The mucous barrier is a major physiological obstacle that the mucosal drug delivery system needs to deal with. In response to this physiological barrier, many achievements have been made in research of mucosal adhesion and mucus penetration. This review puts emphasis on the progress of the research on new mucosal adhesion strategies such as cationization, sulfhydrylization, maleimide functionalization, lectinization and catechol conjugation; polyethylene glycol (PEG), polyvinyl alcohol (PVA), poly (2-alkyl-2-oxazoline) (POZ), zwitterionic polymers and other mucus-inert materials, strategies to enhance mucus penetration ability such as enzyme functionalization, reducing agent pretreatment and so on. The problems of each strategy are also analyzed and discussed, which can provide some references for clinical transformation.

The water-soluble polypeptide drug oxytocin was encapsulated in liposomes by reverse-phase evaporation vesicle method to obtain oxytocin loaded liposomes (OT@LPs) which was further modified with cationic cell penetrating peptide—arginine octamer (R8) to get R8 modified oxytocin loaded liposomes (OT@LPs-R8) which showed enhanced mucoadhesive. The brain targeting efficiency was evaluated preliminarily after nasal administration. OT@LPs-R8 showed a round shape with a particle size distribution of 110.2 ± 7.3 nm, a surface potential as high as +18 mV, a drug loading (62.17 ± 1.88) %, an encapsulation rate (5.85 ± 0.72) %, and stood stable in nasal mucus. After nasal administration, it could significantly prolong the retention and enhance the distribution in the brain with no irritation to the nasal mucosa. The animal experiment in line with the regulations of the Department of Laboratory Animal Science of Fudan University on the ethics of animal experiments had been carried out after passing the review of the Animal Ethics Committee of Fudan University. The results showed nasal administration of OT@LPs-R8 could promote oxytocin directly into the brain from the nose which expected to become a new carrier for delivery of oxytocin to the brain.

Objective: To investigate the relation between ser um hyaluronic acid (HA) concentration and cryopreservation-reperfusion injury. Methods: The animals were randomly assigned to 3 groups: (1 ) group A: the control; (2) group B: liver allografts were stored in lactated R inger's solution (0℃) for 2 h before implantation; (3) group C:liver allografts were stored in lactated Ringer's solution (0℃) for 4 h before implantation. Th e serum sample and liver specimen were taken up at 2 h and 4 h after transplanta tion to detect the concentration of HA, AST and LDH, and to get pathologic obser vation. Results: Serum HA increased earlier and decreased more s hortly than AST and LDH after transplantation in group A. Serum HA increased sig nificantly in group B and C, much higher than that in group A(P<0.01). The i njury of vascular endothelium and the disorder of hepatic sinuses and hepatic lo b ules were observed in group B and C. In the specimen of 4 h in group C, evident infiltration of inflammatory cell was present. Conclusion: Cryopreservation leads to injury of endothelial cell and reperfusion aggravat es this injury. The serum HA concentration indicates the degree of cold ischemia -reperfusion injury.