Efficacy of inhaled human insulin in type 1 diabetes mellitus: a randomised proof-of-concept study

Muco-Adhesive and Muco-Penetrative Formulations for the Oral Delivery of Insulin

Insulin, a pivotal anabolic hormone, regulates glucose homeostasis by facilitating the conversion of blood glucose to energy or storage. Dysfunction in insulin activity, often associated with pancreatic β cells impairment, leads to hyperglycemia, a hallmark of diabetes. Type 1 diabetes (T1D) results from autoimmune destruction of β cells, while type 2 diabetes (T2D) stems from genetic, environmental, and lifestyle factors causing β cell dysfunction and insulin resistance. Currently, insulin therapy is used for most of the cases of T1D, while it is used only in a few persistent cases of T2D, often supplemented with dietary and lifestyle changes. The key challenge in oral insulin delivery lies in overcoming gastrointestinal (GI) barriers, including enzymatic degradation, low permeability, food interactions, low bioavailability, and long-term safety concerns. The muco-adhesive (MA) and muco-penetrative (MP) formulations aim to enhance oral insulin delivery by addressing these challenges. The mucus layer, a hydrogel matrix covering epithelial cells in the GI tract, poses significant barriers to oral insulin absorption. Its structure, composition, and turnover rate influence interactions with insulin and other drug carriers. Some of the few factors that influence mucoadhesion and mucopenetration are particle size, surface charge distribution, and surface modifications. This review discusses the challenges associated with oral insulin delivery, explores the properties of mucus, and evaluates the strategies for achieving excellent MA and MP formulations, focusing on nanotechnology-based approaches. The development of effective oral insulin formulations holds the potential to revolutionize diabetes management, providing patients with a more convenient and patient-friendly alternative to traditional insulin administration methods.

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.

Comparative Analysis of Inhaled Insulin With Other Types in Type 1 Diabetes Mellitus: A Systematic Review and Meta-Analysis

To analyze the effect of Inhaled insulin in Type 1 Diabetes Mellitus and compare it with other routes of administration of Insulin. A systemic search was conducted from the following electronic databases: PubMed/Medline, Cochrane Library, and Google Scholar, from inception to 28th January 2022. All statistical analysis was conducted in Review Manager 5.4.1. All studies meeting inclusion criteria were selected. A random-effect model was used to pool the studies, and the result was reported in the Standard Mean Difference (SMD), Mean Difference (MD), and Risk Ratio (RR) with their corresponding 95% Confidence interval (CI). Thirteen randomized control trials were selected for our meta-analysis. Statistically significant results were obtained for comparing change in weight after insulin administration (MD= -1.08 [-1.21, -0.94]; p< 0.00001; I2= 74%). Other factors assessed were found to be non-significant like HbA1c (SMD= 0.03 [-0.80, 0.86]; p= 0.95; I2= 99%), fasting blood sugar (SMD= -0.31 [-1.52, 0.91]; p= 0.62; I2= 99%) and adverse effects (RR= 1.06 [0.97, 1.16]; p= 0.18; I2= 96%). In this systematic review and meta-analysis, we found that inhaled insulin is equally effective as subcutaneously administered insulin in patients with Type 1 Diabetes. The inhaled insulin was found to show less weight gain and fewer hypoglycemic shifts, with a similar effect on the blood glucose level. No significant difference was observed in the incidence of adverse events.

One hundred years of insulin therapy

At the time of its first clinical application 100 years ago, insulin was presented as the cure for people with diabetes mellitus. That transpired to be an overstatement, yet insulin has proven to be the lifesaver for people with type 1 diabetes mellitus and an essential therapy for many with type 2 diabetes mellitus or other forms of diabetes mellitus. Since its discovery, insulin (a molecule of only 51 amino acids) has been the subject of pharmaceutical research and development that has paved the way for other protein-based therapies. From purified animal-extracted insulin and human insulin produced by genetically modified organisms to a spectrum of insulin analogues, pharmaceutical laboratories have strived to tailor the preparations to the needs of patients. Nonetheless, overall glycaemic control often remains poor as exogenous insulin is still not able to mimic the physiological insulin profile. Circumventing subcutaneous administration and the design of analogues with profiles that mimic that of physiological insulin are ongoing areas of research. Novel concepts, such as once-weekly insulins or glucose-dependent and oral insulins, are on the horizon but their real-world effectiveness still needs to be proven. Until a true cure for type 1 diabetes mellitus is found and the therapeutic arsenal for other forms of diabetes mellitus is expanded, insulin will remain central in the treatment of many people living with diabetes mellitus.

Evaluation of Muc1 Gene Expression at The Time of Implantation in Diabetic Rat Models Treated with Insulin, Metformin and Pioglitazone in The Normal Cycle and Ovulation Induction Cycle

Background

Mucin-1(Muc1) is one of the first molecules in the endometrium that confronts implanting embryos. There is insufficient knowledge about the impacts of diabetes and drugs developed for diabetes treatment on expression of this molecule at the time of implantation. Therefore, this study aimed to investigate the impacts of diabetes and insulin, metformin and pioglitazone on Muc1 expression at the time of implantation.

Materials and Methods

This experimental study was conducted on a total of 63 female Wistar rats divided into 9 groups. To induce type 1diabetes, streptozotocin (STZ) and for induction of type 2 diabetes, nicotinamide (NA) and STZ were injected intraperitoneally. For superovulation, human menopausal gonadotropin (HMG) and human chorionic gonadotropin (HCG) were used. Insulin, metformin and pioglitazone were administered for two weeks. Finally, the endometrial expression of Muc1 was evaluated by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR).

Results

Muc1 expression was non-significantly increased in type 1 and type 2 diabetic groups compared to the control group (P=0.61 and 0.13, respectively); also, it increased in insulin-treated type 1 diabetic group compared to the control group (P=0.0001). Its expression was increased in insulin-treated type 1 diabetic group compared to untreated diabetic group (P=0.001). The expression level of Muc1 was significantly reduced in superovulated and insulintreated type 1 diabetic group compared to the insulin-treated type 1 diabetic group (P=0.001).

Conclusion

One of the causes of fertility problems in diabetes, is changes in Muc1 expression during implantation. On the other hand, the use of insulin in these patients can even lead to overexpression of this gene and worsen the condition. However, these changes can be partially mitigated by assisted reproductive technology (ART) such as superovulation. Also, treatment with metformin and pioglitazone can restore Muc1 expression to near normal levels and has beneficial effects on implantation.

Effects of Periodic Intensive Insulin Therapy: An Updated Review

Background

Traditional insulin treatment for diabetes mellitus with insulin administered subcutaneously yields nonpulsatile plasma insulin concentrations that represent a fraction of normal portal vein levels. Oral hypoglycemic medications result in the same lack of pulsatile insulin response to blood glucose levels. Intensive treatments of significant complications of diabetes are not recommended due to complicated multidrug regimens, significant weight gain, and the high risk of hypoglycemic complications. Consequently, advanced complications of diabetes do not have an effective treatment option because conventional therapy is not sufficient. Intensive insulin therapy (IIT) simulates normal pancreatic function by closely matching the periodicity and amplitude of insulin secretion in healthy subjects; however, the mechanisms involved with the observed improvement are not clearly understood.

Objective

The current review aims to analyze the pathophysiology of insulin secretion, discuss current therapies for the management of diabetes, provides an updates on the recent advancements of IIT, and proposes its mechanism of action.

Methods

A literature search on PubMed, MEDLINE, Embase, and CrossRef databases was performed on multiple key words regarding the history and current variations of pulsatile and IIT for diabetes treatment. Articles reporting the physiology of insulin secretion, advantages of pulsatile insulin delivery in patients with diabetes patients, efficacy and adverse effects of current conventional insulin therapies for the management of diabetes, benefits and shortcomings of pancreas and islet transplantation, or clinical trials on patients with diabetes treated with pulsed insulin therapy or advanced IIT were included for a qualitative analysis and categorized into the following topics: mechanism of insulin secretion in normal subjects and patients with diabetes and current therapies for the management of diabetes, including oral hypoglycemic agents, insulin therapy, pancreas and islet transplantation, pulsed insulin therapy, and advances in IIT.

Results

Our review of the literature shows that IIT improves the resolution of diabetic ulcers, neuropathy, and nephropathy, and reduces emergency room visits. The likely mechanism responsible for this improvement is increased insulin sensitivity from adipocytes, as well as increased insulin receptor expression.

Conclusions

Recent advancements show that IIT is an effective option for both type 1 diabetes mellitus and type 2 diabetes mellitus patient populations. This treatment resembles normal pancreatic function so closely that it has significantly reduced the effects of relatively common complications of diabetes in comparison to standard treatments. Thus, this new treatment is a promising advancement in the management of diabetes. (Curr Ther Res Clin Exp. 2019; 80:XXX–XXX).

Microfluidic droplet liquid reactors for active pharmaceutical ingredient crystallization by diffusion controlled solvent extraction

A novel method for crystallization utilizing solvent/antisolvent extraction in microfluidic droplet liquid reactors has been developed for rapid and low-cost screening of crystal polymorphism (i.e. molecular crystallographic arrangement or internal structure) and habit (i.e. crystallographic shape or external structure). The method involves a ternary solvent system consisting of a dispersed phase of two miscible fluids, one in which the active pharmaceutical ingredient (API) is soluble (solvent) and one in which the API is insoluble (antisolvent). The solvent/antisolvent dispersed phase is immiscible with a third continuous phase. Crystallization of an API, GSK1, was controlled within droplets by altering the rate of solvent extraction from droplets into the continuous phase, thereby decreasing API solubility. Crystal size, habit, and population per droplet were directly impacted by the solvent's rate of extraction. Single crystals were grown in individual droplets by slow extraction of solvent into the surrounding continuous phase, which occurs when crystal growth gradually reduces API concentration such that it is maintained within the metastable zone throughout extraction. Rapid extraction of solvent from droplets results in API concentration significantly exceeding its metastable limit, producing a greater number of crystal nuclei compared to slow extraction conditions. When holding constant solubilized API mass per droplet, crystal sizes were larger for slow extraction rates (l = 96.3, w = 16.6 μm) compared to fast extraction rates (l = 48.8, w = 9.5 μm) as a result of crystal growth occurring on fewer crystal nuclei per droplet. Crystal habit can be controlled by adjusting the solvent extraction rate and consequently the saturation, where minimal saturation resulted in a rhombohedral habit and comparatively higher saturation resulted in an acicular habit with a higher aspect ratio. Antisolvents were tested using two hydrophobic APIs demonstrating the method's capability for rapidly identifying favorable crystal morphologies for downstream manufacturability using miniscule amounts of API.

A comparison of metabolomic changes in type-1 diabetic C57BL/6N mice originating from different sources

Animal models have been used to elucidate the pathophysiology of varying diseases and to provide insight into potential targets for therapeutic intervention. Although alternatives to animal testing have been proposed to help overcome potential drawbacks related to animal experiments and avoid ethical issues, their use remains vital for the testing of new drug candidates and to identify the most effective strategies for therapeutic intervention. Particularly, the study of metabolic diseases requires the use of animal models to monitor whole-body physiology. In line with this, the National Institute of Food and Drug Safety Evaluation (NIFDS) in Korea has established their own animal strains to help evaluate both efficacy and safety during new drug development. The objective of this study was to characterize the response of C57BL/6NKorl mice from the NIFDS compared with that of other mice originating from the USA and Japan in a chemical-induced diabetic condition. Multiple low-dose treatments with streptozotocin were used to generate a type-1 diabetic animal model which is closely linked to the known clinical pathology of this disease. There were no significantly different responses observed between the varying streptozotocin-induced type-1 diabetic models tested in this study. When comparing control and diabetic mice, increases in liver weight and disturbances in serum amino acids levels of diabetic mice were most remarkable. Although the relationship between type-1 diabetes and BCAA has not been elucidated in this study, the results, which reveal a characteristic increase in diabetic mice of all origins are considered worthy of further study.

Oral insulin does not alter gut microbiota composition of NOD mice

BACKGROUND

Oral insulin as a preventive strategy and/or treatment of type 1 diabetes has been the target of much research. Producing oral insulins is a complex and challenging task, with numerous pitfalls, due to physiological, physical, and biochemical barriers. Our aim was to determine the impact of oral insulin on the delicate gut microbiota composition.

METHODS

Female nonobese diabetic mice were given oral porcine insulin 2 times a week from 5 weeks of age for 4 weeks, and then subsequently once a week for 21 weeks, or until euthanized. The mice were divided into groups on a gluten-reduced diet or a standard diet. Gut microbiota composition was analysed based on faecal samples, and the type 1 diabetes incidence of the mice was monitored.

RESULTS

We observed no influence of the oral porcine insulin on the gut microbiota composition of mice on a gluten-reduced or a standard diet at 9 weeks of age. Also, the administration of oral insulin did not influence the incidence of type 1 diabetes at 30 weeks of age.

CONCLUSIONS

Oral porcine insulin does not alter the gut microbiota composition of nonobese diabetic mice on either a gluten-reduced diet or standard diet. Also, the oral porcine insulin did not influence the incidence of type 1 diabetes in the groups.

Cardioprotective effects of pectin-insulin patch in streptozotocin-induced diabetic rats

BACKGROUND

Cardiovascular complications are among the leading causes of morbidity and mortality in diabetes mellitus. Despite the beneficial effects of subcutaneous insulin, reports suggest that the therapy itself precipitates cardiovascular risks due to the high insulin concentration administered. It is therefore necessary to seek alternative routes of insulin administration that may bypass the undesirable effects associated with high plasma insulin concentrations. Accordingly, the present study investigated the effects of a novel transdermal pectin-insulin patch on selected markers of cardiovascular function in diabetes.

METHODS

Pectin-insulin matrix patches (20.0, 40.8, and 82.9 μg/kg) were prepared as described previously. The three formulations were applied to streptozotocin-induced diabetic rats thrice daily. Blood glucose concentrations and mean arterial pressure (MAP) were monitored weekly for 5 weeks. Rats were then killed and blood collected for analysis of the lipid profile, cardiotropin-1, tumor necrosis factor (TNF)-α, and high-sensitivity C-reactive protein (hsCRP).

RESULTS

The patches decreased blood glucose concentrations and diabetes-induced disturbances in lipid profile were attenuated by patch application (82.9 μg/kg). The diabetes-induced increase in MAP was also attenuated in patch (82.9 μg/kg)-treated rats. Patch treatment resulted in a decreased heart weight: body weight ratio, as well as reductions in cardiotropin-1, TNF-α, and hsCRP concentrations.

CONCLUSIONS

Application of the pectin-insulin patch protects against the debilitating cardiovascular effects associated with conventional diabetes treatment. This suggests that the pectin-insulin patch may provide an effective alternative therapeutic approach to the commonly used subcutaneous insulin injections in the management of diabetes.

Fundamentals of aerosol therapy in critical care

Drug dosing in critically ill patients is challenging due to the altered drug pharmacokinetics–pharmacodynamics associated with systemic therapies. For many drug therapies, there is potential to use the respiratory system as an alternative route for drug delivery. Aerosol drug delivery can provide many advantages over conventional therapy. Given that respiratory diseases are the commonest causes of critical illness, use of aerosol therapy to provide high local drug concentrations with minimal systemic side effects makes this route an attractive option. To date, limited evidence has restricted its wider application. The efficacy of aerosol drug therapy depends on drug-related factors (particle size, molecular weight), device factors, patient-related factors (airway anatomy, inhalation patterns) and mechanical ventilation-related factors (humidification, airway). This review identifies the relevant factors which require attention for optimization of aerosol drug delivery that can achieve better drug concentrations at the target sites and potentially improve clinical outcomes.

Review: Current status of the development of inhaled insulin

The most promising alternative route of insulin administration seems to be pulmonary delivery by inhalation. For a maximal rate of absorption insulin must be applied deep into the lung, i.e., into the alveoli. A number of inhalers designed to generate an aerosol with an appropriate particle size for pulmonary delivery are currently in clinical development. The pharmacodynamic effects of insulin formulations administered via the lung are comparable to, or are even faster than, those of subcutaneously injected regular insulin or rapid-acting insulin analogues. The relative biopotency of inhaled insulin is approximately 10%, i.e., the dose of inhaled insulin must be 10 times higher than the dose applied subcutaneously in order to induce a comparable metabolic effect. Clinical trials indicate that metabolic control with this pain free route of insulin administration is at least comparable to that of subcutaneous (sc) insulin therapy. Side effects. observed in human trials, gave rise to safety concerns that have delayed development for several years. Nevertheless, recent long-term safety studies indicate that the increased stimulation of insulin antibody formation stopped after some time and that the observed changes in lung function were minor or reversible. Consequently the first application for an approval of pulmonary insulin has been submitted to the authorities. In summary, it seems as if, after several decades of research, for the first time a feasible alternative route for insulin administration is within Reach.

Review: Inhaled insulin: overcoming barriers to insulin therapy?

nhaled insulin is a new route of insulin delivery that can be used in the treatment of type 1 and type 2 diabetes. It offers an alternative and additional means of insulin administration, and has been received with particular satisfaction by patients who dislike injections. Trials indicate that inhaled insulin can be used effectively for pre-meal bolus intensification of treatment. Pre-meal inhaled insulin with Exubera® has shown faster absorption and similar duration of action to regular subcutaneous insulin with an overall similar glucodynamic effect. Although bioavailability is lower, mainly due to losses in the upper airways, this is compensated for by dose. The commonest side effect reported with inhaled insulin, as with subcutaneous insulin, was hypoglycaemia, almost a quarter of patients noted a cough which settled with continued treatment. Increased antibody titres and changes in lung function return to normal on discontinuation of inhaled insulin. Quality of life scores indicate patient preference for inhaled versus injected insulin, thus increased choice may improve adherence to treatment regimens. However, true cost:benefit analyses have to be undertaken as do studies in children, smokers and people with respiratory conditions, e.g. asthma.

Nano-Therapeutics for the Lung: State-of-the-Art and Future Perspectives

Inhalation of aerosolized compounds is a popular, non-invasive route for the targeted delivery of therapeutic molecules to the lung. Various types of nanoparticles have been used as carriers to facilitate drug uptake and intracellular action in order to treat lung diseases and/or to facilitate lung repair and growth. These include polymeric nanoparticles, liposomes, and dendrimers, among many others. In addition, nanoparticles are sometimes used in combination with small molecules, cytokines, growth factors, and/or pluripotent stem cells. Here we review the rationale and state-of-the-art nanotechnology for pulmonary drug delivery, with particular attention to new technological developments and approaches as well as the challenges associated with them, the emerging advances, and opportunities for future development in this field.

Effects of Nigella sativa L. seed oil on intima-media thickness and Bax and Caspase 3 expression in diabetic rat aorta

OBJECTIVE

Hyperglycaemia is an important risk factor for the development and progression of the macrovascular and microvascular complications that occur in diabetes. The expression of apoptotic markers in the aortic medial layer of diabetic rats and the effects of N. sativa L. seed oil on the expression of these markers were investigated in this study.

METHODS

Four-month-old adult female Wistar rats (n=21) were divided into 3 groups: Group 1, control; Group 2, diabetes and Group 3, diabetes+N. sativa L. seed oil. Group 3 received 0.2 mg/kg/day N. sativa L. seed (black cumin) oil intraperitoneally 6 days per week for 30 days. At the end of the experiment, abdominal and thoracic aortas of all animals were collected and fixed in 10% formalin solution. Then, 5-μm-thick sections were stained with Verhoeff-Van Gieson stain to evaluate Bax and Caspase 3 expression. Tunica intima-media thickness was measured using the stained sections.

RESULTS

There were no significant differences in abdominal or thoracic aortic intima-media thickness among the 3 groups. However, there were significant differences in Bax and Caspase 3 expression in the tunica media of the thoracic and abdominal aortas between Group 1 and Group 2 (p<0.05) and between Group 2 and Group 3 (p<0.05) evaluated with the Kruskal-Wallis and Mann-Whitney U tests.

CONCLUSION

It is understood that N. sativa L. seed oil is effective against diabetes. N. sativa L. seed oil is a plant material and has value for further investigation to develop diabetes treatment strategies for preventing apoptosis in vascular structures.

Immunogenetics of type 1 diabetes mellitus

Type 1 diabetes mellitus (T1DM) is an autoimmune disease arising through a complex interaction of both genetic and immunologic factors. Similar to the majority of autoimmune diseases, T1DM usually has a relapsing remitting disease course with autoantibody and T cellular responses to islet autoantigens, which precede the clinical onset of the disease process. The immunological diagnosis of autoimmune diseases relies primarily on the detection of autoantibodies in the serum of T1DM patients. Although their pathogenic significance remains uncertain, they have the practical advantage of serving as surrogate biomarkers for predicting the clinical onset of T1DM. Type 1 diabetes is a polygenic disease with a small number of genes having large effects (i.e. HLA), and a large number of genes having small effects. Risk of T1DM progression is conferred by specific HLA DR/DQ alleles [e.g., DRB1*03-DQB1*0201 (DR3) or DRB1*04-DQB1*0302 (DR4)]. In addition, HLA alleles such as DQB1*0602 are associated with dominant protection from T1DM in multiple populations. A discordance rate of greater than 50% between monozygotic twins indicates a potential involvement of environmental factors on disease development. Viral infections may play a role in the chain of events leading to disease, albeit conclusive evidence linking infections with T1DM remains to be firmly established. Two syndromes have been described in which an immune-mediated form of diabetes occurs as the result of a single gene defect. These syndromes are termed autoimmune polyglandular syndrome type I (APS-I) or autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), and X-linked poyendocrinopathy, immune dysfunction and diarrhea (XPID). These two syndromes are unique models to understand the mechanisms involved in the loss of tolerance to self-antigens in autoimmune diabetes and its associated organ-specific autoimmune disorders. A growing number of animal models of these diseases have greatly helped elucidate the immunologic mechanisms leading to autoimmune diabetes.

Inhaled insulin--a new delivery for an old drug

Rates of diabetes continue to rise in the United States. It's estimated that more than 25 million people in the United States currently have either type 1 or type 2 diabetes. Insulin is the mainstay of treatment, and a new delivery option is available. In 2014, the U.S. Food and Drug Administration approved Afrezza® inhalation powder, a rapid-acting inhaled form of human insulin, to treat diabetes in adults. This article will provide an overview of the Afrezza system, indications for use, adverse reactions and implications for nurses who work with women with diabetes.

The expanding role of aerosols in systemic drug delivery, gene therapy and vaccination: an update

Until the late 1990s, aerosol therapy consisted of beta₂-adrenergic agonists, anti-cholinergics, steroidal and non-steroidal agents, mucolytics and antibiotics that were used to treat patients with asthma, COPD and cystic fibrosis. Since then, inhalation therapy has matured to include drugs that: (1) are designed to treat diseases outside the lung and whose target is the systemic circulation (systemic drug delivery); (2) deliver nucleic acids that lead to permanent expression of a gene construct, or protein coding sequence, in a population of cells (gene therapy); and (3) provide needle-free immunization against disease (aerosolized vaccination). During the evolution of these advanced applications, it was also necessary to develop new devices that provided increased dosing efficiency and less loss during delivery. This review will present an update on the success of each of these new applications and their devices. The early promise of aerosolized systemic drug delivery and its outlook for future success will be highlighted. In addition, the challenges to aerosolized gene therapy and the need for appropriate gene vectors will be discussed. Finally, progress in the development of aerosolized vaccination will be presented. The continued expansion of the role of aerosol therapy in the future will depend on: (1) improving the bioavailability of systemically delivered drugs; (2) developing gene therapy vectors that can efficiently penetrate the mucus barrier and cell membrane, navigate the cell cytoplasm and efficiently transfer DNA material to the cell nucleus; (3) improving delivery of gene vectors and vaccines to infants; and (4) developing formulations that are safe for acute and chronic administrations.

Further experimentation of inhaled; LANTUS, ACTRAPID and HUMULIN with todays' production systems

BACKGROUND

Several aerosol production systems have been used for aerosol insulin production. However; since the first studies several new models of jet-nebulizers and ultrasound nebulizers have been introduced in the market.

MATERIALS AND METHODS

Three different models of jet-nebulizers (different brands, same properties) and three different ultrasound nebulizers (different brands, same properties). Six residual cups (2 small ≤ 6 ml and 3 large ≤ 8 ml) were used for the jet-nebulizers. The ultrasound nebulizers were used with their facemasks or with their inlets which were included in the purchase package.

RESULTS

Ultrasound nebulizers; LANTUS produces by far the lowest mean droplets (2.44) half the size of the other two drugs (4.43=4.97). GIMA nebulizer is the most efficient producing one third of the droplet size of SHIMED and one second of EASYNEB (2.06<3.15<6.62). Finally, the 4 ml loading concentration is more suitable for supporting the production of smaller droplets (3.65<4.24). Drugs and nebulizers act interactively yielding very large droplets when ACTRAPID and HUMULIN are administered in joint with SHIMED nebulizer (9.59=7.72). Jet-nebulizers; HUMULIN again is the least preferred insulin since it hardly reaches the low but equal performance of others at the loading level of 6 ml. Residual cups E and B produce uniquely lower mean droplets at loading level 6.

CONCLUSIONS

Ultrasound nebulizers; the best suggested combination should be LANTUS insulin, GIMA nebulizer administered at loading dose of 4 ml jet-nebulizers. A global review can give the best combination: the lowest mean droplets are produced when the drugs LANTUS (mostly) and ACTRAPID are administered, applying the SUNMIST nebulizer in concert with residual cup B at loading levels of 6 ml.

Young and Elderly Type 2 Diabetic Patients Inhaling Insulin with the AERx® Insulin Diabetes Management System: A Pharmacokinetic and Pharmacodynamic Comparison

The objective of this study was to compare the pharmacokinetics (PK), pharmacodynamics (PD), and safety of inhaled insulin delivered by the AERx iDMS in young and elderly patients with type 2 diabetes. Twenty-seven young (18-45 years, inclusive) and 28 elderly (>/= 65 years) type 2 diabetic patients were enrolled in this study. A single inhalation of 1.57 mg (45 IU, effect comparable to 6 s.c. units) of regular human insulin was administered to each patient on each of 2 dosing days, and blood samples were drawn up to 360 minutes postdosing to generate the PK/PD curves. AUC(0-360 min) and Cmax values of inhaled insulin were comparable between young and elderly subjects (p = 0.476 for AUC(0-360 min) and p = 0.414 for Cmax). However, the elderly group had significantly less glucose reduction, as indicated by plasma glucose AOC(0-360) (area over the curve) values (p = 0.011). The intrasubject variability of inhaled insulin using the AERx iDMS was similar for young and elderly subjects and was similar to what has previously been reported for soluble insulin administered subcutaneously. Inhaled insulin was well tolerated in these patients, and no changes in pulmonary function tests were observed. A single inhalation of insulin using the AERx iDMS demonstrated comparable insulin PK profiles between the elderly and young type 2 patients but less glucose reduction in the elderly. Based on these results, elderly diabetic patients may need to inhale more insulin than young patients to achieve similar glycemic control. Long-term clinical trials using the AERx device will be useful to study age-related differences.

Inhaled Human [rDNA Origin] Insulin, a Novel Formulation for Diabetes Mellitus

Diabetic complications have been reduced significantly with the introduction of insulin more than 8 decades prior. Despite the proven benefits of normal glycemic levels, patients are deterred by the inconvenience and expect worse pain than there is on average with multiple daily insulin injections. Inhaled insulin was approved by the Food and Drug Administration in early 2006 and is a novel product that introduces inhaled insulin as an alternate to the traditional subcutaneous delivery system, and hence could potentially improve patient compliance. The objective of this article is to review the clinical pharmacology, pharmacokinetic and pharmacodynamic properties, clinical efficacy, and tolerability of inhaled insulin.

Can inhaled insulin be used for the treatment of diabetes mellitus?

Reluctance to start and adequately titrate subcutaneous insulin are major reasons why many patients with diabetes mellitus are insufficiently metabolically controlled. Pulmonary insulin administration has the advantage over subcutaneous insulin in that it is noninvasive, seems better accepted by the diabetic population and exerts equal efficacy in terms of glycemic control. As such, inhaled insulin has the potential to increase the diabetic (Type 2) patient's willingness to commence and adhere to insulin therapy. Inhaled insulin's short duration of action makes it suitable for prandial administration provided that basal insulin requirements are met by residual b-cell function, or by supplemental long-acting subcutaneous insulin. In clinical trials, inhaled insulin is comparable to short-acting subcutaneous insulin with regard to efficacy and hypoglycemic risk. Adverse effects associated with inhaled insulin include dry cough, which tends to diminish over time, a slight drop in pulmonary function that does not progress and is reversible in most patients if treatment is discontinued, and increased insulin antibody formation, albeit without clinical sequelae. Long-term safety remains an issue for a product intended to be used chronically for many years. Exubera((R)) was thus far the only inhaled insulin product to receive approval in the USA and Europe for use in adults with Type 1 or Type 2 diabetes, but was recently withdrawn from the market. At present it is unclear how this decision will affect programs from other companies with inhaled insulin products under development.

Humoral autoimmunity in type 1 diabetes: prediction, significance, and detection of distinct disease subtypes

Type 1 diabetes mellitus (T1D) is an autoimmune disease encompassing the T-cell-mediated destruction of pancreatic β cells and the production of autoantibodies against islet proteins. In humoral autoimmunity in T1D, the detection of islet autoantibodies and the examination of their associations with genetic factors and cellular autoimmunity constitute major areas in both basic research and clinical practice. Although insulin is a key autoantigen and may be primus inter pares in importance among T1D autoantigens, an abundant body of research has also revealed other autoantigens associated with the disease process. Solid evidence indicates that autoantibodies against islet targets serve as key markers to enroll newly diagnosed T1D patients and their family members in intervention trials aimed at preventing or halting the disease process. The next challenge is perfecting mechanistic bioassays to be used as end points for disease amelioration following immunomodulatory therapies aimed at blocking immune-mediated β-cell injury and, in turn, preserving β-cell function in type 1 diabetes mellitus.

In pursuit of excellence in diabetes care: trends in insulin delivery

Diabetes mellitus has been estimated to affect 2.9 million people in the UK. Large-scale clinical trials conclusively demonstrate that elevated blood glucose levels are associated with an increased risk of micro- and macrovascular complications. The high rates of morbidity and mortality associated with this condition demonstrate how important effective glycaemic control is. Subcutaneous insulin injection continues to be the mainstay of therapy for all people with type 1 diabetes mellitus and the majority of individuals with type 2 diabetes mellitus. However, there are a number of barriers to insulin therapy. For example, conventional insulin delivery is arguably time consuming. Furthermore, it has been associated with common errors, such as inaccurate dosing and administration (National Patient Safety Agency, 2010). Insulin pen devices have various advantages over conventional delivery. Their ease of use and incorporation into busy lifestyles may improve diabetes control with much less effort, while maintaining adherence and quality of life. Research in insulin delivery shows there is a prospect of needle-free delivery in the near future. Despite such progress, the role of the healthcare professionals in involving, assessing, supporting and educating people having insulin therapy, including the attainment of the agreed blood glucose levels, cannot be overestimated.

Pulmonary delivery of dry powders to rats: tolerability limits of an intra-tracheal administration model

The inhaled route is increasingly developed to deliver locally acting or systemic therapies, and rodent models are used to assess tolerance before clinical studies. Endotracheal intubation of rats with a probe which generates powder aerosols enables controlled administration of drug directly into the respiratory tract. However, preliminary observations of intratracheal powder administration procedures have raised concerns with regard to pulmonary safety. The aim of the present work was to evaluate the safety of intra-tracheal administration of dry powder in a rat model. Sixty animals were administered various volumes of air alone, lactose or magnesium stearate through a Microsprayer(®) (Pencentury, USA). The mass of powder actually delivered to each animal was calculated. Rats were sacrificed immediately after administration, and the lungs, trachea and larynx were removed and examined for gross pathology. The mass of powder delivered varied, the full dose being rarely delivered. About one third of the administration procedures resulted in respiratory failure, and macroscopic pulmonary lesions were observed in about 55% of animals. Lung damages were observed with air alone, lactose and magnesium stearate. In conclusion, artifacts observed with this technique may limit the relevance of the model. These observations are particularly important in the context of regulatory toxicity studies.

Inhaled insulin: too soon to be forgotten?

Inhalation is a potentially viable route of administration for numerous agents. In diabetes mellitus, the need for frequent injections to achieve ideal glycemic control remains a significant limitation for initiating and complying with insulin therapy in a large number of patients. To overcome this barrier, inhaled insulin was developed. The inhalation form of regular human insulin has been tested and administered in a large number of trials. Respiratory capacity was evaluated in patients with normal lung parenchyma in whom inhaled insulin was administered without complications. However, issues like cost, bulky device, fear for lung safety, and the small number of studies in subjects with underlying respiratory disease prevented widespread use of this new mode of delivery. In the present review, we will suggest a number of methods that could be applied in this form of administration to maximize drug absorption and fully exploit the advantages of this route of administration.

Nanocarriers for pulmonary administration of peptides and therapeutic proteins

Peptides and therapeutic proteins have been the target of intense research and development in recent years by the pharmaceutical and biotechnology industry. Preferably, they are administered through the parenteral route, which is associated with reduced patient compliance. Formulations for noninvasive administration of peptides and therapeutic proteins are currently being developed. Among them, inhalation appears as a promising alternative for the administration of such products. Several formulations for pulmonary delivery are in various stages of development. Despite positive results, conventional formulations have some limitations such as reduced bioavailability and side effects. Nanocarriers may be an alternative way to overcome the problems of conventional formulations. Some nanocarrier-based formulations of peptides and therapeutic proteins are currently under development. The results obtained are promising, revealing the usefulness of these systems in the delivery of such drugs.

Successful treatment of severe subcutaneous insulin resistance with inhaled insulin therapy

The potential of inhaled insulin therapy for severe resistance to subcutaneous insulin was tested in a 7-yr old boy with type 1 diabetes mellitus. The efficiency of 1 mg inhaled insulin (Exubera) was examined by a 4-h euglycemic clamp study. During the clamp, the glucose infusion rate started to increase 25 min after inhalation and peaked 120 min after inhalation. Subsequently, a trial of inhaled insulin monotherapy was initiated consisting of pre-meal inhalations and one inhalation during the night. Since glycemic control remained fair (HbA1c approximately 8.5%), this therapy was continued. Over the ensuing 18 months, mild keto-acidosis occurred twice during gastro-enteritis. Inhaled insulin was well tolerated and pulmonary function did not deteriorate. We conclude that severe resistance to subcutaneous insulin does not preclude sufficient absorption of insulin delivered by pulmonary.

Pulmonary targeting of nanoparticle drug matrices

BACKGROUND

Nanoparticle drug matrices using lipids or liposomes, with diameters of 40-300 nm, have recently been developed to encapsulate drugs like Insulin, Budesonide, and Rifampicin for pulmonary delivery raising interest in their regional lung deposition.

METHODS

Lung deposition has so far been modeled using a one-dimensional transport equation, with or without moving airway boundaries, and a lumped deposition term for particle diffusion, sedimentation, and impaction. Here, a two-dimensional transport model has been developed with an explicit treatment of radial diffusion, the primary mechanism for nanoparticle deposition. Regional lung deposition was calculated using Weibel's whole lung model geometry during normal breathing and medical inhalation cycles.

CONCLUSIONS

Model predictions agree well with measurements of total and pulmonary lung deposition for particles of 10 nm to 10 μm, with earlier models incorporating moving boundaries and aerosol dynamics, and with the reported regional lung deposition of inhaled dry powder insulin. To simulate medical inhalation, the model was run with inhalation times from 2-6 sec and breath hold from 0-10 sec. A high and relatively invariant pulmonary deposition fraction between 70 and 95% was predicted for a broad nanoparticle size range (50-200 nm) for inhalation cycles with breathing rate between 500 and 2000 cm(3) sec(-1) and breath hold of 5-10 sec. Thus, nanoparticles may be able to deliver consistent lung doses, over modest breath hold periods, even with intrapatient variability in breathing rate. A linearized nomogram was provided as a heuristic for design of nanoparticle drug matrices to target the pulmonary lung.

Inhaled insulin-intrapulmonary, intranasal, and other routes of administration: mechanisms of action

BACKGROUND

After discovery of insulin as a hypoglycemic agent in 1921 various routes of administration to control blood glucose were attempted. These included subcutaneous, oral, rectal, sublingual, buccal, transdermal, vaginal, intramuscular, intrapulmonary and intranasal delivery systems. While each delivery system controlled hyperglycemia the subcutaneous route was given priority until 2006 when the Federal Drug Administration (FDA) approved the first commercially available pulmonary inhaled insulin.

METHODS

A review of major publications dealing with intrapulmonary administration of insulin was made to understand the physiological basis for its use, its efficacy in controlling hyperglycemia, its side effects and a comparison of its efficacy with other delivery methods.

RESULTS

The large surface area of the lung, its good vascularization, capacity for solute exchange and ultra thin membranes of alveolar epithelia are unique features that facilitate pulmonary insulin delivery. Large lung surface area ( approximately 75 m(2)) and thin alveolar epithelium ( approximately 0.1-0.5 microm) permit rapid drug absorption. First pass metabolism avoids gastrointestinal tract metabolism. Lung drug delivery depends upon a complex of factors including size, shape, density, charge and pH of delivery entity, velocity of entry, quality of aerosol deposition, character of alveoli, binding characteristics of aerosol on the alveolar surface, quality of alveolar capillary bed and its subsequent vascular tree. Many studies were performed to optimize each of these factors using several delivery systems to enhance pulmonary absorption. Availability was about 80% of subcutaneous administration with peak activity within 40-60 min of administration. Intranasal insulin delivery faces a smaller surface area ( approximately 180 cm(2)) with quite different absorption characteristics in nasal epithelium and its associated vasculature. Absorption depends upon many factors including composition and character of nasal mucus. Absorption of intranasal insulin resulted in a faster absorption time course than with subcutaneous insulin.

INTERPRETATION

After many studies the FDA approved Pfizer's product, Exubera, for intrapulmonary insulin delivery. While the system was effective its expense and putative side effects caused the drug company to withdraw the drug from the marketplace. Attempts by other pharmaceutical companies to use intrapulmonary insulin delivery are presently being made as well as some minor attempts to use intranasal delivery systems.

STAR 3 randomized controlled trial to compare sensor-augmented insulin pump therapy with multiple daily injections in the treatment of type 1 diabetes: research design, methods, and baseline characteristics of enrolled subjects

BACKGROUND

Sensor-augmented pump therapy (SAPT) integrates real-time continuous glucose monitoring (RT-CGM) with continuous subcutaneous insulin infusion (CSII) and offers an alternative to multiple daily injections (MDI). Previous studies provide evidence that SAPT may improve clinical outcomes among people with type 1 diabetes. Sensor-Augmented Pump Therapy for A1c Reduction (STAR) 3 is a multicenter randomized controlled trial comparing the efficacy of SAPT to that of MDI in subjects with type 1 diabetes.

METHODS

Subjects were randomized to either continue with MDI or transition to SAPT for 1 year. Subjects in the MDI cohort were allowed to transition to SAPT for 6 months after completion of the study. SAPT subjects who completed the study were also allowed to continue for 6 months. The primary end point was the difference between treatment groups in change in hemoglobin A1c (HbA1c) percentage from baseline to 1 year of treatment. Secondary end points included percentage of subjects with HbA1c < or =7% and without severe hypoglycemia, as well as area under the curve of time spent in normal glycemic ranges. Tertiary end points include percentage of subjects with HbA1c < or =7%, key safety end points, user satisfaction, and responses on standardized assessments.

RESULTS

A total of 495 subjects were enrolled, and the baseline characteristics similar between the SAPT and MDI groups. Study completion is anticipated in June 2010.

CONCLUSIONS

Results of this randomized controlled trial should help establish whether an integrated RT-CGM and CSII system benefits patients with type 1 diabetes more than MDI.

Inhaled insulin: overview of a novel route of insulin administration

Diabetes is a chronic disease characterized by inadequate insulin secretion with resulting hyperglycemia. Diabetes complications include both microvascular and macrovascular disease, both of which are affected by optimal diabetes control. Many individuals with diabetes rely on subcutaneous insulin administration by injection or continuous infusion to control glucose levels. Novel routes of insulin administration are an area of interest in the diabetes field, given that insulin injection therapy is burdensome for many patients. This review will discuss pulmonary delivery of insulin via inhalation. The safety of inhaled insulin as well as the efficacy in comparison to subcutaneous insulin in the various populations with diabetes are covered. In addition, the experience and pitfalls that face the development and marketing of inhaled insulin are discussed.

Cell-based multiscale computational modeling of small molecule absorption and retention in the lungs

PURPOSE

For optimizing the local, pulmonary targeting of inhaled medications, it is important to analyze the relationship between the physicochemical properties of small molecules and their absorption, retention and distribution in the various cell types of the airways and alveoli.

METHODS

A computational, multiscale, cell-based model was constructed to facilitate analysis of pulmonary drug transport and distribution. The relationship between the physicochemical properties and pharmacokinetic profile of monobasic molecules was explored. Experimental absorption data of compounds with diverse structures were used to validate this model. Simulations were performed to evaluate the effect of active transport and organelle sequestration on the absorption kinetics of compounds.

RESULTS

Relating the physicochemical properties to the pharmacokinetic profiles of small molecules reveals how the absorption half-life and distribution of compounds are expected to vary in different cell types and anatomical regions of the lung. Based on logP, pK(a) and molecular radius, the absorption rate constants (K(a)) calculated with the model were consistent with experimental measurements of pulmonary drug absorption.

CONCLUSIONS

The cell-based mechanistic model developed herein is an important step towards the rational design of local, lung-targeted medications, facilitating the design and interpretation of experiments aimed at optimizing drug transport properties in lung.

A valuation of patients' willingness-to-pay for insulin delivery in diabetes

OBJECTIVES

The aim of this study was to determine the insulin-delivery system and the attributes of insulin therapy that best meet patients' preferences, and to estimate patients' willingness-to-pay (WTP) for them.

METHODS

This was a cross-sectional discrete choice experiment (DCE) study involving 378 Canadian patients with type 1 or type 2 diabetes. Patients were asked to choose between two hypothetical insulin treatment options made up of different combinations of the attribute levels. Regression coefficients derived using conditional logit models were used to calculate patients' WTP. Stratification of the sample was performed to evaluate WTP by predefined subgroups.

RESULTS

A total of 274 patients successfully completed the survey. Overall, patients were willing to pay the most for better blood glucose control followed by weight gain. Surprisingly, route of insulin administration was the least important attribute overall. Segmented models indicated that insulin naïve diabetics were willing to pay significantly more for both oral and inhaled short-acting insulin compared with insulin users. Surprisingly, type 1 diabetics were willing to pay $C11.53 for subcutaneous short-acting insulin, while type 2 diabetics were willing to pay $C47.23 to avoid subcutaneous short-acting insulin (p < .05). These findings support the hypothesis of a psychological barrier to initiating insulin therapy, but once that this barrier has been overcome, they accommodate and accept injectable therapy as a treatment option.

CONCLUSIONS

By understanding and addressing patients' preferences for insulin therapy, diabetes educators can use this information to find an optimal treatment approach for each individual patient, which may ultimately lead to improved control, through improved compliance, and better diabetes outcomes.

Preparation of honokiol-loaded chitosan microparticles via spray-drying method intended for pulmonary delivery

It has been demonstrated that spray-drying is a powerful method to prepare dry powders for pulmonary delivery. This paper prepared dispersible dry powders based on chitosan and mannitol containing honokiol nanoparticles as model drug. The results showed that the prepared microparticles are almost spherical and have appropriate aerodynamic properties for pulmonary delivery (aerodynamic diameters was between 2.8-3.3 microm and tapped density ranging from 0.14-0. 18 g/cm(3)). Moreover, surface morphology and aerodynamic properties of the powders were strongly affected by the content of mannitol. Fourier transform infra-red (FTIR) spectrum of powders indicated that the honokiol nanoparticles were successfully incorporated into microparticles. In vitro drug release profile was also observed. The content of mannitol in powders significantly influenced the release rate of honokiol from matrices.

A comparison between simplified and intensive dose-titration algorithms using AIR inhaled insulin for insulin-naive patients with type 2 diabetes in a randomized noninferiority trial

BACKGROUND

Insulin initiation and optimization is a challenge for patients with type 2 diabetes. Our objective was to determine whether safety and efficacy of AIR inhaled insulin (Eli Lilly and Co., Indianapolis, IN) (AIR is a registered trademark of Alkermes, Inc., Cambridge, MA) using a simplified regimen was noninferior to an intensive regimen.

METHODS

This was an open-label, randomized study in insulin-naive adults not optimally controlled by oral antihyperglycemic medications. Simplified titration included a 6 U per meal AIR insulin starting dose. Individual doses were adjusted at mealtime in 2-U increments from the previous day's four-point self-monitored blood glucose (SMBG) (total < or =6 U). Starting Air insulin doses for intensive titration were based on fasting blood glucose, gender, height, and weight. Patients conducted four-point SMBG daily for the study duration. Insulin doses were titrated based on the previous 3 days' mean SMBG (total < or =8 U).

RESULTS

End point hemoglobin A1C (A1C) was 7.07 +/- 0.09% and 6.87 +/- 0.09% for simplified (n = 178) and intensive (n = 180) algorithms, respectively. Noninferiority between algorithms was not established. The fasting blood glucose (least squares mean +/- standard error) values for the simplified (137.27 +/- 3.42 mg/dL) and intensive (133.13 +/- 3.42 mg/dL) algorithms were comparable. Safety profiles were comparable. The hypoglycemic rate at 4, 8, 12, and 24 weeks was higher in patients receiving intensive titration (all P < .0001). The nocturnal hypoglycemic rate for patients receiving intensive titration was higher than for those receiving simplified titration at 8 (P < 0.015) and 12 weeks (P < 0.001).

CONCLUSIONS

Noninferiority between the algorithms, as measured by A1C, was not demonstrated. This finding re-emphasizes the difficulty of identifying optimal, simplified insulin regimens for patients.

Comparison of prandial AIR inhaled insulin alone to intensified insulin glargine alone and to AIR insulin plus intensified insulin glargine in patients with type 2 diabetes previously treated with once-daily insulin glargine

BACKGROUND

Patients with type 2 diabetes often initiate insulin with once-daily basal insulin. Over time, many patients intensify their insulin regimens in an attempt to attain and sustain glycemic targets. This study compares three intensification approaches: changing insulin glargine to preprandial AIR inhaled insulin (developed by Alkermes, Inc. [Cambridge, MA] and Eli Lilly and Company [Indianapolis, IN]; AIR is a registered trademark of Alkermes, Inc.), intensifying glargine via validated titration algorithms (IG), or adding AIR insulin while intensifying glargine (AIR + IG).

METHODS

Five hundred sixty patients with hemoglobin A(1c) (A1C) of 7.5-10.5%, on one or more antihyperglycemic medications, and on once-daily insulin glargine for > or =4 months were randomly allocated to one of the three treatments lasting 52 weeks. The primary objective assessed between-group differences in A1C mean change from baseline to 24 weeks using last-observation-carried-forward (LOCF) in the intent-to-treat population.

RESULTS

At 24 weeks, A1C was reduced from a mean baseline of 8.5% to 7.7%, 7.9%, and 7.5% for the AIR, IG, and AIR + IG groups, respectively. AIR produced 0.20% greater A1C decrease than IG (least-squares mean difference = -0.20%; 95% confidence interval [CI], -0.39, -0.02). AIR + IG had a 0.35% greater A1C decrease versus IG (95% CI, -0.57, -0.13). The -0.15% difference between AIR + IG versus AIR was not significant (P < 0.198). More hypoglycemia categorized as severe occurred with AIR alone versus IG alone at LOCF end points. More nocturnal hypoglycemia occurred with IG alone versus AIR alone and AIR + IG.

CONCLUSIONS

Preprandial inhaled insulin provides an alternative for patients not optimized on insulin glargine alone. Glycemic control, hypoglycemic risk, delivery preference, and regimen complexity must be considered when selecting insulin initiation and optimization regimens.

WITHDRAWN: Inhaled insulin in diabetes mellitus

BACKGROUND

Insulin therapy often relies on multiple daily injections of insulin. However this is a considerable burden to many people with diabetes and adherence to such an insulin regimen can be difficult to maintain, hence compromising optimal glycaemic control. Also, short acting injected insulin is absorbed more slowly than insulin released by the normal pancreas in response to a meal. Inhaled insulin has the potential to reduce the number of injections to perhaps one long-acting insulin per day, and provide a closer match to the natural state, by more rapid absorption from the lung.

OBJECTIVES

To compare the efficacy, adverse effects and patient acceptability of inhaled versus injected insulin.

SEARCH STRATEGY

A sensitive search strategy for randomised controlled or cross-over trials was combined with key terms for inhaled insulins. Databases searched were: The Cochrane Library, MEDLINE, PubMed, EMBASE, Science Citation Index, BIOSIS, Web of Science Proceedings, National Research Register UK, Current Controlled Trials, ClinicalTrials.gov, Conference Papers Index, LexisNexis, and web sites of the ADA and EASD were searched for recent meeting abstracts. Reference lists and journals were handsearched. There were no language restrictions on searching. Manufacturers of inhaled insulin were also contacted. Date of last search October 2002.

SELECTION CRITERIA

Only randomised controlled trials with parallel groups or controlled cross-over trials, including type 1 or type 2 diabetic patients of any age treated with insulin, were considered eligible. The minimum trial duration considered was 10 weeks, as this is the time taken for glycated haemoglobin to reliably reflect changes in glycaemic control.

DATA COLLECTION AND ANALYSIS

Trial selection and evaluation of study quality was performed independently by two reviewers. The quality of reporting of each trial was assessed according to a modification of the criteria outlined in Centre for Reviews and Dissemination (CRD) Report 4, Spitzer; and Jadad.

MAIN RESULTS

Six randomised controlled trials were found and the overall number of participants was 1191. Three trials included patients with type 1 diabetes and three with type 2 diabetes. Three trials had a duration of 24 weeks, and three of 12 weeks. All were open label. There was insufficient information to determine the study quality. Results for HbA1c were similar for all trials, in that all showed comparable glycaemic control for inhaled insulin compared to an entirely subcutaneous regimen. All trials that reported patient satisfaction and quality of life showed that these were significantly greater in the inhaled insulin group. Overall there was no difference in total hypoglycaemic episodes between the groups, but one trial showed a statistically significant increase in severe hypoglycaemic episodes for the inhaled insulin group. No adverse pulmonary effects were observed in any of the studies, but longer follow-up will be required to be sure that there are no adverse side-effects. Cavets include: few studies published in full (so quality could not be assessed), and only two studies used the same basal regimen in both the inhaled and injected groups.

AUTHORS' CONCLUSIONS

Inhaled insulin taken before meals, in conjunction with an injected basal insulin, has been shown to maintain glycaemic control comparable to that of patients taking multiple daily injections. The key benefit appears to be that patient satisfaction and quality of life are significantly improved, presumably due to the reduced number of daily injections required. However, the patient satisfaction data is based on five trials, of which only two have been published in full; also the three trials containing quality of life data are all only published in abstract form at present. In addition, longer term pulmonary safety data are still needed. Also, the lower bioavailability, and hence higher doses of inhaled insulin required, may make it less cost-effective than injected insulin.

Insulin delivery systems: reducing barriers to insulin therapy and advancing diabetes mellitus treatment

Insulin therapy is integral to the treatment of diabetes mellitus. Epidemiologic studies have shown its benefits both in terms of improving glycemic control and reducing the risk for long-term diabetic complications for both type 1 and type 2 diabetes. Despite these benefits, barriers to insulin therapy are well documented and include perceived inconvenience, needle anxiety, and portability of device. Historically, patients have often used a vial-and-syringe delivery system to inject a subcutaneous dose of insulin. However, modern regimens provide various choices of delivery systems for prescribers and patients, thus enabling treatment to be tailored to address most patient needs and concerns. Two key alternative delivery systems are now widely available: subcutaneous injection using a pen device, and subcutaneous insulin infusion. In the future inhalations systems for regular human insulin may also become available to patients. Developments in these insulin-delivery systems can improve patients' perceptions of, and experiences with, insulin therapy, potentially reducing barriers to insulin initiation in patients with type 2 diabetes, and also improving aspects of quality of life for those already on an insulin-based regimen.

Intersession variability in single-breath diffusing capacity in diabetics without overt lung disease

RATIONALE

American Thoracic Society guidelines state that a 10% or greater intersession change in diffusing capacity of the lung (DL(CO)) should be considered clinically significant. However, little is known about the short-term intersession variability in DL(CO) in untrained subjects or how variability is affected by rigorous external quality control.

OBJECTIVES

To characterize the intersession variability of DL(CO) and the effect of different quality control methods in untrained individuals without significant lung disease.

METHODS

Data were pooled from the comparator arms of 14 preregistration trials of inhaled insulin that included nonsmoking diabetic patients without significant lung disease. A total of 699 participants performed repeated DL(CO) measurements using a highly standardized technique. A total of 948 participants performed repeated measurements using routine clinical testing.

MEASUREMENTS AND MAIN RESULTS

The mean intersession absolute change in DL(CO) using the highly standardized method was 1.45 ml/minute/mm Hg (5.64%) compared with 2.49 ml/minute/mm Hg (9.52%) in the routine testing group (P < 0.0001 for both absolute and percent difference). The variability in absolute intersession change in DL(CO) increased with increasing baseline DL(CO) values, whereas the absolute percentage of intersession change was stable across baseline values. Depending on the method, 15.5 to 35.5% of participants had an intersession change of 10% or greater. A 20% or greater threshold would reduce this percentage of patients to 1 to 10%.

CONCLUSIONS

Intersession variability in DL(CO) measurement is dependent on the method of testing used and baseline DL(CO). Using a more liberal threshold to define meaningful intersession change may reduce the misclassification of normal variation as abnormal change.

Recent challenges in insulin delivery systems: a review

Relatively, a large percentage of world population is affected by diabetes mellitus, out of which approximately 5-10% with type 1 diabetes while the remaining 90% with type 2. Insulin administration is essential for type 1 patients while it is required at later stage by the patients of type 2. Current insulin delivery systems are available as transdermal injections which may be considered as invasive. Several non-invasive approaches for insulin delivery are being pursued by pharmaceutical companies to reduce the pain, and hypoglycemic incidences associated with injections in order to improve patient compliance. While any new insulin delivery system requires health authorities' approval, to provide long term safety profile and insuring patients' acceptance. The inhalation delivery system Exubera((R)) has already become clinically available in the United States and Europe for patients with diabetes as non-invasive delivery system.

Protein therapeutics: a summary and pharmacological classification

Once a rarely used subset of medical treatments, protein therapeutics have increased dramatically in number and frequency of use since the introduction of the first recombinant protein therapeutic--human insulin--25 years ago. Protein therapeutics already have a significant role in almost every field of medicine, but this role is still only in its infancy. This article overviews some of the key characteristics of protein therapeutics, summarizes the more than 130 protein therapeutics used currently and suggests a new classification of these proteins according to their pharmacological action.

Efficacy of pulmonary insulin delivery in diabetic rats: use of a model-based approach in the evaluation of insulin powder formulations

The potential of N-trimethyl chitosan (TMC) with two degrees of quaternization (DQ), TMC20 (DQ 20%, as a mucoadhesive) and TMC60 (DQ 60%, as a mucoadhesive and a permeation enhancer), and dextran (as a non-mucoadhesive and non-permeation enhancer) microparticles as carriers for pulmonary delivery of insulin was studied in diabetic rats. The impact of the powder formulation on insulin bioavailability and its pharmacological effect was evaluated using a population pharmacokinetic-pharmacodynamic (PKPD) model. Insulin-loaded microparticles were prepared by a supercritical fluid (SCF) drying technique. They had a median volume diameter and median volume aerodynamic diameter of about 6-10 microm and 4 microm, respectively. The PK of insulin in the diabetic rats was analyzed by a one-compartment disposition model and the PD was described by the minimal model of glucose disappearance. The bioavailability of the pulmonarily administered dextran-, TMC20- and TMC60-insulin microparticles relative to subcutaneously (SC) administered insulin, was 0.48, 0.59 and 0.95, respectively. Histological examinations of the rats' lungs did not show any local adverse reactions after single administration of insulin powders. The pharmacodynamic model could describe the insulin-glucose relationship and pharmacodynamic efficiency of insulin formulations, which was about 0.6(*)10(-5) ml/microU, irrespective of the formulations. The current findings suggest that TMC microparticles are a promising vehicle for pulmonary delivery of insulin.