Production And Pharmacokinetic Research Of NGF-liposome

ObjectiveTo pack nerve growth factor with liposome and to study its pharmacokinetic parameters.MethodsIn first part, NGF-liposome was produced. Tissue of mice's submaxillary glands was centrifuged and separated in CM52 column, thus 2.5S NGF was produced. Electrophoresis was used to measure the purity and Bradford way to detect the content. To identify activity of NGF, cultivating DPG of chick embryo was performed. NGF was packed with liposome to produce NGF-liposome and correlative parameters were detected.In second part, pharmacokinetics of NGF-liposome in vivo was studied. NGF was labeled with 99mTc and isotopic tracing was utilized to detect concentration of NGF in rabbit blood. Compared with packed group, unpacked NGF group were detected. Data were inputted into computer to be analyzed of pharmacokinetic parameters, compartment model etc. by software (3p97). From SPECT distribution of lipo-99mTc-NGF in rabbit body was shown as well 99mTc-NGF to be compared with. Urine and dejecta was collected for the analysis of excretion in rabbit body. ELISA was the method to detect concentration of NGF in CSF and TCA method was used to detect radioactivity of deposit of urine.ResultsIn first part, it was indicated that the abstracted protein was NGF of which the content was ling/ml and biologic activity was fine. NGF was packed with liposome and NGF-liposome was produced.In second part, we have found that the relationship of concentration of NGF and count of -ray was nearly linear. From the test of recovery and precision, it was suggested that labeling NGF with 99mTc to detect concentration of NGF was feasible. Pharmacokinetic parameters of NGF packed with liposome injected in vivo in rabbit body were: t1/2=0.2338h, t1/2=1.3229h, AUC=106.57(ng/ml)*h. Parameters of unpacked NGF were: t1/2 =0.077h, t1/2 =0.88h,AUC=98.656(ng/ml)*h. It was shown in pictures of SPECT, if NGF was packed with liposome there was NGF distributing in brain. Analysis of urine and dejecta indicated that main excretion route of unpacked NGF was urine and that of NGF packed with liposome was urine as well bile. Detection of NGF in CSF pointed that if NGF was packed peak of concentration in CSF was at 2hours whereas if NGF was unpacked NGF was undetectable. From SPECT, it was shown that there was radiological concentration in brain if 99mTc-NGF was packed with liposome. Radioactivity of urine deposit was undetectable in TCA method.ConclusionWhen NGF is packed with liposome, absorption, distribution, metabolism and excretion of NGF will change. T1/2 and T1/2p are prolonged and NGF can pass BBB.