Objectives: To formulate a poorly water soluble, antidiabetic drug, gliclazide, in vegetable oil based self-emulsifying delivery system (SEDDS), as a trial to improve its dissolution and hence its bioavailability.
Material and methods: Solubility of gliclazide was investigated in different vegetable oils, surfactants and co-surfactants. The system was selected and the self-emulsification region was identified. Drug loaded SEDDS was prepared and evaluated in terms of emulsification time, phase separation, droplet size and rate of drug dissolution. The formulation that showed good self-emulsifying properties, acceptable droplet size and high % drug release was further processed into solid- SEDDS by physical mixing with varying proportions of a mixture (2:1) of microcrystalline cellulose and lactose and characterized for crystalline, droplet size and in vitro drug dissolution properties.
Results and Conclusions: Formulation of gliclazide in liquid and solid SEDDS using olive oil resulted in significant (P< 0.05) improvement in its dissolution properties. Both differential scanning calorimetry and x-ray diffraction studies demonstrated presence of gliclazide in molecular state in all the prepared solid formulations. Solid SEDDS of gliclazide containing lower proportion of adsorbent (G1) had comparable dissolution properties with its liquid form. Thus formulation of gliclazide in solid self-emulsifying system may be a promising strategy to improve its dissolution properties.
Key words: gliclazide; solid-SEDDS; ternary phase diagram; dissolution; olive oil
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