Stimuli-Responsive Polymers

The present study compares three colon-targeted drug delivery systems; Eudragit S100-coated polymeric tablets, PLGA nanoparticles, and alginate hydrogel microspheres, developed for the controlled release of 5-Fluorouracil (5-FU). Each formulation was prepared and optimized using distinct carriers and evaluated under simulated gastrointestinal (GI) conditions to assess their physicochemical characteristics, release behaviour, and stability. The formulations were characterized for particle size, surface charge, encapsulation efficiency, and swelling index. Morphological analysis confirmed smooth coating in polymeric tablets, spherical uniformity in nanoparticles, and a porous structure in hydrogels. In vitro dissolution studies revealed minimal drug release in gastric conditions (≤2% at pH 1.2) and sustained release at colonic pH (7.4). PLGA nanoparticles showed the most controlled release profile, achieving 92.1 ± 2.4% cumulative release at 24 hours, compared with 100.0 ± 3.1% for polymeric tablets and 85.4 ± 2.1% for hydrogels. Kinetic modeling indicated that all systems followed diffusion-dominated release, with nanoparticles best fitting the Higuchi model (R² = 0.981). Stability studies confirmed nanoparticle integrity under prolonged acidic and neutral exposure, while hydrogels exhibited partial deformation. Overall performance analysis identified PLGA nanoparticles as the most efficient system, demonstrating superior acid resistance, encapsulation efficiency, and colon-specific release. These findings suggest that nanoparticle-based carriers offer significant potential for achieving predictable, site-specific, and sustained drug delivery to the colon.

Poor water solubility is still a big problem in medication development since it typically makes oral formulations less bioavailable and less effective at treating diseases. The goal of this project was to create and test solid lipid nanoparticles (SLNs) as a new way to deliver medications that don't dissolve well. Four SLN formulations were made and tested using a hot homogenization followed by ultrasonication method. The tests looked at the size of the particles, the polydispersity index (PDI), the zeta potential, the entrapment efficiency, the drug loading, and the in vitro drug release. The results showed that higher concentrations of surfactants and lipids made the particles smaller, trapped more drugs, and released them over a longer period of time. Formulation F4 had the best performance, with a particle size of 130 nm, an entrapment efficiency of 88%, and a drug release rate of 85% at 24 hours. Statistical analysis showed that there were big differences across the formulations (p