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|Title: ||Preparation and characterization of spray dried inclusion complex between andrographolide and cyclodextrins|
|Other Titles: ||Pen wu gan zao huan hu jing bao he chuan xin lian nei zhi de zhi bei he te xing yan jiu|
|Authors: ||Lai, Wai Ping (賴慧冰)|
|Department: ||Department of Biology and Chemistry|
|Degree: ||Master of Philosophy|
|Issue Date: ||2009|
|Publisher: ||City University of Hong Kong|
|Notes: ||CityU Call Number: QK495.A1655 L34 2009|
xix, 164 leaves : ill. 30 cm.
Thesis (M.Phil.)--City University of Hong Kong, 2009.
Includes bibliographical references (leaves 150-164)
|Abstract: ||Andrographolide (Andro) is the major bioactive component in Andrographis paniculata. Recent studies showed that Andro possesses promising anticancer effect by inducing apoptosis of various malignant cells in vitro and has significant hepatoprotective and immunostimulative functions. However, being a class of diterpene lactone, Andro is hardly soluble in water. It is also unstable under neutral and alkaline condition and may subject to the multi-drug efflux by P-glycoprotein (Pgp) in the GI tract. To address the shortcomings of Andro, the compound was molecularly encapsulated by cyclodextrins as inclusion complexes. Effects of mixing ratio between Andro and cyclodextrins (CDs) were studied. Good complexation was found in the mixture of Andro-βCD and Andro-yCD at a molar ratio of 1:2 while unreacted Andro was still detectable in the mixture of Andro-HPβCD at any molar ratios. Spray drying of Andro-βCD and Andro-yCD at an inlet temperature of 150oC and feed rate of 5 ml/min produced particle size of the complex down to 948 and 837 nm. The physicochemical properties of the spray dried binary systems of Andro-CDs and ternary system of Andro-CDs-polymers were characterized by X-ray diffractometry, Fourier transform-infrared spectrometry, differential scanning calorimetry, scanning electron microscopy, moisture content analysis and particle size analysis. Addition of polymeric additives, namely HPMC and PVP, had no improvement on the performances of AndroCDs. When the interaction of Andro and CDs complexes was evaluated by the profiles of phase solubility in aqueous environment, it revealed that Andro-HPβCD and Andro-yCD were the AL-type interaction and Andro-βCD was the BS-type interaction. The stoichiometry of the complex between Andro and CD was 1:1 in the aqueous solution. Since the stability constant (Kc) of Andro-yCD complexes was the largest based on the phase solubility study, it suggests that the highest extent of complex formation was between Andro and yCD. The dissolution performance and stability of each type of complexes were determined at different pHs. Feeding rate of spray dryer was found to play an important role against hydrolytic degradation of Andro. Lower feed rate could enhance the stability of Andro in the inclusion complex. It was found that Andro-βCD at 1:2 molar ratio spray dried at inlet temperature of 150oC and feed rate of 5 ml/min gave the best performance of dissolution; it was about 100% better than pure drug and the stabilizing effect on degradation of Andro was the best in comparison to the other two CDs.|
|Online Catalog Link: ||http://lib.cityu.edu.hk/record=b2367225|
|Appears in Collections:||BCH - Master of Philosophy |
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