Preparation and Evaluation of Mebendazole Microemulsion for Intranasal Delivery: an Alternative Approach for Glioblastoma Treatment.

Although mebendazole (MBZ) has demonstrated antitumor activity in glioblastoma models, the drug has low aqueous solubility and therefore is poorly absorbed. Considering that other strategies are needed to improve its bioavailability, the current study was aimed to develop and evaluate novel microemulsions of MBZ (MBZ-NaH ME) for intranasal administration. MBZ raw materials were characterized by FTIR, DSC, and XDP. Subsequently, the raw material that contained mainly polymorph C was selected to prepare microemulsions. Two different oleic acid (OA) systems were selected. Formulation A was composed of OA and docosahexaenoic acid (3:1% w/w), while formulation B was composed of OA and Labrafil M2125 (1:1% w/w). Sodium hyaluronate (NaH) at 0.1% was selected as a mucoadhesive agent. MBZ MEs showed a particle size of 209 nm and 145 nm, respectively, and the pH was suitable for nasal formulations (4.5-6.5). Formulation B, which showed the best solubility and rheological behavior, was selected for intranasal evaluation. The nasal toxicity study revealed no damage in the epithelium. Furthermore, formulation B improved significantly the median survival time in the orthotopic C6 rat model compared to the control group. Moreover, NIRF signal intensity revealed a decrease in tumor growth in the treated group with MBZ-MaH ME, which was confirmed by histologic examinations. Results suggest that the intranasal administration of mebendazole-loaded microemulsion might be appropriated for glioblastoma treatment. Graphical abstract.

Experimental-Theoretical Approach to the Adsorption Mechanisms for Anionic, Cationic, and Zwitterionic Surfactants at the Calcite-Water Interface.

The adsorption of surfactants (DTAB, SDS, and CAPB) at the calcite-water interface was studied through surface zeta potential measurements and multiscale molecular dynamics. The ground-state polarization of surfactants proved to be a key factor for the observed behavior; correlation was found between adsorption and the hard or soft charge distribution of the amphiphile. SDS exhibits a steep aggregation profile, reaching saturation and showing classic ionic-surfactant behavior. In contrast, DTAB and CAPB featured diversified adsorption profiles, suggesting interplay between supramolecular aggregation and desorption from the solid surface and alleviating charge buildup at the carbonate surface when bulk concentration approaches CMC. This manifests as an adsorption profile with a fast initial step, followed by a metastable plateau and finalizing with a sharp decrease and stabilization of surface charge. Suggesting this competition of equilibria, elicited at the CaCO3 surface, this study provides atomistic insight into the adsorption mechanism for ionic surfactants on calcite, which is in accordance with experimental evidence and which is a relevant criterion for developing enhanced oil recovery processes.