A Review of Analytical Techniques for Determination of Glimepiride: Present and Perspectives

The Clinical Pharmacokinetics and Pharmacodynamics of Glimepiride-A Systematic Review and Meta-Analysis

Background/Objectives: Glimepiride (GLM), a commonly used sulphonylurea drug for the management of type 2 diabetes mellitus (T2DM), has been the subject of numerous studies exploring its kinetic behaviors. However, a comprehensive evaluation that synthesizes all available pharmacokinetic (PK) data across diverse populations remains limited. This systematic review aims to provide detailed knowledge about the pharmacokinetics (PK), the associated pharmacodynamics (PD), and the drug interactions of GLM, which can be used to assess key parameters and identify factors influencing variability across diverse populations and clinical settings. Methods: A systematic search of the peer-reviewed literature was combined using major databases-Google Scholar, PubMed, Cochrane, and ScienceDirect, to identify studies reporting the PK of GLM. Following the data extraction, a meta-analysis using a random effect (RE) model was performed, where feasible, to quantitatively assess the variability of key PK parameters across different studies to create a more robust PK parameter estimate. Results: The final screening has yielded 40 articles. The area under the curve (AUC0-∞) and the peak concentration (Cmax) rise proportionately with increasing doses, depicting the linear kinetics of GLM. The subjects with genotype CYP2C9 *1/*3 depicted a 4-fold higher (AUC0-∞) as compared to that of the CYP2C9 *1/*1 population. Preliminary meta-analysis results indicated significant variability in (AUC0-∞) and Cmax values among different studies. Heterogeneity across studies was high, warranting the use of RE models. Conclusions: The findings of this review would be helpful in the development and evaluation of PK models that may aid in suggesting individualized dosing.

Transfer of Proteins from Cultured Human Adipose to Blood Cells and Induction of Anabolic Phenotype Are Controlled by Serum, Insulin and Sulfonylurea Drugs

Glycosylphosphatidylinositol-anchored proteins (GPI-APs) are anchored at the outer leaflet of eukaryotic plasma membranes (PMs) only by carboxy-terminal covalently coupled GPI. GPI-APs are known to be released from the surface of donor cells in response to insulin and antidiabetic sulfonylureas (SUs) by lipolytic cleavage of the GPI or upon metabolic derangement as full-length GPI-APs with the complete GPI attached. Full-length GPI-APs become removed from extracellular compartments by binding to serum proteins, such as GPI-specific phospholipase D (GPLD1), or insertion into the PMs of acceptor cells. Here, the interplay between the lipolytic release and intercellular transfer of GPI-APs and its potential functional impact was studied using transwell co-culture with human adipocytes as insulin-/SU-responsive donor cells and GPI-deficient erythroleukemia as acceptor cells (ELCs). Measurement of the transfer as the expression of full-length GPI-APs at the ELC PMs by their microfluidic chip-based sensing with GPI-binding α-toxin and GPI-APs antibodies and of the ELC anabolic state as glycogen synthesis upon incubation with insulin, SUs and serum yielded the following results: (i) Loss of GPI-APs from the PM upon termination of their transfer and decline of glycogen synthesis in ELCs, as well as prolongation of the PM expression of transferred GPI-APs upon inhibition of their endocytosis and upregulated glycogen synthesis follow similar time courses. (ii) Insulin and SUs inhibit both GPI-AP transfer and glycogen synthesis upregulation in a concentration-dependent fashion, with the efficacies of the SUs increasing with their blood glucose-lowering activity. (iii) Serum from rats eliminates insulin- and SU-inhibition of both GPI-APs' transfer and glycogen synthesis in a volume-dependent fashion, with the potency increasing with their metabolic derangement. (iv) In rat serum, full-length GPI-APs bind to proteins, among them (inhibited) GPLD1, with the efficacy increasing with the metabolic derangement. (v) GPI-APs are displaced from serum proteins by synthetic phosphoinositolglycans and then transferred to ELCs with accompanying stimulation of glycogen synthesis, each with efficacies increasing with their structural similarity to the GPI glycan core. Thus, both insulin and SUs either block or foster transfer when serum proteins are depleted of or loaded with full-length GPI-APs, respectively, i.e., in the normal or metabolically deranged state. The transfer of the anabolic state from somatic to blood cells over long distance and its "indirect" complex control by insulin, SUs and serum proteins support the (patho)physiological relevance of the intercellular transfer of GPI-APs.

Development and validation of RP-HPLC method for glimepiride and its application for a novel self-nanoemulsifying powder (SNEP) formulation analysis and dissolution study

Background

There are many analytical methods available for estimation of glimepiride in biological samples and pharmaceutical preparations. To our knowledge, there is no specific reverse-phase high-performance liquid chromatography (RP-HPLC) method for estimation of glimepiride and its dissolution study in self-nanoemulsifying powder (SNEP) formulation.

Methods

A simple method was carried out on a 5-μm particle octadesyl silane (ODS) column (250 × 4.6 mm) with acetonitrile: 0.2 M phosphate buffer (pH = 7.4) 40:60 v/v as a mobile phase at a flow rate of 1 mL/min, and quantification was achieved at 228 nm using PDA detector.

Results

The correlation coefficient (r 2) was found to be 0.999 over the concentration range of 0.2 to 2 μg/mL for glimepiride. The method was validated for linearity, accuracy, and precision. The limit of detection and limit of quantification were found to be 0.38 and 1.17 μg/mL, respectively.

Conclusions

The proposed method was found to be simple, precise, suitable, and accurate for quantification of glimepiride as an alternative to the existing methods for the routine analysis of glimepiride in pharmaceutical formulations and in vitro dissolution studies.

In vitro assessment of 36 CYP2C9 allelic isoforms found in the Chinese population on the metabolism of glimepiride

Of the 57 reported CYP2C9 alleles, to date, 36 of them have been identified in the Chinese population. The aim of this study was to assess the catalytic characteristics of these allelic isoforms and their effects on the metabolism of glimepiride in vitro. Baculovirus-mediated expressing system was used to highly express wild-type and the 35 CYP2C9 allelic variants in insect cell microsomes. Then, the enzymatic characteristics of each variant were evaluated using glimepiride as the substrate. Reactions were performed at 37°C with the insect microsomes and 0.125-10 μM glimepiride for 40 min. After termination, the products were extracted and used for signal collection by LC-MS/MS. Of the 36 tested CYP2C9 allelic isoforms, only four variants (CYP2C9.40, CYP2C9.47, CYP2C9.51 and CYP2C9.54) exhibited similar relative clearance values to that of wild-type CYP2C9.1. In addition, one variant (CYP2C9.36) showed a higher intrinsic clearance value than the wild-type protein, while the remaining 30 CYP2C9 allelic isoforms exhibited significantly decreased clearance values (from 0.1% to 87.2%) compared to CYP2C9.1. This study provided the most comprehensive data on the enzymatic activities of all reported CYP2C9 variants in the Chinese population with regard to the commonly used antidiabetic drug, glimepiride. Our results indicate that most of the tested rare alleles significantly decrease the catalytic activity of CYP2C9 variants towards glimepiride hydroxylation in vitro.