Virtual bioequivalence studies (VBE) can assess the similarity and potential differences in pharmacokinetic and clinical performance between test and reference formulations based on the translational relationship between in vitro, in silico, and in vivo. The crucial data from clinical trials can be delivered with the help of virtual bioequivalence research, which will speed up the creation of novel and generic medications. Virtual bioequivalence study regulation, however, has not yet reached its complete development. The current status of VBE studies in the market is booming and many pharmaceutical industries have started adapting to its benefits in submitting bioequivalence results for approval from regulatory bodies. FDA had regulated the guidelines for virtual bioequivalence, which the various regulatory agencies accept for the approval of filing ANDA. The importance of implementing VBE has benefited at present in saving cost and time; low workforce and failures can be neglected. Determining the framework for virtual bioequivalence studies for all medications and discussing the potential uses of virtual bioequivalence in the future to support the waiver and optimization of in vivo clinical trials are the main objectives of this review article.

Introduction: This review explores the design principles, sensor mechanisms, and propulsion systems of nanorobots, highlighting their applications in targeted drug delivery, disease monitoring, and broader biomedical fields. The objective is to provide a comprehensive overview of how nanorobots transform pharmaceutical delivery systems and precision therapy. Methodology: A structured literature search was conducted using electronic databases, including PubMed, Scopus, and Web of Science. Keywords such as Nanorobots, Nanorobot propulsion, Biosensors, Magnetically driven nanorobots, Electric field-driven nanorobots, Biomedical applications, and Enzyme-driven nanorobots were used. Articles published between 2010 and 2024 were considered. Inclusion criteria involved peer-reviewed articles focusing on nanorobot design, propulsion systems, sensor mechanisms, and clinical applications. Non-English articles and non-peer-reviewed content were excluded. Results: A total of 212 relevant studies were initially identified through a comprehensive search across PubMed, Scopus, Web of Science, and Google Scholar. After applying inclusion and exclusion criteria, 94 studies were selected for final analysis, focusing on the integration of sensors, propulsion systems, and energy sources in nanorobots. Discussion: The review revealed that nanorobots utilize advanced sensor systems (nanocantilevers and biosensors) for molecular recognition and site-specific targeting. These sensors detect biochemical and mechanical changes, aiding precise navigation. Powered by external forces (magnetic, electric, light, ultrasound) or internal biochemical energy (enzymatic or chemical reactions), propulsion mechanisms enable controlled movement and drug delivery. Nanorobots constructed from silicon, polymers, and piezoelectric compounds exhibit functional adaptability. Their applications span targeted drug delivery, oncology, neurosurgery, vascular medicine, and environmental remediation. Conclusion: Nanorobots represent a trailblazing pharmaceutical innovation, offering highly specific, efficient, and minimally invasive drug delivery and disease monitoring capabilities. Their combination of biosensing and propulsion mechanisms enhances targeted delivery and clinical efficacy. Continued development in nanorobotic systems holds the potential to revolutionize clinical treatments and improve patient outcomes across multiple therapeutic domains.

Introduction: Diabetic foot ulcers (DFUs) are difficult to treat due to biofilm formation, poor drug penetration, and elevated wound pH. This study aimed to develop a pH-responsive solid lipid nanoparticle (SLN)-loaded hydrogel for targeted ciprofloxacin delivery using a Quality-byDesign (QbD) approach. Methods: SLNs were formulated via solvent emulsification–ultrasonication and optimized using a Box–Behnken design to study the effects of lipid concentration, surfactant concentration, and sonication time on particle size and entrapment efficiency. Optimized SLNs were coated with pHsensitive Eudragit L100 and incorporated into a Carbopol 974P hydrogel. The formulation was evaluated for particle size, zeta potential, entrapment efficiency, rheology, spreadability, occlusion, drug release, antimicrobial activity, and three-month stability. Results: Optimized SLNs showed a particle size of 141.24 ± 2.19 nm, polydispersity index (PDI) 0.236 ± 0.019, zeta potential −26.28 ± 1.31 mV, and an entrapment efficiency of 62.55 ± 1.07%. The hydrogel exhibited pseudoplastic flow, good spreadability, and enhanced occlusivity. Drug release was sustained and pH dependent, with greater release at pH 7.4 than at pH 5.5. The SLNloaded hydrogel showed stronger antibacterial activity than the free drug gel against E. coli, S. aureus, and P. aeruginosa. The formulation remained stable for three months at 4 °C with minimal variation in physicochemical properties. Discussion: The pH-responsive coating enabled targeted release in alkaline DFUs, and the SLN– hydrogel system improved drug retention, antibacterial activity, and formulation stability. Conclusion: A stable, pH-responsive SLN-loaded hydrogel was successfully developed, demonstrating strong potential for targeted topical treatment of biofilm-associated DFUs and future clinical application.