Pharmacokinetics and pharmacodynamics of insulin aspart, a rapid-acting analog of human insulin, in healthy Japanese volunteers

In Silico Evaluation of the Medtronic 780G System While Using the GS3 and Its Calibration-Free Successor, the G4S Sensor

In silico simulation studies using 5807 virtual patients with insulin dependent diabetes have been conducted to estimate the risk and efficacy with the closed-loop 780G pump when switching between Medtronic Guardian Sensor 3 (GS3) and Medtronic Guardian 4 Sensor (G4S), next generation calibration free glucose sensor. To demonstrate by utilizing a case study that captures the merits of in silico studies with single hormone insulin dependent virtual patients that include variability in pharmacokinetics/pharmacodynamics, age, gender, insulin sensitivity and BMIs. Also, to show that in silico studies can uniquely isolate the effect of a single variable on clinical outcomes. Simulation studies results were compared to clinical and commercial data and were separated by age groups and pump settings. The commercial data, the clinical study data and the simulation studies predicted that switching between GS3 to G4S will introduce a change in glucose average, percentage time between 70 and 180 mg/dL, and percentage time below 70 mg/dL of: 5.2, 3.4, and 3.1 mg/dL, - 1.1, 0.2, and - 1.1%, and - 0.6, - 1.0, and - 0.3%, respectively. We demonstrated that our simulation studies were able to predict the difference in glycemic outcomes when switching between different sensors in real world setting, better than a small clinical controlled study. As predicted, switching between GS3 and G4S sensors with the 780G system does not introduce clinical risk and maintain the clinical outcomes of the sensor. We demonstrated the ability of insulin dependent diabetes virtual patients to predict clinical outcomes and to augment or even replace some small clinical studies.

Optimization of pig models for translation of subcutaneous pharmacokinetics of therapeutic proteins: Liraglutide, insulin aspart and insulin detemir

Prediction of human pharmacokinetics (PK) from data obtained in animal studies is essential in drug development. Here, we present a thorough examination of how to achieve good pharmacokinetic data from the pig model for translational purposes by using single-species allometric scaling for selected therapeutic proteins: liraglutide, insulin aspart and insulin detemir. The predictions were based on non-compartmental analysis of intravenous and subcutaneous PK data obtained from two injection regions (neck, thigh) in two pig breeds, domestic pig and Göttingen Minipig, that were compared with PK parameters reported in humans. The effects of pig breed, injection site and injection depth (insulin aspart only) on the PK of these proteins were also assessed. Results show that the prediction error for human PK was within two-fold for most PK parameters in both pig breeds. Furthermore, pig breed significantly influenced the plasma half-life and mean absorption time (MAT), both being longer in Göttingen Minipigs compared to domestic pigs (P <0.01). In both breeds, thigh vs neck dosing was associated with a higher dose-normalized maximum plasma concentration and area under the curve as well as shorter MAT and plasma half-life (P <0.01). Finally, more superficial injections resulted in faster absorption, higher C_max/dose and bioavailability of insulin aspart (P <0.05, 3.0 vs 5.0 mm injection depth). In conclusion, pig breed and injection region affected the PK of liraglutide, insulin aspart and insulin detemir and reliable predictions of human PK were demonstrated when applying single-species allometric scaling with the pig as a pre-clinical animal model.

Successful treatment with artificial pancreas for a patient who attempted suicide using a high-dose insulin s.c. injection

Background

Artificial pancreas is usually used to manage hyperglycemia. We controlled prolonged hypoglycemia induced by insulin overdose using artificial pancreas.

Case Presentation

A 56‐year‐old female patient with type 2 diabetes mellitus was admitted to the emergency department after overdosing on 1,800 units each of insulin aspart and insulin degludec. She had also ingested 2 weeks of anti‐anxiety medication. When the patient arrived at the hospital, her blood glucose level was 30 mg/dL and she was in a coma. Artificial pancreas (STG‐55; Nikkiso, Tokyo, Japan) was used to control blood glucose levels because we were unable to predict the duration or degree of hypoglycemia. Blood glucose levels were safely controlled without the development of hypo‐ or hyperglycemia. Finally, the patient was discharged without any complications on day 7.

Conclusion

The STG‐55 artificial pancreas was very useful and convenient for controlling blood glucose levels in our insulin overdose patient.

Sensor-Augmented Pump-Based Customized Mathematical Model for Type 1 Diabetes

BACKGROUND

Simulations using mathematical models are important for studying, developing, and improving therapies for people with type 1 diabetes.

METHODS

The Medtronic CareLink^® database was used to create virtual patients with a variety of inter-insulin sensitivities, meal absorption rates, pharmacokinetics, age, and gender. In addition, intra-insulin sensitivities of the virtual patients change over a 24-h cycle.

RESULTS

A total of 2087 virtual patients were developed. The time percentage between 70 and 180 mg/dL of the CareLink uploads and the simulated virtual patients was 72.4% (18.6) and 74.1% (16.9), respectively. The time percentage <70 mg/dL of the real continuous glucose monitoring from CareLink uploads and the simulated virtual patients was 1% (2.4) and 1.7% (4.1), respectively. A simulation study with the virtual patients predicted the glycemic distribution after 2 h of insulin suspension as reported in the ASPIRE (Automation to Simulate Pancreatic Insulin Response) clinical trial. The 3 months outcomes of Medtronic's hybrid closed-loop 670G system pivotal trial were also predicted in a simulation study. The time percentage <70 mg/dL was 3.4% and 3.1%, and the time percentage between 71 and 180 mg/dL was 73.8% and 77.7% for 93 pivotal study adults (>18 years) and 90 adult (>28 years) virtual patients, respectively.

CONCLUSION

The Medtronic CareLink database was utilized to generate a large number of virtual patients with a variety of insulin sensitivities, pharmacokinetics, and meal absorption rates. This new simulation model can be potentially used to evaluate and prognosticate the outcomes of studies of artificial pancreas algorithms and systems.

Fast-acting insulin aspart in Japanese patients with type 1 diabetes: Faster onset, higher early exposure and greater early glucose-lowering effect relative to insulin aspart

INTRODUCTION

Fast-acting insulin aspart (faster aspart) is insulin aspart (IAsp) in a new formulation with two added excipients (niacinamide and L-arginine) in order to obtain accelerated absorption after subcutaneous dosing. The present study compared the pharmacokinetic/pharmacodynamic characteristics of faster aspart vs IAsp in Japanese patients with type 1 diabetes.

MATERIALS AND METHODS

In a randomized, double-blind, cross-over design, 43 participants were given faster aspart and IAsp (0.2 U/kg single dose) at two separate dosing visits. Frequent pharmacokinetic blood sampling was carried out, and pharmacodynamics were assessed using an automated euglycemic clamp lasting for a maximum of 12 h after dosing (target 5.5 mmol/L).

RESULTS

Faster aspart showed onset of appearance approximately twice-as-fast vs IAsp (least squares means: 3.0 vs 7.1 min; estimated treatment difference -4.1 min, 95% confidence interval [CI]: -5.0, -3.2; P < 0.001) and onset of action occurring approximately 5 min earlier (20.2 vs 25.5 min; estimated treatment difference -5.3 min, 95% CI: -8.4, -2.2; P = 0.001). Within the first 30 min post-dose, both exposure (area under the curve [AUC]IAsp,0-30 min ) and glucose-lowering effect (AUCGIR,0-30 min ) were approximately twofold greater for faster aspart vs IAsp (P < 0.001 and P = 0.002, respectively). Bioavailability of faster aspart was similar to IAsp (AUCIAsp,0-t ; estimated treatment ratio 0.99, 90% CI: 0.96-1.02), whereas the total glucose-lowering effect (AUCGIR,0-t ) was slightly lower for faster aspart vs IAsp (estimated treatment ratio 0.93, 95% CI: 0.87-0.99, P = 0.020).

CONCLUSIONS

Faster aspart showed faster onset, higher early exposure and a greater early glucose-lowering effect relative to IAsp in Japanese patients with type 1 diabetes, in accordance with previous findings in Caucasian type 1 diabetes patients.

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.

Characterization of Streptozotocin-induced Diabetic Rats and Pharmacodynamics of Insulin Formulations

Morphological and functional changes of rat pancreatic islets caused by administration of streptozotocin (STZ) and the bioavailability of insulin formulations administered to STZ-induced diabetic rats with fasting (12 h) or non-fasting were investigated. Islets isolated from normal rats maintained a good three-dimensional structure and the islet yield was 962.5+/-86.5 islet equivalent number (IEQ, islets converted to an average diameter of 150 microm). In the diabetic group (>500 mg/ml blood glucose), the islet yield was only 44.4+/-8.3 IEQ and the islet was severely damaged. The minimum reduction of blood glucose of each formulation, such as insulin solution, microcrystal, and insulin microcrystal capsule, was shown to be 11.3, 11.0, and 16.3 mg/dl, respectively, at 6 h in fasting with diabetic rats. These results indicated that the administration of insulin formulations to the fasting groups increased the severe hypoglycemic effect of insulin action more than in non-fasting diabetic rats. The diabetic rat with fasting has a regulatory disorder in maintaining the blood glucose level. Accordingly, the validity of pharmacological availability as an optimal modeling of insulin formulations is best in non-fasting STZ-induced diabetic rats.

Pharmacokinetic and pharmacodynamic responses of insulin degludec in African American, white, and Hispanic/Latino patients with type 2 diabetes mellitus

BACKGROUND

Pharmacokinetic and pharmacodynamic profiles of exogenous insulin may be affected by intrinsic factors, such as age, ethnicity/race, and hepatic and renal function. Insulin degludec (IDeg) is a basal insulin with an ultralong duration of action and a flat and stable glucose-lowering effect profile.

OBJECTIVE

The purpose of this study was to investigate whether the pharmacokinetic and pharmacodynamic responses to IDeg at steady state vary according to patient race/ethnicity.

METHODS

This randomized, single-center, double-blind, 2-period crossover trial investigated responses to IDeg in 59 patients with type 2 diabetes mellitus from 3 groups: African American, Hispanic/Latino, and white. Patients were allocated randomly to a sequence of 2 treatment periods, separated by a 7- to 21-day washout period, with once-daily IDeg or insulin detemir dosing for 6 days at a predefined fixed dose level (0.6 U/kg). Differences in pharmacokinetic and pharmacodynamic variables among groups were analyzed using an ANOVA with treatment period, an interaction between race/ethnicity, and treatment as fixed factors, subject as a random effect, and residual variance, depending on treatment.

RESULTS

Total exposure to IDeg during one dosing interval at steady state (AUCIDeg,τ,SS) was similar among the racial/ethnic groups (ratio [95% CI]: African American vs white, 1.10 [0.91-1.31]; African American vs Hispanic/Latino, 1.13 [0.95-1.34]; and Hispanic/Latino vs white, 0.97 [0.82-1.16]). The total glucose-lowering effect of IDeg (AUCGIR,τ,SS) was also similar among the groups, with no statistically significant difference in pairwise comparisons (1940, 1735, and 2286 mg/kg in African American, white, and Hispanic/Latino patients, respectively). Steady state was reached in all groups after 2 to 3 days of dosing. In all groups, both exposure and glucose-lowering effect for IDeg were evenly distributed between the first and second 12 hours of the 24-hour dosing interval at steady state (mean AUCIDeg,0-12h,SS/AUCIDeg,τ,SS = 53%-54%; AUCGIR,0--12h,SS/AUCGIR,τ,SS = 47%-52%).

CONCLUSION

The similar pharmacokinetic and pharmacodynamic responses to IDeg in 3 racial/ethnic groups of patients with type 2 diabetes mellitus suggest that the flat, stable, and ultralong pharmacokinetic and pharmacodynamic profiles of IDeg are preserved irrespective of race/ethnicity. Although insulin doses must be adjusted on an individual basis, similar pharmacokinetic and pharmacodynamic responses to IDeg are observed in patients with differing race/ethnicity.

A comparison of pharmacokinetics and pharmacodynamics of insulin aspart, biphasic insulin aspart 70, biphasic insulin aspart 50, and human insulin: a randomized, quadruple crossover study

BACKGROUND

We compared the pharmacokinetic and pharmacodynamic profiles of insulin aspart, biphasic insulin aspart 70 (BIAsp70) and 50 (BIAsp50) (containing 70% and 50% rapid-acting insulin aspart, respectively), and soluble human insulin under experimental conditions.

SUBJECTS AND METHODS

In this randomized, four-period crossover study, 19 type 1 diabetes patients received subcutaneous injections of identical doses (0.2 U/kg) of insulin aspart, BIAsp70, or BIAsp50 immediately before a standardized meal or human insulin 30 min before meal. Plasma glucose and serum insulin were measured for 12 h postprandially.

RESULTS

The pharmacokinetic and pharmacodynamic profiles of human insulin differed from those of insulin aspart, BIAsp70, and BIAsp50. The three different aspart preparations had easily distinguishable features with regard to onset and duration of action. Insulin aspart preparations were, on average, absorbed twice as fast as human insulin. In the initial phases (0-4 h and 0-6 h), the insulin area under the concentration-time curve (AUC(ins)) was significantly higher during insulin aspart treatment compared with the others, whereas insulin aspart had a significantly lower AUC(ins) over the last 6 h (P<0.05). BIAsp70 and BIAsp50 provided insulin coverage comparable to that of human insulin over the last 6 h. Insulin aspart had the most pronounced onset of action and the shortest duration. Comparing with insulin aspart and BIAsp70, BIAsp50 revealed a closer treatment ratio to human insulin on pharmacodynamic end points.

CONCLUSIONS

BIAsp70 and BIAsp50 injected immediately before a meal are at least as effective as human insulin injected 30 min earlier in controlling postprandial glycemic excursions. BIAsp50 showed the greatest similarity to human insulin with regard to pharmacokinetic and pharmacodynamic profiles.

Pharmacokinetics and pharmacodynamics of insulin analogs in special populations with type 2 diabetes mellitus

Introduction

The goal of insulin therapy in patients with either type 1 diabetes mellitus (T1DM) or type 2 diabetes mellitus (T2DM) is to match as closely as possible normal physiologic insulin secretion to control fasting and postprandial plasma glucose. Modifications of the insulin molecule have resulted in two long-acting insulin analogs (glargine and detemir) and three rapid-acting insulins (aspart, lispro, and glulisine) with improved pharmacokinetic/pharmacodynamic (PK/PD) profiles. These agents can be used together in basal-bolus therapy to more closely mimic physiologic insulin secretion patterns.

Methods

This study reviews effects of the multiple demographic and clinical parameters in the insulin analogs glargine, detemir, lispro, aspart, and glulisine in patients with T2DM. A search was conducted on PubMed for each major topic considered (effects of injection site, age, race/ethnicity, obesity, renal or hepatic dysfunction, pregnancy, exercise, drug interactions) using the topic words and name of each type of insulin analog. Information was also obtained from the prescribing information for each insulin analog.

Results

The PK/PD profiles for insulin analogs may be influenced by many variables including age, weight, and hepatic and renal function. However, these variables do not have equivalent effects on all long-acting or rapid-acting insulin analogs.

Conclusion

Rapid-acting and long-acting insulin analogs represent major advances in treatment for patients with T2DM who require insulin therapy. However, there are potentially important PK and PD differences between the two long-acting agents and among the three rapid-acting insulin analogs, which should be considered when designing treatment regimens for special patient groups.

Comparison of effects of insulin aspart three times a day versus insulin detemir once a day on oxidative stress in patients with type 2 diabetes

The main purpose of this study was to investigate whether treatment with long-acting insulin once a day or short-acting insulin three times before each meal daily has a stronger antioxidative effect in patients with type 2 diabetes. These patients had not been treated previously with insulin and were hospitalized for initiation of glycemic control by insulin injection. The patients (n=43) were assigned consecutively and alternately to a group treated with insulin aspart injection three times daily just before each meal and a group treated with insulin detemir injection once daily before bedtime. The results showed that insulin aspart three times a day produced a greater improvement in plasma glucose, and particularly in mean postprandial plasma glucose, compared with insulin detemir once a day (p = 0.0006 for comparison of changes between the two insulin treatments). The amount of insulin needed to approach the target levels of plasma glucose was larger in the insulin aspart group (26.0 ± 10.7 U/day vs. 13.7 ± 4.9 U/day; p < 0.0001). However, only insulin detemir significantly decreased oxidative stress evaluated based on the level of urinary 8-iso-prostaglandin F2α (p = 0.0079), although the mechanisms are not fully evident.

Pharmacokinetics following continuous subcutaneous insulin infusion of insulin aspart with or without initial subcutaneous bolus

AIM

To evaluate time to steady state insulin concentration (C(ss)) following continuous subcutaneous insulin infusion (CSII) of insulin aspart (IAsp) with or without an initial s.c. bolus.

METHODS

In random order 10 healthy volunteers were given a basal insulin infusion rate (0.5 U/h) for 8 h with or without an initial s.c. bolus (1.4 U). Serum IAsp was measured until 3 h after infusion was stopped.

RESULTS

An overshoot of IAsp was seen before C(ss) was achieved following an initial bolus of insulin as compared to no bolus. The apparent half-life (t((1/2))) with or without bolus did not differ (p = 0.15). Time to steady state (T(ss)) was evaluated in two ways: (1) T(ss) defined as the first point within an interval of C(ss)+/- 2 x CV was 233 vs. 166 min with and without a bolus respectively (p = 0.068). (2) A t-test was performed for each concentration-time point vs. mean C(ss), and the first point with no significance was defined, T(ss). This gave 208 (p = 0.09) and 178 min (p = 0.24) with and without bolus respectively. Mathematical modelling suggests that an ideal mean bolus should be 0.89 U, and that this bolus dose may result in a shorter T(ss).

CONCLUSION

A bolus of 1.4 U resulted in an overshoot of serum IAsp before C(ss) and a longer period before C(ss) is achieved. Mathematical modelling suggests that a mean bolus of 0.89 U would result in a faster achievement of C(ss) compared to no bolus.

Overnight CSII as supplement to oral antidiabetic drugs in type 2 diabetes

AIM

To evaluate the potential advantages of a constant overnight subcutaneous delivery of insulin in type 2 diabetic patients who fail to achieve glycaemic control on oral antidiabetics.

METHODS

Ten type 2 diabetic patients treated with oral antidiabetic drugs without gaining sufficient glycaemic control were included in this three-period study. All patients received continuous subcutaneous insulin infusion (CSII) with a short-acting insulin analogue, 2 IU/h, for 8 h during three consecutive nights (period A). Based upon the results from period A, two additional dose regimens of three nights (period B and C) were studied in random order. Serum insulin aspart, human insulin and plasma glucose (PG) profiles were recorded.

RESULTS

In period A, fasting plasma glucose (FPG) was reduced from a mean +/- s.d. (mmol/l) value of 11.6 +/- 2.9 to 5.5 +/- 1.6 (p < 0.0001) during the first night. No additional lowering of FPG was seen the two succeeding nights. FPG narrowed as the range before the infusion was 7.3-15.2 mmol/l compared with 3.6-6.1 mmol/l on the last morning after infusion. The variability in PG profile during the first and the last night of CSII was small and not significantly different. The rising insulin aspart was mirrored by a decrease in human insulin. In period B and C, similar tendencies as for period A were seen. In period A, two patients each experienced one mild hypoglycaemic episode.

CONCLUSIONS

CSII with an insulin analogue overnight effectively reduced FPG without occurrence of major hypoglycaemia in type 2 diabetic patients who fail to achieve glycaemic control on oral antidiabetic treatment.

A subcutaneous insulin pharmacokinetic model for computer simulation in a diabetes decision support role: model structure and parameter identification

OBJECTIVE

The goal of this study was to develop a unified physiological subcutaneous (SC) insulin absorption model for computer simulation in a clinical diabetes decision support role. The model must model the plasma insulin appearance of a wide range of current insulins, especially monomer insulin and insulin glargine, utilizing common chemical states and transport rates, where appropriate.

METHODS

A compartmental model was developed with 13 patient-specific model parameters covering six diverse insulin types [rapid-acting, regular, neutral protamine Hagedorn (NPH), lente, ultralente, and glargine insulin]. Model parameters were identified using 37 sets of mean plasma insulin time-course data from an extensive literature review via nonlinear optimization methods.

RESULTS

All fitted parameters have a coefficient of variation <100% (median 51.3%, 95th percentile 3.6-60.6%) and can be considered a posteriori identifiable.

CONCLUSION

A model is presented to describe SC injected insulin appearance in plasma in a diabetes decision support role. Clinically current insulin types (monomeric insulin, regular insulin, NPH, insulin, and glargine) and older insulin types (lente and ultralente) are included in a unified framework that accounts for nonlinear concentration and dose dependency. Future work requires clinical validation using published pharmacokinetic studies.

Within-patient variation of the pharmacokinetics of subcutaneously injected biphasic insulin aspart as assessed by compartmental modelling

AIMS/HYPOTHESIS

Pharmacokinetics of s.c. administered insulin preparations have been widely studied, mostly using descriptive measures such as AUC, time to peak, or the peak plasma concentration. Several compartmental modelling studies of single-bolus s.c. insulin pharmacokinetics have also appeared, with contrasting results regarding the feasibility of insulin pharmacokinetics modelling and the appropriate level of detail for such models. In this paper, we used compartmental models to study the pharmacokinetics of biphasic insulin aspart administered by multiple s.c. injections. The main objective was to assess the magnitude of the inter-and intra-subject variation in the kinetics.

MATERIALS AND METHODS

Analyses were performed on 24-h serum insulin concentrations measured in 20 type 1 diabetes subjects given three daily s.c. injections of biphasic insulin aspart.

RESULTS

Preliminary analysis of the AUC:dose ratio showed that the apparent kinetics are not constant throughout the three daily injections of the compound. A simple and robust compartmental model was shown to be appropriate for interpreting the observations, provided that one of its parameters (the first-order rate constant for transfer from the s.c. depot to plasma) is allowed to vary between injections.

CONCLUSIONS/INTERPRETATION

Population estimates of the chosen model show that intra-subject variations between injections is of the same order of magnitude as inter-subject variation, partially explaining the difficulties encountered when individually tailoring intensified insulin therapy. We conclude that the explicit consideration of a rather simple kinetic model will allow better experimental designs in the future study of s.c. insulin preparations.

Insulin Therapy: Current Alternatives

In normal humans, blood glucose and insulin are maintained within a narrow range despite wide variations in physical activity and dietary intake. At present, reproducing this pattern is an impossible task in type 1 diabetes and extremely difficult in type 2 DM. New approaches using novel insulin analogs and routes of administration, attempting to replicate physiological insulin secretion in diabetic patients, are improving the profiles of glucose levels and, thus, the quality of life. Ultra-short-acting insulin analogues and ultra-long-acting analogues are being used for prandial and basal effects with better results, lower prevalence of hypoglycemia, and, hopefully, fewer chronic complications. Non-invasive routes of administration are being developed. The most promising appears to be inhaled insulin according to studies demonstrating excellent control, apparently without significant side effects, although in relatively short-term trials. Longer-term studies to assure the safety are still necessary before recommending its extended use. This is an extensive, up-to-date review of recent advances in insulin therapy.

Reproducibility and variability in the action of injected insulin

Insulin-treated patients are generally taught to adapt their doses of insulin according to the glycemic level obtained during self-tests. They usually adhere to medical recommendations, but are often confused by the results, which may not correspond to expectations. Patients have to contend with variability and a certain degree of unpredictability in the results. Our knowledge of the factors involved in this variability is often imprecise. We review here the factors depending on the preparation of insulin itself, not only with regard to its crystallization but also the speed at which the hexamers dissociate into dimers. The development of fast and slow-acting analogues is discussed along with their value in improving glycemic predictability. In addition to these factors, we mention those stemming from the injection technique itself, which are directly related to the instructions given to the patients. For crystallized insulin preparations, shaking the bottle is an important element that the development of slow-acting analogues should eliminate, but the time lapse before withdrawing the needle, the anatomical site of the insulin injection, and the depth of the injection are also factors for variability. Greater predictability in the action of insulin will be obtained from a combination of progress in manufacturing procedures and better patient education.

Pharmacokinetic profiles of biphasic insulin aspart 30/70 and 70/30 in patients with Type 1 diabetes: a randomized double-blinded crossover study

AIMS

To compare pharmacokinetic characteristics of two biphasic insulin aspart (BIAsp) formulations: BIAsp30 and BIAsp70 (30% and 70%, respectively, of fast-acting insulin aspart) during 15 days of multiple dosing (thrice daily).

METHODS

A total of 22 patients with Type 1 diabetes (nine women, 13 men) aged 41.4 +/- 9.9 years (mean +/- sd) with a diabetes duration of 18.9 (2.3-40.3) years (median and range) completed the randomized, double-blinded, two-period crossover study. On day 1 and day 15 of each treatment period, 24-h serum insulin and glucose profiles were evaluated. Total area under the insulin aspart concentration-time curve (AUC(0-24 h)), AUC after dinner administration stratified into early (AUCdinner(0-6 h)) and intermediate-phase (AUCdinner(6-14 h)), maximum insulin concentration (Cmax), time to maximum insulin concentration (Tmax) after each meal were recorded.

RESULTS

On day 15 BIAsp70 was associated with a shorter Tmax, and more than 40% elevated Cmax. Comparing with BIAsp30, AUC(0-24 h) and AUCdinner(0-6 h) were increased by 25% and 28%, respectively, but AUCdinner (6-14 h) was markedly lower for BIAsp70 [BIAsp30/BIAsp70: 1.9; 95% CI (1.42, 2.55)]. Similar findings were also observed on day 1. The fasting or pre-meal serum insulin levels on day 15 tended to be higher with BIAsp30, but the differences were not statistically significant. CONCLUSIONS The pharmacokinetic properties of BIAsp30 and 70 remain constant during 2 weeks of daily administration in patients with Type 1 diabetes. In comparison with BIAsp30, the administration of BIAsp70 results in a shorter time to and larger maximum insulin aspart concentration. Furthermore, total and early post-dinner insulin AUC were greater, whereas late-phase insulin exposure was lower with BIAsp70.

Insulin Aspart

Insulin aspart (NovoRapid, NovoLog) is a short-acting insulin analogue, which has a faster onset and shorter duration of action than regular human insulin. Insulin aspart administered immediately before meals provided significantly greater improvements in glycosylated haemoglobin and better postprandial glycaemic control than regular human insulin administered 30 minutes before meals, when used in a basal-bolus regimen with neutral protamine Hagedorn (NPH) insulin, in randomised, nonblind studies in patients with type 1 diabetes mellitus. In patients with type 2 diabetes, insulin aspart provided similar glycaemic control to regular human insulin, administered in a basal-bolus regimen with NPH insulin. Small studies suggest that the use of insulin aspart in combination with oral hypoglycaemic agents may be beneficial. Insulin aspart, administered by continuous subcutaneous insulin infusion (CSII) provided better glycaemic control than insulin aspart multiple daily injection regimens in patients with type 1 (but not type 2) diabetes, and had similar efficacy to CSII with insulin lispro or regular human insulin in type 1 diabetes. Limited studies show insulin aspart to be effective in children, adolescents and young adults with type 1 diabetes. Insulin aspart had a tolerability profile similar to that of regular human insulin in clinical trials. The incidence of major or nocturnal hypoglycaemic events reported in patients receiving insulin aspart was lower than that of regular human insulin in several studies. In conclusion, insulin aspart, administered immediately before meals in a basal-bolus regimen with NPH insulin, provided better long-term glycaemic control than regular human insulin administered 30 minutes before meals in patients with type 1 diabetes, and was as effective as regular human insulin in patients with type 2 diabetes. A significantly lower risk of hypoglycaemia was seen in several trials. Insulin aspart CSII provided better glycaemic control than insulin aspart multiple daily subcutaneous injection (MDI) in patients with type 1 (but not type 2) diabetes and had similar efficacy to CSII with insulin lispro or regular human insulin in type 1 diabetes. Insulin aspart is an effective and well tolerated alternative to regular human insulin and insulin lispro for the maintenance of glycaemic control in patients with type 1 or 2 diabetes.

Comparison between the effects of the rapid recombinant insulin analog aspart and those of human regular insulin on platelet cyclic nucleotides and aggregation

INTRODUCTION

Insulin aspart is a rapid insulin analog used in clinical practice: aim of the present study is to evaluate in human platelets its influence on: (i). concentrations of guanosine 3':5'-cyclic monophosphate (cGMP) and adenosine 3':5'-cyclic monophosphate (cAMP), mediators of platelet anti-aggregation; (ii). platelet aggregation to adenosine-5 diphosphate.

MATERIALS AND METHODS

In human platelets, incubated with human regular insulin or with insulin aspart, we measured: (1). guanosine 3':5-cyclic monophosphate and adenosine 3':5'-cyclic monophosphate concentrations by radioimmunoassays, with and without nitric oxide synthase (NOS) inhibition by N(G)-monomethyl-L-arginine, and phosphatidylinositol-3-kinase inhibition by wortmannin; (ii). aggregation to adenosine-5 diphosphate by Born's method.

RESULTS

(i). Human regular insulin and insulin aspart increased both cyclic nucleotides; (ii). these effects were dependent on nitric oxide, being inhibited by N(G)-monomethyl-L-arginine, and mediated by the phosphatidylinositol-3-kinase pathway of insulin signalling, being inhibited by wortmannin; (iii). the effects exerted by insulin aspart on both cyclic nucleotides (ANOVA, p=0.0001) were more prolonged than those exerted by regular insulin; (iv) like human regular insulin, insulin aspart significantly decreased platelet response to ADP (ANOVA, p=0.0001): after 60 min of incubation, the anti-aggregating effect exerted by insulin aspart was significantly greater than that exerted by human regular insulin (p=0.027).

CONCLUSIONS

The effects of insulin aspart on platelet cyclic nucleotides and aggregation show kinetic differences compared to those of human regular insulin, resulting in more prolonged effects.

New insulins in the treatment of diabetes mellitus

Landmark studies have confirmed the importance of intensified insulin treatment for minimizing long-term diabetic complications. Human insulin is still first-line treatment. However, even the most intensive of human insulin-based regimens can only poorly reproduce physiologically desirable insulin release, which includes rapid outbursts of insulin at mealtimes coupled with relatively low and stable basal levels between meals. Encouragingly, there are now four available or soon-to-be-available insulin analogues that offer the potential for more physiological insulin profiles. Insulin lispro and insulin aspart are rapid-acting insulin analogues intended for immediate pre-meal administration in type 1 or type 2 diabetes. Compared with injected human insulin, they improve post-prandial glucose control and reduce late post-meal and night-time hypoglycaemic episodes. Two basal insulin analogues, insulin glargine and insulin detemir, have also shown beneficial profiles with regard to night-time hypoglycaemia.Some, but not all, studies with the two rapid-acting insulins have shown improvement in overall glucose control, as assessed by HbA(1c), in comparison to human insulin. These results are encouraging and provide hope that entirely analogue-based regimens may improve overall glycaemic control and ease of use of insulin.

Use of a novel double-antibody technique to describe the pharmacokinetics of rapid-acting insulin analogs

OBJECTIVE

To measure the contribution of bedtime intermediate-acting human insulin on the morning plasma insulin profiles after injection of the rapid-acting insulin analogs lispro and aspart in patients with type 1 diabetes.

RESEARCH DESIGN AND METHODS

A total of 14 patients with type 1 diabetes, aged 35 +/- 13 years (mean +/- SD), participated in this single-blind, randomized crossover study. After taking their usual injection of human intermediate-acting insulin the night before, they were given insulin aspart or insulin lispro (10 units) before a standardized breakfast. The contribution of continuing absorption of the human insulin was measured using a monoclonal antibody not cross-reacting with insulin aspart or lispro, whereas the contribution of the analogs was estimated by subtraction after measurement of all plasma free insulin using an antibody cross-reacting equally with human insulin and both analogs.

RESULTS

The correlation coefficient of the fasting free insulin concentrations measured with both insulin methods was 0.95. Fasting free insulin was 95 +/- 25 pmol/l before administration of insulin aspart, when determined with enzyme-linked immunosorbent assay detecting only human insulin, and 71 +/- 20 pmol/l before administration of insulin lispro (NS). Both insulin analogs gave marked peaks of free insulin concentrations, lispro at 40 +/- 3 min and aspart at 55 +/- 6 min after injection (P = 0.01). The later part of the profiles, from 4.5 to 5.5 h after injection, were similar and showed almost no contribution of the insulin analogs.

CONCLUSIONS

The combination of insulin assays that detect human insulin only or both human insulin and analogs provides a new tool for studying insulin pharmacokinetics. Using this technique, we showed that 4.5 h after administration of the rapid-acting insulin analogs lispro and aspart, the free insulin levels are almost only attributable to the intermediate-acting insulin given at bedtime.

Clinical pharmacokinetics and pharmacodynamics of insulin aspart

Insulin aspart is a novel rapid-acting insulin analogue with improved subcutaneous absorption properties when compared with soluble human insulin. Pharmacokinetic studies show an absorption profile with a time to reach peak concentration (t(max)) about half that of human insulin, a peak plasma drug concentration (Cmax) approximately twice as high and shorter residence time. The potency and bioavailability of insulin aspart are similar to those of human insulin. The pharmacokinetics of insulin aspart have been studied in healthy Caucasian and Asian-Japanese volunteers, in patients with type 1 and 2 diabetes mellitus, and in children with diabetes, with both pre- and postprandial administration and during continuous subcutaneous insulin infusion (CSII). The pharmacokinetic profile was similar to that of another rapid-acting insulin analogue, insulin lispro, on the basis of published information for that agent. Pharmacodynamic studies show a smaller excursion of postprandial glucose with insulin aspart injected subcutaneously just before the meal compared with soluble human insulin injected 30 minutes before the meal in patients with type 1 diabetes mellitus, and an equivalent control in patients with type 2 diabetes displaying residual insulin production. In a treatment study, glucose excursions evaluated from 24-hour glucose profiles showed less variability with insulin aspart compared with human insulin. Adverse events, including hypoglycaemia-induced ventricular repolarisation and hypoglycaemic threshold and awareness, did not differ between insulin aspart and human insulin. The available data suggest that subcutaneous injections of insulin aspart just before meals better mimic the endogenous insulin profile in blood compared with human insulin, resulting in improved glucose control in a meal-related insulin regimen. This review summarises the clinical pharmacokinetics and pharmacodynamics of insulin aspart in relation to human insulin and insulin lispro.

New aspects of insulin therapy in type 1 and type 2 diabetes

Tight control of the blood glucose level decreases the frequency of complications of both type 1 and type 2 diabetes mellitus. Until recently, the available short, intermediate, and long-acting forms of insulin could not readily be used to achieve tight glycemic control without introducing an unacceptably high risk of hypoglycemia or demanding an impracticably rigid lifestyle. With the introduction of faster-acting insulin analogues, lispro and aspart, and a peakless long-acting insulin analogue, glargine, the goal of safe and effective tight glycemic control may now be within reach for many patients. The use of these new insulins allows the clinician and patient an expanded range of options for achieving good control of fasting and postprandial blood glucose levels.