Synthesis and optimization of gemcitabine-loaded nanoparticles by using Box–Behnken design for treating prostate cancer: <i>In vitro</i> characterization and <i>in vivo</i> pharmacokinetic study

Abstract Gemcitabine (GC)-loaded chitosan nanoparticles were synthesized by ionic gelation method, and optimization was accomplished by Box–Behnken design based on particle size (PS), polydispersity index (PDI), zeta potential (ZP), and percent entrapment efficiency (% EE). The optimized formulation (OF) exhibited PS, PDI, ZP, and % EE to be 206.7 nm, 0.285, +27 mV, and 77.61%, respectively. Fourier transform infrared spectroscopy, X-ray diffraction analysis, and differential scanning calorimetry analyses confirmed GC’s stability in nanoparticles. The OF showed an initial rapid release of 61%, followed by a slower release, reaching 95.81% over 96 h. OF was studied on a PC-3 cell line to evaluate its effectiveness in treating prostate cancer, where it exhibited higher cytotoxicity (IC 50 ∼3.06 ± 0.32 μg/ml) compared to pure GC (IC 50 ∼4.11 ± 0.81 μg/ml). After oral administration in albino rabbits, the peak plasma concentrations ( C max ) for GC solution and OF were 1,290 and 3,070 ng/ml, respectively. The time to reach maximum plasma concentration ( t max ) was 1 h for GC solution and 6 h for OF. The half-life ( t 1/2 ) was 5.6 h for GC solution and 16.9 h for OF, indicating a prolonged half-life for OF. OF demonstrated an effective release pattern of GC, improved stability, enhanced pharmacokinetic profile, and higher toxicity compared to GC.