Needle-free jet injection of rapid-acting insulin improves early postprandial glucose control in patients with diabetes

Effectiveness, safety, and preference of transdermal insulin compared to subcutaneous insulin in the treatment of diabetes patients: a systematic review of clinical trials

BACKGROUND

Several studies were performed on transdermal (TD) insulin delivery in vitro and in vivo, and recently, the study groups included a clinical trial in humans. Therefore, this systematic review was conducted to get summary information about the effectiveness, safety, and preferability of TD insulin in comparison with subcutaneous insulin delivery.

METHODS

We conducted a thorough search to find studies in the databases Cochrane Library, MEDLINE via PubMed, Web of Science Core Collection, EMBASE, Scopus, Hinari, Medlib, and Magiran until January 2024. We included 18 randomized clinical trials.

RESULTS

Although there are various types of TD delivery methods, the TD insulin delivery methods that have undergone clinical trials are the TD patch, micro needle TD insulin delivery, and TD insulin jet injector. Eighteen studies were conducted on TD insulin delivery, which showed either superior or comparable effectiveness, safety, and preferability of TD insulin in comparison with SC insulin. About eleven out of eighteen studies (61.1%) showed more effective blood glucose control than SC delivery, and the remaining seven studies showed comparable effectiveness with SC delivery. Eleven studies (61.1%) showed equal tolerability of TD insulin versus SC insulin, and seven studies (38.9%) showed more tolerability of TD insulin over SC insulin. In most studies, eleven out of eighteen (61.1%) showed a higher preference for TD insulin delivery over traditional SC delivery; sixth out of eighteen (33.3%) showed equal preferability for TD insulin versus SC insulin; and only one study (5.6%) showed that TD insulin delivery was less preferable than SC insulin.

CONCLUSION

The review revealed that clinical trials have demonstrated the effectiveness of TD insulin delivery methods such as TD patches, MN-based insulin delivery, and insulin jet injectors compared to traditional SC routes of administration. The studies showed the superior or comparable effectiveness of TD insulin in controlling blood glucose levels. Additionally, TD insulin delivery was found to be equally or more tolerable than SC insulin delivery in all studies. Overall, the majority of studies favored TD insulin delivery over traditional SC delivery methods, highlighting its potential as a preferred option for insulin administration.

Surgical Site Infiltration with Comfort-in Device and Traditional Syringe in Dogs Undergoing Regional Mastectomy: Evaluation of Intra- and Postoperative Pain and Oxidative Stress

The surgical site infiltration of a local anesthetic is defined as the direct injection of a drug. This study aimed to compare the effects of surgical site infiltration with 4 mg kg-1 lidocaine using a Comfort-in device and traditional syringe on oxidative status and intra- and postoperative pain in dogs undergoing regional mastectomy. Sixty adult female dogs divided into C (Comfort-in device), S (traditional syringe), and CTR (control) groups received 2 µg kg-1 dexmedetomidine and 4 mg kg-1 tramadol IM, 5 mg kg-1 tiletamine/zolazepam IV, and isoflurane. The physiological and anesthesiological parameters were measured. The assessment of intra- and postoperative responses to the surgical stimulus was performed using a cumulative pain scale (CPS score of 0-4) and the Colorado Pain Scale (CSU-CAPS score of 0-4). The hematological and biochemical parameters and inflammatory oxidative status were measured. The CPS scores showed no significant differences between the C and S groups (p = 0.236), while the comparison between the CTR, C, and S groups, respectively, showed a significant difference (p < 0.001). The postoperative analgesia scores were significantly lower in the C group compared to those of the S and CTR groups (p < 0.001). In the C group, no subject received rescue analgesia during the intra- and postoperative periods. The level of oxidative inflammatory stress was lower in group C than those in S and CTR groups, and no side effects were observed in all the groups.

Effectiveness of Insulin Pump Therapy Versus Multiple Daily Injections for Glycemic Control and Rate of Diabetic Ketoacidosis Among Children With Type 1 Diabetes Mellitus

Background Advances in pump technology and the availability of insulin analogs, as well as the results of the Diabetes Control and Complications Trial (DCCT), which established the benefit of improved glycemic control, have all contributed to the increased use of insulin pump therapy in recent years, particularly in children. Purpose This research aims to compare the impact of insulin delivery method, i.e., continuous subcutaneous insulin infusion (CSII) or multiple daily injections (MDI) on glycemic control and the rate of diabetic ketoacidosis (DKA) among children with type 1 diabetes mellitus in Al Ahsa, Saudi Arabia. Methods  A retrospective cohort study was carried out in a diabetic center in Al Ahsa, Saudi Arabia, over 24 months (2020-2022) among children with type I diabetes mellitus (age group 1-14 years). Results  In total, 351 patients with diabetes were induced, with 316 (90%) on MDI and 35 (10%) on CSII. After six months of diagnosis, precisely 38 (12%) of patients with diabetes on the MDI regimen experienced DKA, compared to 4 (11.4%) of those on the CSII regimen, with no statistically significant difference (P=0.918). At six months and nine months of follow-up, the average hemoglobin A1c (HbA1c) was considerably higher in diabetic patients on MDI (8.9 ± 1.7% vs. 8.2 ± 1.5% and 9.1 ± 1.6% vs. 8.0 ± 1.3%, respectively, with a significant p-value ≤0.05). Conclusion In this study, we found that patients on the MDI regimen had considerably higher HbA1c levels than patients on the CSII regimen, but there was no statistically significant difference in DKA rates between them. This is a short-term follow-up study, and we recommend that patients be followed for a longer period of time for further accurate outcomes.

Injectable systems for long-lasting insulin therapy

Insulin therapy is the mainstay to treat diabetes characterizedd by hyperglycemia. However, its short half-life of only 4-6 min limits its effectiveness in treating chronic diabetes. Advances in recombinant DNA technology and protein engineering have led to several insulin analogue products that have up to 42 h of glycemic control. However, these insulin analogues still require once- or twice-daily injections for optimal glycemic control and have poor patient compliance and adherence issues. To achieve insulin release for more than one day, different injectable delivery systems including microspheres, in situ forming depots, nanoparticles and composite systems have been developed. Several of these delivery systems have advanced to clinical trials for once-weekly insulin injection. This review comprehensively summarizes the developments of injectable insulin analogs and delivery systems covering the whole field of injectable long-lasting insulin technologies from prototype design, preclinical studies, clinical trials to marketed products for the treatment of diabetes.

A Scientometric Analysis and Visualization of Scientific Research and Technology Innovation in Needle-free Insulin Injection From 1974 to 2022

PURPOSE

Needle-free jet injection has to some extent improved the quality of life of patients with diabetes, but it has not been widely used. Therefore, we analyzed articles, clinical trials, and patents of needle-free insulin injection to (1) perform a systematic and comprehensive analysis of scientific research and technology innovation in needle-free insulin injection during the past 49 years (1974 to 2022) and (2) identify the status of scientific research and technology innovation, their limitations, and future trends.

METHODS

With a new perspective, we use scientometric tools, including co-word and word frequency analyses, text mining, and cluster network analysis, to provide a scientometric analysis and visualization of articles, clinical trials, and patents related to needle-free insulin injection delivery applications.

FINDINGS

Patent innovation in this field was more active than clinical research, and clinical research prevailed over basic research. Basic research and clinical trials in this field mainly involved therapy, penetration, tolerability, absorption, and pharmacokinetic properties. Drive mechanisms and needle-free injection devices were the core patent technologies in this field.

IMPLICATIONS

Although needle-free insulin injection has been under development for decades, its full potential has not yet been reached; needle-free injection technology is still in the growth stage. The field of needleless insulin injection is dominated by patent technology innovation.

A clinical observation study on the effect of needle-free insulin syringe on blood glucose control and well-being index in patients with early-onset type 2 diabetes mellitus

OBJECTIVE

To explore the effect of using needle-free insulin syringe on blood sugar control and well-being index in patients with early-onset type 2 diabetes mellitus.

METHODS

A total of 42 patients with early-onset type 2 diabetes mellitus treated with insulin aspart 30 injection in a stable condition in the Endocrinology Department of a tertiary hospital from January 2020 to July 2021 were randomly divided into two groups, one group received insulin pen injections followed by needle-free injections, and the other group received needle-free injections followed by insulin pen injections. Transient scanning glucose monitoring was performed during the last two weeks of each injection modality phase. Comparison of the two injection methods in terms of test indicators and differences in injection site pain scores, the number of red spots on the skin at the injection site and the number of bleeding spots on the skin at the injection site.

RESULTS

The FBG of the needle-free injection group was lower than that of the Novo Pen group (p<0.05); the 2-hour postprandial blood glucose of the needle-free injection group was lower than that of the Novo Pen group, but there was no statistical significant difference. The amount of Insulin in the needle-free injector group was lower than that in the Novo pen group, but there was no statistical significant difference between the two groups. The WHO-5 score of the needle-free injector group was higher than that of the Novo Pen group(p<0.05); the pain score at the injection site was lower than that of the Novo Pen group (p<0.05). The number of skin red spots using the needle-free syringe was more than that of the Novo pen group(p<0.05); the number of skin bleeding at the site of injection was similar between the two injection methods.

CONCLUSION

Compared to traditional insulin pens, subcutaneous injection of premixed insulin using a needle-free syringe is effective in controlling fasting blood glucose in patients with early onset type 2 diabetes and is less painful at the injection site. In addition, blood glucose monitoring should be strengthened and insulin dosage should be adjusted in a timely manner.

Needle-free injection of basal insulin improves fasting glucose variability as assessed by continuous glucose monitoring in T2DM: a prospective randomized multicenter open-label crossover study

BACKGROUND

Fasting glucose variability (FGV) extensively promotes the onset and development of diabetic complications. This study aimed to evaluate the FGV in type 2 diabetes mellitus (T2DM) patients administered basal insulin using a needle-free insulin injector (NFII).

RESEARCH DESIGN AND METHODS

This was a prospective randomized multicenter open-label crossover study. We randomly assigned 48 T2DM patients to receive basal insulin by NFII or conventional insulin pen (CIP) for 7-14 days and were then crossed over after washout. We conducted continuous glucose monitoring to investigate the FGV, our primary outcome was a composite parameter of the FGV with a fasting blood glucose target between 4.4 and 6.1 mmol/L.

RESULTS

The coefficient of variation for sensor glucose at 6 a.m. with CIP was 11.67 (8.70,14.81)% vs. 9.48 (6.48,12.24)% with NFII (p = 0.003), and the coefficient of variation for mean sensor glucose at 5-6 a.m. with CIP was 12.70 (9.17,16.56)% vs. 9.23 (7.01,11.98)% with NFII (p < 0.001). The overall basal insulin dosage with CIP injection was 18.00 (16.00, 20.00) IU vs. 16.00 (12.00, 19.00) IU during NFII (p < 0.003).

CONCLUSION

Compared with CIP, the use of the NFII to inject basal insulin improved FGV in T2DM.

CLINICAL TRIAL REGISTRATION

https://www.chictr.org.cn Identifier is ChiCTR2000034674.

The Absorption of Needle-Free Insulin Aspart Through Jet Injector in Different Body Parts of Healthy Individuals

The absorption of needle-free fast-acting insulin injected into different body parts of healthy male subjects was studied in an attempt to provide clinical guidance for diabetic patients who take needle-free insulin injections in terms of providing reference in the clinical guidance regarding the correct use of needle-free insulin injections among diabetic patients. This randomized, open-label, cross-over trial was conducted on eight healthy adult male volunteers, in which the skin thickness at three injection sites (abdomen, upper arm, and thigh), the time to peak, peak rate, and area under the glucose infusion rate (GIR) curve of plasma insulin were measured through the hyperinsulin-normal glucose clamp test after the injection of insulin aspart with a needle-free syringe at three different sites to analyze the correlation between insulin absorption index at different injection sites and skin thickness. The values of the skin thickness of the abdomen, upper arm, and thigh measured by ultrasonic wave were 2.45 ± 0.34 mm, 2.18 ± 0.50 mm, and 1.93 ± 0.55 mm, respectively. There was a significant difference in the skin thickness of the abdomen and thigh (P = 0.014). The hyperinsulin-normal glucose clamp model was successfully established for each subject. Approximately 0-2 h after injection of insulin aspart with needle-free syringes, the area under the GIR-time curve of the abdomen, upper arm, and thigh was 29,400.75 ± 2,645.00 ml, 30,230.50 ± 4,937.87 ml, and 30,179.63 ± 6,188.57 ml, respectively. There was no significant difference in the area under the GIR curve between any two injection sites (P >0.05). The time to peak of GIR at different injection sites was 38.68 ± 13.57 min in the abdomen, 40.86 ± 12.70 min in the upper arm, and 37.03 ± 13.29 min in the thigh, respectively, in which no significant difference was found between each of them (P >0.05). The GIR curve after injection at the three different sites was consistent with each other. There was no significant difference in insulin absorption after the injection of insulin aspartate into the abdomen, upper arm, and thigh with a needleless syringe in healthy male adult volunteers, and there was no correlation between skin thickness at the injection site and insulin absorption. Injection sites did not affect the absorption of insulin in needle-free injections.

Needle-free jet injection of insulin glargine improves glycemic control in patients with type 2 diabetes mellitus: a study based on the flash glucose monitoring system

Background: To investigate the effects of insulin glargine injection given with a QS-P jet injector on the glucose profile using a professional mode flash glucose monitoring (FGM) system in patients with type 2 diabetes mellitus (T2DM).Research design and methods: In this randomized, controlled, cross-sectional study, 66 patients with T2DM who received insulin glargine (12-18 IU/day) injection were enrolled. The patients were randomly divided into group A (jet injector before insulin pen) and group B (insulin pen before jet injector). Each subject injected insulin daily before breakfast. We analyzed the changes in the glucose profile using a professional mode FGM system.Results: Treatment with a jet injector led to significantly lower 24-h mean glucose, maximum blood glucose, area under the curve (AUC) > 10.0 mmol/L, time above range and increased AUC < 3.9 mmol/L and time below range than those when using an insulin pen. There was no difference in glycemic variability between the two groups. We observed that patients using a jet injector had significantly lower mean glucose between 12:00 to 22:00.Conclusions: Needle-free jet injection of insulin glargine was more effective than use of an insulin pen for good glycemic control in patients with T2DM.Clinical trial registration: www.clinicaltrials.gov identifier is NCT04093284.

Developing Insulin Delivery Devices with Glucose Responsiveness

Individuals with type 1 and advanced type 2 diabetes require daily insulin therapy to maintain blood glucose levels in normoglycemic ranges to prevent associated morbidity and mortality. Optimal insulin delivery should offer both precise dosing in response to real-time blood glucose levels as well as a feasible and low-burden administration route to promote long-term adherence. A series of glucose-responsive insulin delivery mechanisms and devices have been reported to increase patient compliance while mitigating the risk of hypoglycemia. This review discusses currently available insulin delivery devices, overviews recent developments towards the generation of glucose-responsive delivery systems, and provides commentary on the opportunities and barriers ahead regarding the integration and translation of current glucose-responsive insulin delivery designs.

Insulin delivery with a needle-free insulin injector versus a conventional insulin pen in Chinese patients with type 2 diabetes mellitus: A 16-week, multicenter, randomized clinical trial (the FREE study)

BACKGROUND

Insulin therapy is poorly accepted by patients with type 2 diabetes mellitus (T2DM). A needle-free insulin injector has been developed for patients who fear injections or are reluctant to initiate insulin therapy when it is clearly indicated. The objective of this trial was to evaluate the glucose-lowering effect, tolerability, patient satisfaction and compliance with insulin treatment via a needle-free insulin injector (NFII) compared with insulin treatment via a conventional insulin pen (CIP) in patients with T2DM.

METHODS

A total of 427 patients with T2DM were enrolled in a prospective, multicenter, randomized, open-label study, and were randomly assigned 1:1 to receive 16 weeks' treatment with basal insulin or premixed insulin administered either by a NFII or CIP.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT03243903).

FINDINGS

In the 412 patients who completed the study, the adjusted mean reduction of HbA1c from baseline at week 16 in the NFII group was 0.55% (95% CI -0.71, -0.39), which was non-inferior and statistically superior to the HbA1c reduction in the CIP group (0.26%, 95% CI -0.42, -0.11). Patients in the NFII group showed significantly higher treatment satisfaction scores than those in the CIP group (mean scores, 8.17 ± 1.78 vs. 7.21 ± 2.22, respectively; p<0.0001). The occurrence of hypoglycemia was similar in the two groups, and the NFII group showed reduced incidences of skin scratches, indurations and lower VAS pain scores.

INTERPRETATION

Insulin therapy through needle-free injector showed a non-inferior glycemic-lowering effect and a significantly enhanced level of patient satisfaction with insulin treatment compared with conventional insulin therapy through needle injections. In addition, the needle-free injector also had a better safety profile.

FUNDING

This study were funded by Beijing QS Medical Technology Co., Ltd, as well as The Major Chronic Non-communicable Disease Prevention and Control Research.

Comparison of glucose variability in patients with type 2 diabetes administrated glargine with needle-free jet injector and conventional insulin pen

Background: The effects of insulin delivered by needle-free jet injector on glycemic variations (GV) in patients with type 2 diabetes (T2D) which remains largely unknown.Research design and methods: We aimed to compare the glucose variability in Chinese T2D patients administrated glargine 100 U/mL (Gla-100) with a needle-free jet injector and conventional insulin pen. This was a self-comparative, observational study of 26 patients who were subjected to a flash glucose monitoring system (FGM) for 14 consecutive days. During the study period, all subjects received Gla-100 daily before breakfast using a conventional insulin pen, with the exception of day 3 and day 7, when insulin was delivered by needle-free jet injection. We analyzed FGM data of day 3, day 5, day 7, and day 9 at the endpoint.Results: There were no differences in the glycemic variability between the jet injector group and the conventional pen group. However, patients with needle-free jet injection had a lower 24 hr mean glucose (MG) and lower incremental area under the curve (AUC) of 1 hr, 12 hr, and 24 hr, compared to the conventional pen group (p = 0.001).Conclusions: Gla-100 delivered by needle-free jet injection potentially lowered MG in patients with T2D in the Chinese population.

Efficacy and safety of a needle-free injector in Chinese patients with type 2 diabetes mellitus treated with basal insulin: a multicentre, prospective, randomised, crossover study

Objective: To evaluate the efficacy and safety of a needle-free injector in Chinese patients with type 2 diabetes mellitus treated with basal insulin. Methods: 62 patients with type 2 diabetes were enrolled in a multicenter, randomised, prospective, open-label, crossover study. All patients received subcutaneous insulin glargine administered by a needle-free injector or a glargine pen for 7 ~ 14 days, and were then crossed over after wash out. Results: Patients in the insulin needle-free injector (NFI) and glargine pen (GP) groups achieved similar fasting blood glucose control . However, the dosage of insulin required to achieve the target FBG level in the NFI group was lower than in the GP group (16.14 ± 5.13 U/day vs 19.25 ± 6.20 U/day, respectively; p = 0.0046). This difference was more significant in patients who received higher insulin dosages compared with those receiving lower dosages. Use of the needle-free injector was also associated with significantly less pain (p < 0.001) and less fear of injection (p < 0.001) than glargine pens. Conclusion: The use of a needle-free injector can significantly lower the dosage of insulin required to achieve good glycemic control and reduce topical adverse reactions and the fear of injections as well, which help to improve patient compliance. Clinical Trial Registration Number KY20172077-1; NCT03420040.

An Electronic Force Sensor for Medical Jet Injection

In medical jet injection, a narrow fluid drug stream is propelled at high velocity into skin without a needle. Previous studies have shown that the volume delivered is highly dependent on a number of factors. This paper details the development of an electronic force sensor for medical jet injection and shows that the normal contact force exerted on the tissue by the nozzle is an additional factor affecting volume delivered. Using this sensor, we measure the forces at the nozzle tip in the normal direction with a sensitivity of 18 μN, calibrated over a range from 1 N to 8 N with a mean absolute error of 8 mN, and a maximum overload of 300 N. We further measure forces at the nozzle tip in the lateral direction with a sensitivity of 8 μN, calibrated over a range from 0.1 N to 7 N, with a mean absolute error of 101 mN for lateral contact force magnitude and 1.60 deg for lateral contact force direction. Experimental validation confirms that the force sensor does not adversely affect the accuracy and precision of ejected volume from the jet injector. We use this setup to examine the effect of normal contact force on volume delivered into postmortem porcine tissue. Experimental results demonstrate that volume delivered with normal contact force between 4 N and 8 N is significantly more accurate and precise compared to volume delivered with normal contact force between 0 N and 3.9 N.

Advances in transdermal insulin delivery

Insulin therapy is necessary to regulate blood glucose levels for people with type 1 diabetes and commonly used in advanced type 2 diabetes. Although subcutaneous insulin administration via hypodermic injection or pump-mediated infusion is the standard route of insulin delivery, it may be associated with pain, needle phobia, and decreased adherence, as well as the risk of infection. Therefore, transdermal insulin delivery has been widely investigated as an attractive alternative to subcutaneous approaches for diabetes management in recent years. Transdermal systems designed to prevent insulin degradation and offer controlled, sustained release of insulin may be desirable for patients and lead to increased adherence and glycemic outcomes. A challenge for transdermal insulin delivery is the inefficient passive insulin absorption through the skin due to the large molecular weight of the protein drug. In this review, we focus on the different transdermal insulin delivery techniques and their respective advantages and limitations, including chemical enhancers-promoted, electrically enhanced, mechanical force-triggered, and microneedle-assisted methods.

Factors Affecting the Absorption of Subcutaneously Administered Insulin: Effect on Variability

Variability in the effect of subcutaneously administered insulin represents a major challenge in insulin therapy where precise dosing is required in order to achieve targeted glucose levels. Since this variability is largely influenced by the absorption of insulin, a deeper understanding of the factors affecting the absorption of insulin from the subcutaneous tissue is necessary in order to improve glycaemic control and the long-term prognosis in people with diabetes. These factors can be related to either the insulin preparation, the injection site/patient, or the injection technique. This review highlights the factors affecting insulin absorption with special attention on the physiological factors at the injection site. In addition, it also provides a detailed description of the insulin absorption process and the various modifications to this process that have been utilized by the different insulin preparations available.

An Innovative Needle-free Injection System: Comparison to 1 ml Standard Subcutaneous Injection

A needle-free delivery system may lead to improved satisfaction and compliance, as well as reduced anxiety among patients requiring frequent or ongoing injections. This report describes a first-in-man assessment comparing Portal Instruments' innovative needle-free injection system with subcutaneous injections using a 27G needle. Forty healthy volunteer participants each received a total of four injections of 1.0 mL sterile saline solution, two with a standard subcutaneous injection using a 27G needle, and two using the Portal injection system. Perception of pain was measured using a 100-mm visual analog scale (VAS). Injection site reactions were assessed at 2 min and at 20-30 min after each injection. Follow-up contact was made 24-48 h after the injections. Subject preference regarding injection type was also assessed. VAS pain scores at Portal injection sites met the criteria to be considered non-inferior to the pain reported at 27G needle injection sites (i.e., upper 95% confidence bound less than +5 mm). Based on a mixed effects model, at time 0, accounting for potential confounding variables, the adjusted difference in VAS scores indicated that Portal injections were 6.5 mm lower than the 27G needle injections (95% CI -10.5, -2.5). No clinically important adverse events were noted. Portal injections were preferred by 24 (60%) of the subjects (P = 0.0015). As an early step in the development of this new needle-free delivery system, the current study has shown that a 1.0-mL saline injection can be given with less pain reported than a standard subcutaneous injection using a 27G needle.

Pharmacokinetic and Pharmacodynamic Variability of Insulin When Administered by Jet Injection

BACKGROUND

Jet injection has been shown to accelerate the absorption and action of rapid-acting insulin. In this study, we compared the variability of absorption characteristics between jet injection and conventional administration of the rapid-acting insulin analogue aspart.

METHODS

A total of 30 healthy volunteers were enrolled in this randomized controlled blinded parallel study. On two test days, they received insulin aspart (0.2 units/kg body weight), either by jet injection or conventional pen, followed by a 6-hour euglycemic glucose clamp. Plasma glucose and insulin levels and glucose infusion rates were measured every 5 to 10 minutes to calculate the variability in pharmacological endpoints.

RESULTS

Jet injection advanced the times until maximal insulin concentration (T-INS_max) and glucose infusion rate (T-GIR_max) by ~40% (both P < .01). The difference between the two test days for these endpoints did not differ between jet injection and conventional administration (T-INS_max: 7.3 ± 1.9 vs 22.3 ± 6.3 min, P = .074; T-GIR_max: 24.0 ± 3.5 vs 27.3 ± 6.6 min, P = .66). The corresponding intraindividual coefficients of variation for injection by jet or conventional pen were 15.3 ± 3.3 and 22.0 ± 4.6% ( P = .25, P_variance = .044) for T-INS_max and 34.5 ± 5.1 and 21.2 ± 4.6% for T-GIR_max ( P = .064, P_variance = .62). The variance in maximal insulin concentration was significantly less after conventional administration ( P = .039). The variance in total glucose-lowering effect and total insulin exposure did not differ ( P = .93 and P = .32) Conclusion: Using a jet injector for insulin administration was associated with slightly altered variability in pharmacokinetic endpoints, but with about similar variability in pharmacodynamic endpoints compared to conventional administration. Variability in these endpoints remains considerable, regardless of the method of insulin administration.

Personalized glucose-insulin model based on signal analysis

Glucose plasma measurements for diabetes patients are generally presented as a glucose concentration-time profile with 15-60min time scale intervals. This limited resolution obscures detailed dynamic events of glucose appearance and metabolism. Measurement intervals of 15min or more could contribute to imperfections in present diabetes treatment. High resolution data from mixed meal tolerance tests (MMTT) for 24 type 1 and type 2 diabetes patients were used in our present modeling. We introduce a model based on the physiological properties of transport, storage and utilization. This logistic approach follows the principles of electrical network analysis and signal processing theory. The method mimics the physiological equivalent of the glucose homeostasis comprising the meal ingestion, absorption via the gastrointestinal tract (GIT) to the endocrine nexus between the liver, pancreatic alpha and beta cells. This model demystifies the metabolic 'black box' by enabling in silico simulations and fitting of individual responses to clinical data. Five-minute intervals MMTT data measured from diabetic subjects result in two independent model parameters that characterize the complete glucose system response at a personalized level. From the individual data measurements, we obtain a model which can be analyzed with a standard electrical network simulator for diagnostics and treatment optimization. The insulin dosing time scale can be accurately adjusted to match the individual requirements of characterized diabetic patients without the physical burden of treatment.

Comparison of jet injector and insulin pen in controlling plasma glucose and insulin concentrations in type 2 diabetic patients

This study is conducted to investigate efficacy of an insulin jet injector and an insulin pen in treatment of type 2 diabetic patients. Sixty patients with type 2 diabetes were treated with rapid-acting insulin (regular insulin) and insulin analog (insulin aspart) using the jet injector and the pen in 4 successive test cycles. Postprandial glucose and insulin concentrations in blood were measured over time. Areas under curves of glucose and the insulin were calculated, and efficacy of 2 injection methods in treatment of the diabetes was compared. Regular insulin and insulin aspart administration by the jet injector showed significant decreases in plasma glucose levels as compared to the pen injection (P < 0.05). Postprandial plasma glucose excursions at the time points of 0.5 to 3 hours were obviously lower in the jet-treated patients than the pen-treated ones (P < 0.05). Postprandial plasma insulin levels were markedly higher in the jet-treated patients than the pen-treated ones (P < 0.05). Area under the glucose curve in the pen-treated patients was significantly increased as compared to the jet-treated ones (P < 0.01). Efficacy of the insulin jet injector in treatment of type 2 diabetic patients is obviously superior to the insulin pen in regulating plasma glucose and insulin levels.

A comparison of the pharmacodynamic profiles of jet-injected regular human insulin versus conventionally administered insulin aspart in healthy volunteers

AIMS

Rapid-acting insulin analogues are generally preferred over regular human insulin because of their more immediate onset of action and shorter time-action profile. However, these analogues may not always be tolerated by or universally available for people with insulin-requiring diabetes. Jet injection has been demonstrated to facilitate faster insulin absorption. We determined whether administration of regular human insulin by jet injection achieves the same pharmacological properties as that of a rapid-acting insulin analogue.

METHODS

Twenty healthy volunteers received regular human insulin (0.2units/kg) by jet injection. Glucose 20% was infused intravenously to maintain euglycaemia over six hours. The glucose infusion rates (GIR) were determined to compare pharmacological profiles. These profiles were compared with data from two other studies in which a similar dose of insulin aspart was administered by conventional pen.

RESULTS

Regular human insulin by jet injection had a faster onset of glucose-lowering effect compared to aspart by conventional pen (T-GIR_50%, 30.8±2.9 versus 43.1±3.2min, P<0.01). There were no differences in time to maximal GIR (106.1±11.9 versus 95.8±9.2min, P=0.50), maximal GIR (8.6±0.7 versus 7.7±0.7mg/kg/min, P=0.0.33), total glucose-lowering effect (101.0±9.8 versus 87.6±7.0g, P=0.28), and time until 50% of glucose disposal (144.8±5.6 versus 151.3±5.1min, P=0.39).

CONCLUSIONS

Jet-injected regular human insulin had a pharmacological profile that was essentially not dissimilar from that of aspart insulin administered by conventional pen, and can therefore be used as an alternative for conventionally administered rapid-acting insulin analogues.

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.

Insulin administered by needle-free jet injection corrects marked hyperglycaemia faster in overweight or obese patients with diabetes

AIMS

To test whether jet injection of insulin resulted in faster correction of marked hyperglycaemia than when insulin is injected by a conventional pen in patients with diabetes.

METHODS

Adult, overweight or obese (BMI ≥25 and ≤40 kg/m(2)) patients with type 1 diabetes (n = 10) or insulin-treated type 2 diabetes (n = 10) were enrolled in a randomized, controlled, crossover study. On two separate occasions, patients were instructed to reduce insulin dose(s) to achieve marked hyperglycaemia (18-23 mmol/l). Subsequently, insulin aspart was administered either by jet injection or by conventional pen, in a dose based on estimated individual insulin sensitivity. Pharmacodynamic and pharmacokinetic profiles were derived from plasma glucose and insulin levels, measured for 6 h after injection.

RESULTS

After conventional injection, plasma glucose concentration dropped by ≥10 mmol/l after 192.5 ± 13.6 min. The jet injector advanced this time to 147.9 ± 14.4 min [difference 44.6 (95% confidence interval 4.3, 84.8); P = 0.03], except in 3 patients who failed to reach this endpoint. The time advantage exceeded 1.5 h in patients with a BMI above the median. Jet injection also reduced the hyperglycaemic burden during the first 2 h (2042 ± 37.2 vs 2168 ± 26.1 mmol/min; P = 0.01) and the time to peak insulin levels (40.5 ± 3.2 vs 76.8 ± 7.7 min; P < 0.001), but did not increase the risk for hypoglycaemia.

CONCLUSIONS

Administration of rapid-acting insulin by jet injection results in faster correction of marked hyperglycaemia in overweight or obese patients with insulin-requiring diabetes.

Spatial distribution of soluble insulin in pig subcutaneous tissue: Effect of needle length, injection speed and injected volume

The spatial distribution of a soluble insulin formulation was visualized and quantified in 3-dimensions using X-ray computed tomography. The drug distribution was visualized for ex vivo injections in pig subcutaneous tissue. Pig subcutaneous tissue has very distinct layers, which could be separated in the tomographic reconstructions and the amount of drug in each tissue class was quantified. With a scan time of about 45min per sample, and a robust segmentation it was possible to analyze differences in the spatial drug distribution between several similar injections. It was studied how the drug distribution was effected by needle length, injection speed and injected volume. For an injected volume of 0.1ml and injection depth of 8mm about 50% of the injections were partly intramuscular. Using a 5mm needle resulted in purely subcutaneous injections with minor differences in the spatial drug distribution between injections. Increasing the injected volume from 0.1ml to 1ml did not increase the intramuscular volume fraction, but gave a significantly higher volume fraction placed in the fascia separating the deep and superficial subcutaneous fat layers. Varying the injection speed from 25l/s up to 300l/s gave no changes in the drug concentration distribution. The method presented gives novel insight into subcutaneous injections of soluble insulin drugs and can be used to optimize the injection technique for subcutaneous drug administration in preclinical studies of rodents.

Towards a Physiological Prandial Insulin Profile: Enhancement of Subcutaneously Injected Prandial Insulin Using Local Warming Devices

The need to develop an insulin delivery system that can closely mimic physiologically induced changes in prandial insulin release has been a major research target since the discovery of insulin. The challenges facing existing insulin delivery systems, related to relatively slow pharmacokinetics and pharmacodynamics, have been further highlighted by rapid advances in diabetes technology and progress in artificial pancreas research. Despite the growing interest in alternative routes of insulin administration, the subcutaneous route remains-at least for now-the preferred route for insulin administration. In this article, we review efforts aimed at developing subcutaneously injected ultrafast-acting insulin and measures aimed at enhancing insulin absorption, focusing on local warming devices.

Dynamic behavior of a spring-powered micronozzle needle-free injector

Conventional injection is still the leading method to deliver macromolecular therapeutics. Needle injection is considered a low compliance administration strategy, principally due to pain and needle phobia. This has fostered the research on the development of alternative strategies to circumvent the skin barrier. Among needle-free drug delivery methods, jet injection is an old strategy with great potential not yet completely disclosed. Here, the design, engineering and dynamic behavior of a novel spring-powered micronozzle needle-free injector is presented. Fluid mechanics was first studied in air to calculate jet force and speed as well as injection duration in different conditions. Polyacrylamide gel was used to simulate a soft tissue and to investigate the jet evolution over time of different injected doses. Finally, ex vivo characterization was carried out on pig skin. Results evidenced a direct dependence of the force, velocity, and duration with the injection volume. The model material allowed individuating the different steps of jet penetration and to attempt a mechanistic explanation. A different behavior has been recorded in the skin with interesting findings for subcutaneous and/or dermal delivery. Peculiar features with respect to existing jet injectors confers to this device good potentiality for a future clinical application.

A patchless dissolving microneedle delivery system enabling rapid and efficient transdermal drug delivery

Dissolving microneedles (DMNs) are polymeric, microscopic needles that deliver encapsulated drugs in a minimally invasive manner. Currently, DMN arrays are superimposed onto patches that facilitate their insertion into skin. However, due to wide variations in skin elasticity and the amount of hair on the skin, the arrays fabricated on the patch are often not completely inserted and large amount of loaded materials are not delivered. Here, we report “Microlancer”, a novel micropillar based system by which patients can self-administer DMNs and which would also be capable of achieving 97 ± 2% delivery efficiency of the loaded drugs regardless of skin type or the amount of hair on the skin in less than a second.

A pilot study to examine the tolerability and device preference in type 1 diabetes of insulin aspart administered by InsuJet compared with subcutaneous injection

BACKGROUND

Jet injectors allow needle-free insulin delivery. The study objective was to compare the tolerability and device preference of subcutaneous insulin aspart delivery by jet injector (InsuJet™; European Pharma Group, Schiphol-Rijk, The Netherlands) with pen injection in an open-label, randomized, crossover pilot study.

SUBJECTS AND METHODS

Ten participants with type 1 diabetes underwent two meal tolerance tests 1 week apart. Plasma glucose and serum insulin levels were sampled from 10 min preceding to 240 min after insulin aspart administration by InsuJet or FlexPen(®) (Novo Nordisk Pharmaceuticals Pty. Ltd., Baulkham Hills, NSW, Australia). Insulin dose was calculated using participants' insulin-to-carbohydrate ratios. Immediately after insulin administration, participants drank 500 mL of Ensure(®) (Abbott Australasia Pty. Ltd., Botany, NSW, Australia) (providing 2,240 kJ of energy, 18.6 g of protein, 96 g of carbohydrate, and 3 g of fat).

RESULTS

In this small pilot study, the devices were similar in glucose excursion (median [quartile 1, quartile 3], InsuJet vs. FlexPen, 9.4 [4.8, 12.8] vs. 8.1 [5.4, 10.6] mmol/L; P=0.43), in the area under the glucose concentration-time curve for 0-240 min corrected for baseline glucose level (InsuJet vs. FlexPen, 1,230 [623, 2,012] vs. 1,175 [91, 1,774] mmol · min/L; P=0.4), and in insulin absorption over the 240-min period. Devices were similar for participant preference and relative injection pain.

CONCLUSIONS

Subcutaneous jet injection of aspart insulin was well tolerated.