Development and in vitro evaluation of ^99mTc-labeled DTPA-functionalized mesoporous silica nanoparticles for targeted delivery of cyclophosphamide

In recent years, the use of nanoparticles (NPs) for the delivery of therapeutic and targeted drugs has gained significant attention from both researchers and the pharmaceutical industry. Among these drug delivery systems, mesoporous silica nanoparticles (MSNs) have been widely utilized in healthcare applications due to their biocompatibility and low toxicity. The porous structure of MSNs enables efficient drug loading and controlled release at the target site. This study aimed to synthesize MSNs loaded with cyclophosphamide (CPH), an anticancer drug, and radiolabel them with Technetium-99 m (⁹⁹ᵐTc) to evaluate their biological behavior in vitro. Various parameters, including particle size, morphology, and drug encapsulation efficiency, were assessed to determine optimal synthesis conditions. Nanoparticles were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Dynamic Light Scattering (DLS), and Scanning Electron Microscopy (SEM). DLS analysis revealed that the hydrodynamic radius of the synthesized MSNs was 125 ± 3.4 nm, while SEM images confirmed their spherical shape, with sizes ranging between 55 and 70 nm. Quality control studies of radiolabeled CPH-loaded MSNs (⁹⁹ᵐTc-MSN-CPH) were conducted using Thin Layer Radiochromatography (TLRC), demonstrating a radiolabeling yield of 99.82 ± 0.25%. Further in vitro studies, including cytotoxicity and cellular uptake assays, were performed using MCF-7 and MDA-MB-231 breast cancer cell lines. Results indicated similar uptake of ⁹⁹ᵐTc-MSN-CPH in both cell types. The findings suggest that the synthesized nanostructure could advance radiolabeled nanotheranostic systems using ⁹⁹ᵐTc, with potential applications in cancer diagnosis and treatment.