chitosan and plga microspheres as drug delivery ... - UniCA Eprints

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6. RFP Loaded PLGA Microspheres Prepared by Solvent Evaporation Method30% Mucin Adsorbed25201510500,025 mg/ml mucin 0,1 mg/ml mucin 0,5 mg/ml mucinFigure 6.7: Mucoadhesive Properties of PLGA Microspheres6.2.8. Viability Studies with A549 CellsThe cytotoxic effects of RFP against A549 cells were examined by MTT assay. In theexperiments, the cytotoxicity was evaluated by varying the concentration of RFP and RFPentrapped in PLGA microspheres. Cytotoxicity was observed to be concentration-dependentfor free RFP and for the formulations. Higher cytotoxic effects were found for free RFP. Infact, as can be seen in figure 6.8, also with the lowest concentration of RFP the viability isvery low. This means that the free drug can cause side effects when it is nebulized directlyinto the lung, where the infection is. Even using the smallest concentration, the free RFP isable to kill the lung cells (epithelial cells similar to A549 cells). As written before, the targetof this work was especially the macrophages where mycobacteria are able to survive andreplicate. As can be seen from the figure, encapsulation of RFP in the PLGA microspheres ledto a decrease of the cytotoxicity, which was quite close to that of the free drug only at thelowest tested RFP concentration .98
6. RFP Loaded PLGA Microspheres Prepared by Solvent Evaporation Method10080Viability60402000,1 0,25 0,5 EMPTYPLGARFP SolutionFigure 6.8: Viability Studies with A549 Cells6.3. ConclusionsResults obtained during this study have shown that PLGA microspheres can lead RFP in verygood yields. These particles showed good properties and stability during nebulization.Summarizing the results of this study, we may conclude that with the exception of theirsubstantially lower mucoadhesive properties, the PLGA polymer is better that chitosan, forthe formation of particles that could deliver RFP to alveolar macrophages by nebulisation.Thereby, an interesting addition to the properties of RIF-loaded PLGA particles would be toimprove their mucoadhesive properties through surface modification.99
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European Union Ministero dell’Uni
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Table Of Contents1. GENERAL INTRODU
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7.1.4. Release Studies/Stability St
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1. General Introduction1.1. Pulmona
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1. General Introductionmucosa, and
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1. General Introductionis the fact
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1.3. Lung Anatomy1. General Introdu
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1. General Introductionhighly vascu
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201. General Introductionliquid (84
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1. General IntroductionAerosol size
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1. General Introductionof numerous
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1. General Introductionintermittent
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1. General Introductionsphere prepa
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1. General Introductionit, respecti
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1. General Introductionthe subject
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1. General IntroductionA. zahoor et
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2. Chitosan And PLGA2.1. Chitosan a
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2. Chitosan And PLGAfor the prepara
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2. Chitosan And PLGAmainly controll
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2. Chitosan And PLGAAt present, a n
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2. Chitosan And PLGAneed to be a go
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2. Chitosan And PLGAdichloromethane
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Page 51: 3. Aim of the WorkBiodegradable mic
Page 54 and 55: 4. RFP Loaded Chitosan Microspheres
Page 71 and 72: 5. Rifampicin Loaded ChitosanMicros
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Page 102 and 103: 7. RFP Loaded PLGA Coated Chitosan
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Page 120 and 121: 8. Final Discussion and Conclusions
Page 122 and 123: 9. References9. References1. Fred S
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Page 128 and 129: 1289. References135. Fukushima S.;
Page 130 and 131: 9. References173. Zeng X.M., Martin
Page 132 and 133: 9. References219. Berthold A., Crem
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