Application of chitosan microspheres as carriers of LH-RH analogue TX46

Two kinds of swellable chitosan microspheres were prepared by cross-linking technique and dry-in-oil method in this study. The properties of these microspheres including morphology, the water content, the ion exchange capacity and FTIR of the microspheres were investigated. The polypeptide drug Luteinizing hormone-releasing hormone (LH-RH) analogue (TX46 as a model drug) was loaded in the microspheres and released in vitro. The effects of diameter, cross-linking degree of the microspheres and the deacetylated degree of chitosan on the adsorption capacity and release behavior were studied. A novel kind of chitosan microspheres, which contained glycine were also prepared and employed to adsorb and release TX46. The maximum adsorption capacities of dry-in-oil microspheres, cross-linking chitosan microspheres and the chitosan-glycine microspheres for TX46 were 11.1, 44.6, 61.2 mg TX46/g, respectively. The results showed that the addition of glycine could greatly improve the adsorption capacity and sustain the release rate of TX46.