Validation of the ADVIA Centaur® XP system for the determination of insulin and its application

Bioequivalence Study of Miglitol Orally Disintegrating Tablets in Healthy Chinese Volunteers Under Fasting Condition Based on Pharmacodynamic and Pharmacokinetic Parameters

To investigate the bioequivalence of miglitol orally disintegrating tablets in healthy Chinese volunteers based on pharmacodynamic (PD) and pharmacokinetic (PK) parameters. Additionally, the safety profile was estimated. Two randomized, open-label, single-dose, crossover trials were conducted under fasting conditions. In the PD trial (CTR20191811), 45 healthy volunteers were randomly divided into 3 groups in a 1:1:1 ratio and administered sucrose alone or coadministered with 50 mg of miglitol orally disintegrating tablet test or reference formulation/sucrose. In the PK trial (CTR20191696), 24 healthy volunteers were randomized (1:1) to receive the test or reference formulation (50 mg). Blood samples were collected at 15 and 17 sampling points per cycle in the PD and PK trials, respectively. Plasma miglitol and serum glucose concentrations were analyzed using a validated liquid chromatography-tandem mass spectrometry method. Serum insulin concentrations were measured using electrochemiluminescent immunoassay. Statistical analyses for the PD and PK parameters were subsequently performed. The volunteers' physical indicators were monitored and documented during the entire study to estimate drug safety. The PD and PK parameters of the two formulations were similar. The main PD and PK end points were both within the prespecified range of 80%-125%. The incidences of treatment-emergent adverse events (TEAEs) and drug-related TEAEs were similar between the test and reference formulation groups, and no serious TEAEs or deaths occurred during the 2 trials. These 2 formulations were demonstrated to be bioequivalent and well tolerated in healthy Chinese volunteers under fasting condition.

Measurement comparability of insulin assays using conventional immunoassay kits

BACKGROUND

The standardization of measurement aims to achieve comparability of results regardless of the analytical methods and the laboratory where analyses are carried out. In this paper, a comparison of results from several immunoassay-based insulin analysis kits is described, and the steps necessary to improve comparability are discussed.

METHODS

Four manual enzyme-linked immunosorbent assay (ELISA) kits produced by Mercodia, Alpco, Epitope Diagnostics, and Abcam, and three automated chemiluminescent (CLIA) insulin assay kits (Siemens Centaur XP, Unicel Dxl800, Cobas e801) were compared by analyzing human serum samples and certified reference materials for human insulin.

RESULTS

The seven evaluated assay kits showed substantial discrepancies in the results, with relative standard deviation ranges between 1.7% and 23.2%. We find that the traceability chains and the unit conversion factors are not yet harmonized, and current reference materials for insulin are not applicable for immunoassay-based method validation due to the use of different matrices.

CONCLUSIONS

The findings suggest the need to fine tune insulin analysis methods, measurement traceability, and any conversion factor used in post-analysis steps in accordance with the necessity for standardization.

An ultrasensitive electrochemical aptasensor based on a single-stranded aptamer-Au@Fe-MIL-88 complex using methylene blue as an electrochemical probe for insulin detection

This work introduces an electrochemical aptasensor based on a single-stranded aptamer-Au@Fe-MIL-88 complex for sensitive and selective determination of insulin using differential pulls voltammetry. Au@Fe-MIL-88 with a large surface area was synthesized and employed as a suitable substrate for immobilization of the aptamer (APT-Au@Fe-MIL-88). Methylene blue (MB), as an electrochemical probe, was intercalated into the aptamer. Graphene oxide (GO) and zinc sulfide (ZnS) were placed on the Au electrode to amplify the MB current. Also, ZnS improves the immobilization of APT-Au@Fe-MIL-88 into the aptasensor through the strong interaction of Au-S. In the presence of the insulin, MB is released from the aptamer due to DNA conformational change, and as a result, the peak intensity of the intercalated MB was decreased. Under optimal conditions, the change in the current of MB was proportional to the insulin concentration in the range of 5.0 × 10^-16-5.0 × 10^-11 mol L^-1, with a superior ultra-low detection limit of 1.3 × 10^-16 mol L^-1. It was observed that the aptasensor is suitable for determining insulin in serum samples with good sensitivity and reproducibility and with recoveries ranging from 96.4 to 102.0%. The relative standard deviations (RSD) were lower than 3.8% (n = 3).

Bioequivalence and Evaluation Parameters Based on the Pharmacodynamics of Miglitol in Healthy Volunteers

The aim of this study was to explore the bioequivalence of miglitol based on pharmacodynamic properties. The study was performed as a single-dose, randomized, open-label, 3-period, 3-way crossover trial over a 7-day washout period. Forty-eight subjects were randomly assigned into 3 groups: (1) miglitol test formulation/sucrose coadministration, (2) miglitol reference formulation/sucrose coadministration, and (3) sucrose administration alone. Serum glucose concentrations were measured by the hexokinase detection method. The peak serum glucose concentration (C_max ) and the area under the serum glucose concentration-time curve through 4 hours (AUC_0-4h ) were used as the main pharmacodynamic parameters to evaluate bioequivalence. The 90% confidence intervals for the geometric mean ratios of C_max and AUC_0-4h were 94.81%-101.07% and 98.82%-100.72%, respectively, which were all within the bioequivalence range of 80.00%-125.00%. The test and reference formulations of miglitol were pharmacodynamically bioequivalent during the trial.