title: Cellulose acetate butyrate microcapsules containing dextran ion-exchange resins as self-propelled drug release system.
abstract: Sulfopropylated dextran microspheres (SP-Ms), (Dm = 80 microm) loaded with a water soluble drug (Tetracycline HCl), were included in cellulose acetate butyrate (CAB) microcapsules. Spherical CAB microcapsules were obtained by oil in water (o/w) solvent evaporation method in the presence of an inert solvent as cyclohexane (CyH) or n-hexane (N-Hex), and different excipients (Phospholipon, Tween, Span, Eudragit RS 100). Chloroform was found to be the best solvent for the preparation of the microcapsules. Also, the sphericity as well as the porosity of the microcapsules was controlled by the presence of an inert solvent. The final concentration of the drug in CAB microparticles was up to 25% (w/w). The key factors for the successful preparation were also the viscosity of the polymer, while the wettability of the resulted microcapsules, the temperature of the preparation, and the porosity have modulated the release of the drug. The higher is the amount of encapsulated microspheres the thinner is the CAB wall between the compartments created by their incorporation. When these microspheres come in contact with the release medium, the pressure created by their swelling breaks the polymer film and the drug starts to be released. The more drug is released in phosphate buffer the higher is the swelling degree of the encapsulated ion exchange resins and the force created by their supplementary swelling will break the more resistants walls. In this way a self-propelled drug release is achieved, until almost all drug was eliberated.
authors.affiliation: Department of Pharmaceutical Sciences, University of Ferrara, I-44100 Ferrara, Italy. ghefun@icmpp.tuiasi.ro
authors.forename: Gheorghe
authors.initials: G
authors.lastname: Fundueanu
authors.forename: Marieta
authors.initials: M
authors.lastname: Constantin
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Esposito
authors.forename: Rita
authors.initials: R
authors.lastname: Cortesi
authors.forename: Claudio
authors.initials: C
authors.lastname: Nastruzzi
authors.forename: Enea
authors.initials: E
authors.lastname: Menegatti
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000737:chemistry; D040761:Biomimetic Materials / Q000737:chemistry; D002214:Capsules / Q000737:chemistry*; D002482:Cellulose / Q000031:analogs & derivatives* / Q000737:chemistry*; D003692:Delayed-Action Preparations / Q000737:chemistry*; D003911:Dextrans / Q000737:chemistry*; D004058:Diffusion; D005750:Gastric Juice / Q000737:chemistry; D005766:Gastrointestinal Contents / Q000737:chemistry; D007475:Ion Exchange Resins / Q000737:chemistry*; D010316:Particle Size; D014677:Pharmaceutical Vehicles / Q000737:chemistry; D013752:Tetracycline / Q000008:administration & dosage* / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D002214:Capsules; D003692:Delayed-Action Preparations; D003911:Dextrans; D007475:Ion Exchange Resins; D014677:Pharmaceutical Vehicles; D002482:Cellulose; C014396:cellulose acetate-butyrate; D013752:Tetracycline