Abstract

Background: Adsorption-based solidification is a solvent-free route to prepare a solid form of self-nanoemulsifying drug delivery systems (SNEDDS). However, the limited drug loading and the low bulk density of the porous carrier restrict its pharmaceutical applicability. This study developed a pH-modulated SNEDDS in which sodium carbonate modulates the pH of the formulation microenvironment. Atorvastatin calcium and glibenclamide were used as high-dose and low-dose weakly acidic model drugs. Methods: The SNEDDS components were selected by solubility and emulsification screening. Sodium carbonate was incorporated as the pH-modulating agent, and liquid formulations were solidified by adsorption onto Syloid. The formulations were characterized by FTIR, PXRD, and SEM, and evaluated by an in vitro dissolution study. Results: The selected liquid SNEDDS (L-SNEDDS) consisted of polysorbate 80, polyethylene glycol 400, and glyceryl monocaprylate. Sodium carbonate increased the microenvironmental pH from 5.31 to 6.83. This increased drug loading by approximately 2.0-fold for atorvastatin calcium and 3.0-fold for glibenclamide. FTIR showed no chemical interaction between the components. SEM confirmed adsorption within the porous carrier, whereas PXRD showed no detectable drug crystallinity. The increased loading reduced the number of capsules required per dose from two to one for atorvastatin calcium and from four to one for glibenclamide. In vitro dissolution confirmed that pH modulation did not compromise drug dissolution despite the reduced SNEDDS content per dose. Conclusions: pH modulation with sodium carbonate enabled single-capsule dosing and provided a solvent-free route to boost drug loading for the two investigated model drugs.

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