ABSTRACT
Objective Enzyme triggered multi unit colon targeting mini tablet of indomethacin were prepared,in order to improve the target treatment of colon disease.Methods Different proportion of enteric layer and chitosan layer were screened to optimize the prescription.The colon targeting mini tablets were prepared by direct compression method.The drug release properties were investigated in different release medium.Rats were used to investigate the distribution of tissue in vivo.The Beagle dogs were used to study the pharmacokinetics and bioavailability.Results The optimum chitosan layer prescription:coating liquid concentration was 2％,plasticizer three citric acid ethyl ester (TEC) was 15％,an anti sticking agent amount of talc was 30％,coating weight was 5％;Enteric layer prescription:coating liquid solid content was 20％,plasticizer content of TEC was 5％,anti sticking agent talc powder dosage was 40％,coating weight was 3％.The chitosan multi unit colon targeted preparation seldom released in rat stomach and small intestine,released slowly in colon.The pharmacokinetics parameters in Beagle dogs were:Cmax =(3.25 + 0.672) mg·L-1,tmax =(2.00 + 0.014) h,AUC(0.∞) =(10.2 +0.871) mg·L-1 ·h,MRT (0-∞) =(2.82 + 0.180) h,CL =(2.46 + 0.202) L·h-1 ·kg-1.The release time of mini tablets for colon targeted was significantly prolonged and preserved stable blood concentration.Conclusion The enzyme triggered multi unit colon targeting mini tablet of indomethacin showed good target to colon and sustained release effect,providing an important reference for the development of preparation of indomethacin for the treatment of colon disease.
ABSTRACT
Objective To explore the activity of heme oxygenase and immunolocate the enzyme in the adult worms of Schistosoma japonicum .Methods Microsomal protein was isolated from the homogenate of adult S^japonicum , heme degradation and effect of different pH conditions and buffers on degrading reaction were investigated by incubating microsomal protein with hemin. The slices of whole worm and cells of S^japonicum were prepared, distribution of HO in schistosome was studied by immunofluorescent and alkaline phosphatase(AP) \|immunocytochemical assays.Results Microsomal protein of adult worms can degrade the heme in vitro , the activity being 56^7 nmol bilirubin/(mg?min).The optimal pH was 8^7. Immunofluorescent and AP\|immunocytochemical assays revealed that the HO distributed dispersively in the worm, and located in cytoplasm.Conclusion The presence of HO was firstly proved in S^japonicum .