Pipemidic acid-thiadiazole hybrid system with antibacterial and anti-inflammatory effects

Abstract

A system comprising pipemidic acid-1,3,4-thiadiazole hybrid derivatives with a thiadiazole group at position C-6 of the pipemidic acid skeleton, synthesized and structurally determined by IR-, 1 H-NMR-, 13 Confirmed by C-NMR and mass spectrometry.

Description

Field of invention

[0001] The invention relates to medicinal chemistry systems and pharmaceutical compositions that utilize pipemidic acid-1,3,4-thiadiazole hybrids as a device-like therapeutic platform and enable antibacterial efficacy as well as a COX-2-mediated anti-inflammatory effect with standardized characterization. Background of the invention

[0002] Thiadiazole scaffolds have proven to be versatile pharmacophores with broad antimicrobial activity. Structure-activity relationship analyses reveal substituent effects that can enhance efficacy against both Gram-positive and Gram-negative bacterial strains. Reviews and original studies confirm that 1,3,4-thiadiazole derivatives can outperform standard antibiotics in various assays. This motivates hybridization with quinolone scaffolds to enhance DNA gyrase / topoisomerase inhibition through interactions with heteroaromatic pharmacophores. Parallel studies have identified thiadiazole derivatives as selective COX-2 inhibitors with docking-validated interactions in the secondary binding pocket of COX-2. This suggests anti-inflammatory potential while minimizing COX-1-mediated gastric effects.Pipemidic acid derivatives exhibited enhanced antimicrobial activity upon appropriate heterocycle conjugation. This suggests that modifications at the C-6 atom can selectively influence antibacterial profiles, consistent with previous pipemidic acid hybrid studies. A standardized system encompassing synthesis, structure elucidation, and bioactivity assessment remains needed to provide pipemidic acid-thiadiazole hybrids with improved minimum inhibitory concentrations (MICs) and quantifiable COX-2 inhibition for translational development.

[0003] Summary of the invention: The invention relates to a pipemidic acid hybrid system with a 1,3,4-thiadiazole unit at position C-6 for generating the derivatives T1-T3, which were developed for dual antibacterial and anti-inflammatory activity. Structural identity was verified by IR, 1H / 13C NMR, and MS spectroscopy. In standardized antimicrobial tests on various bacterial strains, T1 and T2 achieved MIC values ​​of approximately 10 µg / ml, exceeding a ciprofloxacin reference substance value of approximately 16 µg / ml under identical conditions. This reflects an increase in efficacy consistent with the SAR trends of thiadiazoles.

[0004] The system also includes COX-2 inhibition profiling to assess anti-inflammatory activity. Under test conditions consistent with established thiadiazole-COX-2 studies and docking paradigms, T3 exhibits inhibition of approximately 42.1%. The presented platform combines scalable synthesis with directly testable characterization and a test procedure applicable to both drug discovery and quality control for evaluating hybrid derivatives for further development. Detailed description

[0005] The system comprises synthetic routes for the C-6 functionalization of pipemidic acid with a 1,3,4-thiadiazole fragment. Heterocycle formation and coupling strategies are employed, optimized for yield and purity of T1-T3. Work-up of the reactions aims to remove inorganic byproducts and residual reagents to analytical purity. Structural elucidation is achieved using Fourier-transform IR spectroscopy to identify characteristic thiadiazole and quinolone vibrations, 1H / 13C NMR spectroscopy to assign diagnostic aromatic and heteroatom-near signals, and mass spectrometry to verify molecular ions and fragmentation patterns consistent with the hybrid architecture. The compositions are prepared as ready-to-use substances or formulated prototypes, enabling reproducible evaluation in antibacterial and COX-2 assays without interfering excipients.

[0006] Antibacterial testing included representative Gram-positive and Gram-negative strains. The minimum inhibitory concentration (MIC) was determined by broth microdilution or agar dilution according to standard protocols. The observed MIC values ​​for T1 and T2 of approximately 10 µg / ml indicate superior inhibition compared to ciprofloxacin at approximately 16 µg / ml under comparable conditions. These results are consistent with reports that certain substituents on thiadiazole rings modulate efficacy and often enhance efficacy against Gram-negative bacteria when a balance of hydrophobicity and electron-withdrawing properties is present. COX-2 evaluation for T3 was performed according to in vitro enzyme inhibition protocols analogous to studies with thiadiazole COX-2 inhibitors.An inhibition of approximately 42.1% was observed, indicating docking-mediated interactions in the COX-2 binding pocket, as observed for sulfonamide-containing thiadiazoles.

[0007] The system architecture is designed for platform development: T-series compounds are varied at the thiadiazole ring and linker to optimize activity, while the pipemide core supports quinolone-class antibacterial mechanisms. SAR cycles are based on the thiadiazole antibacterial literature from 2020–2025. Comparative profiling includes time-kill kinetics, post-antibiotic effect, and preliminary cytotoxicity tests to contextualize MIC data in terms of therapeutic indices, in line with current thiadiazole trial procedures. Prototype formulations (e.g., DMSO stock solution for assays, simple oral / intravenous preformulations for follow-up) are planned to transfer the drugs into dose-relevant assays while maintaining chemical integrity.

[0008] Production scalability encompasses batch synthesis with quality controls for identity, purity, and residual solvents, and establishes analytical specifications based on spectral fingerprints and chromatographic purity thresholds to ensure reproducible bioassay results. Data collection and reporting follow standardized templates used in thiadiazole antibiotic and COX-2 research to facilitate benchmarking and regulatory-compliant documentation for further development.

Claims

[1] A system comprising pipemidic acid-1,3,4-thiadiazole hybrid derivatives with a thiadiazole group at position C-6 of the pipemidic acid skeleton, synthesized and structurally determined by IR, 1 H-NMR-, 13 Confirmed by C-NMR and mass spectrometry. [2] System according to claim 1, wherein the antibacterial study shows that the derivatives T1 and T2 exhibit minimum inhibitory concentrations of approximately 10 µg / ml against tested bacterial strains under standardized protocols, thus exceeding the efficacy of ciprofloxacin at approximately 16 µg / ml. [3] System according to claim 1, wherein the anti-inflammatory study shows that the derivative T3 achieves an inhibition of cyclooxygenase-2 of approximately 42.1% under in vitro test conditions analogous to established thiadiazole-COX-2 studies. [4] System according to claim 1, wherein the variation of the substituents on the thiadiazole ring and the linker group enables structure-activity optimization for dual antibacterial and anti-inflammatory profiles within the framework of current SAR knowledge of thiadiazoles.