Background/Objectives: Tuberculosis treatment remains challenging due to the limited stability and side effects of conventional rifampicin formulations. This study aimed to synthesize and optimize mucoadhesive chitosan–gellan gum nanoparticles for improved rifampicin delivery. The novelty of this work was the introduction of ethanol into the synthesis process, which improved the solubility of rifampicin and contributed to the formation of nanoparticles with the desired physicochemical characteristics. Methods: Rifampicin-loaded chitosan–gellan gum nanoparticles were produced using the polyelectrolyte complex coacervation method. The polymer ratios, drug-to-polymer ratio, temperature and ethanol volume were the main factors that were optimized using the Taguchi method. The physicochemical properties, such as TGA, DSC and FTIR spectroscopy, were investigated. In addition, drug release, mucoadhesive properties and mycobacterial activity against the H37Rv strain of Mycobacterium tuberculosis were examined. Results: Optimization using the Taguchi method produced nanoparticles with a narrow particle distribution (PDI: 0.212 ± 0.021), a satisfactory average size (153 ± 3 nm) and stability against aggregation (zeta potential: 22.94 ± 1.30 mV). A study of the degree of rifampicin release from nanoparticles showed that the drug release is influenced by pH and has a prolonged effect. Drug-loaded nanoparticles exhibited increased mucoadhesion compared with the pure drug. The minimum inhibitory concentration of rifampicin in chitosan–gellan gum nanoparticles for the suppression of the H37RV strain of Mycobacterium tuberculosis was determined. Spectroscopic and thermal analyses confirmed the incorporation of rifampicin in the polymer matrix. Conclusions: The developed chitosan–gellan gum nanoparticles represent a promising mucoadhesive delivery system for rifampicin. The incorporation of ethanol and the use of Taguchi optimization provide an effective strategy for controlling nanoparticle properties and improving drug delivery performance.

Pulmonary delivery of anti-tuberculosis drugs has emerged as a promising alternative for increasing local drug concentrations whilst minimising side effects. Natural polymers—polysaccharides capable of forming polyelectrolyte complexes (PECs) through electrostatic interactions—show great promise in this field. In this study, mucoadhesive chitosan-gellan gum nanoparticles were developed for the controlled release of isoniazid using the polyelectrolyte complex coacervation method. Parameters such as the chitosan-to-gellan gum ratio and the medium pH were investigated to achieve suitable particle size, polydispersity, surface charge, drug loading and encapsulation efficiency. The morphology of the produced nanoparticles was determined using transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA), which confirmed the formation of nanoscale spherical particles. The mucoadhesive properties were tested on ovine lung tissue using fluorescence retention analysis, whilst in vitro drug release was studied under physiological conditions. Antimycobacterial activity against Mycobacterium tuberculosis H37Rv was assessed using the Mycobacteria Growth Indicator Tube (MGIT) system, followed by subculturing on Löwenstein–Jensen medium. The produced nanoparticles exhibited high mucoadhesion, maintaining prolonged retention on lung tissue. Drug release showed an initial burst followed by sustained release over 24 h. These results demonstrate that CSGG–INH nanoparticles possess sustained drug release, good mucoadhesion to the lungs and high antimycobacterial activity, supporting their further development as potential carriers for pulmonary delivery of anti-tuberculosis drugs.