In vitro anti-inflammatory activity using thermally inhibiting protein denaturation of egg albumin and antimicrobial activities of some organic solvents

Abstract

This study was to investigate the anti-inflammatory and antibacterial activities of some organic solvents used in drug delivery systems including N-methyl pyrrolidone (NMP), 2-pyrrolidone (2-PYR), dimethyl sulfoxide (DMSO), ethanol, tetraglycol, polyethylene glycol 400 (PEG 400) and propylene glycol (PG). Anti-inflammation was evaluated by inhibition of heat-induced protein denaturation of egg albumin model, and the reference drug was diclofenac sodium. NMP, 2-PYR and diclofenac sodium expressed concentration-dependent inhibition with 50% inhibitory concentration (IC50) values of 4.82%v/v (49.35 mg/ml), 4.83%v/v (52.29 mg/ml) and 736.50 µg/ml, respectively. DMSO, tetraglycol, and PEG400 showed some anti-inflammatory activity. Ethanol and PG displayed a dose-dependent inflammation effect by promoting more protein denaturation. NMP, 2-PYR, DMSO, tetraglycol, and PG had antibacterial and antifungal activities against all test microorganisms. The antibacterial, especially against Porphyromonas gingivalis, and antifungal activities of both NMP and 2-PYR were apparently evident. Triacetin and PEG400 showed only antifungal and some antibacterial activities, respectively, whereas absolute ethanol had no antimicrobial activity. Thus, NMP and 2-PYR were regarded as potential solvents for in situ forming gel (ISG).