The Preparation Of Methylene Blue Magnetic Gelatin Microspheres And Feasibility Of It's Application In Pain Management

Objective: To study preparation and characteristics of Methylene blue Magnetic Gelatin Microspheres (MMGMs) . Method: Methylene blue Magnetic Gelatin Microspheres are prepared by emulsion-crosslinking method, the microphere was observed by super-microscope and the diameter of microsphere was measured, the content of methylene blue is measured by method of ultraviolet spectrophotometer. Drug-releasing instrument was used to test the quantity of MB released from Methylene blue Magnetic Gelatin Microspheres and the magnetic responsibility was tested. Result: Methylene blue Magnetic Gelatin Microspheres were deep blue powder and their shape were globular and there were black magnetic particle in it when observation by the light microscope .The average diameter of the MMGMs were 38~50μm and when induced by magnetic field of 4000GS, their motion was irregular and move toward magnet, distance of thire motion was 70~80mm . There are 98μg methylene blue in lmg MMGMs so we calculate that the percent of drug containg are 9.8% and the ratio of drug envelopment are 34.3% . The percent of methylene blue released form MMGMs are 53% before 30 minutes, and then they are released gradually and the 90% of methylene blue are released at the 180 minutes during drug-releasing experiments in vitro. The best ratios of MB and carriers was 1:3 . So they have the shape and characteristics of magnetic drug microsphere . Conclusion: Methylene blue Magnetic Gelatin Microspheres is an new altered dosage form and preparing method was easy , hading good properties of drug-targeting and drug sustain releasing.Objective To study the feasibility of the spinal cord dorsal ganglia targeted nerve block in the subarachnoid space of rabbits uning Methylene blue Magnetic Gelatin Microspheres(MMGMs). Methods 24 rabbits were divided into 3 groups , 8 each group , Methylene blue Magnetic Gelatin Microspheres group(Mb), Magnetic Gelatin Microspheres group(M)and controlled group(C). Under the effect of magnetic field the rabbits of Mb group were injected MMGMs 15 mg and M group group were injected Gelatin Microspheres 15 mg in rabbits subarachnoid space , then the pain threshold of electronic stimulates and motor function of rabbits' hinder limbers and spinal cord evoked potentials were observed continuously after that., at last the pathological section of dorsal root ganglia and Cornu anterius medullae spinalis were made and studied. Results There was a significant difference for hinder limbers's pain threshold of electronic stimulates between Mb and others group(P<0.05)and between before and after injection(P<0.05), there was no significant difference for hinder limbers's motor function between Mb and others group(P>0.05) and between before and after injection(P>0.05). The latency period of Ni wave in SCEP was significantly extended at Mb group((P<0.05), others group didn't changed. The pathematology of DRG and CAMS in each groups were morphological normal. Conclusion MMGMs could be used in the spinal cord dorsal ganglia targeted nerve blocking in subarachnoid space under effect of magnetic field and the motor function was not destroyed .