Nifedipine loaded chitosan microspheres prepared by emulsification phase-separation |
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Authors: | S Dhawan AK Singla |
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Affiliation: | 1. University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh, India, 160014kdd@glide.net.in sanjudhawan@rediffmail.com;3. University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh, India, 160014 |
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Abstract: | A high yield of nifedipine-chitosan microspheres could be obtained using an emulsification phase-separation method. A high level of entrapment of nifedipine in the microspheres was achieved. The microspheres exhibited excellent swelling properties. Differential scanning calorimetry, X-ray diffractometry, and scanning electron microscopy confirmed that at 1.84% loading, nifedipine was dispersed molecularly. The microspheres exhibited faster release at low loadings compared to high loadings. Fitting the data to the coupled Fickian/case II equation, showed that at low loadings polymer relaxation coefficients (k2) were high. As the polymer content increased in the microspheres, the value of n (diffusional exponent characteristic of the release mechanism) approached one, which is indicative of zero order. |
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Keywords: | chitosan diffusional exponent emulsification phase-separation swelling |
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