1. Council GM, Commission GBM (2014) British pharmacopoeia. General Medical Council, London
2. Wilson CO, Beale JM, Block JH (2011) Wilson and Gisvold’s textbook of organic medicinal and pharmaceutical chemistry, 12th edn. Lippincott Williams & Wilkins, Philadelphia
3. Fozard JR, Buescher H (2001) Comparison of the anti-bronchoconstrictor activities of inhaled formoterol, its (R, R)- and (S, S)-enantiomers and salmeterol in the rhesus monkey. Pulm Pharm Ther 14:289–295
4. LaForce C, Feldman G, Spangenthal S, Eckert JH, Henley M, Patalano F, D’andrea P (2016) Efficacy and safety of twice-daily glycopyrrolate in patients with stable, symptomatic COPD with moderate-to-severe airflow limitation: the GEM1 study. Int J Chronic Obstr Pulm Dis 11:1233–1243
5. Martinez FJ, Klaus FR, Ferguson GT (2017) Efficacy and safety of glycopyrrolate/formoterol metered dose inhaler formulated using co-suspension delivery technology in patients with COPD. Chest 151:340–357