Nanotechnological delivery systems for the oral administration ofactive molecules: Polymeric microparticles and microemulsions applied to anti-inflammatory and anti-infectious drugs

摘要

This thesis was devoted to the development of innovative oral delivery systems for twodifferent molecules. In the first part, microparticles (MPs) based on xylan and Eudragit® S-100 were produced and used to encapsulate 5-aminosalicylic acid for colon delivery. Xylanwas extracted from corn cobs and characterized in terms of its physicochemical, rheologicaland toxicological properties. The polymeric MPs were prepared by interfacial cross-linkingpolymerization and spray-drying and characterized for their morphology, mean size anddistribution, thermal stability, crystallinity, entrapment efficiency and in vitro drug release.MPs with suitable physical characteristics and satisfactory yields were prepared by bothmethods, although the spray-dried systems showed higher thermal stability. In general, spraydriedMPs would be preferable systems due to their thermal stability and absence of toxicagents used in their preparation. However, drug loading and release need to be optimized. Inthe second part of this thesis, oil-in-water microemulsions (O/W MEs) based on mediumchaintriglycerides were formulated as drug carriers and solubility enhancers for amphotericinB (AmB). Phase diagrams were constructed using surfactant blends with hydrophiliclipophilicbalance values between 9.7 and 14.4. The drug-free and drug-loaded MEs presentedspherical non-aggregated droplets around 80 and 120 nm, respectively, and a lowpolydispersity index. The incorporation of AmB was high and depended on the volumefraction of the disperse phase. These MEs did not reduce the viability of J774.A1macrophage-like cells for concentrations up to 25 μg/mL of AmB. Therefore, O/W MEsbased on propylene glycol esters of caprylic acid may be considered as suitable deliverysystems for AmB