Zein-based nanocarriers for the oral delivery of insulin. In vivo evaluation in Caenorhabditis elegans

Oral nanotherapeutic formulation of insulin with reduced episodes of hypoglycaemia

Injectable insulin is an extensively used medication with potential life-threatening hypoglycaemic events. Here we report on insulin-conjugated silver sulfide quantum dots coated with a chitosan/glucose polymer to produce a responsive oral insulin nanoformulation. This formulation is pH responsive, is insoluble in acidic environments and shows increased absorption in human duodenum explants and Caenorhabditis elegans at neutral pH. The formulation is sensitive to glucosidase enzymes to trigger insulin release. It is found that the formulation distributes to the liver in mice and rats after oral administration and promotes a dose-dependent reduction in blood glucose without promoting hypoglycaemia or weight gain in diabetic rodents. Non-diabetic baboons also show a dose-dependent reduction in blood glucose. No biochemical or haematological toxicity or adverse events were observed in mice, rats and non-human primates. The formulation demonstrates the potential to orally control blood glucose without hypoglycaemic episodes.

Gliadin nanoparticles for oral administration of bioactives: Ex vivo and in vivo investigations

This study aims to provide a thorough characterization of Brij O2-stabilized gliadin nanoparticles to be used for the potential oral administration of various compounds. Different techniques were used in order to evaluate their physico-chemical features and then in vivo studies in rats were performed for the investigation of their biodistribution and gastrointestinal transit profiles. The results showed that the gliadin nanoparticles accumulated in the mucus layer of the bowel mucosa and evidenced their ability to move along the digestive systems of the animals. The incubation of the nanosystems with Caenorhabditis elegans, used as an additional in vivo model, confirmed the intake of the particles and evidenced their presence along the entire gastrointestinal tract of these nematodes. The gliadin nanoparticles influenced neither the egg-laying activity of the worms nor their metabolism of lipids up to 10 μg/mL of nanoformulation. The systems decreased the content of the age-related lipofuscin pigment in the nematodes in a dose-dependent manner, demonstrating a certain antioxidant activity. Lastly, dihydroethidium staining showed the absence of oxidative stress upon incubation of the worms together with the formulations, confirming their safe profile. This data paves the way for the future application of the proposed nanosystems regarding the oral delivery of various bioactives.

Nanomedical research and development in Spain: improving the treatment of diseases from the nanoscale

The new and unique possibilities that nanomaterials offer have greatly impacted biomedicine, from the treatment and diagnosis of diseases, to the specific and optimized delivery of therapeutic agents. Technological advances in the synthesis, characterization, standardization, and therapeutic performance of nanoparticles have enabled the approval of several nanomedicines and novel applications. Discoveries continue to rise exponentially in all disease areas, from cancer to neurodegenerative diseases. In Spain, there is a substantial net of researchers involved in the development of nanodiagnostics and nanomedicines. In this review, we summarize the state of the art of nanotechnology, focusing on nanoparticles, for the treatment of diseases in Spain (2017-2022), and give a perspective on the future trends and direction that nanomedicine research is taking.

Zein nanoparticles for drug delivery: Preparation methods and biological applications

Zein, a vegetable protein extracted from corn (Zea mays L.), forms a gastro-resistant and mucoadhesive polymer that is cheap and easy to obtain and facilitates the encapsulation of bioactives with hydrophilic, hydrophobic, and amphiphilic properties. The methods used for synthesizing these nanoparticles include antisolvent precipitation/nanoprecipitation, pH-driven, electrospraying, and solvent emulsification-evaporation methods. Each method has its advantages in the preparation of nanocarriers, nevertheless, all of them enable the production of zein nanoparticles that are stable and resistant to environmental factors, with different biological activities required in the cosmetic, food, and pharmaceutical industries. Therefore, zein nanoparticles are promising nanocarriers that can encapsulate various bioactives with anti-inflammatory, antioxidant, antimicrobial, anticancer, and antidiabetic properties. This article reviews the principal methods for obtaining zein nanoparticles containing bioactives, the advantages and characteristics of each method, as well as the main biological applications of nanotechnology-based formulations.

Zein Microparticles and Nanoparticles as Drug Delivery Systems

Zein is a natural, biocompatible, and biodegradable polymer widely used in the pharmaceutical, biomedical, and packaging fields because of its low water vapor permeability, antibacterial activity, and hydrophobicity. It is a vegetal protein extracted from renewable resources (it is the major storage protein from corn). There has been growing attention to producing zein-based drug delivery systems in the recent years. Being a hydrophobic biopolymer, it is used in the controlled and targeted delivery of active principles. This review examines the present-day landscape of zein-based microparticles and nanoparticles, focusing on the different techniques used to obtain particles, the optimization of process parameters, advantages, disadvantages, and final applications.

Zein-Based Nanoparticles as Oral Carriers for Insulin Delivery

Zein, the major storage protein from corn, has a GRAS (Generally Regarded as Safe) status and may be easily transformed into nanoparticles, offering significant payloads for protein materials without affecting their stability. In this work, the capability of bare zein nanoparticles (mucoadhesive) and nanoparticles coated with poly(ethylene glycol) (mucus-permeating) was evaluated as oral carriers of insulin (I-NP and I-NP-PEG, respectively). Both nanocarriers displayed sizes of around 270 nm, insulin payloads close to 80 µg/mg and did not induce cytotoxic effects in Caco-2 and HT29-MTX cell lines. In Caenorhabditis elegans, where insulin decreases fat storage, I-NP-PEG induced a higher reduction in the fat content than I-NP and slightly lower than the control (Orlistat). In diabetic rats, nanoparticles induced a potent hypoglycemic effect and achieved an oral bioavailability of 4.2% for I-NP and 10.2% for I-NP-PEG. This superior effect observed for I-NP-PEG would be related to their capability to diffuse through the mucus layer and reach the surface of enterocytes (where insulin would be released), whereas the mucoadhesive I-NP would remain trapped in the mucus, far away from the absorptive epithelium. In summary, PEG-coated zein nanoparticles may be an interesting device for the effective delivery of proteins through the oral route.

Efficacy and safety of 28-day treatment with oral insulin (ORMD-0801) in patients with type 2 diabetes: A randomized, placebo-controlled trial

AIM

To assess the safety and efficacy of oral insulin (ORMD-0801) in patients with type 2 diabetes (T2D).

MATERIALS AND METHODS

After a 2-week washout of other medications, adult metformin-treated patients with T2D were randomized to receive placebo or 16 or 24 mg ORMD-0801, once daily, at bedtime, for 28 days. The mean change from baseline weighted mean night-time glucose levels was determined from 2 nights of continuous glucose monitoring (CGM) recordings during the placebo run-in and last week of treatment.

RESULTS

In total, 188 patients (HbA1c: 7.82% ± 0.88% [placebo] and 8.08% ± 1.11% [pooled ORMD-0801 group]) were enrolled. In the placebo group, mean night-time CGM increased from baseline by 13.7 ± 26.1 mg/dL, whereas the increase was significantly smaller in the pooled ORMD-0801 group (1.7 ± 23.5 mg/dL, P = .0120). Glycaemic control variables (24-hour, fasting and daytime CGM glucose) also displayed smaller increases with ORMD-0801 versus placebo. Change from baseline HbA1c was -0.01% in the pooled ORMD-0801 group versus +0.20% in the placebo group (P = .0149). ORMD-0801 was well tolerated, with similar adverse event and hypoglycaemia rates as placebo.

CONCLUSIONS

In patients with T2D, bedtime ORMD-0801 curbed increases in night-time glycaemia, 24-hour glycaemia and HbA1c, without increasing the risk of hypoglycaemia or safety events compared with the control arm.