Relative biologic availability and pharmacokinetics of albuterol preparations in healthy Chinese

The authors' goal was to study the biologic availability and pharmacokinetics of two different formulations of controlled-release (CR) tablets of albuterol. A two-way, cross-over biologic availability study was performed with 20 healthy male volunteers to evaluate the relative biologic availability of two CR tablets of albuterol versus two different formulations of immediate-release (IR) albuterol tablets. Albuterol concentrations in plasma were measured using an HPLC procedure. Each patient subject received a 4.8-mg CR tablet every 12 hours for 6 days and a 4.8-mg IR tablet every 8 hours for 6 days. Tests of single doses and steady state were assayed for CR and IR albuterol tablets. The mean Cmax and tmax for two CR tablets given after a single dose were 7.3+/-1.5, 7.9+/-1.4 microg x L(-1) and 4.6+/-0.8, 4.8+/-0.5 hours, respectively. The Cmax and tmax for two IR tablets given after a single dose were 12.5-/+1.3, 15.3 +/-2.3 microg x L(-1) and 1.3+/-0.4, 1.6+/-0.4 hours, respectively. The relative biologic availability of two CR albuterol tablets were 106.0+/-6.2% and 109.8+/-9.0%, respectively. Administration of CR albuterol twice a day provides an alternative to administration of IR albuterol three or four times a day.