Comparative Bioavailability and Pharmacokinetics of Three Formulations of Albuterol

Albuterol sulfate, α′[[(1,1-dimethylethyl)amino]methyl]-4-hydroxy-1,3-benzenedimethanol sulfate, is a relatively selective beta-2-adrenergic bronchodilator used for the relief of bronchospasm. The bioavailability of two 4-mg tablet formulations, differing in their inactive excipients, and a syrup formulation, was evaluated. The three dosage forms were orally administered to 12 normal male volunteers in a randomized three-way crossover study. Plasma samples were collected at frequent time points through 12 h and analyzed for albuterol content by a specific GC–MS method. The drug was rapidly absorbed from all three formulations. Maximum drug concentrations were comparable for the three formulations and were obtained between 1.8–2.0 h. The areas under the plasma concentration–time curves were 68–78 h · ng/mL. The drug elimination phase half-live (t1/2β) ranged from 4.8 to 5.5 h. Analysis of the data showed that the bioavailability of albuterol from a tablet formulation is equivalent to that from a solution.