Porous microcapsule formation with microsieve emulsification.
A simple route is presented to prepare core-shell Eudragit microcapsules through a solvent extraction method with the use of microsieve emulsification. Droplets from a solution of Eudragit FS 30D (a commercial copolymer of poly(methyl acrylate-co-methyl methacrylate-co-methacrylic acid) 7:3:1) and hexadecane in dichloromethane are dispersed into water, using a micro-engineered membrane with well-defined pores, in a cross-flow setting. The dichloromethane is extracted from the droplets, which induces demixing in the droplets, leading to a hexadecane-rich core, and an Eudragit-rich shell. The obtained microcapsules have a narrow size distribution due to the microsieve emulsification process. The capsules have a porous shell as shown by SEM and AFM measurements. Their porosity and pore size is dependent on the ratios of Eudragit and hexadecane in the dispersed phase. At pH 7.1 and above Eudragit (FS 30D) dissolves in water; this pH change is used to release the contents of the microcapsule.
Laboratory of Organic Chemistry, Wageningen University, 6703 HB Wageningen, The Netherlands. nagesh.wagdare@wur.nl
Nagesh A
NA
Wagdare
Antonius T M
AT
Marcelis
Remko M
RM
Boom
Cees J M
CJ
van Rijn
D000473:Alkanes / Q000737:chemistry; D002214:Capsules / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry; D004339:Drug Compounding / Q000379:methods*; D045703:Emulsifying Agents / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008752:Methylene Chloride / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D011108:Polymers / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D016062:Porosity; D014867:Water / Q000737:chemistry
D000473:Alkanes; D002214:Capsules; D004337:Drug Carriers; D045703:Emulsifying Agents; D011108:Polymers; D011109:Polymethacrylic Acids; D014867:Water; C038300:methylmethacrylate-methacrylic acid copolymer; D008752:Methylene Chloride; C007932:n-hexadecane