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Naito A, Kawamura I. Dynamic membrane interaction and amyloid fibril formation of glucagon, melittin and human calcitonin. Biophys Chem 2023; 298:107025. [PMID: 37127008 DOI: 10.1016/j.bpc.2023.107025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/20/2023] [Accepted: 04/21/2023] [Indexed: 05/03/2023]
Abstract
Glucagon is a 29-amino acid peptide hormone secreted by pancreatic α-cells and interacts with specific receptors located in various organs. Glucagon tends to form gel-like fibril aggregates that are cytotoxic. It is important to reveal the glucagon-membrane interaction to understand activity and cytotoxicity of glucagon and glucagon oligomers. In this review, first glucagon-membrane interactions are described as morphological changes in dimyristoylphosphatidylcholine (DMPC) bilayers containing glucagon in acidic and neutral conditions as compared to the case of melittin. Second, fibril formation by glucagon in acidic solution is discussed in light of morphological and structural changes. Third, kinetic analysis of glucagon fibril formation was performed using a two-step autocatalytic reaction mechanism, as investigated in the case of human calcitonin. The first step is a nuclear formation, and the second step is an autocatalytic fibril elongation. Forth, fibril formation of glucagon inside glucagon-DMPC bilayers in neutral solution under near physiological condition is described.
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Affiliation(s)
- Akira Naito
- Graduate School of Engineering, Yokohama National University, Yokohama 240-8501, Japan.
| | - Izuru Kawamura
- Graduate School of Engineering, Yokohama National University, Yokohama 240-8501, Japan
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Lu B, GhavamiNejad A, Liu JF, Li J, Mirzaie S, Giacca A, Wu XY. "Smart" Composite Microneedle Patch Stabilizes Glucagon and Prevents Nocturnal Hypoglycemia: Experimental Studies and Molecular Dynamics Simulation. ACS APPLIED MATERIALS & INTERFACES 2022; 14:20576-20590. [PMID: 35471922 DOI: 10.1021/acsami.1c24955] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Hypoglycemia is a major complication associated with insulin therapy in people with diabetes that could cause life-threatening conditions if untreated. Glucagon, a counter-acting hormone, is thus administered for rescue of severe hypoglycemia. However, due to the instability of glucagon, only limited medications are available for emergency use, which are unsuitable for patients with hypoglycemia unawareness or with the inability to self-administer, especially during sleep (namely, nocturnal hypoglycemia). To prevent unattended and extended hypoglycemia, we designed a "smart" composite microneedle (cMN) patch capable of stabilizing glucagon, sensing hypoglycemia, and delivering glucagon automatically on demand. In this design, native glucagon was encapsulated in glucose-responsive microgels containing a glucagon-stabilizing component rationally selected by molecular dynamics (MD) simulation. A cMN patch was then prepared by incorporating the glucagon microgels with poly(methyl vinyl ether-alt-maleic anhydride) (PMVE-MAH) and poly(ethylene glycol) (PEG) followed by thermal cross-linking. The rationally designed zwitterionic polymer-based microgels preserved the native structure of glucagon and prevented heat-induced fibrillation evidenced by RP-HPLC, circular dichroism, and transmission electron microscopy. MD simulations suggested that the polymeric microgels stabilized glucagon by inhibition of oligomer formation via peptide-polymer noncovalent interactions. The polymer formed multiple hydrogen bonds with the polar and charged amino acid residues of the glucagon molecule, shielding the peptide surface from aggregation. In vivo efficacy studies using streptozotocin-induced type 1 diabetic (T1D) rats demonstrated that the glucagon-loaded cMN patch could prevent hypoglycemia induced by insulin overdose during a 12 h period. The results suggest that this new glucagon "smart" patch may be a promising system for improving the quality of life of those suffering from nocturnal hypoglycemia and hypoglycemia unawareness.
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Affiliation(s)
- Brian Lu
- Advanced Pharmaceutics and Drug Delivery Laboratory, Leslie L. Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - Amin GhavamiNejad
- Advanced Pharmaceutics and Drug Delivery Laboratory, Leslie L. Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - Jackie Fule Liu
- Advanced Pharmaceutics and Drug Delivery Laboratory, Leslie L. Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - Jason Li
- Advanced Pharmaceutics and Drug Delivery Laboratory, Leslie L. Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - Sako Mirzaie
- Advanced Pharmaceutics and Drug Delivery Laboratory, Leslie L. Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
| | - Adria Giacca
- Departments of Physiology and Medicine, Institute and Medical Science and Banting and Best Diabetes Centre, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Xiao Yu Wu
- Advanced Pharmaceutics and Drug Delivery Laboratory, Leslie L. Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada
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Amyloidogenicity of peptides targeting diabetes and obesity. Colloids Surf B Biointerfaces 2021; 209:112157. [PMID: 34715595 DOI: 10.1016/j.colsurfb.2021.112157] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 09/20/2021] [Accepted: 10/09/2021] [Indexed: 12/15/2022]
Abstract
Since the discovery of insulin, a century ago, the repertoire of therapeutic polypeptides targeting diabetes - and now also obesity - have increased substantially. The focus on quality has shifted from impure and unstable preparations of animal insulin to highly pure, homologous recombinant insulin, along with other peptide-based hormones and analogs such as amylin analogs (pramlintide, davalintide, cagrilintide), glucagon and glucagon-like peptide-1 receptor agonists (GLP-1, liraglutide, exenatide, semaglutide). Proper formulation, storage, manipulation and usage by professionals and patients are required in order to avoid agglomeration into high molecular weight products (HMWP), either amorphous or amyloid, which could result in potential loss of biological activity and short- or long-term immune reaction and silent inactivation. In this narrative review, we present perspective of the aggregation of therapeutic polypeptides used in diabetes and other metabolic diseases, covering the nature and mechanisms, analytical techniques, physical and chemical stability, strategies aimed to hamper the formation of HMWP, and perspectives on future biopharmaceutical developments.
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Naito A. Fibril Formation by Glucagon in Solution and in Membrane Environments. Mol Pharmacol 2020. [DOI: 10.5772/intechopen.91681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Glucagon is a 29-amino acid peptide hormone secreted by pancreatic α-cells and interacts with specific receptors located in various organs. Glucagon tends to form gel-like fibril aggregates that are cytotoxic because they activate apoptotic signaling pathways. First, fibril formation by glucagon in acidic solution is discussed in light of morphological and structural changes during elapsed time. Second, we provide kinetic analyses using a two-step autocatalytic reaction mechanism; the first step is a homogeneous nuclear formation process, and the second step is an autocatalytic heterogeneous fibril elongation process. Third, the processes of fibril formation by glucagon in a membrane environment are discussed based on the structural changes in the fibrils. In the presence of bicelles in acidic solution, glucagon interacts with the bicelles and forms fibril intermediates on the bicelle surface and grows into elongated fibrils. Glucagon-dimyristoylphosphatidylcholine (DMPC) bilayers in neutral solution mimic the environment for fibril formation by glucagon under near-physiological condition. Under these conditions, glucagon forms fibril intermediates that grow into elongated fibrils inside the lipid bilayer. Many days after preparing the glucagon-DMPC bilayer sample, the fibrils form networks inside and outside the bilayer. Furthermore, fibril intermediates strongly interact with lipid bilayers to form small particles.
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Haya K, Makino Y, Kikuchi-Kinoshita A, Kawamura I, Naito A. 31P and 13C solid-state NMR analysis of morphological changes of phospholipid bilayers containing glucagon during fibril formation of glucagon under neutral condition. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183290. [DOI: 10.1016/j.bbamem.2020.183290] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 02/25/2020] [Accepted: 03/23/2020] [Indexed: 02/07/2023]
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Schiavone NM, Pirrone GF, Guetschow ED, Mangion I, Makarov AA. Combination of circular dichroism spectroscopy and size-exclusion chromatography coupled with HDX-MS for studying global conformational structures of peptides in solution. Talanta 2019; 194:177-182. [DOI: 10.1016/j.talanta.2018.09.077] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 09/19/2018] [Accepted: 09/20/2018] [Indexed: 01/10/2023]
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Yamane I, Momose A, Fujita H, Yoshimoto E, Kikuchi-Kinoshita A, Kawamura I, Naito A. Fibrillation mechanism of glucagon in the presence of phospholipid bilayers as revealed by 13C solid-state NMR spectroscopy. Chem Phys Lipids 2019; 219:36-44. [DOI: 10.1016/j.chemphyslip.2019.01.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 01/23/2019] [Accepted: 01/23/2019] [Indexed: 12/23/2022]
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Haymond MW, Redondo MJ, McKay S, Cummins MJ, Newswanger B, Kinzell J, Prestrelski S. Nonaqueous, Mini-Dose Glucagon for Treatment of Mild Hypoglycemia in Adults With Type 1 Diabetes: A Dose-Seeking Study. Diabetes Care 2016; 39:465-8. [PMID: 26861921 PMCID: PMC4764034 DOI: 10.2337/dc15-2124] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 11/23/2015] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To evaluate mini-dose glucagon in adults with type 1 diabetes using a stable, liquid, ready-to-use preparation. RESEARCH DESIGN AND METHODS Twelve adults with type 1 diabetes receiving treatment with insulin pumps received subcutaneous doses of 75, 150, and 300 μg of nonaqueous glucagon. Plasma glucose, glucagon, and insulin concentrations were measured. At 180 min, subjects received insulin followed in ~60 min by a second identical dose of glucagon. RESULTS Mean (±SE) fasting glucose concentrations (mg/dL) were 110 ± 7, 110 ± 10, and 109 ± 9 for the 75-, 150-, and 300-μg doses, respectively, increasing maximally at 60 min by 33, 64, and 95 mg/dL (all P < 0.001). The post-insulin administration glucose concentrations were 70 ± 2, 74 ± 5, and 70 ± 2 mg/dL, respectively, with maximal increases of 19, 24, and 43 mg/dL post-glucagon administration (P < 0.02) at 45-60 min. CONCLUSIONS Subcutaneous, nonaqueous, ready-to-use G-Pen Mini glucagon may provide an alternative to oral carbohydrates for the management of anticipated, impending, or mild hypoglycemia in adults with type 1 diabetes.
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Affiliation(s)
- Morey W Haymond
- Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX
| | - Maria J Redondo
- Division of Pediatric Endocrinology and Metabolism, Baylor College of Medicine, Houston, TX
| | - Siripoom McKay
- Division of Pediatric Endocrinology and Metabolism, Baylor College of Medicine, Houston, TX
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Moorthy BS, Ghomi HT, Lill MA, Topp EM. Structural transitions and interactions in the early stages of human glucagon amyloid fibrillation. Biophys J 2015; 108:937-948. [PMID: 25692598 DOI: 10.1016/j.bpj.2015.01.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 12/07/2014] [Accepted: 01/08/2015] [Indexed: 01/08/2023] Open
Abstract
A mechanistic understanding of the intermolecular interactions and structural changes during fibrillation is crucial for the design of safe and efficacious glucagon formulations. Amide hydrogen/deuterium exchange with mass spectrometric analysis was used to identify the interactions and amino acids involved in the initial stages of glucagon fibril formation at acidic pH. Kinetic measurements from intrinsic and thioflavin T fluorescence showed sigmoidal behavior. Secondary structural measurement of fibrillating glucagon using far-UV circular dichroism spectroscopy showed changes in structure from random coil → α-helix → β-sheet, with increase in α-helix content during the lag phase followed by increase in β-sheet content during the growth phase. Hydrogen/deuterium exchange with mass spectrometric analysis of fibrillating glucagon suggested that C-terminal residues 22-29 are involved in interactions during the lag phase, during which N-terminal residues 1-6 showed no changes. Molecular dynamics simulations of glucagon fragments showed C-terminal to C-terminal interactions with greater α-helix content for the 20-29 fragment, with hydrophobic and aromatic residues (Phe-22, Trp-25, Val-23, and Met-27) predominantly involved. Overall, the study shows that glucagon interactions during the early phase of fibrillation are mediated through C-terminal residues, which facilitate the formation of α-helix-rich oligomers, which further undergo structural rearrangement and elongation to form β-sheet-rich mature fibrils.
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Affiliation(s)
- Balakrishnan S Moorthy
- Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, Indiana
| | - Hamed Tabatabaei Ghomi
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
| | - Markus A Lill
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana
| | - Elizabeth M Topp
- Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, Indiana.
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Stability characterization and appearance of particulates in a lyophilized formulation of a model peptide hormone-human secretin. Int J Pharm 2015; 481:104-13. [DOI: 10.1016/j.ijpharm.2015.01.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 01/20/2015] [Accepted: 01/24/2015] [Indexed: 11/23/2022]
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Abstract
Type 1 diabetes is a common chronic disease of childhood and one of the most difficult conditions to manage. Advances in insulin formulations and insulin delivery devices have markedly improved the ability to achieve normal glucose homeostasis. However, hypoglycemia remains the primary limiting factor in achieving normoglycemia and is a frequent complication in children with acute gastroenteritis and/or poor oral intake. In situations of impaired carbohydrate intake or absorption, glucagon therapy is the only out-of-hospital treatment option available to families and caregivers. Glucagon is recommended for the treatment of severe hypoglycemia and rapidly increases blood glucose by increasing hepatic glucose production from glycogenolysis. Mini-dose glucagon is a widely utilized off-label treatment for managing mild or impending hypoglycemia and is administered as a small subcutaneous injection. It was initially described for use in children who were unable to tolerate or absorb oral carbohydrates but not in need of advanced medical care. Yet, mini-dose glucagon may be useful in any individual with relative insulin excess. The regimen aims to prevent severe hypoglycemic episodes and is safe, effective, and easily administered by patients and caregivers in the out-of-hospital setting. By empowering patients and their families, this important tool could help to alleviate the physical, psychosocial, and financial burden evolving from impending hypoglycemia.
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Affiliation(s)
- Stephanie T Chung
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda MD, USA
| | - Morey W Haymond
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
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Onoue S, Sato H, Ogawa K, Kawabata Y, Mizumoto T, Yuminoki K, Hashimoto N, Yamada S. Improved dissolution and pharmacokinetic behavior of cyclosporine A using high-energy amorphous solid dispersion approach. Int J Pharm 2010; 399:94-101. [DOI: 10.1016/j.ijpharm.2010.08.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 07/28/2010] [Accepted: 08/04/2010] [Indexed: 11/30/2022]
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Brown L, Edelman ER. Optimal control of blood glucose: the diabetic patient or the machine? Sci Transl Med 2010; 2:27ps18. [PMID: 20393187 DOI: 10.1126/scitranslmed.3001083] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In this issue of Science Translational Medicine, El-Khatib et al. describe a "closed-loop" bihormonal artificial pancreas, designed to avert episodes of low blood sugar in patients with insulin-dependent diabetes. We discuss the benefits and challenges of therapy directed at tight control of blood glucose and ask whether this and similar technological breakthroughs can address as yet unanswered questions in the biology of diabetes.
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Affiliation(s)
- Larry Brown
- Harvard MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, E25-438, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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Vonhoff S, Condliffe J, Schiffter H. Implementation of an FTIR calibration curve for fast and objective determination of changes in protein secondary structure during formulation development. J Pharm Biomed Anal 2010; 51:39-45. [DOI: 10.1016/j.jpba.2009.07.031] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 07/22/2009] [Accepted: 07/27/2009] [Indexed: 11/29/2022]
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Onoue S, Yamamoto K, Kawabata Y, Hirose M, Mizumoto T, Yamada S. Novel dry powder inhaler formulation of glucagon with addition of citric acid for enhanced pulmonary delivery. Int J Pharm 2009; 382:144-50. [PMID: 19703531 DOI: 10.1016/j.ijpharm.2009.08.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Revised: 08/19/2009] [Accepted: 08/20/2009] [Indexed: 10/20/2022]
Abstract
Glucagon, a gut hormone, is one of the key regulatory elements in glucose homeostasis, and is clinically used for treatment of hypoglycemia and premedication in peroral endoscopy. Dry powder inhaler (DPI) form of glucagon is believed to be a promising new dosage form, and the present study aimed to develop a novel glucagon-DPI using absorption enhancer for improved pharmacological effects. The cytotoxicity of citric and capric acids, the potential absorption enhancers, at 1 and 10 mM was assessed by monitoring extracellular LDH levels in rat alveolar L2 cells, and a concentration- and time-dependent release of LDH was observed in capric acid, but not in citric acid-treated cells. DPI form of glucagon containing citric acid was prepared with a jet mill, and laser diffraction and cascade impactor analyses of the newly developed glucagon-DPI suggested high dispersion and deposition in the respiratory organs with an emitted dose and fine particle fraction of 99.5 and 25%, respectively. Addition of citric acid in glucagon-DPI improved the dissolution behavior, and did not impair the solid-state stability of glucagon-DPI. Intratracheal administration of glucagon-DPI (50 microg-glucagon/kg body weight of rat) containing citric acid led to 2.9-fold more potent hyperglycemic effect in rats, as compared to inhaled glucagon-DPI without citric acid. Based on these physicochemical and pharmacological characterization, the dry powder inhaler of glucagon with addition of citric acid would be of use as an alternative to injection form.
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Affiliation(s)
- Satomi Onoue
- Department of Pharmacokinetics and Pharmacodynamics and Global Center of Excellence Program, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
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Iwasa S, Enomoto A, Onoue S, Nakai M, Yajima T, Fukushima T. Chromatographic Analysis of Conformationally Changed Insulin and Its Cytotoxic Effect on PC12 Cells. ACTA ACUST UNITED AC 2009. [DOI: 10.1248/jhs.55.825] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Sumiko Iwasa
- Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Toho University
| | - Akina Enomoto
- Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Toho University
| | - Satomi Onoue
- Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Toho University
- Department of Pharmacokinetics and Pharmacodynamics, School of Pharmaceutical Sciences, University of Shizuoka
| | - Minako Nakai
- Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Toho University
| | - Takehiko Yajima
- Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Toho University
| | - Takeshi Fukushima
- Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Toho University
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Matilainen L, Maunu SL, Pajander J, Auriola S, Jääskeläinen I, Larsen KL, Järvinen T, Jarho P. The stability and dissolution properties of solid glucagon/gamma-cyclodextrin powder. Eur J Pharm Sci 2008; 36:412-20. [PMID: 19059479 DOI: 10.1016/j.ejps.2008.11.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 10/19/2008] [Accepted: 11/08/2008] [Indexed: 11/28/2022]
Abstract
In the present study, the solid-state stability and the dissolution of glucagon/gamma-cyclodextrin and glucagon/lactose powders were evaluated. Freeze-dried powders were stored at an increased temperature and/or humidity for up to 39 weeks. Pre-weighed samples were withdrawn at pre-determined intervals and analyzed with HPLC-UV (HPLC=high performance liquid chromatography, UV=ultraviolet), HPLC-ESI-MS (ESI-MS=electrospray ionization mass spectrometry), SEC (size-exclusion chromatography), turbidity measurements and solid-state FTIR (Fourier Transform Infrared Spectroscopy). Dissolution of glucagon was evaluated at pH 2.5, 5.0 and 7.0. In addition, before storage, proton rotating-frame relaxation experiments of solid glucagon/gamma-cyclodextrin powder were conducted with CPMAS ((13)C cross-polarization magic-angle spinning) NMR (nuclear magnetic resonance) spectroscopy. In the solid state, glucagon was degraded via oxidation and aggregation and in the presence of lactose via the Maillard reaction. The solid-state stability of glucagon/gamma-cyclodextrin powder was better than that of glucagon/lactose powder. In addition, gamma-cyclodextrin improved the dissolution of glucagon at pH 5.0 and 7.0 and delayed the aggregation of glucagon after its dissolution at pH 2.5, 5.0 and 7.0. There was no marked difference between the proton rotating-frame relaxation times of pure glucagon and gamma-cyclodextrin, and thus, the presence of inclusion complexes in the solid state could not be ascertained by CPMAS NMR. In conclusion, when compared to glucagon/lactose powder, glucagon/gamma-cyclodextrin powder exhibited better solid-state stability and more favorable dissolution properties.
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Affiliation(s)
- Laura Matilainen
- Department of Pharmaceutical Chemistry, University of Kuopio, P.O.Box 1627, FIN-70211 Kuopio, Finland
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Matilainen L, Larsen KL, Wimmer R, Keski-Rahkonen P, Auriola S, Järvinen T, Jarho P. The effect of cyclodextrins on chemical and physical stability of glucagon and characterization of glucagon/gamma-CD inclusion complexes. J Pharm Sci 2008; 97:2720-9. [PMID: 17918736 DOI: 10.1002/jps.21209] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The purpose of the study was to evaluate the effect of cyclodextrin (CD) complexation on the chemical and physical stability of a polypeptide hormone glucagon and to study the interactions between glucagon and gamma-cyclodextrin molecules in inclusion complexes. The chemical stability of glucagon at pH 2.0 was studied with HPLC-UV and HPLC-MS/MS. The physical stability of glucagon at pH 2.5 was studied by measuring the turbidity (A(405 nm)) and viscosity (Ostwald capillary viscosimeter) of the samples. The structure of glucagon/gamma-CD complexes at pH 2.5 was studied with 2D-NMR. The presence of various CDs increased the chemical half-life of glucagon at pH 2.0 (37 degrees C, 0.01 M HCl, ionic strength 0.15) and prolonged the lag-time before aggregation at pH 2.5 (0.9% (w/v) NaCl in 3.2 mM HCl). The NMR studies showed that the side chains of all the aromatic amino acid residues (Phe6, Tyr10, Tyr13, Phe22, Trp25) and leucines (Leu14 and Leu26) of glucagon interacted with the cavities of the gamma-CD molecules. The present study shows that glucagon forms inclusion complexes with cyclodextrins in acidic solution, resulting in an improvement in its chemical and physical stability.
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Affiliation(s)
- Laura Matilainen
- Department of Pharmaceutical Chemistry, University of Kuopio, PO Box 1627, FIN-70211 Kuopio, Finland.
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Hoppe CC, Nguyen LT, Kirsch LE, Wiencek JM. Characterization of seed nuclei in glucagon aggregation using light scattering methods and field-flow fractionation. J Biol Eng 2008; 2:10. [PMID: 18613970 PMCID: PMC2483260 DOI: 10.1186/1754-1611-2-10] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Accepted: 07/09/2008] [Indexed: 11/10/2022] Open
Abstract
Background Glucagon is a peptide hormone with many uses as a therapeutic agent, including the emergency treatment of hypoglycemia. Physical instability of glucagon in solution leads to problems with the manufacture, formulation, and delivery of this pharmaceutical product. Glucagon has been shown to aggregate and form fibrils and gels in vitro. Small oligomeric precursors serve to initiate and nucleate the aggregation process. In this study, these initial aggregates, or seed nuclei, are characterized in bulk solution using light scattering methods and field-flow fractionation. Results High molecular weight aggregates of glucagon were detected in otherwise monomeric solutions using light scattering techniques. These aggregates were detected upon initial mixing of glucagon powder in dilute HCl and NaOH. In the pharmaceutically relevant case of acidic glucagon, the removal of aggregates by filtration significantly slowed the aggregation process. Field-flow fractionation was used to separate aggregates from monomeric glucagon and determine relative mass. The molar mass of the large aggregates was shown to grow appreciably over time as the glucagon solutions gelled. Conclusion The results of this study indicate that initial glucagon solutions are predominantly monomeric, but contain small quantities of large aggregates. These results suggest that the initial aggregates are seed nuclei, or intermediates which catalyze the aggregation process, even at low concentrations.
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Affiliation(s)
- Cindy C Hoppe
- Department of Chemical Engineering, University of South Florida, Tampa, FL, 33520, USA.
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Onoue S, Hashimoto N, Yamada S. Dry powder inhalation systems for pulmonary delivery of therapeutic peptides and proteins. Expert Opin Ther Pat 2008. [DOI: 10.1517/13543776.18.4.429] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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