Fujicalin®-based solid supersaturable self-emulsifying drug delivery system (S-SEDDS) of tacrolimus for enhanced dissolution rate and oral absorption

Abstract

The aim of the study was to formulate the solid dosage form of the supersaturable self-emulsifying drug delivery system (S-SEDDS) for tacrolimus, a poorly water-soluble immunosuppressant, to enhance the dissolution rate and oral absorption. A solid formulation was prepared by adsorbing the liquid S-SEDDS onto porous carriers including Fujicalin® (dibasic calcium phosphate). Macroscopic observation using scanning electron microscopy and drug crystallinity determination using X-ray powder diffraction revealed that the calcineurin inhibitor was effectively held within the intact porous carriers in a solubilized form. In an in vitro dissolution test in simulated gastric fluid (pH 1.2), there were no remarkable differences in the release rate and extent of dissolution between liquid and Fujicalin®-based solid S-SEDDS, achieving over 90 % drug release after 15 min. Moreover, the pharmacokinetic parameters for tacrolimus in the liquid and Fujicalin®-based solid S-SEDDS after oral administration at a dose of 5 mg/kg were statistically equivalent in rats (p > 0.05). This study suggests that solidification of liquid S-SEDDS using Fujicalin®, a soluble adsorbent in acidic medium, can be a promising approach to obtain the free-flowing powder form of liquid S-SEDDS while preserving the high and fast dissolution rate of the liquid self-emulsifying system. © 2015, The Korean Society of Pharmaceutical Sciences and Technology.