Particle Size Tailoring of Quercetin Nanosuspensions by Wet Media Milling Technique: A Study on Processing and Formulation Parameters

BACKGROUND: A large number of new substances have insufficient biopharmaceutical properties for oral administration caused by their slow dissolution rate and poor solubility. OBJECTIVE: The purpose of our experiment was to improve the physicochemical properties of a hydrophobic drug, quercetin, by the nanomilling approach. METHODS: Quercetin nanosuspensions were prepared using a wet-milling method followed by lyophilization. Stabilizer type and ratio, drug content, milling time, and bead size were identified as critical variables, and their impacts on quercetin particle size were assessed. The optimized nanocrystal was characterized by its morphology, crystallinity, molecular interactions, saturation solubility, and dissolution properties. RESULTS: At optimized process conditions of milling at 500 rpm for 18 cycles of grinding with 0.3 - 0.4 mm zirconium oxide beads, minimum particle size, and PDI values were 281.21 nm and 0.22, respectively. Nanocrystals showed rod-like nanostructures, and XRD scans confirmed a decrease in drug crystallinity. The optimized formulation showed increased solubility and dissolution rate, as well as good physical stability. CONCLUSIONS: Particle size reduction by media milling technique was an efficient method for the solubility enhancement of hydrophobic drugs.