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

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5. RFP Loaded Chitosan Microspheres Prepared by Spray-Drying Methodformulation A is more capable of controlling the drug release than formulation E that releasedthe 90% of the drug in 48 hours at pH 1.2.1001008080% RFP6040% RFP6040202000 20 40 60Time (hours)00 20 40 60Time (hours)Form. AForm. EForm. AForm. EFigure 5.6: Release Studies pH 7.4 Figure 5.7: Release Studies pH 1.25.2.7. Mucoadhesive StudiesAerosol inhalation therapy via the respiratory tract is desirable for delivering drugs since ithas the following advantages over other routes: lung surface area is extremely large andmucosal permeation of drug is comparatively easy because the vascular system is welldeveloped and the walls of alveoli are extremely thin. Finally the intra-cellular or extracellularactivity of drug-metabolizing enzymes is relatively low.Since a strong interaction exists between mucin and chitosan, mucin should be spontaneouslyadsorbed to the surface of the chitosan microspheres. The mucoadhesive behaviour ofchitosan microspheres was assessed by their suspension in different amounts of mucin inaqueous solutions at room temperature. As can be seen in Figure 5.8 the amount of adsorbedmucin increased with increasing mucin concentration. These results confirm that chitosanmicrospheres have the ability to adsorb mucin. The amount of mucin adsorbed was affectedby the presence of the cross-linking agent. In fact cross-linked microspheres interacted with alower amount of mucin, probably because of the cross-linkage and the reduced positive82
5. RFP Loaded Chitosan Microspheres Prepared by Spray-Drying Methodcharge since amino groups are partially neutralized by GA. In fact, for all the batches theamount of mucin adsorbed decreased as the zeta potential of particles decreased.Microspheres with the highest zeta potential (uncross-linked formulations E-H) had thelargest amount of adsorbed mucin.1009080% mucin adsorbed706050403020100A1 A2 A3 B1 B2 B3 C1 C2 C3 D1 D2 D3 E1 E2 E3 F1 F2 F3 G1 G2 G3 H1 H2 H30,025 mg/ml mucin 0,1 mg/ml mucin 0,5 mg/ml mucinFigure 5.8: Mucoadhesive Studies of Spry-Dried Chitosan Microspheres5.3. ConclusionsResults obtained during this work showed that the spray drying method is a rapid and simpletechnique for producing RFP loaded microspheres in good yields, high E% and goodreproducibility from batch to batch. In particular, microspheres prepared by this methodshowed to possess suitable properties for aerosol delivery. In fact comparison of results withthose obtained with the precipitation method pointed out that microparticles prepared by thespray-drying process showed higher stability during nebulization.83
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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
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
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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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Page 120 and 121: 8. Final Discussion and Conclusions
Page 122 and 123: 9. References9. References1. Fred S
Page 124 and 125: 9. References40. Wayne L.G., Good R
Page 126 and 127: 1269. References88. Carpenter R.L.
Page 128 and 129: 1289. References135. Fukushima S.;
Page 130 and 131: 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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