I have a lot of occasion to look at the promotional junk drug companies give out, which is always emblazoned with the name and active ingredient of a specific drug. For example, I have a pen in my hand that hypes Zofran, which is ondansetron HCl and an injectable. I also have a Zoloft magnet (“The Zoloft Smile,” which itself sounds like a disease :D), and Zoloft is sertraline HCl.
I can dig up more examples, but those in the know have probably already noticed.
So, why is hydrocholric acid such a common solvent in these drug formulations? I only have high school chemistry, but I can pick things up pretty quick.
further to what antechinus said, most amines are not very water soluble. But the HCl salt is because it is charged, hence dissolves in the water solvent used to inject
The reason the formulas are written and referred to this way is to highlight the parent amine.
A very simple example is the compound ammonium chloride (NH[sub]4[/sub]Cl).
One could also refer to this compound as “ammonia hydrochloride,” which could be written as NH[sub]3[/sub]HCl.
Drugs generally involve far more complex parent amines. BTW, these “hydrochloride compounds” are known as acid salts. These particular salts are useful due to their solubility in water, which makes it easy to get to get the drug into your system when taken orally.
One last point, the cation in these acid salts are weak acids (such as ammonium ion in my example above). There is no actual hydrochloric acid present in the salt.