Effect of RMP-7 and its derivatives on the transportation of liposome into the brain

To study the action of RMP-7 and its derivative on transporting liposome across the blood brain barrier (BBB) into the brain. RMP-7 and DSPE-PEG-NHS [[1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-n-[poly (ethylene-glycol)]-hydroxy succinamide]] were conjugated together in mild condition and MALDI-TOF-MS (Matrix-Assisted Laser Desorption-Ionization Time-of-Flight Mass Spectrometry) was used to determine their molecular ratio. An in vitro BBB model was established and used to determine in vitro bioactivity of RMP-7 and its derivative. The fluorescence of brain slices and the Evens Blue (EB) concentration in the brain, liver, spleen, lung and kidney of each group were used to evaluate the in vivo bioactivity of RMP-7 and its derivative on transporting liposome across the BBB. The average molecular weight (MW) of the reaction product was 4,900, while those of DSPE-PEG-NHS and RMP-7 were 3,224 and 1,098. The results demonstrated that RMP-7 was conjugated to DSPE-PEG-NHS at the molecular ratio of 1:1, so the produ