Episode 1: If ADME Were a Trip, T Would Be the Immigration Officer (?)

Quick Intro

So, if you’ve already skimmed through [Episode 0] where we introduced ADMET, today we’ll take a slightly different approach to distinguish between ADME and T.

To make this a little more relatable (or at least memorable 😅), I’m going to use a metaphor — a drug as a traveler on a complex international trip.

(Sure, it might sound a little out of the blue, but your brain tends to remember stories like this better. Trust me.)

What’s the plan for today?

We’ll go over the four stages of ADME as a journey

I’ll briefly introduce key parameters for each stage (just by name)

And most importantly: → Toxicity is not a side note — it’s the immigration officer, the border patrol, the survival judge → It shows up throughout the drug’s journey, not just at the end

Quick Note: Why do we now say “ADMET,” not just “ADME”?

If you look at older papers or lecture slides, you’ll notice the term “ADME” used more often. That’s because:

Until a few years ago, ADME was the dominant framework. But now, Toxicity prediction has become a major part of AI-based drug modeling

Especially parameters like hERG or DILI have a huge impact on model performance. So more and more researchers now naturally include the T — because ADME alone just doesn’t cut it anymore.

Drugs go on a journey

✈ “A drug goes on a journey?”

When you take a medication, it doesn’t just melt into your bloodstream and vanish.

It goes on a journey — through your body, through barriers, through transformation. If we imagine the drug as a traveler, here’s how that journey might look:

ADME Parameters = Key of journey

ADME as a Journey — With Key Parameters

Key ADMET Parameter (simple ver.)

Drug travel is not linear (and neither is ADME)

This journey isn’t a straight 1 → 2 → 3 → 4 → 5 process. Sometimes it looks more like: 1 → 2 → 3 → 2 → 3 → 4 → 3 → 4 → 5 Or even happens in parallel.

Let me give you some examples:

• Metabolism and excretion often overlap (like when your hotel is also the best restaurant in town 🍲🏨)
• Even if absorption is excellent, if the drug can’t cross the BBB, it won’t work for brain diseases
• And sometimes the metabolites themselves become toxic (like buying souvenirs abroad that turn out to be illegal at customs 😅)

Where is TOXICITY (in journey)

So… where exactly is Toxicity?

Toxicity isn’t something you check just once at the beginning or the end. It’s more like a real-time surveillance system — always asking: “Hey, is this drug still okay to proceed?”

“Hey, is this drug still okay to proceed?” (To. Toxicity)

✈ That’s why Toxicity is embedded across the entire ADME journey and not a bonus topic tacked on at the end.

[Wrap-Up]

Let’s end this one clean.

ADME is the drug’s journey to survive. T is the officer who checks whether it can pass through safely.

Core Parameters at a Glance

Cor Parameters (very simple ver.)

Coming up next:

[Episode 2] LogP — The Drug’s Passport?! Understanding Absorption

If LogP determines whether a drug can even enter the body… then is it basically the drug’s passport?

Let’s find out.

Thanks for reading!

This is MGD(Moon Garden).

See you next time :)