A validated UPLC-MS/MS method for determination of tebipenem in human plasma and its application to a pharmacokinetic study in healthy volunteers

A rapid and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for determining tebipenem (TBPM) in human plasma. Plasma samples were prepared following a single-step protein precipitation method using acetonitrile and 3-morpholinopropanesulfonic acid (MOPS, pH 7.0, 50 mM) which equal volume of plasma samples were added for stabilizing the analyte. Separation was achieved using an ACQUITY UPLC BEH C18 (1.7 μm, 2.1 × 50 mm) column. A repeated gradient program was employed for reducing the carryover effect, and the total chromatographic run time was 3.0 min. Method validation results showed TBPM was linear in its analytical range i.e. between 0.1-20 μg/mL (r²>0.99), and the lower limit of quantification (LLOQ) was 0.1 μg/mL. The intra-run and inter-run precision (coefficient of variation, CV) was within 3.81%, and the accuracy (relative error, RE) was within ± 8.56%. The carryover was restricted below 8.1%. Matrix effects were minimal, and recovery of TBPM was 90.19-95.74%. The stability of TBPM in plasma sample stored at room temperature (25 °C) for 4 h, at -20 °C for 3 days, at -80 °C for 30 days, five freeze-thaw cycles at -80 °C and processed samples at auto sampler vials (8 °C) for 24 h were within 91.11-106.33%. Finally, the validated method was successfully applied to a pharmacokinetic study of TBPM in healthy volunteers after oral administration of tebipenem pivoxil (TBPM-PI).

Cyclodextrins as multifunctional excipients: Influence of inclusion into β-cyclodextrin on physicochemical and biological properties of tebipenem pivoxil

A novel approach for drug design based on the oral carbapenem analog tebipenem pivoxil (TP) has been proposed. The formation of the tebipenem pivoxil-β-cyclodextrin (TP-β-CD) complex resulted in changes concerning physicochemical properties of TP, which is significant for planning the development of an innovative pharmaceutical formulation as well as in the modifications of biological activity profile of the studied delivery system. The inclusion of TP into β-cyclodextrin (β-CD) was confirmed by spectral (infrared and Raman spectroscopies) and thermal method (differential scanning calorimetry). Precise indications of TP domains responsible for interaction with β-CD were possible through a theoretical approach. The most important physicochemical modifications obtained as an effect of TP inclusion were changes in solubility and its rate depending on acceptor fluids, and an increase in chemical stability in the solid state. Biologically essential effects of TP and β-CD interactions were decreased TP permeability through Caco-2 cell monolayers with the use of efflux effect inhibition and increased antibacterial activity. The proposed approach is an opportunity for development of the treatment in resistant bacterial infections, in which along with physicochemical modifications induced by a drug carrier impact, a carrier synergy with a pharmacological potential of an active pharmaceutical substance could be used.