Chitosan/Carboxymethyl Cellulose Nanocomposites Prepared via Electrolyte Gelation–Spray Drying for Controlled Ampicillin Delivery and Enhanced Antibacterial Activity

This study reports the fabrication of chitosan/carboxymethyl cellulose (C/M) nanocomposites by electrolyte gelation–spray drying and the evaluation of their antibacterial performance as carriers for the antibiotic ampicillin. Chitosan (C), a cationic biopolymer derived from chitin, was combined with the anionic polysaccharide carboxymethyl cellulose (M) at different mass ratios to form stable nanocomposites via electrostatic interactions and then collected in a spray dryer. The resulting particles exhibited mean diameters ranging from 800 to 1500 nm and zeta potentials varying from +90 to −40 mV, depending on the C/M ratio. The optimal formulation (C/M = 2:1 ratio) achieved a high recovery yield (71.1%), lower PDI (0.52), and ampicillin encapsulation efficiency EE (82.4%). Fourier transform infrared spectroscopy (FTIR) confirmed the presence of hydrogen bonding and ionic interactions among C/M, and ampicillin within the nanocomposite matrix. The nanocomposites demonstrated controlled ampicillin release and pronounced antibacterial activity against Staphylococcus aureus, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 3.2 µg/mL and 5.3 µg/mL, respectively, which were lower than those of free ampicillin. These results indicate that the chitosan/carboxymethyl cellulose nanocomposites are promising, eco-friendly carriers for antibiotic delivery and antibacterial applications.