COPD MDI Salmeterol xinafoate Competitive price manufacturer producer factory in China CAS NO.94749-08-3

It is a long-acting beta₂-adrenoceptor agonists (LABAs), usually prescribed only for severe persistent asthma following previous treatment with a short-acting beta₂-adrenoceptor agonists(SABAs) such as salbutamol (albuterol) and is prescribed concurrently with a corticosteroid, such as beclometasone dipropionate or fluticasone propionate. The primary noticeable difference of salmeterol from salbutamol is that the former's duration of action lasts approximately 12 hours in comparison with the latter's 4–6 hours.

When used regularly every day as prescribed, inhaled salmeterol decreases the number and severity of asthma attacks. However, like all LABA medications, it is not for use in relieving an asthma attack that has already started.

Inhaled salmeterol works like other beta 2-agonists, causing bronchodilation by relaxing the smooth muscle in the airway so as to treat the exacerbation of asthma. The long duration of action occurs by the molecules initially diffusing into the plasma membrane of the lung cells, and then slowly being released back outside the cell where they can come into contact with the beta₂adrenoceptors, with the long carbon chain forming an anchor in the membrane. Interestingly, salmeterol binding to the beta₂-adrenoceptor does not induce desensitisation or internalisation of receptors which may also contribute to its long therapeutic duration of action. Formoterol has been demonstrated to have a faster onset of action than salmeterol as a result of a lowerlipophilicity, and has also been demonstrated to be more potent—a 12 µg dose of formoterol has been demonstrated to be equivalent to a 50 µg dose of salmeterol.