Aim: The relative bioavailabilities and effects on lung injury alleviation of 4 insu-lin-artificial pulmonary surfactant (INS-APS) preparations were studied in normal rats. The relationship between the minimal surface tension (γmin) of INS-APS and the absorption of insulin was also investigated. Methods: Four formulations of APS [1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)/lecithin/palmitic acid (PA), DPPC/1-hexadecanol (Hex)/tyloxapol (Tyl), DPPC/L-α-phosphatidyl-DL-glyc-erol sodium salt (PG), DPPC/Tyl] were prepared by thin-film sonication method and direct sonication. The γmin of 4 APS dispersions was examined with and without INS by pulsating with a bubble surface tensiometer. In vivo experiments were performed in which serum glucose change and the insulin level were mea-sured by an enzymatic glucose reagent kit and a radioimmunology assay kit after IT to rats. The reduction in lung injury by INS-APS following 7 d of consecutive administration was evaluated by the pulmonary edema index (the weight ratio of wet lung to dry lung) and histopathology examination. Results: The γmin of all APS dispersions were below 10 mN/m. There was no significant difference (P>0.05) between the γmin of APS and the corresponding INS-APS. In vivo experi-ments showed a significant glucose level decrease and insulin absorption increase (P<0.05) in the presence of APS, compared to the insulin solution alone.From the results, we found that the pulmonary edema index values of all the INS-APS groups were significant lower (P0.05) between INS/DPPC/Tyl, INS/DPPC/PG, and the control group. The pulmonary edema indices and histopatho-logical observation indicated that INS-APS could alleviate lung injury. Conclusion:The most potent hypoglycemic effect and insulin absorption increase in this study were obtained with INS/DPPC/Tyl. According to the results, there was a linear correlation between the γmin and relative bioavailability of INS-APS, suggesting a possible effect of the γmin of carders on the in vivo absorption of insulin. APS,DPPC/Tyl, and DPPC/PG dispersions might be the most efficient insulin pulmo-nary delivery carders in achieving a lower γmin enhancing insulin absorption, and decreasing lung injury.