Physical and pharmacokinetic characterization of Soluvec™, a novel, solvent-free aqueous ivermectin formulation

Formulation and optimization of pH-sensitive nanocrystals for improved oral delivery

The challenge of low water solubility in pharmaceutical science profoundly impacts drug absorption and therapeutic effectiveness. Nanocrystals (NC), consisting of drug molecules and stabilizing agents, offer a promising solution to enhance solubility and control release rates. In the pharmaceutical industry, top-down techniques are favored for their flexibility and cost-effectiveness. However, increased solubility can lead to premature drug dissolution in the stomach, which is problematic due to the acidic pH or enzymes. Researchers are exploring encapsulating agents that facilitate drug release at customized pH levels as a valuable strategy to address this. This study employed wet milling and spray drying techniques to create encapsulated NC for delivering the drug to the intestinal tract using the model drug ivermectin (IVM). Nanosuspensions (NS) were efficiently produced within 2 h using NanoDisp®, with a particle size of 198.4 ± 0.6 nm and a low polydispersity index (PDI) of 0.184, ensuring uniformity. Stability tests over 100 days at 4 °C and 25 °C demonstrated practical viability, with no precipitation or significant changes observed. Cytotoxicity evaluations indicated less harm to Caco-2 cells compared to the pure drug. Furthermore, the solubility of the NC increased by 47-fold in water and 4.8-fold in simulated intestinal fluid compared to the pure active compound. Finally, dissolution tests showed less than 10% release in acidic conditions and significant improvement in simulated intestinal conditions, promising enhanced drug solubility and bioavailability. This addresses a long-standing pharmaceutical challenge in a cost-effective and scalable manner.

Co-Processed Crystalline Solids of Ivermectin with Span® 60 as Solubility Enhancers of Ivermectin in Natural Oils

Despite being discovered over five decades ago, little is still known about ivermectin. Ivermectin has several physico-chemical properties that can result in it having poor bioavailability. In this study, polymorphic and co-crystal screening was used to see if such solid-state modifications can improve the oil solubility of ivermectin. Span® 60, a lipophilic non-ionic surfactant, was chosen as co-former. The rationale behind attempting to improve oil solubility was to use ivermectin in future topical and transdermal preparations to treat a range of skin conditions like scabies and head lice. Physical mixtures were also prepared in the same molar ratios as the co-crystal candidates, to serve as controls. Solid-state characterization was performed using X-ray powder diffraction (XRPD), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The FTIR spectra of the co-crystal candidates showed the presence of Span® 60's alkyl chain peaks, which were absent in the spectra of the physical mixtures. Due to the absence of single-crystal X-ray data, co-crystal formation could not be confirmed, and therefore these co-crystal candidates were referred to as co-processed crystalline solids. Following characterization, the solid-state forms, physical mixtures and ivermectin raw material were dissolved in natural penetration enhancers, i.e., avocado oil (AVO) and evening primrose oil (EPO). The co-processed solids showed increased oil solubility by up to 169% compared to ivermectin raw material. The results suggest that co-processing of ivermectin with Span® 60 can be used to increase its oil solubility and can be useful in the development of oil-based drug formulations.