Anti-inflammatory and analgesic activity based on polymorphism of cedrol in mice

Abstract

Alternate forms of drug crystals display different physicochemical properties. These include stability, dissolution rate, bioavailability and solubility, which can affect pharmacokinetics and pharmacodynamics. It is therefore important to compare the crystal forms of cedrol to obtain optimal anti-inflammatory and analgesic effects. This study, for the first time, obtained and reports three novel forms (I-III) of cedrol polymorphs. The three forms of cedrol were recrystallized from seven organic solvents by slow cooling or volatilization and identified by thermal analysis, fourier transform infrared spectroscopy, scanning electron microscopy and powder X-ray diffraction analysis. Form I originated from acetone and cyclohexane. Form II was obtained from ethanol, ethyl acetate, acetonitrile and n-hexane. Form III was recrystallized from methanol. The anti-inflammatory and analgesic activities of the three crystalline forms were evaluated by acetic acid induced writhing in mice, the hot plate method, carrageenan induced mouse paw edema models, Xylene-induced mouse ear edema models and cotton pellet-induced mouse granuloma models. Experimental results revealed that the highest performance was achieved from Form I. These findings are of great significance during the early research study of cedrol polymorphs.

Keywords: Analgesic; Anti-inflammatory; Cedrol; Polymorphism.