Genipin-crosslinked carboxymethyl chitosan nanogel for lung-targeted delivery of isoniazid and rifampin

Lung-targeted genipin-crosslinked deacetylated chitosan (GEN-CS)/isoniazid (INH)/rifampin (RMP) nanogel particles (NGPs) were prepared as a treatment for tuberculosis caused by multidrug-resistant Mycobacterium tuberculosis (MTB) to surmount the undesirable side effects and decrease the cytotoxicity of INH and RMP when being against MTB. The size, morphology, in vitro release property, long-term antibacterial performance, stability, in vitro cytotoxicity, in vivo toxicity, and in vivo release property of GEN-CS/INH/RMP NGPs inhalation powder were investigated. The results showed that the GEN-CS/INH/RMP NGPs inhalation powder exhibited extended antibacterial activity because of its long-term release of INH and RMP. A simplex GEN-CS/INH/RMP NGPs pulmonary dose led to the therapeutic drug concentration of 40%-60% in lung and other organs (＜5%) for 24 h. Furthermore, this GEN-CS/INH/RMP NGPs lyophilized inhalation powder displayed lung-targeted property and lower in vivo toxicity. These results suggested that this GEN-CS/INH/RMP NGPs inhalation powder would be a more useful dosage form than separate dose of INH or RMP for MTB.