What does it mean by "turning drugs (in this case, metoclopramide is the drug in question) into hydrochloride salts"? Does it mean hydrochloride chemical is separating the metoclopramide in a water solution?? I don't know anything about chemistry.. can anyone enlighten me to understand the conceptual thing about HCl (hydrochloride) thing that keeps coming up after the prescription drug name? I've heard the part where people say HCl at the end of the drug name stands for the drug into an orally admitted drug (an oral version of the drug), but what's the reason that HCl makes a drug into an oral version of the drug?
Well... not having a chemistry background, I'm not sure how you expect to have this explained to you, but... water is a polar molecule, which means it dissolves salts (electrically neutral compounds composed of positively charged and negatively charged parts that can be separated from each other). If you want to make a molecule, like a drug, dissolve better in water, you can chemically modify it into a salt, so that in water, it dissolves into the actual drug and the anion or cation you modified it to have. The most common way this is done is by "adding" HCl (hydrogen chloride) to the drug molecule, so when it hits your system, it splits into the drug molecule you want, and HCl, which your body can mostly ignore and flush out. The benefit of doing so is a more rapid and even absorption into the blood stream, especially if the drug is taken orally. If you just swallow a glob of an insoluble compound, the absorption rate varies based on the surface area, which means that you basically digest and absorb it more quickly at first (when the surface area is greater) than you do as it gets digested and shrinks in size, so you don't have a constant rate of absorption or a constant concentration in the blood stream... and so you don't poop it out before you've absorbed it all. (And there are often similar considerations for IV drugs, too... it won't do you much good if you have a bunch of chunky drug gobs in an IV that you can't get through the needle, into the blood stream.)
That's basically it, though. Useful drug molecules are transformed into salts, so they dissolve in water so that your body can use them. A more detailed explanation would probably involve you doing your own research and learning ... there are a bunch of education-oriented online video channels you could check out if you want to learn these kind of chemistry concepts, but it's a bit much to go into depth on in this forum. Doesn't really matter for our purposes - that's the oral form of the drug, swallow it 30 minutes before you swallow the thing that kills you, so you don't puke everything up and survive.