Molecular complexes of aspirin with humic acid extracted from shilajit and their characterization

Aspirin possesses antipyretic, anti-inflammatory, analgesic and anti-aggregatory activity. The acetylsalicylic acid molecule has a carboxyl group and an ester group. The ester group can be easily hydrolyzed, which reduces the medicinal value and causes side effects on humans. The aim of the present study was to prepare solid complexes between aspirin and humic by lyophilization and solvent evaporation technique in the molar ratio 1:1 and 1:2. Molecular interaction between aspirin and humic acid were studied by DSC, XRD, FT-IR and scanning electron microscopy. This technique clearly demonstrated the existence of solid inclusion complex formation. The lyophilized complex in the molar ratio 1:2 showed enhanced stability and dissolution rates of aspirin significantly. A highly significant (p < 0.05) anti-inflammatory action of the treatment of optimized freeze dried (1:2) aspirin complex with humic acid was evidenced by inhibition of rat paw edema and anti-ulcerogenic action was measured by lowest score (0.63 ± 0.10) with significant reduction in ulceration as compared to aspirin alone.