Hydrophobically-modified Chitosan Microspheres for Release of Diosgenin
Sprache des Titels:
Englisch
Original Kurzfassung:
Chitosan microspheres (CS) prepared by water-in-oil
emulsion/glutaraldehyde cross-linking-evaporation and simple
coacervation/cross-linking with sodium tripolyphosphate were
covalently linked to diosgenin hemiesters. The diosgenin content
found using elemental analysis was ca. 6 to 42 wt-% and it
showed dependence on the type of diosgenin hemiesters and
on the method of preparation of the CS microspheres. Fourier
transform infrared spectroscopy confirmed the hydrophobic
functionalization of CS with the diosgenin hemiesters by amide
bond formation. The effect of CS modification with diosgenin
on the thermal properties was also studied using differential
scanning calorimetry. Microsphere sizes determined using
optical microscopy ranged from 60 to 700 um, while scanning
electron microscopy depicted morphology dependent on the
selected method to obtain CS microspheres. In vitro release
studies performed in aqueous medium indicated a drug release
dependence on the diosgenin hemiester linkers, the steroid
content and the acidity of the solution. Sustained diosgenin
release in acidic aqueous solution (pH 6.0) reached from 34 to
81% after 48 h.