The objective of this study is to investigate if the systemic drug exposure of at least 25 μg and perhaps 50 μg salmeterol presented as inhalation powder in PE capsules and administered via HandiHaler® 2 does not exceed that of 50 μg Serevent® Diskus® and to investigate safety and tolerability of salmeterol presented as inhalation powder in PE capsules and administered via HandiHaler® 2