A Review: The Prospect of Inhaled Insulin Therapy via Vibrating Mesh Technology to Treat Diabetes

Different Carriers for Use in Dry Powder Inhalers: Characteristics of Their Particles

In contemporary times, there has been a rise in the utilization of dry powder inhalers (DPIs) in the management of pulmonary and systemic diseases. These devices underwent a swift advancement in terms of both the equipment utilized and the formulation process. In this review, the carrier physicochemical characteristics that influence DPI performance are discussed, focusing its shape, morphology, size distribution, texture, aerodynamic diameter, density, moisture, adhesive and detachment forces between particles, fine carrier particles, and dry powder aerosolization. To promote the deposition of the active principal ingredient deep within the pulmonary system, advancements have been made in enhancing these factors and surface properties through the application of novel technologies that encompass particle engineering. So far, the most used carrier is lactose showing some advantages and disadvantages, but other substances and systems are being studied with the intention of replacing it. The final objective of this review is to analyze the physicochemical and mechanical characteristics of the different carriers or new delivery systems used in DPI formulations, whether already on the market or still under investigation. [Figure: see text].

Recent advances in transdermal insulin delivery technology: A review

Transdermal drug delivery refers to the administration of drugs through the skin, after which the drugs can directly act on or circulate through the body to the target organs or cells and avoid the first-pass metabolism in the liver and kidneys experienced by oral drugs, reducing the risk of drug poisoning. From the initial singular approach to transdermal drug delivery, there has been a shift toward combining multiple methods to enhance drug permeation efficiency and address the limitations of individual approaches. Technological advancements have also improved the accuracy of drug delivery. Optimizing insulin itself also enables its long-term release via needle-free injectors. In this review, the diverse transdermal delivery methods employed in insulin therapy and their respective advantages and limitations are discussed. By considering factors such as the principles of transdermal penetration, drug delivery efficiency, research progress, synergistic innovations among different methods, patient compliance, skin damage, and posttreatment skin recovery, a comprehensive evaluation is presented, along with prospects for potential novel combinatorial approaches. Furthermore, as insulin is a macromolecular drug, insights gained from its transdermal delivery may also serve as a valuable reference for the use of other macromolecular drugs for treatment.

Elucidating the Degradation Pathways of Human Insulin in the Solid State

While there have been significant advances in the development of peptide oral dosage forms in recent years, highlighted by the clinical and commercial success of approved peptides such as Rybelsus®, there remain several barriers in the way of broad range applicability of this approach to peptide delivery. One such barrier includes the poor physical and chemical stability inherent to their structures, which persists in the solid state although degradation typically occurs at different rates and via different pathways in comparison to the solution state. Using insulin as a model peptide, this work sought to contribute to the development of analytical techniques for investigating common insulin degradation pathways. Chemically denatured, deamidated and aggregated samples were prepared and used to benchmark circular dichroism spectroscopy, reverse phase HPLC and size exclusion chromatography methods for the investigation of unfolding, chemical modifications and covalent aggregation of the insulin molecule respectively. Solid state degraded samples were prepared by heating insulin powder at 60 °C and 75% relative humidity for 1, 3, 5 and 7 d, and the degradation profiles of the samples were evaluated and compared with those observed in solution. While no unfolding was observed to occur, significant deamidation and covalent aggregation were detected. Reductive disulfide bond cleavage using dithiothreitol allowed for separation of the insulin A- and B-chains, offering a facile yet novel means of assessing the mechanisms of deamidation and covalent aggregation occurring in the solid state.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41664-024-00302-5.

Insulin Therapy for the Management of Diabetes Mellitus: A Narrative Review of Innovative Treatment Strategies

The discovery of insulin was presented to the international medical community on May 3, 1922. Since then, insulin has become one of the most effective pharmacological agents used to treat type 1 and type 2 diabetes mellitus. However, the initiation and intensification of insulin therapy is often delayed in people living with type 2 diabetes due to numerous challenges associated with daily subcutaneous administration. Reducing the frequency of injections, using insulin pens instead of syringes and vials, simplifying treatment regimens, or administering insulin through alternative routes may help improve adherence to and persistence with insulin therapy among people living with diabetes. As the world commemorates the centennial of the commercialization of insulin, the aims of this article are to provide an overview of insulin therapy and to summarize clinically significant findings from phase 3 clinical trials evaluating less frequent dosing of insulin and the non-injectable administration of insulin.

Lipid-based particle engineering via spray-drying for targeted delivery of antibiotics to the lung

Pulmonary delivery of antibiotics for the treatment of tuberculosis provides several benefits compared to conventional oral and parenteral administration. API-loaded particles delivered directly to alveolar macrophages, where Mycobacterium tuberculosis resides, can reduce the required dose and decrease the severe side effects of conventional treatment. In this work, lipid-microparticles loaded with rifampicin were engineered via spray-drying to be administered as a carrier-free dry powder for inhalation. Although, it is well-known that spray-drying of lipid-based excipients is strongly limited, a completely lipid-based formulation using diglycerol full ester of behenic acid was produced. The solid state of the lipid, providing high melting temperature, absence of polymorphism and monophasic crystallization, led to high yield of spray-dried particles (83%). Inhalable particles of mass median aerodynamic diameter of 2.36 µm, median geometric size of 2.05 µm, and negative surface (-50.03 mV) were engineered. Such attributes were defined for deep lung deposition and targeted delivery of antibiotics to alveolar macrophages. Superior aerodynamic performance as carrier-free DPI was associated to a high fine particle fraction of 79.5 %. No in vitro cytotoxic effects were found after exposing epithelial cell lines and alveolar macrophages. In vitro uptake of particles into alveolar macrophages indicated the efficiency of their targeted delivery. The use of highly processable and safe lipid-based excipients for particle engineering via spray-drying can extend the availability of materials for functionalized applications for pulmonary delivery.

Factors Affecting Performance of Insulin Pen Injector Technology: A Narrative Review

BACKGROUND

Insulin treatment is an essential hormone replacement therapy for the survival of people with type 1 diabetes and is often used for treatment in type 2 diabetes, particularly as the disease progresses. Advances in insulin therapy have been made since its discovery, including production of human insulin and development of insulin analogs with improved efficacy and safety profiles. The different types of available insulin formulations allow health care professionals to personalize treatment to an individual's needs. Generally, insulin requires parenteral administration via subcutaneous injection owing to very low oral bioavailability.

METHODS

This article reviews the human, technological, economical, and regulatory factors affecting the performance of insulin pens and the relationship between them. Opportunities and challenges that insulin pen injections may encounter in the future are also considered.

RESULTS

Insulin delivery devices, together with other factors, influence dose accuracy, convenience, and quality of life, contributing to easier medication administration with high efficacy and safety. For patients, ease of use, fast and accurate drug delivery, and painless injection are the most valuable features of an insulin injection device. For manufacturers, technological feasibility and economic viability also need to be considered when developing injection devices.

CONCLUSION

Insulin pen injectors are generally preferred over vial and syringe, although access may be limited in some health care systems. Insulin pen injectors can adapt to different insulin regimens and formulations and have the potential to acquire dosing data in real time.

Recent advances predict a bright future for nebulizers

PURPOSE OF REVIEW

With the improvement in device technology and delivery methods of inhaled medications, along with development of novel compounds and recognition of the importance of personalized approach in the management of chronic airway diseases, nebulizers have not only maintained their place in the treatment hierarchy of airway disease but have also proven a vital platform for the development of new classes of drugs.

RECENT FINDINGS

This short review explores recent advances in nebulized drug delivery in chronic obstructive pulmonary disease and other chronic airway diseases, emphasizing the progress in nebulizer technology, physiologic advantages of nebulized drug delivery and the high versatility of currently available and developing nebulizer-delivered pharmacotherapies.

SUMMARY

Versatility and efficiency of nebulizers allows for a broad spectrum of existing and novel therapies to be clinically studied, facilitating the progress in phenotype-targeted pharmacotherapies in the management of chronic airway diseases.

Inhalable microparticles as drug delivery systems to the lungs in a dry powder formulations

Inhalation-administrated drugs remain an interesting possibility of addressing pulmonary diseases. Direct drug delivery to the lungs allows one to obtain high concentration in the site of action with limited systemic distribution, leading to a more effective therapy with reduced required doses and side effects. On the other hand, there are several difficulties in obtaining a formulation that would meet all the criteria related to physicochemical, aerodynamic and biological properties, which is the reason why only very few of the investigated systems can reach the clinical trial phase and proceed to everyday use as a result. Therefore, we focused on powders consisting of polysaccharides, lipids, proteins or natural and synthetic polymers in the form of microparticles that are delivered by inhalation to the lungs as drug carriers. We summarized the most common trends in research today to provide the best dry powders in the right fraction for inhalation that would be able to release the drug before being removed by natural mechanisms. This review article addresses the most common manufacturing methods with novel modifications, pros and cons of different materials, drug loading capacities with release profiles, and biological properties such as cytocompatibility, bactericidal or anticancer properties.

Production of Inhalable Ultra-Small Particles for Delivery of Anti-Inflammation Medicine via a Table-Top Microdevice

A table-top microdevice was introduced in this work to produce ultrasmall particles for drug delivery via inhalation. The design and operation are similar to that of spray-drying equipment used in industry, but the device itself is much smaller and more portable in size, simpler to operate and more economical. More importantly, the device enables more accurate control over particle size. Using Flavopiridol, an anti-inflammation medication, formulations have been developed to produce inhalable particles for pulmonary delivery. A solution containing the desired components forms droplets by passing through an array of micro-apertures that vibrate via a piezo-electrical driver. High-purity nitrogen gas was introduced and flew through the designed path, which included the funnel collection and cyclone chamber, and finally was pumped away. The gas carried and dried the micronized liquid droplets along the pathway, leading to the precipitation of dry solid microparticles. The formation of the cyclone was essential to assure the sufficient travel path length of the liquid droplets to allow drying. Synthesis parameters were optimized to produce microparticles, whose morphology, size, physio-chemical properties, and release profiles met the criteria for inhalation. Bioactivity assays have revealed a high degree of anti-inflammation. The above-mentioned approach enabled the production of inhalable particles in research laboratories in general, using the simple table-top microdevice. The microparticles enable the inhalable delivery of anti-inflammation medicine to the lungs, thus providing treatment for diseases such as pulmonary fibrosis and COVID-19.

Aerosol therapy during mechanical ventilation in intensive care units: A questionnaire-based survey of 2203 ICU medical staff in China

Background

To describe the current status of aerosol therapy during mechanical ventilation (MV) and the practice, knowledge, and beliefs about aerosol therapy in physicians working in the intensive care unit (ICU) in China.

Methods

A physician self-administered questionnaire-based cross-sectional survey was carried out from January 2019 to July 2019. An electronic questionnaire was designed, and physicians who worked regularly in ICUs across several hospitals were contacted through WeChat. Answers to all questions and the general characteristics of physicians who answered the questionnaire were collected and analyzed.

Results

A total of 2203 medical staff who regularly worked in the ICUs completed this questionnaire (9.0% missing data); 87.7% of the participants were doctors. Most respondents claimed that they often administered aerosolization therapy. Ultrasonic atomizer (50.7%) and jet nebulizer (48.6%) were the most commonly used atomization devices. Bronchodilators (65.8%) and steroids (66.3%) were the most frequently aerosolized drugs during MV. During nebulization, ventilator settings were never changed by 32.7% of respondents. Only 49.1% of respondents knew the appropriate place for a nebulizer. Further, 62.7% of respondents using heated humidifiers reported turning them off during nebulization. Specific knowledge about droplet size and nebulization yield was poor. Respondents from tertiary hospitals and those with higher technical title or work experience tended to have better accuracy than those from primary hospitals or with lower technical titles (P < 0.050).

Conclusions

Aerosol therapy was commonly used during MV, and the most frequent drugs were bronchodilators and steroids. Scientific knowledge about the optimal implementation of aerosol therapy during MV seemed deficient.

Future directions in insulin therapy

Insulin therapy has a long history at the cutting edge of technological development through purification, extended-action, molecular chemistry, and devices, and in support technologies including self-measurement and patient education. But unmet needs remain large. Today's therapy cannot deliver minute-to-minute control of glucose levels, and cannot imitate the reflex/incretin driven physiological insulin delivery at mealtimes. Further it depends on a raft of devices for administration several times a day, devices liked for their functionality, but disliked as an intrusive reminder of the condition, several times a day. Approaches to overcoming these barriers include closed-loop systems and further modification of insulin formulations, but are limited by fundamental underlying difficulties. While clinical studies of oral insulin are in progress, the barriers to success look daunting. Development of small-molecule approaches (insulin-mimetic tablets) appears to have stalled, while concepts for glucose-responsive insulin as yet fail to deliver the necessary insulin-to-glucose gradient. Gene therapy, feasible in animals in preliminary studies, is not capable of providing feedback control. Transplantation of cultured islets and islet B-cells from stem cells thus looks to the be the best long-term prospect for insulin delivery in terms of overcoming the above barriers, but is a true biotechnological tour-de-force which will take time to mature.