Drugs, Structures and Pharmaceutical Terminology

Question

I'm currently completing an assignment for my Year 11 Biology class. We have to explain how certain drugs affect the body and (chemically) why, however I’m confused about the actual structures and names of many for the drugs. One of the drugs I’m studying is methylphenidate, which when you wikipedia it, shows its structure with two rings, one with a carboxylic group (O=C-OH) on its end. However on other websites when you look up methylphenidate, it comes up with a diagram of methylphenidate hydrochloride, where the OH is replaced with an OCH3 and shows a HCl next to it for the reaction. They also refer to it as straight methylphenidate?... Similarly my friend is doing clorazepate, but the search comes up with “clorazepate, also know as tranxene”, which is actually clorazepate dipotassium, again a different structure featuring a . KOH.

What does this mean? Is one its actual structure and the other how it comes as a drug, with another substance that will react to form the original straight drug? Any help is greatly appreciated!

Answer 1

Organic compounds such as drugs are often packaged with inert substances like hydrochoride or potassium salts to maintain their efficacy (effectiveness or potency).  You can *probably* trust the Wikipedia structure, the article is well referenced.  So that is the structure that somehow interacts with the protein structure of the dopamine transporter (as far as I can tell) to block uptake of dopamine, which has the effect of increasing activity in other parts of the brain... counterintuitive because Ritalin is used for ADHD.  That's my interpretation, hope this helps.