Enantioselective determination of ornidazole in human plasma by liquid chromatography–tandem mass spectrometry on a Chiral-AGP column

Evaluation of Ornidazole Tablets Bioequivalence in Chinese Healthy Participants Under Fasted and Fed Conditions Using Pharmacokinetic Parameters

BACKGROUND AND OBJECTIVE

Ornidazole, the third generation of nitroimidazole derivatives after metronidazole and tinidazole, it exerts both bactericidal and antiprotozoal effects. The purpose of this study was to evaluate the pharmacokinetic and bioequivalence of two ornidazole tablets manufactured by two different manufacturers based on their pharmacokinetic parameters.

PATIENTS AND METHODS

Fasted and fed healthy Chinese volunteers participated in a randomized sequence, single-dose, open-label, two-period crossover trial. There were 24 participants in both the fed study and the fasted study. Following a 7-day washout period before receiving the alternative formulation, eligible research participants were randomly assigned (1:1) to receive a single dosage of either the reference formulation or the test formulation. Following tablet administration, plasma samples were obtained over 72 h and analyzed using liquid chromatography tandem mass spectrometry (LC-MS/MS) to evaluate ornidazole contents. maximum plasma concentration (Cmax), time to Cmax (Tmax), the area under the curve (AUC) from t = 0 to infinity (AUC0-∞), AUC from t = 0 to the last quantifiable concentration (AUC0-t), half-life (t1/2), and terminal elimination rate constant (z) were evaluated as pharmacokinetic (PK) parameters. The safety evaluation involved adverse events (AEs) incidence and alterations in laboratory tests (hepatic function, blood biochemistry, hematology, and urinalysis) or vital signs (temperature, pulse, and blood pressure).

RESULTS

For the bioequivalence assessment in the fast trial, the prime PK parameters comparison between the reference and test formulation revealed that the GMR (90% CI) values for AUC0-t, Cmax, and AUC0-∞ were 100.97% (99.12-102.85%), 99.88% (90.63-110.08%), and 101.12% (99.17-103.11%), respectively. For the bioequivalence assessment in the fed trial, the key PK parameters comparison between the reference and test formulations revealed that the GMR (90% CI) values for AUC0-t, Cmax, and AUC0-∞ were 103.00% (100.94-105.11%), 101.90% (99.63-104.22%), and 102.99% (100.87-105.16%), respectively. The geometric mean ratios (GMRs) for the primary pharmacokinetic parameters (Cmax, AUC0-72, and AUC0-∞) between the two formulations and the corresponding 90% confidence intervals (CIs) were all within the range of 80.00-125.00% for both the fasting and fed states. Both treatments have comparable safety profiles.

CONCLUSION

The bioequivalence and tolerability of ornidazole tablet reference and test formulations were evaluated among healthy Chinese participants under both fasting and fed conditions. The results indicated that both formulations were bioequivalent and generally well tolerated; besides, the interaction between food and drug may affect drug pharmacokinetics.

TRIAL REGISTRATION

CTR20212873, registered on 15 November 2021; ChiCTR2300069098, registered on 7 March 2023.

Homochiral Eu3+@MOF Composite for the Enantioselective Detection and Separation of (R/S)-Ornidazole

The development of homochiral materials for the enantioselective detection and separation of chiral drugs is in high demand for the pharmaceutical industry. Herein, an anionic homochiral metal-organic framework (HMOF) with in situ generated [Me₂NH₂]⁺ counterions, {[Me₂NH₂]₂[Zn₂(d-L)₂(HCO₂)(OH)]·5H₂O}_n (HMOF-1), was synthesized using a d-camphorate-derived enantiopure dicarboxylate ligand, 4,4'-[[(1R,3S)-1,2,2-trimethylcyclopentane-1,3-dicarbonyl]bis(azanediyl)]dibenzoic acid (d-H₂L) via a simple solvothermal method. Interestingly, HMOF-1 could be used as a parent framework to encapsulate Eu³⁺ cations via an ion-exchange process, yielding an Eu³⁺@HMOF-1 composite with dual-luminescent centers. The obtained Eu³⁺@HMOF-1 has high chemical stability and good luminescence stability in water. Importantly, Eu³⁺@HMOF-1 exhibits enhanced enantioselectivity and sensitivity in the detection of an important chiral nitroimidazole antibiotic, (R/S)-ornidazole (ONZ) in comparison to HMOF-1 under the same aqueous conditions. The enantiomeric excess (ee) value of the ONZ enantiomers can be accurately determined by the ratio of dual emission from the ligand and Eu³⁺. In addition, Eu³⁺@HMOF-1 shows the enantioselective separation of racemic ONZ enantiomers with an ee value of 86.6%. This work provides a simple strategy for the preparation of Ln^III-incorporated HMOF composite materials for the simultaneous enantioselective detection and separation of chiral drugs.

A novel carbon dot/polyacrylamide composite hydrogel film for reversible detection of the antibacterial drug ornidazole

A carbon dot/polyacrylamide (CDs/PAM) composite hydrogel film with stable fluorescence performance was fabricated by merging a hydrogel film and carbon dots (CDs) with blue fluorescence, which were prepared by hydrothermal synthesis using anhydrous citric acid and acrylamide as carbon sources. The obtained CDs/PAM composite hydrogel film exhibited a good fluorescence quenching effect on ornidazole (ONZ), and can be used for the quantitative detection of ONZ. In the ONZ concentration range of 5-60 μM, a good linear relationship between the fluorescence quenching efficiency of the CDs/PAM composite hydrogel film and the concentration of ONZ solution was obtained with a low detection limit of 2.35 μM. In addition, the detection system has good selectivity and strong anti-interference capacity, and can be used in repeated cycles for detection.

High performance affinity chromatography and related separation methods for the analysis of biological and pharmaceutical agents

The last few decades have witnessed the development of many high-performance separation methods that use biologically related binding agents. The combination of HPLC with these binding agents results in a technique known as high performance affinity chromatography (HPAC). This review will discuss the general principles of HPAC and related techniques, with an emphasis on their use for the analysis of biological compounds and pharmaceutical agents. Various types of binding agents for these methods will be considered, including antibodies, immunoglobulin-binding proteins, aptamers, enzymes, lectins, transport proteins, lipids, and carbohydrates. Formats that will be discussed for these methods range from the direct detection of an analyte to indirect detection based on chromatographic immunoassays, as well as schemes based on analyte extraction or depletion, post-column detection, and multi-column systems. The use of biological agents in HPLC for chiral separations will also be considered, along with the use of HPAC as a tool to screen or study biological interactions. Various examples will be presented to illustrate these approaches and their applications in fields such as biochemistry, clinical chemistry, and pharmaceutical research.

Chromatographic Studies of Protein-Based Chiral Separations

The development of separation methods for the analysis and resolution of chiral drugs and solutes has been an area of ongoing interest in pharmaceutical research. The use of proteins as chiral binding agents in high-performance liquid chromatography (HPLC) has been an approach that has received particular attention in such work. This report provides an overview of proteins that have been used as binding agents to create chiral stationary phases (CSPs) and in the use of chromatographic methods to study these materials and protein-based chiral separations. The supports and methods that have been employed to prepare protein-based CSPs will also be discussed and compared. Specific types of CSPs that are considered include those that employ serum transport proteins (e.g., human serum albumin, bovine serum albumin, and alpha1-acid glycoprotein), enzymes (e.g., penicillin G acylase, cellobiohydrolases, and α-chymotrypsin) or other types of proteins (e.g., ovomucoid, antibodies, and avidin or streptavidin). The properties and applications for each type of protein and CSP will also be discussed in terms of their use in chromatography and chiral separations.

Experimental and theoretical study of ornidazole

The Fourier transform infrared (FT-IR) and the Fourier transform Raman (FT-Raman) spectra of the title molecule in solid phase were recorded in the region 4000-400 cm(-1) and 4000-100 cm(-1) respectively. The geometrical parameters and energies were investigated with the help of Density Functional Theory (DFT) employing B3LYP method and 6-31G (d, p) basis set. The analysis was supported by electrostatic potential maps and calculation of HOMO-LUMO. UV, FT-IR and FT-Raman spectra of ornidazole were calculated and compared with experimental results. Thermodynamic properties like entropy, heat capacity, have been calculated for the molecule. The predicted first hyperpolarizability also shows that the molecule might have a reasonably good non-linear optical (NLO) behavior. The intramolecular contacts have been interpreted using natural bond orbital (NBO) and natural localized molecular orbital (NLMO) analysis.

Simultaneous determination of ornidazole and its main metabolites in human plasma by LC–MS/MS: application to a pharmacokinetic study

Background: Ornidazole is a 5-nitroimidazole antimicrobial agent used for almost 40 years. A novel LC–MS/MS assay was developed and validated for the simultaneous determination of ornidazole and its main metabolites (M3, M6, M16–1, and M16–2) in human plasma. Results: After extraction from 100 μl of plasma by protein precipitation with acetonitrile, all the analytes were separated on a Capcell PAK MG C18 column (100 × 4.6 mm, 5 μm) within 5.0 min and detected by ESI-MS/MS in the positive mode. The validation results met the acceptance criteria as per the US FDA and EMA guidelines. Conclusion: The validated method was successfully applied to a pharmacokinetic study after oral administration of 1000 mg ornidazole to six healthy Chinese volunteers.

Quantification of levornidazole and its metabolites in human plasma and urine by ultra-performance liquid chromatography-mass spectrometry

We developed and validated an ultra-performance liquid chromatographic (UPLC) method coupled with atmospheric pressure chemical ionization (APCI) mass spectrometry for simultaneous determination of levornidazole and its first-pass metabolites, l-chloro-3-(2-hydroxymethyl-5-nitro-l-imidazolyl)-2-propanol (Ml), 2-methyl-5-nitroimidazole (M2) and 3-(2-methyl-5-nitro-1-imidazolyl)-1,2-propanediol (M4), in human plasma and urine. The biological samples were pretreated by protein precipitation and liquid-liquid extraction and analyzed using an ACQUITY UPLC CSH C18 column (2.1×50 mm, 1.7 μm) and a QTRAP mass spectrometer in multiple reaction monitoring mode via APCI. Acetonitrile and 0.1% formic acid in water was used as the mobile phase in gradient elution at a flow rate of 0.6 mL/min. The lower limit of quantification of this method was 0.0100, 0.00500, 0.0200 and 0.00250 μg/mL for levornidazole, M1, M2 and M4, respectively. The linear calibration curves were obtained for levornidazole, M1, M2, and M4 over the range of 0.0100-5.00, 0.00500-2.50, 0.0200-10.0 and 0.00250-1.25 μg/mL, respectively. The intra- and inter-batch precision was less than 12.2% in plasma and less than 10.8% in urine. The intra- and inter-batch accuracy was 87.8-105.7% in plasma and 92.8-109.2% in urine. The mean recovery of levornidazole, M1, M2 and M4 was 91.1-105.1%, 95.8-103.8%, 87.8-96.8%, 96.8-100.6% from plasma and 96.0-100.9%, 96.9-107.9%, 95.1-102.7%, 103.7-105.9% from urine respectively. This method was validated under various conditions, including room temperature, freeze-thaw cycles, long-term storage at -40 ± 5°C, after pretreatment in the autosampler (at 10°C), and 10- and 100-fold dilution. This newly established analytical method was successfully applied in a pharmacokinetic study following single intravenous infusion of levornidazole in 24 healthy Chinese subjects.