The chemical name of salbutamol is 1-(4-hydroxy-3-hydroxymethylphenyl) – 2 – (t-butylamino)-ethanol sulphate.
Its molecular formula is (C13H21NO3)2•H2SO4
Its molecular weight is 576.7
The structural formula of salbutamol is
After oral administration, approximately 50% of salbutamol is absorbed from the intestinal tract with a slower onset of action, reaching a peak at about 2 hours after intake. After inhalation, salbutamol reaches the lungs directly and acts within 3-5 minutes with a peak at 15-20 minutes. Only 10 to 20% of the salbutamol reaches in the lungs after inhalation and the remainder stays in the mouth, stomach or on the apparatus.Overall duration of action of salbutamol is 4-6 hours.
Salbutamol is not bound to plasma protein and does not cross the blood brain barrier to any significant amount. Salbutamol cross the placental barrier, as evidenced by increases in fetal heart rate.
Salbutamol is metabolized in the intestinal tract and in the liver by the process of conjugation with sulphate.
Salbutamol is primarily excreted via the urine. Approximately 50% is excreted as metabolites via the urine and about 30% is excreted as unchanged salbutamol. A small fraction is excreted through the faces.