An overview of oral insulin delivery strategies (OIDS)

Core-shell aerogel design for enhanced oral insulin delivery

Current protein-based therapies often rely on intravenous and subcutaneous injections leading to patient discomfort due to the need for frequent administration. Oral administration route presents a more patient-friendly alternative, but overcoming the challenge of low drug bioavailability remains paramount. This limitation is primarily attributed to protein degradation in the harsh gastric environment, enzymatic breakdown, and poor intestinal permeability. With their unique properties, such as high porosity and surface area, and easy scalability, aerogels offer a promising platform for oral delivery of therapeutic proteins. This study focused on the development and characterization of both conventional and core-shell aerogels derived from natural polysaccharides for the oral delivery of insulin, utilizing Humulin R® U-100 as the insulin source for the first time. Aerogels were produced via supercritical carbon dioxide (sc-CO2) drying of alginate gel beads. Scanning Electron Microscopy (SEM) images confirmed that the core-shell aerogels had higher uniformity in size and a more well-defined porous structure in comparison to conventional aerogels. Structural differences of two alginate sources were evaluated by Fourier Transform Infrared (FTIR) spectroscopy. A notable difference in encapsulation efficiencies was observed between conventional (12 %) and core-shell (53 %) aerogels, highlighting the superior carrier characteristics of the latter ones. In vitro insulin release profiles from the core-shell aerogels demonstrated their potential suitability for delivering regular/short-acting insulin therapeutics since only 30 % of insulin was released in Simulated Gastric Fluid (SGF) after 120 min, whereas 60 % of insulin was released in Simulated Intestinal Fluid (SIF) within the first hour followed by a sustained release stage.

An environment-responsive platform based on acid-resistant metal organic framework for efficient oral insulin delivery

Oral insulin delivery is considered a revolutionary alternative to daily subcutaneous injections in terms of compliance and convenience. However, significant challenges remain in terms of inactivation in gastrointestinal environment and limited permeation across the intestinal epithelium. Herein, we used acid-resistant metal-organic framework (PCN-222) to load insulin and modified the exterior with sodium dodecyl sulfate (SDS) to achieve efficient oral insulin delivery. The PCN-222 nanocarrier with ordered mesoporous cage structure and suitable pore size achieved a high insulin loading of 75 %. The SDS on the surface of nanocarrier reduces its hydrophilicity while reversibly altering cell morphology and increasing epithelial cell permeability, thereby promoting intestinal epithelial absorption. The constructed particle (I@P@S) was encapsulated in sodium alginate (SA) microspheres to protect it from gastric acid degradation and releases it upon entry into the intestinal tract. Through an uptake pathway dominated by clathrin-mediated endocytosis, the released I@P@S realized efficient intestinal permeability and controlled insulin release under physiological conditions due to the phosphate sensitivity of PCN-222, leading to an in vivo bioavailability of 12.9 %. This work provides a valuable reference for the design of oral insulin delivery systems.

Hydrophobic ion pairing: lipophilicity improvement of anionic macromolecules by divalent cation mediated complex formation

The aim of this study was to develop an alternative strategy to sufficiently increase the lipophilicity of anionic model macromolecules (MM) without the use of cationic counterions. Enoxaparin (ENO), insulin (INS) and poly-L-glutamic acid (PLG) were ion paired with anionic surfactants (sodium decanoate (DEC), sodium dodecyl sulfate (SDS), sodium stearate (SS) and sodium octadecyl sulfate (SOS)), mediated by divalent cations such as magnesium, calcium and zinc. Complexes were evaluated regarding their precipitation efficiency and logDn-butanol/water. SEDDS were developed, loaded with the complexes and characterized for their size and stability. Finally, payloads and logDSEDDS/release medium were determined. Divalent cation mediated ENO, INS and PLG complexes were successfully formed as underlined by high precipitation efficiencies above 90% in case of Zn2+-mediated complexes. Most pronounced increase in logDn-butanol/water was achieved for ENO-Zn2+-SOS (1.85), INS-Zn2+-SOS (0.80) and PLG-Zn2+-SS (0.48) providing suitable solubilities in commonly used SEDDS components. Developed SEDDS displayed droplet sizes below 200 nm without major changes after loading with MM complexes. Payloads up to 18.72 mg/ml could be achieved in developed SEDDS for ENO-Zn2+-SOS, and 2.44 mg/ml and 6.93 mg/ml for INS-Zn2+-SOS and PLG-Zn2+-SS, respectively. In general, highest lipophilicity enhancement and thus solubility in SEDDS was obtained with Zn2+-mediated complexes among the investigated cations and particularly with the highly negatively charged polysaccharide ENO. The formation of complexes between anionic MM and anionic surfactants mediated by divalent cations, substituting normally used cationic counterions exhibiting higher toxicity, offers a promising alternative to enhance their lipophilicity for oral drug delivery.

Preparation and evaluation of oral insulin nanocapsule delivery systems

Insulin therapy is essential for regulating blood sugar levels. Conventional subcutaneous injection is prone to psychological stress, local tissue damage and severe blood glucose fluctuations, and thus the development of oral insulin technology has become an alternative therapy. However, oral insulin faces challenges such as difficult absorption, poor adhesion, low bioavailability, and short duration of action, due to the large molecular weight, low permeability, and easily degradable by enzymes and gastric acids. In this study, oral insulin nanocapsule delivery systems (Orl-Ins-NPs) were developed by using polylactic acid-co-glycolic acid (PLGA) as the encapsulation material for insulin loading. After preparation, optimization and characterization, the mean size of Orl-Ins-NPs was 140.08 nm, the encapsulation efficiency of the system was 54.3 %, and the loading capacity of insulin was 2.2 %. In addition, cationic modification with chitosan/ polyethyleneimine promoted adhesion and permeation of the intestinal mucus layer, and surface coating with pH-responsive methyl methacrylate trimethylamine ethyl chloride copolymer achieved 100 % gastric protection. The results of rat blood glucose test showed that, subcutaneous injection of the control group reduced blood glucose concentrations within 1 h and returned to initial levels within 4 h, while Orl-Ins-NPs slowly reduced blood glucose concentration to 51.3 % of the initial level and maintains stability within 10 h. Orl-Ins-NPs exhibited good physicochemical stabilities, sustained release property, improved in vitro acid resistance, as well as long-term in vivo hypoglycemic effect. This system demonstrates its potential clinical application in oral insulin and other protein drugs delivery.

Heyndrickxia coagulans spore-based nanoparticle generator for improved oral insulin delivery and hypoglycemic therapy

Due to the two major physiological barriers restricted by mucus penetration and epithelia transport, oral insulin therapy using nano-delivery system remains challenging. Heyndrickxia coagulans spores can survive the harsh conditions of gastrointestinal tract (GIT), and penetrate in the mucus through germination to probiotics with their amphipathic proteinaceous coat shedding in the gut epithelium, which makes it possible to be functionalized with hydrophilic peptide/protein and form nanoparticles (NPs) in vivo. Inspired by the natural physiological properties of spores, novel deoxycholic acid-modified Heyndrickxia coagulans spores loaded with insulin (DA-Spore/Ins) as the generators of autonomous bio-based nanoparticles were designed to solve these absorption barriers to enhance oral insulin delivery. The DA-Spore/Ins delivery system achieved preferable drug protection and rapid mucus penetration through its germination in the intestinal microenvironment. Meanwhile, DA-Spore/Ins NPs could be spontaneously formed by the self-assembly of the disintegrated DA-covalently amphipathic protein coat and the hydrophilic protein/peptides drug. This can efficiently transport through the epithelial cells through the bile acid pathway. In vivo studies indicated that DA-Spore/Ins delivery system achieved an oral relative bioavailability of 15.1 % and superior hypoglycemic effect in type I diabetic rats characterized by good biocompatibility. These studies suggested that the intrinsic biological characteristics of Heyndrickxia coagulans spore-based nanogenerators rendered their promising application in oral insulin or other protein drug therapy.

Once-Weekly Insulin Icodec in Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Clinical Trials (ONWARDS Clinical Program)

BACKGROUND

One hundred years have passed since the discovery of insulin, which is one of the most relevant events of the 20th century. This period resulted in extraordinary progress in the development of novel molecules to improve glucose control, simplify the insulin regimen, and ameliorate the quality of life. In late March 2024, the first once-weekly basal analog Icodec was approved for diabetes mellitus, generating high expectations. Our aim was to systematically review and meta-analyze the efficacy and safety of Icodec compared to once-daily insulin analogs in type 1 (T1D) and type 2 diabetes (T2D).

METHODS

PubMed/MEDLINE, Cochrane Library, and ClinicalTrials.gov were searched for randomized clinical trials (RCTs). Studies were included for the synthesis according to the following prespecified inclusion criteria: uncontrolled T1D or T2D, age ≥ 18 years, insulin Icodec vs. active comparators (Degludec U100, Glargine U100, Glargine U300, and Detemir), phase 3, multicenter, double-blind or open-label RCTs, and a study duration ≥ 24 weeks.

RESULTS

The systematic review included 4347 patients with T1D and T2D inadequately controlled (2172 randomized to Icodec vs. 2175 randomized to once-daily basal analogs). Icodec, compared to once-daily basal analogs, slightly reduced the levels of glycated hemoglobin (HbA1c) with an estimated treatment difference (ETD) of -0.14% [95%CI -0.25; -0.03], p = 0.01, and I2 68%. Patients randomized to Icodec compared to those on once-daily basal analogs had a greater probability to achieve HbA1c < 7% without clinically relevant or severe hypoglycemic events in 12 weeks from randomization with an estimated risk ratio (ERR) of 1.17, [95%CI 1.01, 1.36], p = 0.03, and I2 66%. We did not find a difference in fasting glucose levels, time in range, and time above range between Icodec and comparators. Icodec, compared to once-daily basal analogs, resulted in a slight but statistically significant weight gain of 0.62 kg [95%CI 0.25; 0.99], p = 0.001, and I2 25%. The frequency of hypoglycemic events (ERR 1.16 [95%CI 0.95; 1.41]), adverse events (ERR 1.04 [95%CI 1.00; 1.08]), injection-site reactions (ERR 1.08 [95%CI 0.62; 1.90]), and the discontinuation of treatments were similar between the two groups. Icodec was found to work better when used in a basal-only than basal-bolus regimen with an ETD in HbA1c of -0.22%, a probability of achieving glucose control of +33%, a probability of achieving glucose control without clinically relevant or severe hypoglycemia of +28%, more time spent in target (+4.55%) and less time spent in hyperglycemia (-5.14%). The risk of clinically relevant or severe hypoglycemic events was significantly higher when background glinides and sulfonylureas were added to basal analogs (ERR 1.42 [95%CI 1.05; 1.93]).

CONCLUSION

Insulin Icodec is substantially non-inferior to once-daily insulin analogs in T2D, either insulin-naïve or insulin-treated. However, Icodec works slightly better than competitors when used in a basal-only rather than basal-bolus regimen. Weight gain and hypoglycemic risk are substantially low but not negligible. Patients' education, adequate lifestyle and pharmacological interventions, and appropriate therapy adjustments are essential to minimize risks. This systematic review is registered as PROSPERO CRD42024568680.

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.

Revolutionizing type 1 diabetes management: Exploring oral insulin and adjunctive treatments

Type 1 diabetes (T1D) is a chronic autoimmune condition that affects millions of people worldwide. Insulin pumps or injections are the standard treatment options for this condition. This article provides a comprehensive overview of the several type 1 diabetes treatment options, focusing on oral insulin. The article is divided into parts that include immune-focused treatments, antigen vaccination, cell-directed interventions, cytokine-directed interventions, and non-immunomodulatory adjuvant therapy. Under the section on non-immunomodulatory adjunctive treatment, the benefits and drawbacks of medications such as metformin, amylin, sodium-glucose cotransporter inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1 Ras), and verapamil are discussed. The article also discusses the advantages of oral insulin, including increased patient compliance and more dependable and regular blood sugar control. However, several variables, including the enzymatic and physical barriers of the digestive system, impair the administration of insulin via the mouth. Researchers have looked at a few ways to get over these challenges, such as changing the structure of the insulin molecule, improving absorption with the use of absorption enhancers or nanoparticles, and taking oral insulin together with other medications. Even with great advancements in the use of these treatment strategies, T1D still needs improvement in the therapeutic difficulties. Future studies in these areas should focus on creating tailored immunological treatments, looking into combination medications, and refining oral insulin formulations in an attempt to better control Type 1 Diabetes. The ultimate objective is to create accurate, customized strategies that will enhance glycemic management and the quality of life for individuals with the condition.

Oral targeted drug delivery to post-gastrointestinal sites

As an essential branch of targeted drug delivery, oral targeted delivery is attracting growing attention in recent years. In addition to site-specific delivery for the treatment of locoregional diseases in the gastrointestinal tract (GIT), oral targeted delivery to remote sites beyond the GIT emerges as a cutting-edge research topic. This review aims to provide an overview of the fundamental concepts and most recent advances in this field. Owing to the physiological barriers existing in the GIT, carrier systems should be transported across the enteric epithelia to target remote sites. Recently, pioneer investigations have validated the transport of intact micro- or nanocarriers across gastrointestinal barriers and subsequently to various distal organs and tissues. The microfold (M) cell pathway is the leading mechanism underlying the oral absorption of particulates, but the contribution of the transcellular and paracellular pathways should not be neglected either. In addition to well-acknowledged physicochemical and biological factors, the formation of a protein corona may also influence the biological fate of carrier systems. Although in an early stage of conceptualization, oral targeted delivery to remote diseases has demonstrated promising potential for the treatment of inflammation, tumors, and diseases inflicting the lymphatic and mononuclear phagocytosis systems.

Integration of polysaccharide electrospun nanofibers with microneedle arrays promotes wound regeneration: A review

Utilizing electrospun nanofibers and microneedle arrays in wound regeneration has been practiced for several years. Researchers have recently asserted that using multiple methods concurrently might enhance efficiency, despite the inherent strengths and weaknesses of each individual approach. The combination of microneedle arrays with electrospun nanofibers has the potential to create a drug delivery system and wound healing method that offer improved efficiency and accuracy in targeting. The use of microneedles with nanofibers allows for precise administration of pharmaceuticals due to the microneedles' capacity to pierce the skin and the nanofibers' role as a drug reservoir, resulting in a progressive release of drugs over a certain period of time. Electrospun nanofibers have the ability to imitate the extracellular matrix and provide a framework for cellular growth and tissue rejuvenation, while microneedle arrays show potential for enhancing tissue regeneration and enhancing the efficacy of wound healing. The integration of electrospun nanofibers with microneedle arrays may be customized to effectively tackle particular obstacles in the fields of wound healing and drug delivery. However, some issues must be addressed before this paradigm may be fully integrated into clinical settings, including but not limited to ensuring the safety and sterilization of these products for transdermal use, optimizing manufacturing methods and characterization of developed products, larger-scale production, optimizing storage conditions, and evaluating the inclusion of multiple therapeutic and antimicrobial agents to increase the synergistic effects in the wound healing process. This research examines the combination of microneedle arrays with electrospun nanofibers to enhance the delivery of drugs and promote wound healing. It explores various kinds of microneedle arrays, the materials and processes used, and current developments in their integration with electrospun nanofibers.

Genetic perspectives on childhood monogenic diabetes: Diagnosis, management, and future directions

Monogenic diabetes is caused by one or even more genetic variations, which may be uncommon yet have a significant influence and cause diabetes at an early age. Monogenic diabetes affects 1 to 5% of children, and early detection and gene-tically focused treatment of neonatal diabetes and maturity-onset diabetes of the young can significantly improve long-term health and well-being. The etiology of monogenic diabetes in childhood is primarily attributed to genetic variations affecting the regulatory genes responsible for beta-cell activity. In rare instances, mutations leading to severe insulin resistance can also result in the development of diabetes. Individuals diagnosed with specific types of monogenic diabetes, which are commonly found, can transition from insulin therapy to sulfonylureas, provided they maintain consistent regulation of their blood glucose levels. Scientists have successfully devised materials and methodologies to distinguish individuals with type 1 or 2 diabetes from those more prone to monogenic diabetes. Genetic screening with appropriate findings and interpretations is essential to establish a prognosis and to guide the choice of therapies and management of these interrelated ailments. This review aims to design a comprehensive literature summarizing genetic insights into monogenetic diabetes in children and adolescents as well as summarizing their diagnosis and mana-gement.

Exploring mesoporous silica nanoparticles as oral insulin carriers: In-silico and in vivo evaluation

The advancements in nanoscience have brought attention to the potential of utilizing nanoparticles as carriers for oral insulin administration. This study aims to investigate the effectiveness of synthesized polymeric mesoporous silica nanoparticles (MSN) as carriers for oral insulin and their interactions with insulin and IR through in-silico docking. Diabetic rats were treated with various MSN samples, including pure MSN, Amin-grafted MSN/PEG/Insulin (AMPI), Al-grafted MSN/PEG/Insulin (AlMPI), Zinc-grafted MSN/PEG/Insulin (ZNPI), and Co-grafted MSN/PEG/Insulin (CMPI). The nanocomposites were synthesized using a hybrid organic-inorganic method involving MSNs, graphene oxide, and insulin. Characterization of the nanocomposites was conducted using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). In vivo tests included the examination of blood glucose levels and histopathological parameters of the liver and pancreas in type 1 diabetic rats. The MSN family demonstrated a significant reduction in blood glucose levels compared to the diabetic control group (p < 0.001). The synthesized nanocomposites exhibited safety, non-toxicity, fast operation, self-repairing pancreas, cost-effectiveness, and high efficiency in the oral insulin delivery system. In the in-silico study, Zn-grafted MSN, Co-grafted MSN, and Al-grafted MSN were selected. Docking results revealed strong interactions between MSN compounds and insulin and IR, characterized by the formation of hydrogen bonds and high binding energy. Notably, Co-grafted MSN showed the highest docking scores of -308.171 kcal/mol and -337.608 kcal/mol to insulin and IR, respectively. These findings demonstrate the potential of polymeric MSN as effective carriers for oral insulin, offering promising prospects for diabetes treatment.

Comparison of virus-capsid mimicking biologic-shell based versus polymeric-shell nanoparticles for enhanced oral insulin delivery

Virus-capsid mimicking mucus-permeable nanoparticles are promising oral insulin carriers which surmount intestinal mucus barrier. However, the impact of different virus-capsid mimicking structure remains unexplored. In this study, utilizing biotin grafted chitosan as the main skeleton, virus-mimicking nanoparticles endowed with biologic-shell (streptavidin coverage) and polymeric-shell (hyaluronic acid/alginate coating) were designed with insulin as a model drug by self-assembly processes. It was demonstrated that biologic-shell mimicking nanoparticles exhibited a higher intestinal trans-mucus (>80%, 10 min) and transmucosal penetration efficiency (1.6-2.2-fold improvement) than polymeric-shell counterparts. Uptake mechanism studies revealed caveolae-mediated endocytosis was responsible for the absorption of biologic-shell mimicking nanoparticles whereas polymeric-shell mimicking nanoparticles were characterized by clathrin-mediated pathway with anticipated lysosomal insulin digestion. Further, in vivo hypoglycemic study indicated that the improved effect of regulating blood sugar levels was virus-capsid structure dependent out of which biologic-shell mimicking nanoparticles presented the best performance (5.1%). Although the findings of this study are encouraging, much more work is required to meet the standards of clinical translation. Taken together, we highlight the external structural dependence of virus-capsid mimicking nanoparticles on the muco-penetrating and uptake mechanism of enterocytes that in turn affecting their in vivo absorption, which should be pondered when engineering virus-mimicking nanoparticles for oral insulin delivery.

Affordable oral proinsulin bioencapsulated in plant cells regulates blood sugar levels similar to natural insulin

Diabetes Mellitus is a silent epidemic affecting >500 million, which claimed 6.7 million lives in 2021, a projected increase of >670% in <20 years old in the next two decades but insulin is unaffordable for the large majority of the globe. Therefore, we engineered proinsulin in plant cells to facilitate oral delivery. Stability of the proinsulin gene and expression in subsequent generations, after removal of the antibiotic-resistance gene, was confirmed using PCR, Southern and western blots. Proinsulin expression was high (up to 12 mg/g DW or 47.5% of total leaf protein), stable up to one year after storage of freeze-dried plant cells at ambient temperature and met FDA regulatory requirements of uniformity, moisture content and bioburden. GM1 receptor binding, required for uptake via gut epithelial cells was confirmed by pentameric assembly of CTB-Proinsulin. IP insulin injections (without C peptide) in STZ mice rapidly decreased blood glucose level leading to transient hypoglycemia, followed by hepatic glucose compensation. On the other hand, other than the 15-min lag period of oral proinsulin (transit time required to reach the gut), the kinetics of blood sugar regulation of oral CTB-Proinsulin in STZ mice was very similar to naturally secreted insulin in healthy mice (both contain C-peptide), without rapid decrease or hypoglycemia. Elimination of expensive fermentation, purification and cold storage/transportation should reduce cost and increase other health benefits of plant fibers. The recent approval of plant cell delivery of therapeutic proteins by FDA and approval of CTB-ACE2 for phase I/II human clinical studies augur well for advancing oral proinsulin to the clinic.

Oral delivery of biomacromolecules by overcoming biological barriers in the gastrointestinal tract: an update

INTRODUCTION

Biomacromolecules have proven to be an attractive choice for treating diseases due to their properties of strong specificity, high efficiency, and low toxicity. Besides greatly improving the patient's complaint, oral delivery of macromolecules also complies with hormone physiological secretion, which has become one of the most innovative fields of research in recent years.

AREAS COVERED

Oral delivery biological barriers for biomacromolecule, transport mechanisms, and various administration strategies were discussed in this review, including absorption enhancers, targeting nanoparticles, mucoadhesion nanoparticles, mucus penetration nanoparticles, and intelligent bionic drug delivery systems.

EXPERT OPINION

The oral delivery of biomacromolecules has important clinical implications; however, these are still facing the challenges of low bioavailability due to certain barriers. Various promising technologies have been developed to overcome the barriers and improve the therapeutic effect of oral biomacromolecules. By considering safety and efficacy comprehensively, the development of intelligent nanoparticles based on the GIT environment has demonstrated some promise in overcoming these barriers; however, a more comprehensive understanding of the oral fate of oral biomacromolecules is still required.

Bibliometric analysis and visualization of transdermal drug delivery research in the last decade: global research trends and hotspots

Background: Transdermal delivery has become a crucial field in pharmaceutical research. There has been a proliferation of innovative methods for transdermal drug delivery. In recent years, the number of publications regarding transdermal drug delivery has been rising rapidly. To investigate the current research trends and hotspots in transdermal drug delivery, a comprehensive bibliometric analysis was performed. Methods: An extensive literature review was conducted to gather information on transdermal drug delivery that had been published between 2003 and 2022. The articles were obtained from the Web of Science (WOS) and the National Center for Biotechnology Information (NCBI) databases. Subsequently, the collected data underwent analysis and visualization using a variety of software tools. This approach enables a deeper exploration of the hotspots and emerging trends within this particular research domain. Results: The results showed that the number of articles published on transdermal delivery has increased steadily over the years, with a total of 2,555 articles being analyzed. The most frequently cited articles were related to the optimization of drug delivery and the use of nanotechnology in transdermal drug delivery. The most active countries in the field of transdermal delivery research were the China, United States, and India. Furthermore, the hotspots over the past 2 decades were identified (e.g., drug therapy, drug delivery, and pharmaceutical preparations and drug design). The shift in research focus reflects an increasing emphasis on drug delivery and control release, rather than simply absorption and penetration, and suggests a growing interest in engineering approaches to transdermal drug delivery. Conclusion: This study provided a comprehensive overview of transdermal delivery research. The research indicated that transdermal delivery would be a rapidly evolving field with many opportunities for future research and development. Moreover, this bibliometric analysis will help researchers gain insights into transdermal drug delivery research's hotspots and trends accurately and quickly.

Self-assembled chitosan-insulin oral nanoparticles - A critical perspective review

Chitosan is an abundant natural cationic polysaccharide with excellent biodegradability, bioadhesion, and biocompatibility. Chitosan is extensively researched for various particulate oral insulin drug delivery systems. Oral insulin is economically efficient and more convenient than injections, with greater patient compliance. Electrostatic ionic interaction between cationic chitosan and anionic polymer or insulin leads to the formation of spontaneously self-assembled nanoparticles. This simple technique attracted many researchers as it can be carried out quickly in mild conditions without harmful solvents, such as surfactants or chemical cross-linkers that might degrade the insulin structure. The formulated chitosan nanoparticles help to protect the core insulin from enzymatic degradation in the digestive system and improve paracellular intestinal uptake from the enterocytes due to mucoadhesion and reversible tight junction opening. Moreover, functionalized chitosan nanoparticles create newer avenues for targeted and prolonged delivery. This review focuses on modified chitosan-insulin nanoparticles and their implications on oral insulin delivery. Dependent variables and their optimal concentration ranges used in self-assembly techniques for chitosan-insulin nanoparticular synthesis are summarized. This review provides a comprehensive guide to fine-tune the essential factors to formulate stable insulin-chitosan nanoparticles using mild ionic interactions.

Insulin-loaded nanoparticles based on acetylated cashew gum/chitosan complexes for oral administration and diabetes treatment

Insulin is one of the most important drugs in the clinical treatment of diabetes. There is growing interest in oral insulin administration as it mimics the physiological pathway and potentially reduces side effects associated with subcutaneous injection. In this study, a nanoparticulate system was developed using acetylated cashew gum (ACG) and chitosan by the polyelectrolyte complexation method, for oral administration of insulin. The nanoparticles were characterized by size, zeta potential and encapsulation efficiency (EE%). And they had a particle size of 460 ± 11.0 nm, PDI of 0.2 ± 0.021, zeta potential of 30.6 ± 0.48 mV, and an EE% of 52.5 %. Cytotoxicity assays were performed for HT-29 cell lines. It was observed that ACG and nanoparticles did not have a significant effect on cell viability, verifying their biocompatibility. Hypoglycemic effects of the formulation were analyzed in vivo, noting that the nanoparticles reduced blood glucose by 51.0 % of baseline levels after 12 h, not inducing signs of toxicity or death. Biochemical and hematological profiles were not clinically modified. Histological study indicated no signs of toxicity. Results showed that the nanostructured system presented itself as a potential vehicle for oral insulin release.

pH-sensitive O-carboxymethyl chitosan/sodium alginate nanohydrogel for enhanced oral delivery of insulin

Oral drug delivery is considered the most preferred mode of treatment because of its high patient compliance and minimal invasiveness. However, the oral delivery of protein drug has been a difficult problem which restricts its application due to the unstable and inefficient penetration of protein in the gastrointestinal tract. In this study, a novel OCMC/SA nanohydrogel was prepared by using of O-carboxymethyl chitosan (OCMC) and sodium alginate (SA) to solve the problem. The OCMC/SA had a typical nanostructure, which was helpful to increase the specific surface area and enhanced the bioavailability of the drugs. OCMC/SA had a high drug loading capacity and realized passive drug targeting function by responding to the different pH value of the microenvironment. It could have a certain protective effect on drugs in strong acid circumstances, while its structure got loosed and effectively released drugs in intestinal circumstances. OCMC/SA could release the drug for >12 h, and the released insulin could maintain high activity. OCMC/SA nanohydrogel showed promising results in type 1 diabetic rats, and its pharmacological bioavailability was 6.57 %. In conclusion, this study constructed a novel OCMC/SA nanohydrogel, which had a lot of exciting characteristics and provided a new strategy for oral drug delivery.

Recent progress and research trend of anti-cataract pharmacology therapy: A bibliometric analysis and literature review

Cataract is the leading cause of blindness worldwide. Cataract phacoemulsification combined with intraocular lens implantation causes great burden to global healthcare, especially for low- and middle-income countries. Such burden would be significantly relieved if cataracts can effectively be treated or delayed by non-surgical means. Excitingly, novel drugs have been developed to treat cataracts in recent decades. For example, oxysterols are found to be able to innovatively reverse lens clouding, novel nanotechnology-loaded drugs improve anti-cataract pharmacological effect, and traditional Chinese medicine demonstrates promising therapeutic effects against cataracts. In the present review, we performed bibliometric analysis to provide an overview perspective regarding the research status, hot topics, and academic trends in the field of anti-cataract pharmacology therapy. We further reviewed the curative effects and molecular mechanisms of anti-cataract drugs such as lanosterol, metformin, resveratrol and curcumin, and prospected the possibility of their clinical application in future.

Arabinoxylans-Based Oral Insulin Delivery System Targeting the Colon: Simulation in a Human Intestinal Microbial Ecosystem and Evaluation in Diabetic Rats

Arabinoxylans (AX) microcapsules loaded with insulin were prepared by enzymatic gelation of AX, using a triaxial electrospray method. The microcapsules presented a spherical shape, with an average size of 250 µm. The behavior of AX microcapsules was evaluated using a simulator of the human intestinal microbial ecosystem. AX microcapsules were mainly (70%) degraded in the ascending colon. The fermentation was completed in the descending colon, increasing the production of acetic, propionic, and butyric acids. In the three regions of the colon, the fermentation of AX microcapsules significantly increased populations of Bifidobacterium and Lactobacillus and decreased the population of Enterobacteriaceae. In addition, the results found in this in vitro model showed that the AX microcapsules could resist the simulated conditions of the upper gastrointestinal system and be a carrier for insulin delivery to the colon. The pharmacological activity of insulin-loaded AX microcapsules was evaluated after oral delivery in diabetic rats. AX microcapsules lowered the serum glucose levels in diabetic rats by 75%, with insulin doses of 25 and 50 IU/kg. The hypoglycemic effect and the insulin levels remained for more than 48 h. Oral relative bioavailability was 13 and 8.7% for the 25 and 50 IU/kg doses, respectively. These results indicate that AX microcapsules are a promising microbiota-activated system for oral insulin delivery in the colon.