Preparationand Research Of α-Fe/Montmorillonite Magnetic Targeting Drug Controlled Release Carrier Material

Controlled release material is an important branch of biomedical materials. It plays animportant role in increasing the patient medication compliance and improving the effect ofclinical treatment, especially for the patients who take medicines for long-term, and hasprofound significance. α-Fe/montmorillonite magnetic material was successfully prepared bythe in-situ pillared-reduction method, followed by inverse suspension-cross linking method tooptimize the chitosan microspheres preparation technology, and α-Fe/montmorillonitecomposite material encapsulated in cross-linked chitosan microspheres, eventually acted as thecontrol release material which had magnetic targeting function. The composite material wascharacterized by X-ray diffraction (XRD), laser particle size analyzer, infrared spectroscopy(FT-IR), polarized light microscopy and scanning electron microscopy (SEM) and otherinstruments. The characterization by saturation magnetization, element content, specificsurface area, swelling ratio and encapsulation rate testing parameters of the magnetic materialsand drug loading properties focuses on further research and analysis. We discussed the releasecontrol mechanism in vitro of control release material on the model drug of bovine serumalbumin (BSA), and proposed two level control release model.The results showed that:(1) when0.1mol/L hydroxy-Fe was added as pillared agent,hydroxy iron ion and cation of the montmorillonite exchanged, leading to the interlayerspacing expanded to1.41nm and reached saturated pillared point. Montmorillonite interlayerhydroxyl iron was completely restored to α-Fe grains of116nm when the reluctant NaBH4was0.2mol/L and produced α-Fe/montmorillonite composite material. The average particle size ofthe composite was5.529μm, with the specific surface area reaching85.49m2/g, which was4.46times by that of the calcium-montmorillonite the content of Fe reached23.44%incomposite material, and the specific saturation magnetization was0.812emu/g (9×103A/m outside magnetic field)and exhibited ferromagnetism.(2) acetic acid, chitosan, glutaraldehyde(2vol.%,3g/L,1mL) were used as raw materials to prepare chitosan microspheres, and thenrestudied in well balling, uniform particle size distribution and the average particle size of58.94μm. FT-IR spectra showed that1637cm-1was Schiff base peak chart, and it explainedthe chitosan crosslinked with glutaraldehyde. When the ratio between chitosan and BSA was1:2, drug loading rate and entrapment rate of microspheres reached46.25%and41.25%,respectively. When the dosage of α-Fe/montmorillonite composite was10%, drug loading rateof magnetic microspheres was56.92%, with the encapsulation rate and the swelling rate of72.21%, and74.85%, respectively. Besides, the magnetic microspheres surface morphologyand dispersion properties were good.(4) Based on the analysis of the release experiments invitro and structure of magnetic microspheres, we proposed two level control release model thatα-Fe/montmorillonite composite with chitosan occurred double sustained release to drugs,which increased the release process of drug of magnetic loaded microspheres, and slow releaseshowed better.To sum up, magnetic controlled release material was prepared by a new synthetic method.The structures and properties of the composite material exhibited good constitutiverelationship and inner association. This research and application of the composite material inbiomedical field had an important scientific significance and application value.