The present study reports the production and characterization of PEG-coated silica nanoparticles (SiNP-PEG) containing insulin for oral administration. High (PEG 20,000) and low (PEG 6000) PEG molecular weights were used in the preparations. SiNP were produced by sol-gel technology followed by PEG adsorption and characterized for in vitro release by Franz diffusion cells. In vitro permeation profile was assessed using everted rat intestine. HPLC method has been validated for the determination of insulin released and permeated. Insulin secondary structure was performed by circular dichroism (CD). Uncoated SiNP allowed slower insulin release in comparison to SiNP-PEG. The coating with high molecular weight PEG did not significantly (p> 0.05) alter insulin release. The slow insulin release is attributed to the affinity of insulin for silanol groups at silica surface. Drug release followed second order kinetics for uncoated and SiNP-PEG at pH 2.0. On the other hand, at pH 6.8, the best fitting was first-order for SiNP-PEG, except for SiNP which showed a Boltzmann behavior. Comparing the values of half-live, SiNP-PEG 20,000 showed a faster diffusion followed by Si-PEG 6000 and SiNP. CD studies showed no conformational changes occurring after protein release from the nanoparticles under gastrointestinal simulated conditions.
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http://dx.doi.org/10.1016/j.ijpharm.2014.07.049 | DOI Listing |
Acta Physiol (Oxf)
February 2025
Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden.
Aim: Somatostatin from pancreatic δ-cells is a paracrine regulator of insulin and glucagon secretion, but the release kinetics and whether secretion is altered in diabetes is unclear. This study aimed to improve understanding of somatostatin secretion by developing a tool for real-time detection of somatostatin release from individual pancreatic islets.
Methods: Reporter cells responding to somatostatin with cytoplasmic Ca concentration ([Ca]) changes were generated by co-expressing somatostatin receptor SSTR2, the G-protein Gα15 and a fluorescent Ca sensor in HeLa cells.
Insulin degrading enzyme (IDE) is a dimeric 110 kDa M16A zinc metalloprotease that degrades amyloidogenic peptides diverse in shape and sequence, including insulin, amylin, and amyloid-β, to prevent toxic amyloid fibril formation. IDE has a hollow catalytic chamber formed by four homologous subdomains organized into two ∼55 kDa N- and C-domains (IDE-N and IDE-C, respectively), in which peptides bind, unfold, and are repositioned for proteolysis. IDE is known to transition between a closed state, poised for catalysis, and an open state, able to release cleavage products and bind new substrate.
View Article and Find Full Text PDFCurr Res Pharmacol Drug Discov
December 2024
Pregnancy Health Research Center, Zahedan University of Medical Sciences, Zahedan, Iran.
Background: Asprosin, a novel adipokine released under fasting conditions, may play a significant role in the pathophysiology of type 2 diabetes mellitus (T2DM). The objective of this study is to investigate the effects of metformin on serum asprosin levels and FBN1 gene expression in white adipose tissue in male rats.
Methods: Thirty-two male Wistar rats were randomly and equally divided into four groups (n = 8): 1.
Hum Exp Toxicol
January 2025
Department of Gynecology and Obstetrics, Fuyong People's Hospital, Shenzhen, China.
Gestational diabetes mellitus (GDM) is a metabolic disorder that arises during pregnancy and heightens the risk of placental dysplasia. Ginsenoside Re (Re) may stabilize insulin and glucagon to regulate glucose levels, which may improve diabetes-associated diseases. This study aims to investigate the mechanism of Re in high glucose (HG)-induced apoptosis of trophoblasts through endoplasmic reticulum stress (ERS)-related protein CHOP/GADD153.
View Article and Find Full Text PDFJ Clin Med
December 2024
Anesthesiology and Operative Intensive Care, Faculty of Medicine, University of Augsburg, 86156 Augsburg, Germany.
Mediastinal mass syndrome represents a major threat to respiratory and cardiovascular integrity, with difficult evidence-based risk stratification for interdisciplinary management. We conducted a narrative review concerning risk stratification and difficult airway management of patients presenting with a large mediastinal mass. This is supplemented by a case report illustrating our individual approach for a patient presenting with a subtotal tracheal stenosis due to a large cyst of the thyroid gland.
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