What I Learnt from the Pharmacy: Questions & Curiosity

This post is a follow up to my pharmacy work experience diary which you can read here if you'd like to know more about what I actually did during the week.

During my pharmacy work experience, I found myself asking so many questions!! I wanted answers, and I managed to find quite a few through my own research and help from my chemistry teacher. These are some of the questions that stuck with me most, and what I learned from asking them or looking them up:

Why do some medicines need to be stored in the fridge?

I noticed that certain medicines were kept in a fridge, often things like insulin, antibiotics and vaccines. This is because they need cold temperatures to stay effective and if they get too warm they can break down and stop working properly/as effectively. Thats why pharmacies are so careful with how these are stroed and why they are often kept in the fridge right until a patient arrives to collect it.

Why do some medicines come with warnings about food, driving or alcohol?

Some packets had warnings on them saying 'do not take with dairy' or 'may cause drowsiness - don't drive'. I found out that this is all about how medicines interact with our body. For example, some tablets don't absorb properly if you take them with milk because calcium blocks them (now I understand why I can't drink milk with iron tablets!) and others make you sleepy because they can affect the brain.

What does a 'controlled drug' mean?

This was one of the first questions I had, as big red stickers saying 'Controlled Drug' are pretty difficult to miss! The pharmacist explained that controlled drugs have a higher risk of being misused or causing harm if not used correctly - things like morphine or certain strong painkillers. This means that they were locked away seperately, and if they were being delivered but the person was not home, they would not be put through the letterbox or given to anyone else and they would be delivered on another day.

How do chemists choose which functional groups to add?

This was a really cool question to think about because functional groups (like OH, C-C single bond, C-C double bond, COOH) can decide so much about how a molecule behaves, like whether it's soluble, how easily it gets into cells, or how its broken down.

I found out that chemists might add polar groups to make a drug more water-soluble so it can travel in the bloodstream, or add a methyl group to block a certain reaction in the liver. Some groups can make the drug stick better to its target or help it survigve long enough in the body to do its job.

What makes drugs expire?

While doing date-checking during my work experience, I started wondering what actually causes the drug to expire. I found out that the two main reason why medicines expire is because of chemical breakdown and contamination. Some drug molecules are unstable and slowly break down, expecially if they are exposed to heat or moisture or light. This is called chemical degradation and it means that the drug may become less effective or even unsafe. In other cases, especially with liquids or creams, microbial contamination is a risk once the seal is broken. That's also why storage instructions like 'store in a cool dry place' are so important because they help preserve the chemical structure of the drug/

Why do some drugs have shorter shelf lives than others?

Some drugs only last a few months but others are stable for years, and this often depends on how reactive the molecule is. For example, medicines that contain unstable bonds or are easily oxidised usually degrade faster. Otheres might break down in light, especially UV light which is why some medicines come in dark or amberish colour packaging. Water based formulations also tend to have shorter shelf lives than dry tablets because water encourages bacteria to grow and speeds up chemical reactions. Basically, the more sensitive a drug is to its senvironment, the shorter its shelf life will likely be.

What does gastro-resistant mean and how does it work?

Gastro-resistant drugs are medicine which are designed specially to survive the acidic envrionment of the stomach and only release the active ingredients once they reach the small intenstine. This is important because some drugs can be damaged or deactivated by stomach acid, while others may irritate the stomach lining if they get resleased too early.

The way that these drugs work is that they are coated with pH sensitive polymers that don't dissolve in the stomach's low pH (1-3) but do dissolve in the higher pH of the small intestine (6-8). This coating is kind of like a chemical sheild which protects the drug as it passes through the stomach and then it only breaks down once it reaches a safer environment.

This ties directly into pharmacokinetics which is the study of how the body absorbs, distributes, metabolises and excretes a drug. In order for a gastro resistent drug to be effective, it must be absorbed in the intestine after the coating dissolves. If it is released too early, it could be destroyed before absorbtion orfail to reach the bloodstream at the right time or place. So designing a drug to be gastro-resistant is a key way of controlling when and where the drug enters and works in the body, which is a key part of making it work properly.

What surprised me most during my week in the pharmacy wasn't just how many medicines there were, but how many questions they made me think of. Almost every task, every drug and every label left me wondering why or how something worked. This work experience made me realise even more that curiosity is one of the most powerful parts of learning. It's what turns everyday observation into real science, and I'm excited to keep following where my curiosity leads me next.