The compounds are similar to hydrochlorides. Converting insoluble amines into hydrochlorides is a common way to make them water-soluble. The European Pharmacopoeia lists more than 200 hydrochlorides as active ingredients in medications. In addition, many hydrochlorides of amines have a longer shelf-life than their respective free bases. Ammonium salts formed from the acid-base reaction with hydrochloric acid are known as hydrochlorides.