understanding how nanomedicines react when encountering different physiological characteristics of patients and their disease states will be crucial to increasing adoption.
The use of nanotechnology in medicine offers a variety of exciting possibilities. While many techniques are only in the early stages, progress is being made, and several nanomedicines are currently being used or are going through trials. Scientists have set ambitious goals to increase understanding of nanomaterials and nano-bio interactions, and while there is much left to discover, the pace of discovery has increased over time. The area has been evolving fast and we are yet to see their full power revolutionising research.