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Nanomedicines is a very young branch of science. It has come into the picture only since the 1990s. Wonder what made researchers go down the nanoscale when we already had various drug development systems? The basic flaws in the conventional drug delivery system provided the spark for the emergence of a nano-drug delivery system.

 When we swallow a pill, its contents are constantly lost or tampered. This may be because of the acidic environment of the stomach, detoxification properties of the liver, or due to the presence of proteins and enzymes in the bloodstream which may bind to the drug and change its physiological properties. As the loss at these barriers is very high, a massive dose is required to compensate for this loss. According to David Anderson, a neurobiologist, current medication is like pouring a can of oil all over your car engine. Some of it will dribble into the right spot, but most of it is wasted, and some even does harm. This is the reason why chemotherapy patients lose hair. The drugs are so toxic that they not only affect but also kill normal healthy cells.

These problems can be dealt with if the delivery system of these drugs is altered. This is where nanoscience emerges as a potential solution. Nanomedicines are manufactured on a scale of 10^-9 m and can be even smaller than a virus! Due to its peculiar size, it can exude properties of both quantum and Newtonian mechanics thereby adding to the number of benefits we can avail. Moreover, its surface to mass ratio is exceedingly large, hence, it has the ability to bind, absorb, and carry various compounds. Coating them may also be necessary to prevent agglomeration. This can be done with various substances, such as natural, synthetic, inorganic, etc. To reach only the target site certain compounds are added which function as "Molecular keys". This technology is being harnessed mostly for the treatment of brain cancer as it is one of the most difficult malignancies due to the presence of blood brain barrier which tightly regulates the movement of molecules and ions between blood and brain. Nano-medicines recognize specific markers on cancer cells and their size opens the potential for crossing various biological barriers thereby increasing their efficacy. Anti-cancer drugs such as loperamide and doxorubicin bound to nanomaterials have been shown to cross the intact blood-brain barrier and released at therapeutic concentrations in the brain. In most cases, resistance develops when cancer cells begin expressing a protein, known as p-glycoprotein that is capable of pumping anticancer drugs out of a cell as quickly as they cross through the cell's outer membrane. New research shows that nanoparticles may be able to get anticancer drugs into cells without triggering the p-glycoprotein pump. The researchers studied in vivo efficacy of paclitaxel loaded nanoparticles in paclitaxel-resistant human colorectal tumors. Paclitaxel entrapped in emulsifying wax nanoparticles was shown to overcome drug resistance in a human colon adenocarcinoma cell line (HCT-15).

Many questions are still raised on the safety and cost of the nano-drug delivery system. Therefore, it remains irrefutable that the development of more sophisticated designs and further understanding of the properties at the nanoscale are required to yield such advanced therapies.

Citations:

·       https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2222591/

·       https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2527668/