Pharmacokinetics and relative bioavailability of salbutamol metered-dose inhaler in healthy volunteers.
OBJECTIVE
To study the pharmacokinetics and relative bioavailability of salbutamol metered-dose inhaler (MDI) in healthy volunteers.


METHODS
An HPLC method for the determination of salbutamol in human plasma was improved. Ten healthy male Chinese volunteers were enrolled in a randomized crossover study. After the subjects inhaled or orally administered 1.2 mg salbutamol, fourteen blood samples were collected at predetermined time points. The concentrations of salbutamol in plasma were assessed with non-compartment model to obtain the pharmacokinetic parameters. The relative bioavailability of MDI versus water solution was calculated.


RESULTS
The HPLC assay was sensitive, specific, accurate, and precise. The pharmacokinetics of salbutamol MDI was described well with two-compartment model. The parameters for salbutamol inhaled and orally administered were as following: T(max) (0.22+/-0.07) and (1.8+/-0.6) h, C(max) (3.4+/-1.1) and (3.9+/-1.4) microg/L, T(1/2) (4.5+/-1.5) and (4.6+/-1.1) h, AUC0-20 min (0.9+/-0.3) and (0.16+/-0.10) microg x h x L(-1), respectively. There were significant differences in T(max) and AUC0-20 min between the two dosage forms. The AUC0-20 min (inhal) was 8 times as high as the AUC0-20 min (po). The relative bioavailability of salbutamol MDI was 57 %+/-24 % compared with oral solution.


CONCLUSIONS
The absorption process of salbutamol MDI in human was significantly different from that of oral solution.
Du
Xiao-Li
XL
Department of Pharmacy, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China. lily22cn@yahoo.com.cn
Zhu
Zhu
Z
Fu
Qiang
Q
Li
Da-Kui
DK
Xu
Wen-Bing
WB
D000280:Administration, Inhalation; D000284:Administration, Oral; D000328:Adult; D000420:Albuterol / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D019540:Area Under Curve; D001682:Biological Availability; D001993:Bronchodilator Agents / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D018592:Cross-Over Studies; D006801:Humans; D008297:Male; D036501:Metered Dose Inhalers
D001993:Bronchodilator Agents; D000420:Albuterol