Nanocrystals and nanosuspensions have emerged as effective solutions for overcoming the formulation challenges of poorly water-soluble drugs. They offer a versatile platform for various therapeutic applications and can be integrated into drug delivery systems such as tablets, hydrogels, microneedles, and liposomes. Recent advancements in nanocrystal technology have enabled the development of formulations that enhance drug solubility, bioavailability, and targeted delivery. A case study on itraconazole nanosuspension-in-hydrogel formulation highlights the potential of these systems to improve drug release profiles and therapeutic outcomes. Nanocrystals and nanosuspensions are produced through two main methods: top-down (size reduction via milling or homogenization) and bottom-up (precipitation or spray-drying). Their high surface area and particle size distribution enhance dissolution rates and saturation concentrations, making them suitable for improving the oral bioavailability of poorly soluble drugs. These systems have been explored for various routes of administration, including oral, topical, ocular, and injectable, with applications in treating conditions such as cancer, HIV, and rheumatoid arthritis. Nanocrystal-loaded hydrogels and microneedles have shown promise in enhancing drug penetration and sustained release. In situ forming hydrogels provide controlled drug delivery and improved tissue penetration, while microneedles facilitate transdermal delivery with minimal invasiveness. Nanocrystals embedded in polymeric microparticles offer prolonged drug release and are suitable for long-term treatment of chronic diseases. Liposomal and surface-engineered nanocrystals have also been developed to improve drug targeting and reduce systemic toxicity, particularly in cancer therapy. Despite their potential, challenges such as stability, biocompatibility, and manufacturing scalability remain. However, ongoing research and clinical trials continue to explore the application of nanocrystals in various drug delivery systems. The integration of nanocrystals into novel formulations, such as hydrogels, microneedles, and liposomes, represents a promising direction for future drug delivery technologies. The field is evolving rapidly, with a growing number of clinical trials and formulations demonstrating the feasibility and effectiveness of nanocrystal-based drug delivery systems.Nanocrystals and nanosuspensions have emerged as effective solutions for overcoming the formulation challenges of poorly water-soluble drugs. They offer a versatile platform for various therapeutic applications and can be integrated into drug delivery systems such as tablets, hydrogels, microneedles, and liposomes. Recent advancements in nanocrystal technology have enabled the development of formulations that enhance drug solubility, bioavailability, and targeted delivery. A case study on itraconazole nanosuspension-in-hydrogel formulation highlights the potential of these systems to improve drug release profiles and therapeutic outcomes. Nanocrystals and nanosuspensions are produced through two main methods: top-down (size reduction via milling or homogenization) and bottom-up (precipitation or spray-drying). Their high surface area and particle size distribution enhance dissolution rates and saturation concentrations, making them suitable for improving the oral bioavailability of poorly soluble drugs. These systems have been explored for various routes of administration, including oral, topical, ocular, and injectable, with applications in treating conditions such as cancer, HIV, and rheumatoid arthritis. Nanocrystal-loaded hydrogels and microneedles have shown promise in enhancing drug penetration and sustained release. In situ forming hydrogels provide controlled drug delivery and improved tissue penetration, while microneedles facilitate transdermal delivery with minimal invasiveness. Nanocrystals embedded in polymeric microparticles offer prolonged drug release and are suitable for long-term treatment of chronic diseases. Liposomal and surface-engineered nanocrystals have also been developed to improve drug targeting and reduce systemic toxicity, particularly in cancer therapy. Despite their potential, challenges such as stability, biocompatibility, and manufacturing scalability remain. However, ongoing research and clinical trials continue to explore the application of nanocrystals in various drug delivery systems. The integration of nanocrystals into novel formulations, such as hydrogels, microneedles, and liposomes, represents a promising direction for future drug delivery technologies. The field is evolving rapidly, with a growing number of clinical trials and formulations demonstrating the feasibility and effectiveness of nanocrystal-based drug delivery systems.