Population pharmacokinetics of gliclazide in normal and diabetic rabbits

Computational studies for pre-evaluation of pharmacological profile of gut microbiota-produced gliclazide metabolites

Background

Gliclazide, a second-generation sulfonylurea derivative still widely used as a second-line treatment for type 2 diabetes mellitus, is well known to be subject to interindividual differences in bioavailability, leading to variations in therapeutic responses among patients. Distinct gut microbiota profiles among individuals are one of the most crucial yet commonly overlooked factors contributing to the variable bioavailability of numerous drugs. In light of the shift towards a more patient-centered approach in diabetes treatment, this study aimed to conduct a pharmacoinformatic analysis of gliclazide metabolites produced by gut microbiota and assess their docking potential with the SUR1 receptor to identify compounds with improved pharmacological profiles compared to the parent drug.

Methods

Ten potential gliclazide metabolites produced by the gut microbiota were screened for their pharmacological properties. Molecular docking analysis regarding SUR1 receptor was performed using Molegro Virtual Docker software. Drug-likeness properties were evaluated using DruLiTo software. Subsequently, the physicochemical and pharmacokinetic properties of gliclazide and its metabolites were determined by using VolSurf+ software package.

Results

All studied metabolites exhibited better intrinsic solubility than gliclazide, which is of interest, considering that solubility is a limiting factor for its bioavailability. Based on the values of investigated molecular descriptors, hydroxylated metabolites M1-M6 showed the most pronounced polar and hydrophilic properties, which could significantly contribute to their in vivo solubility. Additionally, docking analysis revealed that four hydroxyl-metabolites (M1, M3, M4, and M5), although having a slightly poorer permeability through the Caco-2 cells compared to gliclazide, showed the highest binding affinity to the SUR1 receptor and exhibited the most suitable pharmacological properties.

Conclusion

In silico study revealed that hydroxylated gut microbiota-produced gliclazide metabolites should be further investigated as potential drug candidates with improved characteristics compared to parent drug. Moreover, their part in the therapeutic effects of gliclazide should be additionally studied in vivo, in order to elucidate the role of gut microbiota in gliclazide pharmacology, namely from the perspective of personalized medicine.

Formulation, Pharmacokinetics evaluation, and IVIVC Assessment of Gliclazide Multiparticulates in Rat Model

In vitro and in vivo studies of gliclazide (GLZ)-loaded freeze-dried alginate-gelatin (AL-GL) beads were carried out, aiming to modify its oral bioavailability. Crosslinked freeze-dried GLZ AL-GL beads (particle size: 1.5- and 3.0-mm) were prepared. In vitro evaluation of GLZ AL-GL beads included SEM, DSC, FT-IR, and release rate study in gradient media. In vivo study was single-dose (4 mg/kg), randomized, parallel-group design, two-treatment (T: test GLZ AL-GL beads and R: reference product Diamicron® 30-mg MR tablet) conducted in 96 healthy rats. Each group was subdivided into 2 sub-groups (G1 and G2) having different blood sampling schemes for up to 72 h. Assessment of level A in-vitro-in-vivo correlation (IVIVC) model was carried out. AL-GL beads successfully increased GLZ release rate compared to R. GLZ percent released (Q_4h) was 109.34, 86.85, and 43.43% for 1.5-mm and 3.0-mm beads and R, respectively. DSC analysis confirmed the interaction of AL-GL via crosslinking. No chemical interaction of GLZ has occurred as proved by FT-IR. Relative bioavailability (T/R) for AUC_0-∞ was 132.45% for G1 and 146.16% for G2. No significant differences between T and R in the primary pharmacokinetic parameters were determined. T_max values were found to be earlier in the case of G1 than those of G2. A secondary absorption peak of GLZ was clearly detected in the case of R while its sharpness was minimized in T. High IVIVC was established, and hence, the proposed in vitro release model perfectly correlated with the in vivo study. The current study design might be a platform to enable panoramic view for GLZ variability in vivo.

Computational Approaches in Preclinical Studies on Drug Discovery and Development

Because undesirable pharmacokinetics and toxicity are significant reasons for the failure of drug development in the costly late stage, it has been widely recognized that drug ADMET properties should be considered as early as possible to reduce failure rates in the clinical phase of drug discovery. Concurrently, drug recalls have become increasingly common in recent years, prompting pharmaceutical companies to increase attention toward the safety evaluation of preclinical drugs. In vitro and in vivo drug evaluation techniques are currently more mature in preclinical applications, but these technologies are costly. In recent years, with the rapid development of computer science, in silico technology has been widely used to evaluate the relevant properties of drugs in the preclinical stage and has produced many software programs and in silico models, further promoting the study of ADMET in vitro. In this review, we first introduce the two ADMET prediction categories (molecular modeling and data modeling). Then, we perform a systematic classification and description of the databases and software commonly used for ADMET prediction. We focus on some widely studied ADMT properties as well as PBPK simulation, and we list some applications that are related to the prediction categories and web tools. Finally, we discuss challenges and limitations in the preclinical area and propose some suggestions and prospects for the future.

Lipid-Based Gliclazide Nanoparticles for Treatment of Diabetes: Formulation, Pharmacokinetics, Pharmacodynamics and Subacute Toxicity Study

Introduction

Solid lipid nanoparticles (SLNs) are considered a promising system in enhancing the oral bioavailability of poorly water-soluble drugs; owing to their intrinsic ability to increase the solubility together with protecting the incorporated drugs from extensive metabolism.

Objective

Exploiting such properties, SLNs loaded with gliclazide (GLZ) were developed in an attempt to improve the oral bioavailability and the anti-diabetic action of GLZ, together with prolonging its duration of action for better glycemic control.

Methods

SLNs were prepared by ultra-sonication technique using glyceryl behenate (Compritol^®888 ATO) as a lipid matrix and poloxamer 188 (PLX) as a stabilizer. A 2*3 asymmetrical factorial design was adopted to study the effect of different stabilizer concentrations at different sonication times on the shape, and size of the particles, PDI and drug loading. The selected optimum formulation was then freeze dried using trehalose di-hydrate as a cryo-protectant in different ratios with respect to glyceryl behenate concentration. After freeze drying, the formulation was tested for in-vitro drug release, pharmacokinetics, and pharmacodynamics. Safety of the selected formula was established after carrying out a subacute toxicity study.

Results

The factorial design experiment resulted in an optimum formulation coded 10F2 (150 mg PLX/10 min sonication). Scanning electron micrographs showed spherical particles with smooth surface, whereas a ratio of 2:1 cryo-protectant:lipid was found to be optimum with particle size of 245.9 ± 26.2 nm, polydispersity index of 0.482 ± 0.026, and biphasic in-vitro release with an initial burst effect, followed by a prolonged release phase. On the other hand, the selected SLNs exhibited prolonged drug release when compared with the GLZ commercial immediate release (IR) tablets (Diamicron^®). Pharmacokinetics study showed about 5-fold increase in GLZ oral bioavailability loaded in SLNs when compared with raw GLZ powder. Pharmacodynamics study on a diabetic rat model confirmed the better anti-diabetic action of GLZ loaded SLNs when compared to raw GLZ powder. Subacute toxicity study indicated the safety of SLNs upon repetitive oral administration.

Comparative pharmacokinetic evaluation of extended release itopride HCl pellets with once daily tablet formulation in healthy human subjects: a two treatment, four period crossover study in fasted and fed condition

OBJECTIVE

In this study, pharmacokinetics (PKs) and bioavailability of newly developed extended release (ER) Itopride HCl 150 mg encapsulated ER pellets (test) and 150 mg Ganaton ER once-daily (OD) tablets (reference) were compared and evaluated under fasted and fed conditions.

METHODS

Twelve healthy human subjects were enrolled in a single dose, randomized; two treatments, two sequences, four period crossover study. A modified and validated liquid chromatographic method was used for the estimation of Itopride HCl in plasma samples. The data were analyzed through non-compartmental model using PK software Phoenix Winnonlin version 7. The outcome was measured on logarithmically transformed data, where p > 0.05 was considered as non-significant with 90% CI limit of 0.8-1.25.

RESULTS

The C_max, AUC_0-t, and AUC_0-∞ values of Itopride HCl 150 mg ER pellets versus that of OD 150 mg tablets, in fed and fasted states, were within the limits specified by FDA to establish bioequivalence. The relative bioavailability of Itopride HCl 150 mg ER pellets were 1.019 (fed) and 1.081(fasted). The 90% CIs of AUC values for Itopride HCl 150 mg ER pellets and OD 150 mg tablets in fed versus fast were significantly greater and were not within 80-125% limit.

CONCLUSION

The test and reference formulations had similar pharmacokinetic parameters in each condition studied. However, an increase in the amount of drug was observed in the fed state.