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Chitosan and PLGA microspheres as drug delivery system against pulmonary mycobacteria infections

Manca, Maria Letizia (2007) Chitosan and PLGA microspheres as drug delivery system against pulmonary mycobacteria infections. [Doctoral Thesis]

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Abstract

Various types of rifampicin (RIF)-loaded microparticles were compared for their stability during nebulization. Poly(lactide-co-glycolide) (PLGA), chitosan (CHT) and PLGA/CHT microparticles (MPs) were prepared by emulsion, precipitation or spray-drying techniques. MPs ability to be nebulized (NE%) as well as stability during freeze-drying or/and nebulization (NEED%), were evaluated after RIF extraction from MPs and determination by light spectroscopy. MP mean diameters and zeta-potential values were measured by dynamic light scattering, morphology was assessed by SEM, cytotoxicity by MTT method and mucoadhesive properties by mucin association. In all cases, freeze-drying prior to nebulization did not affect EE%, NE or NEED%. In CHT, MPs RIF encapsulation efficiency (EE%) decreased with increasing CHT concentration (viscosity) and CHT-MP NEED% was higher when the polymer was crosslinked by glutaraldehyde. PLGA MPs, exhibited both higher RIF EE% and also higher nebulization ability and NEED%, compared to CHT ones, but also higher cytotoxicity. However, when the two polymers were combined in the PLGA/CHT MPs, EE%, NE% and NEED% increased with increasing MP CHT-content. PLGA/CHT MPs with 0.50% or 0.75% CHT exhibited highest EE% for RIF and also best nebulization ability and stability, compared to all other MP formulations studied. Additionally they had good mucoadhesive properties and comparably low cytotoxicity.

Item Type:Doctoral Thesis
Date:28 February 2007
Tutor:Fadda, Anna Maria, Valenti, Donatella
PhD classes:Ciclo 18 > Tecnologie e legislazione del farmaco e delle molecole bioattive
Coordinator:Podda, Gianni
Institution:Universita' degli Studi di Cagliari
Divisions:Dipartimenti (fino a dicembre 2011) > Dipartimento Farmaco chimico tecnologico
Subjects:Area 03 - Scienze chimiche > CHIM/09 Farmaceutico tecnologico applicativo
Uncontrolled Keywords:Microparticle, PLGA, Chitosan, Rifampicin, Nebulization, Encapsulation; Stability, Mucoadhesion, Cytotoxicity
ID Code:130
Deposited On:04 Nov 2008 10:40

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