Background and aim: In 2019, the Italian Society of Diabetology and the Italian Association of Clinical Diabetologists nominated an expert panel to develop guidelines for drug treatment of type 2 diabetes. This expert panel, after identifying the effects of glucose-lowering agents on major adverse cardiovascular events (MACEs) and all-cause mortality as critical outcomes, decided to perform a systematic review and meta-analysis on the effect of insulin secretagogues (sulfonylureas and glinides) with this respect.

Methods and results: A MEDLINE database search was performed to identify all RCTs, up to January 1st, 2020, with duration≥52 weeks, in which insulin secretagogues (glibenclamide, gliclazide, glimepiride, glipizide, chlorpropamide, repaglinide, nateglinide) were compared with either placebo or active comparators. The principal endpoints were MACE (restricted for RCT reporting MACEs within their outcomes) and all-cause mortality (irrespective of the inclusion of MACEs among the pre-specified outcomes). Mantel-Haenszel odds ratio (MH-OR) with 95% Confidence Interval (95% CI) was calculated for all the endpoints considered. Fourteen RCTs were included in the analysis for MACEs (919 in insulin secretagogues and 1,087 in control group). Insulin secretagogues were not significantly associated with an increased risk of MACEs in comparison with controls (MH-OR 1.08 [95% CI 0.96, 1.22], p = 0.20). When considering the 48 RCTs fulfilling criteria for inclusion in the analysis on all-cause mortality, insulin secretagogues were associated with a significantly increased risk of all-cause mortality (MH-OR 1.11 [1.00, 1.23], p = 0.04).

Conclusions: This meta-analysis suggests that insulin secretagogues are associated with an increased risk of all-cause mortality when compared with placebo or other anti-hyperglycaemic drugs.

Keywords: Insulin secretagogues; Major cardiovascular events; Metanalysis; Mortality; Type 2 diabetes.

Objective: To estimate using the UK Prospective Diabetes Study Outcomes Model Version 2 (UKPDS-OM2) the impact of delaying type 2 diabetes onset on costs and quality-adjusted life expectancy using trial participants who developed diabetes in the NAVIGATOR (Nateglinide And Valsartan in Impaired Glucose Tolerance Outcomes Research) study.

Research design and methods: We simulated the impact of delaying diabetes onset by 1-9 years, utilizing data from the 3,058 of 9,306 NAVIGATOR trial participants who developed type 2 diabetes. Costs and utility weights associated with diabetes and diabetes-related complications were obtained for the U.S. and U.K. settings, with costs expressed in 2017 values. We estimated discounted lifetime costs and quality-adjusted life years (QALYs) with 95% CIs.

Results: Gains in QALYs increased from 0.02 (U.S. setting, 95% CI 0.01, 0.03) to 0.15 (U.S. setting, 95% CI 0.10, 0.21) as the imposed time to diabetes onset was increased from 1 to 9 years, respectively. Savings in complication costs increased from $1,388 (95% CI $1,092, $1,669) for a 1-year delay to $8,437 (95% CI $6,611, $10,197) for a delay of 9 years. Interventions costing up to $567-$2,680 and £201-£947 per year would be cost-effective at $100,000 per QALY and £20,000 per QALY thresholds in the U.S. and U.K., respectively, as the modeled delay in diabetes onset was increased from 1 to 9 years.

Conclusions: Simulating a hypothetical diabetes-delaying intervention provides guidance concerning the maximum cost and minimum delay in diabetes onset needed to be cost-effective. These results can inform the ongoing debate about diabetes prevention strategies and the design of future intervention studies.

A validated method for preconcentration and determination of nateglinide in plasma was developed using vortex-assisted dispersive liquid-liquid microextraction. Different variables that affect extraction efficiency were studied and optimized, including type and volume of extractant, type and volume of disperser, pH of diluent, salt addition effect, centrifugation and vortex time. Nateglinide was extracted using 30 μL of 1-octanol as an extractant and 200 μL of methanol as a disperser. The enrichment factor reached 330 under the optimum conditions. High-performance liquid chromatography/ultraviolet was used for detection using phosphate buffer (pH 2.5, 10 mM): acetonitrile (45:55, v/v) as a mobile phase at a flow rate of 1 mL/min. The method was linear over the range of 50-20,000 ng/mL with a limit of detection of 15 ng/mL (signal-to-noise ratio = 3). Intra- and inter-day precision had %relative standard deviation <6% (n = 3) and the %recoveries were found to be between 102.5 and 105.9%. The proposed method is simple, sensitive, eco-friendly, cost-effective and powerful for microextraction of nateglinide from human plasma samples.

Objective: The aim of this work was to investigate dry co-grinding of nateglinide with meglumine for enhanced dissolution rate of nateglinide. The study was extended to investigate the effect of this dissolution enhancement on the hypoglycemic effect of the drug in diabetic rats. Methods: Nateglinide was subjected to dry co-grinding with increasing proportions of meglumine to prepare products containing the drug with meglumine at 1:1, 1:2 and 1:3 molar ratios. These products were evaluated using combined instrumental analysis which employed Fourier infrared spectroscopy (FTIR), differential thermal analysis (DTA) and X-ray diffraction (XRD). Drug dissolution was also monitored before and after processing with and without meglumine. The optimum ratio was used to assess the effect of dissolution enhancement on the hypoglycemic effect of nateglinide on diabetic rats. The unprocessed nateglinide was used as control. Results: Co-grinding of nateglinide resulted in changes in the FTIR spectral patterns of nateglinide and meglumine. The changes suggested the formation of amide bond between both compounds at 1:1 molar ratio. The new species was confirmed by DTA and XRD. This species exhibited fast dissolution of nateglinede after incorporation of higher proportions of meglumine. Co-grinding was essential as indicated from slower dissolution from physical mixture containing the highest proportion of meglumine. Enhanced dissolution was reflected in vivo as improved rate and extent of hypoglycemia. Conclusion: Dry co-grinding of nateglinide with meglumine developed new species which liberated nateglinide rapidly and enhanced the rate and extent of hypoglycemia of nateglinide.

Keywords: Nateglinide; dissolution rate; hypoglycemic effect; meglumine; salt formation.

Background: Diabetes is a global disease with rapidly increasing prevalence in the world. Glycated hemoglobin (HbA1c) as an important indicator of diabetes could reflect the average serum glucose level over 120 days. However, when using HbA1c to diagnose diabetes, it is important to consider other factors that may impact HbA1c level including age, race/ethnicity, detection method, and co-morbidities. Here we report a case of diabetes with normal hemoglobin but reduced HbA1c. Case report: A 57-year-old female patient was diagnosed with diabetes by oral glucose tolerance test results. However, the HbA1c level was repeatedly decreased, glycated albumin level was high, with normal levels of hemoglobin and albumin, and a slightly elevated level of bilirubin. Moreover, life span of red blood cells was significantly shortened. Further examination of whole exome sequencing of the patient and her daughter showed heterozygous variant in PIEZO1 gene (c.6017T > A) in both, which is associated with dehydration hereditary stomatocytosis (DHS). After this diagnosis, we changed nateglinide to sitagliptin to reduce the burden of the pancreas islet function. Conclusion: In case of abnormally low HbA1c, we recommend that GA and reticulocyte should be measured simultaneously. Moreover, the methodology for hemoglobin measurement and the diseases that could cause abnormal quantity and quality of red blood cells and hemoglobin be considered.

Keywords: PIEZO1 gene; diabetes; glycated albumin; glycated hemoglobin; hemolytic anemia.

Serious hypoglycemia is a major adverse event associated with insulin secretagogues. Previous studies have suggested a potential relationship between angiotensin-converting enzyme inhibitors (ACEIs) used with sulfonylureas and serious hypoglycemia, and widely used drug compendia warn of this potential drug-drug interaction. We investigated the association between serious hypoglycemia and concomitant use of ACEIs in patients receiving insulin secretagogues, using the self-controlled case series design and Medicaid claims data from 5 US states linked to Medicare claims from 1999-2011. The exposure of interest was active prescription for ACEIs during insulin secretagogue or metformin (negative control object drug) episodes. The outcome was hospital presentation for serious hypoglycemia, identified by discharge diagnosis codes in inpatient and emergency department claims (positive predictive value ~78-89%). We calculated confounder-adjusted rate ratios (RRs) and 95% confidence internals (CIs) of outcome occurrence during ACEI-exposed versus ACEI-unexposed time using conditional Poisson regression. The RRs for ACEIs were not statistically elevated during observation time of glipizide (RR, 1.06; CI, 0.98-1.15), glyburide (RR, 1.05; CI, 0.96-1.15), repaglinide (RR, 1.15; CI, 0.94-1.41), or metformin (RR, 1.02; CI, 0.97-1.06); but was modestly elevated with glimepiride (RR, 1.23; CI, 1.11-1.37) and modestly reduced with nateglinide (RR, 0.73; CI, 0.56-0.96). The overall pattern of results do not suggest that ACEIs used with insulin secretagogues were associated with increased rates of serious hypoglycemia, with the possible exception of glimepiride.

Keywords: Medicaid; angiotensin-converting enzyme inhibitors; drug-drug interaction; insulin secretagogues; metformin; pharmacoepidemiology; serious hypoglycemia; sulfonylureas.

Background: Genetic polymorphisms in the PPARD and NOS1AP is associated with type 2 diabetes mellitus (T2DM); however, there is no evidence about its impact on the therapeutic efficacy of nateglinide. This study was designed to investigate a potential association of PPARD rs2016520 (T/C) and NOS1AP rs12742393 (A/C) polymorphisms with efficacy of nateglinide in newly diagnosed Chinese patients with type 2 diabetes mellitus (T2DM).

Methods: Sixty patients with newly diagnosed T2DM were enrolled to identify PPARD rs2016520 and NOS1AP rs12742393 genotypes using the polymerase chain reaction-restriction fragment length polymorphism assay (PCR-RFLP). All subjects were treated with nateglinide (360 mg/day) for 8 weeks. Anthropometric measurements, clinical laboratory tests were obtained at baseline and after 8 weeks of nateglinide treatment.

Results: After nateglinide treatment for 8 consecutive weeks, patients with at least one C allele of PPARD rs2016520 showed a smaller decrease in post plasma glucose (PPG), homeostasis model assessment for beta cell function (HOMA-B) than those with the TT genotype did (P < 0.05). In patients with the AA genotype of NOS1AP rs12742393, the drug showed better efficacy with respect to levels of fasting plasma glucose (FPG), fasting serum insulin (FINS), HOMA-B and homeostasis model assessment for insulin resistance (HOMA-IR) than in patients with the AC + CC genotype (P < 0.05). NOS1AP rs12742393 genotype distribution and allele frequency were associated with responsiveness of nateglinide treatment (P < 0.05).

Conclusions: The PPARD rs2016520 and NOS1AP rs12742393 polymorphisms were associated with nateglinide monotherapy efficacy in Chinese patients with newly diagnosed T2DM.

Trial registration: Chinese Clinical Trial Register ChiCTR13003536, date of registration: May 14, 2013.

Keywords: Genetic polymorphism; NOS1AP; Nateglinide; PPARD; Type 2 diabetes mellitus.

Repaglinide is a drug used in the treatment of diabetes mellitus type 2. It belongs to a class of antihyperglycemic agents known as meglitinides, along with nateglinide. Meglitinides work to reduce blood glucose levels by stimulating endogenous insulin production. The present recommended starting dose is dependent on hemoglobin A1c levels, with those below 8% (64 mmol/mol) urged to start with 0.5mg pre-prandially, and those above 8% to start with 1 to 2mg.

Meglitinides are a group of oral hypoglycemic medications currently approved for the treatment of type 2 diabetes mellitus (T2DM). Two meglitinide molecules, Repaglinide and Nateglinide,are presently in use. Repaglinide is preferred because of its superior glycemic efficacy.They have modest efficacy with a mean decrement of glycosylated haemoglobin (HbA1c) ranging between -0.2 to -1.50% with individual therapy. Additional HbA1c reduction can occur with combination therapy with other oral hypoglycemics. This class of drugs is effective in controlling postprandial hyperglycemia with minimal risk of hypoglycemia.It is also useful in patients in with variable meal timings, especially in the elderly, and in patients with renal failure. There are is a dearth of long-term studies on meglitinides to assess cardiovascular outcomes or mortality in T2DM,although the Nateglinide and Valsartan in Impaired Glucose ToleranceOutcomes Research (NAVIGATOR) study showed no difference between Nateglinide and placebo with regard to the core composite cardiovascular outcomes. Based on a PubMed literature search using key words: 'meglitinides', 'repaglinide', 'nateglinide', 'HbA1c', 'glycated haemoglobin', 'cardiovascular safety', 'cardiovascular events', 'cardiovascular outcome trials', 'type 2 diabetes mellitus' and heart failure, and combining the search terms using Boolean operators 'AND', 'OR' and 'NOT' as needed we compiled current evidence for use of these oral hypoglycemic agents in clinical use. This article is an attempt to review the efficacy and cardiovascular (CV) safety of Meglitinides to help clinicians to use this class of oral hypoglycaemic agents prudently.

Keywords: Meglitinides; Nateglinide; cardiovascular outcome trial (CVOT); heart failure; repaglinide; type 2 diabetes mellitus(T2DM)..

The effects of inflammation on hypoglycemic agents were evaluated in male rats with acute peripheral inflammation (API). Nateglinide (NTG) was utilized as a model compound, since it is a hepatically-metabolized compound and its metabolism is mainly mediated by CYP 2C11 enzyme. In the experiments, rats were subjected to carrageenan injection into their hind paws for API induction, and the plasma concentration profiles of NTG were then examined. In addition, pooled liver microsomes were prepared from control and API rats, and the hepatic drug-metabolizing activity toward NTG and the hepatic expression of CYP2C11 protein were evaluated. It was shown that the plasma concentration of NTG following its intravenous administration decreases at a slower rate in API rats than that in control rats. It was also indicated in the incubation study with the liver microsomes that the hepatic drug-metabolizing activity toward NTG decreases in API rats. Additionally, it was revealed in Western immunoblotting that the hepatic expression of CYP2C11 protein decreases in API rats. These findings suggest that inflammation occurring in peripheral tissues brings about a decrease in hepatic NTG metabolism by suppressing the hepatic expression of CYP2C11 protein, causing an alteration of the plasma concentration profile of NTG with its impaired elimination.

Keywords: CYP2C11; acute inflammation; hepatic drug metabolism; nateglinide.

Introduction: Nateglinide or N-(trans-4-isopropylcyclohexyl-1-carbonyl)-D-phenylalanine is a drug with a rapid hypoglycemic effect that is mainly used in the treatment of type 2 diabetes. Very few studies have assessed bioequivalence based on feeding status. This study aimed to assess the pharmacokinetic bioequivalence and safety of nateglinide-containing tablets (0.12 g) in healthy Chinese volunteers under fasting and fed conditions.

Methods: The studies were performed in 2017-2018 in the Phase I Clinical Trial Ward of the Affiliated Hospital of Liaoning University of Traditional Chinese Medicine, China. Eligible Chinese volunteers received a single 0.12-g dose of the test or reference formulation, followed by a 7-day washout period and administration of the alternate formulation. Blood samples were collected at various time intervals, and plasma nateglinide concentrations were analyzed by liquid chromatography-tandem mass spectrometry. Then, the adverse events, laboratory test results, vital signs, and physical exam findings were compared between the 2 groups.

Results: The ratios of the geometric means of Cmax, AUC0-t, and AUC0-inf of the tested to reference preparations under fasting conditions were 105.03% (90% confidence interval [CI]: 99.53-110.83%), 104.02% (90% CI: 101.37-106.74%), and 104.04% (90% CI: 101.38-106.77%), respectively. The same ratios under fed conditions were 96.55% (90% CI: 85.80-108.65%), 103.08% (90% CI: 100.07-106.18%), and 103.07% (90% CI: 100.21-106.01%), respectively. The 90% CI values for Cmax, AUC0-t, and AUC0-inf fell within the accepted range of bioequivalence (80.00-125.0%). Common adverse events included hypoglycemia, heart rate increase, palpitation, sweating, dizziness, and diarrhea.

Conclusions: The test formulation (0.12 g) met the CFDA's regulatory definition for bioequivalence to the reference formulation. Both formulations were well tolerated by healthy Chinese subjects.

Trial registration: This trial has been registered in the Chinese Clinical trial registry (ChiCTR2000030694), March 10, 2020.

Keywords: Bioequivalence; Hypoglycemic effect; Liquid chromatography-tandem mass spectrometry; Nateglinide; Pharmacokinetics.

Genetic polymorphisms in the MTNR1B gene is associated with type 2 diabetes mellitus (T2DM); however, there is no evidence about its impact on the therapeutic efficacy of nateglinide. This prospective case-control study was designed to investigate the effect of MTNR1B rs10830963 gene variant on the therapeutic efficacy of nateglinide in treating T2DM. We genotyped untreated T2DM patients (N = 200) and healthy controls (N = 200) using the method of the high resolution of melting curve (HRM). Newly diagnosed T2DM patients (n = 60) with CYP2C9*1 and SLCO1B1 521TT genotypes were enrolled and given oral nateglinide (360 mg/d) for 8 weeks. The outcome was measured by collecting the venous blood samples before and at the 8th week of the treatment. The risk G allelic frequency of MTNR1B rs10830963 was higher in T2DM patients than the healthy subjects (P < 0.05). Post 8-week of treatment, newly diagnosed T2DM patients showed a less reduction in fasting plasma glucose levels and less increase in the carriers of genotype CG + GG at rs10830963 when compared with the CC genotype (P < 0.05). MTNR1B rs10830963 polymorphism was associated with the therapeutic efficacy of nateglinide in T2DM patients. Also, the CC homozygotes had a better effect than G allele carriers.Trial registration Chinese Clinical Trial Register ChiCTR13003536, date of registration: May 14, 2013.

Keywords: Genetic variant; MTNR1B rs10830963; Nateglinide; Type 2 diabetes.

Selective and straightforward kinetic spectrophotometric methods were developed to quantify nateglinide (NTG) in pharmaceutical dosage forms. Fixed time (ΔA) and the equilibrium methods utilized the reaction of NTG with 1-chloro-2,4-dinitrobenzene (CDNB) in dimethyl sulfoxide (DMSO) with heating at 80 °C for 25 min to form a stable yellow-coloured Meisenheimer complex, which absorbs maximally at 421 nm. The optimization was achieved by utilizing the Box-Behnken experimental design (BBD) combined with response surface methodology (RSM). In which three significant factors were studied, namely, CDNB volume (A), heating temperature (B) and heating time (C) against the absorbance as a response. Method validation presented the International Conference on Harmonisation (ICH) parameters such as specificity, selectivity, linearity, precision, accuracy, limit of detection (LOD), limit of quantitation (LOQ), robustness and solution stability. The LOD and LOQ values were 0.48, 1.46, and 0.21, 0.62 µg/ml, respectively, for a fixed time (ΔA) and equilibrium methods with the linear dynamic range of 1-15 µg/ml. Furthermore, Youden's robustness test using factorial combinations of the selected analytical parameters was performed and investigated its influence with alternative conditions. All results were reproducible and quickly adopted for routine analysis of NTG in pharmaceutical formulations and laboratory preparations.

Keywords: Box–Behnken design; Kinetic spectrophotometry; Method development; Nateglinide; Pharmaceutical formulations; Response surface methodology; Validation.

During diabetes human serum albumin (HSA), an important drug transport protein, can be modified by agents such as glyoxal (Go) and methylglyoxal (MGo) to form advanced glycation end-products. High-performance affinity microcolumns and zonal elution competition studies were used to compare interactions by the anti-diabetic drugs repaglinide and nateglinide with normal and Go- or MGo-modified HSA at Sudlow sites I and II of this protein. Both drugs had their strongest binding at Sudlow site II for the normal and modified forms of HSA. The association equilibrium constants at this site for repaglinide and nateglinide with normal HSA were 6.1 (± 0.2) × 10⁴ M^-1 and 7.1 (± 0.8) × 10⁵ M^-1, respectively, at pH 7.4 and 37⁰C; these values increased by up to 3.6-fold for repaglinide and decreased by up to 45-55 % for nateglinide when HSA was modified by Go or MGo at levels seen in prediabetes or diabetes. Both drugs were also found to bind at Sudlow site I, with association equilibrium constants at this site on normal HSA of 4.2 (± 0.3) × 10⁴ M^-1 for repaglinide and 5.0 (± 0.1) × 10⁴ M^-1 for nateglinide. The binding strength for repaglinide at Sudlow site I increased by 1.3- to 1.7-fold with the Go-modified HSA and decreased slightly (i.e., up to 19 %) for the MGo-modified HSA, while nateglinide showed only a small or insignificant change in binding with the same modified HSA samples. These results indicated that binding by repaglinide and nateglinide with HSA can be altered significantly by modification of this protein with Go or MGo, making these modifications of potential interest in the treatment of patients with these drugs during diabetes.

Keywords: Advanced glycation end-products; Drug-protein binding; High-performance affinity chromatography; Human serum albumin; Nateglinide; Repaglinide.

Purpose: Available data on the effects of anti-diabetic drugs on fracture risk are contradictory. Therefore, our study aimed to analyze all available data on the effects of anti-diabetic drugs on fracture risk in type 2 diabetes mellitus (T2DM) patients.

Methods: Embase, Medline, ClinicalTrials.gov, and Cochrane CENTRAL were searched for relevant trials. All data analyses were performed with STATA (12.0) and R language (3.6.0). Risk ratio (RR) with its 95% confidence interval (CI) was calculated by combining data for the fracture effects of anti-diabetic drugs, including sodium-glucose co-transporter 2 (SGLT2) inhibitors, dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide-1 (GLP-1) receptor agonists, meglitinides, α-glucosidase inhibitors, thiazolidinediones, biguanides, insulin, and sulfonylureas.

Results: One hundred seventeen eligible randomized controlled trials (RCTs) with 221,364 participants were included in this study. Compared with placebo, trelagliptin (RR 3.51; 1.58-13.70) increased the risk of fracture, whereas albiglutide (RR 0.29; 0.04-0.93) and voglibose (RR 0.03; 0-0.11) decreased the risk of fracture. Other medications were comparable in terms of their effects on fracture risk, and no statistical significance was observed. In terms of fractures, voglibose (0.01%) may be the safest option, and trelagliptin (13.64%) may be the worst. Sensitivity analysis results were consistent with those of the main analysis. No statistically significant differences were observed in the regression coefficients of age (1.03; 0.32-2.1), follow-up duration (0.79; 0.27-1.64), and sex distribution (0.63; 0.15-1.56).

Conclusions: We found varied results on the association between the use of anti-diabetic drugs and fracture risk. Specifically, trelagliptin raised the risk of fracture, whereas voglibose and albiglutide showed benefit with statistical difference. Other drugs were comparable in terms of their effects on fracture risk. Some drugs (omarigliptin, sitagliptin, vildagliptin, saxagliptin, empagliflozin, ertugliflozin, rosiglitazone, pioglitazone, and nateglinide) may increase the risk of fracture, while others (such as dulaglutide, exenatide, liraglutide, semaglutide, lixisenatide, linagliptin, alogliptin, canagliflozin, dapagliflozin, glipizide, gliclazide, glibenclamide, glimepiride, metformin, and insulin) may show benefits. The risk of fracture was independent of age, sex distribution, and the duration of exposure to anti-diabetic drugs. When developing individualized treatment strategies, the clinical efficacy of anti-diabetic drugs must be weighed against their benefits and risks brought about by individual differences of patients.

Systematic review registration: This Systematic Review was prospectively registered on the PROSPERO (https://www.crd.york.ac.uk/PROSPERO/, registration number CRD42020189464).

Keywords: anti-diabetic drug; fracture; meta-analysis; systematic review; type 2 diabetes mellitus.

Mutations in ABCC8 have been identified in pulmonary arterial hypertension (PAH). ABCC8 encodes SUR1, a regulatory subunit of the ATP-sensitive-potassium channel Kir6.2. However, the pathophysiological role of the SUR1/Kir6.2 channel in PAH is unknown. We hypothesized that activation of SUR1 could be a novel potential target for PAH. We analysed the expression of SUR1/Kir6.2 in the lungs and pulmonary artery (PA) in human PAH or experimental pulmonary hypertension (PH). The contribution of SUR1 in human or rat PA tone was evaluated, and we measured the consequences of in vivo activation of SUR1 in control and PH rats. SUR1 and Kir6.2 protein expression was not reduced in the lungs or human pulmonary arterial endothelial cells and smooth muscle cells (hPAECs and hPASMCs) from PAH or experimentally induced PH. We showed that pharmacological activation of SUR1 by 3 different SUR1 activators (diazoxide, VU0071063, and NN414) leads to PA relaxation. Conversely, the inhibition of SUR1/Kir6.2 channels causes PA constriction. In vivo, long- and short-term activation of SUR1 with diazoxide reversed monocrotaline-induced PH in rats. Additionally, in vivo diazoxide application (short protocol) reduced the severity of PH in chronic-hypoxia rats. Moreover, 3 weeks of diazoxide exposure in control rats had no cardiovascular effects. Finally, in vivo, activation of SUR1 with NN414 reduced monocrotaline-induced PH in rats. In PAH and experimental PH, the expression of SUR1/Kir6.2 was still presented. In vivo pharmacological SUR1 activation by two different molecules alleviated experimental PH, providing proof-of-concept that SUR1 activation should be considered for PAH and evaluated more thoroughly.

Keywords: SUR1, ABCC8, pulmonary arterial tone, diazoxide, nateglinide.

This research aims to develop and validate a bioanalytical method for simultaneous estimation of an antidiabetic combination using LC-MS/MS in rat plasma. Nateglinide and metformin hydrochloride are commonly used combination for clinical management of Type 2 diabetes. Hence, simultaneous determination in plasma is essential for the rapid analysis of samples from the pharmacokinetic studies. Statistical optimization was carried out for liquid chromatography (LC) parameters and mass spectroscopic (MS) parameters by design of experiment (DoE) (Design Expert Version 11, Stat Ease Inc., USA) approach. A 3³ full factorial design was used for optimization of LC parameters; %methanol, %formic acid, and flow rate were selected as independent variables, whereas peak area and tailing factor were considered as dependent variables for both drugs. Box-Behnken design was used to optimize MS parameters including drying gas flow rate, nebulizing gas flow rate, DL temperature, heat block temperature, and positive voltage as independent factors, and responses selected were [M + H]⁺ intensity of nateglinide and metformin hydrochloride. The [M + H]⁺ intensity of the optimized method for nateglinide and metformin hydrochloride were 2,462,838 and 11,873,826, respectively. The model was found significant for optimizing LC and MS parameters with p < 0.05 for both nateglinide and metformin hydrochloride. The optimized method was validated as per the ICH-M10 guideline, which was accurate, precise, and selective. The method was cost-effective and capable of quantitating concentrations in picogram levels for nateglinide and metformin hydrochloride simultaneously.

Keywords: LC-MS/MS; bioanalytical method; metformin hydrochloride; nateglinide; rat plasma.

Sophisticated nanomedicines are continually being developed, but big obstacles remain before they finish the drug release mission. The first challenge is rupture possibility of structure when infinite dilution, competitive reaction of electrolytes and protein in blood circulation. In addition, low responsive drug release efficiency in the lesion site remains the major challenge for clinical application of nanomedicine combination treatment. In this study, we discussed the opportunities for Alzheimer's disease (AD) combination therapy based on the thermodynamically ultra-stable dextran conjugated prodrug micelles. Dextran-nateglinide conjugated prodrug micelles (NA) and dextran-vitamin E succinate conjugated prodrug micelles (VES) presented ultra-low critical micelle concentration of ~10^-5 mM and high physiological stability when challenged by NaCl, sodium dodecyl sulphate (SDS), dodecyl dimethyl benzyl ammonium chloride (DDBAC) and no rupture of structure happened. The NA/insulin polymer-drug conjugate micelles (NA/INS PDC) and VES/insulin polymer-drug conjugate micelles (VES/INS PDC) efficiently cleaved by reactive oxygen species (ROS), leading to over 80% release of the encapsulated and conjugated drugs. The combination of nateglinide and insulin, vitamin E succinate and insulin improved the glucose metabolism, reduced oxidative stress, improved the mitochondrial function and recovered the cognitive capacity of mice. This work demonstrated a paradigm for specific and high efficacy AD combination therapy.

Keywords: Alzheimer's disease; Combination therapy; Ultra-low critical micelle concentration.