title: Preparation, characterization, and application of biotinylated and biotin-PEGylated glucagon-like peptide-1 analogues for enhanced oral delivery.
abstract: Glucagon-like peptide-1 (GLP-1) (7-36) is a type of incretin hormone with unique antidiabetic potential. The introduction of orally active GLP-1 offers substantial benefits in the treatment of type 2 diabetes over conventional injection-based therapies. Because the intestinal absorption of GLP-1 is restricted by its natural characteristics, we developed a series of GLP-1 analogues via the site-specific conjugation of biotin-NHS and/or of biotin-poly(ethylene glycol)-NHS at Lys 26 and Lys 34 of GLP-1 (7-36), respectively, in order to improve oral delivery. The resultant GLP-1 analogues, Lys 26,34-DiBiotin-GLP-1 (DB-GLP-1) and Lys 26-Biotin-Lys 34-(Biotin-PEG)-GLP-1 (DBP-GLP-1), were prepared and studied in terms of their chemical, structural, and biological properties. DBP-GLP-1 demonstrated superior proteolytic stability against trypsin, intestinal fluid, and the major GLP-1 inactivation enzyme (dipeptidyl peptidase-IV (DPP-IV)) to native GLP-1 or DB-GLP-1 ( p < 0.001). The in vitro insulinotropic effects of DB-GLP-1 and DBP-GLP-1 showed potent biological activity in a dose-dependent manner, which resembled that of native GLP-1 in terms of stimulating insulin secretion in isolated rat islets of Langerhans. Intraperitoneal glucose tolerance tests (IPGTT) after the oral administration of GLP-1 analogues in diabetic db/db mice demonstrated that DB-GLP-1 and DBP-GLP-1 significantly reduced the AUC 0-180 min of glucose for 3 h by 14.9% and 24.5% compared to that of native GLP-1, respectively ( p < 0.01). In particular, DBP-GLP-1 concentration in plasma rapidly increased 30 min after oral administration in rats, presumably due to improved intestinal absorption. These findings revealed that site-specific biotinylated and biotin-PEGylated GLP-1 is absorbed by intestine and that it has biological activity in vivo. Therefore, we propose that this orally active bioconjugated GLP-1 might be considered as a potential oral antidiabetic agent for type 2 diabetes mellitus.
authors: Drug Targeting Laboratory, College of Pharmacy, SungKyunKwan University, 300 Chonchon-dong, Jangan-ku, Suwon City 440-746, Korea.
authors: Su Young
authors: SY
authors: Chae
authors: Cheng-Hao
authors: CH
authors: Jin
authors: Han Jong
authors: HJ
authors: Shin
authors: Yu Seok
authors: YS
authors: Youn
authors: Seulki
authors: S
authors: Lee
authors: Kang Choon
authors: KC
authors: Lee
mesh_terms: D000042:Absorption; D000284:Administration, Oral; D000818:Animals; D001665:Binding Sites; D001710:Biotin / Q000737:chemistry*; D019921:Biotinylation; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy / Q000378:metabolism; D004795:Enzyme Stability / Q000187:drug effects; D052216:Glucagon-Like Peptide 1 / Q000008:administration & dosage* / Q000097:blood / Q000737:chemistry* / Q000494:pharmacology; D007004:Hypoglycemic Agents / Q000008:administration & dosage* / Q000097:blood / Q000737:chemistry* / Q000494:pharmacology; D007274:Injections, Intraperitoneal; D007413:Intestinal Mucosa / Q000378:metabolism; D008239:Lysine / Q000378:metabolism; D051379:Mice; D010447:Peptide Hydrolases / Q000378:metabolism; D011092:Polyethylene Glycols / Q000737:chemistry*; D051381:Rats; D012680:Sensitivity and Specificity
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D011092:Polyethylene Glycols; D001710:Biotin; D052216:Glucagon-Like Peptide 1; D010447:Peptide Hydrolases; D008239:Lysine