Development and validation of sensitive LC/MS/MS method for quantitative bioanalysis of levonorgestrel in rat plasma and application to pharmacokinetics study

Pharmacokinetics of Levonorgestrel in Rat and Minipig and Pharmacokinetics of Etonogestrel in Rat Following Various Administration Routes

1. The objective of these studies was to determine the pharmacokinetics of levonorgestrel and etonogestrel in Sprague-Dawley rat or Göttingen minipig following various administration routes.2. Four sequential crossover studies were conducted: Study 1 administered levonorgestrel 30 µg intravenously and intradermally in four minipigs; Study 2 administered levonorgestrel 30 µg intravenously in 12 rats; Study 3 administered levonorgestrel 60 µg intravenously and subcutaneously in 12 rats; and Study 4 administered etonogestrel 30 µg intravenously in 12 rats. Samples were quantified using liquid chromatography-tandem mass spectrometry and pharmacokinetic parameters were estimated via noncompartmental analysis.3. C_max and AUC_inf for etonogestrel and levonorgestrel were similar following 30 µg intravenous bolus in rat, suggesting comparable pharmacokinetics. Levonorgestrel exposure was dose-proportional in rats, based on two-fold higher AUC_inf following levonorgestrel 60 versus 30 µg. Bioavailability of intradermal and subcutaneous levonorgestrel was 97.7% (Study 1) and 90.3% (Study 3), respectively. The minipig levonorgestrel clearance was 21.5 L/hr, which was about 10-fold higher than both the rat levonorgestrel (range: 0.985 to 1.45 L/hr) and etonogestrel clearance (range: 0.803 to 0.968 L/hr).4. These studies contribute to the gap in knowledge of nonclinical levonorgestrel and etonogestrel pharmacokinetics, which is necessary for ongoing development of long-acting reversible contraceptives.

Assessing the Fungal Simultaneous Removal Efficiency of Carbamazepine, Diclofenac and Ibuprofen in Aquatic Environment

Unused pharmaceutical compounds (PhCs) discharged into the aquatic environment have been regarded as emerging pollutants due to potential harmful effects on humans and the environment. Microbial bioremediation is considered as a viable option for their removal from wastewater. The aim of this study was to assess the simultaneous removal of carbamazepine (CBZ), diclofenac (DCF) and ibuprofen (IBP) by previously isolated fungi (Aspergillus niger, Mucor circinelloides, Trichoderma longibrachiatum, Trametes polyzona, and Rhizopus microsporus). The tolerance to PhCs was conducted by tracking the fungal mycelium mat diameters in solid media and its dry biomass in liquid media, at the drug concentration range of 0.1 to 15 mg/L. The fungal enzymatic activities were determined for lignin peroxidase (LiP), manganese peroxidase (MnP) and laccase (Lac), respectively. The PhC removal efficiency of the fungi was assessed in aerated batch flasks and the drug concentrations and intermediate compounds formation were determined by using SPE-UPLC/MS. A tolerance over 70% was recorded for all the fungi at drug concentration of 0.1 mg/L. Manganese peroxidase was produced by all the fungi with very low amount of LiP, while all the enzymes were produced by T. polyzona. The pH of 4.3, temperature 37 ± 1.5°C and incubation time of 6 days were the optimum parameters for the fungal enzymatic activities. The best removal of CBZ (87%) was achieved by R. microsporus after 10 days. Between 78 and 100% removal of DCF was observed by all the fungi after 24 h, while 98% of IBP was removed after 2 days by M. circinelloides. Only a few intermediate compounds were identified after 3 days and disappeared after 10 days of incubation. This study demonstrated that apart from the basidiomycetes, the ascomycetes and zygomycetes are also producers of ligninolytic enzymes and have the ability to biodegrade emerging pollutants such as PhCs.

Pharmacokinetic and metabolic analysis of an Alzheimer's disease therapeutic in rat serum via microfluidic CZE-MS

Sensitive, high-throughput methods for pharmacokinetic (PK) profiling are essential for potential therapeutics during critical stages of clinical trials. The application of a microfluidic capillary zone electrophoresis mass spectrometry (CZE-MS) method for PK profiling allows for rapid, sensitive and in-depth analysis of multiple samples within a short timeframe. Here, a CZE-MS approach for PK analysis was compared with a traditional UHPLC-MS approach when analyzing serum extracts from rats treated with a potential Alzheimer's disease therapeutic, BNC-1. Resulting PK data generated from both methods displayed statistical similarities. Additionally, the separation efficiency attributed to the use of the CZE-MS method provided substantial metabolic regulation data that was not apparent in the UHPLC-MS method. Additionally, the coupling of the CZE-MS method to the data processing software, MZmine2, was used to monitor changes in metabolism and observe putative BNC-1-derived metabolites. The ability to perform fast analyses without sacrificing sensitivity or metabolic information suggests that this CZE-MS method is ideal for metabolomics-inclusive, high-throughput PK profiling.

LC-MS/MS quantification of progesterone in ovariectomized miniature swine and its application for preliminary pharmacokinetic study of a novel vaginal sustained release system

OBJECTIVE

We here established a simple, fast, robust and sensitive LC-MS/MS method and validated as well for the quantitative analysis of progesterone (PGT) in ovariectomized (OVX) miniature swine plasma. The method was successfully applied to characterize the pharmacokinetics of a progesterone vaginal drug delivery system.

METHODS

Megestrol acetate was utilized as an internal standard (IS). The separation and detection of PGT from endogenous interference was performed successfully by liquid chromatography with gradient elution and mass spectrometry equipped with positive ESI source using MRM mode. The EVA intravaginal rings (IVRs) were manufactured by hot-melt extrusion (HME), afterward were administrated vaginally to OVX minipigs to evaluate PK study.

RESULTS

The calibration curve for swine plasma samples across the concentration ranged between 0.25 ng/mL and 100 ng/mL. The intra- and inter-assay accuracy and precision were lower than ±5% and 5.88%, respectively. Recoveries of PGT and IS were ranging from 114-119% and 96.5-112%, respectively. In vitro study showed that the EVA IVRs release 18 mg/day of PGT continuously over 7 days, and corresponding mean PGT plasma concentration in OVX minipigs (C_AVG) was 4.892 ng/mL.

CONCLUSION

All the study produced reliable results for the measurement of PGT concentration in miniature swine plasma and the method was successfully applied to a PK study for PGT vaginal ring in miniature pigs, which may lay the foundation for further research on the progesterone preparations intended for in assisted reproductive technology.

Data on UPLC/MS method validation for the biodegradation of pharmaceuticals and intermediates by a fungal consortium and on T47DK-Bluc reporter gene assay to assess the reduction of their estrogenic activity

In term of pharmaceutical and their intermediate compounds analysis, UPLC/MS method is a valuable equipment to achieve better confirmation on their biodegradation by fungi. The T47D-KBluc reporter gene assay is an appropriate tool to investigate to removal of estrogenic and antiestrogenic activities of pharmaceuticals and their metabolites from a synthetic wastewater. A consortium of isolated South African indigenous fungi Aspergillus niger, Mucor circinelloides, Trichoderma longibrachiatum, Trametes polyzona and Rhizopus microspores was found to perform a removal of pharmaceuticals and their metabolites and to reduce their estrogenic activity below the limit of detection in a sequencing batch reactor. Here are presented data regarding the phenolic compounds list and the method validation for UPLC/MS analysis used for selected pharmaceutical compounds namely carbamazepine, diclofenac, ibuprofen and their metabolites, as well as the T47D-KBluc bioassay using as positive control, the agonist E₂ for estrogenic activity and the antagonist ICI 182,780 for antiestrogenic activity. For better understanding of the data presented in this paper, please see the research paper “Removal of pharmaceutical’ estrogenic activity of sequencing batch reactor effluents assessed in the T47DK-Bluc reporter gene assay” [1].

Injectable In Situ Forming Depot Systems for Long-Acting Contraception

Up to date, no long-acting reversible contraceptive (LARC) is developed to be injectable through needles smaller than 18 G and can also provide contraception for more than 3 months after single injection. In this study, injectable polymeric in situ forming depot (ISD) systems are developed to have injectability through 21-23 G needles, and capability of sustained release of levonorgestrel (LNG) for at least 7 months in vitro and in vivo after single subcutaneous injection in rats. The systems are polymeric solutions composed of biodegradable poly(lactide-co-glycolide) and poly(lactic acid) polymers dissolved in a mixture of solvents like N-methyl-2-pyrrolidone and benzyl benzoate or triethyl citrate. LNG released from ISD systems successfully suppressed the estrous cycle of rats at plasma concentration above 0.35 ng mL^-1 . At the end of the treatment, when LNG plasma concentration drops down to be nondetectable, predictable return of fertility is observed in rats. The designed ISD systems have great potential to be further developed into robust injectable LARCs that can be injected through a 21 G or smaller needle and achieve a variety of contraception durations with high patient compliance and low cost.

Comparison of ESI- and APCI-LC-MS/MS methods: A case study of levonorgestrel in human plasma

Electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) techniques for liquid chromatography-tandem mass spectrometry (LC-MS/MS) determination of levonorgestrel were evaluated. In consideration of difference in ionization mechanism, the two ionization sources were compared in terms of LC conditions, MS parameters and performance of method. The sensitivity for detection of levonorgestrel with ESI was 0.25 ng/mL which was lower than 1 ng/mL with APCI. Matrix effects were evaluated for levonorgestrel and canrenone (internal standard, IS) in human plasma, and the results showed that APCI source appeared to be slightly less liable to matrix effect than ESI source. With an overall consideration, ESI was chosen as a better ionization technique for rapid and sensitive quantification of levonorgestrel. The optimized LC-ESI-MS/MS method was validated for a linear range of 0.25-50 ng/mL with a correlation coefficient ≥0.99. The intra- and inter-batch precision and accuracy were within 11.72% and 6.58%, respectively. The application of this method was demonstrated by a bioequivalence study following a single oral administration of 1.5 mg levonorgestrel tablets in 21 Chinese healthy female volunteers.

Quantitative determination of gracillin by HPLC-MS/MS after oral administration and its application to a pharmacokinetic study

A sensitive and credible high performance liquid chromatography hyphenated to mass spectrometry (HPLC-MS/MS) was established to quantify the concentration of gracillin in rat plasma. The plasma samples were subjected to a direct protein precipitation process with acetonitrile as a precipitant in a single-step. Ginsenoside Rb1 was selected as an internal standard (IS). The chromatographic separation of analyte and IS were carried out on an Inersil ODS-3 C18 column (250×4.6mm, 5μm) with a binary solvent system containing acetonitrile and 0.1% formic acid in water at a flow rate of 1mLmin(-1) under a gradient elution mode. Mass spectrometric detection was performed on a triple quadrupole tandem mass spectrometer by the multiple reaction monitoring (MRM) mode to examine the precursor-to-daughter ion transitions of 1110.3→948.2 for IS and 886.1→739.9 for gracillin, respectively, in a positive electrospray ionization mode. The calibration curve showed a promising linearity over a concentration range of 0.065-800ngmL(-1) with a better regression coefficient of r(2)=0.9960. The intra- and inter-day precisions (as relative standard deviation) of the assay at three quality control levels were all less than 3.48%, while the intra- and inter-day accuracies (as relative error) ranged from -8.43% to 9.74%, whose data were within the acceptable limits. The mean extraction recoveries of analyte from rat plasma were all more than 74.11%, and no notable matrix effect was observed. Stability experiments revealed that gracillin remained stable throughout the analytical procedure under various stored conditions. The above validated method was successfully used to investigate the pharmacokinetic behaviors of gracillin orally administrated to rats at three proportion doses. The pharmacokinetic analysis would pave the way for understanding the pharmacological actions and provide a meaningful foundation for further development and application in preclinical and clinical use of gracillin in the near future.