Drug Metabolism

Introduction

Hello everyone, my name is Paras Thakan. I am now pursuing a Master of Pharmacy in the field of Pharmaceutical Analysis. I'd love to talk about the role of medication metabolism. You might be wondering why the topic is CYP450 and I'm talking about drug metabolism. Before discussing the significance of CYP450 microsomal enzymes, it is critical to first understand drug metabolism.

What is Drug Metabolism

Suppose you have a fever and take paracetamol. Have you ever wondered what happens to a medicine once it enters the body? The answer is simple: when paracetamol enters your body, it diffuses into the bloodstream and reaches your liver. The medicine is active in the liver and becomes inactive because of enzymatic processes before being eliminated in your body via urine. Drug metabolism refers to the process by which a drug transitions from an active to inactive state.

 Why Drug Metabolism?

1. Certain metabolites produced after medication reactions can induce serious pathological abnormalities.
2. Drugs have adverse effects, thus it is important to ensure they are eliminated from the body

Phase - I Drug Metabolism

The liver is the primary site of phase I drug metabolism in your body. During this phase, the drug reaches the liver and experiences significant structural changes due to oxidation and other processes such as reduction and hydrolysis. This causes the medication to become more hydrophilic (water soluble) rather than lipophilic. This increases the drug moiety's polarity.  

Phase - II Drug Metabolism

Some medicines may not become polar despite structural modifications during Phase I drug metabolism. To address this, in Phase II drug metabolism, proteins or glucuronic acid are conjugated to the drug moiety. The drug metabolite is mostly formed by the addition of glucuronic acid. This phase renders the drug metabolite inactive and more polar, allowing for easier excretion of the medication through urine.

Conclusion

I'd like to end by noting that you now have all of the basic knowledge needed to understand the role of the CYP 450 enzyme. Drug metabolism is the process by which a drug moiety transitions from an active to an inactive state via specific enzyme processes.
It occurs in two phases.

1. Phase I: The drug's structure changes through oxidation, reduction, or hydrolysis to become more polar.
2. Phase II: The drug is coupled with glucuronic acid and proteins and becomes inactive.