Aqueous Solubility Enhancement of Mirtazapine: Effect of Cosolvent and Surfactant

Abstract

The poor aqueous solubility of drugs is a challenging problem faced by pharmaceutical scientists in drug formulation. Cosolvency and micellization techniques have been severally used to enhance the solubility of poorly aqueous soluble drugs. Mirtazapine, a tetracyclic antidepressant used for the treatment of moderate to severe depression and anxiety, has very poor aqueous solubility. The objective of the study was to investigate the effect of solubilizing agents (cosolvents and surfactants) on the aqueous solubility of mirtazapine while envisaging that any significant improvement in its aqueous solubility could contribute towards alleviating the withdrawal symptoms often associated with the drug. The solubility of mirtazapine was determined at room temperature in aqueous mixtures of cosolvents (propylene glycol and polyethylene glycol 400) and surfactants (polysorbate 20, polysorbate 80 and sodium lauryl sulfate).