title: Drug-polymer microparticles produced by supercritical assisted atomization.
abstract: The supercritical assisted atomization (SAA) was proposed as a new technique to produce composite microparticles for drug controlled release. Ampicillin trihydrate and chitosan were selected as model drug and carrier, respectively, and 1% v/v acetic acid aqueous solution was used as solvent. The effect of the polymer/drug ratio on particle morphology and drug release rate was evaluated. SEM analysis indicated that non-coalescing spherical microparticles formed by chitosan/ampicillin were produced by SAA. All coprecipitates produced have a sharp particle distribution, with diameters ranging between about 0.1 and 6 microm. SAA composite microparticles were characterized by X-ray, DSC, EDX and UV-vis analysis. A solid solution of the chitosan and ampicillin was produced and a stabilizing effect of the polymer on the drug has resulted that protects ampicillin from thermal degradation. A prolonged release from SAA coprecipitates with respect to raw drug and physical mixtures of chitosan and ampicillin was obtained; moreover, the polymer/drug ratio has revealed to be a controlling parameter for drug release. Drug release mechanisms characteristic of swelling-controlled systems were observed, with ampicillin release depending on both relaxation and diffusive mechanisms. An empirical binomial equation was used to describe experimental data, showing a fair good agreement with ampicillin release data if both the relaxational and the diffusional parameters are function of the polymer/drug ratio.
authors.affiliation: Dipartimento di Ingegneria Chimica e Alimentare, Università degli Studi di Salerno, Via Ponte Don Melillo, 84084 Fisciano (SA), Italy. ereverchon@unisa.it
authors.forename: Ernesto
authors.initials: E
authors.lastname: Reverchon
authors.forename: Alessandra
authors.initials: A
authors.lastname: Antonacci
mesh_terms: D000667:Ampicillin / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry*; D025924:Chromatography, Supercritical Fluid / Q000379:methods*; D003198:Computer Simulation; D003692:Delayed-Action Preparations / Q000737:chemistry*; D004058:Diffusion; D004337:Drug Carriers / Q000737:chemistry*; D004339:Drug Compounding / Q000379:methods*; D005740:Gases / Q000737:chemistry; D008422:Materials Testing; D008863:Microspheres; D008956:Models, Chemical; D010316:Particle Size
chemical_list: D003692:Delayed-Action Preparations; D004337:Drug Carriers; D005740:Gases; D000667:Ampicillin; D048271:Chitosan