Chemistry of Chemotherapy

Hopewell Valley Student Podcasting Network

Chemistry Connections

Chemistry of Chemotherapy

Episode #9

Welcome to Chemistry Connections, my name is Mahisvi Vemulapalli and I am your host for episode #9 called The Chemistry of Chemotherapy. Today, I will be discussing how chemotherapy works in the human body.

Segment 1: Introduction to Chemotherapy

Before we talk about chemotherapy, we need to know what cancer is. Cancer is a disease where damaged DNA results in cells overproducing and spreading to other parts of the body, resulting in the gathering of a tumor. These tumors latch onto the body parts to surrounding cells, growing exponentially in size and taking over the body’s systems. In order to combat cancer, chemotherapy was applied. However, the origin of chemotherapy comes from the discovery of reduced white blood cell counts after people were exposed to nitrogen mustard during World War II. Before you guys get excited about mustard, no, it is not the mustard that you eat. Nitrogen mustard was used in chemical warfare during the war as blister agents. Although the intentions of nitrogen mustard were to harm their opponents, the discovery allowed researchers to start examining the therapeutic effect of mustard agents in treating lymphoma, a type of cancer that arises in the lymph nodes. Though more nitrogen mustard had to be utilized, it was proven that the patient’s tumor masses were significantly reduced, marking the start of the use of cytotoxic agents for the treatments of cancer in 1946. Chemotherapy, otherwise known as chemical healing, started its fame that year. Therefore, as forms of chemotherapy updated and become popularized, there was a decline in mortality rates, making this form of treatment the most common for cancer. Today, we will be focusing on paclitaxel, a chemotherapy drug used for breast, lung, and ovarian cancer.

Segment 2: The Chemistry Behind Chemotherapy

Solubility

However, the mysteries of chemotherapy start from how it is administered. So today, let’s talk about the truth behind paclitaxel. Paclitaxel is a part of the bark of a Pacific yew tree (don’t eat the fruits unless you vomit!), but actually, paclitaxel is actually a tetracyclic diterpenoid, an organic nonmetal compound with a base of 20 carbons, and many more carbonic structures on top of that. In fact, paclitaxel consists of 47 carbons, 51 hydrogens, 14 oxygens, and one nitrogen atom (that’s a lot of atoms!). Based off its molecular structure, this molecule mainly forms London dispersion forces (LDFs), with fewer hydrogen bonds. These hydrogen bonds only occur with the nitrogen and a few oxygen bonds. Though it may seem like there should be more hydrogen bonds, the distribution of the hydrogens amongst the oxygens are dispersed due to the established diterpenoid base with 20 carbons. Overall, this structures causes there to be a greater London dispersion force charge. Paclitaxel itself is originally a fine white powder. In order to administer as an injection, it needs to be dissolved in a soluble solution. Paclitaxel is not soluble in water. This is due to its organic structure that contains mainly LDFs. Therefore, paclitaxel is a nonpolar substance that can only dissolve with other nonpolar substances, like methanol. By dissolving the drug in methanol, it can now be administered as chemotherapy.

Half-life

Now, let’s dive into how chemotherapy works in the body. Paclitaxel itself breaks down in the body by targeting dividing cells. In order to do so, paclitaxel goes through a biphasic decline; it works rapidly and consistently in its first stage, and then travels slower at a constant rate. In its initial elimination phase being the first stage, paclitaxel has a half-life of about 3 to 14 minutes, while in its slower phase, it has a half-life of around 13 to 52 hours. But what is half-life anyway? Half-life is the time required for a substance to reduce to half of its initial value. This means that in the case of paclitaxel during the first phase, it takes between 3 and 14 minutes for the initial dose to be reduced by half. Therefore, when the paclitaxel decomposes into the cells in order to break them down, they initially reduce to a faster constant half-life, and then break down further into a slower half-life. Therefore, once the molecule is fully administered, it can produce the greatest effect.

Segment 3: Personal Connections

It’s important to understand truly how chemical treatments like chemotherapy work on the body, as most people just attribute the treatments to losing hair. However, chemotherapy itself is a wonder, as it one of the most efficient and effective treatments of cancer. Therefore, chemotherapy should not be taken lightly, and instead, it should be researched, so people are aware of the multiple factors that might change their lives. Personally, I enjoy researching medical solutions, and understanding this popular treatment was eye-opening. So next time you hear about chemotherapy, remember its journey throughout the human body.

Thank you for listening to this episode of Chemistry Connections. For more student-ran podcasts and digital content, make sure that you visit www.hvspn.com.