Insulin Release from NPH Insulin-Loaded Pluronic® F127 Hydrogel in the Presence of Simulated Tissue Enzyme Activity

Background: Despite the widespread use of newer basal insulins, Natural Protamine Hagedorn (NPH) insulin still represents a well-established basal formulation with its long history of use, featuring the native form of human insulin. However, NPH insulin exhibits an undesirable peak within hours after a single subcutaneous (s.c.) injection, which may lead to hypoglycemia followed by insufficient basal insulin delivery. This may be attributed to the s.c. enzyme activities degrading the protamine in NPH microcrystals. Methods: A thermogelling block copolymer Pluronic® F127 (PF127) was utilized as a protective carrier for NPH microcrystals and as a modulator for insulin release from NPH. NPH insulin-loaded PF127 gel was prepared with varying concentrations of the polymer (15–25%) under mild conditions. The formulations were characterized for their gelling temperature, morphology, gel erosion, and in vitro insulin release, with trypsin concentrations up to 5 U/mL. Results: Scanning electron microscopy (SEM) showed that the integrity of NPH microcrystals was maintained after preparation. The burst release of insulin from NPH was significantly attenuated over the course of ~16h in the presence of PF127 with or without enzyme activity. Conclusion: NPH-PF127 successfully resisted the acceleration of NPH crystal dissolution and insulin release in vitro in the presence of protamine-degrading enzyme activity, warranting further testing.

Successful Treatment with Bedtime Basal Insulin Added to Metformin without Weight Gain or Hypoglycaemia over Three Years

The aim of this observational study was to follow-up patients with bedtime basal insulin (NPH insulin) added to metformin. In 285 patients with type 2 diabetes, a therapy with bedtime basal insulin added to metformin was started due to failure to achieve a glycaemic goal. Up until July 2019, 272 patients (95.4%) were followed-up (59.5 y, 92.6 kg, diabetes duration 6.6 y, HbA1c 8.4%/68.6 mmol/mol). HbA1c decreased by −1.2% and bodyweight by −1.7 kg after a duration of 31.7 ± 29.1 (range 2–133) months. Severe hypoglycaemia did not occur. In 144/272 patients (52.9%), the therapeutic goal for HbA1c was achieved over 32.7 months. In 69/272 patients (25.4%), the HbA1c target was achieved over 25.0 months (afterwards, therapy with basal insulin was discontinued because HbA1c was under target). In 36/272 patients (13.2%), the HbA1c goal was achieved until the submission of this manuscript (mean duration of treatment 57.4 ± 28.2 (range 13–121) months). Over 90% of patients with type 2 diabetes and failure of metformin reached their HbA1c goal with additional basal insulin at bedtime over several years in association with a reduction of bodyweight and without any event of severe hypoglycaemia.

Switching from Neutral Protamine Hagedorn Insulin to Insulin Glargine 300 U/mL Improves Glycaemic Control and Reduces Hypoglycaemia Risk: Results of a Multicentre, Prospective, Observational Study

Type 2 diabetes mellitus (T2DM) is a major cause of morbidity and mortality worldwide and is an important public health issue. A significant proportion of insulin-treated patients with T2DM do not reach target glycated haemoglobin (HbA1c) values, which ultimately increases their risk of long-term microvascular and macrovascular complications. One potential option to improve diabetes control in these patients may be the use of new insulin formulations including second-generation basal insulin analogues such as insulin glargine 300 U/mL (Gla-300). Several published randomised controlled trials have assessed the clinical effectiveness of Gla-300, mostly versus insulin glargine 100 U/mL as well as insulin degludec. However, there is limited information about the real-world effectiveness of Gla-300 when patients are transitioned directly from neutral protamine Hagedorn (NPH) human basal insulin. The primary objective of this study was to evaluate the effectiveness of Gla-300, defined as the percentage of participants with an HbA1c reduction of ≥0.5%, 6 months after switching from NPH insulin, in participants with T2DM. Secondary objectives included the safety assessment based on the percentage of patients experiencing ≥1 episodes and the number of hypoglycaemic episodes by category: severe, symptomatic, symptomatic confirmed, diurnal or nocturnal, change in body weight, and insulin dose. A total of 469 participants completed the 6-month observation period. Mean baseline HbA1c was 9.19%. The percentage of participants with a ≥0.5% improvement in HbA1c from baseline was 71.7% at 6 months. Mean HbA1c decreased at 3 and 6 months by 0.77% (±0.98) and 1.01% (±1.12), respectively (p<0.00001 versus baseline), while fasting glycaemia decreased by 32 mg/dL and 37 mg/dL, respectively (p<0.00001 versus baseline). There were moderate increases in the doses of both Gla-300 and, if used, short-acting insulins during the 6 months of observation. The percentage of participants with ≥1 hypoglycaemia event during the preceding 4 weeks decreased significantly from baseline to 3 and 6 months, as did the proportion with symptomatic hypoglycaemia at night (p<0.00001 versus baseline). No participants had severe hypoglycaemia after a switch to Gla-300. Body mass, waist and hip circumferences, and waist : hip ratio did not change significantly. In conclusion, this large, prospective, observational study demonstrated that switching from NPH insulin to Gla-300 resulted in a significant improvement in HbA1c, with only a moderate increase in insulin dose, a decreased risk of hypoglycaemia, and no increase in body weight.