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.

3D-Printed Gastroretentive Tablets Loaded with Niclosamide Nanocrystals by the Melting Solidification Printing Process (MESO-PP).

Niclosamide (NICLO) is a recognized antiparasitic drug being repositioned for Helicobacter pylori. The present work aimed to formulate NICLO nanocrystals (NICLO-NCRs) to produce a higher dissolution rate of the active ingredient and to incorporate these nanosystems into a floating solid dosage form to release them into the stomach slowly. For this purpose, NICLO-NCRs were produced by wet-milling and included in a floating Gelucire l3D printed tablet by semi-solid extrusion, applying the Melting solidification printing process (MESO-PP) methodology. The results obtained in TGA, DSC, XRD and FT-IR analysis showed no physicochemical interactions or modifications in the crystallinity of NICLO-NCR after inclusion in Gelucire 50/13 ink. This method allowed the incorporation of NICLO-NCRs in a concentration of up to 25% w/w. It achieved a controlled release of NCRs in a simulated gastric medium. Moreover, the presence of NICLO-NCRs after redispersion of the printlets was observed by STEM. Additionally, no effects on the cell viability of the NCRs were demonstrated in the GES-1 cell line. Finally, gastroretention was demonstrated for 180 min in dogs. These findings show the potential of the MESO-PP technique in obtaining slow-release gastro-retentive oral solid dosage forms loaded with nanocrystals of a poorly soluble drug, an ideal system for treating gastric pathologies such as H. pylori.

Design and Development of Sublingual Printlets Containing Domperidone Nanocrystals Using 3D Melting Solidification Printing Process (MESO-PP).

Domperidone (DOM) is a drug commonly used to treat nausea and vomiting, as well as gastrointestinal disorders. However, its low solubility and extensive metabolism pose significant administration challenges. In this study, we aimed to improve DOM solubility and avoid its metabolism by developing nanocrystals (NC) of DOM through a 3D printing technology-melting solidification printing process (MESO-PP)-to be delivered via a solid dosage form (SDF) that can be administered sublingually. We obtained DOM-NCs using the wet milling process and designed an ultra-rapid release ink (composed of PEG 1500, propylene glycol, sodium starch glycolate, croscarmellose sodium, and sodium citrate) for the 3D printing process. The results demonstrated an increase in the saturation solubility of DOM in both water and simulated saliva without any physicochemical changes in the ink as observed by DSC, TGA, DRX, and FT-IR. The combination of nanotechnology and 3D printing technology enabled us to produce a rapidly disintegrating SDF with an improved drug-release profile. This study demonstrates the potential of developing sublingual dosage forms for drugs with low aqueous solubility using nanotechnology and 3D printing technology, providing a feasible solution to the challenges associated with the administration of drugs with low solubility and extensive metabolism in pharmacology.

Nanocrystal-based 3D-printed tablets: Semi-solid extrusion using melting solidification printing process (MESO-PP) for oral administration of poorly soluble drugs.

This is the first report on the inclusion of nanocrystals (NCs) within 3D-printed oral solid dosage forms -3D-printed tablets or printlets- produced by the Melting Solidification Printing Process (MESO-PP) 3D printing technique. This method allowed the incorporation of albendazole (ABZ) nanocrystals in a concentration of up to 50% w/w, something not achieved in conventional tablets. An ink of PEG 1500/propylenegycol was used as a carrier and no physicochemical interactions or crystallinity modifications were observed due to the inclusion of ABZ-NCs into the ink, as demonstrated by TGA, DSC, XRD and FT-IR. In particular, the relative crystallinity of the ink loaded with NCs was 97.8% similar to the physical mixture of the components. Moreover, the presence of NCs was observed in the surface and matrix of the printlets by SEM. In addition, the printlet NCs demonstrated to be more effective than NCs included in hard gelatin capsules in improving drug dissolution in HCl 0.1 N. The particle size, crystallinity and chemical stability of the nanocrystals was maintained before and after 180 days of storage. Thus, these findings exhibit relevant pharmaceutical potential for developing stable, fast-release, oral, solid dosage forms of poorly soluble drugs combining 3D printing and nanocrystals. Additionally, this technique could be applied for printing objects using different types of nanocrystals embedded in low melting temperature polymers.