Enhanced Oral Absorption and Bioavailability of Ivermectin Through Amorphous Solid Dispersion Techniques

The purpose of this study was to develop a high-loading amorphous solid dispersion (ASD) of ivermectin to significantly enhance its oral absorption and bioavailability. Using a solvent method, we formulated a novel ternary ASD with polyvinylpyrrolidone PVPK30 and Poloxamer 188 (P188) in a 1:0.5:1.5 ratio of drug to PVPK30 to P188. We characterized the physicochemical properties of five ASD formulations through in vitro dissolution tests. The selected formulation, SD3, was further assessed using X-ray powder diffraction, scanning electron microscopy, differential scanning calorimetry, and pharmacokinetic studies in rats. Notably, SD3 enhanced drug loading more than 30-fold compared to commercial tablets. SD3 exhibited significantly faster dissolution rates and maintained an amorphous state that remained stable after two months of storage at 4°C. Pharmacokinetic analysis at a 20 mg/kg oral dose in rats showed that SD3 achieved the highest maximum concentration (Cmax), plasma exposure (AUC), and oral bioavailability compared to the pure drug and commercial tablets. The assessment of the oral absorption rate constant (Ka) revealed an increased Ka and intestinal permeability through this ASD, elucidating the possible mechanism behind these improvements.