Design and in vitro characterization of ivermectin nanocrystals liquid formulation based on a top-down approach

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.

Formulation and optimization of ivermectin nanocrystals for enhanced topical delivery

The increasing resistance to antiparasitic drugs and limited availability of new agents highlight the need to improve the efficacy of existing treatments. Ivermectin (IVM) is commonly used for parasite treatment in humans and animals, however its efficacy is not optimal and the emergence of IVM-resistant parasites presents a challenge. In this context, the physico-chemical characteristics of IVM were modified by nanocrystallization to improve its equilibrium water-solubility and skin penetration, potentially improving its therapeutic effectiveness when applied topically. IVM-nanocrystals (IVM-NC) were prepared using microfluidization technique. The impact of several process/formulation variables on IVM-NC characteristics were studied using D-optimal statistical design. The optimized formulation was further lyophilized and evaluated using several in vitro and ex vivo tests. The optimal IVM-NC produced monodisperse particles with average diameter of 186 nm and polydispersity index of 0.4. In vitro results showed an impressive 730-fold increase in the equilibrium solubility and substantial 24-fold increase in dissolution rate. Ex vivo permeation study using pig's ear skin demonstrated 3-fold increase in dermal deposition of IVM-NC. Additionally, lyophilized IVM-NC was integrated into topical cream, and the resulting drug release profile was superior compared to that of the marketed product. Overall, IVM-NC presents a promising approach to improving the effectiveness of topically applied IVM in treating local parasitic infections.

Telmisartan Nanosuspension for Inhaled Therapy of COVID-19 Lung Disease and Other Respiratory Infections

Vaccine hesitancy and the occurrence of elusive variants necessitate further treatment options for coronavirus disease 2019 (COVID-19). Accumulated evidence indicates that clinically used hypertensive drugs, angiotensin receptor blockers (ARBs), may benefit patients by mitigating disease severity and/or viral propagation. However, current clinical formulations administered orally pose systemic safety concerns and likely require a very high dose to achieve the desired therapeutic window in the lung. To address these limitations, we have developed a nanosuspension formulation of an ARB, entirely based on clinically approved materials, for inhaled treatment of COVID-19. We confirmed in vitro that our formulation exhibits physiological stability, inherent drug activity, and inhibitory effect against SARV-CoV-2 replication. Our formulation also demonstrates excellent lung pharmacokinetics and acceptable tolerability in rodents and/or nonhuman primates following direct administration into the lung. Thus, we are currently pursuing clinical development of our formulation for its uses in patients with COVID-19 or other respiratory infections.

Ivermectin: recent approaches in the design of novel veterinary and human medicines

Ivermectin (IVM) is a drug widely used in veterinary and human medicine for the management of parasitic diseases. Its repositioning potential has been recently considered for the treatment of different diseases, such as cancer and viral infections. However, IVM faces some limitations to its formulations due to its low water solubility and bioavailability, along with reports of drug resistance. In this sense, novel technological approaches have been explored to optimize its formulations and/or to develop innovative medicines. Therefore, this review discusses the strategies proposed in the last decade to improve the safety and efficacy of IVM and to explore its novel therapeutic applications. Among these technologies, the use of micro/nano-drug delivery systems is the most used approach, followed by long-acting formulations. In general, the development of these novel formulations seems to run side by side in veterinary and human health, showing a shared interface between the two areas. Although the technologies proposed indicate a promising future in the development of innovative dosage forms containing IVM, its safety and therapeutic targets must be further evaluated. Overall, these approaches comprise tailoring drug delivery profiles, decreasing the risks of developing drug resistance, and supporting the application of IVM for reaching different therapeutic targets.

Nanoparticles for antiparasitic drug delivery

As an emerging novel drug carrier, nanoparticles provide a promising way for effective treatment of parasitic diseases by overcoming the shortcomings of low bioavailability, poor cellular permeability, nonspecific distribution and rapid elimination of antiparasitic drugs from the body. In recent years, some kinds of ideal nanocarriers have been developed for antiparasitic drug delivery. In this review, the progress of the enhanced antiparasitic effects of different nanoparticles payload and their influencing factors were firstly summarized. Secondly, the transport and disposition process in the body were reviewed. Finally, the challenges and prospects of nanoparticles for antiparasitic drug delivery were proposed. This review will help scholars to understand the development trend of nanoparticles in the treatment of parasitic diseases and explore strategies in the development of more efficient nanocarriers to overcome the difficulty in the treatment of parasite infections in the future.

Orally Administrable Therapeutic Synthetic Nanoparticle for Zika Virus

The spread of Zika virus (ZIKV) infection across the USA and various countries in the last three years will not only have a direct impact on the U.S. health care system but has caused international concerns as well. The ultimate impact of ZIKV infection remains to be understood. Currently, there are no therapeutic or vaccine options available to protect those infected by ZIKV. The drug ivermectin (IVM) was found to be a viable agent for the prevention of transmission of ZIKV. Ivermectin is unstable in the presence of water and does not remain in adequate concentration in the human bloodstream to be effective in treatment for ZIKV. Biodegradable nanoparticles would aid in the delivery of ivermectin by providing a high enough concentration of drug and ensuring the drug is gradually released to maintain an appropriate level in the body. The overall goal of this study was to develop and optimize an orally administrable nanoformulation of IVM which can circulate in the blood for a long period for efficient delivery. To achieve the goal, we synthesized and optimized a synthetic nanoformulation of IVM for oral use which can cross the intestinal epithelial barrier to enter the bloodstream. Our studies documented that when delivered with the synthetic nanoparticle (NP), IVM can be accumulated in the blood at a higher concentration and preliminary studies highlighted that NP delivered IVM has the ability to target nonstructural 1 protein of ZIKV. For potential clinical relevance, long-term storable formulation of IVM-nanoparticle in dry powder state for inclusion in a capsule form and cryoprotectant containing frozen forms revealed promising findings. Further, our preliminary in vitro studies documented that ivermectin crosses the placental barrier, thus making it unsafe for the pregnant ZIKV population, whereas the ivermectin-loaded nanoparticle did not show any significant placental barrier crossing, thus indicating its potential suitability for such population. We envision that this work will fill a great unmet need by developing safer and more effective therapies for the treatment of viral infections, including ZIKV.