When designing a drug delivery system based on polymeric particles, it is important to consider if micro-scale or nano-scale sized particles should be used. Though both sizes are very small, there are actually significant differences between them that affect their functionalities.
Nanoparticles are particles with sizes smaller than 1 µm. Their extremely small size results in a high ratio of surface area to volume. This ratio promotes a high degree of surface adsorption by drugs, proteins, and other molecules. It also allows for increased interaction with other particles, which leads to changes in physical properties. The small size of nanoparticles provides other benefits, as well. For example, nanoparticles can be made aggregation free, making them useful for intravenous or systemic drug delivery. They are also more likely than larger paticles to bypass the reticuloendothelial system as well as biological barriers (like the blood brain barrier). They can additionally enter all cells via pinocytosis. Furthermore, nanoparticles can be manufactured and produced in sterile form.
Microspheres (sizes can vary from 1 µm – 1 mm) are also frequently used in drug delivery systems and have their own advantages. Because microspheres are larger than nanoparticles, they are able to encapsulate a larger amount of drugs or other molecules. Though they cannot easily be used for intravenous or systemic delivery (because they could agglomerate and cause clotting), they are effective for local delivery, like subcutaneous injection, and can be used in sustained release systems. Phosphorex can manufacture both nanoparticles and microspheres. Our technical support team is happy to discuss your project with you and answer any questions you may have.