Unlocking the Potential: Synergistic Effects of Solid SNEDDS and Lyophilized Solid Dispersion to Enhance Stability...

Among lipid-based formulations, self-nanoemulsifying drug delivery systems (SNEDDS) have captured a spotlight, captivating both academia and the pharmaceutical industry. These remarkable formulations offer a valuable option, yet their liquid form presents certain challenges for delivering poorly soluble drugs. Ensuring compatibility with capsule shells, maintaining physical and chemical stability, and understanding their impact on lipolysis remain vital areas of exploration. Therefore, the incorporation of this liquid formulation into a solid dosage form (S-SNEDDS) is compelling and desirable. S-SNEDDSs, prepared by adsorption, enhances formulation stability but retards drug dissolution. This study aims to design drug-free solid S-SNEDDS + solid dispersion (SD) as a novel combination to enhance cinnarizine (CN) stability upon storage while maintaining enhanced drug dissolution.

Drug-free liquid SNEDDSs were solidified using Neusilin® US2 at a 1:1 ratio. CN-SDs were prepared using freeze-drying technology. The SDs that were developed underwent characterization using various techniques, including scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray powder diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). In vitro lipolysis studies were conducted to evaluate the effect of the combined system on the performance of the formulation upon exposure to enzymes within biorelevant media.

In agreement with the DSC and XRD results, FTIR confirmed the amorphization of CN within the freeze-dried solid dispersion (FD-SD) systems. The in vitro lipolysis studies showed that the drug-free S-SNEDDS + SD combination was able to maintain a significant portion of the initial CN in solution even in the presence of lipase for up to 30 min. The accelerated stability studies showed that the drug-free S-SNEDDS + SD combination maintained 96% intact CN in an amorphous state and more than 90% release at pH 1.2 for up to 6 months, while the dissolution profile at pH 6.8 showed a significant drop in CN release upon storage.

Overall, the developed formulation could be a potential technique to enhance the dissolution of weakly basic drugs that possess challenging stability limitations.