Hydrochloride

Hydrochlorides of organic bases are salts with hydrochloric acid. Often Hydrochloride salts of primary, secondary or tertiary amines, resulting in a neutralization reaction with hydrochloric acid ( HCl) are form:

The reaction proceeds similarly to the reaction of ammonia with HCl, in which ammonium chloride ( NH4Cl) is formed. Contain all hydrochloride as chlorides, the chloride anion ( Cl - ) and therefore are salts. Hydrochlorides are compared to their parent compounds (mostly amines) usually more soluble in water and can be cleaned easily by recrystallization. The hydrochlorides of amines are more stable and more resistant to aging - as indicated by discoloration - as the free base amines.

For complicated molecules with several basic reacting functional groups ( see alkaloids, lysine ) in which the protonated group does not let you specify hydrochlorides are often represented graphically as follows:

In the reaction of organic diamines with excess hydrochloric acid caused Dihydrochloride (examples: arsphenamine, cetirizine, flunarizine, flurazepam, meclizine and sapropterin ) containing two equivalents of hydrochloric acid ( HCl) salt-like bound.

Use

Many basic drugs are used because of the usually better water solubility and bioavailability as hydrochlorides. Water-soluble salts permit the preparation of aqueous solutions, such as injection and infusion solutions, eye drops, nasal sprays. For oral dosage forms applicable water solubility is often a prerequisite for the release of the drug from the dosage form in the gastrointestinal tract. Only from the dosage form (tablet, capsule, dragee, etc.) released drugs can ever be absorbed. Also technical aspects (stability, solubility, processability ) often play a role for the use of the hydrochlorides of drugs.

Hydrochloride in common drugs applied are for example those of Xylometazolins, ambroxol and metformin. But the European Pharmacopoeia describes well 200 Hydrochloride as drugs, drug - fabric catalog ( ASK) contains more than a thousand hydrochlorides.

Analog salts

The hydrochlorides belong to the class of the hydrogen halides. They also include the hydrofluorides Hydrobromide and hydroiodides.

184357
de