Sustained-release of protein from biodegradable sericin film, gel and sponge

• Published in: International journal of pharmaceutics Vol. 407; no. 1; pp. 44 - 52
• Main Authors: Nishida, Ayumu, Yamada, Masaki, Kanazawa, Takanori, Takashima, Yuuki, Ouchi, Kiyohisa, Okada, Hiroaki
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 04.04.2011; Elsevier
• Subjects: Amino acids; Animals; Biodegradability; Biodegradable; Biodegradation; Biological and medical sciences; Biomaterials; Controlled release; Delayed-Action Preparations; drug formulations; Drug Implants; Excipients - chemistry; fluorescein; Fluorescein-5-isothiocyanate - administration & dosage; Fluorescein-5-isothiocyanate - analogs & derivatives; Gel; Gels; General pharmacology; Hydrophobic and Hydrophilic Interactions; Hydrophobicity; Inflammation; Male; Medical sciences; Molecular Weight; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; polypeptides; Rats; Rats, Sprague-Dawley; Sericin; Sericins - chemistry; Serum Albumin - administration & dosage; Silk; Sponge; Sustained release; Time Factors; Sericin; Sustained release; Sponge; Biodegradable; Film; Gel; Pharmaceutical technology; Biodegradability; Controlled release form; Animal origin; Colloidal gel; Marine environment; Porifera; Dosage form; Animal protein; Invertebrata
• ISSN: 0378-5173; 1873-3476
• DOI: 10.1016/j.ijpharm.2011.01.006

The film, gel and sponge forms of silk protein, sericin, were examined to determine the characteristics of sustained release of a drug protein model and the biodegradability. A silk protein, sericin, contains 18 kinds of amino acids, mostly polar side chains forming a complex of three principal polypeptides. The major polypeptides exhibit hydrophobic characteristics by forming a β-sheet structure in a hydrate state. As a drug-releasing biomaterial made by an aqueous process without using any cross linker, sericin is expected to form various hydrophobic dosage forms. However, its dosage form, with respect to the molecular weight and concentration of sericin, and its biodegradation behavior has not been studied in detail. In this study, the film, gel and sponge of sericin were prepared and examined to determine the release properties of the charged protein, fluorescein isothiocyanate–albumin (FA). The film and gel, as solid and semisolid forms, respectively, were also evaluated for their biodegradation behavior. For in vitro release, FA was sustained-released from these preparations. The concentration and dosage form markedly affected FA release. For in vivo biodegradation, the sericin preparations implanted subcutaneously in rats gradually decreased in size and weight. Histological examination indicated no marked inflammation at the site. As for in vivo release, FA remained for 3–6 weeks or more in rats. These findings suggest that sericin is suitable for use as a drug-releasing biomaterial.