Study of Ethyl Cellulose—Benzoic Acid Interactions in Matrices for Controlled Drug Release by DSC |
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| Authors: | Singhal R Nagpal A K Mathur G N |
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| Institution: | (1) Department of Plastic Technology, Harcourt Butler Technological Institute, Kanpur, 208 002, India;(2) Defence Material Stores Research and Development Establishment, Kanpur, 208 013, India |
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| Abstract: | The physical state of benzoic acid (BA) and its interaction with ethyl cellulose (EC) were examined in ethyl cellulose—benzoic acid matrices by Differential Scanning Calorimetry (DSC). The glass transition temperature (Tg) of EC of various matrices having BA in solid solution form (upto 27.7%) was reduced. The BA in matrices containing more than 38.9% drug exhibited distinct melting endotherms due to crystalline form. The peak temperatures of these endotherms were lowered and they broadened as the concentration was lowered. The solubility of BA increased at its melting point as compared to ambient temperature. The melting enthalpy of BA, when plotted as a function of its concentration yielded a straight line with intercept of 330 mg g–1 of matrix. This is the solubility of BA in EC at its melting temperature. Fourier Transform Infra Red Spectroscopy (FTIR) investigations confirmed that hydrogen bonding occurred between EC and BA through hydroxyl groups.This revised version was published online in November 2005 with corrections to the Cover Date. |
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| Keywords: | benzoicacid controlled release DSC ethyl cellulose FTIR |
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