Terbutaline, clinical studies

Ravishankar, H., Iyer-Chavan, I, Patil, P, Samel, A., and Renner, G. (2006), Clinical studies of terbutaline controlled-release formulation prepared using EUDRAMODE, Drug Deliv. Technol., 6, 50-56. 

Stereoselectivity in the pharmacodynamics of p2-agonists has been extensively studied at both the receptor and the end-clinical response levels [82-95]. Except for trimethoquinol, the bronchodilator action of all p2-agonists is predominantly due to the R enantiomer. Using excised tissues from various animals and humans, it has been shown that p2-adrenoceptor agonist activity resides mainly with the R or (R,R) isomers of racemic albuterol, terbutaline, formoterol, and clenbuterol (Table 5) [82-95]. 

In patients with reversible airway obstruction (81), the greatest bronchodi-latation was obtained when the pMDI containing terbutaline was actuated during a slow inhalation (25 to 30 L/min) and actuation is followed by a breath-hold lasting 10 s. A significant correlation between mean bronchodilator response for the different inhalation modes and pulmonary deposition of labeled Teflon particles obtained in the aforementioned studies was reported (77). Studies with other Pj-agonists inhaled via pMDI have given similar results (82) and confirmed the clinical relevance of flow dependency of pulmonary deposition for pMDIs. 

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