Henderson-Hasslebalch

Anyone who have studied Chemistry in college or university should have heard of this before. The famous Henderson-Hasslebalch Equation.

Guess what? A band named Unca John's Blues is so free, they made a song about it!



OMG... I'm so going to get a High Distinction for this subject!

Henderson said to Hasselbalch
Got to figure out how most drugs react
Henderson said to Hasselbalch
We got to figure it out
Hasslebalch said to Henderson
What we really need is an equation
Then our names, Messrs. H and H
Will live long after we're dead
Drug molecules almost invariably;
two forms can you find
Ionized or nonionized the pH decides
And the pH where they will be
half ionized
We'll call the pKa
Henderson said to Hasselbalch
Consider the way that weak acids react
When they're totally ionized
They just can't be absorbed
But when they're in acidic
environment, where pH is low
Predominantly they are nonionized
Through membranes they go
And the pH where they will be
half ionized is their pKa
Hasselbalch said to Henderson
Bases can capture a hydrogen ion
In that state, they are ionized and
just can't be absorbed
When they're in acidic
environment where pH is low
They're bound to be totally ionized
absorbtion no no
And the pH where they will be half
ionized is their pKa
Henderson said to Hasselbalch
I think we;ve figured out how most drugs reach
Henderson said to Hasslebalch
I think we've figured out how most
drugs react
Henderson said to Hasselbalch we've
really figured it out
Hasselbalch said to Henderson
We've got ourselves a really nice
equation
And our names Messrs. H and H
Will live long after we're dead.