Clinical pharmacokinetic and pharmacodynamic evaluation of transdermal drug delivery systems of salbutamol sulfate

Transdermal drug delivery formulation containing 5 mg/patch of salbutamol sulfate (SS), providing an input rate of 100 mug/h of SS was formulated and subjected for pharmacokinetic and pharmacodynamic evaluation in moderately asthmatic patients (n = 6). A linear correlation was observed between cumulative amount of drug diffused in vitro and cumulative AUC(0-t) of serum concentration-time curve (R-2 = 0.99). A steady-state serum concentration of 2.87 +/- 0.1 ng/ml (per milligram dose) was attained after an initial lag period of 4.67 +/- 1.03 h. The elimination half-life, clearance rate and elimination rate constant was 3.35 +/- 1.07 h, 256.12 +/- 3.55 ml/min and 0.24 +/- 0.09 h(-1), respectively. The mean forced expiratory volume in one minute (FEV1) of the patients was 2.2 +/- 0.141 during steady state. The pharmacokinetic results correlated well with the FEV1 response of patients. (C) 2004 Elsevier B.V. All rights reserved.