The principal objective of the present study is to achieve a depot formulation of Risperidone by gelation of silk fibroin (SF). For this purpose, hydrochloric acid (HCl)/acetone based and methanol based hydrogels were prepared with different drug/polymer ratios (1:3, 1:6 and 1:15). For all the drug-loaded methanol based hydrogels, gel transition of SF solutions occurred immediately and gelation time was 1 min, while the gelation time of HCL/acetone based hydrogels was around 360 min. From Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) spectra, solvent systems, and Risperidone could induce β–sheet structure, but HCL/acetone system had the lowest effect on induction of β–sheets. The crystallinity was increased by increasing the amount of Risperidone, and drug to polymer ratio of 1:3 possessed the highest crystallinity. Thermogravimetric analysis (TGA) indicated that increasing the amount of drug in formulation increased the stability of hydrogels, and methanol based hydrogel with a ratio of 1:3 had the most stable structure. The release rate of Risperidone from methanol based hydrogel at ratio of 1:3 was lower than that for HCl/acetone based one, and it decreased by increasing amount of Risperidone. The release of Risperidone from methanol hydrogel at ratios 1:3 and 1:6 continued up to 25 days which is acceptable for depot form of Risperidone and shows that the extended release of Risperidone was achieved successfully. In conclusion, SF hydrogel with the ability to respondto the environmental stimuli is an excellent candidate for injectable implants for extended release of Risperidone.
کلید واژگان :Silk fibroin; Risperidone; Hydrogel; Gelation time; Injectable implant; Sustained release
ارزش ریالی : 600000 ریال
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