Modifications of Ganoderma lucidum spores into digestive-tissue highly adherent porous carriers with selective affinity to hydrophilic or hydrophobic drugs

Ganoderma lucidum spores (GLSs) have been suggested to provide optimal structures for transporting orally bioavailable drugs. However, the double-layer wall and cavities of GLSs are naturally closed. This study aimed to modify GLSs into porous carriers by opening the layers and internal cavity with iturin A (IA) followed by potassium hydroxide (KOH) or hydrochloric acid (HCl). The (IA + KOH)- and (IA + HCl)-treated GLS carriers exhibited a high loading rate of 301.50 ± 2.33 and 268.18 ± 7.72 mg/g for the hydrophilic methylene blue (MB) and hydrophobic rifampicin (RF), respectively. The mechanisms underlying the modification involved the enhancement of the specific surface area with IA and the exposure of hydrophilic groups or hydrophobic groups of the GLSs with KOH or HCl. The sustained 48-h molecule-release profiles of the MB- and RF-loaded GLS carriers were best fitted using a first-order kinetics model in simulated gastric (or intestinal) fluid compared with other models. In mice, the designed GLS carriers had high adhesion capacities onto the mucosa of the digestive tract and long retention times (120 h), and even promoted the secretion of mucus and expression of several key intestinal barrier proteins. This study provided a new method to modify GLSs into oral carriers with selective drug affinity, high loading capacity, sustained drug release, and high adhesion to the digestive tract.