1. Hectogram-scale synthesis of [Aib8 , Arg34 ]-GLP-1 (7-37) by liquid-phase fragment condensation
Mengjia Zhao, Jinhua Zhang, Yuanzhen Dong, Yufeng He J Pept Sci . 2022 Sep 22;e3452. doi: 10.1002/psc.3452.
Based on small-scale synthesis (0.3 g), a 100-g scale-up synthesis of crude [Aib8, Arg34]-glucagon-like peptide-1 (GLP-1) (7-37) was completed. The crude [Aib8, Arg34]-GLP-1 (7-37) was purified using a dynamic axial compression column 200 (DAC-200). Approximately 61 g of [Aib8, Arg34]-GLP-1 (7-37) with a purity of >99% was obtained through one-step reverse-phase chromatography. The purification yield was approximately 92%. The yield from the total reaction was approximately 60%. In summary, we developed an economical and environmentally friendly route to the synthesis and purification of crude [Aib8, Arg34]-GLP-1 (7-37), laying a foundation for subsequent industrial production.
2. Developing GLP-1 Conjugated Self-Assembling Nanofibers Using Copper-Catalyzed Alkyne-Azide Cycloaddition and Evaluation of Their Biological Activity
Peter M Moyle, Aun Raza, Peter J Cabot, Seyed Ebrahim Alavi Bioconjug Chem . 2021 Apr 21;32(4):810-820. doi: 10.1021/acs.bioconjchem.1c00091.
Glucagon-like peptide-1 GLP-1 is a gut-derived peptide secreted from pancreatic β-cells that reduces blood glucose levels and body weight; however, native GLP-1 (GLP-1(7-36)-NH2and GLP-1(7-37)) have shortin vivocirculation half-lives (~2 min) due to proteolytic degradation and rapid renal clearance due to its low molecular weight (MW; 3297.7 Da). This study aimed to improve the proteolytic stability and delivery properties of glucagon-like peptide-1 (GLP-1) through modifications that form nanostructures. For this purpose, N- (NtG) and C-terminal (CtG), and Lys26 side chain (K26G) alkyne-modified GLP-1 analogues were conjugated to an azide-modified lipidic peptide (L) to giveN-L,C-L, andK-26-L, respectively; orCtGwas conjugated with a fibrilizing self-assembling peptide (SAP) (AEAEAKAK)3to yieldC-S, using copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC).N-Ldemonstrated the best serum stability (t1/2> 48 h) compared toK-26-L(44 h),C-L(20 h),C-S(27 h), and the parental GLP-1(7-36;A8G)-NH2(A8G) (19 h) peptides. Each conjugate demonstrated subnanomolar hGLP-1RA potency, and none demonstrated toxicity toward PC-3 cells at concentrations up to 1 μM. Each analogue was observed by transmission electron microscopy to form fibrils in solution.K-26-Ldemonstrated among the best human serum stability (t1/2= 44 h) and similar hGLP-1RA potency (EC5048 pM) toC-S. In conclusion, this study provided an alternative to lipid modification, i.e., fibrillizing peptides, that could improve pharmacokinetic parameters of GLP-1.
No information is available on the excretion of liraglutide int milk or it clinical use during breastfeeding. Because liraglutide is a large peptide molecule with a molecular weight of 3751 daltons, the amount in milk is likely to be very low and absorption is unlikely because it is probably destroyed in the infant's gastrointestinal tract. Until more data become available, liraglutide should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant.