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

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4. RFP Loaded Chitosan Microspheres Prepared by Precipitation Method% of Mucin Adsorbed100806040200Form.1 Form.2 Form.3 Form.4 Form.5 Form.60,025 mg/ml Mucin Solution 0,1 mg/ml Mucin Solution0,5 mg/ml Mucin SolutionFigure 4.10: Mucoadhesive Studies of Chitosan Microspheres4.2.8. 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 free andmicrosphere-encapsulated RFP. This study was carried out only on Formulation 1 (uncrosslinked)and Formulation 4 (cross-linked), which had been prepared with 0.25% of chitosan.Cytotoxicity was observed to be RFP concentration-dependent for all the tested samples(Figure 4.11). The highest cytotoxic effects were found for free RFP, which even in thelowest concentration (0.1%) showed only a 55% cell viability that further decreased to 12%when the free drug was used in the highest concentration (0.5%). These results show the hightoxicity of RFP that can cause side effects also when it is nebulized directly into the lung,where is the site of infection. The viability assay also showed that RFP toxicity can bereduced by encapsulating the drug in chitosan microspheres. Cell viability was generally notaffected by chitosan concentration, in fact empty particles showed always the best results interm of viability. As can be seen in figure 4.11 the presence of GA decreased the viability ofcells probably because same cross-linking agent was in the particles also after the purificationsteps.68
4. RFP Loaded Chitosan Microspheres Prepared by Precipitation Method10080Viability60402000,1 0,25 0,5 EmptyForm. 1 Form. 4 RFP SolutionFigure 4.11: Viability Studies whit A549 Cells4.3. ConclusionChitosan is a versatile polymer whose applications range from weight supplement in themarket to a drug carrier in formulation research. Cross-linking agents such as GA has beenused for preparation of microspheres. The particle size of chitosan microspheres can bemodified approximately for the pulmonary delivery of drugs. The entrapment efficiency ofdrugs in the chitosan microspheres is dependent upon the chitosan concentration. Also therelease of drug from chitosan microspheres is dependent upon the concentration of chitosan,but also upon drug content and density of cross linking.The potential bioadhesiveness of these microspheres are important properties required for thetreatment of MTB and MAC infections. Taking together the good bioacceptibility of chitosan,its positive charge that seems to be very advantageous for bioadhesion to the normallynegatively charged biological membranes, the suitable release profile for RFP, the possibilityto modulate RFP release from chitosan microspheres by adding cross-linking agent (GA), theabove presented microspheres may represent useful tools for the delivery of antituberculardrug by aerosol therapy.69
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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
Page 18 and 19: 1. General Introductionhighly vascu
Page 20 and 21: 201. General Introductionliquid (84
Page 22 and 23: 1. General IntroductionAerosol size
Page 24 and 25: 1. General Introductionof numerous
Page 26 and 27: 1. General Introductionintermittent
Page 28 and 29: 1. General Introductionsphere prepa
Page 30 and 31: 1. General Introductionit, respecti
Page 32 and 33: 1. General Introductionthe subject
Page 34 and 35: 1. General IntroductionA. zahoor et
Page 36 and 37: 2. Chitosan And PLGA2.1. Chitosan a
Page 38 and 39: 2. Chitosan And PLGAfor the prepara
Page 40 and 41: 2. Chitosan And PLGAmainly controll
Page 42 and 43: 2. Chitosan And PLGAAt present, a n
Page 44 and 45: 2. Chitosan And PLGAneed to be a go
Page 46 and 47: 2. Chitosan And PLGAdichloromethane
Page 49 and 50: 3. Aim of the Work49
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
Page 83: 5. RFP Loaded Chitosan Microspheres
Page 86 and 87: 6. RFP Loaded PLGA Microspheres Pre
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Page 102 and 103: 7. RFP Loaded PLGA Coated Chitosan
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8. Final Discussion and Conclusions
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9. References9. References1. Fred S
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9. References40. Wayne L.G., Good R
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1269. References88. Carpenter R.L.
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1289. References135. Fukushima S.;
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9. References173. Zeng X.M., Martin
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9. References219. Berthold A., Crem
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9. Referencesmediates target gene e
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