title: Preparation of ethyl cellulose/methyl cellulose blends by supercritical antisolvent precipitation.
abstract: The supercritical antisolvent (SAS) technique was used to prepare ethyl cellulose/methyl cellulose blends, two biocompatible polymers commonly used as drug carriers in controlled delivery systems. Ethyl cellulose is widely used as a drug carrier. The drug release of the delivery devices can be controlled to some extent by addition of a water-soluble or water swellable polymer, such as methyl cellulose. This leads to the solubility enhancement of poorly water-soluble molecules. SAS experiments were carried out at different operational conditions and microspheres with mean diameters ranging from 5 to 30 microm were obtained. The effect of CO(2) and liquid flow, temperature and pressure on particle size and particle size distribution was evaluated. The microspheres were precipitated from a mixture of dichloromethane (DCM) and dimethylsulfoxide (DMSO) (4:1 ratio). The best process conditions for this mixture were according to our study 40 degrees C and 80 bar.
authors.affiliation: Nutraceuticals and Delivery Laboratory, ITQB/IBET, Aptd. 12, 2781-901 Oeiras, Portugal. rduarte@itqb.unl.pt
authors.forename: Ana Rita C
authors.initials: AR
authors.lastname: Duarte
authors.forename: M D
authors.initials: MD
authors.lastname: Gordillo
authors.forename: M Margarida
authors.initials: MM
authors.lastname: Cardoso
authors.forename: Ana Luísa
authors.initials: AL
authors.lastname: Simplício
authors.forename: Catarina M M
authors.initials: CM
authors.lastname: Duarte
mesh_terms: D002482:Cellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D011232:Chemical Precipitation; D025924:Chromatography, Supercritical Fluid; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D004337:Drug Carriers; D008747:Methylcellulose / Q000737:chemistry*; D008752:Methylene Chloride / Q000737:chemistry; D008863:Microspheres; D011108:Polymers / Q000138:chemical synthesis*; D011312:Pressure; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties; D013678:Technology, Pharmaceutical / Q000379:methods; D013696:Temperature
chemical_list: D004337:Drug Carriers; D011108:Polymers; D012997:Solvents; D008752:Methylene Chloride; C013517:ethyl cellulose; D002482:Cellulose; D008747:Methylcellulose; D004121:Dimethyl Sulfoxide