Biosynthetic Human Insulin and Insulin Analogs.

BACKGROUND: Biosynthetic human insulins and analogs have replaced animal insulins and permitted structural modifications to alter the rate of absorption, duration of action, improve reproducibility of effects, and modulate relative efficacy in various target tissues. Several forms of rapidly acting insulins nearly achieve rapid pharmacokinetics and pharmacodynamics similar to first-phase insulin release. There is need for even faster-acting analogs to mimic normal physiology and improve control of postprandial glycemic excursions. Two biosynthetic insulin analogs have sufficiently long duration of action for use as once-daily basal insulins; controversy persists regarding their respective risks of hypoglycemia and relative glycemic variability. RESULTS: Basal-bolus therapy and insulin pump therapy, including closed-loop automated insulin delivery, require rapid-acting insulin analogs. The longer acting insulins can provide stable, reproducible basal insulin with reduced rates of hypoglycemia, particularly nocturnal hypoglycemia, greater efficacy in reducing mean glucose and glucose variability while increasing time in glucose target range. Inhalable human insulin provides very rapid action. Premixture of rapid-acting analogs with protamine has been useful for some patients with type 2 diabetes. An insulin analog with preferential efficacy at the liver has been developed and tested clinically but not marketed. Current research is aimed at developing even faster-acting insulin analogs. Long-acting basal insulins coformulated with GLP-1 receptor agonists or with a rapidly acting insulin analog have valuable clinical applications. Excipients, chaperones, local heating of the infusion site, and hyaluronidase have also been used to accelerate the absorption of insulin analogs. CONCLUSIONS: Biosynthetic human insulins have radically revolutionized management of both type 1 and type 2 diabetes worldwide. The ability to manipulate the structure and formulation of insulin provides for more physiologic pharmacokinetics and pharmacodynamics, enabling improved glycemic control, reduced risk of hypoglycemia, and reduced rates of long-term complications.

Efficacy of Topical Insulin Therapy for Chronic Trophic Ulcers in Patients with Leprosy: A Randomized Interventional Pilot Study.

BACKGROUND: Chronic trophic ulcers (CTUs), especially those located over the plantar region, are a leading cause of deformity and disability in patients with leprosy. Despite the various treatment modalities available, CTUs can be chronic and refractory to treatment. The successful use of topical insulin in various types of wounds led researchers to evaluate its safety and efficacy in the treatment of plantar CTUs. METHODS: Forty-two patients who had completed a multidrug treatment for leprosy were recruited and randomized into two groups. In the test group, 23 patients received 10 units (0.1 mL) of topical insulin (Actrapid) in 1 mL of normal saline twice daily over treated areas. The placebo group (n = 19) received topical normal saline only. The primary end point was the proportion of patients with complete wound closure by 12 weeks. Secondary end points included time to healing, wound area reduction, Physician Global Assessment of Efficacy scores, and Dermatology Life Quality Index scores at the end of 12 weeks. RESULTS: The majority of CTUs (80%) were situated over the forefoot; the metatarsal head of the hallux was the most common site (86%). Wound healing was faster (0.61 ± 0.31 vs 0.14 ± 0.42 cm per week, P < .0001), and the number of days to complete healing was significantly shorter in the test group compared with the placebo group (31.5 ± 17.6 vs 44.3 ± 16.2 days, P = .02). The only observed adverse effect in the test group was white granular deposits over the CTU (n = 10). CONCLUSIONS: Topical insulin therapy may be a safe, efficacious, cheap, and easily available treatment option in CTUs among patients with leprosy.

Oral insulin does not alter gut microbiota composition of NOD mice.

BACKGROUND: Oral insulin as a preventive strategy and/or treatment of type 1 diabetes has been the target of much research. Producing oral insulins is a complex and challenging task, with numerous pitfalls, due to physiological, physical, and biochemical barriers. Our aim was to determine the impact of oral insulin on the delicate gut microbiota composition. METHODS: Female nonobese diabetic mice were given oral porcine insulin 2 times a week from 5 weeks of age for 4 weeks, and then subsequently once a week for 21 weeks, or until euthanized. The mice were divided into groups on a gluten-reduced diet or a standard diet. Gut microbiota composition was analysed based on faecal samples, and the type 1 diabetes incidence of the mice was monitored. RESULTS: We observed no influence of the oral porcine insulin on the gut microbiota composition of mice on a gluten-reduced or a standard diet at 9 weeks of age. Also, the administration of oral insulin did not influence the incidence of type 1 diabetes at 30 weeks of age. CONCLUSIONS: Oral porcine insulin does not alter the gut microbiota composition of nonobese diabetic mice on either a gluten-reduced diet or standard diet. Also, the oral porcine insulin did not influence the incidence of type 1 diabetes in the groups.

Evaluation of NovoRapid infusion as a treatment option in the management of diabetic ketoacidosis.

This study evaluates the clinical efficacy and safety of NovoRapid (insulin aspart) compared to Actrapid™ (human neutral insulin) for diabetic ketoacidosis (DKA). In this retrospective study involving 40 patients, no statistically significant differences were observed between biochemical variables, infusion duration or complications in patients treated with insulin aspart or human neutral insulin. These results support the use of insulin aspart as an effective and safe alternative to human neutral insulin in DKA.

Alternative approach to the treatment of diabetes mellitus.

The influence of insulin preparations (Actrapid and Ransulin) on the glucose and insulin blood level has been studied in patients with diabetes mellitus. It has been shown that comparable changes in the measured parameters are achieved in most patients with oral doses of Ransulin that are two to three times higher than the doses of Actrapid.

Improved glycemic control and acute complications among children with type 1 diabetes mellitus in Moshi, Tanzania.

OBJECTIVE: There are an estimated 1000 children with diabetes in Tanzania. Recently, the first two pediatric endocrinologists, trained in the European Society for Paediatric Endocrinology (ESPE)/International Society for Paediatric and Adolescent Diabetes (ISPAD) program in Nairobi, Kenya, entered practice. The purpose of this study was to prospectively assess the impact of a 6-month diabetes management and education program on glycemic control and acute complications in children and adolescents in Tanzania. RESEARCH DESIGN AND METHODS: Eighty-one patients aged 3-19 yr were enrolled. All were on split-dose Insulatard (Neutral Protamine Hagedorn) and Actrapid (soluble, regular) insulin, and were given three glucose test strips per week. Children were seen in clinic an average of six times over 6 months and received 3 h of diabetes education. A structured questionnaire evaluated social demographic data and acute complications. RESULTS: Despite regular clinic attendance, diabetes education, and provision of insulin, hemoglobin A1c (HbA1c) levels did not improve. Four children (5%) had HbA1c 7.5%, 22 (28%) HbA1c 7.5-10%, 9 (24%) HbA1c 11-12.5%, and 36 (44%) HbA1c >12.5%. There was a substantial reduction in severe hypoglycemia, with 17% of subjects experiencing this acute complication compared to 52% in the 6 months prior to study enrolment. Six children were admitted in diabetic ketoacidosis during the study compared to three during the previous 6 months. Twenty-six children (36%) reported missing >6 doses of insulin (but only two lacked insulin). CONCLUSIONS: Diabetes education significantly reduced the risk of severe hypoglycemia, but better glycemic control of diabetes was not attained. Further study is needed to explore factors to improve glycemic control including increased testing, or perhaps different insulin regimens.

Single-injection HPLC method for rapid analysis of a combination drug delivery system.

Developing combination drug delivery systems (CDDS) is a challenging but necessary task to meet the needs of complex therapy regimes for patients. As the number of multi-drug regimens being administered increases, so does the difficulty of characterizing the CDDS as a whole. We present a single-step method for quantifying three model therapeutics released from a model hydrogel scaffold using high-performance liquid chromatography (HPLC). Poly(ethylene glycol) dimethacrylate (PEGDMA) hydrogel tablets were fabricated via photoinitiated crosslinking and subsequently loaded with model active pharmaceutical ingredients (APIs), namely, porcine insulin (PI), fluorescein isothiocyanate-labeled bovine serum albumin (FBSA), prednisone (PSE), or a combination of all three. The hydrogel tablets were placed into release chambers and sampled over 21 days, and APIs were quantified using the method described herein. Six compounds were isolated and quantified in total. Release kinetics based on chemical properties of the APIs did not give systematic relationships; however, PSE was found to have improved device loading versus PI and FBSA. Rapid analysis of three model APIs released from a PEGDMA CDDS was achieved with a direct, single-injection HPLC method. Development of CDDS platforms is posited to benefit from such analytical approaches, potentially affording innovative solutions to complex disease states.

A Nanocomposite Vehicle Based on Metal-Organic Framework Nanoparticle Incorporated Biodegradable Microspheres for Enhanced Oral Insulin Delivery.

Oral insulin delivery has revolutionized diabetes treatment, but challenges including degradation in the gastrointestinal environment and low permeation across the intestinal epithelium remain. Herein, to overcome these barriers, we developed a novel biodegradable nanocomposite microsphere embedded with metal-organic framework (MOF) nanoparticles. An iron-based MOF nanoparticle (NP) (MIL-100) was first synthesized as a carrier with an insulin loading capacity of 35%. The insulin-loaded MIL-100 nanoparticles modified with sodium dodecyl sulfate (Ins@MIL100/SDS) promoted insulin permeation across Caco-2 monolayer models in vitro. To improve resistance to the gastric acid environment, Ins@MIL100/SDS nanoparticles were embedded into a biodegradable microsphere to construct the nanocomposite delivery system (Ins@MIL100/SDS@MS). The microspheres effectively protected the MOF NPs from rapid degradation under acidic conditions and could release insulin-loaded MOF NPs in the simulated intestinal fluid. After the oral administration of Ins@MIL100/SDS@MS into BALB/c nude mice, increased intestinal absorption of the insulin was detected compared to the oral administration of free insulin or Ins@MIL100/SDS. Furthermore, significantly enhanced plasma insulin levels were obtained for over 6 h after oral administration of Ins@MIL100/SDS@MS into diabetic rats, leading to a remarkably enhanced effect in lowering blood glucose level with a relative pharmacological availability of 7.8%. Thus, the MOF-nanoparticle-incorporated microsphere may provide a new strategy for effective oral protein delivery.

Transient neonatal diabetes mellitus and activating mutation in the KCNJ11 gene in two siblings.

Transient neonatal diabetes mellitus is a rare disease usually associated with chromosome 6 abnormalities. Mutations of the genes encoding the potassium channel are rarely associated with these transitional forms. Herein, we report the clinical features of two siblings with a heterozygous mutation C679 G>A in the KCNJ11 gene.

A case of hypersensitivity to soluble and isophane insulins but not to insulin glargine.

Insulin is an important agent for the treatment of diabetes mellitus (DM). Allergic reactions to insulin therapy, although rare, have been evident since animal insulin became available for the treatment of DM in 1922. Hypersensitivity to insulin has considerably been reduced with the introduction of human insulin produced by recombinant deoxyribonucleic acid technology. Here, we present a case of Type 2 DM who demonstrated immediate (Type 1) hypersensitivity reaction on the sites of subcutaneous injection of soluble and isophane insulin but insulin glargine was tolerated well and provided good glycemic control.

Modest hyperglycemia prevents interstitial dispersion of insulin in skeletal muscle.

UNLABELLED: Insulin injected directly into skeletal muscle diffuses rapidly through the interstitial space to cause glucose uptake, but this is blocked in insulin resistance. As glucotoxicity is associated with endothelial dysfunction, the observed hyperglycemia in diet-induced obese dogs may inhibit insulin access to muscle cells, and exacerbate insulin resistance. Here we asked whether interstitial insulin diffusion is reduced in modest hyperglycemia, similar to that induced by a high fat diet. METHODS: During normoglycemic (100 mg/dl) and moderately hyperglycemic (120 mg/dl) clamps in anesthetized canines, sequential doses of insulin were injected into the vastus medialis of one hindlimb; the contra-lateral limb served as a control. Plasma samples were collected and analyzed for insulin content. Lymph vessels of the hind leg were also catheterized, and lymph samples were analyzed as an indicator of interstitial insulin concentration. RESULTS: Insulin injection increased lymph insulin in normoglycemic animals, but not in hyperglycemic animals. Muscle glucose uptake was elevated in response to hyperglycemia, however the insulin-mediated glucose uptake in normoglycemic controls was not observed in hyperglycemia. Modest hyperglycemia prevented intra-muscularly injected insulin from diffusing through the interstitial space reduced insulin-mediated glucose uptake. CONCLUSION: Hyperglycemia prevents the appearance of injected insulin in the interstitial space, thus reducing insulin action on skeletal muscle cells.

Effect of force of microneedle insertion on the permeability of insulin in skin.

Many experiments conducted in the literature have investigated the effect of microneedles (MNs) on insulin permeation across skin. There are also a number of articles that deal with the effect of MN insertion force in skin. However, there is little known on quantifying the relationship between the effect of MN insertion force and the amount of insulin permeated for given MNs. This issue is addressed in this article. MNs of 1100 µm and 1400 µm are used to conduct in vitro permeability experiments on porcine skin, using insulin. Histological images of MN treated skin are obtained from a microtome and the viscoelastic properties of the skin sample are measured using a rheometer. An in-house insertion force device is utilized that can reproducibly apply a specified force on MNs for a set period of time using compressed air. It is deduced that when porcine skin was pretreated with an applied force of 60.5 N and 69.1 N, the resultant amount of insulin permeated was approximately 3 µg and 25 µg over a 4-hour period for the MNs used. The amount of MN force applied to porcine skin was shown to be related to the amount of insulin permeated. An increase in insertion force increase the amount of insulin permeated. It was also demonstrated that using insufficient force may have reduced or prevented the amount of insulin passing through the skin, regardless of the geometry of the MNs.

Dissolving polymeric microneedle arrays for electrically assisted transdermal drug delivery.

It has recently been proposed that the combination of skin barrier impairment using microneedles (MNs) coupled with iontophoresis (ITP) may broaden the range of drugs suitable for transdermal delivery, as well as enabling the rate of delivery to be achieved with precise electronic control. However, no reports exist on the combination of ITP with in situ drug loaded polymeric MN delivery systems. Furthermore, although a number of studies have highlighted the importance of MN design for transdermal drug delivery enhancement, to date, there has been no systematic investigation of the influence of MN geometry on the performance of polymeric MN arrays which are designed to remain in contact with the skin during the period of drug delivery. As such, for the first time, this study reports on the effect of MN heigth and MN density upon the transdermal delivery of small hydrophilic compounds (theophylline, methylene blue, and fluorescein sodium) across neonatal porcine skin in vitro, with the optimised MN array design evaluated for its potential in the electrically faciliatated delivery of peptide (bovine insulin) and protein (fluorescein isothiocyanate-labelled bovine serum albumin (FTIC-BSA)) macromolecules. The results of the in vitro drug release investigations revealed that the extent of transdermal delivery was dependent upon the design of the MN array employed, whereby an increase in MN height and an increase in MN density led to an increase in the extent of transdermal drug delivery achieved 6h after MN application. Overall, the in vitro permeation studies revealed that the MN design containing 361 MNs/cm(2) of 600 µm height resulted in the greatest extent of transdermal drug delivery. As such, this design was evaluated for its potential in the MN mediated iontophoretic transdermal delivery. Whilst the combination of MN and ITP did not further enhance the extent of small molecular weight solute delivery, the extent of peptide/protein release was significantly enhanced when ITP was used in combination of the soluble PMVE/MA MN arrays. For example, the cumulative amount of insulin permeated across neonatal porcine skin at 6h was found to be approximately 150 µg (3.25%), 227 µg (4.85%) and 462 µg (9.87%) for ITP, MN, and MN/ITP delivery strategies, respectively. Similarly, the cumulative amount of FTIC-BSA delivered across neonatal porcine skin after a 6h period was found to be approximately 110 µg (4.53%) for MN alone and 326 µg (13.40%) for MN in combination with anodal ITP (p<0.001). As such, drug loaded soluble PMVE/MA MN arrays show promise for the electrically controlled transdermal delivery of biomacromolecules in a simple, one-step approach.