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

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7. RFP Loaded PLGA Coated Chitosan Microspheres Obtained by WSD MethodTable 7.1 : Rfp-Loaded Plga Coated Chitosan Microspheres: CompositionRFP PLGA PVA ChitosanNo Chit. 2mg/ml 2mg/ml 1% -0,1% Chit. 2mg/ml 2mg/ml 1% 0.1%0,25% Chit. 2mg/ml 2mg/ml 1% 0.25%0,5% Chit. 2mg/ml 2mg/ml 1% 0.5%0,75% Chit. 2mg/ml 2mg/ml 1% 0.75%7.2.2. Size and Morphological Characteristics Of MicrospheresMean diameter of the surface-modified PLGA microparticles with different amount ofchitosan, prepared by the WSD method, are shown in Table 7.2. Average diameter of coatedmicrospheres ranged from 2.9 to 1.5 µm, while uncoated PLGA particles had a mean size of2,9 µm. Freeze-dried microspheres, readily redispersed in aqueous medium under manualstirring, showed almost the same particle diameter as that before lyophilization, (data notshown).As can be seen from te table, coating of particles with chitosan led to an increase ofmicrosphere size, which was particularly evident when the lowest amount of the hydrophilicpolymer was used. However this is probably due to the stabilizant effect of PVA/chitosancombination and also to increasing interactions between the two polymers (chitosan andPLGA) as the amount of chitosan increased. Moreover, particle-size distribution did notchange significantly from batch to batch. In fact, polydispersity index of all prepared batcheswas always quite big as a consequence of the high polydispersion of the obtainedformulations. However, no aggregation could be observed as confirmed by SEMinvestigations.108
7. RFP Loaded PLGA Coated Chitosan Microspheres Obtained by WSD MethodTable 7.2: Particle Size and Zeta Potential of RFP-Loaded PLGA Coated ChitosanMicrospheresZeta Potential Zeta PotentialParticle SizeFormulationP.I ± SD (mV ± SD) (mV ± SD)(nm ± SD)Withouth RFP With RFPNo Chit. 2535 ± 58,01 0.506 ± 0,055 +4.70 ± 0.10 -4.80 ± 0.100,1% Chit. 2900 ± 59.54 0.571 ± 0.018 +6.90 ± 0.10 +14.9 ± 0.100,25% Chit. 2807 ± 85.89 0.459 ± 0.053 +8.40 ± 0.20 +19.10 ± 0.400,5% Chit. 2567 ± 19.76 0.494 ± 0.059 +9.40 ± 0.10 +31.10 ± 0.400,75% Chit. 1407 ± 51.23 0.392 ± 0.020 +19.50 ± 0.40 +37.00 ± 0.40As can be seen, a different morphology can be observed from the uncoated and coatedparticles. In fact SEM micrograph 2a shows that uncoated PLGA microspheres have regularand uniform spherical shape with a smoooth surface. However coating PLGA microparticleswith chitosan led to a modification of microspheres surface, which became rough. Figure 7.1.abcdFigure 7.1: Sem Micrographs of RFP-Loaded PLGA Coated Chitosan Microsferes:0,1% chitosan (a and b), 0,75% chitosan (c and d)109
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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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3. Aim of the Work49
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3. Aim of the WorkBiodegradable mic
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4. RFP Loaded Chitosan Microspheres
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4. RFP Loaded Chitosan Microspheres
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