The Labeling Of RhG-CSF With ～(125)I And The Study Of The Absorption Of RhG-CSF In The Lung Of Rat

ObjectiveRhG - CSF was labeled with 125I by the method of lodogen and 125I - rhG -CSF came out. Then I examined the absorption of it by lung and the change of number of WBC, which proved an effective route for clinical use.MethodMaking 125I-rhG-CSF:Add PBS (0.05mol/L,PH=7.6) 50ul, plain rhG-CSF (75ug/100ul) 100ul and Na 125I solution 10ul(37MBq) by order, and react in the condition of room temperature for 15 minute. Surge the mixture for 30 second temperately every 3 minute in the course of reaction, add PBS (PH7. 6) 40ul when the reaction is over and put it quietly in the condition of room temperature for 5 ~ 10 minute continually.Administration of drug and collection of blood samples:In the group of absorption with intratracheal administration, administrate 125I - rhG - CSF by the dose of 5ug/kg. Blood samples were collected before and 5, 10, 15, 20, 30, 60, 90, 120, 240, 360, 480 after the administration of 125I -rhG - CSF. In the intravenous administration group, 125I - rhG - CSF was given by the dose of 5ug/kg. Blood samples were collected 5, 10, 15, 20, 30, 60, 90, 120, 240, 360, 480 minute after administration. Then examine the radioactivity of the samples. In the WBC counting group, rhG - CSF was administrated intratracheal by the dose of 10ug/kg, 50ug/kg, 100ug/kg and 200ug/ kg. Blood samples were collected before and 8, 16, 24, 32, 40, 48, 56, 64, 72 hours after administration. And take count of the WBC. In the other WBCcounting group whose objective is to compare the effect among the intratracheal administration, intravenous administration and subcutaneous administration, rhG -CSF was given by the dose of 200ug/kg. In the group of comparison, saline solution was administered intratracheally. And the sample collection and counting of WBC are as the up.ResultRadiochemical purity, percent of dissociative iodine and ratio of associative iodine of labeled compound: Radiochemical purity is 97. 8% , Rf = 0; percent of dissociative iodine <5% , and is far from origin, Rf = 0. 3 ~0. 6 and Rf = 0.4 -0.7. The radio of associative iodine is 78.4% , and the specific activity is 86. 34TBq/mmol. The radiochemical purity of labeled compound is still more than 90% after being put in 4C for 40 days.Absorption experiment:The concentrations of rhG - CSF in the group of intratracheal administration and intravenous administration and the corresponding times were processed by program 3p97. And the relative bioavailability of intratracheal administration to intravenous administration was 15.7%.WBC counting experiment:The pharmacological effect appeared more slowly and the peak number was more of intratracheal administration than intravenous administration. In the group of 10ug/kg, the peak number was reached in 24 hours but in the group of 50 ~200ug/kg, the peak number was reached in 40 hours.Conclusion1. The method of lodogen being used to label rhG - CSF with 125I is convenient, effective and steady.2. Intratracheal administration is an effective route to use.