Pharmacokinetics of pentoxifylline and its 5-hydroxyhexyl metabolite following intravenous administration in cattle

Evaluating the effectiveness of advanced platelet-rich fibrin, photobiomodulation, pentoxifylline, and Alveogyl in the treatment of alveolar osteitis: a randomized controlled clinical trial

BACKGROUND

Alveolar osteitis is a type of small-scale osteomyelitis of the alveolar bone that occurs after tooth extraction, the etiology of which remains unknown, and alternative methods are being investigated for its treatment. The aim of this study was to compare the effectiveness of advanced platelet-rich fibrin (A-PRF), photobiomodulation (PBM), and Alveogyl (butamben, idoform, eugenol), which have shown success in the treatment of alveolar osteitis, with that of pentoxifylline (PTX) to determine whether PTX could be an alternative treatment for alveolar osteitis.

METHODS

This study included 80 healthy volunteers diagnosed with alveolar osteitis in the extraction sockets of their mandibular first, second, and third molars. The patients were divided into four groups, with 20 patients in each group: A-PRF, PBM, PTX, and Alveogyl. After physiological saline irrigation, the patients were treated according to their respective group. The patients were followed up on the 2nd, 4th, 7th, and 14th days. Primary outcomes included pain assessment and the evaluation of soft tissue healing. Pain was assessed via the visual analog scale (VAS), soft tissue healing was evaluated via the Landry Healing Index (LHI), and granulation tissue was measured. Age and sex were used as study variables. The data were analyzed via ANOVA and post hoc tests to compare the treatment groups.

RESULTS

There was no statistically significant difference in the mean VAS score between the groups (p > 0.05). However, the degree of reduction in the VAS score increased in the following order: A-PRF, PBM, PTX, and Alveogyl. In the LHI data, there was a statistically significant difference in the mean scores between the groups, with Alveogyl being favored preoperatively and PBM being favored at the 2nd week (p < 0.05). Statistically significant differences were observed in granulation tissue measurements on the preoperative day, as well as on Days 4 and 7, in favor of Alveogyl on Day 4 and PBM on Day 7 (p < 0.05). The greatest increase in granulation tissue scores was observed in the A-PRF group, whereas the greatest change in LHI scores was observed in the PBM group. PTX did not produce a statistically significant difference in soft tissue healing, although there were periods when it showed results similar to those of Alveogyl and PBM. There were significant differences between the VAS score, granulation tissue score and LHI score in terms of age and sex within the time periods followed.

CONCLUSION

The findings of this study indicate that although PTX has similar efficacy in terms of wound healing and analgesic properties to the methods used, it does not offer significant advantages. Compared with other methods, A-PRF and PBM have provided better results in the treatment of alveolar osteitis, particularly regarding pain and soft tissue healing.

TRIAL REGISTRATION

The study was retrospectively registered in the clinical trial registry with the number TCTR20231014003 on 14.10.2023.

Development and Validation a UPLC-MS/MS Method for Quantification of Pentoxifylline in Beagle Plasma: Application for Pharmacokinetic Study of Food Effect

Purpose

To develop an UPLC-MS/MS method for the quantitative analysis of pentoxifylline in beagle dog plasma and apply it to a pharmacokinetic study of food effect.

Methods

Sample separation was achieved using a Kinetex Phenyl-Hexyl column (50 × 2.1 mm, 1.7 μm) with a gradient elution program in 5.5 min after a simple protein precipitation with methanol. Using the mobile phase that made up by 0.2% formic acid and 5mM ammonium formate water (A) and methanol (B). Quantitation was carried out using the positive ionization mode with multiple reaction monitoring (MRM). A randomized, single-dose, two-period crossover study was conducted in six fasted or fed beagles that received 400 mg pentoxifylline sustained-release tablets (Brand name: Shuanling™, CSPC Pharmaceutical Group). WinNonlin® software was used to calculate pharmacokinetic parameters.

Results

The linear calibration range was 2-1000 ng/mL (r2> 0.99). Both intra- and inter-batch precision were less than 6.27%, and the accuracy ranged from 88.65% to 97.18%. Pentoxifylline was readily absorbed in fasted and fed dogs administered a dose of 400 mg (tmax:1.54h vs 1.83h). Compared to the fasted group, the AUC0→t and Cmax in the fed group increased by 1.71-fold and 1.30-fold, respectively. In the fasted group, the AUC0→t and Cmax values were 4684.08 h•ng/mL and 2402.33 ng/mL, respectively. In the fed group, these values were 8027.75 h•ng/mL and 3119.67 ng/mL. The difference in AUC0-t between the fed and fasted group was statistically significant.

Conclusion

The novel optimized UPLC-MS/MS assay is an effective tool for the determination of pentoxifylline and has been successfully applied in pharmacokinetic studies of pentoxifylline in beagle dogs. The administration of pentoxifylline sustained-release tablets with food significantly increased the area under the time curve, and it is recommended that they should be administered during or shortly after feeding.

The Molecular Mechanism Regulating Diurnal Rhythm of Flavin-Containing Monooxygenase 5 in Mouse Liver

Flavin-containing monooxygenase 5 (FMO5) is a phase I enzyme that plays an important role in xenobiotic metabolism. Here, we aimed to characterize diurnal rhythms of Fmo5 expression and activity in mouse liver and to investigate the potential roles of clock genes (Bmal1, Rev-erbα, and E4bp4) in the generation of diurnal rhythms. Fmo5 mRNA and protein showed robust diurnal rhythms, with peak values at zeitgeber time (ZT) 10/14 and trough values at ZT2/22 in mouse liver. Consistently, a diurnal rhythm was observed for in vitro microsomal Baeyer-Villiger oxidation of pentoxifylline (PTX), a specific reaction catalyzed by Fmo5. Pharmacokinetic studies revealed a more extensive Baeyer-Villiger oxidation of PTX at dosing time of ZT14 than at ZT2, consistent with the diurnal pattern of Fmo5 protein. Fmo5 expression was downregulated and its rhythm was blunted in Bmal1 -/- and Rev-erbα -/- mice. Positive regulation of Fmo5 by Bmal1 and Rev-erbα was confirmed in primary mouse hepatocytes and/or Hepa1-6 cells. Furthermore, Fmo5 expression was upregulated and its rhythm was attenuated in E4bp4 -/- mice. Negative regulation of Fmo5 by E4bp4 was validated using primary mouse hepatocytes. Combined luciferase reporter and chromatin immunoprecipitation assays demonstrated that Bmal1 (a known Rev-erbα activator) activated Fmo5 transcription via direct binding to an E-box (-1822/-1816 bp) in the promoter, whereas E4bp4 (a known Rev-erbα target gene) inhibited Fmo5 transcription by binding to two D-boxes (-1726/-1718 and -804/-796 bp). In conclusion, circadian clock genes control diurnal expression of Fmo5 through transcriptional actions on E-box and D-box cis-elements. SIGNIFICANCE STATEMENT: Hepatic Fmo5 displayed diurnal rhythmicities in expression and activity in mice. We uncovered the molecular mechanism by which the rhythmic Fmo5 expression was generated. Fmo5 promoter presents E-box and D-box binding elements for transcriptional actions from circadian clock proteins such as Bmal1, E4bp4, and Dbp. These findings have implications for understanding clock-controlled drug metabolism and for facilitating the practice of chronotherapeutics.