Preparation of Methotrexate Sustained-Release Microspheres / 中国药学杂志

ABSTRACT

OBJECTIVE: To prepare a novel methotrexate sustained-release microspheres system, and study its in vitro release properties. METHODS: The CS-montmorillonite (CS-MMT) intercalative composites were prepared by using chitosan and montmorillonite. The novel drug sustained-release system was prepared with CS-MMT as the carrier material and methotrexate as the model drug. The microspheres were characterized by Fourier transform infrared spectrometer (FTIR), electric microscope, UV-spectrophotometer (UV), as well as Malvernlaser particle size analyzer. The influences of the amount of composite materials, dosage of emulsifiers, ratio of oil/water and dosage of crosslinking agent on the drug loading and entrapment rate of microspheres were investigated. And in vitro release experiment was used to study the drug release properties of the microspheres. RESULTS: The shape and size of the microspheres were uniform. The drug loading, average particle size and Zeta potential were 31.6%, 557.4 nm and 20.8 mV respectively under the optimal conditions, ie, ratio of water/oil of 1∶5, amount of glutaraldehyde(aqueous phase)of 6%, dosage of emulsifiers (oil phase) of 7%, CS-MMT/CS ratio of 1∶4, and MTX/CS ratio of 1∶3. Methotrexate sustained-release system was pH-sensitive and tended to show a larger release percentage in hydrochloric acid solution. CONCLUSION: CS-MMT can be used as a slow-release excipient. CS-MMT microspheres are good controlled-release carrier for drugs, with pH sensitivity.