title: Preparation of gelatin microbeads with a narrow size distribution using microchannel emulsification.
abstract: The purpose of this study was to prepare monodisperse gelatin microcapsules containing an active agent using microchannel (MC) emulsification, a novel technique for preparing water-in-oil (W/O) and oil-in-water (O/W) emulsions. As the first step in applying MC emulsification to the preparation of monodisperse gelatin microcapsules, simple gelatin microbeads were prepared using this technique. A W/O emulsion with a narrow size distribution containing gelatin in the aqueous phase was created as follows. First, the aqueous disperse phase was fed into the continuous phase through the MCs at 40 degrees C (operating pressure: 3.9 kPa). The emulsion droplets had an average particle diameter of 40.7 microm and a relative standard deviation of 5.1%. The temperature of the collected emulsion was reduced and maintained at 25 degrees C overnight. The gelatin microbeads had a smooth surface after overnight gelation; the average particle diameter was calculated to be 31.6 microm, and the relative standard deviation, 7.3%. The temperature was then lowered to 5 degrees C by rapid air cooling and finally dried. The gelatin beads were dried and could be resuspended well in iso-octane. They had an average particle diameter of 15.6 microm, and a relative standard deviation of 5.9%. Using MC emulsification, we were able to prepare gelatin microbeads with a narrow size distribution. Since this emulsification technique requires only a low-energy input, it may create desirable experimental conditions for microencapsulation of unstable substances such as peptides and proteins. This method is promising for making monodisperse microbeads.
authors.affiliation: Reaction & Separation Engineering Laboratory, National Food Research Institute, 2-1-12, Kannondai, Tsukuba, Ibaraki, 305-8642, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Iwamoto
authors.forename: Kei
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Shinji
authors.initials: S
authors.lastname: Sugiura
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Nakajima
mesh_terms: D002626:Chemistry, Pharmaceutical; D004337:Drug Carriers / Q000737:chemistry; D004339:Drug Compounding / Q000379:methods / Q000706:statistics & numerical data; D004655:Emulsions / Q000737:chemistry / Q000378:metabolism; D005780:Gelatin / Q000737:chemistry* / Q000378:metabolism*; D008863:Microspheres; D009795:Octanes / Q000737:chemistry; D010316:Particle Size; D013499:Surface Properties
chemical_list: D004337:Drug Carriers; D004655:Emulsions; D009795:Octanes; D005780:Gelatin; C045798:2,2,4-trimethylpentane