Comparative pharmacodynamic and pharmacokinetic characteristics of subcutaneous insulin glulisine and insulin aspart prior to a standard meal in obese subjects with type 2 diabetes

Application of Nanoparticles: Diagnosis, Therapeutics, and Delivery of Insulin/Anti-Diabetic Drugs to Enhance the Therapeutic Efficacy of Diabetes Mellitus

Diabetes mellitus (DM) is a chronic metabolic disorder of carbohydrates, lipids, and proteins due to a deficiency of insulin secretion or failure to respond to insulin secreted from pancreatic cells, which leads to high blood glucose levels. DM is one of the top four noncommunicable diseases and causes of death worldwide. Even though great achievements were made in the management and treatment of DM, there are still certain limitations, mainly related to the early diagnosis, and lack of appropriate delivery of insulin and other anti-diabetic agents. Nanotechnology is an emerging field in the area of nanomedicine and NP based anti-diabetic agent delivery is reported to enhance efficacy by increasing bioavailability and target site accumulation. Moreover, theranostic NPs can be used as diagnostic tools for the early detection and prevention of diseases owing to their unique biological, physiochemical, and magnetic properties. NPs have been synthesized from a variety of organic and inorganic materials including polysaccharides, dendrimers, proteins, lipids, DNA, carbon nanotubes, quantum dots, and mesoporous materials within the nanoscale size. This review focuses on the role of NPs, derived from organic and inorganic materials, in the diagnosis and treatment of DM.

A Comprehensive Review of the Evolution of Insulin Development and Its Delivery Method

The year 2021 marks the 100th anniversary of the momentous discovery of insulin. Through years of research and discovery, insulin has evolved from poorly defined crude extracts of animal pancreas to recombinant human insulin and analogues that can be prescribed and administered with high accuracy and efficacy. However, there are still many challenges ahead in clinical settings, particularly with respect to maintaining optimal glycemic control whilst minimizing the treatment-related side effects of hypoglycemia and weight gain. In this review, the chronology of the development of rapid-acting, short-acting, intermediate-acting, and long-acting insulin analogues, as well as mixtures and concentrated formulations that offer the potential to meet this challenge, are summarized. In addition, we also summarize the latest advancements in insulin delivery methods, along with advancement to clinical trials. This review provides insights on the development of insulin treatment for diabetes mellitus that may be useful for clinicians in meeting the needs of their individual patients. However, it is important to note that as of now, none of the new technologies mentioned have superseded the existing method of subcutaneous administration of insulin.

One-hundred year evolution of prandial insulin preparations: From animal pancreas extracts to rapid-acting analogs

The first insulin preparation injected in humans in 1922 was short-acting, extracted from animal pancreas, contaminated by impurities. Ever since the insulin extracted from animal pancreas has been continuously purified, until an unlimited synthesis of regular human insulin (RHI) became possible in the '80s using the recombinant-DNA (rDNA) technique. The rDNA technique then led to the designer insulins (analogs) in the early '90s. Rapid-acting insulin analogs were developed to accelerate the slow subcutaneous (sc) absorption of RHI, thus lowering the 2-h post-prandial plasma glucose (PP-PG) and risk for late hypoglycemia as comparing with RHI. The first rapid-acting analog was lispro (in 1996), soon followed by aspart and glulisine. Rapid-acting analogs are more convenient than RHI: they improve early PP-PG, and 24-h PG and A1C as long as basal insulin is also optimized; they lower the risk of late PP hypoglycemia and they allow a shorter time-interval between injection and meal. Today rapid-acting analogs are the gold standard prandial insulins. Recently, even faster analogs have become available (faster aspart, ultra-rapid lispro) or are being studied (Biochaperone lispro), making additional gains in lowering PP-PG. Rapid-acting analogs are recommended in all those with type 1 and type 2 diabetes who need prandial insulin replacement.

Effectiveness and Safety of Insulin Glulisine When Initiating Supplementary Prandial Insulin Treatment (SIT) in Insulin-Naïve Patients with Type 2 Diabetes: The Observational IGLU-SIT Study

INTRODUCTION

The IGLU-SIT study documented the effectiveness of initiating supplementary prandial insulin treatment (SIT) with insulin glulisine after failure of oral antidiabetic drugs alone in patients with type 2 diabetes (T2DM) in a real-world setting in Germany.

METHODS

The IGLU-SIT study was an open-label, prospective, multicentre, non-interventional study with an observation period of 12 ± 1 months. The primary objective was to determine the proportion of patients reaching their pre-defined glycosylated haemoglobin (HbA1c) goal at 3, 6, 9 and 12 months. Selected secondary objectives were absolute change in HbA1c, a 7-point blood glucose profile, and rate of hypoglycaemia. Data were evaluated overall and by age group (< 65, 65-74 and ≥ 75 years).

RESULTS

Overall, 215 patients with T2DM were observed in 64 centres. Baseline HbA1c was 8.3%, and mean HbA1c target was 6.8% (baseline 8.1% and target 6.9% in patients ≥ 75 years). Individual HbA1c target attainment in patients peaked at 38.9% (95% confidence interval [CI] 32.1-46.1%) after 12 months; this was 45.9% in patients aged ≥ 75 years. The mean HbA1c reduction was 1.12 ± 1.05% (p < 0.0001) with only minor differences by age group. A 7-point blood glucose profile revealed significant reductions (p < 0.0001) at all time-points. The rate of confirmed symptomatic hypoglycaemia was 2.2% (95% CI 0.7-5.1) during the 12-month follow-up; rates were increased in patients aged ≥ 75 years (7.0%; 95% CI 1.5-19.1) as were the rates of adverse events (17.8 vs. 6.1%).

CONCLUSION

Initiating SIT with insulin glulisine is an appropriate treatment option in patients whose T2DM is insufficiently controlled. Particular attention should be paid to elderly patients in whom higher attainment rates of treatment target were associated with adverse events.

TRIAL REGISTRATION

https://awbdb.bfarm.de ; Identifier: 6819; Date of registration: 23.06.2016.

Effectiveness and Safety of Switching Rapid-Acting Insulins to Insulin Glulisine in Patients with Diabetes: The Observational IGLU-S Study

INTRODUCTION

The IGLU-S study assessed the effectiveness of insulin glulisine after switching from human insulin/other rapid-acting insulin analogues in patients with type 1 diabetes (T1DM) and type 2 diabetes (T2DM) in a real-world setting in Germany.

METHODS

Open-label, prospective, multicentre, non-interventional study in Germany. The primary outcome was proportion of patients reaching pre-defined glycosylated haemoglobin A1c (HbA1c) goal at 3, 6, 9 and 12 months. Secondary outcomes included absolute changes in HbA1c, rate of hypoglycaemia and 7-point blood glucose profiles.

RESULTS

Overall, 432 (55 T1DM, 377 T2DM) patients were enrolled. Baseline HbA1c was 8.2% (T1DM) and 8.3% (T2DM); individual HbA1c targets were 6.8% and 6.9%, respectively. After insulin glulisine introduction, the proportion of patients achieving their individual HbA1c increased to 43.6% (T1DM) and 39.6% (T2DM) of patients at 12 months. At 12 months, mean HbA1c was reduced by 0.86 ± 1.03% (p < 0.0001) in T1DM and 1.01 ± 1.02 (p < 0.0001) in T2DM. The 7-point blood glucose profile showed a significant reduction in patients with T2DM (p< 0.0001) and a non-significant reduction in T1DM patients. Confirmed symptomatic hypoglycaemia was 5.7% (T1DM) and 1.6% (T2DM). There were no cases of severe hypoglycaemia.

CONCLUSION

Switching prandial insulin to insulin glulisine resulted in improved effectiveness with 43.6% of T1DM and 39.6% of T2DM patients reaching their individual pre-defined HbA1c target within 1 year. Switching was safe and was associated with a low rate of hypoglycaemia and adverse events.

TRIAL REGISTRATION

https://awbdb.bfarm.de ; Identifier: 6818; Date of registration: 23.06.2016.

Improving the treatment of patients with diabetes using insulin analogues: current findings and future directions

Introduction: The aim of insulin replacement in insulin-deficient people (type 1 diabetes, pancreatic causes of diabetes, long-standing type 2 diabetes) is to approximate the physiologic insulin action profile as closely as possible. However, short-acting human insulins start too slow and act too long, causing postprandial hyperglycemia and delayed hypoglycemia, while the insulin action profile of long-acting human insulins is too variable in duration and strength of action, leading to insufficient basal insulin covering and peak insulin levels after injection causing early nocturnal hypoglycemia. Insulin analogues were designed to overcome these shortcomings. In insulin-resistant people (type 2 diabetes), insulin analogues contribute to more efficient and safer insulin supplementation. Areas covered: In this review, we describe the unmet needs for insulin therapy, the currently available short- and long-acting insulin analogues and some considerations on cardiovascular outcomes, use in special populations, and cost-effectiveness. Finally, we discuss what is new in the field of insulin analogues. Expert opinion: The development of insulin analogues is an important step in diabetes treatment. Despite many patients meeting their glycemic targets with the newest analogues, hypoglycemic episodes remain a major problem. More physiologic insulin regimens, with glucose-sensitive or organ-targeting insulin analogues may be the answer to these issues.

Pharmacokinetics, tissue distribution and excretion of a novel long-acting human insulin analogue - recombinant insulin LysArg in rats

As a novel long-acting recombinant human insulin analogue, it is necessary to carry out the preclinical research for insulin LysArg. The purpose of this study was to characterise the pharmacokinetic, tissue distribution and excretion of insulin LysArg and provide a reference for its development. Three methods were used to measure the content of insulin LysArg in biological samples after a single subcutaneous administration in rats, including radioassay, radioassay after precipitation with TCA and separation by HPLC. After Subcutaneous administration of recombinant insulin LysArg 1, 2, 4 U/kg in rats, it showed both C_max and AUC_0-t were positively correlated with the dose. In the meanwhile, after a single subcutaneous administration of recombinant insulin LysArg at 2 U/kg in rats, the amount of radioactivity in most organs was highest at 1.5 h and then decreased gradually, no accumulation was found. The highest level of insulin LysArg was observed in the kidney. Like other macromolecules, insulin LysArg was mainly excreted from urine. The study fully illustrated the pharmacokinetic pattern of insulin LysArg, provided valuable informations to support its further development about safety and toxicology.

The quaternary structure of insulin glargine and glulisine under formulation conditions

The quaternary structures of insulin glargine and glulisine under formulation conditions and upon dilution using placebo or water were investigated using synchrotron small-angle X-ray scattering. Our results revealed that insulin glulisine in Apidra® is predominantly hexameric in solution with significant fractions of dodecamers and monomers. Upon dilution with placebo, this equilibrium shifts towards monomers. Insulin glargine in Lantus® and Toujeo® is present in a stable hexamer/dimer equilibrium, which is hardly affected by dilution with water down to 1 mg/ml insulin concentration. The results provide exclusive insight into the quaternary structure and thus the association/dissociation properties of the two insulin analogues in marketed formulations.

A Review of Basal-Bolus Therapy Using Insulin Glargine and Insulin Lispro in the Management of Diabetes Mellitus

Basal-bolus therapy (BBT) refers to the combination of a long-acting basal insulin with a rapid-acting insulin at mealtimes. Basal insulin glargine 100 U/mL and prandial insulin lispro have been available for many years and there is a substantial evidence base to support the efficacy and safety of these agents when they are used in BBT or basal-plus therapy for patients with type 1 or type 2 diabetes mellitus (T1DM, T2DM). With the growing availability of alternative insulins for use in such regimens, it seems timely to review the data regarding BBT with insulin glargine 100 U/mL and insulin lispro. In patients with T1DM, BBT with insulin glargine plus insulin lispro provides similar or better glycemic control and leads to less nocturnal hypoglycemia compared to BBT using human insulin as the basal and/or prandial component, and generally provides similar glycemic control and rates of severe hypoglycemia to those achieved with insulin lispro administered by continuous subcutaneous insulin infusion (CSII). Studies evaluating BBT with insulin glargine plus insulin lispro in patients with T2DM also demonstrate the efficacy and safety of these insulins. Available data suggest that BBT with insulin glargine and insulin lispro provides similar levels of efficacy and safety in pediatric and adult populations with T1DM and in adult patients and those aged more than 65 years with T2DM. These insulin preparations also appear to be safe and effective for controlling T2DM in people of different ethnicities and in patients with T1DM or T2DM and comorbidities.

FUNDING

Eli Lilly and Company.

Rapid-Acting and Human Insulins: Hexamer Dissociation Kinetics upon Dilution of the Pharmaceutical Formulation

Purpose

Comparison of the dissociation kinetics of rapid-acting insulins lispro, aspart, glulisine and human insulin under physiologically relevant conditions.

Methods

Dissociation kinetics after dilution were monitored directly in terms of the average molecular mass using combined static and dynamic light scattering. Changes in tertiary structure were detected by near-UV circular dichroism.

Results

Glulisine forms compact hexamers in formulation even in the absence of Zn²⁺. Upon severe dilution, these rapidly dissociate into monomers in less than 10 s. In contrast, in formulations of lispro and aspart, the presence of Zn²⁺ and phenolic compounds is essential for formation of compact R6 hexamers. These slowly dissociate in times ranging from seconds to one hour depending on the concentration of phenolic additives. The disadvantage of the long dissociation times of lispro and aspart can be diminished by a rapid depletion of the concentration of phenolic additives independent of the insulin dilution. This is especially important in conditions similar to those after subcutaneous injection, where only minor dilution of the insulins occurs.

Conclusion

Knowledge of the diverging dissociation mechanisms of lispro and aspart compared to glulisine will be helpful for optimizing formulation conditions of rapid-acting insulins.

Electronic supplementary material

The online version of this article (doi:10.1007/s11095-017-2233-0) contains supplementary material, which is available to authorized users.

Insulin analogues in type 1 diabetes mellitus: getting better all the time

The treatment of type 1 diabetes mellitus consists of external replacement of the functions of β cells in an attempt to achieve blood levels of glucose as close to the normal range as possible. This approach means that glucose sensing needs to be replaced and levels of insulin need to mimic physiological insulin-action profiles, including basal coverage and changes around meals. Training and educating patients are crucial for the achievement of good glycaemic control, but having insulin preparations with action profiles that provide stable basal insulin coverage and appropriate mealtime insulin peaks helps people with type 1 diabetes mellitus to live active lives without sacrificing tight glycaemic control. Insulin analogues enable patients to achieve this goal, as some have fast action profiles, and some have very slow action profiles, which gives people with type 1 diabetes mellitus the tools to achieve dynamic insulin-action profiles that enable tight glycaemic control with a risk of hypoglycaemia that is lower than that with human short-acting and long-acting insulins. This Review discusses the established and novel insulin analogues that are used to treat patients with type 1 diabetes mellitus and provides insights into the future development of insulin analogues.

Insulin glulisine for continuous subcutaneous insulin infusion in pediatric type 1 diabetes

We evaluated the efficacy and safety of insulin glulisine (GLU) used for continuous s.c. insulin infusion (CSII) in 20 children with type 1 diabetes after 1 year of GLU treatment. There were no significant differences in mean plasma glucose before breakfast and before dinner between before and after using GLU, but the levels after breakfast and after dinner significantly improved, from 192.5 ± 31.7 to 162.0 ± 27.3 mg/dL for breakfast, and from 191.1 ± 33.3 to 161.1 ± 24.5 mg/dL for dinner (P < 0.01). Mean hemoglobin A1c significantly decreased (from 8.0 ± 0.8 to 7.7 ± 0.8%, P < 0.05), and the mean frequency of hypoglycemia significantly reduced after using GLU (from 8.3 ± 4.9 to 6.0 ± 3.4/month, P < 0.05). In conclusion, the use of GLU rather than other rapid-acting analogues for CSII might be an effective treatment option in children with type 1 diabetes.

Insulin Aspart in the Management of Diabetes Mellitus: 15 Years of Clinical Experience

Limiting excessive postprandial glucose excursions is an important component of good overall glycemic control in diabetes mellitus. Pharmacokinetic studies have shown that insulin aspart, which is structurally identical to regular human insulin except for the replacement of a single proline amino acid with an aspartic acid residue, has a more physiologic time-action profile (i.e., reaches a higher peak and reaches that peak sooner) than regular human insulin. As expected with this improved pharmacokinetic profile, insulin aspart demonstrates a greater glucose-lowering effect compared with regular human insulin. Numerous randomized controlled trials and a meta-analysis have also demonstrated improved postprandial control with insulin aspart compared with regular human insulin in patients with type 1 or type 2 diabetes, as well as efficacy and safety in children, pregnant patients, hospitalized patients, and patients using continuous subcutaneous insulin infusion. Studies have demonstrated that step-wise addition of insulin aspart is a viable intensification option for patients with type 2 diabetes failing on basal insulin. Insulin aspart has shown a good safety profile, with no evidence of increased receptor binding, mitogenicity, stimulation of anti-insulin antibodies, or hypoglycemia compared with regular human insulin. In one meta-analysis, there was evidence of a lower rate of nocturnal hypoglycemia compared with regular human insulin and, in a trial that specifically included patients with a history of recurrent hypoglycemia, a significantly lower rate of severe hypoglycemic episodes. The next generation of insulin aspart (faster-acting insulin aspart) is being developed with a view to further improving on these pharmacokinetic/pharmacodynamic properties.

Effects of rapid-acting insulin analogues insulin glulisine and insulin aspart on postprandial glycemic excursion with single bout of exercise in patients with type 2 diabetes

The analogue insulin glulisine (Glu) shows both more rapid onset and shorter duration of action compared with the other rapid-acting insulin analogues. The current study investigates these properties in regard to the occurrence of hypoglycemia related to exercise. A randomized, single-center, open-label, crossover study was conducted in 12 hospitalized type 2 diabetes patients (all male, mean ± SD age of 51.9 ± 11.3 years; BMI: 25.5 ± 3.9 kg/m2; HbA1c: 11.2 ± 2.4 %). Glu or insulin aspart (Asp) was subcutaneously administered just before breakfast. Insulin dosage was determined as the usual dose of pre-prandial rapid-acting insulin for patients treated with insulin therapy or as 0.1 unit/kg for patients treated with oral anti-hyperglycemic agents. Sixty min after the start of eating, the patients began aerobic exercise on a bicycle ergometer for 30 min at 50% of maximum heart rate. Hypoglycemic episodes (plasma glucose level < 70 mg/dL with or without symptoms) were observed more frequently in Asp group (p < 0.05). Post-exercise plasma glucose levels at 90, 120, and 150 min were significantly lower in Asp group (p < 0.05). In patients with BMI < 25 kg/m2 (n = 6), post-exercise blood glucose levels were significantly lower in Asp group (p < 0.05), while in patients with BMI ≥ 25 kg/m2 (n = 6) the difference was not significant. Glu may therefore be a suitable choice of rapid-acting insulin for patients with type 2 diabetes who are at high risk of post-exercise hypoglycemia.

Pharmacokinetics of insulin lispro in type 2 diabetes during closed-loop insulin delivery

Insulin pharmacokinetics is not well understood during continuous subcutaneous insulin infusion in type 2 diabetes (T2D). We analyzed data collected in 11 subjects with T2D [6 male, 9 white European and two of Indian ethnicity; age 59.7(12.1) years, BMI 30.1(3.9) kg/m(2), fasting C-peptide 1002.2(365.8) pmol/l, fasting plasma glucose 9.6(2.2) mmol/l, diabetes duration 8.0(6.2) years and HbA1c 8.3(0.8)%; mean(SD)] who underwent a 24-h study investigating closed-loop insulin delivery at the Wellcome Trust Clinical Research Facility, Cambridge, UK. Subcutaneous delivery of insulin lispro was modulated every 15 min according to a model predictive control algorithm. Two complementary insulin assays facilitated discrimination between exogenous (lispro) and endogenous plasma insulin concentrations measured every 15-60 min. Lispro pharmacokinetics was represented by a linear two-compartment model whilst parameters were estimated using a Bayesian approach applying a closed-form model solution. The time-to-peak of lispro absorption (t(max)) was 109.6 (75.5-120.5) min [median (interquartile range)] and the metabolic clearance rate (MCR(I)) 1.26 (0.87-1.56)×10(-2) l/kg/min. MCR(I) was negatively correlated with fasting C-peptide (r(s)=-0.84; P=.001) and with fasting plasma insulin concentration (r(s)=-0.79; P=.004). In conclusion, compartmental modelling adequately represents lispro kinetics during continuous subcutaneous insulin infusion in T2D. Fasting plasma C-peptide or fasting insulin may be predictive of lispro metabolic clearance rate in T2D but further investigations are warranted.

Evolution of insulin: from human to analog

The development of insulin analogs has made improved treatment of type 2 diabetes possible. In this article, structural alterations, pharmacokinetics and pharmacodynamics, clinical end points, and safety issues are reviewed for the currently available basal insulins, rapid-acting insulins, and premixes. The flatter activity profiles of insulin glargine and insulin detemir translate into good clinical efficacy with a lower risk of hypoglycemia relative to neutral protamine Hagedorn insulin. Weight gain is consistently lower with insulin detemir than with neutral protamine Hagedorn insulin. Insulin degludec, licensed in Europe and Japan but not yet in the United States, has a mean half-life of 25.4 hours, a duration of action of >42 hours, and low variability. In trials in type 2 diabetes, rates of nocturnal hypoglycemia were lower with insulin degludec than with insulin glargine, and more flexible; once-daily dose timing was shown to be possible. Insulin lispro, insulin aspart, and insulin glulisine are rapidly absorbed after injection and thus provide better coverage of the post-prandial glucose surge compared with human insulin. Trials and meta-analyses show that reductions in glycated hemoglobin are similar and control of postprandial glucose is better with the rapid-acting analogs versus human insulin. Convenience is greater for patients because the analogs can be injected just before a meal. In premix or biphasic insulins, a proportion of the rapid-acting analog is protaminated, providing both rapid-acting and intermediate-acting components in one formulation, thus reducing the number of injections required. Alterations to human insulin have resulted in improvements in safety, efficacy, tolerability, and convenience for patients.

Advantage of insulin glulisine over regular insulin in patients with type 2 diabetes and severe renal insufficiency

OBJECTIVES

To compare the efficacy and safety of insulin glulisine over regular insulin in patients with type 2 diabetes and severe renal insufficiency.

SUBJECTS

Our study included 18 patients with type 2 diabetes and a mean (range) estimated glomerular filtration rate of 13.2 mL/minute/1.73 m(2) (5.8-27.6), which corresponds to stage 4-5 chronic kidney disease.

DESIGN

After titration of doses, regular insulin was administered thrice daily on Day 1, along with continuous glucose monitoring for 24 h starting at 7 am. Exactly equal doses of insulin glulisine were administered on Day 2. Area under the curve (AUC) for blood glucose level variation after breakfast (AUC-B 0-4), lunch (AUC-L 0-6), and dinner (AUC-D 0-6) were evaluated.

RESULTS

AUC-B 0-4 and AUC-D 0-6 were significantly lower with insulin glulisine than with regular insulin (AUC-B 0-4: 3.3 ± 4.7 vs. 6.2 ± 5.4 × 10(2) mmol/L·minute, respectively, P = .028; AUC-D 0-6: 1.8 ± 7.3 vs. 6.5 ± 6.2 × 10(2) mmol/L·minute, respectively, P = .023). In contrast, AUC-L 0-6 was higher with insulin glulisine than with regular insulin (AUC-L 0-6: 7.6 ± 6.4 vs. 4.2 ± 8.7 × 10(2) mmol/L·minute, respectively, P = .099), suggesting a prolonged hypoglycemic action of regular insulin after lunch.

CONCLUSIONS

Insulin glulisine effectively suppressed postprandial hyperglycemia, whereas regular insulin caused a prolonged hypoglycemic action. These findings support the effectiveness and safety of insulin glulisine in patients with type 2 diabetes and severe renal insufficiency.

Efficacy and safety of switching to insulin glulisine from other rapid-acting insulin analogs in children with type 1 diabetes

We investigated the efficacy and safety of switching to insulin glulisine (GLU) from other rapid-acting insulin analogs (Ra) in children with type 1 diabetes treated with multiple daily injections of insulin or continuous subcutaneous insulin infusion. A total of 26 children with type 1 diabetes were included. Ra in all of these patients was changed to GLU, and they were observed for a 6-month period after having previously finished treatment with other Ra. The mean glycated hemoglobin value decreased from 7.6 ± 1.0 to 7.4 ± 0.9% (P = 0.0034), and mean plasma glucose values after breakfast and supper also improved from 183 ± 50 to 153 ± 32 mg/dL (P = 0.0035), and from 203 ± 29 to 164 ± 23 mg/dL (P < 0.0001), respectively. Furthermore, the mean frequency of hypoglycemia was reduced from 7 ± 6 to 4 ± 4/month (P = 0.0004), while insulin doses and obesity degree were stable with statistically non-significant differences. In conclusion, switching to GLU might be a good treatment option for improving glycemic control in children with type 1 diabetes.

Comparison of daily glucose excursion by continuous glucose monitoring between type 2 diabetic patients receiving preprandial insulin aspart or postprandial insulin glulisine

Insulin glulisine (Glu) is a rapidly-acting insulin analog with a faster onset of action than the other insulin analogs of its class, which are insulin aspart (Asp) and insulin lispro (Lisp). While insulin Glu is usually injected just before meals, postprandial injection may help to avoid unexpected postprandial hypoglycemia or hyperglycemia by adjusting the insulin dosage according to food intake. However, the effect of postprandial insulin Glu on the glucose profile has not been evaluated. The aim of this study was to compare daily glucose excursion by continuous glucose monitoring (CGM) between multiple daily doses of preprandial insulin Asp or postprandial insulin Glu. In a randomized cross-over trial, we performed CGM to evaluate the 48-hour glucose profile during treatment with the same dosage of insulin Asp just before each meal in 12 hospitalized patients with type 2 diabetes. Patients also received the same dosage of long-acting insulin glargine at bedtime. The average glucose level, standard deviation of the glucose level, mean amplitude of glucose excursion, and daily glucose profile did not differ between preprandial Asp and postprandial Glu. The incidence of hypoglycemic episodes (glucose level<70 mg/dL with or without symptoms) and the area under the curve of glucose<70 mg/dL also did not differ between the two insulin regimens. Multiple daily injections of preprandial Asp and postprandial Glu achieved the same daily glucose excursion profile. Postprandial injection of Glu may provide greater flexibility for patients who require insulin therapy.

Peptide therapeutics: it's all in the delivery

Recent work has demonstrated that the route of administration affects the pharmacokinetics and biological activity of peptides. For example, the physiological profile of insulin consists of basal and prandial components with a small-scale oscillatory element. Insulin is used more efficiently when the pharmacokinetic profile mimics features of physiological release. Noninvasive administration of insulin by oral, transdermal, nasal and pulmonary routes resembles the relatively sharp peak and short duration of exposure of prandial release. The route of administration per se, can affect the response by avoiding first-pass metabolism or perhaps altering the timing in which the peptide reaches different sets of receptors. GLP-I delivered by injection and inhalation produces different side effect profiles. Nonclinical studies on two potential treatments for obesity, oxyntomodulin and PYY 3-36, are also presented to illustrate the relationship between exposure and effect as functions of route of administration.

The pharmacokinetics and pharmacodynamics of rapid-acting insulin analogues and their clinical consequences

Postprandial glucose excursions can inhibit achievement of good glycaemic control, and possibly have a specific effect on the risk of vascular comorbidities. Rapid-acting analogues control these excursions better than human insulin because their pharmacokinetic/pharmacodynamic (PK/PD) profile is closer to that of meal-time endogenous insulin secretion. Review of the findings of PK/PD studies and clinical trials suggests that the three marketed rapid-acting analogues--insulin lispro, insulin aspart and insulin glulisine--are equally efficacious and safe. In comparison with human insulin when using the same basal insulin, they provide comparable glycaemic control with a reduced risk of hypoglycaemia, although the combination of rapid-acting and basal analogues reduces glycated haemoglobin (HbA(1c)) more than human meal-time insulin combined with neutral protamine Hagedorn (NPH) insulin. Some studies have suggested that insulin glulisine has a slightly faster onset of action compared with insulin lispro or insulin aspart, but this has not been translated into demonstrable clinical benefit. Treatment satisfaction in patients with diabetes has been higher when therapy with a rapid-acting analogue is used instead of human insulin, perhaps due to differences in advised timing of injection. The largest benefits in efficacy, hypoglycaemia incidence, treatment satisfaction and quality of life have occurred when patients receive an all-analogue meal-time plus basal regimen as compared with an all-human insulin regimen. No new safety issues have been identified with the marketed rapid-acting analogues, and their insulin-like growth factor 1 receptor affinity and mitogenic activity are comparable to human insulin.

Evolution of insulin development: focus on key parameters

INTRODUCTION

Although insulin products and treatment strategies have improved significantly, clinical challenges still exist. Meeting glycemic goals while minimizing glucose variability and hypoglycemia is of utmost importance when considering existing insulin therapies and designing investigational insulin treatments.

METHODS

A PubMed search identified relevant, peer-reviewed articles related to the evolution of insulin development for this nonsystematic review. Search terms included "animal insulin," "synthetic insulin," "regular human insulin," "insulin lispro," "insulin aspart," "insulin glulisine," "insulin glargine," "insulin detemir," "insulin degludec," "biphasic human insulin," "insulin premixes," "ultra-long acting," "oral insulin," and "inhaled insulin."

RESULTS

While the discovery of animal insulin significantly decreased mortality rates from diabetes, issues with availability and large variability between batches led to difficulty in determining proper doses and, subsequently, challenges in achieving glycemic control and avoiding hypoglycemia. The development of synthetic insulin created a more readily available supply, but hypoglycemia still persisted. Recombinant DNA technology solved insulin production problems and allowed for the development of better retarding agents, but pharmacokinetic/pharmacodynamic profiles still did not mimic natural insulin. Insulin premixes offered improved glycemic control, decreased intrapatient variability versus self-mixing, and required fewer injections per day; however, patient adherence remained a problem due to the need to inject 30-60 minutes before a meal for optimal control. This prompted the development of rapid-acting insulin analogs that could be injected right before a meal and long-acting insulin analogs with flatter time-action profiles.

CONCLUSION

Despite advances in insulin development, a need to provide more physiologic basal insulin coverage and reduce hypoglycemic risk in patients with diabetes remains. Newer insulin analogs and more convenient routes of insulin delivery have shown promising safety and efficacy results. Many patients with diabetes have not reached glycemic goals on currently available insulins. Additional studies are necessary to tailor optimal insulin delivery strategies to specific subsets of diabetes patients.