Physico-chemical and solid-state characterization of secnidazole.

Secnidazole (hydroxy-2-propyl)-l-methyl-2-nitro-5-imidazole) is an antimicrobic agent. This drug has pharmacological activity against intestinal and hepatic amebiasis, giardiasis and vaginal trichomoniasis. This paper shows the physicochemical parameters of secnidazole determined during a preformulation study. The determination of the apparent partition coefficient and the profile of solubility in dependence of pH demonstrate the basic characteristic of the drug. The dissolution assay was performed to evaluate its behavior in water. For this purpose, a new spectrophotometric method, which was linear from 5 to 15 microg/ml, sensitive, precise, accurate and selective, was validated to assay the bulk drug. The evaluation of higroscopicity revealed that the drug is unstable above 54% of relative humidity. Rheological properties, such as porosity, tapped and bulk densities and percentage of compressibility were calculated. Results show a bad rheological characteristic for this drug. DSC curves do not show any physical interaction between the drug and the excipients in the compatibility studies.