Liraglutide, the second GLP-1 analog approved in 2009 in Europe and 2010 in USA under the trade name Victoza (Novo Nordisk). Liraglutide is a synthetic molecule produced using DNA recombinant technology. Compared to native GLP-1, it has an addition of a 16 carbon fatty-acid side-chain at Lys26 and an Arg34Lys substitution (Neumiller et al., 2010). After s.c. injection, only 1–2% of liraglutide circulates as free peptide in the plasma as the rest is noncovalently bound to albumin as ensured by the fatty acid side-chain (Zhang et al., 2012). This prolongs the half-life of liraglutide to 11–15 h approximately and hence administration once daily is needed.
Malm-Erjefalt M, Bjornsdottir I, Vanggaard J, Helleberg H, Larsen U, Oosterhuis B, van Lier JJ, Zdravkovic M, Olsen AK: Metabolism and excretion of the once-daily human glucagon-like peptide-1 analog liraglutide in healthy male subjects and its in vitro degradation by dipeptidyl peptidase IV and neutral endopeptidase. Drug Metab Dispos. 2010 Nov;38(11):1944-53. doi: 10.1124/dmd.110.034066. Epub 2010 Aug 13.