rmp-7 and 1-2-distearoylphosphatidylethanolamine

To improve transporting drugs across the Blood Brain Barrier (BBB) into the brain, RMP-7 was conjugated to the surface of liposomes containing Amphotericin B (AmB) for cerebral inflammation, because it can selectively bound to the B2 receptors on the capillary blood vessel. First, RMP-7 was conjugated to DSPE-PEG-NHS [1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-n-[poly (ethylenegly-col)]-hydroxy succinamide, PEG M 3400] under mild condition to obtain a predominantly 1:1 conjugate (DSPE-PEG-RMP-7), as evidenced by the Matrix-Assisted Laser Desorption-Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS). The second, endothelium cell was cultured on the cell insert to form an in vitro BBB model and the stereoscan microscope, electric resistance and permeation of horse-radish peroxidase (HRP) across the endothelium cell monolayer were used as indicators to evaluate the integrality of the monolayer, and then the in vitro BBB model was used to determine the bioactivity of DSPE-PEG-RMP-7 "opening" BBB. The results demonstrated the in vitro BBB model was set up, RMP-7 and DSPE-PEG-RMP-7 could improve the transporting of HRP across the BBB. The third, the liposomes containing AmB (AmB-L-PEG) was prepared by modified Film-sonication method and DSPE-PEG-RMP-7 was used to modify the AmB-L-PEG to obtain AmB-L-PEG-RMP-7. The fourth, tissue distribution of AmB in the rats of three groups was determined: Group I, AmB-L-PEG; Group II, AmB-L-PEG+RMP-7 (the physical mixture of AmB-L-PEG and RMP-7); Group III, AmB-PEG-RMP-7. The drugs were transfused into the rats through the femoral vein. The concentration of AmB in the tissue was checked using High-Performance Liquid Chromatography (HPLC) method. The rank of AmB concentration in the brain were as follows: III>II>I. The AmB concentration in the liver, spleen, lung and kidney had no significant difference. The concentration of AmB in the brain of the group III was raised several times higher than that in the other two groups, because the DSPE-PEG-RMP-7 had been inserted in the surface of AmB-L-PEG. Both the RMP-7 and AmB-L-PEG could reach BBB at the same time. When RMP-7 selectively reacted with the B2 receptor, the BBB is "opened" and AmB was transported into the brain at the same time. While in group II, the RMP-7 could improve the AmB concentration in the brain a little, because the RMP-7 and liposomes could not reach BBB at the same time. The distribution of AmB in the tissues demonstrated that the RMP-7 and its

Topics: Aminoglycosides; Amphotericin B; Animals; Anti-Bacterial Agents; Biological Transport; Blood-Brain Barrier; Bradykinin; Cell Membrane Permeability; Chromatography, High Pressure Liquid; In Vitro Techniques; Injections, Intravenous; Liposomes; Particle Size; Phosphatidylethanolamines; Polyethylene Glycols; Rats; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Tissue Distribution

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 product was DSPE-PEG-RMP-7. RMP-7 and DSPE-PEG-RMP-7 was shown to improve the transporting of peralcohol enzyme across the in vitro BBB model 2-3 times higher than the peralcohol enzyme only. DSPE-PEG-RMP-7 could facilitate the transporting of EB into brain more easily than RMP-7.. Both RMP-7 and DSPE-PEG-RMP-7 could facilitate the transporting of liposome across the BBB, especially DSPE-PEG-RMP-7.

Topics: Animals; Biological Transport; Blood-Brain Barrier; Bradykinin; Brain; Drug Carriers; Drug Delivery Systems; Evans Blue; Liposomes; Phosphatidylethanolamines; Polyethylene Glycols; Rats; Rats, Sprague-Dawley; Tissue Distribution