title: The characterization of protein release from sericin film in the presence of an enzyme: towards fibroblast growth factor-2 delivery.
abstract: Aqueous preparations of silk protein (sericin) films were prepared to evaluate their biodegradation properties. In the absence of trypsin, sericin film swelled rapidly, kept its shape, and remained unaltered for 28 days or longer due to form β-sheet structures. In the presence of trypsin, sericin film gradually degraded; since the rate depended on the concentration of trypsin, the films likely underwent enzymatic hydrolysis. Sericin film incorporating the model protein drug fluorescein isothiocyanate-albumin (FA) also gradually degraded in the presence of trypsin and resulted in the sustained release of FA for 2 weeks or longer; in contrast, FA release was quite slow in the absence of trypsin. It is expected that sericin film has potential as a biodegradable and drug-releasing carrier. To evaluate the practical applicability of sericin film for the repair of defective tissues, fibroblast growth factor-2 (FGF-2) was incorporated into sericin films and the films were implanted on skull defects in rats. Whereas FGF-2 release was suppressed in the absence of trypsin in vitro, it appears that FGF-2, immobilized by ionic interactions between sericin and FGF-2, can be sustained-released in vivo from films incorporating 2500 or 250 ng of FGF-2 to support the growth of tissue around wounds.
authors.affiliation: Pharmaceutical Technology Laboratories, Kissei Pharmaceutical Co, Ltd, 4365-1 Kashiwabara, Hotaka, Azumino 399-8304, Japan. ayumu nishida@pharm.kissei.co.jp
authors.forename: Ayumu
authors.initials: A
authors.lastname: Nishida
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Naganuma
authors.forename: Takanori
authors.initials: T
authors.lastname: Kanazawa
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Takashima
authors.forename: Masaki
authors.initials: M
authors.lastname: Yamada
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Okada
mesh_terms: D000818:Animals; D001685:Biological Factors / Q000032:analysis / Q000737:chemistry / Q000378:metabolism / Q000627:therapeutic use; D001688:Biological Products / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism / Q000627:therapeutic use; D012831:Bombyx; D004337:Drug Carriers; D004339:Drug Compounding; D016503:Drug Delivery Systems; D016222:Fibroblast Growth Factor 2 / Q000008:administration & dosage / Q000032:analysis / Q000737:chemistry* / Q000627:therapeutic use; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives / Q000032:analysis; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D047030:Sericins / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism / Q000627:therapeutic use; D012887:Skull Fractures / Q000628:therapy; D014357:Trypsin / Q000378:metabolism; D014945:Wound Healing / Q000502:physiology
chemical_list: D001685:Biological Factors; D001688:Biological Products; D004337:Drug Carriers; D047030:Sericins; D016222:Fibroblast Growth Factor 2; D014357:Trypsin; D016650:Fluorescein-5-isothiocyanate