ipratropium bromide hydrate

Ipratropium bromide monohydrate (Ipratropium bromide hydrate) is a muscarinic antagonist structurally related to ATROPINE but often considered safer and more effective for inhalation use. It is used for various bronchial disorders, in rhinitis, and as an antiarrhythmic.

Tiotropium Bromide hydrate (BA-679 BR hydrate) is a potent anticholinergic and bronchodilator, serving as a muscarinic receptor antagonist, specifically targeting mAChR. It is developed for treating chronic obstructive airways disease (COPD), demonstrating novel and long-lasting effects. Binding studies with [3H]tiotropium bromide in human lung reveal its high potency and equivalent affinity for M1-, M2-, and M3-receptors, making it roughly 10 times more effective than ipratropium bromide. It notably inhibits cholinergic nerve-induced contraction of both guinea-pig and human airways more potently than atropine or ipratropium bromide, albeit with a slower onset. Tiotropium bromide uniquely presents slow dissociation from M3-receptors on airway smooth muscle and rapid dissociation from M2 autoreceptors on cholinergic nerve terminals. As a quaternary ammonium derivative, it shows high affinity and special kinetic selectivity towards muscarinic receptors across M1-, M2-, and M3-subtypes, due to its slower dissociation from M1- and M3-receptors compared to M2-receptors.