L. D’Souza, R. Patel, H. Varga, and C. Morley
Correspondence: The StemX Research Group, SXR Laboratories
Full Article
This ex vivo pharmacology study examined the anti-inflammatory effects of a novel ibuprofen derivative (IBU-107) using peripheral blood mononuclear cells (PBMCs) isolated from healthy UK donors. Cells were stimulated with lipopolysaccharide (LPS) and treated with varying concentrations of IBU-107 or reference ibuprofen. Cytokine release was quantified by ELISA, and cyclooxygenase (COX) activity assessed by enzyme assay. IBU-107 demonstrated dose-dependent inhibition of IL-6 and TNF-α comparable to ibuprofen, with modestly greater suppression of COX-2 activity at higher concentrations (p=0.04). The study complied with UK Human Tissue Authority (HTA) and Health Research Authority (HRA) governance for human sample use. These data suggest that IBU-107 retains core anti-inflammatory properties of ibuprofen with potential for enhanced COX-2 selectivity.
Introduction Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen are widely used for pain and fever management, acting primarily through inhibition of cyclooxygenase (COX) enzymes. Novel ibuprofen derivatives are being developed to optimise COX-1/COX-2 selectivity and reduce gastrointestinal side effects.
IBU-107 is a proprietary ibuprofen analogue with structural modification at the carboxyl group designed to improve COX-2 affinity while maintaining systemic tolerability. This study aimed to characterise its ex vivo pharmacological activity in human PBMCs obtained from healthy donors, as an early step preceding formal preclinical evaluation.
Methods Sample collection: Peripheral blood samples (20 mL) were obtained from six healthy adult volunteers following informed consent. Samples were anonymised and processed within two hours of collection.
Cell isolation and treatment: PBMCs were isolated by Ficoll density centrifugation and cultured in RPMI-1640 supplemented with 10% FBS. Cells were stimulated with 100 ng/mL LPS and treated for 6 hours with vehicle control (0.1% DMSO), Ibuprofen (10 μM), and IBU-107 at 1 μM, 10 μM, and 50 μM.
Assays: Supernatants were analysed for IL-6 and TNF-α using commercial ELISA kits. COX activity was measured via colorimetric assay detecting PGE₂ formation. Protein concentrations were normalised per sample.
Statistical analysis: Results were analysed using one-way ANOVA with Dunnett’s multiple comparison test (GraphPad Prism v10). Data expressed as mean ± SEM; p < 0.05 considered significant.
Results Cytokine inhibition: LPS stimulation increased IL-6 and TNF-α release 8–10 fold compared with unstimulated controls. IBU-107 reduced IL-6 levels by 37%, 61%, and 68% at 1, 10, and 50 μM respectively (p < 0.05 vs control at ≥10 μM). Comparable TNF-α inhibition was observed, with no evidence of cytotoxicity.
COX activity: At 50 μM, IBU-107 inhibited COX-2–mediated PGE₂ synthesis by 73% (vs. 59% for ibuprofen, p = 0.04). No significant difference in COX-1 inhibition between compounds.
Discussion IBU-107 demonstrated concentration-dependent suppression of pro-inflammatory cytokine release and selective inhibition of COX-2 activity. While the magnitude of effect was modest, the data suggest potential pharmacological differentiation from parent ibuprofen.
This ex vivo approach aligns with early translational pharmacology practices under UK ethical and regulatory standards, providing human-relevant mechanistic data prior to in vivo evaluation. The findings highlight the feasibility of small-scale human tissue studies under HRA and HTA oversight, without requiring a Clinical Trial Authorisation (CTA).
Limitations – Small sample size (n=6 donors) limits generalisability. – Ex vivo data may not fully predict in vivo pharmacodynamics. – Only COX and cytokine endpoints were assessed; no metabolite profiling performed.
Conclusion IBU-107 exhibited anti-inflammatory activity consistent with ibuprofen and modestly greater COX-2 selectivity in human PBMCs. This early mechanistic data supports further investigation under the UK preclinical pharmacology framework.